| Entries |
| Document | Title | Date |
|---|
| 20130028604 | OPTICAL ADD/DROP MULTIPLEXER - An optical add/drop multiplexer including one or more optical drop multiplexers connected in free space or fused by optical fiber pigtails, a wavelength blocker with an input port connected to an output port of the optical drop multiplexer through the fusion of the fiber pigtails, one or more optical add multiplexers connected in free space or fused by fiber pigtails, a digital signal processor, an analog-to-digital signal converter, a digital-to-analog converter, and a plurality of electronic control and feedback loops for tuning and scanning an optical wavelength. | 01-31-2013 |
| 20110182582 | JOINT SAMPLE RATE CONVERSION AND CD COMPENSATION IN FREQUENCY DOMAIN FOR COHERENT POLMUX - A combined CD compensation and sample rate conversion method performed in the frequency domain. | 07-28-2011 |
| 20130028603 | METHOD AND APPARATUS FOR PERFORMING TEMPORAL POLARIZATION INTERLEAVING IN AN OPTICAL TRANSMITTING SYSTEM - An optical signal transmitting system, comprising: an optical transmitter including one or more input terminals and an output terminal; and a temporal polarization interleaver including an input terminal and an output terminal, wherein the output terminal of the optical transmitter is communicatively coupled to the input terminal of the temporal polarization interleaver, wherein: the optical transmitter is configured to receive one or more input signals through its one or more input terminals, generate an output signal using the one or more input signals, the output signal including a x-polarized tributary and a y-polarized tributary that is pulse-to-pulse aligned with the x-polarized tributary, and transmit the output signal to the temporal polarization interleaver; and the temporal polarization interleaver is configured to receive the output signal from the optical transmitter and cause a predefined phase delay to one of the x-polarized tributary and the y-polarized tributary. | 01-31-2013 |
| 20090196610 | Optical reception apparatus compatible with DQPSK polarization multiplexing format - In the optical reception apparatus, a DQPSK polarization multiplexed signal light (S) input thereto is split into horizontally/vertically polarized signal lights (S | 08-06-2009 |
| 20100150555 | Automatic polarization demultiplexing for polarization division multiplexed signals - Method and apparatus are provided for polarization demultiplexing for a Polarization Division Multiplexed (PDM) signal stream in the optical domain. The optical PDM signal stream includes a first channel representing a first data stream and a second channel representing a second data stream, a time delay between the first channel and the second channel. A Polarization Beam Splitter (PBS) demultiplexes an optical PDM signal into the first channel and the second channel. An associated processing block obtains one of the channels and provides a Polarization Controller with for a control signal corresponding to the power level of the low frequency portion of the RF spectrum of the channel obtained. Based on the control signal, the Polarization Controller adjusts a state of polarization of the optical PDM signal stream that is provided to the PBS for demultiplexing. | 06-17-2010 |
| 20110194855 | SUPERIMPOSED TRAINING AND DIGITAL FILTERING COHERENT OPTICAL RECEIVERS - In a polarization-multiplexing optical communications system, a method and system for coherent reception of polarization-multiplexed optical communications. Training and data sequences are recovered from a plurality of orthogonally polarized signals, such that training and data sequences may be used on a single channel without loss of spectral efficiency. This is accomplished by estimating a channel response for each orthogonally polarized signal based on the mean of the signal and distinguishing between a data sequence and a training sequence in each orthogonally polarized signal. Such distinguishing is accomplished according to an iterative linear minimum mean-square equalization based on the respective channel response estimate. | 08-11-2011 |
| 20130077973 | SPECTRALLY EFFICIENT MODULATION FOR AN OPTICAL-TRANSPORT SYSTEM - An optical transport system having an optical add-drop multiplexer configured to reduce inter-channel crosstalk by driving Mach-Zehnder pulse carvers in its optical transmitters with electrical drive signals whose swing range is smaller than voltage 2V | 03-28-2013 |
| 20130034354 | POLARIZATION-MULTIPLEXED SIGNAL RECEIVER, POLARIZATION MULTIPLEXING SYSTEM AND POLARIZATION-MULTIPLEXED SIGNAL RECEIVING METHOD - A polarization-multiplexed signal receiver includes a polarization adjustment unit to adjust a polarization state of inputted polarization-multiplexed signal, which is carrying signal data on each of two polarized waves being inputted, based on a control signal and to output the adjusted polarization-multiplexed signal, an optical signal reception unit to convert the polarization-multiplexed signal having the adjusted polarization state into an analog electric signal and output the analog electric signal, | 02-07-2013 |
| 20100098420 | POLARIZATION MONITORING IN POLARIZATION DIVISION MULTIPLEXING IN OPTICAL COMMUNICATIONS - Systems and techniques for optical communications based on polarization division multiplexing are described. | 04-22-2010 |
| 20120183295 | Polarization Diversity with Portable Devices via Wavefront Muxing Techniques - A novel terrestrial wireless communications technique for terrestrial portable terminals including hand-held mobile devices and fixed wireless instruments, utilizing a spoke-and-hub communications system, having a plurality of individual hubs and/or base-stations all in communications with the portable terminals. The portable terminals and the hubs are assigned to use incompatible polarity formats in terms of circularly polarity (CP) and linearly polarity (LP). In forward links, a signal processed by the LP ground telecommunications hubs is radiated through multiple antennas with various LP polarities to an individual CP user simultaneously. The multiple paths are organized via assignments of a plurality of polarities, frequency slots, and directions by wavefront multiplexing/demultiplexing techniques such that the same communications assets including frequency spectrum may be re-used by other users. The same polarity diversity methods can be extended to peer-to-peer communications. | 07-19-2012 |
| 20100104284 | System, method and apparatus for joint self phase modulation compensation for coherent optical polarization-division-multiplexed orthogonal-frequency division-multiplexing systems - System, apparatus and method of optical communication are provided for performing digital compensation of the self-phase modulation (SPM) effect experienced by a polarization-division multiplexed (PDM) orthogonal frequency-division multiplexed (OFDM) signal in fiber transmission by compensating a complex digital waveform representing one orthogonal polarization component of the optical PDM-OFDM signal based on both digital waveforms representing two orthogonal polarization components of the PDM-OFDM signal. The compensation of the digital waveform may be further based on an anticipated mean total nonlinear phase shift experienced by the signal during fiber transmission due to SPM. The compensation may be divided into pre-compensation at the PDM-OFDM transmitter and post-compensation at the PDM-OFDM receiver. The fiber transmission link preferably includes a pre-dispersion compensation module, distributed inline dispersion compensation modules, and a post-dispersion compensation module arranged in a judiciously chosen manner. | 04-29-2010 |
| 20130084069 | DIGITAL LIGHT PATH LABELING SYSTEM WITH DUAL POLARIZATION QUATERNARY PHASE-SHIFT KEYING MODULATION - A method and system for encoding and determining labels in a Dual Polarization (DP) Quaternary Phase Shift Keying (QPSK) signal is provided. A label frame, signature sequence, and data payload are combined using a complementary constant-weight code encoding (CCWC) encoder, the output of which is deinterleaved and differentially precoded to generate a polarized tributary of a DP-QPSK signal. This encoding can be duplicated for a second tributary of the DP-QPSK signal. The label can be determined using one or more polarizers and corresponding low-speed photodetectors, each applied to a copy of the DP-QPSK signal. The strongest output of the photodetectors is then used to determine the label. Alternatively, the DP-QPSK signal can be viewed as having XI, XQ, PH, and PV tributaries. These tributaries can then be translated into XI, XQ, YI, and YQ tributaries are encoded into a standard DP-QPSK signal. | 04-04-2013 |
| 20100142952 | ADAPTIVE CROSSING FREQUENCY DOMAIN EQUALIZATION (FDE) IN DIGITAL POLMUX COHERENT SYSTEMS - A method for the polarization independent frequency domain equalization (FDE) on polarization multiplexing (POLMUX) coherent systems employing an adaptive crossing FDE which advantageously produces CD compensation, PMD compensation and PolDeMux within one functional block of a digital signal processor (DSP). | 06-10-2010 |
| 20100142951 | RECEPTION OF SIGNALS TRANSMITTED OVER A DISPERSIVE OPTICAL CHANNEL - A receiver for recovering transmitted information carried by a received optical signal that has been affected by dispersion includes an optical splitter having an input port arranged to receive the received optical signal, and a plurality of output ports. A proportion of optical power at the input port is transmitted to each of the output ports. A plurality of optical detectors is operably connected to respective output ports of the optical splitter, for generating a corresponding plurality of electrical signals. Optical phase shifters are disposed between the output ports of the optical splitter and respective optical detectors. As a result, each optical phase shifter applies a frequency dependent phase shift to an optical signal passing therethrough. An electronic processor includes analog and/or digital electronic components configured to combine two or more of the plurality of electrical signals, or information recovered separately therefrom, in order to provide improved accuracy or reliability of information recovery as compared with detecting and processing only the received optical signal. The receiver is advantageously able to mitigate the effects of frequency-dependent fading which may occur in intensity modulation/direct detection optical transmission systems due to dispersion in optical transmission paths. | 06-10-2010 |
| 20130051800 | SYSTEM FOR INTEGRATION OF CHANNELS WITH QUANTUM INFORMATION IN COMMUNICATION NETWORKS - System for integration of channels with quantum information in communication networks. The network includes fibre-optic segments and conventional equipment, whilst a quantum key distribution (QKD) system has devices for the exchange of information by a quantum channel. The system includes at least one filter for each one of the exchange devices and at least one unit for managing conventional and quantum channels that reduces the noise in quantum channels and has at least the following functions: attenuation of insertion power of conventional channels in the network; different polarizations in the various conventional and quantum channels; and changes of wavelength assignment in not only conventional but also quantum channels. | 02-28-2013 |
| 20120219294 | DIGITAL SIGNAL-TO-SIGNAL BEAT NOISE REDUCTION FOR FILTER-LESS COHERENT RECEIVING SYSTEM - Systems and methods are disclosed for a filter-less coherent receiving system with a filter-less coherent receiver frontend; a signal-signal beat-noise detector coupled to the filter-less coherent receiver frontend; and a real-time processor coupled to the filter-less coherent receiver frontend and the signal-signal beat-noise detector to reject signal-signal interference. | 08-30-2012 |
| 20130071119 | COMMUNICATION THROUGH PRE-DISPERSION-COMPENSATED PHASE-CONJUGATED OPTICAL VARIANTS - An apparatus comprises an optical transmitter that comprises a processor and at least one optical modulator. The processor is configured to generate electronic representations of at least two pre-dispersion-compensated phase-conjugated optical variants carrying a same modulated payload data for transmission. The at least one optical modulator is configured to modulate the electronic representations, wherein an amount of dispersion induced on the pre-dispersion-compensated phase-conjugated optical variants depends on an accumulated dispersion (AD) of a transmission link through which the pre-dispersion-compensated phase-conjugated optical variants are to be transmitted. The amount of dispersion induced on the phase-conjugated optical variants may be approximately −AD/2, where AD is the accumulated dispersion of the transmission link. The pre-dispersion-compensated phase-conjugated optical variants are different from one another in one or more dimensions such as the polarization of light, the time of transmission, the spatial localization, the optical carrier wavelength, or the subcarrier frequency during transmission. | 03-21-2013 |
| 20120189306 | MULTI-LASER TRANSMITTER OPTICAL SUBASSEMBLIES FOR OPTOELECTRONIC MODULES - Multi-laser transmitter optical subassemblies (TOSAs) for optoelectronic modules. In one example embodiment, a multi-laser TOSA includes first and second lasers configured to generate first and second optical signals, respectively, a polarization beam combiner (PBC), first and second collimating lenses positioned between the first and second lasers, respectively, and the PBC, a half waveplate positioned between the first laser and the PBC, and a focusing lens. The half waveplate is configured to rotate the polarization of the first optical signal. The PBC is configured to combine the first and second optical signals and transmit the combined first and second optical signals toward the focusing lens. | 07-26-2012 |
