Class / Patent application number | Description | Number of patent applications / Date published |
398188000 | Phase modulation | 67 |
20080199189 | COLORLESS OPTICAL DEMODULATOR FOR DIFFERENTIAL QUADRATURE PHASE SHIFT KEYING DWDM SYSTEMS - A colorless optical DQPSK demodulator and system operating over multiple, equally-spaced DWDM channels with fixed optical delays—capable of demodulating DQPSK within signals within DWDM communications wave bands on ITU grids using delay interferometers having fixed free spectral range at 20 GHz or 25 GHz. | 08-21-2008 |
20090041473 | Optical device, optical modulation method, and optical transmitter - An optical modulation device including waveform shapers that waveform-shape input data signals in synchronism with a rising or falling timing based on comparison with a reference level of an input clock signal, a multi-level phase modulator that generates a multi-level-phase-modulated optical signal based on the data signals waveform-shaped by the plurality of waveform shapers, and outputs the generated optical signal, and a level ratio controller that varies a relative level ratio of the reference level to an amplitude level of the clock signal input to the waveform shapers, based on the optical signal output from the multi-level phase modulator. | 02-12-2009 |
20090047028 | QUADRATURE PHASE-SHIFT KEYING MODULATOR AND PHASE SHIFT AMOUNT CONTROLLING METHOD FOR THE SAME - The improved quadrature phase shift keying modulator has a structure such that the average light output power of phase-shift keying modulation light output from the combining unit is changed according to the phase difference between the first and the second optical signal after being combined by means of applying driving signals different in eye crossing percentage by the first modulator and the second modulator, respectively, and has a power monitor monitoring the average light output power of quadrature phase-shift keying modulated light and a phase shift controlling unit which performs feedback control of the phase shift amount in the phase shifting unit based on the average light output power monitored by the power monitor. | 02-19-2009 |
20090097864 | SYSTEMS AND METHODS FOR PHASE CONTROL FOR RZ-DQPSK MODULATION - RZ-DQPSK (Return-to-Zero Differential Quadrature Phase Shift Keying) systems and methods are provided with a single real-time phase alignment mechanism. The present invention eliminates the requirement for phase adjustment between a carver modulator and a DQPSK modulator. In an exemplary embodiment, the present invention replaces the carver modulator with AND gates between drivers of a DQPSK modulator and a data processor. The AND gates are configured to provide a single phase alignment signal. | 04-16-2009 |
20090116849 | DQPSK modulation apparatus and DQPSK modulation method - An optical transmitting apparatus includes a branching unit that branches light output from a light source into light beams, a phase control unit and an ABC circuit that control the phase of one of the light beams to π/2, a data processing unit that performs phase modulation on each of the light beams, phase modulating units, an interfering unit that makes the light beams on which the phase modulation has been performed interfere with each other, and a signal-generation control unit that changes the phase amount from π/2 by an amount corresponding to a desirable penalty amount. | 05-07-2009 |
20090123164 | Wave-division multiplexing telecommunications system and method - A fiber optic data transmission system includes an optical fiber and a data transmitter having a first laser having a first wavelength, a first phase modulator for phase modulating light from the first laser as a function of a first data input stream so as to create a first phase-modulated output data stream, a second laser having a second wavelength different from the first wavelength, and a second phase modulator for phase modulating light from the second laser as a function of a second data input stream so as to create a second phase-modulated output data stream. The transmitter also includes a combiner combining the first and second output data streams into a phase-modulated optical signal for transmission over the optical fiber. | 05-14-2009 |
20090136241 | OPTICAL MSK DATA FORMAT - A method of generating an optical minimum shift keying (MSK) modulated signal, a method of pre-coding an input data stream for generation of an optical MSK modulated signal, a method of decoding an optical MSK modulated signal, an MSK transmitter, an encoder structure for encoding an input data stream for generation of an optical MSK modulated signal, and a receiver structure for decoding an optical MSK modulated signal. The method of generating an optical minimum shift keying (MSK) modulated signal comprises amplitude modulating a first optical signal utilising a clock signal having a clock frequency to generate a carrier suppressed return-to-zero (CS-RZ) second optical signal; splitting the second optical signal into a third and a fourth optical signals in a first arm and a second arm respectively; applying a substantially 1-bit time delay in the first arm and applying a phase shift in the second arm such that a phase difference between the first and second arms is π/2; applying phase modulation in the first and second arms according to respective bit sequences; and combining the third and fourth signals from the first and second arms into the optical MSK modulated signal. | 05-28-2009 |
20090202257 | OPTICAL TRANSMISSION APPARATUS AND SYSTEM - Disclosed is an optical fiber transmission system for transmitting an optical signal by DPSK modulation includes a plurality of NZ-DSF (Non-Zero Dispersion Shifted single-mode optical Fiber) transmission line blocks, each of which has N spans of a span comprising a serially connected NZ-DSF and optical repeater, and one span that includes a dispersion compensating fiber and an optical repeater. The average wavelength dispersion value of each NZ-DSF transmission line block is made non-zero. | 08-13-2009 |
20090214224 | METHOD AND APPARATUS FOR COHERENT ANALOG RF PHOTONIC TRANSMISSION - A system for high fidelity analog RF photonic communications is disclosed wherein linear phase modulation and linear coherent demodulation is included. A single optical beam with a phase-modulated signal optical carrier combined with an orthogonally polarized reference unmodulated optical carrier is transmitted simultaneously. At the receiver, the polarization of the reference carrier is transform to match that of the signal followed by coherent detection. An in-phase and quadrature-phase component of the homodyne signal is generated where they are digitized and processed to recover the original RF signal. | 08-27-2009 |
