Class / Patent application number | Description | Number of patent applications / Date published |
398147000 | Dispersion compensation | 55 |
20080240727 | TUNABLE DISPERSION COMPENSATOR - The tunable dispersion compensator | 10-02-2008 |
20080279563 | Apparatus and Method for Self-Adaptive Dispersion Compensating - An apparatus for adaptive dispersion compensation and the method thereof applied to adaptive dispersion compensation in an optical communication system comprises: input optical fiber, an optical tunable dispersion compensator, output optical fiber, a signaling system unit, a control logic unit which is used to calculate the adjustment value of the optical tunable dispersion compensator according to the dispersion performance information detected by the signaling system unit, then control the optical tunable dispersion compensator through feedback, thus adjust the dispersion compensation value of the optical dispersion compensator. The present invention overcomes the deficiency of the prior art by adaptively compensating the system dispersion in real time, thus the transmission quality of the system signal is effectively guaranteed, and in the case that the dispersion of the lines or optical network nodes varies, it can implement the adaptive dispersion compensating for multi-channel or single-channel system. | 11-13-2008 |
20080310855 | Optical Transmission Equipment and Method for Controlling Thereof - The optical transmission equipment includes: a demultiplexer for demultiplexing a transmitted wavelength-multiplexed optical signal to first and second optical signals; a first variable dispersion compensation unit; a second variable dispersion compensation unit; a first error detector; a second error detector; and a dispersion compensation control unit for controlling dispersion compensation amounts of the first and second variable dispersion compensation units based on the detection result of the first or second error detector. Upon detection of a signal error in the first optical signal, the first variable dispersion compensation unit is controlled to change from a first compensation amount to a third compensation amount, and the second variable dispersion compensation unit is controlled to change from a second compensation amount to a fourth compensation amount. | 12-18-2008 |
20090016737 | ELECTRONIC DISPERSION COMPENSATION SYSTEMS AND METHODS - An electronic dispersion compensation module may perform one or more electronic dispersion compensation solutions. The electronic dispersion compensation module may include a solution control module. The solution control module may configure the electronic dispersion compensation module to perform an electronic dispersion compensation solution using data indicating a bit error rate. A bit error rate module may create the data indicating a bit error rate. The bit error rate module may form part of a clock and data recovery module. The electronic dispersion compensation module may be configured to receive a signal from a backplane and may also be configured to apply any of a plurality of electronic dispersion compensation solutions to the signal received from the backplane. | 01-15-2009 |
20090028576 | Frequency-Domain Equalization of the Fiber Optic Channel - Systems and methods for frequency-domain compensation in optical communication systems. In pre-equalization embodiments, the transmitter transforms the data stream into a frequency domain signal and applies a compensation filter before transforming it back into a pre-distorted time domain signal. As the pre-distorted time domain signal propagates through the optical channel, optical dispersion effects counter the pre-distortion, producing an equalized signal at the channel output. In post-equalization embodiments, the receiver transforms the received signal into a frequency domain signal and applies a compensation filter before transforming it back into an equalized time domain signal. Pre-equalization may prove less expensive due to the square-law characteristic of photodetectors employed by most receivers. | 01-29-2009 |
20090060523 | In-service optical dispersion determining system and method - A system and method for in-service optical dispersion determination are provided. Optical dispersion is determined by splitting a first optical signal into two components, introducing a time delay between the two components such that corresponding pulses of the two components partially overlap, combining the two components to generate a combined optical signal comprising a first component and a second component, determining power of the combined optical signal while applying a plurality of dispersion compensation values, in order to determine a dispersion compensation value that results in a minimum detected power of the combined optical signal. Polarization Mode Dispersion is determined by adjusting the time delay that is introduced until the power of the combined optical signal is substantially equal for all of the plurality of dispersion compensation values. | 03-05-2009 |