| 20120224852 | System, Method, and Apparatus for High-Sensitivity Optical Detection - An apparatus transmits data using a format where information bits intended for transmission are mapped into symbols each carrying a plurality of bits, some of which are encoded through pulse position modulation (PPM) format and the rest of which are encoded through an additional modulation format on each PPM pulse. The additional modulation format for the PPM pulse may be at least one of a polarization-division-multiplexed (PDM) modulation, phase-shift keying (PSK) modulation, polarization shift keying (PolSK) modulation, amplitude modulation (AM), quadrature-amplitude modulation (QAM) modulation, or a combination thereof. In one embodiment, the additional modulation of the PPM pulses is through polarization-division-multiplexed quadrature-phase-shift keying (PDM-QPSK). The unique combined use of PDM-QPSK and PPM produces much higher receiver sensitivity than either PPM or PDM-QPSK alone. | 09-06-2012 |
| 20090232500 | TRANSAMPLIFIER, SYSTEM AND METHOD FOR AMPLIFICATION OF OPTICAL SIGNALS AT PLURAL WAVELENGTHS - Disclosed herein are embodiments of a device, method of use and system for an analog multi-wavelength transamplifier. The transamplifier embodiments described herein allow the use of multiple wavelengths to segment logical service groups, such as for use in a CATV distribution system and a FTTH system having a broadband overlay. Improved optical signal power performance can be achieved by using direct modulating transmitters and maintaining polarization of the optical signals that are modulated by a phase modulator, such as an external waveguide. | 09-17-2009 |
| 20120237221 | COHERENT OPTICAL SIGNAL PROCESSING - Coherent optical signal processing is performed in a coherent receiver (or diagnostic/testing apparatus) that converts an amplitude and/or angle-modulated optical signal into two electrical signals. A simple receiver can only detect one phase of the signal and only the polarization that is aligned with a local oscillator laser polarization. To detect both phases and both polarizations, two sets of two interferometers, one each with a π/2 phase shift are required. Coherent optical signal processing methods, apparatus, techniques, etc. are disclosed that include individual components comprising a polarization combiner, a Savart device and photodetection apparatus with substantially reduced temperature and alignment sensitivity operating in optical communication systems and/or subsystems. The various embodiments can be used alone or in such combinations to provide improved coherent optical signal processing in a receiver. | 09-20-2012 |
| 20120063781 | SYSTEM AND METHOD FOR REDUCING POLARIZATION DEPENDENT LOSS CROSS-TALK EFFECTS - In accordance with the present disclosure a system for reducing polarization dependent loss (PDL) of an optical signal comprises a delay module coupled to one or more PDL inducing network elements of an optical network. The delay module is configured to time interleave a first polarization component with respect to a second polarization component of the optical signal. The time interleaving reduces interference caused by cross-talk components associated with the first and second polarization components and induced by the PDL of the PDL inducing elements. | 03-15-2012 |
| 20120189307 | MODULATOR WITH MARKING OF POLARIZATION - A modulator with polarization marking comprising two input ports for receiving two optical signals at one wavelength, and exhibiting essentially perpendicular optical polarization states, capable of phase-modulating those signals with data signals and of combining them with polarization, characterized in that it comprises a source of phase overmodulation for overmodulating the phase of one of said two optical signals, said phase overmodulation exhibiting a modulation frequency substantially lower than the modulation frequency of said data signals. A method and a coherent receiver are also disclosed. | 07-26-2012 |
| 20100266282 | Parallel Digital Coherent Detection Using Symmetrical Optical Interleaver and Direct Optical Down Conversion - A method includes modulating lightwaves to provide first and second OFDM signal sidebands at a first polarization direction and first and second OFDM signal sidebands at a second polarization direction, and combining sidebands that are oppositely positioned and joined from the first and second OFDM signal sidebands at each polarization direction to provide a polarization multiplexing OFDM signal. | 10-21-2010 |
| 20110299852 | OPTICAL TRANSMISSION AND RECEPTION SYSTEM, OPTICAL TRANSMITTING AND RECEIVING APPARATUS, AND OPTICAL TRANSMISSION AND RECEPTION METHOD - An optical transmission and reception system in which a plurality of tributary signals are converted into multilevel modulated light for transmission and reception. An apparatus for transmitting multilevel modulated light includes: FECs which perform error correction processing including addition of a tributary identifier; and a GEAR BOX which performs rate conversion on the processed signals. An apparatus for receiving multilevel modulated light includes: a 20G DQPSK REC which separates received multilevel modulated light into received tributary signals and outputs the signals to respective output systems; the GEAR BOX which performs rate conversion on the received tributary signals; the FECs which extract tributary identifiers from the received tributary signals; a TIM which compares tributary identifiers defined for the respective output systems in advance with the tributary identifies extracted; and a tributary selector which gives an instruction to change correspondence between the received tributary signals and the output systems if the result of comparison is a mismatch. | 12-08-2011 |
| 20110274429 | METHOD AND APPARATUS FOR PHASE SHIFT KEYED OPTICAL COMMUNICATIONS - A burst-mode differential phase shift keying (DPSK) communications system according to an embodiment of the present invention enables practical, power-efficient, multi-rate communications between an optical transmitter and receiver. An embodiment of the system utilizes a single interferometer in the receiver with a relative path delay that is matched to the DPSK symbol rate of the link. DPSK symbols are transmitted in bursts, and the data rate may be varied by changing the ratio of the burst-on time to the burst-off time. This approach offers a number of advantages over conventional DPSK implementations, including near-optimum photon efficiency over a wide range of data rates, simplified multi-rate transceiver implementation, and relaxed transmit laser line-width requirements at low data rates. | 11-10-2011 |
| 20090202243 | Direct Detection For Receiving Polarization Multiplexing Signals - There is provided a method for detecting optical signals comprising employing a photo diode to both directly detect a received optical signal and convert it into an electrical signal for recovery of data bit stream information in the received optical signal, the received optical signal being derived from a separation of two polarization multiplexed optical signals that were combined before being received. | 08-13-2009 |
| 20110293276 | OPTICAL TRANSMITTER AND METHOD FOR CONTROLLING THE SAME - An optical transmitter includes: a first modulator that modulates a first optical signal with a first data signal; a second modulator that modulates a second optical signal with a second data signal; a multiplexer that multiplexes the first optical signal and the modulated second optical signal to output a multiplexed signal; a phase difference data generator that generates a phase difference signal corresponding to a phase difference between the modulated first optical signal and the modulated second optical signal from the multiplexed signal; and a controller that controls the phase difference between the modulated first optical signal and the modulated second optical signal based on the phase difference signal. | 12-01-2011 |
| 20110293275 | Polarization Control in a Photonic Integrated Circuit - The present invention provides a system, apparatus and method to maintain the polarization state of an optical signal propagating within a photonic integrated circuit, or from a first photonic integrated circuit to a second photonic integrated circuit. According to various embodiments of the invention, an optical circuit is provided which includes an optical coupler configured to accept a first optical signal on a first input and a second optical signal on a second input, the second optical signal having a polarization state. The optical coupler may combine the first and second optical signals into an optical output signal. A principle axis of a first end of an optical fiber is may be configured to align with the polarization state of the second optical signal, such that a polarization maintaining connection is established. The polarization state may be a TM polarization state, a TE polarization state, or another polarization state. The optical circuit may include birefringent structures, such as birefringent waveguides and birefringent wavelength selective couplers, to further maintain the polarization of optical signals propagating through the photonic integrated circuits. | 12-01-2011 |
| 20100034537 | FREQUENCY OFFSET POLARIZATION MULTIPLEXING MODULATION FORMAT AND SYSTEM INCORPORATING THE SAME - An apparatus, system and method wherein a polarization multiplexed differential phase shift keying format (POLMUX-DPSK) is provided with offset and bit-interleaved frequency channels and demodulated using a DPSK demodulator. | 02-11-2010 |
| 20120087661 | Long Distance Transmission Of Incoherent Optical Signals In An Optical Network - A method and apparatus of transmitting a 10 G non-return to zero (NRZ) optical signal over a long length of single mode fiber between a 10 G NRZ optical source and a 10 G digital coherent receiver is described. A device receives a 10 G NRZ optical signal from the 10 G NRZ optical source, where the 10 G NRZ optical signal has an accumulated dispersion that is greater than a dispersion tolerance of an incoherent 10 G NRZ optical receiver. The device further recovers the 10 G NRZ optical signal using the 10 G digital coherent receiver. | 04-12-2012 |
| 20090169208 | SYSTEMS AND METHODS FOR THE POLARIZATION INSENSITIVE COHERENT DETECTION AND THE POLARIZATION DIVISION MULTIPLEXED TRANSMISSION OF OPTICAL COMMUNICATION SIGNALS - The present invention relates generally to the transport and processing of optical communication signals. More specifically, the present invention relates to systems and methods for the polarization insensitive coherent detection of optical communication signals with Brillouin amplification of the associated signal carrier and the polarization division multiplexed transmission of optical communication signals without polarization tracking at the associated receiver(s). | 07-02-2009 |
| 20090028563 | OPTICAL TRANSMISSION/RECEPTION DEVICE AND OPTICAL COMMUNICATION SYSTEM USING THE SAME - An optical transmission/reception device includes at least one light emitting portion and at least one light receiving portion on the same substrate. The light emitting portion includes at least a lower multilayer reflector and an active layer provided on the lower multilayer reflector. A metal layer including a plurality of opening portions is provided in an upper portion of the light emitting portion. Each of the opening portions has a size smaller than a light emission wavelength of the light emitting portion. | 01-29-2009 |
| 20090310965 | Optical Transmission System and Device for Receiving an Optical Signal - The invention concerns a device ( | 12-17-2009 |
| 20090290874 | MONITORING APPARATUS AND METHOD FOR POLARIZATION SCRAMBLER AND OPTICAL TRANSMISSION APPARATUS - There are provided a polarized light passing device to pass therethrough specific polarized light, of output light of a polarization scrambler; and a detecting unit to detect a modulation component according to a frequency of a polarization control signal from the light which passes through the polarized light passing device. | 11-26-2009 |
| 20120106962 | POLARIZATION MULTIPLEXING AND TRANSMITTING APPARATUS - A polarization multiplexing and transmitting apparatus generates polarization multiplexed light by multiplexing modulated signal components that having varying intensities and are in polarization states orthogonal to each other. The polarization multiplexing and transmitting apparatus includes a converting unit that converts light generated by a light source into signal components having a varying intensity synchronized with a clock signal input thereto and a varying intensity inversely synchronized with the clock signal, respectively; a modulating unit that modulates the signal components, respectively; and a polarization adjusting unit that orthogonalizes polarization states of the signal components. | 05-03-2012 |
| 20090274460 | DIFFERENTIAL DELAY RECEIVER USING CROSS-POLARIZATION INTERFEROMETER FOR POLMUX-DPSK SYSTEM - A differential delay detection system and method includes an optical splitter to split an incoming optical signal between a first path and a second path. The first path includes a cross-polarization interferometer configured to separately generate polarization independent outputs using split paths and to generate cross-polarization interference outputs, and a polarization demultiplexer configured to combine the polarization independent outputs and the cross-polarization interference outputs from the cross-polarization interferometer with updated coefficients received from the second path to remove the cross-polarization mixed signals, The second path includes a training signal receiver configured to compute the updated coefficients and output the updated coefficients to the polarization demultiplexer. | 11-05-2009 |
| 20110170869 | POLARIZATION MULTIPLEXING TRANSMITTER AND TRANSMISSION SYSTEM - A polarization multiplexing transmitter which generates polarization-multiplexed signals which are arbitrarily polarization-scrambled at high speed, without adding a polarization modulator and a polarization scrambler. In the transmitter, an orthogonally polarized signal generator includes two optical modulators which modulate the electric fields of optical signals and generate two optical signals with mutually orthogonal polarized waves. The transmitter includes electric field mappers which convert two data strings into electric field signals, polarization mappers which give different polarized waves to the two signals, polarization rotators which rotate the polarized waves of the signals uniformly, a polarization multiplexer which multiplexes the two polarization-rotated signals, a polarization demultiplexer which demultiplexes the multiplexed signal into polarized wave components of optical signals generated by the orthogonally polarized signal generator, and a driver. The optical modulators are driven to make the two demultiplexed electric field signals consistent with the electric fields of optical signals modulated by the modulators. | 07-14-2011 |
