Class / Patent application number | Description | Number of patent applications / Date published |
398029000 | Dispersion | 47 |
20080212962 | CHIRP MEASUREMENT METHOD, CHIRP MEASUREMENT APPARATUS AND THEIR APPLICATION - A chirp measurement apparatus includes a splitting section for splitting input signal light to two paths; a first dispersion medium with a total dispersion amount of +D (≠0) at a used wavelength, and a second dispersion medium with a total dispersion amount of −D (≠0) at the used wavelength; | 09-04-2008 |
20090214202 | Selecting Wavelengths And Routes In An Optical Network - Selecting a wavelength and a route includes facilitating communication through routes among nodes. Each route is associated with a plurality of wavelengths and comprises one or more segments that couple one node to another node. A polarization mode dispersion value is determined for each wavelength of each route to yield polarization mode dispersion values for each route. A wavelength and a route are selected according to the polarization mode dispersion values. | 08-27-2009 |
20090245787 | CHARACTERIZATION AND CONTROL OF OPTICAL DISPERSION COMPENSATING ELEMENT - An apparatus and method are applied to characterizing an dispersion-affecting element for use in controlling chromatic dispersion in an optical communications link. Information regarding the behavior of the dispersion-affecting element is recorded and stored in a medium that is provided for deployment with the dispersion-affecting element to enable improved management and active control of the dispersion-affecting element. The suitability of the dispersion-affecting element for operating under different conditions may also be characterized. | 10-01-2009 |
20090317078 | OPTICAL TRANSMISSION DEVICE AND OPTICAL TRANSMISSION METHOD - The signal quality of ultra high-speed signals such as 40 Gbit/s and 100 Gbit/s are significantly degraded due to wavelength dispersion and nonlinear effects in an optical fiber. Thus, there is provided a transponder unit in which a light source is polarization multiplexed in a direction mutually orthogonal to a signal direction, in order to reduce the nonlinear effects in the optical fiber and improve the signal quality. At the same time, it is possible to monitor an amount of the wavelength dispersion in the optical fiber, allowing for more precise dispersion compensation design. | 12-24-2009 |
20090317079 | DISPERSION DETERMINING APPARATUS AND AUTOMATIC DISPERSION COMPENSATING SYSTEM USING THE SAME - A dispersion determining apparatus comprises a received waveform monitoring part ( | 12-24-2009 |
20100142946 | CHROMATIC DISPERSION MONITOR AND METHOD, CHROMATIC DISPERSION COMPENSATOR - The present invention relates to chromatic dispersion monitor and method, chromatic dispersion compensator. The chromatic dispersion monitor is used for estimating a chromatic dispersion in accordance with a chromatic dispersion correlation amount sequence, comprising: a phase differential unit, for obtaining a phase difference sequence by performing a phase differential calculation in accordance with the chromatic dispersion correlation amount sequence; a phase difference differential unit, for obtaining a phase difference differential sequence by performing a phase difference differential operation; and a chromatic dispersion estimating unit, for estimating the chromatic dispersion in accordance with the phase difference differential sequence obtained by the phase difference differential unit. | 06-10-2010 |
20100209101 | APPARATUS AND METHOD FOR MEASURING CHROMATIC DISPERSION - The chromatic dispersion of an optical component is measured with high accuracy using a simple set-up, which includes a pump light source, a probe light source, and a measuring means. Pump light having a wavelength λ | 08-19-2010 |
20100247095 | WAVELENGTH DIVISION MULTIPLEXING APPARATUS AND DISPERSION COMPENSATING METHOD FOR OPTICAL SIGNAL - When line trouble occurs in an optical network, the restoration time can be reduced. A transponder | 09-30-2010 |
20110019995 | OPTICAL TRANSMISSION RECEIVER AND METHOD FOR THE SAME - There is provided an optical transmission receiver includes an optical switch configured to switch between optical transmission channels, the optical transmission channels being gradually switched from one to the other, an optical amplifier configured to amplify a light propagating in the other of the optical transmission channels which is in a state subsequent to switching, and a switching speed controller configured to control a switching speed of the optical switch based on a level of the light amplified by the optical amplifier. | 01-27-2011 |