20090136239 | Optical Signal Transmission Control Apparatus and Optical Signal Transmission Control Method - An optical signal transmission control apparatus that controls transmission of optical signals transmitted via a plurality of redundant routes. The optical signal transmission control apparatus includes a delay difference adjusting unit that adjusts a transmission delay difference between the optical signals of each route by converting a wavelength of the optical signal and making the optical signal with a converted wavelength pass through a waveguide in which a transmission delay of the optical signal changes continuously depending on the wavelength, and a waveform degradation compensating unit that compensates degradation of a waveform of the optical signal, while maintaining the transmission delay difference adjusted by the delay difference adjusting unit. | 05-28-2009 |
20090142069 | Method and apparatus for repeaterless high-speed optical transmission over single-mode fiber using coherent receiver and electronic dispersion compensation - Repeaterless transmission of differential phase-shift keying (DPSK) at 10.7 Gb/s over at least 304 km of standard single-mode fiber is obtained through use of a coherent optical receiver including electronic dispersion compensation. High receiver sensitivity and high tolerance to nonlinearities of DPSK, allow overcoming a total link loss of 58 dB with a 3 dB system margin, through use in the receiver of heterodyne detection to preserve phase distortions resulting from chromatic dispersion, to permit electronic dispersion compensation to be used. | 06-04-2009 |
20090175629 | DISPERSION COMPENSATION METHOD AND FIBER TRANSMISSION SYSTEM - A dispersion compensation method and a fiber transmission system are disclosed, pertaining to the field of fiber communications. The dispersion compensation method includes: after performing electrical pre-compensation processing on a digital transmit signal, the transmitting end controls the electrical/optical converting module to output a distorted optical signal; after receiving the optical signal, the receiving end performs post-compensation processing after converting the optical signal into an electrical signal, or converts the optical signal into an electrical signal after performing post-compensation processing on the optical signal. The fiber transmission system includes: a pre-compensation signal processing module, an optical source, an electrical/optical converting module, a fiber transmission line, an optical/electrical converting module, and a post-compensation processing module. With the technical solution of the present disclosure, the non-linear effect may be suppressed, and a flexible dispersion compensation solution may be provided for a dynamically configurable network. | 07-09-2009 |
20090238578 | APPARATUS AND METHOD OF COMPENSATING FOR COMPACT DIGITAL DOMAIN CHROMATIC DISPERSION - A method and apparatus of compensating for compact digital domain chromatic dispersion. The distortion of an optical signal due to chromatic dispersion is compensated by a digital signal processing in the electrical domain, either prior to the optical transmitter or following the receiver. The circular coefficient approximation and sub-band processing reduce the amount of computations to execute a given level of chromatic dispersion compensation compared to a direct finite impulse response filter implementation. | 09-24-2009 |
20090269078 | Dispersion compensator and optical communication device having same - A dispersion compensator ( | 10-29-2009 |
20090285582 | POLARIZATION MODE DISPERSION COMPENSATION - An apparatus and method for correcting for the polarization mode distortion of an optical signal is described. The optical data signal to be transmitted is processed by a switch configured to place the signal into a plurality of polarization states on a periodic basis. At the receiving end of the system, a portion to the signal is coupled to a polarimeter and the wavelength-dependent state of polarization (SOP) of the received signal determined for the plurality of polarization states imposed on the transmitted signal. The data for two of the transmitted polarization states is selected to be used as the basis for correcting the SOP so as to compensate for the wavelength dependence thereof. The corrections may be applied in an optical pulse shaper. | 11-19-2009 |