20090245813 | Modulator driver with multi-channel active alignment - Modulator driver for driving an electro-optical modulator in a high-speed optical communications system. In accordance with aspects of the present invention, a modulator driver is presented comprising an active signal splitter providing a first pair and a second pair of differential output signals, each pair of differential output signals input to a separate variable delay circuit, each variable delay circuit in turn feeding an output buffer, whereby one signal from each output buffer is used as an output drive signal, and the other signal from each output buffer is input to a phase processor which is used to actively control said variable delay circuits, whereby the circuit architecture is compatible with compact, monolithic fabrication requiring a minimal amount of external components for operation. Other methods and apparatus are presented. | 10-01-2009 |
20090245814 | OPTICAL COMMUNICATIONS - A method of transmitting a plurality n data streams comprises modulating an optical carrier using differential M-ary phase shift key (DMPSK) signalling in which M=2 | 10-01-2009 |
20090252502 | METHODS AND SYSTEMS FOR OPTICAL COMMUNICATION - An optical communication system includes an optical carrier signal source that provides an optical carrier signal and one or more optical modulators coupled to the optical carrier signal source. The optical modulators modulate the optical carrier signal to produce a continuous wave optical signal in response to one or more input electrical signals. The system also includes a pulse modulator coupled to the optical modulators. The pulse modulator adaptively modulates the continuous wave optical signal to cause carrier energy suppression and nonlinearity reduction. In a specific embodiment, the pulse modulator modulates the continuous wave optical signal in response to al pulse signal, which is characterized by an amplitude and a bias point. At least one of the amplitude and the bias point being adaptively determined to cause carrier energy suppression and nonlinearity reduction. Additionally, the system can also include an optical spectral monitor for modulator bias stabilization. | 10-08-2009 |
20090269080 | OPTICAL TRANSMITTING APPARATUS - An optical transmitting apparatus includes a modulating unit that branches an input light and performs independent phase modulation to branched optical signals of arms, a phase adjusting unit that changes a phase difference between the optical signals of respective arms according to a control signal, a combining unit that combines modulated lights having the phase difference, an acquiring unit that acquires a positive-phase signal and a negative-phase signal from the combining unit, a subtracting unit that obtains a difference between the positive-phase signal and the negative-phase signal acquired by the acquiring unit, a detecting unit detecting a power of a differential signal from subtraction by the subtracting unit, and a control unit that changes the control signal according to signal component intensity detected by the detecting unit. | 10-29-2009 |
20090304394 | DELAY INTERFEROMETER - In a delay interferometer in which a Michelson delay interferometer unit is mounted in a package, the delay interferometer includes a Michelson delay interferometer unit which outputs first interference output light from a first output port, the first interference output light being obtained by optically processing input light received through an input port by a beam splitter and reflectors, and which outputs second interference output light from a second output port, and the splitting portion and the beam splitter are integrally structured. | 12-10-2009 |
20100021182 | OPTICAL TRANSMITTER - An optical transmitter includes a modulation unit, an optical coupler, a photodetector and a control unit. The modulation unit sets up a phase difference between first and second optical signals acquired by branching an input light. The modulation unit modulates the first and second optical signals based on first and second input data signals, respectively. The optical coupler couples the first and second optical signals to generate a phase-modulated optical signal. The photodetector generates a received signal based on the phase-modulated optical signal. The control unit superimposes a dither signal having a frequency on at least one of the first and second optical signals. The control unit performs detection on the dither signal that is included in the received signal output from the photodetector. The control unit controls the phase difference that is to be set up by the modulation unit. The control of the phase difference is made based on a result of the detection. | 01-28-2010 |
20100067923 | Optical M-ary modulator - An optical m-ary modulator includes an optical loop forming a polarization maintaining closed optical path. A loop input-output unit splits linearly polarized input signal light into a first component and a second component and feeds the first and second components into the optical loop in opposite directions. A pair of phase modulators modulate the first and second components according to respective control signals. The loop input-output unit recombines the modulated first and second components. The optical phase bias unit creates a phase difference between the first and second components so that they combine to form an m-ary modulated optical signal. Since the first and second components travel around the same optical path, when they recombine their phases are correctly aligned, making the modulator immune to environmental effects and permitting the use of high-speed optical modulation techniques. | 03-18-2010 |
20100086314 | Method and Apparatus for an Optical Duty Cycle for an Optical Digital Coherent System - An optical apparatus includes a quadrature phase shift keying modulator for generating a non-return-to-zero quadrature phase shift keyed NRZ-QPSK signal from a received lightwave, the modulator being driven by a radio frequency RF signal, an intensity modulator for carving the NRZ-QPSK signal to return-to-zero RZ pulses with a different duty cycle than that of the NRZ-QPSK, the intensity modulator being driven by a radio frequency RF clock signal to change the NRZ-QPSK to an RZ-QPSK signal, and an optical filter with a narrow band for filtering the signal from the intensity modulator to increase optical power that is useable by an optical digital coherent detection system. | 04-08-2010 |
