Patent application number | Description | Published |
20080199189 | COLORLESS OPTICAL DEMODULATOR FOR DIFFERENTIAL QUADRATURE PHASE SHIFT KEYING DWDM SYSTEMS - A colorless optical DQPSK demodulator and system operating over multiple, equally-spaced DWDM channels with fixed optical delays—capable of demodulating DQPSK within signals within DWDM communications wave bands on ITU grids using delay interferometers having fixed free spectral range at 20 GHz or 25 GHz. | 08-21-2008 |
20080240736 | Inter-Symbol Interference-Suppressed Colorless DPSK Demodulation - An optical device includes an interferometer for a received optical differential phase shift keying DPSK signal, and an equalizer integrated with the interferometer in a manner for reducing from optical filtering effects an interference by signal bits of the DPSK signal with signal bits of a contiguous DPSK signal. The interferometer is a Michelson delay interferometer type, but can also be a Mach-Zehnder delay interferometer type on fiber, waveguide or other optical structure. The equalizer is a Fabry-Perot type equalizer, but can be a ring resonator type or a fiber based equalizer. | 10-02-2008 |
20080253768 | High Bit Rate Packet Generation with High Spectral Efficiency in an Optical Network - Optical packets are generated by generating a first optical beam with a first wavelength and a second optical beam with a second optical beam. The first optical beam is modulated with a payload signal and then filtered to reduce the bandwidth of the signal. The second optical beam is modulated with a label signal. The filtered modulated first optical beam and modulated second optical beam are combined to generate a dual-wavelength optical beam. | 10-16-2008 |
20080260383 | CENTRALIZED RESOURCE MANAGEMENT IN WAVELENGTH SELECTIVE SWITCH BASED WAVELENGTH CROSS CONNECT SYSTEMS - A Centralized Resource Management (CRM) system that supports the sharing of all the transponders in a WXC node, i.e., any spare transponder can be reconfigured to accommodate any drop channel, regardless of wavelength or input port. Consequently, network restoration in case of network failures is supported as well as the ability to reconfigure as a result of dynamic traffic requirements in the network. CRM advantageously is applied to conventional WXC node as well as WSS-based WXC nodes in the WDM networks. Three CTM schemes which manage the transponders in the WSS-based WXC node are described along with reconfiguration algorithms for an optical switchless CRM solution. | 10-23-2008 |
20080266014 | ON-OFF KEYING - 7-PHASE SHIFT KEYING MODULATION SYSTEM AND METHOD FOR FIBER COMMUNICATION - A modulation system includes a modulator configured to employ a modulation mechanism on data. The mechanism includes a signal constellation configured to map sub-carriers which include a signal to be modulated. The signal constellation has a plurality of points asymmetrically disposed on a circle about an origin and a point at the origin wherein a number of sub-carriers becomes variable over different symbol intervals. Corresponding demodulators and corresponding methods are also disclosed. | 10-30-2008 |
20080267630 | ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS (OFDMA) BASED PASSIVE OPTICAL NETWORK (PON) ARCHITECTURE AND ITS EXTENSION TO LONG DISTANCE - A passive optical network (PON) device, system and method include an optical line terminal (OLT) receiver configured to receive multiple signals at different wavelengths simultaneously and enable multiple transmitters to operate at the same time during one upstream time slot. The optical line terminal employs Orthogonal Frequency Division Multiple Access (OFDMA) to transparently support a plurality of applications and enable dynamic bandwidth allocation among these applications where the bandwidth is allocated in two dimensional frequency and time space. | 10-30-2008 |
20080279556 | Wavelength Division Multiplexed Passive Optical Network - Data is transmitted between a central office and customer premises by a wavelength division multiplex passive optical network. Two laser beams with separate wavelengths are transmitted from the central office to an optical network unit in the customer premises. Both laser beams carry downstream data. One laser beam is intensity modulated by on/off keying. The other laser beam is phase modulated by differential phase shift keying, which maintains a constant optical intensity. The first laser beam is received by a first optical receiver, which demodulates the first downstream data. The second laser beam is split in two. One laser beam is sent to a second optical receiver, which demodulates the second downstream data. The other laser beam is sent to a reflective semiconductor amplifier, which modulates the beam with upstream data and transmits the beam back to a receiver in the central optical system. | 11-13-2008 |