20090304391 | OPTICAL COMMUNICATIONS SYSTEM HAVING CHROMATIC DISPERSION AND POLARIZATION MODE DISPERSION COMPENSATION - Described are an optical communications system and a method that allow for compensation of chromatic dispersion and polarization mode dispersion imparted to a communications signal propagating through an optical link. The system is based on a cost-effective optical transport architecture that accommodates baud rates exceeding 15 Gbaud and eliminates the need for costly optical dispersion compensators. Compensation for polarization mode dispersion is performed at the receiver using nonlinear processing. Advantageously, direct detection modulation using inexpensive electro-optic system components can be used in place of more costly and complex coherent and differential modulation formats. Digital filtering can be performed at the transmitter and the input signal can be inverted based on the nonlinearity of the transmitter electro-optic components. Consequently, the bandwidth and linearity requirements for the transmitter electro-optic components are relaxed, and cost reductions are realized. | 12-10-2009 |
20090310975 | ADAPTIVE DISPERSION COMPENSATION SYSTEM AND METHOD FOR OPTICAL COMMUNICATION NETWORK - The present invention discloses an adaptive dispersion compensation system and a method used in optical communication network, comprising at least one performance detecting unit ( | 12-17-2009 |
20100046957 | METHOD AND SYSTEM FOR A POLARIZATION MODE DISPERSION TOLERANT OPTICAL HOMODYNE DETECTION SYSTEM WITH OPTIMIZED TRANSMISSION MODULATION - An optical homodyne communication system and method in which a side carrier is transmitted along with data bands in an optical data signal, and upon reception, the side carrier is boosted, shifted to the center of the data bands, and its polarization state is matched to the polarization state of the respective data bands to compensate for polarization mode dispersion during transmission. By shifting a boosted side carrier to the center of the data bands, and by simultaneously compensating for the effects of polarization mode dispersion, the provided system and method simulate the advantages of homodyne reception using a local oscillator. The deleterious effects of chromatic dispersion on the data signals within the data bands are also compensated for by applying a corrective function to the data signals which precisely counteracts the effects of chromatic dispersion. | 02-25-2010 |
20100061737 | OPTICAL RECEIVER WITH LOW-PASS FILTER AND MLSE UNIT, AND OPTICAL COMMUNICATION SYSTEM IMPLEMENTING THE OPTICAL RECEIVER - An optical receiver is disclosed in which the error rate for the received data may be effectively reduced even for the non-linear optical transmission system that provides a directly modulate laser diode as the optical transmitter and the single mode fiber inevitably accompanying with the dispersion as the transmission medium. The optical receiver includes a photodiode (PD), a low-pass filter (LPF) and a maximum likelihood sequence estimator (MLSE) carrying out the Viterbi algorithm. The LPF in front of the MLSE effectively suppresses the ringing appeared in the received signal to generate a replica data with good reproducibility. | 03-11-2010 |
20100119237 | DYNAMIC TUNABLE LOW LATENCY CHROMATIC DISPERSION COMPENSATOR - A dynamic tunable chromatic dispersion compensator with low latency is provided that includes a chirped fiber Bragg grating in a compensating optical fiber core. The chirped fiber Bragg grating includes wavelength gratings spaced at distances varying with respect to the length of the compensating optical fiber core to compensate for differential delay in a synchronous time protocol for a bidirectional computer data communication link. The dynamic tunable chromatic dispersion compensator also includes one or more controllable elements to modify the length of the compensating optical fiber core in response to one or more commands, and an optical junction to optically couple the chirped fiber Bragg grating to an optical fiber of the bidirectional computer data communication link. | 05-13-2010 |
20100209115 | Frequency-Domain Equalization of the Fiber Optic Channel - Systems and methods for frequency-domain compensation in optical communication systems. In pre-equalization embodiments, the transmitter transforms the data stream into a frequency domain signal and applies a compensation filter before transforming it back into a pre-distorted time domain signal. As the pre-distorted time domain signal propagates through the optical channel, optical dispersion effects counter the pre-distortion, producing an equalized signal at the channel output. In post-equalization embodiments, the receiver transforms the received signal into a frequency domain signal and applies a compensation filter before transforming it back into an equalized time domain signal. Pre-equalization may prove less expensive due to the square-law characteristic of photodetectors employed by most receivers. | 08-19-2010 |