20110123191 | DISPERSION COMPENSATION DEVICE, OPTICAL RECEPTION DEVICE, METHOD FOR DISPERSION COMPENSATION, AND METHOD FOR OPTICAL RECEPTION - A dispersion compensation device includes: an optical branching unit to branch an optical signal to be received; a first dispersion compensator to perform dispersion compensation on one part of the optical signal branched by the optical branching unit with a variable compensation amount; a second dispersion compensator to perform dispersion compensation on another part of the optical signal branched by the optical branching unit; a monitoring unit to monitor the communication quality of an output optical signal of the second dispersion compensator; and a controlling unit to determine the direction of variation in chromatic dispersion of the optical signal based on the direction of variation in communication quality monitored by the monitoring unit and control the compensation amount of the first dispersion compensator based on the result of the determination. | 05-26-2011 |
20110129215 | Method and Apparatus for Broadband Mitigation of Polarization Mode Dispersion - Described is a method and system for reducing system penalty from polarization mode dispersion. The method includes receiving a plurality of signals at a receiving end of a transmission line, each signal being received on one of a plurality of channels of the transmission line and measuring a signal degradation of at least one of the channels of the transmission line. An amount of adjustment of a polarization controller is determined based on the signal degradation, the amount of adjustment being selected to reduce the polarization mode dispersion. The amount of adjustment is then transmitted to the polarization controller. | 06-02-2011 |
20110206371 | APPARATUS FOR SUPPORTING DESIGNING OF OPTICAL NETWORK, PROCESS FOR DESIGNING OPTICAL NETWORK, AND COMPUTER-READABLE, NON-TRANSITORY MEDIUM STORING NETWORK DESIGN PROGRAM - In an apparatus for supporting designing of an optical network including a plurality of nodes and links which connect the plurality of nodes: a storage stores information indicating distances of the links and information indicating amounts of chromatic dispersion in the links; and a path selection unit selects a path for use in transmission of an optical signal, from among a plurality of paths each extending from a start node to a destination node, by reference to the storage. The path selection unit selects the path for use in transmission on the basis of deviations of amounts of chromatic dispersion accumulated by transmission to respective nodes on each of the plurality of paths, from reference amounts at the respective nodes, and the reference amounts at the respective nodes on each of the plurality of paths are determined according to distances from the start node to the respective nodes. | 08-25-2011 |
20110229128 | OPTICAL NODE, OPTICAL NETWORK SYSTEM, AND METHOD FOR MEASURING POLARIZATION MODE DISPERSION - An optical node disposed along a transmission line that uses optical fiber. The optical node includes a first signal generator and a monitor. The first signal generator generates a first measurement signal for measuring polarization mode dispersion values and transmits the first measurement signal along the transmission line. The monitor detects a second measurement signal from the transmission line and measures polarization mode dispersion values by performing signal processing with respect to the second measurement signal. | 09-22-2011 |
20110280570 | COMPENSATING FOR END-TO-END GROUP DELAY RIPPLES - A device may include a group delay monitor and a signal receiver. The group delay monitor may be configured to obtain group delay data corresponding to group delay of an optical signal and provide the group delay data to a signal receiver. The signal receiver configured to obtain a time-domain digital signal corresponding to the optical signal, convert the time-domain digital signal into a frequency-domain signal, apply a digital filter constructed based on the group delay data to the frequency-domain signal to obtain an output signal, and transmit the output signal. | 11-17-2011 |
20120027406 | METHOD AND DEVICE FOR DETECTING DISPERSION, OPTICAL SIGNAL TRANSMISSION SYSTEM - The present invention discloses a method for detecting dispersion, overcoming disadvantages of complex configuration and insensitivity to a tiny dispersion of the method and device for detecting dispersion in the prior art. The inventive method includes: obtaining a signal within a predetermined bandwidth range from an optical signal received; obtaining an operated value of power via an operation on the signal within the predetermined bandwidth range; and obtaining amount of system dispersion according to a corresponding relation between the operated value of power and the amount of system dispersion. A device for detecting dispersion is disclosed, including a photoelectric filter operational unit and a processing unit, where an output of the photoelectric filter operational unit is connected to an input of the processing unit. The device for detecting dispersion of the present invention is applicable to an adaptive dispersion compensation system. An optical signal transmission system is further disclosed. | 02-02-2012 |
