Entries |
Document | Title | Date |
20090028563 | OPTICAL TRANSMISSION/RECEPTION DEVICE AND OPTICAL COMMUNICATION SYSTEM USING THE SAME - An optical transmission/reception device includes at least one light emitting portion and at least one light receiving portion on the same substrate. The light emitting portion includes at least a lower multilayer reflector and an active layer provided on the lower multilayer reflector. A metal layer including a plurality of opening portions is provided in an upper portion of the light emitting portion. Each of the opening portions has a size smaller than a light emission wavelength of the light emitting portion. | 01-29-2009 |
20090060508 | Polarization multiplexing and transmitting apparatus - A polarization multiplexing and transmitting apparatus generates polarization multiplexed light by multiplexing modulated signal components that having varying intensities and are in polarization states orthogonal to each other. The polarization multiplexing and transmitting apparatus includes a converting unit that converts light generated by a light source into signal components having a varying intensity synchronized with a clock signal input thereto and a varying intensity inversely synchronized with the clock signal, respectively; a modulating unit that modulates the signal components, respectively; and a polarization adjusting unit that orthogonalizes polarization states of the signal components. | 03-05-2009 |
20090103921 | OPTICAL RECEIVER SYSTEMS AND METHODS FOR POLARIZATION DEMULTIPLEXING, PMD COMPENSATION, AND DXPSK DEMODULATION - A simplified optical receiver architecture capable of tracking and demultiplexing polarization-multiplexed signals, dynamically compensating for PMD using a variety of polarization controller technologies, and reducing the number of delay line demodulators by two for both DPSK and DQPSK modulation is illustrated. Once polarization is stabilized at the first stage of the cascaded system of the present invention, subsequent stages can be simplified and cost reduced. | 04-23-2009 |
20090129778 | RAMAN CANCELLATION AND MANAGEMENT IN CATV TRANSPORT AND DISTRIBUTION VIA RF SPECTRUM INVERSION - Provided herein are at least one embodiment of a system and method for reducing or eliminating crosstalk and associated distortion in a wavelength-division multiplexed optical signal transmitted over a fiber optic network by inversion of the RF signals that are inputs to the system. | 05-21-2009 |
20090148164 | SIGNAL EQUALIZER IN A COHERENT OPTICAL RECEIVER - A signal equalizer for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments. | 06-11-2009 |
20090169208 | SYSTEMS AND METHODS FOR THE POLARIZATION INSENSITIVE COHERENT DETECTION AND THE POLARIZATION DIVISION MULTIPLEXED TRANSMISSION OF OPTICAL COMMUNICATION SIGNALS - The present invention relates generally to the transport and processing of optical communication signals. More specifically, the present invention relates to systems and methods for the polarization insensitive coherent detection of optical communication signals with Brillouin amplification of the associated signal carrier and the polarization division multiplexed transmission of optical communication signals without polarization tracking at the associated receiver(s). | 07-02-2009 |
20090196610 | Optical reception apparatus compatible with DQPSK polarization multiplexing format - In the optical reception apparatus, a DQPSK polarization multiplexed signal light (S) input thereto is split into horizontally/vertically polarized signal lights (S | 08-06-2009 |
20090202243 | Direct Detection For Receiving Polarization Multiplexing Signals - There is provided a method for detecting optical signals comprising employing a photo diode to both directly detect a received optical signal and convert it into an electrical signal for recovery of data bit stream information in the received optical signal, the received optical signal being derived from a separation of two polarization multiplexed optical signals that were combined before being received. | 08-13-2009 |
20090214210 | 100 Gbit/s OFDM Optical Signal Generation - A method includes modulating lightwaves to provide first and second OFDM signal sidebands at a first polarization direction and first and second OFDM signal sidebands at a second polarization direction, and combining sidebands that are oppositely positioned and joined from the first and second OFDM signal sidebands at each polarization direction to provide a polarization multiplexing OFDM signal. | 08-27-2009 |
20090232500 | TRANSAMPLIFIER, SYSTEM AND METHOD FOR AMPLIFICATION OF OPTICAL SIGNALS AT PLURAL WAVELENGTHS - Disclosed herein are embodiments of a device, method of use and system for an analog multi-wavelength transamplifier. The transamplifier embodiments described herein allow the use of multiple wavelengths to segment logical service groups, such as for use in a CATV distribution system and a FTTH system having a broadband overlay. Improved optical signal power performance can be achieved by using direct modulating transmitters and maintaining polarization of the optical signals that are modulated by a phase modulator, such as an external waveguide. | 09-17-2009 |
20090274460 | DIFFERENTIAL DELAY RECEIVER USING CROSS-POLARIZATION INTERFEROMETER FOR POLMUX-DPSK SYSTEM - A differential delay detection system and method includes an optical splitter to split an incoming optical signal between a first path and a second path. The first path includes a cross-polarization interferometer configured to separately generate polarization independent outputs using split paths and to generate cross-polarization interference outputs, and a polarization demultiplexer configured to combine the polarization independent outputs and the cross-polarization interference outputs from the cross-polarization interferometer with updated coefficients received from the second path to remove the cross-polarization mixed signals, The second path includes a training signal receiver configured to compute the updated coefficients and output the updated coefficients to the polarization demultiplexer. | 11-05-2009 |
20090279891 | ALL-OPTICAL WAVELENGTH CONVERSION FOR A POLARIZATION MULTIPLEXING OPTICAL SIGNAL - An apparatus includes a first laser source for providing a first lightwave; a first optical coupler that is polarization maintaining for dividing the first lightwave into first and second optical carrier lightwaves; first and second modulators for modulating respective ones of the first and second carrier lightwaves with information; a polarization beam combiner for combining the modulated first and second carrier lightwaves which generates a polarization multiplexing optical signal; second and third lasers for providing second and third lightwaves whose wavelengths are one of both longer than that of the first lightwave and shorter than that of the first lightwave, a second optical coupler that is polarization maintaining for combining the second and third lightwaves; and a third optical coupler for combining the modulated first and second carrier lightwaves from the polarization beam combiner and the combined second and third lightwaves out of the second optical coupler for transmission over an optical medium. | 11-12-2009 |
20090290874 | MONITORING APPARATUS AND METHOD FOR POLARIZATION SCRAMBLER AND OPTICAL TRANSMISSION APPARATUS - There are provided a polarized light passing device to pass therethrough specific polarized light, of output light of a polarization scrambler; and a detecting unit to detect a modulation component according to a frequency of a polarization control signal from the light which passes through the polarized light passing device. | 11-26-2009 |
20090310965 | Optical Transmission System and Device for Receiving an Optical Signal - The invention concerns a device ( | 12-17-2009 |
20090310966 | DIRECT DETECTION RECEIVER USING CROSS-POLARIZATION INTERFEROMETER FOR POLMUX-ASK SYSTEM - A differential delay detection system and method includes an optical splitter to split an incoming optical signal between a first path and a second path. The first path includes a cross-polarization interferometer configured to separately generate polarization independent outputs using split paths and to generate cross-polarization interference outputs, balanced photodetectors to aid in removing cross-polarization beating noise, and a polarization demultiplexer configured to combine the polarization independent outputs and the cross-polarization interference outputs from the cross-polarization interferometer with updated coefficients received from the second path to remove the cross-polarization mixed signals. The second path includes a training signal receiver configured to compute the updated coefficients and output the updated coefficients to the polarization demultiplexer. | 12-17-2009 |
20090324223 | System, method and apparatus for channel estimation with dual polarization training symbols for coherent optical OFDM - System, apparatus and method of optical communication are provided for performing channel estimation for an optical OFDM system by utilizing correlated dual-polarization training symbols (CDPTS) to offer high system tolerance to fiber nonlinear effects such as cross-phase modulation (XPM) among wavelength-division multiplexed (WDM) channels. An exemplary method includes receiving a pair of dual-polarization or polarization-multiplexed training symbols in an optical polarization-division multiplexed (PDM) orthogonal frequency-division multiplexed (OFDM) signal, and performing channel estimation to obtain an estimated channel matrix for at least a first of a plurality of subcarriers of the PDM-OFDM signal. Channel compensation is performed based on the estimated channel matrix for at least the first subcarrier of the OFDM signal and symbols then decoded. | 12-31-2009 |
20090324224 | System, method and apparatus to suppress inter-channel nonlinearities in WDM systems with coherent detection - For optical communications, apparatus and methods are provided for performing dispersion compensation management that suppresses intra-channel nonlinearities, inter-channel cross-phase modulation (XPM) and/or nonlinear polarization scattering. In optical communication, in which wavelength division multiplexed (WDM) channels are modulated, detecting and measuring channels with coherent detection is complicated due to impairments caused by neighboring channels. Apparatus and methods are provided which reduce the effect of impairments by performing in-line Periodic Group Delay (PGD) dispersion compensation on a WDM signal so as to enable detection of individual channels without severe degradation of system performance. Preferably the PGD dispersion compensator has within a channel a chromatic dispersion substantially similar to a DCF and between channels the group delay is substantially similar. | 12-31-2009 |
20100003028 | FILTER COEFFICIENT ADJUSTMENT APPARATUS - In present invention, a filter coefficient adjustment apparatus is used in a polarization demultiplexer which demultiplexes the input signals by using filters to obtain demultiplexed output signals, said filter coefficient adjustment apparatus being used for adjusting the coefficients of the filters, wherein said filter coefficient adjustment apparatus comprises: an logarithm partial derivative calculation unit for calculating the logarithm partial derivative value of a target probability density function of the demultiplexed output signals when its self-variable value is the present demultiplexed output signal value; a gradient calculation unit for calculating the gradient of a target optimizing function for optimizing the distribution of the multiplexed output signals based on the logarithm partial derivative value calculated by the logarithm partial derivative calculation unit; and a filter coefficient updating unit for updating the coefficients of the filters based on the gradient calculated by the gradient calculation unit. | 01-07-2010 |
20100021163 | METHOD AND SYSTEM FOR POLARIZATION SUPPORTED OPTICAL TRANSMISSION - A method comprising splitting a received optical signal into split optical signals, the split optical signals being at least initially orthogonally polarized, coherently detecting at least one of the split optical signals and generating an electrical signal indicative thereof, and processing said electrical signal, the processing being adapted for received optical signals with orthogonal frequency division multiplexing (OFDM) modulation. A transmission system, a transmitter and a receiver are also provided. | 01-28-2010 |
20100034537 | FREQUENCY OFFSET POLARIZATION MULTIPLEXING MODULATION FORMAT AND SYSTEM INCORPORATING THE SAME - An apparatus, system and method wherein a polarization multiplexed differential phase shift keying format (POLMUX-DPSK) is provided with offset and bit-interleaved frequency channels and demodulated using a DPSK demodulator. | 02-11-2010 |
20100054737 | Parallel Optical Polarization Tracking - A system to communicate optical data signals in parallel includes an optical splitter to split the data signals into two polarization multiplexed (PM) signals; and two reception channels coupled to the optical splitter, where each reception channel tracks and isolates a PM signal independently. | 03-04-2010 |
20100054738 | CONTROL APPARATUS, POLARIZATION MULTIPLEXING LIGHT MODULATOR, LIGHT TRANSMITTING APPARATUS, AND METHOD OF CONTROLLING POLARIZATION MULTIPLEXING LIGHT MODULATOR - The present invention provides a control apparatus including: an output monitor which monitors polarization-multiplexed output light output from a polarization multiplexing light modulator which modulates light of two systems independent of each other, polarization-multiplexes light signals of the two systems subjected to the light modulation, and outputs the polarization-multiplexed light signals; and a control unit which controls a delay time difference at a stage where the light signals of the two systems forming the polarization multiplexing light modulator are polarization-multiplexed based on a monitor result of the output monitor. The control apparatus controls a delay time difference between polarization channels easily or surely. | 03-04-2010 |
20100086303 | HIGH SPEED POLMUX-OFDM USING DUAL-POLMUX CARRIERS AND DIRECT DETECTION - A polarization multiplexing, orthogonal frequency division multiplexing (POMUX) transmission system utilizing direct detection. | 04-08-2010 |
20100098420 | POLARIZATION MONITORING IN POLARIZATION DIVISION MULTIPLEXING IN OPTICAL COMMUNICATIONS - Systems and techniques for optical communications based on polarization division multiplexing are described. | 04-22-2010 |
20100104284 | System, method and apparatus for joint self phase modulation compensation for coherent optical polarization-division-multiplexed orthogonal-frequency division-multiplexing systems - System, apparatus and method of optical communication are provided for performing digital compensation of the self-phase modulation (SPM) effect experienced by a polarization-division multiplexed (PDM) orthogonal frequency-division multiplexed (OFDM) signal in fiber transmission by compensating a complex digital waveform representing one orthogonal polarization component of the optical PDM-OFDM signal based on both digital waveforms representing two orthogonal polarization components of the PDM-OFDM signal. The compensation of the digital waveform may be further based on an anticipated mean total nonlinear phase shift experienced by the signal during fiber transmission due to SPM. The compensation may be divided into pre-compensation at the PDM-OFDM transmitter and post-compensation at the PDM-OFDM receiver. The fiber transmission link preferably includes a pre-dispersion compensation module, distributed inline dispersion compensation modules, and a post-dispersion compensation module arranged in a judiciously chosen manner. | 04-29-2010 |
20100111530 | POLARIZATION MODE DISPERSION COMPENSATION AND POLARIZATION DEMULTIPLEXING SYSTEMS AND METHODS FOR OPTICAL TRANSMISSION SYSTEMS - The present disclosure provides polarization mode dispersion compensation (PMDC) and polarization de-multiplexing systems and methods for polarization multiplexed (PolMux) optical transmission systems. The PMDC detects an error signal before a polarization splitter in PolMux systems for controlling polarization controllers (PC) and/or DGDs in the PMDC for return-to-zero (RZ) differential m-phase shift keying (DmPSK) signals. For bit-aligned PolMux systems, the error signal could be the level of clock frequency at one, two, or more times of the baud rate at one polarization. For bit-interleaved PolMux systems, the error signal could be the level of clock frequency at two times of the baud rate at one polarization. The PMDC can operate in PolMux systems with any arbitrary time offset between the two polarizations. The polarization de-multiplexer utilizes error detection at both output arms of a polarization splitter to mitigate PDL impact on any PolMux type of signal. | 05-06-2010 |
20100111531 | OPTICAL TRANSMISSION/RECEPTION SYSTEM, OPTICAL TRANSMITTER, OPTICAL RECEIVER, AND OPTICAL TRANSMISSION/RECEPTION METHOD - An optical transmission/reception system includes a modulator for modulating light based on data to output signal light; a transmission-side signal processor performing transmission-side digital signal processing which imparts a polarization change to the signal light by the optical modulation with respect to an input signal; an optical transmitter in which the modulator performs the optical modulation based on the input signal subjected to the transmission-side digital signal processing in the transmission-side signal processor; and an optical receiver including a converter converting the signal light inputted from the optical transmitter via a transmission path to a digital electric signal for each polarization component, and a reception-side signal processor performing reception-side digital signal processing which imparts a polarization change having a property substantially inverse to a property of the polarization change in the transmission-side signal processor with respect to the digital electric signal from the converter. | 05-06-2010 |
20100142951 | RECEPTION OF SIGNALS TRANSMITTED OVER A DISPERSIVE OPTICAL CHANNEL - A receiver for recovering transmitted information carried by a received optical signal that has been affected by dispersion includes an optical splitter having an input port arranged to receive the received optical signal, and a plurality of output ports. A proportion of optical power at the input port is transmitted to each of the output ports. A plurality of optical detectors is operably connected to respective output ports of the optical splitter, for generating a corresponding plurality of electrical signals. Optical phase shifters are disposed between the output ports of the optical splitter and respective optical detectors. As a result, each optical phase shifter applies a frequency dependent phase shift to an optical signal passing therethrough. An electronic processor includes analog and/or digital electronic components configured to combine two or more of the plurality of electrical signals, or information recovered separately therefrom, in order to provide improved accuracy or reliability of information recovery as compared with detecting and processing only the received optical signal. The receiver is advantageously able to mitigate the effects of frequency-dependent fading which may occur in intensity modulation/direct detection optical transmission systems due to dispersion in optical transmission paths. | 06-10-2010 |
20100142952 | ADAPTIVE CROSSING FREQUENCY DOMAIN EQUALIZATION (FDE) IN DIGITAL POLMUX COHERENT SYSTEMS - A method for the polarization independent frequency domain equalization (FDE) on polarization multiplexing (POLMUX) coherent systems employing an adaptive crossing FDE which advantageously produces CD compensation, PMD compensation and PolDeMux within one functional block of a digital signal processor (DSP). | 06-10-2010 |
20100150555 | Automatic polarization demultiplexing for polarization division multiplexed signals - Method and apparatus are provided for polarization demultiplexing for a Polarization Division Multiplexed (PDM) signal stream in the optical domain. The optical PDM signal stream includes a first channel representing a first data stream and a second channel representing a second data stream, a time delay between the first channel and the second channel. A Polarization Beam Splitter (PBS) demultiplexes an optical PDM signal into the first channel and the second channel. An associated processing block obtains one of the channels and provides a Polarization Controller with for a control signal corresponding to the power level of the low frequency portion of the RF spectrum of the channel obtained. Based on the control signal, the Polarization Controller adjusts a state of polarization of the optical PDM signal stream that is provided to the PBS for demultiplexing. | 06-17-2010 |
20100158521 | OPTICAL MIXER FOR COHERENT DETECTION OF POLARIZATION-MULTIPLEXED SIGNALS - An optical mixer that, in one embodiment, has a single optical hybrid optically coupled to a single polarization beam splitter. The optical hybrid mixes a polarization-multiplexed optical communication signal and a local-oscillator signal to generate four mixed signals, each corresponding to a different relative phase shift between the communication and local-oscillator signals. The polarization beam splitter separates each of the mixed signals into two polarization components, subsequent processing of which enables an optical receiver employing the optical mixer to recover the data carried by the communication signal. | 06-24-2010 |
20100158522 | SEED LIGHT MODULE BASED ON SINGLE LONGITUDINAL MODE OSCILLATION LIGHT SOURCE - A seed light module based on a single longitudinal mode oscillation light source is provided. The seed light module includes a multi-wavelength signal generation light source unit generating a continuous wave (CW) of different wavelengths, a multiplexer wavelength-division multiplexing the light output from the light source unit, a polarization beam splitter splitting the light of multiple wavelength components output from the multiplexer according to specific polarization components, phase modulators phase-modulating signals of a first polarization component and a second polarization component split by the polarization beam splitter onto a sine wave having a frequency and amplitude, a radio frequency (RF) signal generator generating the sine wave, a RF signal distributor distributing the generated RF signal, amplifiers amplifying the distributed RF signals, and a polarization beam combiner combining the lights phase-modulated by the respective phase modulators and providing the combined light as a seed light output. | 06-24-2010 |
20100166423 | METHOD, DEVICE, AND SYSTEM FOR POLARIZATION DIVISION MULTIPLEXING AND DEMULTIPLEXING - A method, device, and system for polarization division multiplexing (PDM) and polarization division demultiplexing are provided in the field of communication and transmission. The device for polarization division demultiplexing includes a polarization controller (PC), a polarization beam splitter (PBS), a detection control module, an optoelectronic receiver | 07-01-2010 |
20100178056 | Multi-wavelength coherent receiver with a shared optical hybrid and a multi-wavelength Local Oscillator - An exemplary apparatus for digital coherent detection of a multi-wavelength signal includes a polarization-diversity optical hybrid, at least four Wavelength De-Multiplexing (W-DMUX) filters, 4M detectors, and 4M analog-to-digital converters (ADCs), with M an integer greater than one. The hybrid has a first input for receiving a multi-wavelength signal including M sub-channels at different wavelengths, and a second input for receiving a reference light source including M continuous-wave references at different wavelengths that approximates center wavelengths of the M sub-channels. The hybrid has at least four outputs. A W-DMUX input for each W-DMUX filter is provided a corresponding one of the hybrid outputs, and each W-DMUX filter provides M filtered optical channel outputs. Each detector converts at least one of the filtered channel outputs into a corresponding electrical signal. Each ADC converts one of the electrical signals into a corresponding digital signal. The corresponding digital signals represent the M sub-channels. | 07-15-2010 |
20100189437 | Optical receiver and optical reception method compatible with differential quadrature phase shift keying - In an optical receiver according to the present invention, an input signal light subjected to the differential quadrature phase shift keying (DQPSK) is incident on a PANDA type fiber in a linearly polarized state by 45°, so that a delay time difference corresponding to one symbol is generated between orthogonal polarization components in the DQPSK signal light, and then, the signal light is branched by a half mirror into two, to be sent to first and second paths respectively, thereby giving, by a ¼ wave plate disposed on one of the paths, a relative birefringent amount difference of π/2 between the lights propagated through the respective paths. Then, each of the lights propagated through the first and second paths is separated into two orthogonal polarization components by a polarization beam splitter, and the respective polarization components are received by a differential reception circuit so that in-phase components and quadrature components in the DQPSK signal are demodulated. Thus, a small sized and low cost optical receiver capable of stably demodulating the DQPSK signal is provided. | 07-29-2010 |