| 20110170870 | Method and Device for Stabilizing the State of Polarization of a Polarization Multiplexed Optical Radiation - A device and method for stabilizing the state of polarization of polarization multiplexed optical radiation including an identified channel is disclosed. The device and method comprise providing to the polarization multiplexed optical radiation a first controllable polarization transformation to generate a first transformed optical radiation; detecting a first state of polarization of a first polarized portion with respect to a first polarization parameter; controlling the first controllable polarization transformation so that the first polarization parameter has a predetermined value independent of a polarization state of the polarization multiplexed optical radiation; providing to the first transformed optical radiation a second controllable polarization transformation to generate a second transformed optical radiation; detecting a second state of polarization of a second polarized portion; and controlling the second controllable polarization transformation so that the second state of polarization has a predefined value. | 07-14-2011 |
| 20090103921 | OPTICAL RECEIVER SYSTEMS AND METHODS FOR POLARIZATION DEMULTIPLEXING, PMD COMPENSATION, AND DXPSK DEMODULATION - A simplified optical receiver architecture capable of tracking and demultiplexing polarization-multiplexed signals, dynamically compensating for PMD using a variety of polarization controller technologies, and reducing the number of delay line demodulators by two for both DPSK and DQPSK modulation is illustrated. Once polarization is stabilized at the first stage of the cascaded system of the present invention, subsequent stages can be simplified and cost reduced. | 04-23-2009 |
| 20100111531 | OPTICAL TRANSMISSION/RECEPTION SYSTEM, OPTICAL TRANSMITTER, OPTICAL RECEIVER, AND OPTICAL TRANSMISSION/RECEPTION METHOD - An optical transmission/reception system includes a modulator for modulating light based on data to output signal light; a transmission-side signal processor performing transmission-side digital signal processing which imparts a polarization change to the signal light by the optical modulation with respect to an input signal; an optical transmitter in which the modulator performs the optical modulation based on the input signal subjected to the transmission-side digital signal processing in the transmission-side signal processor; and an optical receiver including a converter converting the signal light inputted from the optical transmitter via a transmission path to a digital electric signal for each polarization component, and a reception-side signal processor performing reception-side digital signal processing which imparts a polarization change having a property substantially inverse to a property of the polarization change in the transmission-side signal processor with respect to the digital electric signal from the converter. | 05-06-2010 |
| 20100111530 | POLARIZATION MODE DISPERSION COMPENSATION AND POLARIZATION DEMULTIPLEXING SYSTEMS AND METHODS FOR OPTICAL TRANSMISSION SYSTEMS - The present disclosure provides polarization mode dispersion compensation (PMDC) and polarization de-multiplexing systems and methods for polarization multiplexed (PolMux) optical transmission systems. The PMDC detects an error signal before a polarization splitter in PolMux systems for controlling polarization controllers (PC) and/or DGDs in the PMDC for return-to-zero (RZ) differential m-phase shift keying (DmPSK) signals. For bit-aligned PolMux systems, the error signal could be the level of clock frequency at one, two, or more times of the baud rate at one polarization. For bit-interleaved PolMux systems, the error signal could be the level of clock frequency at two times of the baud rate at one polarization. The PMDC can operate in PolMux systems with any arbitrary time offset between the two polarizations. The polarization de-multiplexer utilizes error detection at both output arms of a polarization splitter to mitigate PDL impact on any PolMux type of signal. | 05-06-2010 |
| 20110206375 | METHOD, DEVICE, AND SYSTEM FOR OPTICAL POLARIZATION DIVISION MULTIPLEXING OF OPTICAL CARRIER - The method includes: splitting an optical carrier into two or more sets of optical sub-carriers at a receiving end; respectively performing optical PDM on each set of the optical sub-carriers to obtain two sets of to-be-demodulated optical signals; and extracting a part of signals from each set of the to-be-demodulated signals to calculate features characterizing polarization states, controlling feedback signals according to the features, and correspondingly adjusting a polarization state of each set of the optical sub-carriers. With the device combining optical division into two or more sets of sub-carriers with optical PDM, an optical carrier signal can be split in an optical modulation format into four or more sets of signals for processing, and delay interference can be performed directly on an optical wave by using Differential Quadrature Phase Shifted Keying (DQPSK) demodulators to obtain by detection output signals. | 08-25-2011 |
| 20090129778 | RAMAN CANCELLATION AND MANAGEMENT IN CATV TRANSPORT AND DISTRIBUTION VIA RF SPECTRUM INVERSION - Provided herein are at least one embodiment of a system and method for reducing or eliminating crosstalk and associated distortion in a wavelength-division multiplexed optical signal transmitted over a fiber optic network by inversion of the RF signals that are inputs to the system. | 05-21-2009 |
| 20120070149 | COHERENT OPTICAL RECEIVING APPARATUS AND OPTICAL SIGNAL PROCESSING METHOD - Provided is a coherent optical receiving apparatus and an optical signal processing method. The coherent optical receiving apparatus may include an optical hybrid unit to generate an optical signal by combining a first optical signal inputted from an optical transmitting apparatus and a second optical signal inputted from a local oscillator, a polarization demuxer to demultiplex the optical signal outputted from the optical hybridizing unit, a frequency offset compensator to estimate a frequency offset of at least one of even-numbered samples and odd-numbered samples, and to compensate for a frequency offset of the even-numbered samples and a frequency offset of the odd-numbered samples using the at least one estimated frequency offset, and a carver distortion compensator to compensate for phase distortions of the samples for which the compensation for the frequency offset is performed, the phase distortions being generated by the optical transmitting apparatus. | 03-22-2012 |
| 20110142449 | Method And Apparatus For Polarization-Division-Multiplexed Optical Coherent Receivers - The singularity problem of the constant modulus algorithm (CMA) equalizer may be overcome by implementing the CMA equalizer as a two-stage equalizer, with the first stage being a modified version of a CMA equalizer and the second stage being a conventional CMA equalizer. The first stage may be made up of four sub-equalizers, of which only two of the sub-equalizers are independent, i.e., uncorrelated to each other. This first stage equalizer may compensate for PMD. The second stage equalizer is a conventional CMA equalizer made up of four sub-equalizers that are adjusted independently. This second stage equalizer may compensate for polarization-dependent loss (PDL) and any residual CD that is not fully compensated for by a CD compensator before the two-stage equalizer. Advantageously, as the determinant of the first stage never approaches zero, the singularity problem of a conventional CMA single-stage-only equalizer is avoided by the two-stage equalizer. | 06-16-2011 |
| 20110222853 | POLARIZED-WAVE-MULTIPLEXING OPTICAL TRANSMITTER AND CONTROL METHOD OF POLARIZED-WAVE-MULTIPLEXED OPTICAL SIGNAL - A polarized-wave-multiplexing optical transmitter including: an optical combiner generating a polarized-wave-multiplexed optical signal by polarized-wave-multiplexing a first optical modulation signal and a second optical modulation signal; an optical power fluctuation portion fluctuating optical power of the first optical modulation signal and the second optical modulation signal periodically; a total-optical-power detection portion detecting fluctuation amount of total optical power of the polarized-wave-multiplexed optical signal; and an optical power controller reducing an optical power difference between the first optical modulation signal and the second optical modulation signal based on detection result of the total-optical-power detection portion. | 09-15-2011 |
| 20100003028 | FILTER COEFFICIENT ADJUSTMENT APPARATUS - In present invention, a filter coefficient adjustment apparatus is used in a polarization demultiplexer which demultiplexes the input signals by using filters to obtain demultiplexed output signals, said filter coefficient adjustment apparatus being used for adjusting the coefficients of the filters, wherein said filter coefficient adjustment apparatus comprises: an logarithm partial derivative calculation unit for calculating the logarithm partial derivative value of a target probability density function of the demultiplexed output signals when its self-variable value is the present demultiplexed output signal value; a gradient calculation unit for calculating the gradient of a target optimizing function for optimizing the distribution of the multiplexed output signals based on the logarithm partial derivative value calculated by the logarithm partial derivative calculation unit; and a filter coefficient updating unit for updating the coefficients of the filters based on the gradient calculated by the gradient calculation unit. | 01-07-2010 |
| 20100189438 | POLARIZATION MULTIPLEXING OPTICAL RECEIVER AND POLARIZATION MULTIPLEXING OPTICAL TRANSMISSION SYSTEM - A polarization multiplexing optical receiver includes a polarization controller configured to control a polarization state of a polarization multiplexed optical signal; a polarization splitter configured to split the polarization multiplexed optical signal for which the polarization state is controlled by the polarization controller into a first polarization signal and a second polarization signal; a first detector configured to detect an optical power of the first polarization signal and output a first optical power signal representing the optical power of the first polarization signal; a second detector configured to detect an optical power of the second polarization signal and output a second optical power signal representing the optical power of the second polarization signal; and a controller configured to control the polarization controller on the basis of the first optical power signal and the second optical power signal. | 07-29-2010 |
| 20100189437 | Optical receiver and optical reception method compatible with differential quadrature phase shift keying - In an optical receiver according to the present invention, an input signal light subjected to the differential quadrature phase shift keying (DQPSK) is incident on a PANDA type fiber in a linearly polarized state by 45°, so that a delay time difference corresponding to one symbol is generated between orthogonal polarization components in the DQPSK signal light, and then, the signal light is branched by a half mirror into two, to be sent to first and second paths respectively, thereby giving, by a ¼ wave plate disposed on one of the paths, a relative birefringent amount difference of π/2 between the lights propagated through the respective paths. Then, each of the lights propagated through the first and second paths is separated into two orthogonal polarization components by a polarization beam splitter, and the respective polarization components are received by a differential reception circuit so that in-phase components and quadrature components in the DQPSK signal are demodulated. Thus, a small sized and low cost optical receiver capable of stably demodulating the DQPSK signal is provided. | 07-29-2010 |
| 20100178056 | Multi-wavelength coherent receiver with a shared optical hybrid and a multi-wavelength Local Oscillator - An exemplary apparatus for digital coherent detection of a multi-wavelength signal includes a polarization-diversity optical hybrid, at least four Wavelength De-Multiplexing (W-DMUX) filters, 4M detectors, and 4M analog-to-digital converters (ADCs), with M an integer greater than one. The hybrid has a first input for receiving a multi-wavelength signal including M sub-channels at different wavelengths, and a second input for receiving a reference light source including M continuous-wave references at different wavelengths that approximates center wavelengths of the M sub-channels. The hybrid has at least four outputs. A W-DMUX input for each W-DMUX filter is provided a corresponding one of the hybrid outputs, and each W-DMUX filter provides M filtered optical channel outputs. Each detector converts at least one of the filtered channel outputs into a corresponding electrical signal. Each ADC converts one of the electrical signals into a corresponding digital signal. The corresponding digital signals represent the M sub-channels. | 07-15-2010 |
| 20100021163 | METHOD AND SYSTEM FOR POLARIZATION SUPPORTED OPTICAL TRANSMISSION - A method comprising splitting a received optical signal into split optical signals, the split optical signals being at least initially orthogonally polarized, coherently detecting at least one of the split optical signals and generating an electrical signal indicative thereof, and processing said electrical signal, the processing being adapted for received optical signals with orthogonal frequency division multiplexing (OFDM) modulation. A transmission system, a transmitter and a receiver are also provided. | 01-28-2010 |