20100215377 | OPTICAL NETWORK DESIGN APPARATUS AND DISPERSION COMPENSATION DESIGN METHOD - In an optical network design apparatus, a constraint setter sets a first constraint that one of alternative values given beforehand is selected as the dispersion compensation amount of each node, sets a first margin value that assumes a nonnegative value, sets a second constraint that the first margin value is equal to or greater than the difference between the residual dispersion and the lower bound of an allowable range, sets a second margin value that assumes a nonnegative value, and sets a third constraint that the second margin value is equal to or greater than the difference between the upper bound of the allowable range and the residual dispersion. A calculation controller generates an objective function including the first, second and third constraints and including a summation of the first and second margin values for all paths, and derives a solution that minimizes the objective function. | 08-26-2010 |
20100266289 | Even-Order Harmonic Cancellation and Increased RF Gain Using Dual-Output Mach-Zehnder Modulator with Two Wavelength Input - A method and system for processing analog optical signals to produce a single RF output free from even-order harmonic distortion. Two analog optical signals of different wavelengths λ | 10-21-2010 |
20100296818 | COST EFFECTIVE OPTICAL TRANSMISSION WITH FAST RAMAN TILT TRANSIENT CONTROL - A method for cost-effective optical transmission with fast Raman tilt or other transient event control uses a combination of Erbium-doped fiber amplifiers (EDFAs) and Raman fiber amplifiers (RFAs), where EDFAs are used as the primary optical amplifiers to compensate the span loss while the RFA (advantageously a forward-pumped RFA) is used only in some specific spans with a feed-forward control circuit serving as a fast Raman tilt transient compensator, the RFA also serving as an optical amplifier. A long haul optical transmission system using feed-forward controlled RFA's periodically spaced along its length, for example, when add-drop multiplexing is used, makes full use of the economics of EDFAs and the fast tilt transient control capability of a RFA enabled by an adjustable speed feed-forward or feed-back control technique. | 11-25-2010 |
20100329693 | MULTI DIMENSION HIGH SECURITY COMMUNICATION OVER MULTI MODE FIBER WAVEGUIDE - A system may comprise a single wavelength laser; a modulator optically coupled to said laser; a length of multi-mode fiber optically coupled to said modulator; and a phase mask optically coupled to said fiber. The phase mask may be configured to filter out modes other than a selected mode. | 12-30-2010 |
20110058820 | Optical transmission system, optical transmission equipment, and chromatic dispersion compensation method - An optical transmission system includes an optical transmission equipment and an optical receiving device. The optical transmission equipment transmits an optical signal from a first adjacent node to a second adjacent node, and includes an optical multiplexing and demultiplexing unit that demultiplexes the optical signal from the first adjacent node into an optical transmission signal to be transmitted to the second adjacent node and an optical demultiplexed signal, and a compensating unit that partially compensates chromatic dispersion in the optical demultiplexed signal. The optical receiving device receives the optical signal from the optical transmission equipment, and includes a converting unit that converts the optical demultiplexed signal the chromatic dispersion of which is partially compensated by the compensating unit into an electric digital signal, and a digital processing unit that compensates chromatic dispersion remaining in the electric digital signal. | 03-10-2011 |
20110176813 | Method and System for Electrical Domain Optical Spectrum Shaping - A system is provided for electrical domain optical spectrum shaping. The system may include a laser, a modulator, a first electrical filter, and a second electrical filter. The laser may be configured to output an optical carrier signal. The modulator may be configured to modulate the optical carrier signal to output a modulated optical signal based on a first filtered input signal and a second filtered input signal received by the modulator. The first electrical filter may be configured to filter a first input signal to produce the first filtered input signal. The second electrical filter may be configured to filter a second input signal to produce the second filtered input signal. | 07-21-2011 |
20110236032 | Low Nonlinearity Long Haul Optical Transmission System - A long haul optical fiber transmission system includes a transmitter, a receiver optically coupled to the transmitter with at least two composite optical fiber spans, at least one amplifier between each composite optical fiber span, each composite optical fiber span having a length of at least 50 km. Each composite optical fiber span also includes a first optical fiber and a second optical fiber. When the second optical fiber has positive dispersion at a wavelength of 1550 nm, the composite optical fiber span has, at a wavelength of 1550 nm, an average attenuation of less than 0.180 dB/km. When the second optical fiber has negative dispersion at a wavelength of 1550 nm, the composite optical fiber span has, at a wavelength of 1550 nm, an average dispersion with a magnitude from about 2 to about 5 ps/nm/km, an average attenuation of less than 0.205 dB/km, and each composite optical fiber span has an average dispersion slope with a magnitude less than about 0.02 ps/nm | 09-29-2011 |