20120076493 | METHOD AND APPARATUS FOR COMPENSATING POLARIZATION MODE DISPERSION - Embodiments of the present invention provide a method and an apparatus for compensating polarization mode dispersion. The method mainly includes: extracting an SOP (state of polarization) and a PMD (polarization mode dispersion) value of an optical signal, generating an SOP control signal according to the SOP, and adjusting the SOP of the optical signal through the SOP control signal; and generating a PMD control signal according to the PMD value, and through the PMD control signal, compensating a PMD of the optical signal whose SOP is adjusted. Through the embodiments of the present invention, a rapid change of the SOP can be adaptively tracked, a poor PMD compensation effect caused by a failure of a PMD compensation unit to track a change of the SOP is avoided, compensation performance of the PMD compensation unit is improved, and rapid PMD compensation may be achieved. | 03-29-2012 |
20120087654 | OPTICAL COMMUNICATION SYSTEM, OPTICAL RECEIVER OF SAME, AND OPTICAL COMMUNICATION METHOD OF SAME - In a polarization demultiplexing optical communication system ( | 04-12-2012 |
20120121254 | MULTI-STAGE POLARIZATION MODE DISPERSION COMPENSATION - A polarization mode dispersion compensator that includes two stages, one for reducing or eliminating first order polarization mode dispersion of an optical signal, and second stage for reducing or eliminating higher order polarization mode dispersion of the optical signal. In each stage, the polarization is adjusted so as to reduce polarization mode dispersion. Based on the power levels of various polarization states generated at the second polarization controller, the optical signal to noise ratio may be estimated. Furthermore, based on the amount of adjustment used to control the polarization controllers and the differential group delay, the polarization mode dispersion may be estimated. | 05-17-2012 |
20120148235 | CONTROL CIRCUIT, COMMUNICATION SYSTEM, AND CONTROL METHOD - A communication system includes a transmitter, a receiver device, and a control circuit. The transmitter transmits an optical signal. The receiver device receives the optical signal. The control circuit reduces a power consumption of the receiver device based on an accumulated chromatic dispersion of the received optical signal. The receiver device includes a receiver, an analog/digital converter, and a digital signal processor. The receiver extracts a signal indicating a complex amplitude of the optical signal. The analog/digital converter converts the signal indicating the complex amplitude into a digital signal. The digital signal processor digitally-processes the digital signal. | 06-14-2012 |
20120163807 | REPRESENTATION OF THE PHYSICAL DEGRADATIONS IN AN OPTICAL COMMUNICATION NETWORK - To produce a representation of the physical degradation in an optical communication network comprising transparent switching nodes ( | 06-28-2012 |
20120213512 | CHROMATIC DISPERSION ESTIMATOR AND METHOD FOR ESTIMATING A CHROMATIC DISPERSION - A chromatic dispersion estimator for estimating a chromatic dispersion in an input signal block comprises a transformer for transforming the input signal block into a transformed signal block in frequency domain, a chromatic dispersion compensator for compensating a certain chromatic dispersion in the transformed signal block to obtain a compensated transformed signal block, an inverse transformer for inversely transforming the compensated transformed signal block into time domain to obtain an output signal, an adaptive filter for filtering the output signal to obtain a filtered signal, and a determiner for determining upon the basis of the filtered signal whether the certain chromatic dispersion corresponds to the chromatic dispersion in the input signal block. | 08-23-2012 |
20120230680 | TRANSMISSION QUALITY DETERMINATION METHOD, TRANSMISSION PATH SELECTION METHOD AND NETWORK MANAGEMENT SYSTEM - There is provided a method of determining transmission quality of a path in an optical communication network system obtained by connecting a plurality of networks, the method including: acquiring a value representing transmission performance corresponding to a network condition of each of spans in the path in the optical communication network system; and determining the transmission quality of the path on the basis of the acquired value representing transmission performance corresponding to the network condition of each of spans. | 09-13-2012 |
20120237214 | DISPERSION COMPENSATION DESIGN METHOD AND DISPERSION COMPENSATION DESIGN SYSTEM - A dispersion compensation design system includes a segment dividing unit to divide an optical network into segments of a linear network or a ring network, a path classifying unit to classify one of paths of the optical network, as a specific type path, the one of the paths being incapable of transmitting an optical signal and contained in a longer path having a route longer than that of the one of the paths and capable of transmitting the optical signal, a segment reconfiguration unit to reconfigure the segments so as to maximize a number of the specific type paths, a dispersion compensation amount computing unit to compute a dispersion compensation amount in any of spans of the optical network so as to minimize the number of the specific type paths within the reconfigured segment, and an update unit to update the dispersion compensation amount with the computed dispersion compensation amount. | 09-20-2012 |