20100098435 | OPTICAL TRANSMITTER APPARATUS - An optical DQPSK modulator comprises a pair of phase modulators. Each of the pair of the phase modulators is provided with first and second driving signals. The first and second driving signals are amplified by first and second amplifiers, respectively. An RZ intensity modulator generates an optical RZ-DQPSK signal from an optical DQPSK signal output from the optical DQPSK modulator. A photodetector generates a monitor signal from the optical RZ-DQPSK signal. A gain adjuster unit adjusts the gains of the first and second amplifiers so as to minimize the power of the monitor signal. | 04-22-2010 |
20100129088 | OPTICAL TRANSMISSION APPARATUS - An optical transmission apparatus includes a Mach-Zehnder modulator, transmission lines which transmit modulation data to the Mach-Zehnder modulator, a phase varying section which is connected to at least one of the transmission lines, and a phase synchronization loop which is connected to the phase varying section, and which applies a control voltage on which a dither signal is superimposed to the phase varying section. The phase varying section adjusts a skew between the transmission lines to remain constant, based on the control voltage on which the dither signal is superimposed. | 05-27-2010 |
20100135674 | COMPLEX OPTICAL MODULATION FOR REAL TIME COMMUNICATION - Systems and methods for complex optical modulation for real time communication are provided. In one embodiment, a method for real time optical transmission of communications data comprises: generating first in phase (I) and quadrature phase (Q) components of from a first serial bit stream of digitized radio frequency (RF) samples, wherein the digitized RF samples carry a payload of samples of an RF carrier signal which has been modulated with baseband data; modulating an optical signal based on the in phase (I) and quadrature phase (Q) components to produce a complex modulated optical signal; transmitting the complex modulated optical signal over a fiber optic connection; demodulating in real time, second in phase (I) and quadrature phase (Q) components from the complex modulated optical signal; and generating a second serial bit stream of digitized RF samples from the second in phase (I) and quadrature phase (Q) components. | 06-03-2010 |
20100150576 | OPTICAL TRANSMITTING APPARATUS FOR RETURN-TO-ZERO DIFFERENTIAL PHASE-SHIFT-KEYING (RZ-DPSK) OR RETURN-TO-ZERO DIFFERENTIAL QUADRATURE PHASE SHIFT KEYING (RZ-DQPSK) - An optical transmitting apparatus is disclosed. The optical transmitting apparatus outputs a signal having the same phase characteristics as a Return-to-Zero Differential Phase-Shift-Keying (RZ-DPSK) signal by using a single phase modulator. Accordingly, it is possible to generate RZ-DPSK signals without using a separate RZ modulator. | 06-17-2010 |
20100150577 | Communication System and Method With Signal Constellation - An example method includes modulating an optical signal using a Phase Shift Keying (PSK) signal constellation, wherein signal points of the PSK signal constellation are located on at least two rings. The first ring has a first radius r | 06-17-2010 |
20100254715 | Driving method and driving apparatus for optical modulator, and optical transmitter using same - A driving apparatus supplies a drive signal to an optical modulator corresponding to a phase modulation format, and also, divides a part of an output light from the optical modulator; extracts some optical component of the divided light, which is distant from a carrier frequency by integral multiple of a modulation frequency, to detect a power of the optical component; and feedback controls a duty ratio of the drive signal or a cross-point level thereof so that the detected power approaches a minimum value. Thus, it is possible to stably perform phase modulation with high precision. | 10-07-2010 |
20100254716 | Control apparatus and control method for optical modulator - An object of the invention is to provide a control system in which the phase shift between drive signals of an optical modulator can be reliably detected and compensated by a simple configuration. To this end, a control apparatus of the invention, for an optical modulator generating a signal light of a CS-RZ modulation system or the like by two LN modulators connected in series, detects the phase shift between drive signals given to the former and latter stage LN modulators, or judges the phase shift between the drive signals based on intensity information of the electric spectrum of the signal light output from the optical modulator, to control the phases of the drive signals so as to minimize the phase shift. As a result, the phase shift between the drive signals can be reliably detected and compensated by an electric circuit with a simple configuration. | 10-07-2010 |
20100329696 | 16 Quadrature Amplitude Modulation Optical Signal Transmitter - An optical transmitter including a dividing optical coupler for dividing a lightwave onto optical paths; a first optical modulator in a first of the optical paths and driven by an I component of a first signal and a I component of a second signal for modulating the lightwave, a DC bias of the first optical modulator being at a quadrature point; a second optical modulator in a second of the optical paths and driven by a Q component of the first signal and a Q component of the second signal for modulating the lightwave, a DC bias of the second optical modulator being at the quadrature point; a phase shifter for generating a 90 degree phase shift in the Q components of the first and second signals that are modulated by the second optical coupler; and a combining optical coupler for combining the modulated lightwave from the first optical coupler and the phase shifted Q components of the first and second signals for generating a quadrature amplitude modulated signal. | 12-30-2010 |
20110008057 | Rate Adjustable Differential Phase Shift Key (DPSK) Modulation - In a fixed delay optical communication system, rate adjustable differential phase shift key (DPSK) techniques eliminate the need for multiple comparing modules, each corresponding to a different data rate. Setting alternative data rates at integer multiples of the fundamental data rate of the optical communication system allows the system to process the respective integer number of symbols per period of the system, wherein the period of the system is the inverse of the fundamental data rate. Pulse carving techniques may be used to set the duty cycle of clock levels associated with a clock signal. The clock levels may be combined with respective symbols to provide optical symbols having a duty cycle less than 100%. | 01-13-2011 |