20100189438 | POLARIZATION MULTIPLEXING OPTICAL RECEIVER AND POLARIZATION MULTIPLEXING OPTICAL TRANSMISSION SYSTEM - A polarization multiplexing optical receiver includes a polarization controller configured to control a polarization state of a polarization multiplexed optical signal; a polarization splitter configured to split the polarization multiplexed optical signal for which the polarization state is controlled by the polarization controller into a first polarization signal and a second polarization signal; a first detector configured to detect an optical power of the first polarization signal and output a first optical power signal representing the optical power of the first polarization signal; a second detector configured to detect an optical power of the second polarization signal and output a second optical power signal representing the optical power of the second polarization signal; and a controller configured to control the polarization controller on the basis of the first optical power signal and the second optical power signal. | 07-29-2010 |
20100196008 | METHODS AND APPARATUS FOR RECOVERING FIRST AND SECOND TRANSMITTED OPTICAL WAVES FROM A POLARIZATION MULTIPLEXED OPTICAL WAVE - First and second transmitted optical waves having orthogonal polarization states are combined in a polarization multiplexed optical wave. At an optical receiver, an electrical field of the polarization multiplexed optical wave is measured. A plurality of polarization states of the polarization multiplexed optical wave is determined from the measured electrical field. From the plurality of polarization states, a transform that aligns the orthogonal polarization states of the first and second transmitted optical waves with respect to principal axes of the optical receiver is estimated. The first and second transmitted optical waves are recovered by applying the transform to one of i) the polarization multiplexed optical wave and ii) the measured electrical field of the polarization multiplexed optical wave. | 08-05-2010 |
20100196009 | POLARIZATION INDEPENDENT FREQUENCY DOMAIN EQUALIZATION (FDE) FOR CHROMATIC DISPERSION (CD) COMPENSATION IN POLMUX COHERENT SYSTEMS - A method for the polarization independent frequency domain equalization (FDE) chromatic dispersion compensation on polarization multiplexing (POLMUX) coherent systems. Operationally, time domain signals are converted to frequency domain signals such that time domain convolution can be done as simple multiplications in the frequency domain. These frequency domain signals then converted back to time domain for subsequent use. The input signal size and FFT size are advantageously designed so that the output signals can be continuous with some overlap between two successive frames. | 08-05-2010 |
20100239254 | Compensation of Transmission Impairments in Polarization Multiplexed Systems - Systems and methods of compensating for transmission impairment are disclosed. One such method includes receiving a polarization-division multiplexed optical signal which has been distorted in the physical domain by an optical transmission channel, and propagating the distorted polarization-division multiplexed optical signal backward in the electronic domain in a corresponding virtual optical transmission channel. | 09-23-2010 |
20100266282 | Parallel Digital Coherent Detection Using Symmetrical Optical Interleaver and Direct Optical Down Conversion - A method includes modulating lightwaves to provide first and second OFDM signal sidebands at a first polarization direction and first and second OFDM signal sidebands at a second polarization direction, and combining sidebands that are oppositely positioned and joined from the first and second OFDM signal sidebands at each polarization direction to provide a polarization multiplexing OFDM signal. | 10-21-2010 |
20100284693 | ENHANCED SMF PASSIVE OPTICAL NETWORKS USING POLARIZATION BEAMFORMING - The new invention relates to a novel high-performance Passive Optical Network (PON) upgrade architecture, based on adapting Multiple Input, Multiple Output (MIMO) beamforming techniques to polarization multiplexing. | 11-11-2010 |
20100303462 | OPTICAL DETECTION DEVICE IN WDM-PON AND METHOD FOR SAME - A optical detection apparatus includes: an optical splitting unit configured to split a seed lightwave and split upward signal light generated by an optical network unit, based on the seed lightwave; a first control unit configured to control polarizations of the split seed lightwaves based on a first electrical signal; a second control unit configured to control phases of the split seed lightwaves based on a second electrical signal; an optical coupling and signal conversion unit configured to couple the seed lightwaves, of which the polarization and phase are controlled, and the split upward signal lights, convert the coupled optical signals into the first and second electrical signals, and transfer the first and second electrical signals to the first and second control units, respectively; and a signal detection unit. | 12-02-2010 |
20100322627 | DEPOLARISED WDM SOURCE - A device and method for depolarising the total field of a wavelength division multiplexed (WDM) signal is provided. A polarisation maintaining multiplexor combines a plurality of optical signals to form a polarised multiplexed signal. The multiplexed signal is then passed through a differential group delay (DGD) element adapted to modify the polarisation state of one or more optical source signals within the multiplexed signal and thereby to at least partially depolarise the multiplexed signal. | 12-23-2010 |
20100322628 | COHERENT OPTICAL RECEIVER - A coherent optical receiver circuit is disclosed in which various components of the optical receiver may be provided or integrated, in one example, on a common substrate. Further integration is achieved by incorporating various optical demultiplexer designs that are relatively compact and conserve space on the surface of the substrate. The optical receiver circuit may be used to demultiplex quadrature phase shift keying (QPSK) optical signals. | 12-23-2010 |
20100322629 | POLARIZATION BEAM SPLITTER - Consistent with the present disclosure, a polarization multiplexed optical signal having optical signals with both TE and TM polarizations is supplied to an input of a polarization beam splitter (PBS). The PBS includes a first output that supplies TE polarized optical signals and a second output supplies TM polarized optical signals. A first polarizer is coupled to the second output of the PBS to pass the TM polarized optical signals, while rejecting light having other polarizations, such as the TE polarization. A rotator then rotates the light output from the first polarizer, so that such light has a TE polarization. A second polarizer is coupled to the rotator to filter light having a polarization other than the TE polarization. In addition, a third polarizer is coupled to the first output of the PBS in order to filter or block any TM light, for example, that may be output from the PBS with the TE polarized signal. Accordingly, the optical signals in the polarization multiplexed optical signal are effectively filtered, and some are rotated so that each has the same, e.g., TE polarization. Moreover, each optical signal is substantially free from light having extraneous polarizations and may be supplied to an optical hybrid circuit. Data carried by such optical signals may thus be reliably recovered. | 12-23-2010 |
20100322630 | OPTICAL TRANSMISSION APPARATUS AND METHOD - An optical transmission apparatus including a transmitting OTL processor to rearrange a data string stored in a frame into a plurality of logical lanes, and set a lane ID used to identify in which logical lane a beginning of the data string is arranged among the plurality of logical lanes in a non-scramble area in an overhead of the frame, and a receiving OTL processor to respectively identify the lane IDs included in the data string in the respective physical lanes rearranged, determine a generation state of a bit inversion and a lane replacement for each physical lane, compensate the bit inversion and the lane replacement so that the data string in the respective physical lanes becomes same state as the data string in the respective logical lanes, based on the identified result, and rearrange the compensated data string in the respective logical lanes so as to regenerate the frame. | 12-23-2010 |
20100322631 | Optical receiver integrated on a substrate - A coherent optical receiver circuit is disclosed in which various components of the optical receiver may be provided or integrated, in one example, on a common substrate. Further integration is achieved by incorporating various optical demultiplexer designs that are relatively compact and conserve space on the surface of the substrate. The optical receiver circuit may be used to demultiplex quadrature phase shift keying (QPSK) optical signals. | 12-23-2010 |
20100329677 | Symbol Timing Recovery in Polarization Division Multiplexed Coherent Optical Transmission System - A method, apparatus and system for providing clock and data recovery in a receiver for receiving a high speed coherent polarization division multiplexed optical signal using a digital signal processing block including a spectral domain spatial combiner are provided. | 12-30-2010 |
20110033184 | Side Band Pilot Tone for Digital Signal Processing in Polarization Multiplexed Coherent Optical Communication System - A method comprising generating a plurality of first symbols that correspond to a side band pilot tone (SBPT) signal for a plurality of data streams, mapping the first symbols into a plurality of second symbols that correspond to a plurality of signal components of the polarization multiplexed (PM) optical signal, and transmitting the second symbols in a plurality of data blocks of a PM optical signal. An apparatus comprising at least one processor coupled to a memory and configured to obtain a data block that comprises a plurality of SBPTs in a received PM optical signal, estimate a set of values for a carrier frequency and a polarization state, update a tap weight of a master equalizer based on the estimated set of values, and update a plurality of slave equalizers based on the updated tap weight of the master equalizer. | 02-10-2011 |
20110038631 | COHERENT RECEIVER HAVING AN INTERLEAVE-CHIRPED ARRAYED WAVEGUIDE GRATING - An optical coherent detector that employs an interleave-chirped arrayed waveguide grating (AWG). The AWG has a periodic chirp pattern that enables the AWG to function as an optical 90-degree hybrid. If the AWG is implemented using a birefringent material, then the AWG can also function as a polarization demultiplexer. In one embodiment, the AWG is designed to simultaneously function as a wavelength demultiplexer, a polarization demultiplexer for each wavelength-division-multiplexed (WDM) signal component, and a 90-degree hybrid for each polarization-division-multiplexed component of each WDM signal component. | 02-17-2011 |
20110044689 | METHOD AND SYSTEM FOR CROSS-PHASE-MODULATION NOISE REDUCED TRANSMISSION IN HYBRID NETWORKS - A system for cross-phase-modulation-noise reduced transmission in hybrid networks includes a first, second, and third set of optical transmitters. The first set of optical transmitters transmits a set of ten gigabit per second signals. The second set of optical transmitters transmits a set of forty gigabit per second signals. The third set of optical transmitters transmits a set of one hundred gigabit per second signals. On a wavelength spectrum, the set of 10 G signals is immediately adjacent to the set of 100 G signals, and the set of 100 G signals is immediately adjacent to the set of 40 G signals. The set of 10 G signals and the set of 100 G signals are not separated by a guard band. In addition, the set of 100 G signals and the set of 40 G signals are also not separated by a guard band. | 02-24-2011 |
20110076019 | SYSTEM FOR GENERATING OPTICAL RZ SIGNALS BASED ON ELECTRICAL RZ SIGNALS - Consistent with the present disclosure, polarized optical signals having the same wavelength are modulated in response to ERZ drive signals, to thereby yield corresponding RZ optical signals. Each of the polarized RZ optical signals includes a plurality of RZ transitions wherein the power of the optical signal returns to zero or a minimal power between bits or symbols. The phase or timing of the ERZ drive signals, however, is controlled, so that the RZ transitions in one polarized optical signal remain interleaved with the RZ transitions of the other polarized optical signal. Alternatively, the RZ transitions of the two polarized optical signals may be controlled so that the two are temporally aligned with one another. Thus, the timing of the RZ transitions of one polarized optical signal relative to the other polarized optical signal may be adjusted to optimize system performance. | 03-31-2011 |
20110076020 | POWER CONTROL OF OPTICAL SIGNALS HAVING DIFFERENT POLARIZATIONS - Consistent with an aspect of the present disclosure, an optical communication apparatus is provided that transmits a WDM signal including a plurality of optical channels, wherein each channel has a corresponding one of a plurality of wavelengths. Each of the plurality of optical channels includes optical signals having first (e.g., TE) and second (e.g., TM) polarizations. In one example, each polarized optical signal is modulated in accordance with an identifying tone. The optical channels are combined onto a waveguide, and an optical tap connected or coupled to the waveguide supplies a portion of the WDM signal including a composite of the optical channels to a photodiode. The aggregate power received by the photodiode includes the power associated with each optical channel, and the power of each channel is the sum of the powers of individual polarized optical signals within that channel. The photodiode converts the received WDM portion including the polarized optical signal portions into corresponding electrical signals. A processor circuit demodulates the electrical signals, identifies the tones, and determines a modulation depth for each tone. Based on the modulation depth, a ratio of the optical powers of one polarized optical signal to another can be calculated, and the optical powers of one or both of the polarized optical signals in each channel can be adjusted so that the optical power ratio has a desired value, e.g., a value substantially equal to one. Thus, one tap and one photodiode may be provided to monitor each polarized optical signal within each WDM channel, thereby reducing costs and yielding a simpler system design. | 03-31-2011 |
20110076021 | OPTICAL RECEIVER SYSTEMS AND METHODS FOR POLARIZATION DEMULTIPLEXING, PMD COMPENSATION, AND DXPSK DEMODULATION - A simplified optical receiver architecture capable of tracking and demultiplexing polarization-multiplexed signals, dynamically compensating for PMD using a variety of polarization controller technologies, and reducing the number of delay line demodulators by two for both DPSK and DQPSK modulation is illustrated. Once polarization is stabilized at the first stage of the cascaded system of the present invention, subsequent stages can be simplified and cost reduced. | 03-31-2011 |
20110081150 | Clock Recovery Method for Polarization Multiplexed Coherent Optical Communications - An apparatus comprising a plurality of receivers each configured to receive a plurality of polarized signals, a voltage control oscillator (VCO) coupled to the receivers and configured to control timing and sampling frequency of the polarized signals, and a signal processing component coupled to the receivers and configured to update a plurality of weighted linear factors, wherein the polarized signals and the weighted linear factors are used to obtain a combined signal, and wherein the weighted linear factors are updated using a real part or an imaginary part of the combined signal. Included is a method comprising using a linear factor to combine a plurality of polarized optical signals to provide time recovery information, and updating the linear factor using a combination of the polarized optical signals. | 04-07-2011 |
20110085802 | Polarization-multiplexed optical transmission - In optical signal transmission, multiple sets of optical signals which contain data and are associated with at least two polarization states are multiplexed using a single arrayed waveguide grating (AWG). The resulting multiplexed signals are then polarization-multiplexed for transmission. In one embodiment, the AWG is provisioned in a unidirectional mode to multiplex the multiple sets of optical signals. In another embodiment, the AWG is provisioned in a bidirectional mode to multiplex the multiple sets of optical signals. | 04-14-2011 |
20110097085 | OPTICAL TRANSMITTER, OPTICAL TRANSMITTER AND RECEIVER SYSTEM, OPTICAL TRANSMITTING METHOD AND OPTICAL TRANSMITTING AND RECEIVING METHOD - An optical transmitter includes: a pre-compensator calculating an electrical field of an optical signal subjected to an electronic pre-compensation with respect to an input digital signal; a parallelizer parallelizing the electrical field of the optical signal calculated by the pre-compensator; a plurality of optical modulators modulating an optical signal based on each of parallelized electrical fields of optical signals; and a time-division multiplexer time-division-multiplexing an optical signal output from the plurality of the optical modulators. | 04-28-2011 |
20110103795 | SOFT DECODING OF DATA IN A COHERENT OPTICAL RECEIVER - In a coherent optical receiver receiving a polarization multiplexed optical signal through an optical communications network, a method of compensating noise due to polarization dependent loss (PDL). A Least Mean Squares (LMS) compensation block processes sample streams of the received optical signal to generate symbol estimates of symbols modulated onto each transmitted polarization of the optical signal. A decorrelation block de-correlates noise in the respective symbol estimates of each transmitted polarization and generating a set of decorrelated coordinate signals. A maximum likelihood estimator soft decodes the de-correlated coordinate signals generated by the decorrelation block. | 05-05-2011 |
20110110663 | METHOD, DEVICE, AND SYSTEM FOR REALIZING POLARIZATION MODE DISPERSION COMPENSATION - A method, device, system for realizing polarization mode dispersion (PMD) compensation are provided. The method for realizing PMD compensation includes: de-multiplexing a polarization-multiplexed optical signal, to obtain a first polarization light and a second polarization light; and joint-equalizing the first polarization light and the second polarization light, to obtain a first equalization signal and a second equalization signal. Since the polarization-multiplexed optical signal is de-multiplexed and then joint-equalized, not only the intra-channel symbol interference but also the inter-channel symbol interference during transmission of the polarization-multiplexed optical signal is eliminated, so as to realize the PMD compensation. | 05-12-2011 |
20110142449 | Method And Apparatus For Polarization-Division-Multiplexed Optical Coherent Receivers - The singularity problem of the constant modulus algorithm (CMA) equalizer may be overcome by implementing the CMA equalizer as a two-stage equalizer, with the first stage being a modified version of a CMA equalizer and the second stage being a conventional CMA equalizer. The first stage may be made up of four sub-equalizers, of which only two of the sub-equalizers are independent, i.e., uncorrelated to each other. This first stage equalizer may compensate for PMD. The second stage equalizer is a conventional CMA equalizer made up of four sub-equalizers that are adjusted independently. This second stage equalizer may compensate for polarization-dependent loss (PDL) and any residual CD that is not fully compensated for by a CD compensator before the two-stage equalizer. Advantageously, as the determinant of the first stage never approaches zero, the singularity problem of a conventional CMA single-stage-only equalizer is avoided by the two-stage equalizer. | 06-16-2011 |
20110150477 | Receiver Algorithms for Coherent Detection of Polarization-Multiplexed Optical Signals - A digital signal processor (DSP) operating within, for example, an optical receiver wherein the DSP processes complex sample streams derived from a received modulated optical signal, the DSP configured to perform a method comprising: processing at least one block of symbols within a complex symbol stream to define a received constellation having symbols located within decision boundaries; and verifying that the received constellation does not exhibit errors by comparing the received constellation to each of a sequence of reference constellations having corresponding phase shifts within an angular ambiguity range of the first constellation. | 06-23-2011 |
20110150478 | Receiver Algorithms for Coherent Detection of Polarization-Multiplexed Optical Signals - A digital signal processor (DSP) operating within, for example, an optical receiver wherein the DSP processes complex sample streams derived from a received digitally modulated optical signal, the DSP configured to perform a method comprising: using a filter adaptation algorithm (FAA), processing digitized complex sample streams for each of a sequence of unitary matrix different starting conditions associated with the FAA to establish a converged FAA. | 06-23-2011 |
20110150479 | Multi-Level Polarization Multi-Level Phase Modulator - An apparatus for use with an optical computation system may comprise a monolithic device with no free space optical components and may include a phase modulator and a polarization modulator. The phase modulator may be configured to receive a beam of light and two digital data streams and operable to modulate the phase of the beam of light to at least four phase states, the at least four phase states representing the two digital data streams. The polarization modulator may be configured to receive two additional digital data streams and the modulated beam of light from the phase modulator and operable to modulate the polarization of the beam of light to at least four polarization states, the at least four polarization states representing the two additional digital data streams. | 06-23-2011 |
20110170869 | POLARIZATION MULTIPLEXING TRANSMITTER AND TRANSMISSION SYSTEM - A polarization multiplexing transmitter which generates polarization-multiplexed signals which are arbitrarily polarization-scrambled at high speed, without adding a polarization modulator and a polarization scrambler. In the transmitter, an orthogonally polarized signal generator includes two optical modulators which modulate the electric fields of optical signals and generate two optical signals with mutually orthogonal polarized waves. The transmitter includes electric field mappers which convert two data strings into electric field signals, polarization mappers which give different polarized waves to the two signals, polarization rotators which rotate the polarized waves of the signals uniformly, a polarization multiplexer which multiplexes the two polarization-rotated signals, a polarization demultiplexer which demultiplexes the multiplexed signal into polarized wave components of optical signals generated by the orthogonally polarized signal generator, and a driver. The optical modulators are driven to make the two demultiplexed electric field signals consistent with the electric fields of optical signals modulated by the modulators. | 07-14-2011 |
20110170870 | Method and Device for Stabilizing the State of Polarization of a Polarization Multiplexed Optical Radiation - A device and method for stabilizing the state of polarization of polarization multiplexed optical radiation including an identified channel is disclosed. The device and method comprise providing to the polarization multiplexed optical radiation a first controllable polarization transformation to generate a first transformed optical radiation; detecting a first state of polarization of a first polarized portion with respect to a first polarization parameter; controlling the first controllable polarization transformation so that the first polarization parameter has a predetermined value independent of a polarization state of the polarization multiplexed optical radiation; providing to the first transformed optical radiation a second controllable polarization transformation to generate a second transformed optical radiation; detecting a second state of polarization of a second polarized portion; and controlling the second controllable polarization transformation so that the second state of polarization has a predefined value. | 07-14-2011 |