20120281981 | METHOD AND APPARATUS FOR DETECTING CHROMATIC DISPERSION, AND METHOD AND APPARATUS FOR COMPENSATING CHROMATIC DISPERSION - A method of monitoring chromatic dispersion when transmitting an optical signal includes: applying, to an optical signal in which the symbol rate is f, a dip in optical intensity for every n symbols by means of pseudo-RZ modulation where n is an integer equal to or greater than 2, and transmitting the optical signal to which dips have been applied to a transmission path; receiving the optical signal that is transmitted in by the transmission path and detecting the intensity of a frequency component of k*f/n from the received signal where k is an integer equal to or greater than 1; and based on the detected intensity, generating a monitor signal that represents the chromatic dispersion amount. | 11-08-2012 |
20120321298 | Systems and Methods for Polarization Mode Dispersion Mitigation - In one exemplary embodiment, a method comprises transmitting an optical signal via the optical line, measuring a relative change in spectral intensity of the optical signal near a clock frequency (or half of that frequency) while varying a polarization of the optical signal between a first state of polarization and a second state of polarization, and using the relative change in spectral intensity of the optical signal to determine and correct the DGD of the optical line. Another method comprises splitting an optical signal traveling through the optical line into a first and second portions having a first and second principal states of polarization of the optical line, converting the first and second portions into a first and second electrical signals, delaying the second electrical signal to create a delayed electrical signal that compensates for a DGD of the optical line, and combining the delayed electrical signal with the first electrical signal to produce a fixed output electrical signal. | 12-20-2012 |
20130034352 | COHERENT RECEIVER APPARATUS AND CHROMATIC DISPERSION COMPENSATION METHOD - The present disclosure relates to the field of communications, and in particular, to a coherent receiver apparatus and a chromatic dispersion compensation method. The apparatus includes a polarization beam splitter and a chromatic dispersion compensation module. An optical splitter is disposed in front of the polarization beam splitter, and a chromatic dispersion monitoring module is connected between the optical splitter and the chromatic dispersion compensation module. The optical splitter is configured to split a modulated optical signal received by the coherent receiver apparatus and then transmit the split modulated optical signal to the chromatic dispersion monitoring module and the polarization beam splitter. The chromatic dispersion monitoring module is configured to perform chromatic dispersion monitoring on the modulated optical signal to determine a chromatic dispersion range of the modulated optical signal, and enable the chromatic dispersion compensation module to perform chromatic dispersion compensation in the chromatic dispersion range. | 02-07-2013 |
20130058644 | Blind Equalization Algorithms for Adaptive Polarization Recovery and PMD Compensation - A device and method are disclosed for blind equalization of an optical signal to implement adaptive polarization recovery, Polarization Mode Dispersion (PMD) compensation, and residual Chromatic Dispersion (CD) compensation in a digital coherent optical communication system. | 03-07-2013 |
20130077963 | Method for the Compensation of Nonlinear Impairments in Dispersion-Managed Optical Fiber Links Using Phase Conjugation and Equivalent Optical Link - A method for nonlinearity compensation for an optical transmission link includes determining a dispersion effect of a transmission link; applying a phase conjugation to the transmission link, the phase conjugation responsive to an input wave over the transmission link and providing a conjugated version of the input wave; and configuring an optimum equivalent link responsive to the phase conjugation after the transmission link to compensate for a non-linear dispersion effect from said transmission link | 03-28-2013 |
20130156421 | DISPERSION MEASUREMENT SYSTEM AND METHOD IN AN OPTICAL COMMUNICATION NETWORK - The invention relates to a system and method of dispersion measurement in an optical fibre network. The invention provides means for transmitting from a transmitting node, using a single tunable laser transmitter, two consecutive bursts of data at different wavelengths λ | 06-20-2013 |