20110008058 | OPTICAL COMMUNICATIONS SYSTEM - The present invention relates to an optical communications system equipped with a structure, capable of applying a PBGF as an optical transmission line, by which high capacity information transmission is enabled by use of the PBGF. The optical communications system ( | 01-13-2011 |
20110038640 | SPECTRALLY EFFICIENT DIGITAL DATA TRANSMISSION UTILIZING PHASE ENCODED MMW - A digital data transmission device is provided comprising optical waveguide architecture, a sideband generator, a modulation controller, an optical filter, a data mapping unit, and a phase controller. The optical waveguide architecture is configured to direct an optical signal through the sideband generator and the optical filter. The sideband generator comprises an electrooptic interferometer comprising first and second waveguide arms. The modulation controller is configured to generate an electrical drive signal to drive the sideband generator at a control voltage that is substantially larger than Vπ to generate optical frequency sidebands about a carrier frequency of the optical signal. The optical filter is configured to discriminate between the optical frequency sidebands and the optical carrier frequency such that optical sidebands of interest can be directed through the optical waveguide architecture as an optical millimeter wave signal. The data mapping unit is configured to generate an encoded data signal representing a digital data input received by the data mapping unit. The phase controller is configured to alter the phase of the electrical drive signal in response to the encoded data signal generated by the data mapping unit. The sideband generator is configured such that encoded alterations in the phase of the electrical drive signal are manifested as encoded alterations in the phase of the optical millimeter wave signal, creating an encoded representation of the digital data input in the optical millimeter wave signal. Methods of transmitting digital data are also provided. | 02-17-2011 |
20110081153 | METHOD AND DEVICE FOR GENERATING OPTICAL SIGNALS - The method includes: receiving a first Non Return to Zero (NRZ) data signal and a synchronous clock signal, and performing Return to Zero (RZ) processing to generate a first complementary RZ data signal pair; receiving a second NRZ data signal and a synchronous clock signal, and performing RZ processing to generate a second complementary RZ data signal pair; and modulating the first complementary RZ data signal pair and the second complementary RZ data signal pair on light to generate an RZ-Differential Quadrature Phase Shift Keying (RZ-DQPSK) optical signal. Through the method and device, RZ processing are performed on the NRZ data signals to generate the complementary RZ data signal pairs, and the complementary RZ data signal pairs are modulated on the light, thereby reducing the cost and the insertion loss of the entire device, lowering the requirements for input optical power and reducing the complexity of loop circuit control. | 04-07-2011 |
20110091221 | METHOD AND SYSTEM FOR SETTING TIMING OF PHASE MODULATION OF xPSK TRANSMITTER - A method is provided for setting a timing of phase modulation by a target phase modulator within an optical transmitter which performs 2 | 04-21-2011 |
20110150502 | HIGH-SPEED OPTICAL TRANSMITTERS USING CASCADED OPTICALLY INJECTION-LOCKED LASERS - Apparatus and method for increasing optical transmission bandwidth in response to chaining, in cascade, one or more slave lasers onto a master laser. Each laser is configured for optical injection locking (OIL) and each slave laser is locked onto the master laser. The first and each subsequent slave laser are detuned to tailor frequency characteristics of apparatus output. The transmitter can be scaled up by cascading additional injection-locked lasers together. The invention supports multiple compatible modulation formats, such as amplitude modulation (AM), phase modulation (PM), and frequency modulation (FM), for tailoring the output to the application of interest, while any type of laser can be used for the master and slave lasers. | 06-23-2011 |
20110229149 | OPTICAL TRANSMITTER SUPPLYING OPTICAL SIGNALS HAVING MULTIPLE MODULATION FORMATS - Consistent with the present disclosure, a compact transmitter is provided that can generate optical signals having different modulation formats depending on optical link requirements. Preferably, the transmitter includes a photonic integrated circuit having multiple lasers and modulators. A control circuit adjusts the drive signals supplied to the modulators such that optical signals having a desired modulation format may be output from the modulators. Thus, for example, the transmitter may be used to output optical signals having a modulation format suitable for long haul or submarine links, as well as for links having a shorter distance. Moreover, the same photonic integrated circuit may supply optical signals with different modulation formats, such that, for example, those optical signals that are dropped along a link, and thus travel a shorter distance, may have a first modulation format, while other optical signals that travel the entire length of the link may have a second modulation format that is more suited for longer distances. | 09-22-2011 |
20110255876 | OPTICAL TRANSMITTER - An optical transmitter for converting an input data series into an optical multi-level signal and for outputting the same, includes an LUT in which data for executing optical multi-level modulation is stored and from which first modulation data and second modulation data are output based on the input data series. A DAC converts the first modulation data by D/A conversion to generate a first multi-level signal. A DAC converts the second modulation data by D/A conversion to generate a second multi-level signal. A dual-electrode MZ modulator includes a first phase modulator for modulating light from a light source in accordance with the first multi-level signal and a second phase modulator for modulating light from the light source in accordance with the second multi-level signal, and combines an optical signal from the first phase modulator and an optical signal from the second phase modulator to output the optical multi-level signal. | 10-20-2011 |