| 20100239254 | Compensation of Transmission Impairments in Polarization Multiplexed Systems - Systems and methods of compensating for transmission impairment are disclosed. One such method includes receiving a polarization-division multiplexed optical signal which has been distorted in the physical domain by an optical transmission channel, and propagating the distorted polarization-division multiplexed optical signal backward in the electronic domain in a corresponding virtual optical transmission channel. | 09-23-2010 |
| 20090310966 | DIRECT DETECTION RECEIVER USING CROSS-POLARIZATION INTERFEROMETER FOR POLMUX-ASK SYSTEM - A differential delay detection system and method includes an optical splitter to split an incoming optical signal between a first path and a second path. The first path includes a cross-polarization interferometer configured to separately generate polarization independent outputs using split paths and to generate cross-polarization interference outputs, balanced photodetectors to aid in removing cross-polarization beating noise, and a polarization demultiplexer configured to combine the polarization independent outputs and the cross-polarization interference outputs from the cross-polarization interferometer with updated coefficients received from the second path to remove the cross-polarization mixed signals. The second path includes a training signal receiver configured to compute the updated coefficients and output the updated coefficients to the polarization demultiplexer. | 12-17-2009 |
| 20120141128 | Colorless Dense Wavelength Division Multiplexing Transmitters - A dense wavelength-division-multiplexing (DWDM) system, comprising a plurality of laser transmitters, a wavelength division multiplexer (WDM) optically coupled to the laser transmitters and to an output optical transmission media, a coupler optically coupled to the output optical transmission media, an interferometric filter optically coupled to the coupler but not directly to the output optical transmission media, and a light reflector optically coupled to the interferometric filter and not directly to the output optical transmission media. | 06-07-2012 |
| 20090324223 | System, method and apparatus for channel estimation with dual polarization training symbols for coherent optical OFDM - System, apparatus and method of optical communication are provided for performing channel estimation for an optical OFDM system by utilizing correlated dual-polarization training symbols (CDPTS) to offer high system tolerance to fiber nonlinear effects such as cross-phase modulation (XPM) among wavelength-division multiplexed (WDM) channels. An exemplary method includes receiving a pair of dual-polarization or polarization-multiplexed training symbols in an optical polarization-division multiplexed (PDM) orthogonal frequency-division multiplexed (OFDM) signal, and performing channel estimation to obtain an estimated channel matrix for at least a first of a plurality of subcarriers of the PDM-OFDM signal. Channel compensation is performed based on the estimated channel matrix for at least the first subcarrier of the OFDM signal and symbols then decoded. | 12-31-2009 |
| 20110110663 | METHOD, DEVICE, AND SYSTEM FOR REALIZING POLARIZATION MODE DISPERSION COMPENSATION - A method, device, system for realizing polarization mode dispersion (PMD) compensation are provided. The method for realizing PMD compensation includes: de-multiplexing a polarization-multiplexed optical signal, to obtain a first polarization light and a second polarization light; and joint-equalizing the first polarization light and the second polarization light, to obtain a first equalization signal and a second equalization signal. Since the polarization-multiplexed optical signal is de-multiplexed and then joint-equalized, not only the intra-channel symbol interference but also the inter-channel symbol interference during transmission of the polarization-multiplexed optical signal is eliminated, so as to realize the PMD compensation. | 05-12-2011 |
| 20100322627 | DEPOLARISED WDM SOURCE - A device and method for depolarising the total field of a wavelength division multiplexed (WDM) signal is provided. A polarisation maintaining multiplexor combines a plurality of optical signals to form a polarised multiplexed signal. The multiplexed signal is then passed through a differential group delay (DGD) element adapted to modify the polarisation state of one or more optical source signals within the multiplexed signal and thereby to at least partially depolarise the multiplexed signal. | 12-23-2010 |
| 20100322628 | COHERENT OPTICAL RECEIVER - A coherent optical receiver circuit is disclosed in which various components of the optical receiver may be provided or integrated, in one example, on a common substrate. Further integration is achieved by incorporating various optical demultiplexer designs that are relatively compact and conserve space on the surface of the substrate. The optical receiver circuit may be used to demultiplex quadrature phase shift keying (QPSK) optical signals. | 12-23-2010 |
| 20100322631 | Optical receiver integrated on a substrate - A coherent optical receiver circuit is disclosed in which various components of the optical receiver may be provided or integrated, in one example, on a common substrate. Further integration is achieved by incorporating various optical demultiplexer designs that are relatively compact and conserve space on the surface of the substrate. The optical receiver circuit may be used to demultiplex quadrature phase shift keying (QPSK) optical signals. | 12-23-2010 |
| 20100322630 | OPTICAL TRANSMISSION APPARATUS AND METHOD - An optical transmission apparatus including a transmitting OTL processor to rearrange a data string stored in a frame into a plurality of logical lanes, and set a lane ID used to identify in which logical lane a beginning of the data string is arranged among the plurality of logical lanes in a non-scramble area in an overhead of the frame, and a receiving OTL processor to respectively identify the lane IDs included in the data string in the respective physical lanes rearranged, determine a generation state of a bit inversion and a lane replacement for each physical lane, compensate the bit inversion and the lane replacement so that the data string in the respective physical lanes becomes same state as the data string in the respective logical lanes, based on the identified result, and rearrange the compensated data string in the respective logical lanes so as to regenerate the frame. | 12-23-2010 |
| 20110033184 | Side Band Pilot Tone for Digital Signal Processing in Polarization Multiplexed Coherent Optical Communication System - A method comprising generating a plurality of first symbols that correspond to a side band pilot tone (SBPT) signal for a plurality of data streams, mapping the first symbols into a plurality of second symbols that correspond to a plurality of signal components of the polarization multiplexed (PM) optical signal, and transmitting the second symbols in a plurality of data blocks of a PM optical signal. An apparatus comprising at least one processor coupled to a memory and configured to obtain a data block that comprises a plurality of SBPTs in a received PM optical signal, estimate a set of values for a carrier frequency and a polarization state, update a tap weight of a master equalizer based on the estimated set of values, and update a plurality of slave equalizers based on the updated tap weight of the master equalizer. | 02-10-2011 |
| 20110211835 | System and Method for Mitigating Polarization Hole Burning - A system for mitigating the effects of polarization hole burning in an optical communication system. The system includes an optical input signal comprising one or more traffic channels, a measurement module configured to check for the existence of ghost channels around the traffic channels, and a ghost channel generation module configured to generate a ghost channel around the traffic channels from amplified spontaneous emission noise of the optical input signal. | 09-01-2011 |
| 20110085802 | Polarization-multiplexed optical transmission - In optical signal transmission, multiple sets of optical signals which contain data and are associated with at least two polarization states are multiplexed using a single arrayed waveguide grating (AWG). The resulting multiplexed signals are then polarization-multiplexed for transmission. In one embodiment, the AWG is provisioned in a unidirectional mode to multiplex the multiple sets of optical signals. In another embodiment, the AWG is provisioned in a bidirectional mode to multiplex the multiple sets of optical signals. | 04-14-2011 |
| 20110243562 | METHOD AND APPARATUS FOR INTEGRATED WAVEGUIDE TRANSMIT-RECEIVE ISOLATION, FILTERING, AND CIRCULAR POLARIZATION - An radio is provided for transmit-receive isolation filtering and circular polarization (INTRIFPWA) that are sealed within a metal housing of a transmitter, which can be used in microwave communication systems, including satellite based communications systems and terrestrial based microwave communication systems. | 10-06-2011 |
| 20110243561 | FILTER, COHERENT RECEIVER DEVICE AND COHERENT RECEIVING METHOD - The present invention relates to filter, coherent receiver device and coherent receiving method. The filter is used for converting a partial response signal into a full response signal, wherein the filter uses the following transfer function H | 10-06-2011 |
| 20100054737 | Parallel Optical Polarization Tracking - A system to communicate optical data signals in parallel includes an optical splitter to split the data signals into two polarization multiplexed (PM) signals; and two reception channels coupled to the optical splitter, where each reception channel tracks and isolates a PM signal independently. | 03-04-2010 |
| 20110076021 | OPTICAL RECEIVER SYSTEMS AND METHODS FOR POLARIZATION DEMULTIPLEXING, PMD COMPENSATION, AND DXPSK DEMODULATION - A simplified optical receiver architecture capable of tracking and demultiplexing polarization-multiplexed signals, dynamically compensating for PMD using a variety of polarization controller technologies, and reducing the number of delay line demodulators by two for both DPSK and DQPSK modulation is illustrated. Once polarization is stabilized at the first stage of the cascaded system of the present invention, subsequent stages can be simplified and cost reduced. | 03-31-2011 |
| 20110249971 | Polarization fluctuation compensation device and optical communication system - A polarization fluctuation compensation device, when WDM light received by, for example, an optical reception device includes a polarization scrambled optical signal and a non-polarization scrambled optical signal, collects information related to whether optical signals having respective wavelengths are polarization scrambled, obtains a target value of control parameters which are different from each other, according to the speed of polarization fluctuations in the non-polarization scrambled optical signal based on the collected information, and performs reception processing of the non-polarization scrambled optical signal by using a control parameter set as the target value. As a result, an influence of fast polarization fluctuations generated resulting from an interaction between optical signals having respective wavelengths can be reliably compensated for, thereby enabling to realize excellent reception characteristics. | 10-13-2011 |
| 20110103795 | SOFT DECODING OF DATA IN A COHERENT OPTICAL RECEIVER - In a coherent optical receiver receiving a polarization multiplexed optical signal through an optical communications network, a method of compensating noise due to polarization dependent loss (PDL). A Least Mean Squares (LMS) compensation block processes sample streams of the received optical signal to generate symbol estimates of symbols modulated onto each transmitted polarization of the optical signal. A decorrelation block de-correlates noise in the respective symbol estimates of each transmitted polarization and generating a set of decorrelated coordinate signals. A maximum likelihood estimator soft decodes the de-correlated coordinate signals generated by the decorrelation block. | 05-05-2011 |
| 20110076020 | POWER CONTROL OF OPTICAL SIGNALS HAVING DIFFERENT POLARIZATIONS - Consistent with an aspect of the present disclosure, an optical communication apparatus is provided that transmits a WDM signal including a plurality of optical channels, wherein each channel has a corresponding one of a plurality of wavelengths. Each of the plurality of optical channels includes optical signals having first (e.g., TE) and second (e.g., TM) polarizations. In one example, each polarized optical signal is modulated in accordance with an identifying tone. The optical channels are combined onto a waveguide, and an optical tap connected or coupled to the waveguide supplies a portion of the WDM signal including a composite of the optical channels to a photodiode. The aggregate power received by the photodiode includes the power associated with each optical channel, and the power of each channel is the sum of the powers of individual polarized optical signals within that channel. The photodiode converts the received WDM portion including the polarized optical signal portions into corresponding electrical signals. A processor circuit demodulates the electrical signals, identifies the tones, and determines a modulation depth for each tone. Based on the modulation depth, a ratio of the optical powers of one polarized optical signal to another can be calculated, and the optical powers of one or both of the polarized optical signals in each channel can be adjusted so that the optical power ratio has a desired value, e.g., a value substantially equal to one. Thus, one tap and one photodiode may be provided to monitor each polarized optical signal within each WDM channel, thereby reducing costs and yielding a simpler system design. | 03-31-2011 |