20110182582 | JOINT SAMPLE RATE CONVERSION AND CD COMPENSATION IN FREQUENCY DOMAIN FOR COHERENT POLMUX - A combined CD compensation and sample rate conversion method performed in the frequency domain. | 07-28-2011 |
20110194855 | SUPERIMPOSED TRAINING AND DIGITAL FILTERING COHERENT OPTICAL RECEIVERS - In a polarization-multiplexing optical communications system, a method and system for coherent reception of polarization-multiplexed optical communications. Training and data sequences are recovered from a plurality of orthogonally polarized signals, such that training and data sequences may be used on a single channel without loss of spectral efficiency. This is accomplished by estimating a channel response for each orthogonally polarized signal based on the mean of the signal and distinguishing between a data sequence and a training sequence in each orthogonally polarized signal. Such distinguishing is accomplished according to an iterative linear minimum mean-square equalization based on the respective channel response estimate. | 08-11-2011 |
20110206375 | METHOD, DEVICE, AND SYSTEM FOR OPTICAL POLARIZATION DIVISION MULTIPLEXING OF OPTICAL CARRIER - The method includes: splitting an optical carrier into two or more sets of optical sub-carriers at a receiving end; respectively performing optical PDM on each set of the optical sub-carriers to obtain two sets of to-be-demodulated optical signals; and extracting a part of signals from each set of the to-be-demodulated signals to calculate features characterizing polarization states, controlling feedback signals according to the features, and correspondingly adjusting a polarization state of each set of the optical sub-carriers. With the device combining optical division into two or more sets of sub-carriers with optical PDM, an optical carrier signal can be split in an optical modulation format into four or more sets of signals for processing, and delay interference can be performed directly on an optical wave by using Differential Quadrature Phase Shifted Keying (DQPSK) demodulators to obtain by detection output signals. | 08-25-2011 |
20110211835 | System and Method for Mitigating Polarization Hole Burning - A system for mitigating the effects of polarization hole burning in an optical communication system. The system includes an optical input signal comprising one or more traffic channels, a measurement module configured to check for the existence of ghost channels around the traffic channels, and a ghost channel generation module configured to generate a ghost channel around the traffic channels from amplified spontaneous emission noise of the optical input signal. | 09-01-2011 |
20110211836 | System and Method for Optimizing the Selection of Ghost Channels in Mitigating Polarization Hole Burning - A system and method for optimizing the selection of ghost channels to mitigate the effects of polarization hole burning in a node of an optical communication system including identifying an optical communication channel in the node for use as a ghost channel, identifying a first set of degrees carrying the optical communication channel within the node, identifying a second set of degrees within the first set of degrees, the second set containing the degrees with the optical communication channel being a valid channel, identifying a third set of degrees within the first set of degrees, the third set containing degrees with the optical communication channel being sufficiently powerful, and selecting a first degree to source the ghost channel from the first set of degrees based at least on the second set of degrees and the third set of degrees. | 09-01-2011 |
20110217043 | ITERATIVE CARRIER-PHASE ESTIMATION AND DATA RECOVERY FOR COHERENT OPTICAL RECEIVERS - In one embodiment, a coherent optical receiver has an optical detector coupled to a digital processor. The optical detector mixes a received modulated optical signal with a local-oscillator signal to produce a digital measure of the modulated optical signal. The digital processor processes the digital measure using a primary carrier- and data-recovery (CDR) stage and one or more secondary CDR stages serially connected to one another. The processing performed in each secondary CDR stage is decision-directed and uses the symbol estimate generated by the preceding CDR stage to obtain a respective estimate of the carrier-phase offset and a respective symbol estimate. Since each subsequent CDR stage typically improves the accuracies of its estimates compared to those of the preceding CDR stage(s), the receiver has a lower bit-error rate than a receiver employing a single CDR stage. | 09-08-2011 |
20110222853 | POLARIZED-WAVE-MULTIPLEXING OPTICAL TRANSMITTER AND CONTROL METHOD OF POLARIZED-WAVE-MULTIPLEXED OPTICAL SIGNAL - A polarized-wave-multiplexing optical transmitter including: an optical combiner generating a polarized-wave-multiplexed optical signal by polarized-wave-multiplexing a first optical modulation signal and a second optical modulation signal; an optical power fluctuation portion fluctuating optical power of the first optical modulation signal and the second optical modulation signal periodically; a total-optical-power detection portion detecting fluctuation amount of total optical power of the polarized-wave-multiplexed optical signal; and an optical power controller reducing an optical power difference between the first optical modulation signal and the second optical modulation signal based on detection result of the total-optical-power detection portion. | 09-15-2011 |
20110229137 | Tunable Receiver - Embodiments for optical communication are provided in which tunable receiver selects and demodulates a first channel of a WDM signal. An example receiver includes a tunable local oscillator for generating a local oscillator signal approximately centered at a first channel wavelength. An optical hybrid of the receiver receives at a first input a wavelength-division-multiplexed (WDM) signal with a M-ary modulation scheme, wherein M is an integer greater than 2, and at a second input the local oscillator signal. A plurality of detectors detect in-phase and quadrature components of the first channel wavelength output of the optical hybrid, which are digitizing by a plurality of analog-to-digital converters. A digital signal processor processes the digitized in-phase and quadrature components in order to recover data carried by the first channel of the WDM signal. | 09-22-2011 |
20110243561 | FILTER, COHERENT RECEIVER DEVICE AND COHERENT RECEIVING METHOD - The present invention relates to filter, coherent receiver device and coherent receiving method. The filter is used for converting a partial response signal into a full response signal, wherein the filter uses the following transfer function H | 10-06-2011 |
20110243562 | METHOD AND APPARATUS FOR INTEGRATED WAVEGUIDE TRANSMIT-RECEIVE ISOLATION, FILTERING, AND CIRCULAR POLARIZATION - An radio is provided for transmit-receive isolation filtering and circular polarization (INTRIFPWA) that are sealed within a metal housing of a transmitter, which can be used in microwave communication systems, including satellite based communications systems and terrestrial based microwave communication systems. | 10-06-2011 |
20110249971 | Polarization fluctuation compensation device and optical communication system - A polarization fluctuation compensation device, when WDM light received by, for example, an optical reception device includes a polarization scrambled optical signal and a non-polarization scrambled optical signal, collects information related to whether optical signals having respective wavelengths are polarization scrambled, obtains a target value of control parameters which are different from each other, according to the speed of polarization fluctuations in the non-polarization scrambled optical signal based on the collected information, and performs reception processing of the non-polarization scrambled optical signal by using a control parameter set as the target value. As a result, an influence of fast polarization fluctuations generated resulting from an interaction between optical signals having respective wavelengths can be reliably compensated for, thereby enabling to realize excellent reception characteristics. | 10-13-2011 |
20110255870 | OPTICAL TRANSCEIVERS FOR USE IN FIBER OPTIC COMMUNICATION NETWORKS - The present disclosure provides a polarization multiplexed transceiver, including: a transmitter; a receiver; circuitry within the transmitter configured to insert pilot tones as a reference state of polarization for a polarization multiplexed signal; and circuitry within the receiver configured to de-multiplex the polarization multiplexed signal using the pilot tones. The transmitted signal is constructed in such a manner as to facilitate the division of the receiver processing between the analog and digital domains such that the implementation may be simultaneously both highly spectrally efficient and power efficient. | 10-20-2011 |
20110274429 | METHOD AND APPARATUS FOR PHASE SHIFT KEYED OPTICAL COMMUNICATIONS - A burst-mode differential phase shift keying (DPSK) communications system according to an embodiment of the present invention enables practical, power-efficient, multi-rate communications between an optical transmitter and receiver. An embodiment of the system utilizes a single interferometer in the receiver with a relative path delay that is matched to the DPSK symbol rate of the link. DPSK symbols are transmitted in bursts, and the data rate may be varied by changing the ratio of the burst-on time to the burst-off time. This approach offers a number of advantages over conventional DPSK implementations, including near-optimum photon efficiency over a wide range of data rates, simplified multi-rate transceiver implementation, and relaxed transmit laser line-width requirements at low data rates. | 11-10-2011 |
20110274430 | Optical transmission system - An optical transmission system, where in an optical transmitter a detection bit having a specific pattern set according to the number of bits to be transmitted within one symbol time, is imparted with respect to a transmission signal in which transmission information has been encoded according to a preset format, and an optical signal generated by modulating light according to the transmission signal is transmitted to a transmission line. In an optical receiver, logic inversion or bit swap of received data is detected and compensated by using the detection bit included in the received signal, a decoding process of the compensated received signal is executed. As a result, when an optical signal capable of transmitting multi-bit information within one symbol time is transferred, it is possible to realize excellent transmission characteristics, by reliably compensating an error in received data caused by the modulation format or the multiplex system of the optical signal. | 11-10-2011 |
20110293275 | Polarization Control in a Photonic Integrated Circuit - The present invention provides a system, apparatus and method to maintain the polarization state of an optical signal propagating within a photonic integrated circuit, or from a first photonic integrated circuit to a second photonic integrated circuit. According to various embodiments of the invention, an optical circuit is provided which includes an optical coupler configured to accept a first optical signal on a first input and a second optical signal on a second input, the second optical signal having a polarization state. The optical coupler may combine the first and second optical signals into an optical output signal. A principle axis of a first end of an optical fiber is may be configured to align with the polarization state of the second optical signal, such that a polarization maintaining connection is established. The polarization state may be a TM polarization state, a TE polarization state, or another polarization state. The optical circuit may include birefringent structures, such as birefringent waveguides and birefringent wavelength selective couplers, to further maintain the polarization of optical signals propagating through the photonic integrated circuits. | 12-01-2011 |
20110293276 | OPTICAL TRANSMITTER AND METHOD FOR CONTROLLING THE SAME - An optical transmitter includes: a first modulator that modulates a first optical signal with a first data signal; a second modulator that modulates a second optical signal with a second data signal; a multiplexer that multiplexes the first optical signal and the modulated second optical signal to output a multiplexed signal; a phase difference data generator that generates a phase difference signal corresponding to a phase difference between the modulated first optical signal and the modulated second optical signal from the multiplexed signal; and a controller that controls the phase difference between the modulated first optical signal and the modulated second optical signal based on the phase difference signal. | 12-01-2011 |
20110299852 | OPTICAL TRANSMISSION AND RECEPTION SYSTEM, OPTICAL TRANSMITTING AND RECEIVING APPARATUS, AND OPTICAL TRANSMISSION AND RECEPTION METHOD - An optical transmission and reception system in which a plurality of tributary signals are converted into multilevel modulated light for transmission and reception. An apparatus for transmitting multilevel modulated light includes: FECs which perform error correction processing including addition of a tributary identifier; and a GEAR BOX which performs rate conversion on the processed signals. An apparatus for receiving multilevel modulated light includes: a 20G DQPSK REC which separates received multilevel modulated light into received tributary signals and outputs the signals to respective output systems; the GEAR BOX which performs rate conversion on the received tributary signals; the FECs which extract tributary identifiers from the received tributary signals; a TIM which compares tributary identifiers defined for the respective output systems in advance with the tributary identifies extracted; and a tributary selector which gives an instruction to change correspondence between the received tributary signals and the output systems if the result of comparison is a mismatch. | 12-08-2011 |
20110305457 | Optical Multi-Level Transmission System - Provided is an optical multilevel transmission system, comprising at least one optical multilevel transmitter for transmitting an optical multilevel signal obtained and an optical multilevel receiver for receiving the optical multilevel signal. The received optical multilevel signal has a larger noise in an angular direction than in a radial direction. The optical multilevel receiver sets, in a symbol decision of the received optical multilevel signal demodulated on the complex plane, for positions of all or some of ideal signal points, a width in the angular direction of a decision area, to which each of the ideal signal points belongs and which is measured along a circumference of a circle centered at an origin and passing through a center of the each of the ideal signal points, larger than a width in the angular direction of a decision area defined based on a Euclidean distance. | 12-15-2011 |
20120008950 | Orthogonally-Combining Interleaving Filter Multiplexer and Systems and Methods Using Same - In general, a wavelength division multiplexed (WDM) communication system simultaneously pre-filters and combines groups of wavelengths with orthogonal polarizations to provide a pre-filtered, pair-wise orthogonal aggregate WDM optical signal. In particular, an orthogonally-combining interleaving filter multiplexer provides substantially orthogonal polarizations for odd and even channel wavelengths and simultaneously pre-filters and combines the orthogonally polarized odd and even channel wavelengths using interleaver optics. The orthogonal polarizations may be provided by orientation of PM input fibers or by a polarization rotator in the orthogonally-combining interleaving filter multiplexer. | 01-12-2012 |
20120008951 | DEMODULATOR AND OPTICAL TRANSCEIVER - In a free space optical system type demodulator of a phase shift keying signal, if a half beam splitter is used as a non-polarizing optical branching unit that is used when generating beams corresponding to I and Q channels or when multiplexing an interference light, control of a power branching ratio is difficult, and it is necessary to suppress phase shifts that are different depending on a polarization state of an input state, and thereby the demodulator becomes high cost. Moreover, since directions of branched lights are different, it is difficult to suppress a skew of the demodulator. In the present invention, the non-polarizing optical branching unit that is used when generating the beams corresponding to the I and Q channels and when multiplexing the interference light is realized using polarization rotating elements and polarization separating elements. Moreover, branched beams are substantially aligned. | 01-12-2012 |
20120008952 | Method and Apparatus for Carrier Phase Estimation and Correction in a Coherent Optical System - An apparatus comprising a nonlinear lookup unit (NL-LUU) configured to add a phase shift to a signal sample to compensate for pattern dependent phase distortion, and one or more first phase adjustment units coupled to NL-LUU and configured to remove from the signal sample a nonlinear phase error from the NL-LUU, wherein the signal sample corresponds to a received signal polarization component of a polarization multiplexed (PM) coherent signal in a PM coherent optical system. | 01-12-2012 |
20120014695 | Digital Light Path Labeling System with Dual Polarization Quaternary Phase-shift Keying Modulation - A method and system for encoding and determining labels in a Dual Polarization (DP) Quaternary Phase Shift Keying (QPSK) signal is provided. A label frame, signature sequence, and data payload are combined using a complementary constant-weight code encoding (CCWC) encoder, the output of which is deinterleaved and differentially precoded to generate a polarized tributary of a DP-QPSK signal. This encoding can be duplicated for a second tributary of the DP-QPSK signal. The label can be determined using one or more polarizers and corresponding low-speed photodetectors, each applied to a copy of the DP-QPSK signal. The strongest output of the photodetectors is then used to determine the label. Alternatively, the DP-QPSK signal can be viewed as having XI, XQ, PH, and PV tributaries. These tributaries can then be translated into XI, XQ, YI, and YQ tributaries are encoded into a standard DP-QPSK signal. | 01-19-2012 |
20120020665 | Optical signal processor - A probe light source produces probe light having a second wavelength different from a first wavelength of signal light. To a light modulator, the probe light and signal light produced from the probe light source are supplied. The light modulator multiplexes the probe light and signal light produced from the probe light source, and supplies it to a nonlinear optical medium. Further, the light modulator modulates the probe light by an intensity change of the signal light in the nonlinear optical medium, and outputs modulated light having the second wavelength based on the data of the signal light. | 01-26-2012 |
20120027410 | METHOD, DEVICE AND SYSTEM FOR GENERATING AND RECEIVING A PHASE POLARIZATION MODULATED SIGNAL - In the field of communications transmission, a method, a device, and a system for generating and receiving a phase polarization modulated signal are disclosed. The device for generating the phase polarization modulated signal includes: a Laser Diode (LD), a time division demultiplexer, a phase precoding module, a phase modulating module, a polarization precoding module and a polarization modulating module. The device for receiving the phase polarization modulated signal includes: an optical splitter, a polarizer, a phase demodulating and receiving unit, a Polarization Beam Splitter (PBS), a balanced receiver, a power divider, an exclusive OR, a delayer and a data interface processing unit. Therefore, problems in the prior art that a Differential Quadrature Phase Shift Keying (DQPSK) signal cannot bear and transmit information at a higher rate and that non-linear effect is strong during transmission are solved, and transmission performance of an optical signal is improved. | 02-02-2012 |
20120039606 | LOW POWER OPTICAL TRANSCEIVER USING ORTHOGONAL POLARIZATION DETECTION TECHNIQUE - A method and apparatus for simultaneous processing of signals impressed on a horizontal polarization of a light wave and on a vertical polarization of the light wave is provided. In one embodiment, a horizontal polarization pilot tone is impressed on a data signal carried by the horizontal polarization and a vertical polarization pilot tone is impressed on a data signal carried by the vertical polarization. A receiver processes the dual-polarized light wave and converts it to an X channel signal and a Y channel signal. The X and Y channel signals are processed in separate channels to recover a phase and frequency offset between them and a local oscillator. The phase and frequency recovered and frequency de-multiplexed signals are further processed to polarization de-multiplex the data signal carried by the horizontal polarization and the data signal carried by the vertical polarization. | 02-16-2012 |
20120039607 | OPTICAL RECEIVER, OPTICAL COMMUNICATION SYSTEM USING THE SAME AND EQUALIZATION METHOD IN THE OPTICAL COMMUNICATION SYSTEM - An optical receiver according to the invention includes a polarization diversity unit receiving a polarization multiplexed optical signal obtained by multiplexing two optical signals having a same frequency band of carrier waves and polarization states orthogonal to each other, and a frequency domain equalization unit receiving signal components parallel to mutually orthogonal polarization axes from the polarization diversity unit, wherein the frequency domain equalization unit includes filters for which filter coefficients thereof are set for compensating degradation of transmission characteristics in one optical signal without polarization multiplexing by means of the frequency domain equalization. | 02-16-2012 |
20120045208 | COHERENT RECEIVER - A coherent receiver | 02-23-2012 |
20120063781 | SYSTEM AND METHOD FOR REDUCING POLARIZATION DEPENDENT LOSS CROSS-TALK EFFECTS - In accordance with the present disclosure a system for reducing polarization dependent loss (PDL) of an optical signal comprises a delay module coupled to one or more PDL inducing network elements of an optical network. The delay module is configured to time interleave a first polarization component with respect to a second polarization component of the optical signal. The time interleaving reduces interference caused by cross-talk components associated with the first and second polarization components and induced by the PDL of the PDL inducing elements. | 03-15-2012 |
20120070149 | COHERENT OPTICAL RECEIVING APPARATUS AND OPTICAL SIGNAL PROCESSING METHOD - Provided is a coherent optical receiving apparatus and an optical signal processing method. The coherent optical receiving apparatus may include an optical hybrid unit to generate an optical signal by combining a first optical signal inputted from an optical transmitting apparatus and a second optical signal inputted from a local oscillator, a polarization demuxer to demultiplex the optical signal outputted from the optical hybridizing unit, a frequency offset compensator to estimate a frequency offset of at least one of even-numbered samples and odd-numbered samples, and to compensate for a frequency offset of the even-numbered samples and a frequency offset of the odd-numbered samples using the at least one estimated frequency offset, and a carver distortion compensator to compensate for phase distortions of the samples for which the compensation for the frequency offset is performed, the phase distortions being generated by the optical transmitting apparatus. | 03-22-2012 |
20120082457 | K-Means Clustered Polyphase Filtering for Sample Rate Conversion in Coherent Polarization Multiplexing Fiber Optic Systems - A method for clustered polyphase filtering input data converted from an optical signal converting input data from a serial form into a parallel form, permutating data symbols from the input data to form K clusters, passing the permutated data to an adder and multiplier for each cluster; and adding output of all K multipliers together to form an output. | 04-05-2012 |
20120087661 | Long Distance Transmission Of Incoherent Optical Signals In An Optical Network - A method and apparatus of transmitting a 10 G non-return to zero (NRZ) optical signal over a long length of single mode fiber between a 10 G NRZ optical source and a 10 G digital coherent receiver is described. A device receives a 10 G NRZ optical signal from the 10 G NRZ optical source, where the 10 G NRZ optical signal has an accumulated dispersion that is greater than a dispersion tolerance of an incoherent 10 G NRZ optical receiver. The device further recovers the 10 G NRZ optical signal using the 10 G digital coherent receiver. | 04-12-2012 |