20120082468 | LOOK-UP TABLE AND DIGITAL TRANSMITTER BASED ARCHITECTURE FOR FIBER NONLINEARITY COMPENSATION - Systems and methods are disclosed to process an optical signal with a pre-processing module to populate a non-linearity compensation look-up table based on a set of predetermined rules in a non-real-time off-line mode; and a transmitter applying said predetermined rules in real-time to multiple channel input data to generate a real-time symbol pattern, searching the look-up table with the real-time symbol pattern to determine a non-linearity compensation output, and modulating the optical signal with the compensation output. | 04-05-2012 |
20120189322 | FRAME FORMATTING FOR HIGH RATE OPTICAL COMMUNICATIONS - Methods, systems, and devices are described for formatting of data streams to be transmitted over fiber optic channels, and for processing received optical signals. A data transmission device may include a digital coding and modulation module that encodes a digital data stream, inserts unique words into the digital data stream, and modulates the encoded data stream and unique words onto optical channels for transmission over an optical fiber. A demodulation and decoding device may include a unique word identification module that identifies the unique words inserted in each optical channel stream, determines one or more characteristics of the plurality of optical channels based on the unique words, and provides the one or more characteristics to one or more other modules in the demodulator and decoding device. | 07-26-2012 |
20120207483 | Apparatus and Method for Control the Driving Amplitude of Differential Quadrature Phase Shift Keying Transmitter - The present invention discloses an apparatus and a method for controlling a driving amplitude of a DQPSK transmitter. The method includes: a DQPSK modulator modulating an optical signal emitted from a CW and without adding with modulated signal; a modulator feedback control unit is connected with a first bias point, a second bias point and a third bias point and controls the first bias point, the second bias point and the third bias point according to a part of the optical signal modulated by the DQPSK modulator; controlling the driving amplitude of a driver I according to temperature change of the driver I; controlling the driving amplitude of a driver Q according to temperature change of the driver Q. The present invention can be used to simplify complexity of the control circuit of the DQPSK transmitter, and therefore no extra optical signal-to-noise ratio cost would be created. | 08-16-2012 |
20120251129 | OPTICAL MODULATOR WITH LINEAR RESPONSE - Apparatuses and methods for modulating an optical signal are disclosed. One embodiment is a method comprising: phase modulating a slave laser which is injection locked to a master laser to produce an arcsine phase modulated optical signal, and combining the arcsine phase modulated optical signal with an output optical signal from the master laser. | 10-04-2012 |
20120301156 | OPTICAL TRANSMITTER SUBASSEMBLY - An optical transmitter subassembly of one embodiment includes a temperature controller, first to third bases, a laser diode, and an optical system. The temperature controller includes first and second plates, and temperature controlling elements put between the first and second plates. The first base has first and second regions, and is supported by the first plate. The second base is mounted on the first region. The third base is mounted on the second region. The laser diode is a tunable laser diode integrated with a Mach-Zehnder type optical modulator, and is mounted on the second base. The optical system is capable of fixing a wavelength of the laser diode and is mounted on the third base. Only a portion of the first base is mounted on the first plate. The portion of the first base includes the first region. | 11-29-2012 |
20130188969 | METHOD AND SYSTEM FOR MULTIPLE RESONANCE INTERFEROMETER - A multiple resonance interferometer structure includes an input port and a first arm coupled to the input port and including a first resonant structure. The multiple resonance interferometer also includes a second arm coupled to the input port and including a second resonant structure and an output port coupled to the first arm and the second arm | 07-25-2013 |
20130322892 | Integrated Optical Phased Array - An integrated optical phased array includes an input channel receiving an optical input signal, and a multitude of signal processing channels each adapted to supply an associated optical output signal along a first axis in response to the input signal. Each signal processing channel includes, in part, a phase modulator adapted to modulate the phase of the signal travelling through the channel, thereby to control or steer the output signal of the phased array. Each channel optionally includes first and second photo detection circuits respectively generating first and second detection signals. The first and second detection signals in each channel may be used to modulate the amplitude and/or phase of the output signal of that channel thereby to control and steer the output signal of the phased array. | 12-05-2013 |
20140072313 | OPTICAL TRANSMISSION APPARATUS - A first clock modulator branches a light beam, varies a phase difference of the resulting light beams according to a first clock, and causes interference of the light beams. A second clock modulator branches a light beam from the first clock modulator and synchronized with the first clock, varies a phase difference of the resulting light beams according to a second clock, and causes interference of the light beams. A third clock modulator branches a light beam from the first clock modulator and inversely synchronized with the first clock, varies a phase difference of the resulting light beams according to a third clock, and causes interference of the light beams. The second clock and the first clock have identical cycles and differing phases. The third clock and the second clock have phases that differ by a 1/2 cycle. Four data modulators modulate the light beams from the clock modulators. | 03-13-2014 |