| 20110076019 | SYSTEM FOR GENERATING OPTICAL RZ SIGNALS BASED ON ELECTRICAL RZ SIGNALS - Consistent with the present disclosure, polarized optical signals having the same wavelength are modulated in response to ERZ drive signals, to thereby yield corresponding RZ optical signals. Each of the polarized RZ optical signals includes a plurality of RZ transitions wherein the power of the optical signal returns to zero or a minimal power between bits or symbols. The phase or timing of the ERZ drive signals, however, is controlled, so that the RZ transitions in one polarized optical signal remain interleaved with the RZ transitions of the other polarized optical signal. Alternatively, the RZ transitions of the two polarized optical signals may be controlled so that the two are temporally aligned with one another. Thus, the timing of the RZ transitions of one polarized optical signal relative to the other polarized optical signal may be adjusted to optimize system performance. | 03-31-2011 |
| 20110150478 | Receiver Algorithms for Coherent Detection of Polarization-Multiplexed Optical Signals - A digital signal processor (DSP) operating within, for example, an optical receiver wherein the DSP processes complex sample streams derived from a received digitally modulated optical signal, the DSP configured to perform a method comprising: using a filter adaptation algorithm (FAA), processing digitized complex sample streams for each of a sequence of unitary matrix different starting conditions associated with the FAA to establish a converged FAA. | 06-23-2011 |
| 20110150477 | Receiver Algorithms for Coherent Detection of Polarization-Multiplexed Optical Signals - A digital signal processor (DSP) operating within, for example, an optical receiver wherein the DSP processes complex sample streams derived from a received modulated optical signal, the DSP configured to perform a method comprising: processing at least one block of symbols within a complex symbol stream to define a received constellation having symbols located within decision boundaries; and verifying that the received constellation does not exhibit errors by comparing the received constellation to each of a sequence of reference constellations having corresponding phase shifts within an angular ambiguity range of the first constellation. | 06-23-2011 |
| 20100322629 | POLARIZATION BEAM SPLITTER - Consistent with the present disclosure, a polarization multiplexed optical signal having optical signals with both TE and TM polarizations is supplied to an input of a polarization beam splitter (PBS). The PBS includes a first output that supplies TE polarized optical signals and a second output supplies TM polarized optical signals. A first polarizer is coupled to the second output of the PBS to pass the TM polarized optical signals, while rejecting light having other polarizations, such as the TE polarization. A rotator then rotates the light output from the first polarizer, so that such light has a TE polarization. A second polarizer is coupled to the rotator to filter light having a polarization other than the TE polarization. In addition, a third polarizer is coupled to the first output of the PBS in order to filter or block any TM light, for example, that may be output from the PBS with the TE polarized signal. Accordingly, the optical signals in the polarization multiplexed optical signal are effectively filtered, and some are rotated so that each has the same, e.g., TE polarization. Moreover, each optical signal is substantially free from light having extraneous polarizations and may be supplied to an optical hybrid circuit. Data carried by such optical signals may thus be reliably recovered. | 12-23-2010 |
| 20100303462 | OPTICAL DETECTION DEVICE IN WDM-PON AND METHOD FOR SAME - A optical detection apparatus includes: an optical splitting unit configured to split a seed lightwave and split upward signal light generated by an optical network unit, based on the seed lightwave; a first control unit configured to control polarizations of the split seed lightwaves based on a first electrical signal; a second control unit configured to control phases of the split seed lightwaves based on a second electrical signal; an optical coupling and signal conversion unit configured to couple the seed lightwaves, of which the polarization and phase are controlled, and the split upward signal lights, convert the coupled optical signals into the first and second electrical signals, and transfer the first and second electrical signals to the first and second control units, respectively; and a signal detection unit. | 12-02-2010 |
| 20100054738 | CONTROL APPARATUS, POLARIZATION MULTIPLEXING LIGHT MODULATOR, LIGHT TRANSMITTING APPARATUS, AND METHOD OF CONTROLLING POLARIZATION MULTIPLEXING LIGHT MODULATOR - The present invention provides a control apparatus including: an output monitor which monitors polarization-multiplexed output light output from a polarization multiplexing light modulator which modulates light of two systems independent of each other, polarization-multiplexes light signals of the two systems subjected to the light modulation, and outputs the polarization-multiplexed light signals; and a control unit which controls a delay time difference at a stage where the light signals of the two systems forming the polarization multiplexing light modulator are polarization-multiplexed based on a monitor result of the output monitor. The control apparatus controls a delay time difference between polarization channels easily or surely. | 03-04-2010 |
| 20110150479 | Multi-Level Polarization Multi-Level Phase Modulator - An apparatus for use with an optical computation system may comprise a monolithic device with no free space optical components and may include a phase modulator and a polarization modulator. The phase modulator may be configured to receive a beam of light and two digital data streams and operable to modulate the phase of the beam of light to at least four phase states, the at least four phase states representing the two digital data streams. The polarization modulator may be configured to receive two additional digital data streams and the modulated beam of light from the phase modulator and operable to modulate the polarization of the beam of light to at least four polarization states, the at least four polarization states representing the two additional digital data streams. | 06-23-2011 |
| 20090324224 | System, method and apparatus to suppress inter-channel nonlinearities in WDM systems with coherent detection - For optical communications, apparatus and methods are provided for performing dispersion compensation management that suppresses intra-channel nonlinearities, inter-channel cross-phase modulation (XPM) and/or nonlinear polarization scattering. In optical communication, in which wavelength division multiplexed (WDM) channels are modulated, detecting and measuring channels with coherent detection is complicated due to impairments caused by neighboring channels. Apparatus and methods are provided which reduce the effect of impairments by performing in-line Periodic Group Delay (PGD) dispersion compensation on a WDM signal so as to enable detection of individual channels without severe degradation of system performance. Preferably the PGD dispersion compensator has within a channel a chromatic dispersion substantially similar to a DCF and between channels the group delay is substantially similar. | 12-31-2009 |
| 20110211836 | System and Method for Optimizing the Selection of Ghost Channels in Mitigating Polarization Hole Burning - A system and method for optimizing the selection of ghost channels to mitigate the effects of polarization hole burning in a node of an optical communication system including identifying an optical communication channel in the node for use as a ghost channel, identifying a first set of degrees carrying the optical communication channel within the node, identifying a second set of degrees within the first set of degrees, the second set containing the degrees with the optical communication channel being a valid channel, identifying a third set of degrees within the first set of degrees, the third set containing degrees with the optical communication channel being sufficiently powerful, and selecting a first degree to source the ghost channel from the first set of degrees based at least on the second set of degrees and the third set of degrees. | 09-01-2011 |
| 20110255870 | OPTICAL TRANSCEIVERS FOR USE IN FIBER OPTIC COMMUNICATION NETWORKS - The present disclosure provides a polarization multiplexed transceiver, including: a transmitter; a receiver; circuitry within the transmitter configured to insert pilot tones as a reference state of polarization for a polarization multiplexed signal; and circuitry within the receiver configured to de-multiplex the polarization multiplexed signal using the pilot tones. The transmitted signal is constructed in such a manner as to facilitate the division of the receiver processing between the analog and digital domains such that the implementation may be simultaneously both highly spectrally efficient and power efficient. | 10-20-2011 |
| 20100284693 | ENHANCED SMF PASSIVE OPTICAL NETWORKS USING POLARIZATION BEAMFORMING - The new invention relates to a novel high-performance Passive Optical Network (PON) upgrade architecture, based on adapting Multiple Input, Multiple Output (MIMO) beamforming techniques to polarization multiplexing. | 11-11-2010 |
| 20100329677 | Symbol Timing Recovery in Polarization Division Multiplexed Coherent Optical Transmission System - A method, apparatus and system for providing clock and data recovery in a receiver for receiving a high speed coherent polarization division multiplexed optical signal using a digital signal processing block including a spectral domain spatial combiner are provided. | 12-30-2010 |
| 20110081150 | Clock Recovery Method for Polarization Multiplexed Coherent Optical Communications - An apparatus comprising a plurality of receivers each configured to receive a plurality of polarized signals, a voltage control oscillator (VCO) coupled to the receivers and configured to control timing and sampling frequency of the polarized signals, and a signal processing component coupled to the receivers and configured to update a plurality of weighted linear factors, wherein the polarized signals and the weighted linear factors are used to obtain a combined signal, and wherein the weighted linear factors are updated using a real part or an imaginary part of the combined signal. Included is a method comprising using a linear factor to combine a plurality of polarized optical signals to provide time recovery information, and updating the linear factor using a combination of the polarized optical signals. | 04-07-2011 |
| 20100166423 | METHOD, DEVICE, AND SYSTEM FOR POLARIZATION DIVISION MULTIPLEXING AND DEMULTIPLEXING - A method, device, and system for polarization division multiplexing (PDM) and polarization division demultiplexing are provided in the field of communication and transmission. The device for polarization division demultiplexing includes a polarization controller (PC), a polarization beam splitter (PBS), a detection control module, an optoelectronic receiver | 07-01-2010 |
| 20100158521 | OPTICAL MIXER FOR COHERENT DETECTION OF POLARIZATION-MULTIPLEXED SIGNALS - An optical mixer that, in one embodiment, has a single optical hybrid optically coupled to a single polarization beam splitter. The optical hybrid mixes a polarization-multiplexed optical communication signal and a local-oscillator signal to generate four mixed signals, each corresponding to a different relative phase shift between the communication and local-oscillator signals. The polarization beam splitter separates each of the mixed signals into two polarization components, subsequent processing of which enables an optical receiver employing the optical mixer to recover the data carried by the communication signal. | 06-24-2010 |
| 20100158522 | SEED LIGHT MODULE BASED ON SINGLE LONGITUDINAL MODE OSCILLATION LIGHT SOURCE - A seed light module based on a single longitudinal mode oscillation light source is provided. The seed light module includes a multi-wavelength signal generation light source unit generating a continuous wave (CW) of different wavelengths, a multiplexer wavelength-division multiplexing the light output from the light source unit, a polarization beam splitter splitting the light of multiple wavelength components output from the multiplexer according to specific polarization components, phase modulators phase-modulating signals of a first polarization component and a second polarization component split by the polarization beam splitter onto a sine wave having a frequency and amplitude, a radio frequency (RF) signal generator generating the sine wave, a RF signal distributor distributing the generated RF signal, amplifiers amplifying the distributed RF signals, and a polarization beam combiner combining the lights phase-modulated by the respective phase modulators and providing the combined light as a seed light output. | 06-24-2010 |
| 20110217043 | ITERATIVE CARRIER-PHASE ESTIMATION AND DATA RECOVERY FOR COHERENT OPTICAL RECEIVERS - In one embodiment, a coherent optical receiver has an optical detector coupled to a digital processor. The optical detector mixes a received modulated optical signal with a local-oscillator signal to produce a digital measure of the modulated optical signal. The digital processor processes the digital measure using a primary carrier- and data-recovery (CDR) stage and one or more secondary CDR stages serially connected to one another. The processing performed in each secondary CDR stage is decision-directed and uses the symbol estimate generated by the preceding CDR stage to obtain a respective estimate of the carrier-phase offset and a respective symbol estimate. Since each subsequent CDR stage typically improves the accuracies of its estimates compared to those of the preceding CDR stage(s), the receiver has a lower bit-error rate than a receiver employing a single CDR stage. | 09-08-2011 |
| 20120308233 | RECEIVER AND CROSS PHASE MODULATION REDUCTION METHOD - A receiver includes: an extraction circuit to extract a phase fluctuation component common to phase data of two polarization components that are separated in a coherent reception of a polarization multiplexing phase modulation optical signal; and a correction circuit to correct the phase data of the two polarization components in accordance with the phase fluctuation component. | 12-06-2012 |