20080294968 | Ultra High-Speed Optical Transmission Based on LDPC-Coded Modulation and Coherent Detection for All-Optical Network - An optical communication system includes a bit-interleaved coded modulation (BICM) coder; and a low-density parity-check (LDPC) coder coupled to the BICM coder to generate codes used as component codes and in combination with a coherent detector. | 11-27-2008 |
20090016739 | PATTERN EFFECT REDUCTION OF OPTICAL SIGNALS - A passive optical equalizer and a predistortion technique are employed to reduce pattern effect in optical signals which result from narrow filtering. | 01-15-2009 |
20090052907 | WAVELENGTH TRANSMISSION SYSTEM AND METHOD USING 3-DIMENSIONAL LDPC-CODED MODULATION - A transmitter and method include a LDPC encoder configured to encode source data, and a mapper configured to generate three coordinates in accordance with a | 02-26-2009 |
20090059351 | DEMODULATOR SYSTEM AND METHOD USING MULTILEVEL DIFFERENTIAL PHASE SHIFT KEYING - A demodulator and demodulation method includes an optical coupler configured to receive an input signal. The optical coupler couples the signal to an even number of branches. Each branch including at least one interferometer configured to split, combine and interfere with an optical signal from one of within the branch or from another branch. A common optical delay is disposed on one of every two branches between the optical coupler and the interferometer of the branch. | 03-05-2009 |
20090092391 | METHOD AND SYSTEM FOR POWER STABILITY CONTROL IN WAVELENGTH DIVISION MULTIPLEXING NETWORKS - Methods and systems for controlling power fluctuations in a network including a plurality of nodes are disclosed. A node in the network may be configured to modify power levels in accordance with either an active state or an inactive state. The node may transition to an inactive state in response to a power change that exceeds a power change threshold. The role of the node in controlling the power fluctuation in the network is reduced in the inactive state. | 04-09-2009 |
20090092392 | VIRTUAL I/Q MULTIPLEXING IN OPTICAL CODE DIVISION FOR SECURE LOCAL AREA OFDM - A system and method for virtual I/Q multiplexing in optical code division for secure local area OFDM includes encoding a wide spectrum signal, which includes a plurality of spectral bins, to provide a complementary spectral coding over at least two channels. The complementary spectral codings are intensity modulated with opposite polarity for each channel. An M-ary Orthogonal Frequency Division Multiplexing (OFDM) signal is modulated using the complementary spectral codings of opposite polarity with separate complementary spectral encoded (CSE) optical codes to provide a virtual in-phase (I) and quadrature (Q) (I/Q) multiplexing for the OFDM signal. | 04-09-2009 |
20090177945 | POLARIZATION MODE DISPERSION COMPENSATION USING BCJR EQUALIZER AND ITERATIVE LDPC DECODING - A turbo equalizer includes a Bahl-Cocke-Jelinek-Raviv (BCJR) equalizer configured to receive a transmitted signal and partially cancel inter-symbol interference (ISI) due to polarization-mode dispersion (PMD). A low-density parity check (LDPC) decoder is coupled to the BCJR equalizer to receive channel bit reliabilities therefrom. The LDPC decoder iteratively provides extrinsic soft information feedback to the BCJR equalizer to compensate for PMD. | 07-09-2009 |
20090202243 | Direct Detection For Receiving Polarization Multiplexing Signals - There is provided a method for detecting optical signals comprising employing a photo diode to both directly detect a received optical signal and convert it into an electrical signal for recovery of data bit stream information in the received optical signal, the received optical signal being derived from a separation of two polarization multiplexed optical signals that were combined before being received. | 08-13-2009 |
20090245810 | Dynamic Signal Equalization in Optical Transmission Systems - In an optical transmission system, data is transmitted via an optical beam modulated with an arbitrary waveform. The optical beam is transmitted through at least one optical element. Transmission through at least one optical element degrades the signal quality of the initial optical beam. The signal characteristics of at least one optical beam at the output of least one optical element are used as feedback to shape the arbitrary waveform to improve signal characteristics. An arbitrary waveform may be used to compensate signal degradation caused by a multiplexer/demultiplexer in a wavelength division multiplex system. | 10-01-2009 |