20110293287 | OPTICAL COMMUNICATION SYSTEM AND OPTICAL COMMUNICATION METHOD - An optical communication system in which optical transmitter | 12-01-2011 |
20120106975 | POWER ALLOCATION IN OPTICAL FIBER TRANSMISSION - Disclosed herein is a scheme for transmitting a composed optical signal | 05-03-2012 |
20120141137 | DISPERSION COMPENSATION DESIGN METHOD AND DISPERSION COMPENSATION DESIGN SYSTEM - A dispersion compensation design system includes a changing unit setting a changed value for the amount of dispersion compensation for a span connecting nodes constituting an optical network; a path classification unit determining whether respective paths in the optical network are capable of transmission with the changed value and classifying one or more of the paths as second category paths based on the determination results; an updating unit updating the amount of dispersion compensation with the changed value if the number of the second category paths in the latest classification result is less than the number of the second category paths in the retained previous classification result; and a repeating unit that, if not all of the paths in the optical network are capable of transmission, prevents use of combinations of amounts of dispersion compensation applied to the spans in the second category paths in the latest classification result. | 06-07-2012 |
20120201546 | PRE-EQUALIZATION OPTICAL TRANSMITTER AND PRE-EQUALIZATION OPTICAL FIBER TRANSMISSION SYSTEM - A pre-equalization optical transmitter includes: an RZ conversion circuit for generating an RZ-type input data sequence based on an NRZ-type input data sequence and a clock that is twice the speed of the NRZ-type input data sequence; a digital filter for generating pre-equalized data by a convolution operation between the RZ-type input data sequence and a desired transfer function corresponding to the wavelength dispersion of an optical fiber transmission path; D/A converters for performing D/A conversion on the pre-equalized data to output analog pre-equalized data; and a vector modulator for modulating light from a laser light source based on the analog pre-equalized data to output an RZ-type optical signal. | 08-09-2012 |
20130223851 | Dispersion-Compensating System And Dispersion-Compensating Fiber with Improved Figure of Merit - A dispersion-compensating system and a dispersion-compensating fiber have an improved figure of merit and effective area. The dispersion-compensating system comprises a bulk dispersion-compensating module for providing optical-domain bulk dispersion compensation for an optical signal transmission. Additionally, the system may further comprise residual dispersion compensation, which can be performed in the electrical domain following coherent detection of both amplitude and phase of an optical signal. The dispersion-compensating fiber comprises an up-doped core region; a down-doped trench; an up-doped ring; and an outer cladding, and is configured to have a high figure of merit (FOM). | 08-29-2013 |
20140003821 | OPTICAL TIME DOMAIN REFLECTOMETER SYSTEMS AND METHODS USING WIDEBAND OPTICAL SIGNALS FOR SUPPRESSING BEAT NOISE | 01-02-2014 |
20140308046 | Compensation for Optical Multi-Path Interference - Systems and methods for optical multi-path interference (MPI) compensation are provided. In an embodiment, a mean MPI signal representing a mean amplitude of the MPI in an input signal is generated and subtracted from a first estimate of transmitted amplitude of the input signal to generate a mean MPI compensated estimate of transmitted amplitude. The mean MPI compensated estimate of transmitted amplitude is sliced to generate a decision of transmitted amplitude of the input signal. The mean MPI signal can be generated using a mean MPI feedback loop or using an iterative feed-forward process. In another embodiment, mean MPI levels corresponding to respective transmitted intensity levels are generated and used to control slice levels of a slicer in order to compensate for MPI. | 10-16-2014 |
20150104189 | COMPENSATION APPARATUS AND METHOD FOR INTER-CHANNEL NONLINEAR DAMAGE - A compensation apparatus and method for inter-channel nonlinear damage are disclosed where the apparatus includes: an iteration parameter determining unit configured to determine an iteration step of cross-phase modulation damage compensation performed in each channel in a multichannel optical fiber transmission link; an estimating unit configured to divide an optical fiber transmission link in each iteration step of each channel into one or more optical fiber segments, and perform cross-phase modulation damage estimation at a position in each optical fiber segment where the nonlinear damage is maximal; and a first compensating unit configured to perform cross-phase modulation damage compensation according to the result of the cross-phase modulation damage estimation. By performing cross-phase modulation damage estimation at a position in each optical fiber segment where the nonlinear damage is maximal, cross-phase modulation damage compensation may be performed effectively, and performance of the communication system may be improved. | 04-16-2015 |