| 20120308234 | CLOCK RECOVERY METHOD AND CLOCK RECOVERY ARRANGEMENT FOR COHERENT POLARIZATION MULTIPLEX RECEIVERS - Component signal values are derived from component signals and fed to at least one fixed equalizer which generates equalizer output signals. The signals are fed to phase error detectors generating phase error signals. The phase error signals are combined with further phase error signals derived by further error detectors receiving signal values from further equalizers and/or the component signal values directly from sample units. | 12-06-2012 |
| 20120039607 | OPTICAL RECEIVER, OPTICAL COMMUNICATION SYSTEM USING THE SAME AND EQUALIZATION METHOD IN THE OPTICAL COMMUNICATION SYSTEM - An optical receiver according to the invention includes a polarization diversity unit receiving a polarization multiplexed optical signal obtained by multiplexing two optical signals having a same frequency band of carrier waves and polarization states orthogonal to each other, and a frequency domain equalization unit receiving signal components parallel to mutually orthogonal polarization axes from the polarization diversity unit, wherein the frequency domain equalization unit includes filters for which filter coefficients thereof are set for compensating degradation of transmission characteristics in one optical signal without polarization multiplexing by means of the frequency domain equalization. | 02-16-2012 |
| 20120039606 | LOW POWER OPTICAL TRANSCEIVER USING ORTHOGONAL POLARIZATION DETECTION TECHNIQUE - A method and apparatus for simultaneous processing of signals impressed on a horizontal polarization of a light wave and on a vertical polarization of the light wave is provided. In one embodiment, a horizontal polarization pilot tone is impressed on a data signal carried by the horizontal polarization and a vertical polarization pilot tone is impressed on a data signal carried by the vertical polarization. A receiver processes the dual-polarized light wave and converts it to an X channel signal and a Y channel signal. The X and Y channel signals are processed in separate channels to recover a phase and frequency offset between them and a local oscillator. The phase and frequency recovered and frequency de-multiplexed signals are further processed to polarization de-multiplex the data signal carried by the horizontal polarization and the data signal carried by the vertical polarization. | 02-16-2012 |
| 20110305457 | Optical Multi-Level Transmission System - Provided is an optical multilevel transmission system, comprising at least one optical multilevel transmitter for transmitting an optical multilevel signal obtained and an optical multilevel receiver for receiving the optical multilevel signal. The received optical multilevel signal has a larger noise in an angular direction than in a radial direction. The optical multilevel receiver sets, in a symbol decision of the received optical multilevel signal demodulated on the complex plane, for positions of all or some of ideal signal points, a width in the angular direction of a decision area, to which each of the ideal signal points belongs and which is measured along a circumference of a circle centered at an origin and passing through a center of the each of the ideal signal points, larger than a width in the angular direction of a decision area defined based on a Euclidean distance. | 12-15-2011 |
| 20090279891 | ALL-OPTICAL WAVELENGTH CONVERSION FOR A POLARIZATION MULTIPLEXING OPTICAL SIGNAL - An apparatus includes a first laser source for providing a first lightwave; a first optical coupler that is polarization maintaining for dividing the first lightwave into first and second optical carrier lightwaves; first and second modulators for modulating respective ones of the first and second carrier lightwaves with information; a polarization beam combiner for combining the modulated first and second carrier lightwaves which generates a polarization multiplexing optical signal; second and third lasers for providing second and third lightwaves whose wavelengths are one of both longer than that of the first lightwave and shorter than that of the first lightwave, a second optical coupler that is polarization maintaining for combining the second and third lightwaves; and a third optical coupler for combining the modulated first and second carrier lightwaves from the polarization beam combiner and the combined second and third lightwaves out of the second optical coupler for transmission over an optical medium. | 11-12-2009 |
| 20090148164 | SIGNAL EQUALIZER IN A COHERENT OPTICAL RECEIVER - A signal equalizer for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments. | 06-11-2009 |
| 20090214210 | 100 Gbit/s OFDM Optical Signal Generation - A method includes modulating lightwaves to provide first and second OFDM signal sidebands at a first polarization direction and first and second OFDM signal sidebands at a second polarization direction, and combining sidebands that are oppositely positioned and joined from the first and second OFDM signal sidebands at each polarization direction to provide a polarization multiplexing OFDM signal. | 08-27-2009 |
| 20120099864 | CHROMATIC DISPERSION VALUE CALCULATING APPARATUS, OPTICAL SIGNAL RECEIVING APPARATUS, OPTICAL SIGNAL TRANSMITTING APPARATUS, AND CHROMATIC DISPERSION VALUE CALCULATION METHOD - In order to compensate for chromatic dispersion caused by optical fiber transmission in a communication system with coherent detection using optical signals, specific frequency band signals are used to enable estimation of a chromatic dispersion value. The chromatic dispersion value calculating apparatus is provided with: a signal distributing circuit which distributes, into a plurality of signal sequences, an electrical digital signal converted from received optical signals of an optical signal transmitted by an optical signal transmitting apparatus, in which a known signal with concentrated frequency components of a plurality of specific frequencies is appended to a signal generated from a transmission data sequence; a plurality of frequency band pass filter circuits, each of which separating only each of a plurality of specific frequency components in which the known signal is included from each of the signal sequences distributed by the signal distributing circuit, and passing each of the specific frequency components therethrough; a plurality of power calculating circuits which are provided so as to correspond respectively to the plurality of frequency band pass filter circuits and which calculate power values of signals output from the corresponding frequency band pass filter circuits; a delay time calculating circuit which detects times at which power has the maximum value or times at which the power exceeds a predetermined threshold value, respectively from signal sequences of the power values output from the plurality of power calculating circuits, and which compares the detected times; and a chromatic dispersion value calculating circuit which calculates a chromatic dispersion value based on a comparison result of the times by the delay time calculating circuit. | 04-26-2012 |
| 20110097085 | OPTICAL TRANSMITTER, OPTICAL TRANSMITTER AND RECEIVER SYSTEM, OPTICAL TRANSMITTING METHOD AND OPTICAL TRANSMITTING AND RECEIVING METHOD - An optical transmitter includes: a pre-compensator calculating an electrical field of an optical signal subjected to an electronic pre-compensation with respect to an input digital signal; a parallelizer parallelizing the electrical field of the optical signal calculated by the pre-compensator; a plurality of optical modulators modulating an optical signal based on each of parallelized electrical fields of optical signals; and a time-division multiplexer time-division-multiplexing an optical signal output from the plurality of the optical modulators. | 04-28-2011 |
| 20120207476 | DATA TRANSMISSION SYSTEM AND METHOD - A method of transmitting data using electromagnetic waves, comprising the steps of providing ( | 08-16-2012 |
| 20120207474 | PLC-TYPE DEMODULATOR AND OPTICAL TRANSMISSION SYSTEM - The invention provides a PLC-type DP-QPSK demodulator that reduces connection loss between a polarization beam splitter and a 90-degree hybrid circuit and aims at reducing the manufacturing cost and an optical transmission system using the same. In an embodiment of the invention, a PLC-type DP-QPSK demodulator that receives a DP-QPSK signal includes one PLC chip having a planar lightwave circuit. Input ports and output ports of signal light are provided at an input end and at an output end of the PLC chip, respectively. Within the planar lightwave circuit, there are integrated a polarization beam splitter that splits the DP-QPSK signal into an X-polarization QPSK signal and a Y-polarization QPSK signal, and two 90-degree hybrid circuits that mix the X-polarization QPSK signal and local oscillation light and the Y-polarization QPSK signal and local oscillation light, respectively, split each QPSK signal into orthogonal components I, Q and output them. | 08-16-2012 |
| 20120207475 | RECEIVING APPARATUS, SENDING APPARATUS, SYSTEM AND METHOD FOR OPTICAL POLARIZATION DIVISION MULTIPLEXING - The present invention discloses a receiving apparatus, a sending apparatus, a system and a method for optical polarization division multiplexing. The receiving apparatus includes: an optical splitter, configured to: split a received polarization-multiplexed optical signal into two identical polarization-multiplexed optical signals, where the two polarization-multiplexed optical signals both include a first State Of Polarization (SOP) optical signal and a second SOP optical signal, and the first SOP optical signal is an optical signal when a horizontal-SOP optical signal is transmitted to the optical splitter, and the second SOP optical signal is an optical signal when a vertical-SOP optical signal is transmitted to the optical splitter; a horizontal optical signal obtaining apparatus, connected to the optical splitter and configured to separate the horizontal-SOP optical signal; and a vertical optical signal obtaining apparatus, connected to the optical splitter and configured to separate the vertical-SOP optical signal. | 08-16-2012 |
| 20120008952 | Method and Apparatus for Carrier Phase Estimation and Correction in a Coherent Optical System - An apparatus comprising a nonlinear lookup unit (NL-LUU) configured to add a phase shift to a signal sample to compensate for pattern dependent phase distortion, and one or more first phase adjustment units coupled to NL-LUU and configured to remove from the signal sample a nonlinear phase error from the NL-LUU, wherein the signal sample corresponds to a received signal polarization component of a polarization multiplexed (PM) coherent signal in a PM coherent optical system. | 01-12-2012 |
| 20120008951 | DEMODULATOR AND OPTICAL TRANSCEIVER - In a free space optical system type demodulator of a phase shift keying signal, if a half beam splitter is used as a non-polarizing optical branching unit that is used when generating beams corresponding to I and Q channels or when multiplexing an interference light, control of a power branching ratio is difficult, and it is necessary to suppress phase shifts that are different depending on a polarization state of an input state, and thereby the demodulator becomes high cost. Moreover, since directions of branched lights are different, it is difficult to suppress a skew of the demodulator. In the present invention, the non-polarizing optical branching unit that is used when generating the beams corresponding to the I and Q channels and when multiplexing the interference light is realized using polarization rotating elements and polarization separating elements. Moreover, branched beams are substantially aligned. | 01-12-2012 |
| 20120008950 | Orthogonally-Combining Interleaving Filter Multiplexer and Systems and Methods Using Same - In general, a wavelength division multiplexed (WDM) communication system simultaneously pre-filters and combines groups of wavelengths with orthogonal polarizations to provide a pre-filtered, pair-wise orthogonal aggregate WDM optical signal. In particular, an orthogonally-combining interleaving filter multiplexer provides substantially orthogonal polarizations for odd and even channel wavelengths and simultaneously pre-filters and combines the orthogonally polarized odd and even channel wavelengths using interleaver optics. The orthogonal polarizations may be provided by orientation of PM input fibers or by a polarization rotator in the orthogonally-combining interleaving filter multiplexer. | 01-12-2012 |
| 20120045208 | COHERENT RECEIVER - A coherent receiver | 02-23-2012 |
| 20120014695 | Digital Light Path Labeling System with Dual Polarization Quaternary Phase-shift Keying Modulation - A method and system for encoding and determining labels in a Dual Polarization (DP) Quaternary Phase Shift Keying (QPSK) signal is provided. A label frame, signature sequence, and data payload are combined using a complementary constant-weight code encoding (CCWC) encoder, the output of which is deinterleaved and differentially precoded to generate a polarized tributary of a DP-QPSK signal. This encoding can be duplicated for a second tributary of the DP-QPSK signal. The label can be determined using one or more polarizers and corresponding low-speed photodetectors, each applied to a copy of the DP-QPSK signal. The strongest output of the photodetectors is then used to determine the label. Alternatively, the DP-QPSK signal can be viewed as having XI, XQ, PH, and PV tributaries. These tributaries can then be translated into XI, XQ, YI, and YQ tributaries are encoded into a standard DP-QPSK signal. | 01-19-2012 |