20090251345 | PHOTONIC FILTER BANK FOR HIGH-SPEED ANALOG-TO-DIGITAL CONVERSION - An analog to digital converter (ADC) structure and method includes a photonic filter bank having at least two filters. The at least two filters are configured to create a corresponding spectral tributary from an input signal at a target rate, and the at least two filters are configured to exhibit orthogonality properties between respective tributaries. An optical/electrical (O/E) converter is coupled to each of the at least two filters in a respective spectral tributary to convert an optical input to an electrical output. An analog to digital converter (ADC) is coupled to each of the O/E converters in a respective spectral tributary to sample the electrical output at a fraction of a target rate and to convert a sampled analog electrical output into a digital signal. A synthesis filter is coupled to each of the ADCs in a respective spectral tributary to reconstruct the input signal digitally at the target rate. | 10-08-2009 |
20090259912 | LDPC CODES AND STOCHASTIC DECODING FOR OPTICAL TRANSMISSION - A method for error correction and a decoder using low density parity check (LDPC) codes includes initializing extrinsic probability information between variable nodes and check nodes in a bipartite graph including generating a Bernoulli sequence according to a probability of a bit having a value one. Parity checking is performed in accordance with a parity check equation. If the parity check equation is not satisfied, then extrinsic information is updated in check nodes from variable nodes using a parity node update logic circuit in a first half iteration, extrinsic information is updated in variable nodes from check nodes using a variable node update logic circuit in a second half iteration, and the variable nodes are updated with a probability based upon the extrinsic information passed between check nodes and variable nodes wherein the probability represents a likelihood that an ith bit is a one. Information bits are passed when the parity check equation is satisfied or a predetermined number of iterations has been reached. | 10-15-2009 |
20090274460 | DIFFERENTIAL DELAY RECEIVER USING CROSS-POLARIZATION INTERFEROMETER FOR POLMUX-DPSK SYSTEM - A differential delay detection system and method includes an optical splitter to split an incoming optical signal between a first path and a second path. The first path includes a cross-polarization interferometer configured to separately generate polarization independent outputs using split paths and to generate cross-polarization interference outputs, and a polarization demultiplexer configured to combine the polarization independent outputs and the cross-polarization interference outputs from the cross-polarization interferometer with updated coefficients received from the second path to remove the cross-polarization mixed signals, The second path includes a training signal receiver configured to compute the updated coefficients and output the updated coefficients to the polarization demultiplexer. | 11-05-2009 |
20090285577 | Optical Frontend for Integration of Optical and Wireless Networks - Data is transmitted by radio over fiber in a wavelength division multiplex optical transmission system. Data is transmitted over a single optical channel by directly modulating a single wavelength laser with a baseband data signal. Multiple single wavelength laser beams are multiplexed into a single multi-wavelength laser beam. All of the single optical channels are up-converted to RF frequencies by modulating the intensity of the multi-wavelength laser beam with an RF carrier. | 11-19-2009 |
20100028002 | PASSIVE OPTICAL NETWORK SYSTEM EMPLOYING SUB-CARRIER MULTIPLEXING AND ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS MODULATION SCHEMES - Implementations of the present principles include methods, systems and apparatuses for transmitting data through a sub-carrier multiplexing and orthogonal frequency-division multiple access passive optical network. In accordance with aspects of the present principles, a plurality of optical network units are assigned electrical carrier frequency bandwidths that are narrower than a system capacity bandwidth. Modulation of optical waves transmitted between an optical line terminal and each optical network unit is conducted on different orthogonal sub-carrier frequencies within the assigned bandwidths such that sampling of said orthogonal sub-carrier frequencies is limited to the assigned electrical carrier frequency bandwidths. The waves are thereafter received and demodulated for the extraction of data. | 02-04-2010 |