20140105615 | METHOD AND APPARATUS FOR GENERATION OF COHERENT AND FREQUENCY-LOCK OPTICAL SUBCARRIERS - A method and apparatus for generating sub-carriers is disclosed. Coherent optical sub-carriers with sub-carrier spacing are generated for carrying an orthogonal frequency division multiplexed (OFDM) signal. Multiple peaks are generated by cascading multiple phase modulators driven by different radio frequency sources. | 04-17-2014 |
20140119745 | OPTICAL MODULATING APPARATUS AND OPTICAL TRANSMITTER - An optical modulating apparatus includes driver that is mounted on a printed circuit board such that a signal electrode pad and a ground electrode pad of the driver are exposed in an opening of the printed circuit board. An optical modulating device is mounted on the printed circuit board, opposing the driver across the opening. A flexible circuit board is disposed in the opening. An end of a signal terminal of the flexible circuit board is electrically connected to a signal electrode of the optical modulating device. An end of a ground terminal of the flexible circuit board is electrically connected to a ground electrode of the optical modulating device. The other end of the signal terminal is soldered to the signal electrode pad of the driver, and the other end of the ground terminal is soldered to the ground electrode pad of the driver. | 05-01-2014 |
20140193163 | SIGNAL PROCESSING DEVICE, SIGNAL PROCESSING METHOD, AND COMMUNICATION DEVICE - A signal processing device includes: a plurality of multipliers configured to obtain a first multiplication result by multiplying a tap coefficient by 1/√2; a plurality of mappers configured to output a mapping result based on a first mapping coefficient and a digital input signal; and a plurality of first selectors configured to select the first multiplication result based on the mapping result. | 07-10-2014 |
20140205302 | PHOTON PHASE MODULATING SYSTEM - The present invention utilizes a high-speed serial data transceiver to generate two high-speed electric pulse signals. After passing through a gain network, the signals are used for driving an electro-optic phase modulator (PM) so as to realize phase modulation of photon signals. The present invention may directly use a high-speed digital signal to realize a four-phase modulation function needed by the BB84 quantum key distribution protocol without using a digital to analog converter or an analog switch. This can prevent modulation rate from being restricted by links including digital-to-analogue conversion, switching of the analogue and the like. A dual-electrode electro-optic phase modulator scheme can also effectively reduce requirements for amplitude of a modulation driving signal, thus facilitating realization of high-speed phase modulation, which meets requirements of quantum key distribution. | 07-24-2014 |
20140233965 | System and Method for Monitoring and Control of an Optical Modulator for an M-QAM Transmitter - A system includes an optical power meter operable to generate an optical power signal corresponding to the optical power of a received output signal generated by an optical IQ-modulator. The system further includes a processor operable to receive the optical power signal and determine, based on a minimization algorithm and the received optical power signal, a first bias voltage to be applied to a first sub-modulator of the optical IQ-modulator and a second bias voltage to be applied to a second sub-modulator of the optical IQ-modulator. The system may also include a peak power meter operable to generate a peak power signal corresponding to the peak power of the received output signal generated by the optical IQ-modulator, wherein the processor is further operable to determine, based on a minimization algorithm and the received peak power signal, a third bias voltage to be applied to a phase shift component of the optical IQ-modulator. | 08-21-2014 |
20140294401 | OPTICAL TRANSMITTER AND METHOD THEREOF - An optical transmitter including an optical modulator comprising a first modulator and a second modulator connected in parallel to each other in the form of a Mach-Zehnder interferometer, and a phase shifter connected to the second modulator in series, a high-speed generator configured to generate a single carrier signal or multi-carrier signals and apply the generated single carrier signal or multi-carrier signals to the optical modulator, and an output stabilizer configured to stabilize a final output optical signal of the optical modulator by controlling a bias of each of the first modulator, the second modulator and the phase shifter. | 10-02-2014 |
20140294402 | OPTICAL TRANSMISSION APPARATUS, OPTICAL TRANSMISSION METHOD AND PROGRAM FOR OPTICAL TRANSMISSION - An object of the invention is to provide an optical transmission apparatus capable of reducing the influence of nonlinear effect of an optical fiber, suppressing a band requested to a device from being widened, easily bias controlling a modulator, and flexibly switching plural modulation methods. | 10-02-2014 |
20140328601 | OPTICAL MODULATOR AND METHOD OF ENCODING COMMUNICATIONS TRAFFIC IN A MULTILEVEL MODULATION FORMAT - An optical modulator is described, comprising—an optical splitter to receive an optical carrier signal and split it into sub-signals; modulation assemblies, each comprising a binary optical modulator to apply a binary phase shift keyed, (BPSK) modulation to a respective optical sub-signal to form a BPSK modulated optical sub-signal. Modulation assemblies comprise a phase-shifter, each to apply a phase shift to the respective BPSK modulated optical sub-signal in dependence on a pre-selected modulation format; an encoding apparatus to receive communications traffic, to map into symbols, and to generate and transmit a respective drive signal to the optical modulator of a modulation assembly, each drive signal to cause the optical modulator to apply said BPSK modulation, to encode the symbols onto the respective optical carrier sub-signal; and a combiner to receive each BPSK modulated optical sub-signal to form an output optical signal having said multilevel modulation format. | 11-06-2014 |
20140376925 | Method and System for Modulating Optical Signals as High-Dimensional Lattice Constellation Points to Increase Tolerance to Noise - A method modulates data for optical communication by first encoding the data using a forward error correction (FEC) encoder to produce encoded data, which are encoded using a block encoder to produce block encoded data such that Hamming distances between code words that represent the block encoded data are increased. The block encoded data are mapped to produce mapped data such that Euclidian distances between the constellation points are increased. Then, the mapped data are modulated in a transmitter to a modulated signal for an optical channel. | 12-25-2014 |