20150295649 | METHOD AND SYSTEM FOR PERFORMING FIBER NONLINEARITY COMPENSATION FOR OPTICAL 16QAM - A method for reducing link fiber nonlinearities executed by a processor. The method includes decomposing a high order quadrature amplitude modulation (QAM) input into a plurality of sub-components. The method includes applying a plurality of logical operations to the plurality of sub-components. The method includes determining a non-linear compensation term based on the applying the plurality of logical operations to the plurality of sub-components. | 10-15-2015 |
20150311978 | OPTICAL DISPERSION COMPENSATION DEVICES - Optical dispersion compensation devices are provided herein that are based on one or more optical ring resonators. The degree of dispersion compensation can be selected by controlling the degree of under-coupling and by tuning physical properties of the optical ring resonators. In a first implementation, an optical ring resonator under-coupled to an optical throughput bus can be used to provide positive or negative dispersion compensation depending on tuning of the optical ring resonator, which widens the dispersion window. In a second implementation, an over-coupled optical ring resonator can be added to the optical throughput bus to provide a cascaded filter. In a third implementation optical ring resonators arranged in series between an optical input bus and an optical output bus can be used to both tune dispersion compensation and provide demultiplexing. | 10-29-2015 |
20160050017 | ADAPTIVE OPTICAL CHANNEL COMPENSATION - In an adaptation module relating generally to adaptive optical channel compensation, an analysis module is coupled to receive a first data signal and a second data signal and coupled to provide first information and second information. A comparison module is coupled to compare the first information and the second information to provide third information. An adjustment module is coupled to receive the third information to provide fourth information to compensate for distortion in the second data signal with reference to the first data signal. The second data signal is associated with a conversion of the first data signal to an optical signal for communication via an optical channel. | 02-18-2016 |
20180026720 | Frequency Domain Equalization Method | 01-25-2018 |
398148000 | Using dispersion compensation optical fiber (e.g., DCOF) | 4 |
20090087190 | OPTICAL COMMUNICATIONS - A dispersion management system for soliton or soliton-like transmission systems comprises a length of optical fibre (L) in which a plurality of sections (l) made up of components (N, A) of opposite sign dispersions are concatenated together. The duration of the dispersion compensation phase is short in comparison with the propagation interval in the remainder of the system and that the path average dispersion is anomalous. | 04-02-2009 |
20090142070 | Methods and apparatus for supporting fiber span loss and dispersion measurements in the presence and absence of dispersion compensation elements - An example embodiment of the invention includes a method and apparatus for supporting fiber span loss and dispersion measurements in the presence or absence of dispersion compensation elements (DCE). The technique may be used to configure a network link by accessing an optical signal at an ingress side of a connection point for a DCE coupling an egress side of a fiber span at the ingress side of the DCE to an optical amplifier at a connection point for an egress side of the DCE. The technique may include determining chromatic dispersion of the fiber span based on the optical signal and reporting information associated with chromatic dispersion. As a result, the technique may be used, for example, during initial system installation when user data signals and the DCE are not present as well as after the network begins carrying user traffic and after a DCE has been installed. | 06-04-2009 |
20090232512 | SYSTEMS AND METHODS FOR CHIRP CONTROL OF A DUAL ARM Z-MODULATOR TO MINIMIZE DISPERSION EFFECT OF FIBER PLANT - The present invention provides systems and methods for chirp control of a dual arm Z-modulator to minimize dispersion in the fiber plant. The chirp control is based upon a real-time control loop based upon performance monitoring data between a transmitter and a receiver. Advantageously, the present invention enables improved performance in high-speed optical systems, and in some cases can eliminate or minimize the need for external dispersion compensation fiber (DCF). | 09-17-2009 |