20100054737 | Parallel Optical Polarization Tracking - A system to communicate optical data signals in parallel includes an optical splitter to split the data signals into two polarization multiplexed (PM) signals; and two reception channels coupled to the optical splitter, where each reception channel tracks and isolates a PM signal independently. | 03-04-2010 |
20100061470 | SLICEABLE ROUTER WITH PACKET OVER OPTICAL OFDM TRANSMISSION - A sliceable router includes a forwarding engine; a routing engine coupled to the forwarding engine; multiple virtual packet interfaces coupled to the forwarding engine, wherein the interfaces shares an optical orthogonal frequency-division multiple accesses (OFDMA)-based programmable transceiver for interface virtualization; and one or more physical packet interfaces coupled to the forwarding engine. | 03-11-2010 |
20100086303 | HIGH SPEED POLMUX-OFDM USING DUAL-POLMUX CARRIERS AND DIRECT DETECTION - A polarization multiplexing, orthogonal frequency division multiplexing (POMUX) transmission system utilizing direct detection. | 04-08-2010 |
20100088571 | HIGH SPEED LDPC DECODING - An optical probability-domain LDPC decoder suitable for implementation at 100 Gb/s and above provides large coding gains when based on large-girth LDPC codes. A basic building block, the probabilities multiplier circuit, used to implement both check node and probability node update circuits can be implemented using Mach-Zehnder delay interferometer. | 04-08-2010 |
20100142952 | ADAPTIVE CROSSING FREQUENCY DOMAIN EQUALIZATION (FDE) IN DIGITAL POLMUX COHERENT SYSTEMS - A method for the polarization independent frequency domain equalization (FDE) on polarization multiplexing (POLMUX) coherent systems employing an adaptive crossing FDE which advantageously produces CD compensation, PMD compensation and PolDeMux within one functional block of a digital signal processor (DSP). | 06-10-2010 |
20100211849 | MULTI-DIMENSIONAL LDPC CODED MODULATION FOR HIGH-SPEED OPTICAL TRANSMISSION SYSTEMS - Arbitrarily high data transmission rates may be achieved by the use of N-dimensional, LDPC-coded modulation. N orthonormal basis functions are employed using coherent reception, resulting in a proportional increase in transmission rate with only a modest increase in bit-error ratio. | 08-19-2010 |
20100215368 | SINGLE WAVELENGTH SOURCE-FREE OFDMA-PON COMMUNICATION SYSTEMS AND METHODS - Methods and systems for processing communication signals in an Orthogonal Frequency Division Multiple Access (OFDMA)-Passive Optical Network (PON) are disclosed. An optical carrier at a wavelength generated at an optical line terminal (OLT) may be reused by optical network units (ONUs) in the network for upstream transmission of data signals to the OLT. In addition, each ONU may perform carrier suppression to avoid broadband beating noise resulting from the simultaneous transmission of upstream data signals on the same wavelength. Further, the optical source at the OLT used to generate the optical carrier may be reused as a local oscillator for coherent detection of received upstream signals to minimize any frequency offsets. | 08-26-2010 |
20100247104 | Optical Communication System and Method for Generating Dark Return-to-Zero and DWDM Optical MM-Wave Generation For ROF Downstream link using Optical Phase Modulator and Optical Interleaver - A method of generating a dark-RZ pulse in an optical communications system with a dual-arm modulator by setting a direct current bias on the modulator to a specific value such that an output optical power from the modulator achieves a maximum value when the RF signals on the first and second arms of the modulator are off and maintaining the direct current bias at the specific value and applying RF signals to the first and second arms of the modulator and delaying one of the RF signals applied to one of the first and second arms relative to the other of the RF signals such that a dark-RZ pulse is generated with a duty cycle based on the delay. Another aspect of the invention provides a method for generating dense wave division multiplexing (DWDM) optical mm-waves in an optical transmission system by phase modulated DWDM optical signal and applying the phase modulated DWDM optical signal to an input port of an optical interleaver, the optical interleaver having a specified bandwidth to suppress the optical carriers and convert the DWDM optical signal to DWDM optical mm-waves; and amplifying the DWDM optical mm-waves and transmitting the DWDM optical mm-waves over single mode fiber (SMF). | 09-30-2010 |