20130170831 | PHASE-MODULATED TRANSMISSION CONTROL USING EMBEDDED CONTROL SYMBOLS - A system receives a phase-modulated signal that carries client symbols and a sequence that includes first symbols on which a first tone is to be based and having a first power level, and second symbols on which a second tone is to be based and having a second power level; processes the sequence to generate the first tone and the second tone; determines a power difference based on the first power level and the second power level; retrieves condition information that identifies a threshold for determining whether a condition is associated with the signal; determines whether the power difference is greater than the threshold; and outputs an instruction, to adjust a parameter, used to transmit the signal, based on the determination that the condition is associated with the signal, where adjusting the parameter causes the power difference to decrease to a level that is less than the threshold. | 07-04-2013 |
20130195445 | COMPENSATION OF MODAL DISPERSION OF POLARIZATION BY DETERMINISTIC JAMMING OF POLARIZATION - A method of calculating a series of control parameters to be applied to a polarization controller arranged so as to compensate for the modal dispersion of polarization affecting an optical signal passing through an optical link by calculating a plurality of polarization states of which the respective representations on a Poincaré sphere are separated from one another by a distance greater than a minimum distance dependent on an acceptable threshold of bit error ratios and, for each state of polarization thus calculated, associating at least one control parameter to be applied to the polarization controller with the calculated state of polarization. | 08-01-2013 |
20130266311 | METHOD AND APPARATUS FOR ESTIMATING CROSS-PHASE MODULATION IMPAIRMENTS - A system for estimating cross-phase modulation (XPM) impairments, wherein the method comprises: determining, according to a pump Jones matrix of a pump channel and a probe Jones matrix of a probe channel of each of fiber spans except for the first fiber span in a fiber transmission system, a polarization mode dispersion (PMD)-induced relative polarization status rotation matrix between channels of the each of fiber spans; and determining, according to the rotation matrix of the each of fiber spans, dispersion of a pump signal of the each of fiber spans, differential delay of the pump signal relative to a probe signal of the each of fiber spans and a gain of the each of fiber spans, polarization crosstalk and phase noise of the XPM impairments in the fiber transmission system. This allows the XPM impairments in the effect of the polarization mode dispersion to be quickly and accurately estimated, | 10-10-2013 |
20130343748 | APPARATUS AND METHOD FOR MONITORING OPTICAL SIGNAL TRANSMISSION IN OPTICAL FIBERS - An apparatus for monitoring optical signal transmission in a plurality of optical fibers may include a fixture for introducing a bend into the plurality of fibers arranged at respective predetermined locations on the fixture, to cause a portion of light propagating in any of the fibers to scatter out therefrom. The apparatus may include a lens unit positioned to focus the scattered light onto predetermined photo-detectors of an array, in accordance with the fiber from which the scattered light emanates, and generate image data indicating a characteristic of the scattered light detected at respective ones of the photo-detectors identified by location in the array corresponding to the respective ones of the photo-detectors. | 12-26-2013 |
20130343749 | WAVELENGTH DISPERSION AMOUNT ESTIMATION METHOD, WAVELENGTH DISPERSION COMPENSATION CIRCUIT, AND RECEPTION DEVICE - A wavelength dispersion amount estimation method, a wavelength dispersion compensation circuit, and a receiving device which rapidly estimate and set a wavelength dispersion amount to compensate with high accuracy at the receiving device which compensates waveform distortion at an optical fiber transmission path. The wavelength dispersion compensation circuit includes an analog-digital converter which converts an optical analog waveform received from the optical fiber transmission path to a digital signal, a digital signal processor which compensates waveform distortion of the digital signal output from the analog-digital converter due to wavelength dispersion at the optical fiber transmission path with a dispersion compensation amount estimated with the wavelength dispersion amount estimation method, and a symbol clock extractor which extracts a symbol arrival timing clock of received data contained in the digital signal output from the analog-digital converter and outputs strength of the symbol arrival timing clock as the clock detection value. | 12-26-2013 |
20140003807 | CROSSTALK MEASURING METHOD AND CROSSTALK MEASURING DEVICE | 01-02-2014 |