20120093510 | CORRELATION -CONTROL QPSK TRANSMITTER - An optical transmitter utilizing a multi-level data modulator to produce a PDM-QPSK signal, a one-bit delay interferometer configured to correlate the multi-level data modulated signal and an optical filter configured to combine the correlated multi-level data modulated signal with one or more neighboring signals prior to transmitting over one of a plurality of optical channels. The PDM-QPSK correlated signal is configured to reduce the signal spectrum thereby increasing spectral efficiency of the transmitted signal. | 04-19-2012 |
20120099864 | CHROMATIC DISPERSION VALUE CALCULATING APPARATUS, OPTICAL SIGNAL RECEIVING APPARATUS, OPTICAL SIGNAL TRANSMITTING APPARATUS, AND CHROMATIC DISPERSION VALUE CALCULATION METHOD - In order to compensate for chromatic dispersion caused by optical fiber transmission in a communication system with coherent detection using optical signals, specific frequency band signals are used to enable estimation of a chromatic dispersion value. The chromatic dispersion value calculating apparatus is provided with: a signal distributing circuit which distributes, into a plurality of signal sequences, an electrical digital signal converted from received optical signals of an optical signal transmitted by an optical signal transmitting apparatus, in which a known signal with concentrated frequency components of a plurality of specific frequencies is appended to a signal generated from a transmission data sequence; a plurality of frequency band pass filter circuits, each of which separating only each of a plurality of specific frequency components in which the known signal is included from each of the signal sequences distributed by the signal distributing circuit, and passing each of the specific frequency components therethrough; a plurality of power calculating circuits which are provided so as to correspond respectively to the plurality of frequency band pass filter circuits and which calculate power values of signals output from the corresponding frequency band pass filter circuits; a delay time calculating circuit which detects times at which power has the maximum value or times at which the power exceeds a predetermined threshold value, respectively from signal sequences of the power values output from the plurality of power calculating circuits, and which compares the detected times; and a chromatic dispersion value calculating circuit which calculates a chromatic dispersion value based on a comparison result of the times by the delay time calculating circuit. | 04-26-2012 |
20120106962 | POLARIZATION MULTIPLEXING AND TRANSMITTING APPARATUS - A polarization multiplexing and transmitting apparatus generates polarization multiplexed light by multiplexing modulated signal components that having varying intensities and are in polarization states orthogonal to each other. The polarization multiplexing and transmitting apparatus includes a converting unit that converts light generated by a light source into signal components having a varying intensity synchronized with a clock signal input thereto and a varying intensity inversely synchronized with the clock signal, respectively; a modulating unit that modulates the signal components, respectively; and a polarization adjusting unit that orthogonalizes polarization states of the signal components. | 05-03-2012 |
20120121264 | APPARATUS AND METHOD FOR TRANSMITTING LIGHT, AND APPARATUS AND METHOD FOR RECEIVING LIGHT - An optical transmitting apparatus optically modulates a transmitting signal to transmit the signal to an optical receiving apparatus using a phase of two optical carriers having each wavelength, and an optical receiving apparatus demodulates an optical signal having a modulated phase with intensity modulation to detect a transmitting signal. | 05-17-2012 |
20120134676 | Polarization-Multiplexed Optical Transmission System, Polarization-Multiplexed Optical Transmitter, and Polarization-Multiplexed Optical Receiver - There is a need to prevent two receivers from converging on a state of receiving the same polarization state, fast start receivers, and ensure highly reliable operations. A polarization-multiplexed transmitter previously applies frequency shifts of frequencies +Δf and −Δf to X-polarization and Y-polarization digital information signals to be transmitted. Optical field modulators modulate and polarization-multiplex the signals. As a result, a frequency difference of 2Δf is supplied to X-polarization and Y-polarization components. A polarization diversity coherent optical receiver | 05-31-2012 |
20120141128 | Colorless Dense Wavelength Division Multiplexing Transmitters - A dense wavelength-division-multiplexing (DWDM) system, comprising a plurality of laser transmitters, a wavelength division multiplexer (WDM) optically coupled to the laser transmitters and to an output optical transmission media, a coupler optically coupled to the output optical transmission media, an interferometric filter optically coupled to the coupler but not directly to the output optical transmission media, and a light reflector optically coupled to the interferometric filter and not directly to the output optical transmission media. | 06-07-2012 |
20120155875 | OPTICAL RECEIVER - Disclosed is an optical receiver including: a polarization splitter splitting two polarization components perpendicular to each other from an optical signal to output a first polarization signal and a second polarization signal; a first optical delay splitter and a second optical delay splitter branching each polarization signal to output two branch signals, respectively; a first optical hybrid and a second optical hybrid each outputting four interference signals in which a phase shift increases by each 90° by using the two branch signals; and four photo detectors each outputting a differential signal between two interference signals in which the phase shift is 180° . | 06-21-2012 |
20120155876 | SEED LIGHT MODULE FOR WAVELENGTH DIVISION MULTIPLEXING-PASSIVE OPTICAL NETWORK AND METHOD FOR DRIVING THE SAME - A seed light module for a WDM-PON system is provided. The seed light module includes a reflector configured to reflect a part of seed light that is generated from a light source generator, and an optical attenuator configured to attenuate the intensity of the reflected seed light and provide the attenuated seed light, which corresponds to a signal generated by attenuating the intensity of the reflected seed light, to the light source generator. | 06-21-2012 |
20120177372 | Apparatus And Method For Generating Interleaved Return-To-Zero (IRZ) Polarization-Division Multiplexed (PDM) Signals - Return To Zero (RZ) shaping is performed for a first I/Q modulator whose output corresponds to a first polarization component using a first two digital-to-analog convertors (DACs), each of which is sampled at approximately twice a modulation symbol rate or more and has an output with a first interleaving order that interleaves one of a first pair of intended drive signal patterns and zeros. RZ shaping is also performed for a second I/Q modulator whose output corresponds to a second polarization component using a second two DACs, each sampled at approximately twice the modulation symbol rate or more and having a second interleaving order that interleaves zeros and one of a second pair of intended drive signal patterns, the second interleaving order opposite the first interleaving order. The first polarization and the second polarization may be combined, thereby forming an Interleaved Return To Zero (IRZ) Polarization Division Multiplexed (PDM) signal. | 07-12-2012 |
20120183295 | Polarization Diversity with Portable Devices via Wavefront Muxing Techniques - A novel terrestrial wireless communications technique for terrestrial portable terminals including hand-held mobile devices and fixed wireless instruments, utilizing a spoke-and-hub communications system, having a plurality of individual hubs and/or base-stations all in communications with the portable terminals. The portable terminals and the hubs are assigned to use incompatible polarity formats in terms of circularly polarity (CP) and linearly polarity (LP). In forward links, a signal processed by the LP ground telecommunications hubs is radiated through multiple antennas with various LP polarities to an individual CP user simultaneously. The multiple paths are organized via assignments of a plurality of polarities, frequency slots, and directions by wavefront multiplexing/demultiplexing techniques such that the same communications assets including frequency spectrum may be re-used by other users. The same polarity diversity methods can be extended to peer-to-peer communications. | 07-19-2012 |
20120189306 | MULTI-LASER TRANSMITTER OPTICAL SUBASSEMBLIES FOR OPTOELECTRONIC MODULES - Multi-laser transmitter optical subassemblies (TOSAs) for optoelectronic modules. In one example embodiment, a multi-laser TOSA includes first and second lasers configured to generate first and second optical signals, respectively, a polarization beam combiner (PBC), first and second collimating lenses positioned between the first and second lasers, respectively, and the PBC, a half waveplate positioned between the first laser and the PBC, and a focusing lens. The half waveplate is configured to rotate the polarization of the first optical signal. The PBC is configured to combine the first and second optical signals and transmit the combined first and second optical signals toward the focusing lens. | 07-26-2012 |
20120189307 | MODULATOR WITH MARKING OF POLARIZATION - A modulator with polarization marking comprising two input ports for receiving two optical signals at one wavelength, and exhibiting essentially perpendicular optical polarization states, capable of phase-modulating those signals with data signals and of combining them with polarization, characterized in that it comprises a source of phase overmodulation for overmodulating the phase of one of said two optical signals, said phase overmodulation exhibiting a modulation frequency substantially lower than the modulation frequency of said data signals. A method and a coherent receiver are also disclosed. | 07-26-2012 |
20120207474 | PLC-TYPE DEMODULATOR AND OPTICAL TRANSMISSION SYSTEM - The invention provides a PLC-type DP-QPSK demodulator that reduces connection loss between a polarization beam splitter and a 90-degree hybrid circuit and aims at reducing the manufacturing cost and an optical transmission system using the same. In an embodiment of the invention, a PLC-type DP-QPSK demodulator that receives a DP-QPSK signal includes one PLC chip having a planar lightwave circuit. Input ports and output ports of signal light are provided at an input end and at an output end of the PLC chip, respectively. Within the planar lightwave circuit, there are integrated a polarization beam splitter that splits the DP-QPSK signal into an X-polarization QPSK signal and a Y-polarization QPSK signal, and two 90-degree hybrid circuits that mix the X-polarization QPSK signal and local oscillation light and the Y-polarization QPSK signal and local oscillation light, respectively, split each QPSK signal into orthogonal components I, Q and output them. | 08-16-2012 |
20120207475 | RECEIVING APPARATUS, SENDING APPARATUS, SYSTEM AND METHOD FOR OPTICAL POLARIZATION DIVISION MULTIPLEXING - The present invention discloses a receiving apparatus, a sending apparatus, a system and a method for optical polarization division multiplexing. The receiving apparatus includes: an optical splitter, configured to: split a received polarization-multiplexed optical signal into two identical polarization-multiplexed optical signals, where the two polarization-multiplexed optical signals both include a first State Of Polarization (SOP) optical signal and a second SOP optical signal, and the first SOP optical signal is an optical signal when a horizontal-SOP optical signal is transmitted to the optical splitter, and the second SOP optical signal is an optical signal when a vertical-SOP optical signal is transmitted to the optical splitter; a horizontal optical signal obtaining apparatus, connected to the optical splitter and configured to separate the horizontal-SOP optical signal; and a vertical optical signal obtaining apparatus, connected to the optical splitter and configured to separate the vertical-SOP optical signal. | 08-16-2012 |
20120207476 | DATA TRANSMISSION SYSTEM AND METHOD - A method of transmitting data using electromagnetic waves, comprising the steps of providing ( | 08-16-2012 |
20120219294 | DIGITAL SIGNAL-TO-SIGNAL BEAT NOISE REDUCTION FOR FILTER-LESS COHERENT RECEIVING SYSTEM - Systems and methods are disclosed for a filter-less coherent receiving system with a filter-less coherent receiver frontend; a signal-signal beat-noise detector coupled to the filter-less coherent receiver frontend; and a real-time processor coupled to the filter-less coherent receiver frontend and the signal-signal beat-noise detector to reject signal-signal interference. | 08-30-2012 |
20120224852 | System, Method, and Apparatus for High-Sensitivity Optical Detection - An apparatus transmits data using a format where information bits intended for transmission are mapped into symbols each carrying a plurality of bits, some of which are encoded through pulse position modulation (PPM) format and the rest of which are encoded through an additional modulation format on each PPM pulse. The additional modulation format for the PPM pulse may be at least one of a polarization-division-multiplexed (PDM) modulation, phase-shift keying (PSK) modulation, polarization shift keying (PolSK) modulation, amplitude modulation (AM), quadrature-amplitude modulation (QAM) modulation, or a combination thereof. In one embodiment, the additional modulation of the PPM pulses is through polarization-division-multiplexed quadrature-phase-shift keying (PDM-QPSK). The unique combined use of PDM-QPSK and PPM produces much higher receiver sensitivity than either PPM or PDM-QPSK alone. | 09-06-2012 |
20120237221 | COHERENT OPTICAL SIGNAL PROCESSING - Coherent optical signal processing is performed in a coherent receiver (or diagnostic/testing apparatus) that converts an amplitude and/or angle-modulated optical signal into two electrical signals. A simple receiver can only detect one phase of the signal and only the polarization that is aligned with a local oscillator laser polarization. To detect both phases and both polarizations, two sets of two interferometers, one each with a π/2 phase shift are required. Coherent optical signal processing methods, apparatus, techniques, etc. are disclosed that include individual components comprising a polarization combiner, a Savart device and photodetection apparatus with substantially reduced temperature and alignment sensitivity operating in optical communication systems and/or subsystems. The various embodiments can be used alone or in such combinations to provide improved coherent optical signal processing in a receiver. | 09-20-2012 |
20120251110 | COMPUTATIONALLY-EFFICIENT EQUALIZATION IN POLMUX OFDM TRANSMISSION WITH DIRECT-DETECTION VIA JOINT TRANSMITTER AND RECEIVER PROCESSING - A method for joint transmitter and receiver processing for computationally efficient equalization in polarization multiplexed (POLMUX) optical orthogonal frequency division multiplexed (OFDM) transmission with direct detection. | 10-04-2012 |
20120251111 | OPTOELECTRONIC WAVELENGTH CONVERTER FOR POLARIZATION MULTIPLEXED OPTICAL SIGNALS - A wavelength converter that operates on an optical signal having single or multiplexed polarizations and which exhibits any modulation format. | 10-04-2012 |
20120251112 | METHOD AND SYSTEM FOR COHERENT EQUALIZATION OF CHROMATIC DISPERSION OF OPTICAL SIGNALS IN A FIBER - Method and system for optimally equalizing distortion of an optical data channel carrying coherent optical signals with a given analog bandwidth B. A receiving end with IQ paths receives signals and a balanced detector detects signals in each path. The bandwidth of the detected signals is reduced by a factor of N by filtering the output of each path using an AAF with a cutoff frequency optimized to the analog bandwidth 2B/N of each path, where the AAF has deterministic attributes and introducing Known ISI. The signal is sampled at the AAF output by an ADC, at a sampling rate of 2B/N. The samples of each path are post-processed by a digital processor operating at a data rate of 2B/N, where post-processing represents the compensation of the distortion and the input data stream is reconstructed by optimally decoding the output of the processor using a decoder, which compensates the ISI. | 10-04-2012 |
20120257895 | FOUR-DIMENSIONAL OPTICAL MULTIBAND-OFDM FOR BEYOND 1.4TB/S SERIAL OPTICAL TRANSMISSION - Systems and methods are disclosed to perform four-dimensional optical multiband OFDM communication by organizing an N-dimensional (ND) signal constellation points as a signal matrix; performing 2D-inverse FFT and 2D-FFT to perform modulation and demodulation, respectively; and applying both orthogonal polarizations in the OFDM communication to deal with chromatic dispersion, PMD and PDL effects, and multidimensional signal constellation to improve optical signal-to-noise ratio (OSNR) sensitivity. | 10-11-2012 |
20120257896 | CODED MULTIDIMENSIONAL PULSE AMPLITUDE MODULATION FOR ULTRA-HIGH-SPEED OPTICAL TRANSPORT - Systems and methods are disclosed to provide optical communication by using subcarriers as individual bases functions, obtaining signal constellation points of an N-dimensional pulse amplitude modulation (ND-PAM) constellation diagram as an N-dimensional Cartesian product of a one-dimensional PAM; and transmitting the N-dimensional signal constellation point over all N orthogonal subcarriers serving as individual bases functions. | 10-11-2012 |
20120263464 | Adaptive Cross-Polarization Modulation Cancellers for Coherent Optical Communication Systems - For coherent fiber optic communications, the nonlinear XPolM impairment is the most important issue to realize over-100 Gbps high-speed transmissions. A method provides a way to cancel time-varying XPolM crosstalk by introducing multi-stage adaptive mechanism. In the method, a low-complexity adaptive filtering based on recursive least-squares (RLS) first tracks the time-varying crosstalk along with the per-survivor trellis-state decoding. The estimated channel and the decoded data are then used to calculate the empirical covariance, which is in turn exploited to obtain more accurate channel estimates by means of optimal-weighted least-squares. This is performed with a low-complexity processing over frequency domain with fast Fourier transform. The performance is significantly improved with turbo principle decoding, more specifically, iterative decoding and iterative estimation over a block. | 10-18-2012 |
20120263465 | OPTICAL TRANSMISSION SYSTEM AND OPTICAL TRANSMISSION METHOD - An optical transmission system includes: a two-lightwave generator for generating optical signals having wavelengths λ | 10-18-2012 |
20120263466 | MULTIDIMENSIONAL HYBRID MODULATIONS FOR ULTRA-HIGH-SPEED OPTICAL TRANSPORT - Systems and methods are disclosed with a spatial-domain-based multi-dimensional coded-modulation scheme that improves dramatically OSNR sensitivity and tolerance to fiber nonlinearities by using D-dimensional signal constellations, where D=2(2+M)N. The factor 2 originates from two polarizations, 2+M electrical basis functions are selected (2 in-phase/quadrature channels and M pulse-position like basis functions), and N represents the number of orbital angular momentum (OAM) states used in FMFs/MMFs. For single mode fiber applications N is 1. | 10-18-2012 |
20120263467 | Polmux-OFDM-DD Transmitter and Receiver for Reduced Complexity and Overhead in Optical Access/Metro Transmission - An optical communication system includes a polarization multiplexed orthogonal frequency-division multiplexing POLMUX-OFDM transmitter for generating a POLMUX-OFDM double sideband signal, an optical processing path for processing the double sideband signal from the transmitter; an analog-to-digital convert ADC-OFDM receiver coupled to the optical processing path for receiving the double sideband signal processed by the optical path; and a block-diagonal multiple-input multiple-output MIMO equalizer responsive to the receiver for enabling correct operation for a completely random incoming signal polarization state without adaptive polarization control at said receiver, which enables complexity. | 10-18-2012 |
20120263468 | Generation of Optical Quadrature Duobinary Format Using Optical Delay - An optical method for generating an optical quadrature duobinary QDB signal includes receiving a quadrature phase-shift-keying QPSK signal, and adding a delay to the received quadrature phase-shift-keying QPSK signal to generate an optical quadrature duobinary signal. | 10-18-2012 |
20120269512 | TRANSPORT OF MULTIPLE ASYNCHRONOUS DATA STREAMS USING HIGHER ORDER MODULATION - Aspects of the invention provide transmitters and receivers for managing multiple optical signals. High order modulation, such as phase and/or amplitude modulation, is used to achieve multiple bits per symbol by transporting multiple asynchronous data streams in an optical transport system. One or more supplemental multiplexing techniques such as time division multiplexing, polarization multiplexing and sub-carrier multiplexing may be used in conjunction with the high order modulation processing. This may be done in various combinations to realize a highly spectrally efficient multi-data stream transport mechanism. The system receives a number of asynchronous signals which are unframed and synchronized, and then reframed and tagged prior to the high order modulation. Differential encoding may also be performed. Upon reception of the multiplexed optical signal, the receiver circuitry may employ either direct detection without a local oscillator or coherent detection with a local oscillator. | 10-25-2012 |
20120269513 | OPTICAL RECEPTION DEVICE AND OPTICAL RECEPTION CONTROL METHOD - An optical reception device ( | 10-25-2012 |
20120275791 | METHOD AND APPARATUS FOR IMPLEMENTING PDM-BPSK MODULATION AND QPSK MODULATION IN COMPATIBLE MANNER - A method for implementing Polarization Division Multiplexing Binary Phase Shift Keying (PDM-BPSK) modulation and Quadrature Phase Shift Keying (QPSK) modulation in a compatible manner includes: dividing a direct current (DC) light into a first channel of light and a second channel of light with the same power; separately performing optoelectrical modulation on the first channel of light and the second channel of light and correspondingly outputting a first optical signal and a second optical signal in a Binary Phase Shift Keying (BPSK) format; performing polarization state control on the first optical signal; performing a phase shift on the first optical signal or the second optical signal; and performing optical signal combination with the polarization state preserved on the first optical signal and the second optical signal after the polarization state control and the phase shift, and outputting a PDM-BPSK modulation optical signal or a QPSK modulation optical signal. | 11-01-2012 |
20120301146 | Equivalent-Link Backward Propagation Method for Nonlinearity Compensation in Fiber Transmission Systems - A method includes transmitting an optical signal over an optic link in a communication system, the optical link including an optical fiber and optical amplifier; coupling a coherent receiver in the communication system to the optic link for receiving the optical signal; and processing an output from the coherent receiver with digital signal processing DSP in the communication system, the DSP compensating for impairments of the optical signal due to the fiber optic link with an equivalent-link back-propagation. | 11-29-2012 |
20120308233 | RECEIVER AND CROSS PHASE MODULATION REDUCTION METHOD - A receiver includes: an extraction circuit to extract a phase fluctuation component common to phase data of two polarization components that are separated in a coherent reception of a polarization multiplexing phase modulation optical signal; and a correction circuit to correct the phase data of the two polarization components in accordance with the phase fluctuation component. | 12-06-2012 |
20120308234 | CLOCK RECOVERY METHOD AND CLOCK RECOVERY ARRANGEMENT FOR COHERENT POLARIZATION MULTIPLEX RECEIVERS - Component signal values are derived from component signals and fed to at least one fixed equalizer which generates equalizer output signals. The signals are fed to phase error detectors generating phase error signals. The phase error signals are combined with further phase error signals derived by further error detectors receiving signal values from further equalizers and/or the component signal values directly from sample units. | 12-06-2012 |