20100260500 | MULT9-DEGREE WAVELENGTH CROSS-CONNECT USING BIDIRECTIONAL WAVELENGTH SELECTIVE SWITCH - A modular wavelength cross connect node for use in a dense wavelength division multiplexing network exhibiting low cost and improved performance by employing a bidirectional wavelength selective switch in a main optical path and using optical circulators to share any common ports. | 10-14-2010 |
20100309844 | INTEGRATED SENSOR NETWORKS WITH OPTICAL AND WIRELESS LINKS - Systems and methods are disclosed for communicating data in an integrated sensor network having one or more nodes coupled to an optical sensor network and a radio frequency wireless sensor network, each node having an optical link and a wireless link. The method includes determining a transmission path having one or more hybrid hops for packet transmission over the optical sensor network and the radio frequency wireless sensor network, each hybrid hop including optical and wireless links between two neighboring nodes; and selecting a set of optical and wireless links for the optical sensor network and the radio frequency wireless sensor network to minimize contiguous wireless links. | 12-09-2010 |
20100310258 | INTEGRATED SENSOR NETWORKS WITH OPTICAL AND WIRELESS LINKS - A network includes an optical sensor network; and a radio frequency (RF) wireless sensor network coupled to the optical sensor network, wherein the optical sensor network and the RF wireless sensor network communications are coordinated over both optical and wireless links. | 12-09-2010 |
20110085624 | CODED POLARIZATION-MULTIPLEXED ITERATIVE POLAR MODULATION - Systems and methods for optical communication that use a transmitter/receiver. The systems and methods include receiving a modulated, encoded input stream. Channel memory is reduced using coarse digital backpropagation and other channel impairments are removed using turbo equalization. Symbols are detected in the input stream that conform to a non-uniform, polar constellation having a Gaussian source distribution to produce a stream of encoded data. The stream of encoded data is decoded with one or more low density parity check (LDPC) decoders. | 04-14-2011 |
20110085797 | ULTRA WIDE-RANGE FREQUENCY OFFSET ESTIMATION FOR DIGITAL COHERENT OPTICAL RECEIVERS - Methods and systems for receiving an optical signal using cascaded frequency offset estimation. Coherently detecting an optical signal includes compensating for a coarse laser frequency offset between a transmitting laser and a local oscillator laser by determining a maximum phase error (MPE) in the optical signal, compensating for a residual laser frequency offset between the transmitting laser and the local oscillator laser, and decoding data stored in the optical signal. | 04-14-2011 |
20110182428 | SECURE COMMUNICATION OVER PASSIVE OPTICAL NETWORK (PON) WITH QUANTUM ENCRYPTION - Systems and methods to communicate securely includes communicating quantum encryption data on a first wavelength-division multiplexing passive optical network (WDM-PON); and communicating data over separate classical channels of a second WDM-PON, wherein the second WDM-PON synchronizes with the first WDM-PON while providing data communication over the classical channels. | 07-28-2011 |
20110182582 | JOINT SAMPLE RATE CONVERSION AND CD COMPENSATION IN FREQUENCY DOMAIN FOR COHERENT POLMUX - A combined CD compensation and sample rate conversion method performed in the frequency domain. | 07-28-2011 |
20110194855 | SUPERIMPOSED TRAINING AND DIGITAL FILTERING COHERENT OPTICAL RECEIVERS - In a polarization-multiplexing optical communications system, a method and system for coherent reception of polarization-multiplexed optical communications. Training and data sequences are recovered from a plurality of orthogonally polarized signals, such that training and data sequences may be used on a single channel without loss of spectral efficiency. This is accomplished by estimating a channel response for each orthogonally polarized signal based on the mean of the signal and distinguishing between a data sequence and a training sequence in each orthogonally polarized signal. Such distinguishing is accomplished according to an iterative linear minimum mean-square equalization based on the respective channel response estimate. | 08-11-2011 |
20120081780 | LOOK-UP TABLE AND DIGITAL TRANSMITTER BASED ARCHITECTURE FOR FIBER NONLINEARITY COMPENSATION - Systems and methods are disclosed to process an optical signal using a pre-processor to populate a non-linearity compensation data structure based on a set of predetermined rules in a non-real-time off-line mode; and an amplifier applying said predetermined rules in real-time to one or more channel input data using the data structure to determine a non-linearity compensation output. | 04-05-2012 |