20150063827 | METHOD FOR MODULATING A CARRIER LIGHT WAVE - Method for modulating a carrier light wave to achieve, a modulated light wave which carries information by symbols selected from a set of at least two different symbols. The light led through each path is phase-shifted by a respective total variable part phase shift, which for each path is the sum of at least three respective variable part phase shifts. Each variable part phase shift for each modulation state assumes one of two respective predetermined values, and each symbol is modulated using a respective combination of two such total variable part phase shifts. The modulation performed by the two paths is a PSK (Phase Shift Keying) modulation scheme, the group of symbols includes 2 | 03-05-2015 |
20150086217 | N2 TIMES PULSE ENERGY ENHANCEMENT USING COHERENT ADDITION OF N ORTHOGONALLY PHASE MODULATED PERIODIC SIGNALS - A method for increasing energy in a pulse optical beam is provided. The method may include: receiving an optical input beam having a period pulse train with a given repetition frequency; splitting the input beam into N optical signals; phase modulating each signal in the N optical signals at a different phase, such that the N optical signal are orthogonal to each other; and coherently combining each of the phase modulated signals into a single optical output beam. | 03-26-2015 |
20150093120 | CARRIER-SUPPRESSED LIGHT-GENERATING DEVICE - It is possible to suppress carrier light with a simple configuration when modulating the carrier light to generate optical sideband components. An optical carrier-suppressed signal generator includes first splitting means used to split input carrier light into two light beams, an optical modulator which modulates one split carrier light beam and outputs light including optical sideband components, a phase modulator which phase-modulates another split carrier light beam, and second or third splitting means used to split the output light of the optical modulator into two light beams. The output light split by the second or third splitting means and the output light of the phase modulator are multiplexed to obtain the amplitude of the signal waveform of optical power, and the optical modulator is controlled such that the obtained value is minimized. | 04-02-2015 |
20150093121 | OPTICAL SEMICONDUCTOR DEVICE, OPTICAL SEMICONDUCTOR DEVICE ARRAY, AND OPTICAL TRANSMITTER MODULE - An optical semiconductor device includes: an active region which includes an active layer which produces light when current is injected therein, a first diffraction grating layer having a first diffraction grating with a prescribed grating period, and a phase shift portion formed within the first diffraction grating layer, wherein the phase shift portion provides a phase shift not smaller than 1.5π but not larger than 1.83π; and a distributed reflection mirror region which is optically coupled to a first end of the active region as viewed along a direction of an optical axis, and which includes a second diffraction grating which reflects the light produced by the active region back into the active region. | 04-02-2015 |
20150104194 | PHASE SHIFT KEYING OPTICAL MODULATION APPARATUS AND METHOD OF ENCODING A SYMBOL ONTO AN OPTICAL CARRIER SIGNAL - Phase shift keying optical modulation apparatus comprising optical phase shifting apparatus and an optical modulator. The optical phase shifting apparatus is arranged to receive an optical carrier signal and is arranged to selectively apply a preselected optical phase shift to the optical carrier signal in dependence on a symbol of a 2N-level phase shift keying modulation format to be encoded onto the optical signal. The optical modulator is arranged to receive the optical carrier signal from the optical phase shifting apparatus and is arranged to apply a phase modulation to the optical carrier signal in dependence on the symbol, to thereby encode the symbol onto the optical carrier signal. The phase modulation is a phase-modulation of an N-level phase shift keying modulation format. | 04-16-2015 |
20150104195 | WORKING POINT CONTROLLING DEVICE AND METHOD FOR APPLYING MZ MODULATOR - Provided is a working point controlling device and method for applying MZ modulator, which includes: a light modulator; a transimpedance amplifier, transmits current outputted by PD of the modulator into voltage signal; a low-noise amplifier, detects low-frequency signal and amplifies the signal, in order to improve the signal/noise ratio; a high Q band-pass filter, detects error signal and amplifies the signal, in order to improve the signal/noise ratio; a first power level conditioning, performs power level condition on error signal of phase, in order that signal output meets A/D input rang; a micro processor, generates low-frequency signal and finishes software synchronization detection wave and ratio integration PI adjusting algorithm; a second power level conditioning, finishes D/A output voltage condition, in order that D/A output is able to meet direct current offset whole controlling range power voltage range of the light modulator. Applying present invention, the problems, that the hardware controlling circuit of current MZ modulator offset point is complex and controlling accuracy is not high, can be resolved. | 04-16-2015 |
20150132014 | QPSK SIGNAL CONJUGATE RELATIONSHIP IDENTIFICATION METHOD AND APPARATUS, AND DISPERSION COMPENSATION METHOD AND SYSTEM - The present invention discloses a QPSK signal conjugate relationship identification method and apparatus. The method includes: receiving a first binary sequence signal, using the first binary sequence signal to modulate an optical signal, and determining, within a first predetermined range, a first bias voltage in a QPSK modulator; receiving a second binary sequence signal, using the second binary sequence signal to modulate the optical signal, determining a second range within the first predetermined range according to the first bias voltage, and determining, within the second range, a second bias voltage in the QPSK modulator; and determining a conjugate relationship of the QPSK signal according to a value relationship between the first bias voltage and the second bias voltage. The present invention features low costs and a small component size. | 05-14-2015 |