20120315043 | TRANSMISSION METHOD, RECEPTION METHOD, TRANSMITTER APPARATUS, AND RECEIVER DEVICE - A polarization state of a transmission signal can be changed at a high speed based on a symbol-rate By switching a first switch, a second switch, and a third switch with time, one of an X-polarized wave_I-signal as a Y-polarized wave_I-signal, a signal caused by performing logical inversion for an X-polarized wave_I-signal, an X-polarized wave_Q-signal and a signal caused by logical inversion for an X-polarized wave_Q-signal is input to a second modulator. Further, by switching the first switch, the second switch and the third switch with time, the second modulator is input one of the X-polarized wave_I-signal as the Y-polarized wave_Q-signal, the X-polarized wave_I-signal, the signal caused by performing logical inversion for the X-polarized wave_I-signal, the X-polarized wave_Q-signal and the signal caused by performing logical inversion for the X-polarized wave_Q-signal. Thereby, a polarization state of a transmission signal can be changed at high speed based on a symbol-rate speed. | 12-13-2012 |
20120321311 | Coherent Interleaved Polarization-Multiplexing Optical Communications with Single IQ Modulator - An inventive method for coherent interleaved polarization-multiplexing PolMux optical communications with a single IQ modulator includes modulating a light source to generate a 50% return-to-zero RZ signal pulse at a frequency Rs, driving a single IQ modulator with inphase I and quadrature phase Q data at a bit rate of sais Rs to introduce phase modulation on said 50% RZ signal pulse to produce a QPSK pulse signal with all symbols being in a same polarization state without any time overlapping; and polarization modulating said QPSK signal to alternatively convert said QPSK signal into two orthogonal polarizations states enabling an interleaving PolMux signal with a symbol rate of Rs/2. | 12-20-2012 |
20130028603 | METHOD AND APPARATUS FOR PERFORMING TEMPORAL POLARIZATION INTERLEAVING IN AN OPTICAL TRANSMITTING SYSTEM - An optical signal transmitting system, comprising: an optical transmitter including one or more input terminals and an output terminal; and a temporal polarization interleaver including an input terminal and an output terminal, wherein the output terminal of the optical transmitter is communicatively coupled to the input terminal of the temporal polarization interleaver, wherein: the optical transmitter is configured to receive one or more input signals through its one or more input terminals, generate an output signal using the one or more input signals, the output signal including a x-polarized tributary and a y-polarized tributary that is pulse-to-pulse aligned with the x-polarized tributary, and transmit the output signal to the temporal polarization interleaver; and the temporal polarization interleaver is configured to receive the output signal from the optical transmitter and cause a predefined phase delay to one of the x-polarized tributary and the y-polarized tributary. | 01-31-2013 |
20130028604 | OPTICAL ADD/DROP MULTIPLEXER - An optical add/drop multiplexer including one or more optical drop multiplexers connected in free space or fused by optical fiber pigtails, a wavelength blocker with an input port connected to an output port of the optical drop multiplexer through the fusion of the fiber pigtails, one or more optical add multiplexers connected in free space or fused by fiber pigtails, a digital signal processor, an analog-to-digital signal converter, a digital-to-analog converter, and a plurality of electronic control and feedback loops for tuning and scanning an optical wavelength. | 01-31-2013 |
20130034354 | POLARIZATION-MULTIPLEXED SIGNAL RECEIVER, POLARIZATION MULTIPLEXING SYSTEM AND POLARIZATION-MULTIPLEXED SIGNAL RECEIVING METHOD - A polarization-multiplexed signal receiver includes a polarization adjustment unit to adjust a polarization state of inputted polarization-multiplexed signal, which is carrying signal data on each of two polarized waves being inputted, based on a control signal and to output the adjusted polarization-multiplexed signal, an optical signal reception unit to convert the polarization-multiplexed signal having the adjusted polarization state into an analog electric signal and output the analog electric signal, | 02-07-2013 |
20130051800 | SYSTEM FOR INTEGRATION OF CHANNELS WITH QUANTUM INFORMATION IN COMMUNICATION NETWORKS - System for integration of channels with quantum information in communication networks. The network includes fibre-optic segments and conventional equipment, whilst a quantum key distribution (QKD) system has devices for the exchange of information by a quantum channel. The system includes at least one filter for each one of the exchange devices and at least one unit for managing conventional and quantum channels that reduces the noise in quantum channels and has at least the following functions: attenuation of insertion power of conventional channels in the network; different polarizations in the various conventional and quantum channels; and changes of wavelength assignment in not only conventional but also quantum channels. | 02-28-2013 |
20130071119 | COMMUNICATION THROUGH PRE-DISPERSION-COMPENSATED PHASE-CONJUGATED OPTICAL VARIANTS - An apparatus comprises an optical transmitter that comprises a processor and at least one optical modulator. The processor is configured to generate electronic representations of at least two pre-dispersion-compensated phase-conjugated optical variants carrying a same modulated payload data for transmission. The at least one optical modulator is configured to modulate the electronic representations, wherein an amount of dispersion induced on the pre-dispersion-compensated phase-conjugated optical variants depends on an accumulated dispersion (AD) of a transmission link through which the pre-dispersion-compensated phase-conjugated optical variants are to be transmitted. The amount of dispersion induced on the phase-conjugated optical variants may be approximately −AD/2, where AD is the accumulated dispersion of the transmission link. The pre-dispersion-compensated phase-conjugated optical variants are different from one another in one or more dimensions such as the polarization of light, the time of transmission, the spatial localization, the optical carrier wavelength, or the subcarrier frequency during transmission. | 03-21-2013 |
20130077973 | SPECTRALLY EFFICIENT MODULATION FOR AN OPTICAL-TRANSPORT SYSTEM - An optical transport system having an optical add-drop multiplexer configured to reduce inter-channel crosstalk by driving Mach-Zehnder pulse carvers in its optical transmitters with electrical drive signals whose swing range is smaller than voltage 2V | 03-28-2013 |
20130084069 | DIGITAL LIGHT PATH LABELING SYSTEM WITH DUAL POLARIZATION QUATERNARY PHASE-SHIFT KEYING MODULATION - A method and system for encoding and determining labels in a Dual Polarization (DP) Quaternary Phase Shift Keying (QPSK) signal is provided. A label frame, signature sequence, and data payload are combined using a complementary constant-weight code encoding (CCWC) encoder, the output of which is deinterleaved and differentially precoded to generate a polarized tributary of a DP-QPSK signal. This encoding can be duplicated for a second tributary of the DP-QPSK signal. The label can be determined using one or more polarizers and corresponding low-speed photodetectors, each applied to a copy of the DP-QPSK signal. The strongest output of the photodetectors is then used to determine the label. Alternatively, the DP-QPSK signal can be viewed as having XI, XQ, PH, and PV tributaries. These tributaries can then be translated into XI, XQ, YI, and YQ tributaries are encoded into a standard DP-QPSK signal. | 04-04-2013 |
20130108270 | VARIABLE BIT-RATE QPSK TRANSMITTER AND METHOD EMPLOYING POLARIZATION MANIPULATION | 05-02-2013 |
20130121698 | Systems And Methods For Processing Space-Multiplexed Optical Signals - In one embodiment, an optical system for processing space-multiplexed optical signals includes an input fiber that propagates multiple spatially-separated optical signals, a photonic signal processor that receives the multiple spatially-separated optical signals and simultaneously processes those signals, and an output fiber that receives at least one of the processed signals. | 05-16-2013 |
20130136449 | COMMUNICATION THROUGH MULTIPLEXED ONE-DIMENSIONAL OPTICAL SIGNALS - An example apparatus comprises an optical transmitter which includes a first processor and at least two optical modulators. The first processor is configured to generate a first electronic representation for each of at least two optical signals for carrying payload data modulated according to a one-dimensional (1-D) modulation format, and to induce on respective ones of the first electronic representations an amount of dispersion that depends on a power-weighted accumulated dispersion (AD | 05-30-2013 |
20130136450 | SIGNAL EQUALIZER IN A COHERENT OPTICAL RECEIVER - A signal equaliser for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments. | 05-30-2013 |
20130136451 | OPTICAL TRANSFER SYSTEM, OPTICAL TRANSMISSION DEVICE, AND OPTICAL RECEPTION DEVICE - In an optical transfer system, an optical transmission unit generates an optical signal in which respective polarization components are alternately present on a time axis, a time period during which the respective polarization components are simultaneously present on the time axis is substantially zero, and a symbol repetition cycle of optical signals of the respective polarization components becomes Ts, an optical reception unit causes an interference between local oscillation light and a received optical signal and converts an interfered optical signal to an electric signal, and a received electric-signal processing unit performs analog-digital conversion of an electric signal, elimination of a delay difference of Ts/2 between the respective polarized signal components, and adaptive equalization of a distortion other than the delay difference. | 05-30-2013 |
20130148965 | MULTIPROTOCOL TRANSPORT USING POLARIZATION DIVISION MULTIPLEXING - Using polarization modulation techniques to simultaneously transmit two different data streams (formatted according to two different protocols) over a single optical wavelength. A first data stream that is encapsulated for transport using a first transport protocol, and a second data stream that is encapsulated for transport using a second transport protocol are received. The first data stream is modulated on a wavelength with a first polarization mode of a polarization division modulation scheme to produce a first modulated data stream and the second data stream is modulated on the wavelength with a second polarization mode of the polarization division multiplex transmission scheme to produce a second modulated data stream having the second polarization mode. The second polarization mode is orthogonal to the first polarization mode. The first and second data streams are combined onto a single wavelength for transmission over a single optical fiber using a polarization beam combiner. | 06-13-2013 |
20130148966 | OPTICAL MODULE HAVING A PLURALITY OF OPTICAL SOURCES - An optical module that outputs a wavelength multiplexed optical signal is disclosed. The optical module provides at least first to third optical source, a wavelength multiplexer, a polarization rotator, and a polarization multiplexer. The optical sources each outputting first to third optical signals with a wavelength different from others. The wavelength multiplexer multiplexes the first optical signal with the third optical signal. The polarization rotator rotates the polarization vector of one of the multiplexed first and third optical signals and the second signal by substantially 90°. The polarization multiplexer multiplexes the polarization rotated optical signal with the second optical signal. | 06-13-2013 |
20130148967 | DISTORTION COMPENSATOR, OPTICAL RECEIVER, DISTORTION COMPENSATOR AND OPTICAL RECEIVER CONTROLLING METHODS, AND OPTICAL TRANSMISSION SYSTEM - A distortion compensator, an optical receiver and a transmission system including an operation selectively compensating for linear waveform distortion exerted on an optical signal via a plurality of distortion compensators and compensating for nonlinear waveform distortion exerted on the optical signal using nonlinear distortion compensators. | 06-13-2013 |
20130163988 | BLIND EQUALIZATION FOR POLARIZATION-SWITCHED QPSK OPTICAL COMMUNICATIONS - An apparatus, e.g. an optical receiver, includes an optical front end and an equalizer. The front end is configured for receiving an optical signal bearing first and second symbols on respective first and second polarization channels. The equalizer is configured to 1) select a first cost function if the first symbol has greater energy than the second symbol, 2) select a second different cost function if the second symbol has a greater energy than the first symbol, and 3) based on the selected cost function, update coefficients of an adaptive filter configured to demultiplex and equalize the first and second polarization channels. | 06-27-2013 |
20130183036 | OPTICAL POLARIZATION MULTIPLEXING USING LASER ARRAYS - An optical data system and method are disclosed. An optical data system includes an array of lasers that are modulated by the plurality of modulation signals to provide a plurality of pairs of orthogonally polarized optical data signals. The optical data system further includes an optical multiplexing system to combine each of the pairs of orthogonally polarized optical data signals to provide a plurality of dual-channel optical data signals. | 07-18-2013 |
20130188952 | COMMUNICATIONS DEVICE WITH DISCRIMINATOR AND WAVELENGTH DIVISION MULTIPLEXING FOR GENERATING INTERMEDIATE FREQUENCY SIGNAL AND RELATED METHODS - A communications device includes a transmitter device including first and second optical sources, a first optical coupler coupled to the first and second optical sources, and a first modulator coupled to the first optical coupler and to modulate a combined carrier signal including the first and second optical carrier signals with an RF input signal. The communications device includes a receiver device having a second modulator to further modulate the modulated combined carrier signal with an LO signal, a FM-PM discriminator coupled to the second modulator and to convert the modulated combined carrier signal to an intensity modulated combined carrier signal based upon the LO signal, a second optical coupler coupled to the FM-PM discriminator and to generate first and second intensity modulated carrier signals, and an optical-to-electrical converter coupled to the second optical coupler and to generate an IF signal. | 07-25-2013 |
20130195455 | METHOD AND DEVICE FOR TRANSMISSION AND RECEPTION OF A POLARIZATION MULTIPLEXED OPTICAL SIGNAL - A method and a device transmit and receive a polarization multiplexed signal in an optical network. The device has a first carrier of a first polarization and a second carrier of a second polarization at different frequencies. Furthermore, a communication system contains such a device which reduces overall network costs. | 08-01-2013 |
20130195456 | OPTICAL MULTIPLEXING USING LASER ARRAYS - An optical data system and method are disclosed. The system can be an integrated optical data transmission system that includes an array of lasers that are modulated by a plurality of modulation signals to provide a plurality of sets of optical data signals. Each of the optical data signals in each of the plurality of sets can have a distinct wavelength. The system can also include a wavelength division multiplexing system to combine each of the plurality of sets of optical data signals to generate a plurality of multi-channel optical data signals that are transmitted via a respective plurality of optical transmission media. | 08-01-2013 |
20130216228 | OPTICAL NETWORK UNIT, OPTICAL ACCESS NETWORK AND A METHOD FOR EXCHANGING INFORMATION - An Optical Access Network, a Optical Network Unit (ONU) and various methods for exchanging information are provided. The method may include: receiving, by the ONU, a pilot signal and downstream information signals; wherein the pilot signal is received at a pilot frequency slot and the downstream information signals are received at a downstream information frequency slot; wherein the ONU is allocated with a spectral slice that comprises the pilot frequency slot, the downstream information frequency slot, a guard frequency slot and an upstream information frequency slot; wherein at least one other spectral slice is allocated for exchanging information with at least one other group of ONUs; splitting the downstream information signals to downstream information signals portions; splitting the pilot signals to pilot signals portions; detecting downstream information, in response to at least a first portion of downstream information signals; modulating a portion of the pilot signal by upstream information signals to provide upstream information signals that are within the upstream information frequency slot; modulating a second portion of the downstream information signals by the upstream information signals to provide upstream secondary signals that are outside the pilot frequency slot, the downstream information frequency slot and the upstream information frequency slot; and upstream transmitting the upstream information signals and the upstream secondary signals. | 08-22-2013 |
20130243433 | INVERSE CHANNEL APPARATUS AND TRANSMITTER, RECEIVER AND SYSTEM CONTAINING THE APPARATUS - The embodiments of the present invention provide an inverse channel apparatus and transmitter, receiver and system containing the apparatus; wherein the inverse channel apparatus comprises: an inverse nonlinear calculating unit configured to perform nonlinear additive calculation and nonlinear multiplicative calculation on input signals, so as to obtain signals containing nonlinear damage of the input signals on at least one polarization state; and an inverse linear calculating unit configured to calculate signals containing nonlinear damage and linear damage of the input signals on at least one polarization state according to the signals containing nonlinear damage of the input signals on at least one polarization state and a linear function of a channel. The advantages of the embodiments of the present invention exist in that a transmitted signal is recovered by being passed through an inverse channel after or before being transmitted in a practical channel, thereby effectively compensating for intra-channel nonlinear damage of an optical fiber communication system. | 09-19-2013 |
20130243434 | OPTICAL COMMUNICATION SYSTEM, OPTICAL COMMUNICATION METHOD, OPTICAL COMMUNICATION DEVICE, AND METHOD AND PROGRAM FOR CONTROLLING THE SAME - In order to perform the polarization demultiplexing of the polarization multiplexed BPSK signal using a small-scale circuit by means of optical phase modulation of the polarization multiplexed BPSK signal into the pseudo polarization multiplexed QPSK signal, an optical communication system for communicating by using polarization multiplexed optical signals includes an optical phase modulation means for modulating phases of a plurality of optical signals employing BPSK modulation system including information to be communicated, and for generating a plurality of optical signals to become signals by pseudo QPSK modulation system; and a signal restoration means for performing polarization demultiplexing of a plurality of polarization multiplexed optical signals from a plurality of optical signals modulated into the pseudo QPSK modulation system, and for restoring the information to be communicated. | 09-19-2013 |
20130251369 | SIGNAL PROCESSING CIRCUIT, SIGNAL PROCESSING METHOD, OPTICAL RECEIVER AND OPTICAL COMMUNICATION SYSTEM - In order to reduce influence of noise due to a phase deviation, and to estimate an amount of phase compensation with superior accuracy in a polarization multiplexing/demultiplexing optical communication system, a signal processing circuit includes: optical frequency deviation estimating unit for estimating a frequency deviation which is a difference between a frequency of local light and a frequency of the optical carrier wave which is included in a signal data which corresponds to the polarizations and are generated by mixing a plurality of the optical carrier waves with the local light, which optical carrier wave is phase-modulated and have polarizations able to be demultiplexed and for outputting the estimated frequency deviation as an estimated value; for outputting the estimated frequency deviation as an estimated value; optical frequency deviation compensation amount analyzing unit for calculating an amount of frequency compensation which is an amount of compensation to make a phase of the signal data rotated so as to reduce the frequency deviation, on the basis of a plurality of the estimated values estimated per the signal data; optical frequency deviation compensating unit for making the phase of the signal data rotated correspondingly to the amount of the frequency compensation; optical phase deviation estimating unit for estimating a phase deviation included in each of input signal data and is a difference between a phase of the optical carrier wave and a phase of the local light; and optical phase deviation compensating unit for making the phase of the signal data rotated correspondingly to the phase deviation. | 09-26-2013 |
20130251370 | OPTICAL RECEIVER, POLARIZATION SEPARATION DEVICE AND POLARIZATION SEPARATING METHOD - Provided is a polarization separation device which converges filter coefficients used in polarization separating process more quickly. | 09-26-2013 |
20130259479 | OPTICAL TRANSCEIVING APPARATUS, OPTICAL TRANSMITTING METHOD, AND OPTICAL TRANSMITTING DEVICE - An optical transceiving apparatus includes an optical transmitting device performing polarization multiplexing on and transmitting as polarization multiplexed signal light, a first signal light of a predetermined polarization direction and a second signal light of a polarization direction different from the predetermined polarization direction; an optical receiving device receiving the signal light transmitted from the optical transmitting device through an optical transmission path; an acquiring unit acquiring information indicative of magnitude relation of intensity between the first signal light and the second signal light included in the signal light received by the optical receiving device; and a control unit controlling the magnitude relation of intensity between the first signal light and the second signal light included in the signal light output from the optical transmitting device, to be opposite to the magnitude relation indicated by the information acquired by the acquiring unit. | 10-03-2013 |
20130259480 | OPTICAL TRANSMISSION APPARATUS - An optical transmission apparatus includes transmitters configured to correspond to the polarization multiplexing optical signals, each of at least two of the transmitters including a first computing unit that computes, based on information regarding an optical transmission line including a plurality of spans and a polarization multiplexing optical signal, data waveform information regarding the transmitter and transmits the data waveform information to at least one another transmitter provided for at least one another polarization multiplexing optical signal, and a second computing unit that receives data waveform information from the at least one another transmitter provided for the at least one another polarization multiplexing optical signal and pre-equalizes or reduces cross phase modulation occurring in the optical transmission line of a transmission signal based on the data waveform information received from the at least one another transmitter provided for the at least one another polarization multiplexing optical signal. | 10-03-2013 |
20130272704 | Linear Dispersion Polarization-Time Codes and Equalization in Polarization Multiplexed Coherent Optical System - A method of optical communication comprising encoding four modulated symbols to generate four encoded symbols in two orthogonal polarizations and transmitting the four encoded symbols in two successive time slots. An optical communication apparatus comprising a processor configured to receive two sequences of digital symbols in a plurality of time slots, wherein the two sequences correspond to two components of two orthogonal polarizations, wherein one digital symbol per polarization is received in each of the plurality of time slots, divide each of the two sequences into a plurality of groups using a modulo operation of time, wherein each group comprises two digital symbols received in two consecutive time slots, and adaptively equalize the four digital symbols of the two consecutive time slots using a 4×4 matrix to generate four modulated symbols, wherein the 4×4 matrix comprises 16 tap-vectors. | 10-17-2013 |