| 20110044689 | METHOD AND SYSTEM FOR CROSS-PHASE-MODULATION NOISE REDUCED TRANSMISSION IN HYBRID NETWORKS - A system for cross-phase-modulation-noise reduced transmission in hybrid networks includes a first, second, and third set of optical transmitters. The first set of optical transmitters transmits a set of ten gigabit per second signals. The second set of optical transmitters transmits a set of forty gigabit per second signals. The third set of optical transmitters transmits a set of one hundred gigabit per second signals. On a wavelength spectrum, the set of 10 G signals is immediately adjacent to the set of 100 G signals, and the set of 100 G signals is immediately adjacent to the set of 40 G signals. The set of 10 G signals and the set of 100 G signals are not separated by a guard band. In addition, the set of 100 G signals and the set of 40 G signals are also not separated by a guard band. | 02-24-2011 |
| 20120020665 | Optical signal processor - A probe light source produces probe light having a second wavelength different from a first wavelength of signal light. To a light modulator, the probe light and signal light produced from the probe light source are supplied. The light modulator multiplexes the probe light and signal light produced from the probe light source, and supplies it to a nonlinear optical medium. Further, the light modulator modulates the probe light by an intensity change of the signal light in the nonlinear optical medium, and outputs modulated light having the second wavelength based on the data of the signal light. | 01-26-2012 |
| 20120301146 | Equivalent-Link Backward Propagation Method for Nonlinearity Compensation in Fiber Transmission Systems - A method includes transmitting an optical signal over an optic link in a communication system, the optical link including an optical fiber and optical amplifier; coupling a coherent receiver in the communication system to the optic link for receiving the optical signal; and processing an output from the coherent receiver with digital signal processing DSP in the communication system, the DSP compensating for impairments of the optical signal due to the fiber optic link with an equivalent-link back-propagation. | 11-29-2012 |
| 20120027410 | METHOD, DEVICE AND SYSTEM FOR GENERATING AND RECEIVING A PHASE POLARIZATION MODULATED SIGNAL - In the field of communications transmission, a method, a device, and a system for generating and receiving a phase polarization modulated signal are disclosed. The device for generating the phase polarization modulated signal includes: a Laser Diode (LD), a time division demultiplexer, a phase precoding module, a phase modulating module, a polarization precoding module and a polarization modulating module. The device for receiving the phase polarization modulated signal includes: an optical splitter, a polarizer, a phase demodulating and receiving unit, a Polarization Beam Splitter (PBS), a balanced receiver, a power divider, an exclusive OR, a delayer and a data interface processing unit. Therefore, problems in the prior art that a Differential Quadrature Phase Shift Keying (DQPSK) signal cannot bear and transmit information at a higher rate and that non-linear effect is strong during transmission are solved, and transmission performance of an optical signal is improved. | 02-02-2012 |
| 20120155875 | OPTICAL RECEIVER - Disclosed is an optical receiver including: a polarization splitter splitting two polarization components perpendicular to each other from an optical signal to output a first polarization signal and a second polarization signal; a first optical delay splitter and a second optical delay splitter branching each polarization signal to output two branch signals, respectively; a first optical hybrid and a second optical hybrid each outputting four interference signals in which a phase shift increases by each 90° by using the two branch signals; and four photo detectors each outputting a differential signal between two interference signals in which the phase shift is 180° . | 06-21-2012 |
| 20120155876 | SEED LIGHT MODULE FOR WAVELENGTH DIVISION MULTIPLEXING-PASSIVE OPTICAL NETWORK AND METHOD FOR DRIVING THE SAME - A seed light module for a WDM-PON system is provided. The seed light module includes a reflector configured to reflect a part of seed light that is generated from a light source generator, and an optical attenuator configured to attenuate the intensity of the reflected seed light and provide the attenuated seed light, which corresponds to a signal generated by attenuating the intensity of the reflected seed light, to the light source generator. | 06-21-2012 |
| 20120251112 | METHOD AND SYSTEM FOR COHERENT EQUALIZATION OF CHROMATIC DISPERSION OF OPTICAL SIGNALS IN A FIBER - Method and system for optimally equalizing distortion of an optical data channel carrying coherent optical signals with a given analog bandwidth B. A receiving end with IQ paths receives signals and a balanced detector detects signals in each path. The bandwidth of the detected signals is reduced by a factor of N by filtering the output of each path using an AAF with a cutoff frequency optimized to the analog bandwidth 2B/N of each path, where the AAF has deterministic attributes and introducing Known ISI. The signal is sampled at the AAF output by an ADC, at a sampling rate of 2B/N. The samples of each path are post-processed by a digital processor operating at a data rate of 2B/N, where post-processing represents the compensation of the distortion and the input data stream is reconstructed by optimally decoding the output of the processor using a decoder, which compensates the ISI. | 10-04-2012 |
| 20100196009 | POLARIZATION INDEPENDENT FREQUENCY DOMAIN EQUALIZATION (FDE) FOR CHROMATIC DISPERSION (CD) COMPENSATION IN POLMUX COHERENT SYSTEMS - A method for the polarization independent frequency domain equalization (FDE) chromatic dispersion compensation on polarization multiplexing (POLMUX) coherent systems. Operationally, time domain signals are converted to frequency domain signals such that time domain convolution can be done as simple multiplications in the frequency domain. These frequency domain signals then converted back to time domain for subsequent use. The input signal size and FFT size are advantageously designed so that the output signals can be continuous with some overlap between two successive frames. | 08-05-2010 |
| 20100196008 | METHODS AND APPARATUS FOR RECOVERING FIRST AND SECOND TRANSMITTED OPTICAL WAVES FROM A POLARIZATION MULTIPLEXED OPTICAL WAVE - First and second transmitted optical waves having orthogonal polarization states are combined in a polarization multiplexed optical wave. At an optical receiver, an electrical field of the polarization multiplexed optical wave is measured. A plurality of polarization states of the polarization multiplexed optical wave is determined from the measured electrical field. From the plurality of polarization states, a transform that aligns the orthogonal polarization states of the first and second transmitted optical waves with respect to principal axes of the optical receiver is estimated. The first and second transmitted optical waves are recovered by applying the transform to one of i) the polarization multiplexed optical wave and ii) the measured electrical field of the polarization multiplexed optical wave. | 08-05-2010 |
| 20120121264 | APPARATUS AND METHOD FOR TRANSMITTING LIGHT, AND APPARATUS AND METHOD FOR RECEIVING LIGHT - An optical transmitting apparatus optically modulates a transmitting signal to transmit the signal to an optical receiving apparatus using a phase of two optical carriers having each wavelength, and an optical receiving apparatus demodulates an optical signal having a modulated phase with intensity modulation to detect a transmitting signal. | 05-17-2012 |
| 20120315043 | TRANSMISSION METHOD, RECEPTION METHOD, TRANSMITTER APPARATUS, AND RECEIVER DEVICE - A polarization state of a transmission signal can be changed at a high speed based on a symbol-rate By switching a first switch, a second switch, and a third switch with time, one of an X-polarized wave_I-signal as a Y-polarized wave_I-signal, a signal caused by performing logical inversion for an X-polarized wave_I-signal, an X-polarized wave_Q-signal and a signal caused by logical inversion for an X-polarized wave_Q-signal is input to a second modulator. Further, by switching the first switch, the second switch and the third switch with time, the second modulator is input one of the X-polarized wave_I-signal as the Y-polarized wave_Q-signal, the X-polarized wave_I-signal, the signal caused by performing logical inversion for the X-polarized wave_I-signal, the X-polarized wave_Q-signal and the signal caused by performing logical inversion for the X-polarized wave_Q-signal. Thereby, a polarization state of a transmission signal can be changed at high speed based on a symbol-rate speed. | 12-13-2012 |
| 20120134676 | Polarization-Multiplexed Optical Transmission System, Polarization-Multiplexed Optical Transmitter, and Polarization-Multiplexed Optical Receiver - There is a need to prevent two receivers from converging on a state of receiving the same polarization state, fast start receivers, and ensure highly reliable operations. A polarization-multiplexed transmitter previously applies frequency shifts of frequencies +Δf and −Δf to X-polarization and Y-polarization digital information signals to be transmitted. Optical field modulators modulate and polarization-multiplex the signals. As a result, a frequency difference of 2Δf is supplied to X-polarization and Y-polarization components. A polarization diversity coherent optical receiver | 05-31-2012 |
| 20120251110 | COMPUTATIONALLY-EFFICIENT EQUALIZATION IN POLMUX OFDM TRANSMISSION WITH DIRECT-DETECTION VIA JOINT TRANSMITTER AND RECEIVER PROCESSING - A method for joint transmitter and receiver processing for computationally efficient equalization in polarization multiplexed (POLMUX) optical orthogonal frequency division multiplexed (OFDM) transmission with direct detection. | 10-04-2012 |
| 20120177372 | Apparatus And Method For Generating Interleaved Return-To-Zero (IRZ) Polarization-Division Multiplexed (PDM) Signals - Return To Zero (RZ) shaping is performed for a first I/Q modulator whose output corresponds to a first polarization component using a first two digital-to-analog convertors (DACs), each of which is sampled at approximately twice a modulation symbol rate or more and has an output with a first interleaving order that interleaves one of a first pair of intended drive signal patterns and zeros. RZ shaping is also performed for a second I/Q modulator whose output corresponds to a second polarization component using a second two DACs, each sampled at approximately twice the modulation symbol rate or more and having a second interleaving order that interleaves zeros and one of a second pair of intended drive signal patterns, the second interleaving order opposite the first interleaving order. The first polarization and the second polarization may be combined, thereby forming an Interleaved Return To Zero (IRZ) Polarization Division Multiplexed (PDM) signal. | 07-12-2012 |
| 20120257896 | CODED MULTIDIMENSIONAL PULSE AMPLITUDE MODULATION FOR ULTRA-HIGH-SPEED OPTICAL TRANSPORT - Systems and methods are disclosed to provide optical communication by using subcarriers as individual bases functions, obtaining signal constellation points of an N-dimensional pulse amplitude modulation (ND-PAM) constellation diagram as an N-dimensional Cartesian product of a one-dimensional PAM; and transmitting the N-dimensional signal constellation point over all N orthogonal subcarriers serving as individual bases functions. | 10-11-2012 |
| 20090060508 | Polarization multiplexing and transmitting apparatus - A polarization multiplexing and transmitting apparatus generates polarization multiplexed light by multiplexing modulated signal components that having varying intensities and are in polarization states orthogonal to each other. The polarization multiplexing and transmitting apparatus includes a converting unit that converts light generated by a light source into signal components having a varying intensity synchronized with a clock signal input thereto and a varying intensity inversely synchronized with the clock signal, respectively; a modulating unit that modulates the signal components, respectively; and a polarization adjusting unit that orthogonalizes polarization states of the signal components. | 03-05-2009 |
| 20120263467 | Polmux-OFDM-DD Transmitter and Receiver for Reduced Complexity and Overhead in Optical Access/Metro Transmission - An optical communication system includes a polarization multiplexed orthogonal frequency-division multiplexing POLMUX-OFDM transmitter for generating a POLMUX-OFDM double sideband signal, an optical processing path for processing the double sideband signal from the transmitter; an analog-to-digital convert ADC-OFDM receiver coupled to the optical processing path for receiving the double sideband signal processed by the optical path; and a block-diagonal multiple-input multiple-output MIMO equalizer responsive to the receiver for enabling correct operation for a completely random incoming signal polarization state without adaptive polarization control at said receiver, which enables complexity. | 10-18-2012 |
| 20120263468 | Generation of Optical Quadrature Duobinary Format Using Optical Delay - An optical method for generating an optical quadrature duobinary QDB signal includes receiving a quadrature phase-shift-keying QPSK signal, and adding a delay to the received quadrature phase-shift-keying QPSK signal to generate an optical quadrature duobinary signal. | 10-18-2012 |
| 20120082457 | K-Means Clustered Polyphase Filtering for Sample Rate Conversion in Coherent Polarization Multiplexing Fiber Optic Systems - A method for clustered polyphase filtering input data converted from an optical signal converting input data from a serial form into a parallel form, permutating data symbols from the input data to form K clusters, passing the permutated data to an adder and multiplier for each cluster; and adding output of all K multipliers together to form an output. | 04-05-2012 |
| 20120263465 | OPTICAL TRANSMISSION SYSTEM AND OPTICAL TRANSMISSION METHOD - An optical transmission system includes: a two-lightwave generator for generating optical signals having wavelengths λ | 10-18-2012 |