20140016929 | METHOD FOR ESTIMATING AMOUNT OF WAVELENGTH DISPERSION, WAVELENGTH DISPERSION COMPENSATION CIRCUIT, AND RECEIVING DEVICE - A wavelength dispersion amount estimation method, a wavelength dispersion compensation circuit, and a receiving device which rapidly estimate and set a wavelength dispersion amount to compensate with high accuracy at the receiving device which compensates waveform distortion at an optical fiber transmission path. A wavelength dispersion compensation circuit includes an analog-digital converter which converts an optical analog waveform received from the optical fiber transmission path to a digital signal, a digital signal processor which compensates waveform distortion of the digital signal output from the analog-digital converter due to wavelength dispersion at the optical fiber transmission path with a dispersion compensation amount estimated with the wavelength dispersion amount estimation method, and a symbol clock extractor which extracts a symbol arrival timing clock of received data contained in the digital signal output from the analog-digital converter and outputs strength of the symbol arrival timing clock as the clock detection value. | 01-16-2014 |
20140086577 | MULTIMODE OPTICAL FIBER SYSTEMS WITH ADJUSTABLE CHROMATIC MODAL DISPERSION COMPENSATION - Multimode optical fiber systems with adjustable chromatic modal dispersion compensation are disclosed, wherein the system includes a VCSEL light source and primary and secondary optically coupled multimode optical fibers. Because the VCSEL light source has a wavelength spectrum that radially varies, its use with the primary multimode optical fiber creates chromatic modal dispersion that reduces bandwidth. The compensating multimode optical fiber is designed to have a difference in alpha parameter relative to the primary multimode optical fiber of −0.1≦Δα≦−0.9. This serves to create a modal delay opposite to the chromatic modal dispersion. The compensation is achieved by using a select length of the compensating multimode optical fiber optically coupled to an output end of the primary multimode optical fiber. The compensating multimode optical fiber can be configured to be bend insensitive. | 03-27-2014 |
20140086578 | MULTIMODE OPTICAL FIBER SYSTEMS WITH ADJUSTABLE CHROMATIC MODAL DISPERSION COMPENSATION - Multimode optical fiber systems with adjustable chromatic modal dispersion compensation are disclosed, wherein the system includes a VCSEL light source and primary and secondary optically coupled multimode optical fibers. Because the VCSEL light source has a wavelength spectrum that radially varies, its use with the primary multimode optical fiber creates chromatic modal dispersion that reduces bandwidth. The compensating multimode optical fiber is designed to have a difference in alpha parameter relative to the primary multimode optical fiber of −0.1≦Δα≦−0.9. This serves to create a modal delay opposite to the chromatic modal dispersion. The compensation is achieved by using a select length of the compensating multimode optical fiber optically coupled to an output end of the primary multimode optical fiber. The compensating multimode optical fiber can be configured to be bend insensitive. | 03-27-2014 |
20140140693 | METHODS AND SYSTEMS FOR BULK DISPERSION MONITORING - A method and system for measuring chromatic dispersion, experienced by ASK/PSK modulated optical signals, are provided. Dispersion measurement is enabled either by encoding an additional overhead at lower baud rate or by monitoring signal SOP or RF spectrum of signal SOP. The bulk chromatic dispersion of the link is measured by analyzing the dispersion broadening of the overhead constellation or signal temporal diagram, or time-overlapped signal diagram, or overhead spectrum. This information is used to reduce the computation time required for electronic recovery of a highly dispersed signal. | 05-22-2014 |
20140153920 | DIGITAL DEMODULATOR ARCHITECTURE - Methods, systems, and devices are described for a digital demodulator device for processing received optical signals. The device may include a quadrature error filter that receives a digitized version of an optical signal, and removes quadrature errors to generate a filtered series of data samples. The device may also include a frequency offset removal module for performing frequency rotation on the filtered series of data samples. The device may include a chromatic dispersion compensation module which removes chromatic dispersion from horizontal and vertical polarization channels. The device may include a polarization mode dispersion (PMD)/polarization dependent loss (PDL) compensation module which compensates for interference caused by PMD and PDL. The device may also include a phase recovery module configured to track and correct phase. | 06-05-2014 |