20130272705 | METHOD AND SYSTEM FOR WDM TRANSMISSION WITH CHROMATO-TEMPORAL ENCODING - A transmitter and a receiver for an optical telecommunication system of the WDM type are disclosed. In one aspect, the transmitter uses a chromato-temporal encoder which, with each block of symbols to be transmitted, associates a code matrix, where each element of the matrix corresponds to a wavelength and a use of the channel. The transmitter includes multiple modulators, where each modulator modulates a laser beam at a wavelength during a use of the channel by an element corresponding to the code matrix. The beams modulated in this manner are multiplexed in an optical fiber. Another embodiment using both a wavelength and a polarization encoding is also proposed. | 10-17-2013 |
20130279910 | Banded Semiconductor Optical Amplifier - A semiconductor optical amplifier module may include a beam splitter to split an optical signal into two polarization optical signals including a first polarization optical signal with a Transverse Magnetic (TM) polarization provided along a first path of two paths, and a second polarization optical signal with a Transverse Electric (TE) polarization provided along a second path of the two paths; a first rotator to rotate the TM polarization of the first polarization optical signal to TE polarization; a first semiconductor optical amplifier to amplify the rotated first polarization optical signal to output a first resultant optical signal; a second semiconductor optical amplifier to amplify the second polarization optical signal; and a second rotator to rotate the polarization of the amplified second polarization optical signal to output a second resultant optical signal; and a beam combiner to combine the first resultant optical signal and the second resultant optical signal. | 10-24-2013 |
20130279911 | RAMAN PUMP CIRCUIT - A Raman pump may include a dual output laser configured to output two optical signals; a delay interferometer configured to delay a first of the two optical signals to decorrelate the two optical signals from each other; and a combiner configured to combine the delayed first of the two optical signals and a second of the two optical signals to provide a Raman amplification signal. | 10-24-2013 |
20130279912 | BANDWIDTH EFFICIENT DUAL CARRIER - In some examples, a transmit assembly is described that may include a first optical transmitter, a second optical transmitter, and a polarizing beam combiner. The first optical transmitter may be configured to emit a first optical data signal centered at a first frequency. The second optical transmitter may be configured to emit a second optical data signal centered at a second frequency offset from the first frequency by a nominal offset n. The polarizing beam combiner may be configured to generate a dual carrier optical data signal by polarization interleaving the first optical data signal with the second optical data signal. An output of the polarizing beam combiner may be configured to be communicatively coupled via an optical transmission medium to a polarization-insensitive receive assembly. | 10-24-2013 |
20130279913 | METHOD FOR CONTROLLING POLARIZATION MULTIPLEXED OPTICAL SIGNAL - An optical signal transmitter includes: first outer modulator to generate first modulated optical signal, the first outer modulator including a pair of optical paths and a first phase shifter to give phase difference to the pair of optical paths; second outer modulator to generate second modulated optical signal, the second outer modulator including a pair of optical paths and a second phase shifter to give phase difference to the pair of optical paths; combiner to generate polarization multiplexed optical signal by combining the first and second modulated optical signals; phase controller to control the phase difference by the first phase shifter to A−Δφ and control the phase difference by the second phase shifter to A+Δφ; and power controller to control at least one of the first and second outer modulators based on AC component of the polarization multiplexed optical signal. | 10-24-2013 |
20130287398 | MULTI-CHANNEL OPTICAL TRANSCEIVER WITH OFFSET QUADRATURE AMPLITUDE MODULATION - The present disclosure provides a multi-carrier optical transmitter, receiver, transceiver, and associated methods utilizing offset quadrature amplitude modulation thereby achieving significant increases in spectral efficiency, with negligible sensitivity penalties. In an exemplary embodiment, an optical transmitter includes circuitry configured to generate a plurality of optical subcarriers, a plurality of data signals for each of the plurality of subcarriers, and a plurality of modulator circuits for each of the plurality of subcarriers, wherein each of the plurality of modulator circuits includes circuitry configured to offset an in-phase component from a quadrature component of one of the plurality data signals by one-half baud period. | 10-31-2013 |
20130302034 | ACCESSING LP TRANSPONDERS WITH CP TERMINALS VIA WAVEFRONT MULTIPLEXING TECHNIQUES - The invention is about a method and apparatus for grouping multiple satellite transponders with both (LP) polarization formats in different frequencies through Wave-Front (WF) Multiplexing (muxing) techniques for ground terminals with incompatible (CP) polarization formats. As a result of this invention, linear polarized (LP) transponders can be accessed and efficiently utilized by circularly polarized (CP) ground terminals and vice versa. This invention consists of conventional ground terminals, a unique organization of space assets, and a unique polarization alignment processor. The applications of wavefront multiplexing techniques to satellite communications offer many potential advantages, including improved flexibility and utility efficiency of existing space assets. Our proposed “Polarization Utility Waveforms” is an entirely new concept in VSAT and Earth Station Antenna diversity. The implementation enables antennas to switch between different polarization formats at the press of a button, and provides teleport operators with greater flexibility in how they manage their assets. | 11-14-2013 |
20130308947 | METHOD OF OPTICAL DATA TRANSMISSION USING POLARIZATION DIVISION MULTIPLEXING - Proposed is a method of optical data transmission. A first data signal and a second data signal are received at a same sampling rate. A third data signal and a fourth data signal are generated, using the first and the second data signal, wherein the two data signals are delayed to each other by a delay time that is varied over time. The phase of a first optical signal is modulated in dependence on the third data signal, and the phase of a second optical signal with a same wavelength is modulated in dependence on the fourth data signal. The first optical signal is transmitted in a first polarization plane into an optical fibre, and the second optical signal is transmitted in a second polarization plane orthogonal to the first polarization plane into the optical fibre. | 11-21-2013 |
20130322881 | OPTICAL TRANSMISSION WITH POLARIZATION DIVISION MULTIPLEXING - A optical transmitter and method for transmitting digital data on an optical channel, performing the steps of generating first and second baseband digital signals, modulating a first polarized optical carrier wave component in accordance with the first baseband digital signal, modulating a second polarized optical carrier wave component in accordance with the second baseband digital signal, wherein the second polarized optical carrier wave component has an orthogonal polarization to the first polarized optical carrier wave component and combining the first and second modulated optical carrier wave components into a propagation medium. The first and second baseband digital signals are generated in a correlated manner so that the modulated optical carrier wave components are combined as a modulated single-polarization optical carrier wave. | 12-05-2013 |
20130336654 | OPTICAL RECEIVER, POLARIZATION DEMULTIPLEXER, AND OPTICAL RECEIVING METHOD - In order to appropriately demultiplex the polarization multiplexed BPSK signal without using a training sequence and decreasing the resistance to a frequency offset, an optical receiver includes a coherent optical detection unit receiving an optical signal in which BPSK modulated carrier waves are polarization-multiplexed, performing coherent detection by mixing the received optical signal with local light, and outputting first electrical signals corresponding to the carrier waves; a butterfly FIR filter receiving the first electrical signals and extracting second electrical signals corresponding to each of the carrier waves from the first electrical signals; and a coefficient control unit for calculating a sum of respective phases of the second electrical signals output from the butterfly FIR filter, adaptively controlling tap coefficients of the butterfly FIR filter so that the calculated phase sum may become equal to 0 or π, and outputting tap coefficients after being controlled to the butterfly FIR filter. | 12-19-2013 |
20140003813 | FORWARD ERROR CORRECTION FOR AN OPTICAL TRANSPORT SYSTEM | 01-02-2014 |
20140003814 | PROCESSING THREE-QUADRATURE AMPLITUDE MODULATION (3QAM) TRAFFIC USING A FOUR-BIT PHASE MODULATION SCHEME | 01-02-2014 |
20140003815 | Photonic Integrated Circuit Based Phase Conjugation Devices and Methods | 01-02-2014 |
20140023368 | Method And Apparatus for Stabilization of Optical Transmitter - A DP-QPSK optical transmitter includes an outer MZM comprising a first parent MZM comprising a first child MZM and a second child MZM that modulates a QPSK signal with a first polarization. A second parent MZM includes a first child MZM and a second child MZM that modulates a QPSK signal with a second polarization. The outer Mach-Zehnder modulator multiplexes the first and second polarization embedded into a dual-polarization QPSK signal generation. A first optical detector detects the QPSK signal generated by the first parent MZM with the first polarization. A second optical detector optical detects the QPSK signal generated by the second parent Mach-Zehnder modulator with the second polarization. A bias control circuit generates bias signals on at least one output that stabilize the DP-QPSK signal in response to signals generated by the first and second optical detector using electrical time division multiplexing. | 01-23-2014 |
20140037290 | Method and System for Reducing Noise Associated with Optical Signals - In accordance with an embodiment of the present disclosure a network element comprises a plurality of optically absorbent layers. Each layer of the plurality of optically absorbent layers is configured to receive an optical signal such that the optical signal passes through the layer. The optical signal has a specific polarization state and is associated with noise having a plurality of randomly varying polarization states. Each layer absorbs optical waves having a particular polarization state. The particular polarization state of each layer is different from the polarization state associated with the other layers of the plurality of optically absorbent layers. The plurality of layers are coupled together such that as the optical signal and associated noise pass through the plurality of layers, the network element absorbs the associated noise more than the polarized optical signal to improve an Optical Signal to Noise Ratio (OSNR) of the optical signal. | 02-06-2014 |
20140037291 | BUTTERFLY FILTER COEFFICIENT SETTING METHOD AND DEVICE, RECEIVER AND RECEIVING METHOD - The present invention relates to a butterfly filter coefficient setting method and device, a receiver, and a receiving method. The receiver is a DP-CO-OFDM receiver, comprising: a phase recovery device configured to perform a phase recovery of a received signal one OFDM symbol by one OFDM symbol, so as to obtain a phase-recovered first polarization signal and a phase-recovered second polarization signal; a butterfly filter configured to perform butterfly filtration of the phase-recovered first polarization signal and the phase-recovered second polarization signal one OFDM symbol by one OFDM symbol, so as to obtain a butterfly-filtered first polarization signal and a butterfly-filtered second polarization signal; a coefficient setting unit configured to set a filter coefficient used by the butterfly filter for the current OFDM symbol; and a data recovery device configured to recover data from the butterfly-filtered first polarization signal and the butterfly-filtered second polarization signal. | 02-06-2014 |
20140050476 | SYSTEMS AND METHODS FOR THE COMPENSATION OF NONLINEAR CROSS POLARIZATION AND CROSS PHASE MODULATION IN DUAL POLARIZATION COHERENT CHANNELS - The present disclosure provides systems and methods for the compensation of signal distortion in fiber optic communication systems and the like. More specifically, the present disclosure provides an orthogonal polarization detection and broadband pilot (OPDBP) technique for the compensation of nonlinear cross polarization (i.e. nonlinear cross polarization modulation) (XPolM) induced noise and nonlinear nonlinear cross phase modulation (XPM) induced noise in a high data rate polarization multiplexed (PM) multilevel-quadrature amplitude modulated (M-QAM) channel due to neighboring channels. This approach allows for the compensation of both XPolM and XPM simultaneously, providing several dBs of optical reach extension. The approach uses a pilot tone based orthogonal polarization detection scheme with broadband (i.e. a few GHz wide) filtering of the pilot tones. | 02-20-2014 |
20140050477 | METHOD OF OPTICAL DATA TRANSMISSION USING POLARIZATION DIVISION MULTIPLEXING - Proposed is a method of optical data transmission. The method comprises different steps. A first optical signal and a second optical signal are generated, such that the optical signals possess a same wavelength, respective phases, which are modulated in dependence on respective data values, and respective polarization states, which are essentially orthogonal to each other. A combined optical signal is generated, by combining the optical signals, such that the combined optical signal possesses a polarization state with a predetermined variation. The combined optical signal is transmitter over an optical transmission line and received. Two time-discrete sampled signals are generated, by sampling the received optical signal along two orthogonal polarization planes. Two filtered signals are generated, by filtering the time-discrete sampled signals in the time-discrete domain, using a function that is indicative of the respective predetermined variation. Finally, respective data values are derived from the filtered signals. | 02-20-2014 |
20140064728 | METHOD AND APPARATUS FOR SUPPRESSING OPTICAL BEAT INTERFERENCE NOISE IN RAMAN AMPLIFIERS - A method and apparatus for suppressing pump-mode optical beat interference noise in a Raman amplified fiber link of an optical network, wherein a wavelength of a laser beam generated by a first pump laser and a wavelength of a laser beam generated by a second pump laser of a pair of polarization multiplexed pump lasers are detuned with respect to each other to suppress the optical beat interference, OBI, noise in the Raman amplified fiber link of said optical network. | 03-06-2014 |
20140064729 | POLARIZATION DIVERSE DEMULTIPLEXING - An optical demultiplexing device includes a first portion operative to receive an input optical signal having a first polarization, a second polarization and multiple channels, and split the input optical signal into a first optical signal having the first polarization and a second optical signal having the first polarization, and an optical demultiplexing portion communicatively connected to the polarization splitter portion, the optical demultiplexing portion operative to receive a combination of the first optical signal and the second optical signal, and output each channel of the first optical signal and the second optical signal to a photodetector device corresponding to each channel. | 03-06-2014 |
20140072303 | ULTRA DENSE WDM WITH AGILE AND FLEXIBLE DSP ADD-DROP - A system, e.g. for optical communication, includes an I-Q modulator and a transmission signal processor. The I-Q modulator is configured to modulate a first light source in response to first I and Q modulation signals. The transmission signal processor is configured to receive a data stream including data corresponding to a first data subchannel. The processor maps the data subchannel to an optical transmission subchannel and outputs the first I and Q modulation signals. The I and Q modulation signals modulate the light source to produce an optical transmission signal that includes wavelength components corresponding to the optical transmission subchannel. | 03-13-2014 |
20140079394 | Optical Communication Of Interleaved Symbols Associated With Polarizations - An apparatus comprises a coherent optical transmitter. The coherent optical transmitter comprises a first modulator for generating a first polarization, a second modulator for generating a second polarization, and a symbol interleaver configured to receive a first symbol stream intended to be transmitted on a first polarization and a second symbol stream intended to be transmitted on a second polarization, to direct one portion of symbols of the first symbol stream to the first modulator for modulation onto the first polarization and another portion of the symbols of the first symbol stream to the second modulator for modulation onto the second polarization, and to direct one portion of symbols of the second symbol stream to the first modulator for modulation onto the first polarization and another portion of the symbols of the second symbol stream to the second modulator for modulation onto the second polarization. | 03-20-2014 |
20140099110 | OPTICAL TRANSMISSION SYSTEM, METHOD OF ADJUSTING OPTICAL TRANSMISSION DEVICE, AND NON-TRANSITORY COMPUTER-READABLE MEDIUM - An optical transmission system includes: a plurality of transmitters that output an optical signal having a frequency different from each other; a process unit that adds a reference signal to at least two of the optical signals, the reference signal having a frequency width narrower than that of the two optical signals, an interval of central frequencies of the reference signals being narrower than that of the two optical signals, a multiplexer that multiplexes optical signals output by the plurality of transmitters; an extract unit that extracts a beat signal generated between the reference signals because of a multiplexing of the multiplexer; and an adjust unit that adjusts a frequency interval of the two optical signals in accordance with an extract result of the extract unit. | 04-10-2014 |
20140112664 | OPTICAL TRANSMISSION SYSTEM AND OPTICAL TRANSMISSION METHOD - An optical transmission system | 04-24-2014 |
20140119731 | OPTICAL RECEIVER, OPTICAL RECEPTION METHOD AND OPTICAL RECEPTION SYSTEM - An optical digital coherent receiver includes: a polarization separation circuit configured to perform polarization separation on a received signal and output polarized signals; and a determination circuit configured to trigger a start of digital signal processing in a stage subsequent to the polarization separation circuit when it is determined that a distribution of a peak of an amplitude of one of the polarized signals has a characteristic corresponding to a modulation method used on a transmitting side. | 05-01-2014 |
20140126909 | OPTICAL SIGNAL MULTIPLEXING METHOD AND OPTICAL MULTIPLEXER - Embodiments of the present invention relate to the optical communication field and disclose an optical signal multiplexing method and an optical multiplexer. The method provided in the present invention includes: adjusting polarization states of two of four optical signals to be multiplexed, and preferably, mutually orthogonal to, the polarization states of the remaining two optical signals; combining one optical signal in the adjusted polarization state with one optical signal in the unadjusted polarization state into one optical signal through polarization multiplexing; and combining the two optical signals obtained through polarization multiplexing into one optical signal. When multiplexing is performed according to the solutions of the present invention, all optical signals are multiplexed into one optical signal based on polarization multiplexing, optical paths traveled by different optical signals differ slightly, and the optical power and the optical field energy distribution differ slightly between different optical signals in the finally multiplexed optical signal. | 05-08-2014 |
20140140699 | Method and Device for Transmitting an Optical Digital WDM Signal Over an Optical Transmission Link or a Passive Optical Network - Arrangement for transmitting an optical digital WDM signal over an optical transmission link or a passive optical network, the signal (S | 05-22-2014 |
20140147117 | OPTICAL MULTILEVEL SIGNAL PRE-EQUALIZATION CIRCUIT, OPTICAL MULTILEVEL SIGNAL PRE-EQUALIZATION TRANSMITTER, AND POLARIZATION-MULTIPLEXED PRE-EQUALIZATION TRANSMITTER - In order to reduce the circuit size for a chromatic dispersion pre-equalization operation, an optical multilevel signal pre-equalization circuit is provided with: (1) a plurality of look-up tables in which a string of middle codes utilizing a symmetry of a signal constellation of a multilevel code or a string of middle codes represented by polar coordinates is stored in association with a waveform response component; and (2) one or more operation circuits to which the waveform response component corresponding to a multilevel signal to be transmitted is inputted from the plurality of look-up tables, and which outputs a pre-equalized output waveform corresponding to the multilevel signal by operating the waveform response components outputted from different look-up tables. | 05-29-2014 |
20140161452 | OPTICAL FREQUENCY DIVISION MULTIPLEXER AND POLARIZATION CONTROL METHOD - An all-optical modulator includes a directional coupling unit that multiplexes, on a carrier light beam, a signal light beam of a modulation signal that a carrier signal at a characteristic frequency is modulated with an information signal. The all-optical modulator includes a nonlinear medium that cross-phase-modulates the carrier light beam with the multiplexed signal light beam, and frequency-multiplexes the information signal in the signal light beam on the carrier light beam to generate an optical frequency division multiplexed signal. The all-optical modulator includes a monitoring control unit that controls a polarization control unit that controls a polarization state of the signal light beam in a direction in which an intensity of a modulation component takes a maximum value, based on the intensity of the modulation component involved in a modulation signal at a desired characteristic frequency of the optical frequency division multiplexed signal. | 06-12-2014 |
20140178071 | GENERATION OF POLARIZATION-ALTERNATED QPSK FORMAT - Methods, structures and systems for generating different polarization multiplexed signals wherein the drivers of the modulators are generic while a software-controlled manager allows the carrying of any standard 10 G/40 G/100 G data while—at the same time—being adaptively adjustable according to specific link requirements and users' requests in both dispersion-managed and uncompensated links. | 06-26-2014 |
20140199068 | OPTICAL POLARIZATION DEMULTIPLEXING FOR A COHERENT-DETECTION SCHEME - An optical receiver having a plurality of optical IQ modulators arranged in a butterfly configuration and configured to operate as an optical polarization de-multiplexer. The optical receiver further has (i) an opto-electric circuit configured to apply optical homodyne detection to an optical input signal received by the optical receiver and (ii) a controller configured to generate one or more control signals for driving the IQ modulators of the plurality based on one or more electrical feedback signals received from the opto-electric circuit. | 07-17-2014 |
20140212136 | OPTICAL TRANSMITTER AND MODULATED OPTICAL SIGNAL GENERATING METHOD - An optical transmitter includes: an optical modulator including a first modulation unit and a second modulation unit respectively configured to propagate a first optical signal and a second optical signal that are obtained by splitting input light; a signal generator configured to generate a first drive signal and a second drive signal that are respectively supplied to the first modulation unit and the second modulation unit; a phase controller configured to control a phase difference between the first optical signal and the second optical signal in the optical modulator; and a phase difference detector configured to detect the phase difference between the first optical signal and the second optical signal controlled by the phase controller. The signal generator generates the first drive signal and the second drive signal based on the phase difference detected by the phase difference detector. | 07-31-2014 |
20140212137 | PLANAR LIGHTWAVE CIRCUIT AND OPTICAL RECEIVER - A planar lightwave circuit and an optical receiver which reduce degradation in signal quality is provided. | 07-31-2014 |