| 20120263464 | Adaptive Cross-Polarization Modulation Cancellers for Coherent Optical Communication Systems - For coherent fiber optic communications, the nonlinear XPolM impairment is the most important issue to realize over-100 Gbps high-speed transmissions. A method provides a way to cancel time-varying XPolM crosstalk by introducing multi-stage adaptive mechanism. In the method, a low-complexity adaptive filtering based on recursive least-squares (RLS) first tracks the time-varying crosstalk along with the per-survivor trellis-state decoding. The estimated channel and the decoded data are then used to calculate the empirical covariance, which is in turn exploited to obtain more accurate channel estimates by means of optimal-weighted least-squares. This is performed with a low-complexity processing over frequency domain with fast Fourier transform. The performance is significantly improved with turbo principle decoding, more specifically, iterative decoding and iterative estimation over a block. | 10-18-2012 |
| 20120257895 | FOUR-DIMENSIONAL OPTICAL MULTIBAND-OFDM FOR BEYOND 1.4TB/S SERIAL OPTICAL TRANSMISSION - Systems and methods are disclosed to perform four-dimensional optical multiband OFDM communication by organizing an N-dimensional (ND) signal constellation points as a signal matrix; performing 2D-inverse FFT and 2D-FFT to perform modulation and demodulation, respectively; and applying both orthogonal polarizations in the OFDM communication to deal with chromatic dispersion, PMD and PDL effects, and multidimensional signal constellation to improve optical signal-to-noise ratio (OSNR) sensitivity. | 10-11-2012 |
| 20120093510 | CORRELATION -CONTROL QPSK TRANSMITTER - An optical transmitter utilizing a multi-level data modulator to produce a PDM-QPSK signal, a one-bit delay interferometer configured to correlate the multi-level data modulated signal and an optical filter configured to combine the correlated multi-level data modulated signal with one or more neighboring signals prior to transmitting over one of a plurality of optical channels. The PDM-QPSK correlated signal is configured to reduce the signal spectrum thereby increasing spectral efficiency of the transmitted signal. | 04-19-2012 |
| 20120263466 | MULTIDIMENSIONAL HYBRID MODULATIONS FOR ULTRA-HIGH-SPEED OPTICAL TRANSPORT - Systems and methods are disclosed with a spatial-domain-based multi-dimensional coded-modulation scheme that improves dramatically OSNR sensitivity and tolerance to fiber nonlinearities by using D-dimensional signal constellations, where D=2(2+M)N. The factor 2 originates from two polarizations, 2+M electrical basis functions are selected (2 in-phase/quadrature channels and M pulse-position like basis functions), and N represents the number of orbital angular momentum (OAM) states used in FMFs/MMFs. For single mode fiber applications N is 1. | 10-18-2012 |
| 20110038631 | COHERENT RECEIVER HAVING AN INTERLEAVE-CHIRPED ARRAYED WAVEGUIDE GRATING - An optical coherent detector that employs an interleave-chirped arrayed waveguide grating (AWG). The AWG has a periodic chirp pattern that enables the AWG to function as an optical 90-degree hybrid. If the AWG is implemented using a birefringent material, then the AWG can also function as a polarization demultiplexer. In one embodiment, the AWG is designed to simultaneously function as a wavelength demultiplexer, a polarization demultiplexer for each wavelength-division-multiplexed (WDM) signal component, and a 90-degree hybrid for each polarization-division-multiplexed component of each WDM signal component. | 02-17-2011 |
| 20120269512 | TRANSPORT OF MULTIPLE ASYNCHRONOUS DATA STREAMS USING HIGHER ORDER MODULATION - Aspects of the invention provide transmitters and receivers for managing multiple optical signals. High order modulation, such as phase and/or amplitude modulation, is used to achieve multiple bits per symbol by transporting multiple asynchronous data streams in an optical transport system. One or more supplemental multiplexing techniques such as time division multiplexing, polarization multiplexing and sub-carrier multiplexing may be used in conjunction with the high order modulation processing. This may be done in various combinations to realize a highly spectrally efficient multi-data stream transport mechanism. The system receives a number of asynchronous signals which are unframed and synchronized, and then reframed and tagged prior to the high order modulation. Differential encoding may also be performed. Upon reception of the multiplexed optical signal, the receiver circuitry may employ either direct detection without a local oscillator or coherent detection with a local oscillator. | 10-25-2012 |
| 20120269513 | OPTICAL RECEPTION DEVICE AND OPTICAL RECEPTION CONTROL METHOD - An optical reception device ( | 10-25-2012 |
| 20120321311 | Coherent Interleaved Polarization-Multiplexing Optical Communications with Single IQ Modulator - An inventive method for coherent interleaved polarization-multiplexing PolMux optical communications with a single IQ modulator includes modulating a light source to generate a 50% return-to-zero RZ signal pulse at a frequency Rs, driving a single IQ modulator with inphase I and quadrature phase Q data at a bit rate of sais Rs to introduce phase modulation on said 50% RZ signal pulse to produce a QPSK pulse signal with all symbols being in a same polarization state without any time overlapping; and polarization modulating said QPSK signal to alternatively convert said QPSK signal into two orthogonal polarizations states enabling an interleaving PolMux signal with a symbol rate of Rs/2. | 12-20-2012 |
| 20110229137 | Tunable Receiver - Embodiments for optical communication are provided in which tunable receiver selects and demodulates a first channel of a WDM signal. An example receiver includes a tunable local oscillator for generating a local oscillator signal approximately centered at a first channel wavelength. An optical hybrid of the receiver receives at a first input a wavelength-division-multiplexed (WDM) signal with a M-ary modulation scheme, wherein M is an integer greater than 2, and at a second input the local oscillator signal. A plurality of detectors detect in-phase and quadrature components of the first channel wavelength output of the optical hybrid, which are digitizing by a plurality of analog-to-digital converters. A digital signal processor processes the digitized in-phase and quadrature components in order to recover data carried by the first channel of the WDM signal. | 09-22-2011 |
| 20120275791 | METHOD AND APPARATUS FOR IMPLEMENTING PDM-BPSK MODULATION AND QPSK MODULATION IN COMPATIBLE MANNER - A method for implementing Polarization Division Multiplexing Binary Phase Shift Keying (PDM-BPSK) modulation and Quadrature Phase Shift Keying (QPSK) modulation in a compatible manner includes: dividing a direct current (DC) light into a first channel of light and a second channel of light with the same power; separately performing optoelectrical modulation on the first channel of light and the second channel of light and correspondingly outputting a first optical signal and a second optical signal in a Binary Phase Shift Keying (BPSK) format; performing polarization state control on the first optical signal; performing a phase shift on the first optical signal or the second optical signal; and performing optical signal combination with the polarization state preserved on the first optical signal and the second optical signal after the polarization state control and the phase shift, and outputting a PDM-BPSK modulation optical signal or a QPSK modulation optical signal. | 11-01-2012 |
| 20110274430 | Optical transmission system - An optical transmission system, where in an optical transmitter a detection bit having a specific pattern set according to the number of bits to be transmitted within one symbol time, is imparted with respect to a transmission signal in which transmission information has been encoded according to a preset format, and an optical signal generated by modulating light according to the transmission signal is transmitted to a transmission line. In an optical receiver, logic inversion or bit swap of received data is detected and compensated by using the detection bit included in the received signal, a decoding process of the compensated received signal is executed. As a result, when an optical signal capable of transmitting multi-bit information within one symbol time is transferred, it is possible to realize excellent transmission characteristics, by reliably compensating an error in received data caused by the modulation format or the multiplex system of the optical signal. | 11-10-2011 |
| 20100086303 | HIGH SPEED POLMUX-OFDM USING DUAL-POLMUX CARRIERS AND DIRECT DETECTION - A polarization multiplexing, orthogonal frequency division multiplexing (POMUX) transmission system utilizing direct detection. | 04-08-2010 |
| 20120251111 | OPTOELECTRONIC WAVELENGTH CONVERTER FOR POLARIZATION MULTIPLEXED OPTICAL SIGNALS - A wavelength converter that operates on an optical signal having single or multiplexed polarizations and which exhibits any modulation format. | 10-04-2012 |
| 20130121698 | Systems And Methods For Processing Space-Multiplexed Optical Signals - In one embodiment, an optical system for processing space-multiplexed optical signals includes an input fiber that propagates multiple spatially-separated optical signals, a photonic signal processor that receives the multiple spatially-separated optical signals and simultaneously processes those signals, and an output fiber that receives at least one of the processed signals. | 05-16-2013 |
| 20130136449 | COMMUNICATION THROUGH MULTIPLEXED ONE-DIMENSIONAL OPTICAL SIGNALS - An example apparatus comprises an optical transmitter which includes a first processor and at least two optical modulators. The first processor is configured to generate a first electronic representation for each of at least two optical signals for carrying payload data modulated according to a one-dimensional (1-D) modulation format, and to induce on respective ones of the first electronic representations an amount of dispersion that depends on a power-weighted accumulated dispersion (AD | 05-30-2013 |
| 20130136451 | OPTICAL TRANSFER SYSTEM, OPTICAL TRANSMISSION DEVICE, AND OPTICAL RECEPTION DEVICE - In an optical transfer system, an optical transmission unit generates an optical signal in which respective polarization components are alternately present on a time axis, a time period during which the respective polarization components are simultaneously present on the time axis is substantially zero, and a symbol repetition cycle of optical signals of the respective polarization components becomes Ts, an optical reception unit causes an interference between local oscillation light and a received optical signal and converts an interfered optical signal to an electric signal, and a received electric-signal processing unit performs analog-digital conversion of an electric signal, elimination of a delay difference of Ts/2 between the respective polarized signal components, and adaptive equalization of a distortion other than the delay difference. | 05-30-2013 |
| 20130136450 | SIGNAL EQUALIZER IN A COHERENT OPTICAL RECEIVER - A signal equaliser for compensating impairments of an optical signal received through a link of a high speed optical communications network. At least one set of compensation vectors are computed for compensating at least two distinct types of impairments. A frequency domain processor is coupled to receive respective raw multi-bit in-phase (I) and quadrature (Q) sample streams of each received polarization of the optical signal. The frequency domain processor operates to digitally process the multi-bit sample streams, using the compensation vectors, to generate multi-bit estimates of symbols modulated onto each transmitted polarization of the optical signal. The frequency domain processor exhibits respective different responses to each one of the at least two distinct types of impairments. | 05-30-2013 |
| 20130148965 | MULTIPROTOCOL TRANSPORT USING POLARIZATION DIVISION MULTIPLEXING - Using polarization modulation techniques to simultaneously transmit two different data streams (formatted according to two different protocols) over a single optical wavelength. A first data stream that is encapsulated for transport using a first transport protocol, and a second data stream that is encapsulated for transport using a second transport protocol are received. The first data stream is modulated on a wavelength with a first polarization mode of a polarization division modulation scheme to produce a first modulated data stream and the second data stream is modulated on the wavelength with a second polarization mode of the polarization division multiplex transmission scheme to produce a second modulated data stream having the second polarization mode. The second polarization mode is orthogonal to the first polarization mode. The first and second data streams are combined onto a single wavelength for transmission over a single optical fiber using a polarization beam combiner. | 06-13-2013 |
| 20130148966 | OPTICAL MODULE HAVING A PLURALITY OF OPTICAL SOURCES - An optical module that outputs a wavelength multiplexed optical signal is disclosed. The optical module provides at least first to third optical source, a wavelength multiplexer, a polarization rotator, and a polarization multiplexer. The optical sources each outputting first to third optical signals with a wavelength different from others. The wavelength multiplexer multiplexes the first optical signal with the third optical signal. The polarization rotator rotates the polarization vector of one of the multiplexed first and third optical signals and the second signal by substantially 90°. The polarization multiplexer multiplexes the polarization rotated optical signal with the second optical signal. | 06-13-2013 |
| 20130148967 | DISTORTION COMPENSATOR, OPTICAL RECEIVER, DISTORTION COMPENSATOR AND OPTICAL RECEIVER CONTROLLING METHODS, AND OPTICAL TRANSMISSION SYSTEM - A distortion compensator, an optical receiver and a transmission system including an operation selectively compensating for linear waveform distortion exerted on an optical signal via a plurality of distortion compensators and compensating for nonlinear waveform distortion exerted on the optical signal using nonlinear distortion compensators. | 06-13-2013 |