20120148259 | Dispersion Management in Optical Networks Including Both Coherent and Direct Detection Receivers - Dispersion may be managed in an optical network by allowing accumulation of dispersion to at least ten thousand ps/nm, and several tens of thousands of ps/nm in some embodiments. The accumulated dispersion may be returned to zero or near zero at a receiver and/or at one or more branch paths coupled to the transmission path. | 06-14-2012 |
398149000 | Using equalizing filter (e.g., interferometer, grating) | 14 |
20100046958 | System and Method For Reducing Memory Requirements For Electrical Domain Compensation of Intra-Channel Nonlinearity In An Optical Communications System - A digital filter is provided for processing an electrical input signal to be conveyed through an optical communications system. The processing generates a predistorted electrical signal using a compensation function that substantially mitigates for intra-channel non-linearity imparted to the communications signal by the optical communications system. The digital filter has a memory having a limited size storing a reduced data set used for approximating an original, unreduced data set used to implement the compensation function. The reduced data set is used for the digital filter to apply the compensation function to mitigate the intra-channel non-linearity over longer transmission distances of the optical communications system than would be possible without the use of the reduced data set. | 02-25-2010 |
20100061738 | Signal Processor for Compensating for Optical Fiber Chromatic Dispersion - A signal processor for compensating for optical fibre chromatic dispersion comprising encoding means ( | 03-11-2010 |
20100183316 | Methods and Systems for Dynamic Equalization Delay Passive Optical Networks - Systems and methods according to these exemplary embodiments provide for methods and systems improving the protocol efficiency in passive optical networks. Additionally, methods and systems for calculating and transmitting an equalization delay change message are described. | 07-22-2010 |
20100221017 | Method and System for Optimum Channel Equalization From a SERDES to an Optical Module - Certain aspects of a method and system for optimum channel equalization between a host Serializer-Deserializer (SerDes) and an optical module may compensate and reduce dispersion loss along an electrical transmit path of a transmitter and an optical transmit path coupled to the transmitter via pre-emphasis. The data degradation as a result of the dispersion loss along the electrical transmit path of the transmitter and the optical transmit path coupled to the transmitter may be recovered by equalizing signals received via an electrical receive path of a receiver communicatively coupled to the transmitter. | 09-02-2010 |
20100232802 | OPTICAL TRANSMISSION SYSTEM WITH OPTICAL CHROMATIC DISPERSION COMPENSATOR - Optical transmission system ( | 09-16-2010 |
20100232803 | Integrated Equalizer and Michelson Interferometer Structure for Inter-Symbol Interference-Suppressed colorless DPSK demodulation - An optical device includes an interferometer for a received optical differential phase shift keying DPSK signal, and an equalizer integrated with the interferometer in a manner for reducing from optical filtering effects an interference by signal bits of the DPSK signal with signal bits of a contiguous DPSK signal. The interferometer is a Michelson delay interferometer type, but can also be a Mach-Zehnder delay interferometer type on fiber, waveguide or other optical structure. The equalizer is a Fabry-Perot type equalizer, but can be a ring resonator type or a fiber based equalizer. | 09-16-2010 |
20110064419 | OPTICAL DEVICE AND METHOD FOR OPTICAL FREQUENCY MODULATION TO OPTICAL AMPLITUDE MODULATION CONVERSION - An optical device comprising an optical device comprising a Mach-Zehnder interferometer having a first 2×2 optical coupler, a second 2×2 optical coupler, a first optical arm, and a second optical arm. The first and second arms connecting corresponding pairs of optical ports of the first and second 2×2 optical couplers. The second optical arm has a longer optical path than the first arm. The device also comprises one or more optical resonators optically coupled to the first optical arm and an optical splitter. The optical splitter is coupled to deliver a portion of an input optical signal to one port of the first 2×2 optical coupler and to deliver a remaining portion of the input optical signal to one port of the second optical coupler. | 03-17-2011 |