20150304051 | OPTICAL DEVICE - An optical device, comprising an optical component, configured to produce optical amplification; a component configured to intermittently supply coherent light to said optical component; and a controller, configured to apply a time varying signal to said optical component such that a plurality of light pulses are emitted during each period of time that said coherent light is received, wherein the plurality of light pulses emitted during each period have a fixed phase relation. | 10-22-2015 |
20150331262 | OPTICAL MODULATOR, OPTICAL TRANSMITTER, OPTICAL TRANSMISSION/RECEPTION SYSTEM, AND CONTROL METHOD FOR OPTICAL MODULATOR - An optical modulation unit outputs an optical signal generated by binary-modulating an input light. Phase modulation areas are formed on an optical wave guide. A drive circuit includes a plurality of drivers outputting drive signals according to an input digital signal to the phase modulation areas. A determination circuit determines the driver to be activated among the plurality of the drivers based on information expressing a transmission rate. A driver control circuit activates the driver specified by a result of a determination of the determination circuit and cuts off power supply to the driver other than the activated driver. A switching circuit switches connections between the plurality of the drivers and the phase modulation areas. A switching control circuit that controls the switching circuit to cause the drive signals to be applied from the activated driver to the phase modulation areas. | 11-19-2015 |
20150372755 | OPTICAL TRANSMITTING AND RECEIVING APPARATUS AND METHOD THEREOF BASED ON MULTICARRIER DIFFERENTIAL PHASE SHIFT KEYING - An optical transmitting apparatus based on multicarrier differential phase shift keying. The optical transmitting may include a multicarrier generator to output two or more optical signals, each of which has a different wavelength; two or more optical modulators to receive the two or more optical signals, respectively, which have been output from the multicarrier generator, wherein each of the two or more optical modulators modulates phases of the two or more received optical signals by electrical signals that are applied in pairs. | 12-24-2015 |
20150372768 | QUANTUM COMMUNICATION SYSTEM - A transmitter for a quantum communication system, the transmitter comprising an interferometer, the interferometer having a first path with a phase modulator and a second path configured such that light pulses entering the interferometer follow either the first path or the second path, the output of the first and second paths being combined, the transmitter further comprising an optical filter positioned such that photons exiting the interferometer pass through the optical filter, the optical filter being configured to restrict the frequency range of pulses passing through the optical filter and temporally broaden the pulses. | 12-24-2015 |
20150381283 | Method And System For A Silicon-Based Optical Phase Modulator With High Modal Overlap - Methods and systems for a silicon-based optical phase modulator with high modal overlap are disclosed and may include, in an optical modulator having a rib waveguide in which a cross-shaped depletion region separates four alternately doped sections: receiving an optical signal at one end of the optical modulator, modulating the received optical signal by applying a modulating voltage, and communicating a modulated optical signal out of an opposite end of the modulator. The modulator may be in a silicon photonically-enabled integrated circuit which may be in a complementary-metal oxide semiconductor (CMOS) die. An optical mode may be centered on the cross-shaped depletion region. The four alternately doped sections may include: a shallow depth p-region, a shallow depth n-region, a deep p-region, and a deep n-region. The shallow depth p-region may be electrically coupled to the deep p-region periodically along the length of the modulator. | 12-31-2015 |
20160011486 | OPTICAL MODULE AND TRANSMITTING APPARATUS | 01-14-2016 |
20160011488 | OPTICAL MODULE AND TRANSMITTING APPARATUS | 01-14-2016 |
20160080091 | HIGH DATA RATE OPTICAL TRANSPORT NETWORK USING 8-PSK - Methods, systems, and devices are described for modulating data for optical transmissions and demodulating data from optical transmissions. During modulation, bits are mapped to symbols using an 8-ary modulation scheme. The modulation scheme may be based on 8 Phase Shift Keying (8-PSK), Dual Polarization 8-PSK, or 7-1 PSK for which one of the symbols is located at or near the origin of the constellation. Streams with the symbol-mapped bits are modulated onto a waveform in the digital domain that is converted into a waveform in the analog domain before is output for conversion to an optical signal. The streams may be filtered at baseband with at least one discrete pulse-shaping filter. During demodulation, pulse-shaped data received from an optical signal and comprising symbol-mapped bits based on the 8-ary modulation scheme is sampled. The sampled data is filtered with at least one discrete pulse-shaping filter, and then equalized and demodulated. | 03-17-2016 |
20160099781 | MEMORY CONTROLLER, MEMORY SYSTEM INCLUDING THE SAME, AND ELECTRONIC DEVICE INCLUDING THE MEMORY SYSTEM - A memory system in accordance with an embodiment of the inventive concept includes a memory controller comprising a controller optical transmission unit photoelectrically-converting a data signal to output a first optical modulation signal and a second optical modulation signal, a first memory device which is optically connected with the memory controller to receive the first optical modulation signal, and a second memory device which is optically connected with the memory controller to receive the second optical modulation signal. The first optical modulation signal and the second optical modulation signal are complementary to each other. | 04-07-2016 |
20160134377 | Method and Apparatus for Transmitting Phase Shift Keyed Optical Signals - A burst-mode phase shift keying (PSK) communications apparatus according to an embodiment of the present invention enables practical, power-efficient, multi-rate communications between an optical transmitter and receiver. Embodiments may operate on differential PSK (DPSK) signals. An embodiment of the apparatus includes an average power limited optical transmitter that transmits at a selectable data rate with data transmitted in bursts, the data rate being a function of a burst-on duty cycle. 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. | 05-12-2016 |