20120082468 | LOOK-UP TABLE AND DIGITAL TRANSMITTER BASED ARCHITECTURE FOR FIBER NONLINEARITY COMPENSATION - Systems and methods are disclosed to process an optical signal with a pre-processing module to populate a non-linearity compensation look-up table based on a set of predetermined rules in a non-real-time off-line mode; and a transmitter applying said predetermined rules in real-time to multiple channel input data to generate a real-time symbol pattern, searching the look-up table with the real-time symbol pattern to determine a non-linearity compensation output, and modulating the optical signal with the compensation output. | 04-05-2012 |
20120084617 | MODIFIED PROGRESSIVE EDGE-GROWTH LDPC CODES FOR ULTRA-HIGH-SPEED SERIAL OPTICAL TRANSPORT - Systems and methods enabling ultra-high-speed optical transport The systems and methods include receiving a modulated, encoded input stream. Channel impairments are removed using MAP equalization. Symbols are detected in the input stream to produce a stream of encoded data. The stream of encoded data is decoded with one or more low density parity check (LDPC) decoders that use an LDPC code built by modified progressive edge growth. The LDPC code is built by iteratively expanding trees from each variable node until all check nodes are connected to the respective variable node, while controlling both the local girth and the global girth of the code. | 04-05-2012 |
20120087664 | EFFICIENT MAC PROTOCOL FOR OFDMA PASSIVE OPTICAL NETWORKS (PONS) - Systems and methods are disclosed for providing media access control (MAC) in an optical network by providing a separate control channel and data channel; dedicating each optical network unit (ONU) with one control channel, wherein the control message is transmitted at any time without constraints; sending a grant message to an ONU just before an allocated time is about to start; and sending data traffic from the ONU immediately after receiving the grant message without synchronizing with an optical line terminal (OLT) clock. | 04-12-2012 |
20120099863 | HYBRID OPTICAL/ELECTRICAL SWITCHING SYSTEM FOR DATA CENTER NETWORKS - In one aspect, a system includes one or more electrical switches to transfer data in a data network; one or more optical switching groups coupled to each electrical switch, each switching group having one or more server racks, each server rack coupled to a top of rack (TOR) switch and an optical transceiver coupled to the TOR switch; and an optical switching unit (OSU) coupled to the one or more optical switching groups. | 04-26-2012 |
20120106983 | OPTIMIZED NORMALIZED LEAST MEAN SQUARE PHASE ESTIMATION - Methods and systems for normalized least mean square phase estimation are shown that include receiving optical transmissions that include a modulated signal, determining a step size based on a signal-to-noise ratio (SNR) and a laser linewidth that provides a balance between convergence speed and precision, estimating phase error using the determined step size, derotating the modulated signal to remove the estimated phase error, and demodulating the derotated signal to produce a bitstream. | 05-03-2012 |
20120114341 | SYSTEM AND METHOD FOR FREQUENCY-DOMAIN CHROMATIC DISPERSION AND POLARIZATION MODE DISPERSION COMPENSATION WITH TIME-DOMAIN CHANNEL ESTIMATION - A system and method are disclosed which compensate for chromatic dispersion and polarization mode dispersion in a digital signal. The signal is adjusted for chromatic dispersion in the frequency-domain. The signal is then converted to the time-domain and at least a portion of the signal is estimated to produce channel parameters. The channel parameters are converted to the frequency domain and used to compensate for polarization mode dispersion in the signal. | 05-10-2012 |
20120207470 | SPATIAL DOMAIN BASED MULTI DIMENSIONAL CODED MODULATION FOR MULTI TB PER SECOND SERIAL OPTICAL TRANSPORT NETWORKS - An optical transport network based on multimode/multicore fibers includes a mode-multiplexer to multiplex independent data streams from one or more transmitters; a multimode erbium-doped fiber amplifier (MM EDFA) to compensate for MMF loss; a multimode optical add-drop multiplexer (MM OADM) to add and/or drop multimode channels in multimode networks; a multimode optical cross-connect; and a mode-demultiplexer to separate various mode streams to one or more receivers. | 08-16-2012 |
20120213517 | OPTICAL-LAYER TRAFFIC GROOMING IN FLEXIBLE OPTICAL NETWORKS - Methods and systems for optical signal grooming that include providing one or more input signals, each having one or more modulated subcarriers, to a grooming processor; and grooming the input signals at a subcarrier level with the grooming processor to produce one or more output signals by arranging the modulated subcarriers in the output signals according to a grooming operation such that the modulated subcarriers are not demodulated or decoded prior to grooming. | 08-23-2012 |