20140219658 | POLARIZATION MULTIPLEXED SHORT DISTANCE CONNECTION - A network device may include a polarizing multiplexing transmitter, a polarization maintaining (PM) fiber, and a polarizing demultiplexing receiver. The polarizing multiplexing transmitter may generate an optical signal, split the optical signal into a first and a second split optical signal, and modulate the split optical signals based on electrical signals to form first and second modulated optical signals. The polarizing multiplexing transmitter may polarization multiplex the first and second modulated optical signals to form a polarization multiplexed signal and transmit the polarization multiplexed signal via the PM fiber to the polarizing demultiplexing receiver. The polarizing demultiplexing receiver may polarization demultiplex the polarization multiplexed signal to form the first and second modulated optical signals and directly detect the first and the second split optical signal from the first and second modulated optical signals. The polarizing demultiplexing receiver may convert the first and the second split optical signal to the electrical signals. | 08-07-2014 |
20140233949 | OPTICAL COMMUNICATION BASED ON POLARIZATION DEPENDENT COHERENT OPTICAL NYQUIST FREQUENCY DIVISION MULTIPLEXING - An optical transmitter transmits a dual polarization optical Nyquist frequency domain multiplexed signal. The signal includes a first polarization component and a second polarization component. Each component comprises multiple subchannels, possibly having different subchannel bandwidths and different modulation schemes. An optical receiver receives the signal and recovers transmitted data. | 08-21-2014 |
20140241722 | PDM-(M) Ask Optical Systems And Methods For Metro Network Applications - An apparatus, e.g. an optical communication system, includes an optical transmitter and an optical receiver. The transmitter includes a laser configured to provide an optical signal amplitude-modulated among M different levels, e.g. in two polarizations. The receiver is configured to demodulate the optical signal to produce a received symbol constellation including a plurality of symbol rings in a complex I-Q space. | 08-28-2014 |
20140270769 | OPTICAL NETWORK UNIT, OPTICAL ACCESS NETWORK AND A METHOD FOR EXCHANGING INFORMATION - A method for exchanging information with an Optical Network Unit (ONU), the method comprising: receiving, by the ONU, downstream signals that comprise a pilot signal and downstream information signals; wherein the downstream information signals embed first polarization modulated information and second polarization modulated information; wherein the pilot signal is received at a pilot frequency slot and the downstream information signals are received at a downstream information frequency slot that differs from the pilot frequency slot; splitting the downstream signals to first, second, third and fourth sets of signals; wherein the splitting comprises performing a polarization based splitting to provide first and second intermediate sets of signals; wherein the first and second sets of signals originate from the first intermediate set of signals and the third and fourth sets of signals originate from the second intermediate set of signals; generating a fifth set of signals by providing the second and fourth sets of signals to a polarization changing circuit, wherein a polarization direction of the fifth set of signals differs from a polarization direction of the first and second intermediate sets of signals; generating first, second and third sets of detection signals, in response to the first, third and fifth sets of signals; and reconstructing the first polarization modulated information and the second polarization modulated information in response to the first, second and third sets of detection signals. | 09-18-2014 |
20140286638 | SIGNAL PROCESSING APPARATUS AND SIGNAL PROCESSING METHOD - Signal processing means includes carrier compensation means for compensating for a phase difference and a frequency difference between signal light and local light in relation to two polarization signals, so as to generate two carrier compensated signals, symbol determination means for demodulating the two carrier compensated signals on the basis of a signal arrangement of multi-value modulation, symbol rough-determination means for demodulating the two carrier compensated signals on the basis of a signal arrangement in which the number of multi-values of the multi-value modulation is reduced, selection means for selecting either of an output of the symbol determination means and an output of the symbol rough-determination means, and coefficient setting means for updating filter coefficients of polarized wave separation means by using an output selected by the selection means. | 09-25-2014 |
20140294386 | OPTICAL TRANSMITTING APPARATUS AND OPTICAL RECEIVING APPARATUS - An optical transmitting apparatus includes semiconductor laser elements. Upon receiving laser beams, a multiplexed beam is emitted from a wavelength multiplexing filter. The wavelength multiplexing filter includes a triangular prism and a wavelength multiplexing filter film. A front end face and a rear end face of the prism are not parallel to each other so that a prism angle at which a surface parallel to the front end face intersects a surface parallel to the rear end face, is an acute angle. The prism angle is the angle at which the laser beam impinging from the front end face into the triangular prism is reflected by the wavelength multiplexing filter film toward the front end face and the multiplexed beam is directed to the optical axis side of the optical fiber. | 10-02-2014 |
20140294387 | METHOD AND ARRANGEMENT FOR ADAPTIVE DISPERSION COMPENSATION - A received optical signal is coherently demodulated and converted into electrical complex samples (p(n); (px(n), py(n)), which are dispersion compensated in a compensation filter ( | 10-02-2014 |
20140314410 | SYSTEM FOR TRANSMISSION OVER A MULTI-MODE AND/OR MULTI-CORE OPTICAL FIBER - A transmitter for an optical telecommunication system on a weakly multimode fiber is disclosed. One aspect is a transmitter including an encoder transforming each block of symbols to be transmitted into a code matrix, each element of the matrix being relative to a time of use and to a propagation mode of the weakly multimode fiber. The transmitter can include a plurality of modulators respectively associated with the different propagation modes, each modulator modulating a laser beam during a time of use. Each modulator can modulate a laser beam by use of an element of the corresponding matrix, the elements of the matrix of the code being subjected beforehand to an OFDM modulation upstream of said modulators. Each of the modulated beams can be input into the weakly multimode fiber to propagate therein according to a separate mode. | 10-23-2014 |
20140314411 | OPTICAL NYQUIST SUPERCHANNEL GENERATION USING MICROWAVE LOW-PASS FILTERING AND OPTICAL EQUALIZATION - Disclosed are structures and methods for generating a Nyquist superchannel. | 10-23-2014 |
20140328592 | SIGNAL PROCESSING METHOD, OPTICAL RECEIVER AND OPTICAL NETWORK SYSTEM - A signal processing method, an optical receiver and optical network system is provided. The method includes: receiving a first optical signal sent by an optical network unit, generating a second optical signal and modulating a phase of the second optical signal, obtaining at least one path of electrical signals after the first optical signal and the second optical signal separately undergo polarization splitting, frequency mixing, and optical-electrical conversion, outputting a third electrical signal after performing operation processing on the at least one path of electrical signals, and restoring a data signal according to the third electrical signal and performing sending. The embodiments example benefits are greatly reducing complexity of system implementation and maximally reducing a system upgrade cost and an optical power loss. | 11-06-2014 |
20140348506 | OPTICAL TRANSMISSION APPARATUS AND OPTICAL TRANSMISSION METHOD - An optical transmission apparatus includes: an optical amplifier configured to amplify a wavelength multiplexing light to be transmitted, the wavelength multiplexing light being input thereto; a combining unit configured to combine a plurality of non-signal lights in such a way that angles formed between polarization planes of the plurality of non-signal lights of a wavelength of wavelengths belonging to an amplification band of the optical amplifier become equal, the wavelength being different from a wavelength of a polarization multiplexing signal light; and a wavelength multiplexer configured to generate the wavelength multiplexing light to be input to the optical amplifier by multiplexing the plurality of non-signal lights combined by the combining unit and the polarization multiplexing signal light. | 11-27-2014 |
20140348507 | Method, Apparatus, and System for Processing Optical Network Signal - Embodiments of the present invention provide a method, an apparatus, and a system for processing an optical network signal. The method includes: receiving an optical signal sent by an optical line terminal, where the optical signal includes two polarization components perpendicular to each other, and downlink data is modulated on one of the polarization components; dividing the optical signal into two signals, where each signal is the optical signal; demodulating the downlink data from one optical signal and performing, for the other optical signal, vertical polarization rotation processing and processing of modulating uplink data onto two polarization components of the optical signal; sending the other optical signal on which the vertical polarization rotation processing and the uplink data modulation processing are performed to the optical line terminal. With the embodiments of the present invention, signal processing load of the optical network unit and the optical line terminal can be lowered. | 11-27-2014 |
20140363164 | MITIGATION OF POLARIZATION DEPENDENT LOSS IN OPTICAL MULTI-CARRIER/SUPER-CHANNEL TRANSMISSION - Methods and systems for mitigating effects of polarization dependent loss (PDL) in an optical network transmitting a multi-carrier optical signal comprising a plurality of subcarriers may involve assigning and modifying a state of polarization to each subcarrier prior to transmission. An assigned state of polarization for each subcarrier may be modified for the subcarrier in the digital domain and/or the optical domain. Various specific assignment methods may be used, including individual subcarrier assignment, subcarrier set assignment, arbitrary subcarrier group assignment, random assignment, and/or combinations thereof. The assigned states of polarization may be selected based on a resulting minimum PDL-induced peak-to-peak power variation over a sum of the subcarriers for all orientations of a principal axis of PDL. | 12-11-2014 |
20140369684 | METHOD AND APPARATUS FOR DIGITAL POLARIZATION SCRAMBLING IN COHERENT OPTICAL COMMUNICATION SYSTEMS EMPLOYING BOTH TRANSMIT AND RECEIVE DIGITAL SIGNAL PROCESSING - An improved method and apparatus for reducing performance degradation in optical fiber transmission system due to polarization mode dispersion and nonlinear polarization coupling. Digital polarization scrambling with transmit and receive digital signal processing is used to reduce these effects. By performing digital polarization scrambling on all possible states of polarization with respect to the two principle axes of an optical fiber, the SOP dependent penalty is averaged out. The invention also provides a method and apparatus for performing digital polarization scrambling on the transmit side and blinded polarization tracking or synchronized polarization descrambling at the receive side. Using a configurable scrambling speed, the invention works as a polarization scanner low speed SOP rotation or as a scrambler at fast SOP rotation speeds. Synchronization of the transmit scramble and the receive descrambler is achieved with scrambling and descrambling control modules based on a common pseudo random bit sequence. | 12-18-2014 |
20140369685 | SYMBOL TIMING ESTIMATION FOR COHERENT POLARIZATION MULTIPLEX OPTICAL RECEIVERS - A received POLMUX signal is rotated by fixed rotation parameters (Rot | 12-18-2014 |
20140369686 | SYSTEMS AND METHODS FOR NOISE TOLERANT SIGNAL PROCESSING IN PILOT ASSISTED DATA RECEIVERS - The present disclosure provides systems and methods for noise tolerant signal processing in a pilot assisted data receiver, including: given received pilots with common pilot components and individual pilot components, computing coefficients associated with the individual pilot components of the received pilots; and applying the computed coefficients to the received pilots to obtain conditioned pilots. The individual pilot components result from relatively slow changes of the received pilots relative to the common pilot components. The common pilot components result from relatively fast changes of the received pilots relative to the individual pilot components. | 12-18-2014 |
20140376917 | SYSTEMS AND METHODS FOR THE COMPENSATION OF NONLINEAR CROSS POLARIZATION AND CROSS PHASE MODULATION IN DUAL POLARIZATION COHERENT CHANNELS - The present disclosure provides systems and methods for the compensation of signal distortion in fiber optic communication systems and the like. More specifically, the present disclosure provides an orthogonal polarization detection and broadband pilot (OPDBP) technique for the compensation of nonlinear cross polarization (i.e. nonlinear cross polarization modulation) (XPolM) induced noise and nonlinear nonlinear cross phase modulation (XPM) induced noise in a high data rate polarization multiplexed (PM) multilevel-quadrature amplitude modulated (M-QAM) channel due to neighboring channels. This approach allows for the compensation of both XPolM and XPM simultaneously, providing several dBs of optical reach extension. The approach uses a pilot tone based orthogonal polarization detection scheme with broadband (i.e. a few GHz wide) filtering of the pilot tones. | 12-25-2014 |
20150030330 | OPTICAL TRANSMITTER, OPTICAL COMMUNICATION SYSTEM, AND OPTICAL COMMUNICATION METHOD - It becomes difficult to regenerate transmitting signals depending on modulation systems for the optical phase modulation in a polarization multiplexed optical communication system employing the optical digital coherent communication system, therefore, an optical transmitter according to an exemplary aspect of the invention includes first optical quadrature modulation means for performing a phase modulation on a first continuous light beam and outputting a first transmitting light beam; second optical quadrature modulation means for performing a phase modulation on a second continuous light beam belonging in the same frequency band as that of the first continuous light beam and outputting a second transmitting light beam; optical phase difference adding means for adding an optical phase difference varying temporally between the first transmitting light beam and the second transmitting light beam; and polarization multiplexing means for polarization-multiplexing the first transmitting light beam and the second transmitting light beam in the state where their polarizations are made to be orthogonal to each other and outputting a polarization multiplexed transmitting light beam. | 01-29-2015 |
20150030331 | NONLINEAR CROSS-POLARIZATION MITIGATION ALGORITHM - An exemplary technique is provided for a coherent optical receiver adapted to receive an optical signal transmitted over an optical transmission channel exhibiting Cross-Polarization Modulation (XPOLM). The received optical signal comprises a first polarization component and a second polarization component. The coherent optical receiver comprises a conversion and processing unit adapted to generate a set of digital signals based on the received optical signal; a polarization de-multiplexing unit adapted to de-multiplex the set of digital signals into a first complex component in a first polarization axis and a second complex component in a second polarization axis; and an XPOLM compensation unit adapted to transform the first and second complex components into Stokes space; determine a rotation of the first and second polarization axes; and determine XPOLM compensated first and second complex components by transforming the first and second complex components based on the determined rotation of the first and second polarization axes. | 01-29-2015 |
20150037034 | FLEXIBLE OPTIMIZATION OF THE SIGNAL-TO-NOISE RATIO FOR ULTRA DENSE COHERENT WDM SYSTEMS - The present document relates to optical communication systems. In particular, the present document relates to high efficiency wavelength division multiplexing (WDM) optical communication systems. An optical transmitter ( | 02-05-2015 |
20150050020 | OPTICAL TRANSCEIVER AND OPTICAL OUTPUT LEVEL CONTROL METHOD - A receiving-side integrated optical circuit of an optical transceiver has an optical wavelength demultiplexer to separate signal light components of the different wavelengths contained in a wavelength division multiplexed signal received from each of N links of a transmission path, a set of N optical amplifiers inserted between the transmission path and the optical wavelength demultiplexer, each optical amplifier being configured to collectively amplify the signal light components of the different wavelengths contained in the received wavelength division multiplexed signal, and a set of photo detectors arranged after the optical wavelength demultiplexer and to detect the signal light components of the different wavelengths. | 02-19-2015 |
20150063808 | IDENTIFYING DATA STREAMS IN POLARIZATION MULTIPLEXED TRANSMISSION - A polarization multiplexed receiver includes a polarization separator and optical mixing, detecting and analog-to-digital components. The polarization separator receives polarization multiplexed optical signals containing a first data stream and a second data stream, and operate upon the polarization multiplexed optical signals to separate, in an optical domain, the first data stream and the second data stream to generate a first optical output having the first data stream and a second optical output having the second data stream. The optical mixing, detecting and analog-to-digital converting components receive the first and second optical outputs from the polarization separator, extract, in a digital domain, the first data stream from the first optical output of the polarization separator, and extract, in the digital domain, the second data stream from the second optical output of the polarization separator. | 03-05-2015 |
20150063809 | OPTICAL MODULE AND OPTICAL TRANSMITTER - An optical module includes a waveguide substrate having an optical waveguide and electrodes that apply electronic signals to the optical waveguide; a relay substrate disposed adjacently to the waveguide substrate; and a termination substrate disposed sandwiching the waveguide substrate with the relay substrate. The electrodes respectively have a first wiring portion connected from the relay substrate through the waveguide substrate to the termination substrate and a second wiring portion extending from the first wiring portion and branching on the termination substrate. In the second wiring portion, one branched wiring portion has a capacitor and a termination resistor, and another branched wiring portion extends through a bias resistor to a DC electrode on the relay substrate. The second wiring portion is divided into a first group extending in a first direction along the optical waveguide and a second group extending in a direction opposite to the first direction. | 03-05-2015 |
20150063810 | OPTICAL 90-DEGREE HYBRID CIRCUIT AND OPTICAL RECEIVER USING SAME - An object of the present invention is to provide an optical 90-degree hybrid circuit which is capable of easily adjusting the optical power ratio between signal and local oscillator and suppresses an optical system of an optical receiver becoming complex and optical receivers using the same. The optical 90-degree hybrid circuit for demodulating multilevel phase-modulated signals corresponding to individual polarized waves by multiplexing an optical wave having a predetermined plane of polarization contained in signal and local oscillator that has the same wavelength as the signal and has been adjusted to circularly-polarized signal, and polarization-splitting the multiplexed signal includes polarization splitting means (polarization splitting) for extracting an optical wave having a predetermined plane of polarization from the signal, a polarization conversion element for rotating a plane of polarization of the optical wave extracted from the polarization splitting means, and a polarizer that determines a plane of polarization of the signal before multiplexing the signal with the local oscillator, and the polarization splitting means, the polarization conversion element, and the polarizer adjust intensity of the optical signal (VOA function) in cooperation with each other. | 03-05-2015 |
20150078749 | PLANAR LIGHTWAVE CIRCUIT AND OPTICAL RECEIVER - A planar lightwave circuit includes a substrate in which a groove being formed, the groove dividing the substrate into a first area and a second area; a first filter, a second filter, and a third filter intruded into the groove; as are formed in the first area, a first and a second waveguides formed to guide signal light and local oscillation light; a third and a fourth waveguides formed to guide signal light and local oscillation light; a first 90-degree optical hybrid; as are formed in the second area, a fifth and sixth waveguides formed to guide signal light and local oscillation light; and a second 90-degree optical hybrid. | 03-19-2015 |
20150086204 | FREQUENCY-DIVERSITY MIMO PROCESSING FOR OPTICAL TRANSMISSION - An optical transport system configured to transmit information using two or more modulated optical carriers spaced at spectral intervals that are smaller than the baud rate. An example optical receiver in the optical transport system includes a signal equalizer configured to implement frequency-diversity multiple-input/multiple-output signal processing directed at canceling the effects of inter-carrier interference caused by the spectral overlap between adjacent modulated optical carriers to enable the optical receiver to recover individual data streams encoded onto the different modulated optical carriers at the corresponding optical transmitter(s). Some embodiments of the optical transport system may advantageously be capable of achieving a higher spectral efficiency than the spectral efficiency supported by the optical orthogonal-frequency-division-multiplexing transmission format. | 03-26-2015 |
20150110490 | RECEIVER, TRANSMISSION SYSTEM, METHOD FOR RECEIVING POLARIZATION MULTIPLEXED OPTICAL SIGNAL, AND NON-TRANSITORY COMPUTER READABLE MEDIUM STORING RECEIVER CONTROL PROGRAM - In a receiver, a reception front end receives a polarization-scrambled polarization multiplexed optical signal, polarization-separates the received polarization multiplexed optical signal, and converts each signal into quantized signals. A digital signal processor samples the quantized signals, demodulates the signals by using a polarization separation digital signal processing algorithm, and outputs demodulated signals. When phase and amplitude variations of the demodulated signals are greater than a predetermined value, a control circuit causes the digital signal processor to interrupt processing using the polarization separation digital signal processing algorithm, changes an initial value of a filter coefficient, and then causes the digital signal processor to start the processing using the polarization separation digital signal processing algorithm. | 04-23-2015 |
20150125150 | OPTICAL RECEIVER AND OPTICAL RECEIVING METHOD - An optical receiver, includes: a signal processor to perform digital signal processing on a polarization demultiplexed signal obtained by demultiplexing a polarization multiplexed signal corresponding to a reception signal, the signal processor includes: an adaptive equalization circuit to compensate for the polarization demultiplexed signal by control of a filter coefficient; a first frequency offset estimation circuit to receive a first polarization demultiplexed signal diverged at a preceding stage and estimate a first frequency offset; a second frequency offset estimation circuit to receive a second polarization demultiplexed signal diverged at a succeeding stage and estimate a second frequency offset; and a decision circuit to decide whether the filter coefficient is correct based on a first difference between the first frequency offset and the second frequency offset and output, when deciding that the filter coefficient is incorrect, a first trigger for re-calculation of the filter coefficient. | 05-07-2015 |