20110135314 | Waveguide Optically Pre-Amplified Detector with Passband Wavelength Filtering - The invention describes an integrated-photonics arrangement, implementable in a multi-guide vertical integration (MGVI) structure composed from III-V semiconductors and grown in one epitaxial growth run, allowing for the integration of semiconductor optical amplifier (SOA) and PIN photodetector (PIN) structures within a common wavelength-designated waveguide of the plurality of the vertically integrated wavelength-designated waveguides forming the MGVI structure. The integration includes a wavelength filter integrated between the SOA and PIN to reduce noise within the PIN arising from ASE generated by the SOA. In exemplary embodiments of the invention, the wavelength filter is integrated into MGVI structure either within a common wavelength designated waveguide or within the wavelength-designated waveguide. Further in other embodiments the wavelength filter is provided by a thin-film filter abutting a facet of the integrated-photonics arrangement wherein optical signals are coupled by optical waveguides and/or additional optical elements such as a multimode interference device. | 06-09-2011 |
20120002977 | ADAPTIVE EQUALIZATION IN COHERENT FIBER OPTIC COMMUNICATION - An embodiment of the invention is a technique to equalize received samples. A coefficient generator generates filter coefficients using an error vector and input samples. A filter stage generates equalized samples from input samples using the filter coefficients. The received samples are provided by a receiver front end in an optical transmission channel carrying transmitted symbols. Other embodiments are also described. | 01-05-2012 |
20120039616 | SYSTEM AND METHOD FOR ADMINISTRATION OF DISPERSION COMPENSATION MODULES - An optical network contains dispersion compensation modules with Fiber Bragg Gratings. A photo detector behind the Fiber Bragg Grating detects the not reflected rest of the gratings input signal and therefore the dispersion compensation modules input signal. This information is used to reduce the expenditure and to avoid errors of configuration or administration of the dispersion compensating subsystem of the optical network. | 02-16-2012 |
20130287408 | OPTICAL RADIATION SIGNAL GENERATING DEVICE AND TRANCEIVING SYSTEM, AND METHOD OF GENERATING AN OPTICAL RADIATION SIGNAL - A method of generating an optical radiation signal is to be implemented by an optical radiation signal generating device including a dual beam generating unit for receiving an original optical input signal, and a second-order fiber Bragg grating (FBG). The dual-beam generating unit is configured to generate, from the original optical input signal, first and second optical input signals having a phase difference therebetween. The second-order FBG is configured to receive the first and second optical input signals, and to radiate an optical radiation signal by interference between the first and second optical input signals. | 10-31-2013 |
20140079407 | UPDATING APPARATUS AND METHOD FOR EQUALIZER COEFFICIENT, RECEIVER AND OTPICAL COMMUNICATION SYSTEM - The present invention provides an updating apparatus and method for an equalizer coefficient, receiver and optical communication system. The updating method comprises: receiving an optical signal transmitted by a transmitter in an optical communication system, the optical signal comprising transmission data and a constant modulus signal for updating a coefficient of an equalization filter; performing coherent detection and analog-to-digital conversion on the optical signal, so as to obtain a digital electric signal; and updating the coefficient of the equalization filter at a symbol corresponding to the constant modulus signal in the digital electric signal. With the embodiments of the present invention, not only the coefficients of the equalizer may be optimized, but also being adapted to signals in various modulation formats, and the complexity of the channel equalization may be lowered as well. | 03-20-2014 |
20140363173 | DAC-BASED OPTICAL MODULATOR AND DEMODULATOR - Methods, systems, and devices are described for modulating and demodulating data on optical signals. During modulation, at least one stream of symbol mapped bits is filtered with at least one pulse shaping filter to reduce a bandwidth of the stream of bits and to pre-compensate for at least one identified non-ideal transmission condition. The filtered bits are modulated onto a waveform in the digital domain, and the modulated filtered bits are transmitted to digital-to-analog converter. The output of the digital-to-analog converter is converted to an optical signal. During demodulation, a received optical signal is sampled at a first sampling rate at an ADC, downsampled to a lower sampling rate for filtering, filtered with at least one discrete pulse-shaping filter, upsampled for equalization and demodulation, and then equalized and demodulated. | 12-11-2014 |
20160164615 | SYSTEM FOR CONTINUOUSLY ACTIVE STABILIZATION OF INTERFEROMETERS IN QUANTUM TIME-BIN ENTANGLEMENT DISTRIBUTION - Provided are methods and systems for controlling a phase characteristic of entangled photon pairs. The phase characteristic may be a relative phase difference between photons of the entangled photon pair. Also provided are methods and systems for stabilizing distributed interferometers used in quantum communication systems. | 06-09-2016 |