20120216093 | SOFT-DECISION NON-BINARY LDPC CODING FOR ULTRA-LONG-HAUL OPTICAL TRANSOCEANIC TRANSMISSIONS - Methods and systems for soft-decision non-binary low-density parity-check (LDPC) coding for ultra-long-haul optical transoceanic transmissions are provided. A receiver includes one or more maximum a posteriori (MAP) equalizers configured to decode one or more symbols of an encoded input stream to provide one or more symbol log-likelihood ratios (LLRs). One or more LLR estimators are configured to estimate the log-likelihood ratios of the one or more symbol LLRs to provide one or more bit LLRs. One or more non-binary LDPC decoders are configured to decode the input stream using the one or more bit LLRs to recover an original input stream. | 08-23-2012 |
20120251110 | COMPUTATIONALLY-EFFICIENT EQUALIZATION IN POLMUX OFDM TRANSMISSION WITH DIRECT-DETECTION VIA JOINT TRANSMITTER AND RECEIVER PROCESSING - A method for joint transmitter and receiver processing for computationally efficient equalization in polarization multiplexed (POLMUX) optical orthogonal frequency division multiplexed (OFDM) transmission with direct detection. | 10-04-2012 |
20120251111 | OPTOELECTRONIC WAVELENGTH CONVERTER FOR POLARIZATION MULTIPLEXED OPTICAL SIGNALS - A wavelength converter that operates on an optical signal having single or multiplexed polarizations and which exhibits any modulation format. | 10-04-2012 |
20120257895 | FOUR-DIMENSIONAL OPTICAL MULTIBAND-OFDM FOR BEYOND 1.4TB/S SERIAL OPTICAL TRANSMISSION - Systems and methods are disclosed to perform four-dimensional optical multiband OFDM communication by organizing an N-dimensional (ND) signal constellation points as a signal matrix; performing 2D-inverse FFT and 2D-FFT to perform modulation and demodulation, respectively; and applying both orthogonal polarizations in the OFDM communication to deal with chromatic dispersion, PMD and PDL effects, and multidimensional signal constellation to improve optical signal-to-noise ratio (OSNR) sensitivity. | 10-11-2012 |
20120257896 | CODED MULTIDIMENSIONAL PULSE AMPLITUDE MODULATION FOR ULTRA-HIGH-SPEED OPTICAL TRANSPORT - Systems and methods are disclosed to provide optical communication by using subcarriers as individual bases functions, obtaining signal constellation points of an N-dimensional pulse amplitude modulation (ND-PAM) constellation diagram as an N-dimensional Cartesian product of a one-dimensional PAM; and transmitting the N-dimensional signal constellation point over all N orthogonal subcarriers serving as individual bases functions. | 10-11-2012 |
20120260142 | FOUR-DIMENSIONAL NON-BINARY LDPC-CODED MODULATION SCHEMES FOR ULTRA HIGH-SPEED OPTICAL FIBER COMMUNICATION - Systems and methods are disclosed for communicating signals, by receiving a K-symbol-long input block from a 2 | 10-11-2012 |
20120263251 | GENERALIZED OFDM (GOFDM) FOR ULTRA-HIGH-SPEED SERIAL OPTICAL TRANSPORT NETWORKS - A coded multidimensional modulation system called generalized OFDM (GOFDM) uses orthogonal subcarriers as bases functions, and the signal constellation points of corresponding multidimensional constellation diagram are obtained as N-dimensional Cartesian product of one-dimensional PAM/two-dimensional QAM. In GOFDM, the N-dimensional/2N-dimensional signal constellation point is transmitted over all N subcarriers/2N-subcarriers, which serve as individual bases functions. Even if some of the subcarriers are severely affected by channel distortion, the overall signal constellation point will face only small distortion, when strong channel capacity achieving channel codes are used. In addition, because the channel capacity is a linear function of number of dimensions, the spectral efficiency of optical transmission systems is significantly improved. Finally, since Euclidean distance of multidimensional signal constellation is much larger that that of two-dimensional signal constellations, OSNR sensitivity is dramatically improved. | 10-18-2012 |
20120263466 | MULTIDIMENSIONAL HYBRID MODULATIONS FOR ULTRA-HIGH-SPEED OPTICAL TRANSPORT - Systems and methods are disclosed with a spatial-domain-based multi-dimensional coded-modulation scheme that improves dramatically OSNR sensitivity and tolerance to fiber nonlinearities by using D-dimensional signal constellations, where D=2(2+M)N. The factor 2 originates from two polarizations, 2+M electrical basis functions are selected (2 in-phase/quadrature channels and M pulse-position like basis functions), and N represents the number of orbital angular momentum (OAM) states used in FMFs/MMFs. For single mode fiber applications N is 1. | 10-18-2012 |