20150131996 | OPTICAL RECEIVER, OPTICAL SIGNAL PROCESSING METHOD, AND OPTICAL TRANSMISSION SYSTEM - An optical receiver includes: an optical brancher configured to branch polarization multiplexed light to a first polarization multiplexed light and a second polarization multiplexed light, the polarization multiplexed light in which a pilot signal is superimposed on at least one of a first polarization and a second polarization; an optical fiber configured to transmit the first polarization multiplexed light; a first polarization rotator configured to control a first polarization state of the first polarization multiplexed light output from the optical fiber; a first polarization separator configured to separate the second polarization multiplexed light into a third polarization and a fourth polarization; and a controller configured to control the first polarization rotator based on one of a first pilot signal included in the third polarization and a second pilot signal included in the fourth polarization. | 05-14-2015 |
20150139648 | METHOD AND DEVICE FOR SIGNAL PROCESSING IN AN OPTICAL COMMUNICATION NETWORK - A method and a device for data processing in an optical communication network are provided, wherein in an energy saving mode of a polarization multiplexing system data signals are transmitted or received via one polarization plane; and wherein components of the transmitter or receiver of the other polarization plane are at least partially operated in a reduced power mode. Furthermore, a communication system is suggested comprising said device. | 05-21-2015 |
20150139649 | POLARIZATION MULTIPLEXING OPTICAL TRANSCEIVER - It is provided a polarization multiplexing optical transceiver including a polarization multiplexing optical transceiver, a polarization multiplexing optical receiver, a transmission side polarization state control unit and a reception side polarization state control unit. The polarization multiplexing optical receiver includes: a polarization demultiplexing unit; a plurality of information signal reconstruction units configured to receive the reconstructed polarization component on the transmission side as an input, and reconstruct and extract information signals; and an information signal coupling unit configured to one of couple and select the information signals output by the plurality of information signal reconstruction units and output the resultant under control of the reception side polarization state control unit. The polarization multiplexing optical receiver is configured to control, in the single polarization reception state, the polarization demultiplexing unit and at least a part of the plurality of information signal reconstruction units to transition to a power saving mode. | 05-21-2015 |
20150295658 | SINGLE-FIBER COUPLED MULTI-WAVELENGTH OPTICAL TRANSCEIVER MODULE - The present patent application discloses a single-fiber coupled multi-wavelength optical transceiver, comprising a fiber ferrule, a circulator subassembly, a multiplexer/demultiplexer subassembly, an optical transmitting subassembly and an optical receiving subassembly. The circulator subassembly comprises three ports. The optical transceiver comprises an optical receiving unit and an optical transmitting unit. The light beams of the optical receiving unit incidents from the fiber ferrule to the first port of the circulator, then output to multiplexer/demultiplexer through the second port of the circulator subassembly. The light beams is then split by the multiplexer/de-multiplexer and received by the receiver optical subassembly. | 10-15-2015 |
20150295672 | OPTICAL WAVELENGTH DEMULTIPLEXER HAVING OPTICAL INTERFERENCE FILTERS CONNECTED IN CASCADE - An optical wavelength demultiplexer includes a wavelength demultiplexing device, a first wavelength filter and a first- and second-stage wavelength sub-filters. The wavelength demultiplexing device demultiplexes an input light into a first wavelength band including wavelengths λ | 10-15-2015 |
20150295675 | OPTICALLY INTERCONNECTED CHIP, METHOD OF TESTING THE SAME, AND OPTICAL RECEIVER - An optically interconnected chip includes a first optical transmitter circuit, a first spot size converter connected by a first optical waveguide to the first optical transmitter circuit, a first optical receiver circuit, a second spot size converter connected by a second optical waveguide to the first optical receiver circuit, a rotator provided between the second spot size converter and the first optical receiver circuit and configured to rotate a direction of polarization of light propagating through the second optical waveguide by 45 degrees, and a splitter provided after the rotator and configured to separate the rotated light into components according to directions of polarization of the light, wherein the first spot size converter and the second spot size converter are coupled directly to each other on a wafer. | 10-15-2015 |
20150311669 | EXTERNAL CAVITY FABRY-PEROT LASER - Methods, systems, and apparatus, for an external cavity FP laser. In one aspect, an apparatus is provided that includes a FP laser diode; a Faraday rotator (FR) coupled to receive an optical output of the FP laser diode and that rotates a polarization of the optical output; an optical fiber coupled at a first end to receive the output of the FR; a WDM filter coupled to a second end of the optical fiber to receive the optical signal from the optical fiber; and a FRM coupled directly or indirectly to an output of the WDM filter, wherein an optical output of the WDM filter is partially reflected by the FRM such that the polarization of a reflected beam is rotated, and wherein the reflected optical signal then passes through the FR with its polarization being rotated by the FR before it is injected back into the FP laser diode. | 10-29-2015 |
20150318951 | Multi-Channel Optical Transmitter Assembly and Methods of Making and Using the Same - An optical multiplexer and methods of making and using the same are disclosed. The multiplexer generally includes a beam splitter and a polarization beam splitter. The beam splitter is generally configured to combine first and second polarized optical signals by reflecting a first polarized optical signal towards a first target and allowing a second polarized optical signal to pass through towards the first target. The polarization beam splitter is generally configured to combine the first and second polarized optical signals with a third polarized optical signal by either (i) reflecting the third polarized optical signal towards a second target and allowing the first and second polarized optical signals to pass through towards the second target, or (ii) reflecting the first and second polarized optical signals towards the second target and allowing the third polarized optical signal to pass through towards the second target. | 11-05-2015 |
20150318952 | HYBRID OPTICAL TRANSMITTER AND/OR RECEIVER STRUCTURE - A device may include a substrate. The device may include a carrier mounted to the substrate. The device may include a transmitter photonic integrated circuit (PIC) mounted on the carrier. The transmitter PIC may include a plurality of lasers that generate an optical signal when a voltage or current is applied to one of the plurality of lasers. The device may include a first microelectromechanical structure (MEMS) mounted to the substrate. The first MEMS may include a first set of lenses. The device may include a planar lightwave circuit (PLC) mounted to the substrate. The PLC may be optically coupled to the plurality of lasers by the first set of lenses of the first MEMS. The device may include a second MEMS, mounted to the substrate, that may include a second set of lenses, which may be configured to optically couple the PLC to an optical fiber. | 11-05-2015 |
20150333840 | PHOTON SOURCE - A photon source comprising a quantum structure capable of defining one or more quantum levels such that a photon may be emitted from the quantum structure due to a transition between at least two quantum levels,
| 11-19-2015 |
20150381279 | OPTICAL TRANSCEIVER AND COMMUNICATION SYSTEM - A communication system includes a termination-side optical transmitter comprising a reflective semiconductor optical amplifier, a reflective unit configured to reflect output light from the termination-side optical transmitter, and a terminal station-side optical receiver connected to the termination-side optical transmitter via a transmission line and configured to receive the output light from the termination-side optical transmitter by limiting a frequency band of the output light. The reflective semiconductor optical amplifier amplifies the output light reflected by the reflective unit, modulates the amplified output light based on an electric signal, and outputs the modulated output light. | 12-31-2015 |
20150381286 | OPTICAL RECEIVER FOR QUADRATURE-PHASE-SHIFT-KEYING AND QUADRATURE-DUOBINARY SIGNALS - We disclose an optical receiver that can receive PDM-QDB and PDM-QPSK signals without hardware changes. In an example embodiment, the optical receiver includes a MIMO equalizer configured to perform electronic polarization de-multiplexing and ISI compensation. The constant modulus algorithm that controls the configuration of the MIMO equalizer also causes the MIMO equalizer to output signal samples corresponding to the QPSK modulation format regardless of whether the received optical signal is QDB-modulated or QPSK-modulated. A QPSK-to-QDB constellation converter processes the signal samples generated by the MIMO equalizer to convert them into the QDB modulation format. A QDB decoder coupled to the constellation converter then recovers the data encoded in the received optical signal by mapping the processed signal samples onto the QDB constellation. Differential encoding used at the corresponding remote transmitter enables the decoder to correctly recover the encoded data both when the received optical signal is QDB-modulated and QPSK-modulated. | 12-31-2015 |
20160006507 | OPTICAL COMMUNICATION SYSTEMS AND METHODS - Systems and methods presented herein provide for optical communications with a remotely located laser. In one embodiment, a communication system includes an optical link and a communication hub comprising at least two lasers optically coupled to a first end of the optical link, the communication hub further comprising an optical multiplexer operable to multiplex light from the lasers and to propagate the multiplexed light along the optical link. The communication system also includes a communication node comprising an optical modulator optically coupled to a second end of the optical link, wherein the optical modulator is operable to modulate the multiplexed light from the communication hub with one or more modulating signals, and to propagate the modulated light to the communication hub. | 01-07-2016 |
20160006512 | OPTICAL TRANSMISSION DEVICE - Provided is an optical transmission device for transmitting and receiving a multilevel-modulated optical signal, including: a plurality of transmission frame processors ( | 01-07-2016 |
20160006537 | WAVELENGTH DIVISION MULTIPLEXING OPTICAL TRANSMISSION APPARATUS AND WAVELENGTH DIVISION MULTIPLEXING OPTICAL TRANSMISSION METHOD - A wavelength division multiplexing optical transmission apparatus includes a plurality of polarization multiplexing optical modulation means, polarization-maintaining optical multiplexing means, and delay adjustment means. The polarization multiplexing optical modulation means generate a plurality of polarization multiplexed optical modulation signals having different wavelengths. The polarization-maintaining optical multiplexing means multiplexes the wavelengths of the polarization multiplexed optical modulation signals to generate a wavelength multiplexed optical signal (WDM). The delay adjustment means adjusts a delay such that light intensities of polarization multiplexed optical modulation signals having adjacent wavelengths in the wavelength multiplexed optical signal (WDM) vary inversely with respect to each other. | 01-07-2016 |
20160006538 | OPTICAL TRANSMISSION APPARATUS AND OPTICAL TRANSMISSION METHOD - An optical transmission apparatus includes: an optical transmitter; and an optical receiver. The optical transmitter has a plurality of modulation rules, switches the plurality of modulation rules to generate optical signals, multiplexes the optical signals with orthogonal polarizations, randomizes phases of the optical signals, and transmits the optical signals. The optical receiver includes: a coherent detector for causing interference between received optical signals and local oscillation light to convert the optical signals into electrical signals; a polarization splitter and adaptive equalizer for subjecting the electrical signals to polarization splitting and adaptive equalization; and decoders for performing decoding or differential detection on the electrical signals on which polarization splitting and adaptive equalization have been performed. | 01-07-2016 |
20160013882 | TRANSMISSION/RECEPTION DEVICE, OPTICAL SPACE TRANSMISSION SYSTEM, AND TRANSMISSION/RECEPTION METHOD | 01-14-2016 |
20160036554 | SIGNAL PROCESSING DEVICE AND SIGNAL PROCESSING METHOD - An optical reception device | 02-04-2016 |
20160043803 | High-RF-Frequency Analog Fiber-Optic Links using Optical Signal Processing Techniques - Wide band phase modulators used with high power laser carriers convert high-frequency RF signals to phase-modulated optical signals. Higher laser optical power to the modulator produces larger RF signal sidebands. A carrier attenuation filter passes the attenuated carrier and non-attenuated RF modulation sidebands. Carrier attenuation leaves the larger RF signal sidebands. A demodulation filter used with a photodetector or a balanced photodetector pair converts the phase-modulated optical signal back to an electrical signal. Carrier-only attenuation allows high power laser use, avoids photodetector damage or saturation, and provides increased RF link gain, low noise figure (NF) and high spurious-free dynamic range (SFDR). Filtered-out carrier power fed back to the laser source increases to overall system efficiency. An additional optical delay filter with dual outputs used with a polarization multiplexer or a coherent combiner coupler combines signal power to a single photodetector to further increase electro-optic signal conversion efficiency. | 02-11-2016 |
20160050025 | SIGNAL PROCESSING DEVICE, OPTICAL COMMUNICATION SYSTEM, AND SIGNAL PROCESSING METHOD - An optical receiver ( | 02-18-2016 |
20160065325 | MUXPONDER AND METHOD OF CONVERTING A PLURALITY OF TRIBUTARY OPTICAL COMMUNICATIONS SIGNALS HAVING A FIRST BIT RATE INTO AN OPTICAL LINE SIGNAL HAVING A SECOND, HIGHER BIT RATE - A muxponder comprising: modulation format conversion apparatus comprising:
| 03-03-2016 |
20160065326 | OPTICAL TRANSMISSION/RECEPTION SYSTEM, TRANSMITTER, RECEIVER, AND OPTICAL TRANSMISSION/RECEPTION METHOD - An optical transmission and reception system includes a transmitter and receiver. The transmitter differentially encodes control information to generate a differentially coded signal; uses the differentially coded signal to modulate a signal sequence in which electricity concentrates at a particular frequency; applies time-division multiplexing on the modulated signal sequence and a primary signal in one of two polarized wave components, and applies time-division multiplexing on the other polarized wave components and the signal sequence itself; and polarization-multiplexes the both of the time-division multiplexed polarized waves into an optical signal; and transmits the optical signal to the receiver. The receiver polarization-demultiplexes the received optical signal to generate two polarized wave signals; extracts the signal sequence in which electricity concentrates at the particular frequency from the two polarized wave signals; and applies differential detection on the extracted signal sequence to demodulate the control information. | 03-03-2016 |
20160080084 | DIGITAL OPTICAL SPECTRAL SHAPING - A method and system for generating an optical channel signal for transmission through an optical fiber link of an optical communications system. A digital filter processes an input data signal using a compensation function and a shaping function to generate a pair of multi-bit sample streams representing a target optical E-field envelope of the optical channel signal. A modulator modulates an optical carrier light using the pair of multi-bit sample streams to generate the optical channel signal. The compensation function is designed to at least partially compensate impairments of the optical fiber link. The predetermined shaping function is designed to modify a baseband spectrum of the target optical E-field envelope. | 03-17-2016 |
20160085024 | Optical Spatial Mode-Multiplexer - An apparatus includes an optical fiber bundle that includes a plurality of input optical fibers and a tapered segment. One end of each of the input optical fibers physically connects to a wide end of the tapered segment. The optical fiber bundle is an integral unit. The input optical fibers are multimode optical fibers. Fundamental optical propagating modes of at least two of the multimode optical fibers have different velocities. | 03-24-2016 |
20160087751 | Linear Dispersion Polarization-Time Codes and Equalization in Polarization Multiplexed Coherent Optical System - A method of optical communication comprising encoding four modulated symbols to generate four encoded symbols in two orthogonal polarizations and transmitting the four encoded symbols in two successive time slots. An optical communication apparatus comprising a processor configured to receive two sequences of digital symbols in a plurality of time slots, wherein the two sequences correspond to two components of two orthogonal polarizations, wherein one digital symbol per polarization is received in each of the plurality of time slots, divide each of the two sequences into a plurality of groups using a modulo operation of time, wherein each group comprises two digital symbols received in two consecutive time slots, and adaptively equalize the four digital symbols of the two consecutive time slots using a 4×4 matrix to generate four modulated symbols, wherein the 4×4 matrix comprises 16 tap-vectors. | 03-24-2016 |
20160112143 | BLIND EQUALIZATION OF DUAL SUBCARRIER OFDM SIGNALS - A dual-polarization, 2-subcarriers code orthogonal, orthogonal frequency division multiplexed signal carrying information bits is transmitted in an optical communication network without transmitting a corresponding pilot tone or training sequence. A receiver receives the transmitted signal and recovers information bits using a blind equalization technique and by equalizing the 2-subcarriers OFDM signal as a 9-QAM signal in time domain with a CMMA (constant multi modulus algorithm) equalization method. | 04-21-2016 |
20160119078 | MULTICHANNEL DATA TRANSPORT SUITABLE FOR DIRECT OPTICAL DETECTION AT THE RECEIVER - We disclose an optical transport system configured to transport the same data using two different channels of an optical transport link in a manner that enables an optical receiver to use direct detection of the optical power received through each of the two channels to measure the in-phase and quadrature components of the modulating electromagnetic field. In an example embodiment, an optical carrier of the modulated optical signal transported using the first of the two channels and an optical carrier of the modulated optical signal transported using the second of the two channels have a fixed relative phase offset of approximately 90 degrees. The resulting ability of the optical receiver to measure each of the in-phase and quadrature components of the modulating electromagnetic field advantageously enables the optical receiver to perform electronic signal equalization, including but not limited to electronic dispersion compensation. | 04-28-2016 |
20160134391 | METHOD OF OPTICAL DATA TRANSMISSION USING POLARIZATION DIVISION MULTIPLEXING AND QPSK - Proposed is a method of optical data transmission. The method comprises different steps. At least one stream of data bits is received. Sets of data bits are mapped onto successive logical states. The logical states correspond to respective sets of two initial QPSK symbols chosen according to a QPSK mapping and according to a set partitioning rule. The logical states are differentially encoded according to a differential encoding rule. For the differentially encoded logical states respective sets of two resulting QPSK symbols are derived according to the QPSK mapping and according to the set partitioning rule. The encoded sets of two QPSK symbols are transmitted using polarization division multiplexing. The differential encoding rule results in a differential encoding of one of the initial QPSK symbols but not the other of the initial QPSK symbols. | 05-12-2016 |
20160142149 | System and Methods for Adaptive Equalization for Optical Modulation Formats - A method for modifying the performance of an adaptive equalizer in a receiver is provided. A carrier wave comprising a first polarization state and a second polarization state, wherein there is a correlation between the first polarization state and the second polarization state, is received. The first polarization state and the second polarization state are demultiplexed to generate two respective constellations. A first expected value based on the first constellation, and a second expected value based on the second constellation, are calculated. An adaptive equalizer receives a first and second signals associated with the respective polarization states. The adaptive equalizer generates outputs based on the signals. These outputs are used to generate error values. Feedback is input into the adaptive equalizer, wherein the feedback is based on the error values. | 05-19-2016 |
20160142179 | Optimization of Optical Transmission Capacity - A method for transmitting a coherent optical data signal includes receiving a data signal from an interface, and encoding the data signal with a forward error correcting (FEC) encoder according to a mix of modulation formats. The FEC encoder generates an FEC encoded signal which is used to generate modulation symbols according to the modulation formats. The FEC encoded signal of modulation symbols is spectrally shaped to generate a shaped signal, and pre-distorted before transmission. The shaped signal is pre-distorted by adding a predetermined amount of chromatic dispersion to generate a smoothed signal, and the smoothed signal is transmitted according to the modulation formats. | 05-19-2016 |
20160147018 | Device and Method for Optical Beam Combination - An optical apparatus includes a first beam combining device arranged to receive a first optical beam having a first wavelength at a first location and a second optical beam output having a second wavelength at a second location. The second optical beam has a polarization that is substantially orthogonal to a polarization of the first optical beam. The first beam combining device configured to output a first combined beam that comprises a combination of the first optical beam and the second optical beam. An optical element is arranged to receive the first combined beam and a second combined beam and to transmit an output beam that includes a combination of the first combined beam and the second combined beam. | 05-26-2016 |
20160182182 | POLARIZATION TRACKING USING SIGNAL TONE INFORMATION WHILE KEEPING LEAST MEAN SQUARES FREQUENCY DOMAIN EQUALIZATION | 06-23-2016 |
20160191169 | OPTICAL MODULATOR AND OPTICAL TRANSMITTER - An optical modulator includes a package that accommodates therein a first substrate and a second substrate different from the first substrate, and outside the package, a flexible circuit board. The first substrate has plural optical modulating units disposed thereon in parallel and each including a Mach-Zehnder optical waveguide. Plural first signal line paths corresponding to the optical modulating units are disposed on the second substrate. Plural second signal line paths corresponding to the optical modulating units are disposed on the flexible circuit board. Electrical lengths of the second signal line paths are different from one another. Electrical lengths of signal paths that span from input ends of the second signal line paths corresponding to the optical modulating units to base points on signal electrodes, via the first signal line paths, are equal to one another. | 06-30-2016 |
20160195792 | DEVICE AND METHOD FOR ALL-OPTICAL INFORMATION EXCHANGE | 07-07-2016 |
20160204894 | STOKES-VECTOR-BASED TRANSMISSION AND DETECTION OF OPTICAL POLARIZATION-DIVISION-MULTIPLEXED SIGNALS | 07-14-2016 |
20160204896 | TIME DIVISION MULTIPLEXED ORBITAL ANGULAR MOMENTUM BASED COMMUNICATION | 07-14-2016 |
20160380716 | METHOD AND SYSTEM FOR REMOVING A PILOT TONE FROM AN OPTICAL SIGNAL - The present applies to digital wavelength converters that convert, independently of the format in which optical data may be encoded, an input waveform at a first wavelength to an output waveform at a second wavelength. When operating in an environment where an input waveform has a pilot tone associated thereto, the method and system of the present disclosure allows for the removal of the pilot tone from the input waveform, and also allows for the addition of another pilot to the output waveform. | 12-29-2016 |
20170237519 | EXTERNAL CAVITY FP LASER | 08-17-2017 |