20140348501 | EMBEDDED APPARATUS TO MONITOR SIMULATED BRILLOUIN SCATTERING FROM RAMAN AMPLIFIER IN FIBER OPTICS TRANSMISSION SYSTEM - The embedded apparatus disclosed herein may measure reflection coefficient values associated with back reflections in a fiber optics transmission system during a variable detection window to detect normal conditions, simulated Brillouin scattering (SBS), or excessive back reflections triggering remedial action. For example, the back reflections may indicate normal conditions if the reflection coefficients measured during an entire detection window remained below a threshold or a maximum reflection coefficient observed therein was below the threshold. Alternatively, the back reflections may trigger remedial action if the reflection coefficients measured in the entire detection window exceeded the threshold or a minimum reflection coefficient observed therein was above the threshold. Otherwise, the back reflections may indicate the SBS effect if the reflection coefficients measured during the detection window included points above and below the threshold or the minimum and maximum reflection coefficients observed therein were below and above the threshold. | 11-27-2014 |
20150010300 | APPARATUS AND METHOD FOR ESTIMATING INTRA-CHANNEL NONLINEAR DAMAGE - An apparatus and method for estimating intra-channel nonlinear damage, including: a first determining unit configured to determine a nonlinear phase shift weighting dispersion distribution function of an optical fiber transmission link according to a parameter of the optical fiber transmission link; a segmenting unit configured to segment the nonlinear phase shift weighting dispersion distribution function of the optical fiber transmission link into at least one rectangle; a calculating unit configured to respectively calculate a nonlinear perturbation coefficient of each rectangle in the at least one rectangle, and perform summation on the nonlinear perturbation coefficients of all the rectangles, so as to obtain a nonlinear perturbation coefficient of the optical fiber transmission link; and a second determining unit configured to determine intra-channel nonlinear damage of the optical fiber transmission link according to the nonlinear perturbation coefficient of the optical fiber transmission link. | 01-08-2015 |
20150295643 | ESTIMATION APPARATUS AND METHOD FOR NONLINEAR DISTORTION AND RECEIVER - Embodiments of the present disclosure provide an estimation apparatus and method for nonlinear distortion and a receiver. The estimation method for nonlinear distortion includes: sampling a band-limited analog signal to obtain a sampling sequence; calculating a nonlinear perturbation coefficient in nonlinear distortion estimation based on a Nyquist pulse; calculating a nonlinear perturbation term superimposed on a signal by using the nonlinear perturbation coefficient and the sampling sequence; and calculating a nonlinear distortion waveform by using the nonlinear perturbation term. With the embodiments of the present disclosure, not only any modulation formats are compatible, but also advantages of high precision and good adaptability may be achieved. | 10-15-2015 |
20150318920 | DISTRIBUTED ACOUSTIC SENSING USING LOW PULSE REPETITION RATES - A distributed acoustic sensing system and a method of obtaining acoustic levels using the distributed acoustic sensing system are described. The distributed acoustic sensing system includes an optical fiber, a light source to inject light into the optical fiber, and a photodetector to sample a DAS signal in each section of one or more sections of the optical fiber resulting from two or more points within the section on the optical fiber over a period of time. The system also includes a processor to process only a low frequency portion of the DAS signal to obtain the acoustic levels at each of the one or more sections on the optical fiber over the period of time, the low frequency portion of the DAS signal being less than 10 Hz. | 11-05-2015 |
20150372765 | SIGNAL PROCESSING DEVICE AND SIGNAL PROCESSING METHOD - A nonlinear compensation unit ( | 12-24-2015 |
20160191162 | DEVICE FOR CONTROLLING POLARIZATION OF OPTICAL FIBER AND METHOD OF CONTROLLING POLARIZATION OF OPTICAL FIBER USING SAME - A device for controlling polarization of an optical fiber and a method of controlling the polarization of an optical fiber using the same are disclosed herein. The device includes optical fiber supports, an optical fiber holder, and an optical fiber curvature changing unit. The optical fiber supports receive an optical fiber, and support both ends of the optical fiber. The optical fiber holder includes an optical fiber guide element that guides the optical fiber, drawn out of the optical fiber supports, through a path. The optical fiber curvature changing unit is located between the optical fiber and the optical fiber guide element, and changes the curvature of the optical fiber by exerting external force onto the optical fiber. | 06-30-2016 |
20160254861 | A Method of Characterizing a Multimode Optical Fiber Link and Corresponding Methods of Fabricating Multimode Optical Fiber Links and of Selecting Multimode Optical Fibers from a Batch of Multimode Optical Fibers | 09-01-2016 |