20120269515 | 1 TB/S CONVERGED OPTICAL METRO-ACCESS TRANSMISSION BASED ON WAVELENGTH DIVISION MULTIPLEXED ORTHOGONAL FREQUENCY DIVISION MULTIPLE ACCESS PASSIVE OPTICAL NETWORK (WDM-OFDMA-PON) - A Wavelength Division Multiplexed Orthogonal Frequency Division Multiple Access Passive Optical Network (WDM-OFDMA-PON) includes a passive last-mile optical split terminated by optical network units (ONUs) with OFDMA transceivers; a standard single mode fiber (SSMF) link; a central office optical line terminal (CO-OLT) coupled to SSMF link and the passive last-mile optical split, wherein the CO-OLT comprises an OFDMA transceiver, burst-mode-free operation, inline optical dispersion compensation free operation, and WDM-enabled operation. | 10-25-2012 |
20120301157 | CHROMATIC DISPERSION COMPENSATION USING SIGN OPERATIONS AND LOOKUP TABLES - Methods and devices for compensating for chromatic dispersion are shown that include receiving an input data signal, applying a filter to the data signal, and outputting a CD compensated signal. Applying the filter includes convolving known filter coefficients with a plurality of delayed versions of the data signal using addition and at least one inverse sign operation or using lookup tables and combining outputs to produce a CD compensated signal. | 11-29-2012 |
20120307933 | ENERGY EFFICIENT CONSTELLATION METHOD AND SYSTEM - A method and apparatus employing statistical physics energy minimization methods to signal constellation design. By using statistical physics concepts, an energy-efficient signal constellation design algorithm (EE-SCDA) is described. In the presence of amplified spontaneous emission (ASE) noise and channel impairments, we use EE-SCDA to determine a source distribution, and represent the signal constellation design as a center of mass problem. Furthermore a discrete-time implementation of D-dimensional transceiver as well as corresponding EE polarization-division multiplexed (PDM) system is described. | 12-06-2012 |
20120321318 | CARRIER AND SUBCARRIER HOPPING FOR OPTICAL OFDM SECURITY - Methods and systems for secure communication include assigning data streams to respective orthogonal sub-carriers according to random number information at a transmitter. The data streams are modulated onto the respective orthogonal sub-carriers before the orthogonal sub-carriers are transmitted. The random number information is transmitted on a second medium, separate from the transmission medium. The orthogonal sub-carriers are received from the transmission medium at a receiver, while the random number information is received from the second medium at the receiver. The orthogonal sub-carriers are associated with data streams using the random number information and demodulated to produce data for the associated data stream. | 12-20-2012 |
20130089326 | NONBINARY LDPC CODED MODULATION WITHOUT BANDWIDTH EXPANSION FOR HIGH-SPEED OPTICAL TRANSMISSION - Systems and methods for data transport, comprising encoding one or more streams of input data using nonbinary low density parity check (NB-LDPC) encoders, corresponding to orthogonal polarization states. Receiving one or more streams of input data using a buffer coupled to the encoders, the data written to the buffer bR bits at a time, where R is the code rate. Generating one or more signals using a 2 | 04-11-2013 |
20130091398 | OPTIMUM SIGNAL CONSTELLATION DESIGN FOR HIGH-SPEED OPTICAL TRANSMISSION - Systems and methods for data transport, comprising encoding one or more streams of input data with one or more low density parity check (LDPC) encoders, corresponding to one or more polarization/spatial mode branches. One or more encoded data streams are mapped to symbols, wherein the mapper is configured to assign bits of the symbols to a signal constellation and to associate the bits of the symbols with signal constellation points. A signal constellation is formulated which minimizes a mean-square error of the signal constellation representing the source. The optimum signal constellation size is adjusted to improve transmission quality by adjusting the signal constellation an optical signal to noise ratio (OSNR), wherein the signal constellation is selected using a look-up table (LUT); and the symbols are modulated in accordance with the output of the mapper onto a transmission medium. | 04-11-2013 |
20130091399 | HIGH-SPEED LONG CODEWORD QC-LDPC SOFT DECISION DECODER - A Quasi-Cyclic, LDPC, large girth, soft-decision decoder and accompanying methods. | 04-11-2013 |
20130108270 | VARIABLE BIT-RATE QPSK TRANSMITTER AND METHOD EMPLOYING POLARIZATION MANIPULATION | 05-02-2013 |