Patent application number | Description | Published |
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 |
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 |
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 |
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 |
20110255864 | CARRIER FREQUENCY OFFSET (CFO) ESTIMATOR WITH LOW COMPLEXITY AND HIGH ACCURACY FOR ORTHOGONAL-FREQUENCY-DIVISION-MULTIPLEXING (CO-OFDM) SYSTEMS - A system and method are provided for carrier frequency offset (CFO) estimation for coherent optical orthogonal-frequency-division-multiplexing (CO-OFDM) broadband systems. The method includes obtaining an initial estimate of a normalized CFO with an estimation range equal to ±L/2 subcarrier subspacing using a single training symbol with L identical portions. The method further includes obtaining a maximum likelihood (ML) estimate of the CFO by performing a local grid search based on the initial estimate. | 10-20-2011 |
20110310951 | COMPUTATIONALLY-EFFICIENT MIMO EQUALIZATION ALGORITHM FOR HIGH-SPEED, REAL-TIME, ADAPTIVE POLARIZATION MULTIPLEXED (POLMUX) OFDM TRANSMISSION WITH DIRECT DETECTION - A polarization-multiplexed (POLMUX) optical orthogonal frequency division multiplexing (OFDM) system with direct detection includes an adaptive dual POLMUX carrier OFDM transmitter; and a block symmetric (B-S) MIMO equalizer coupled to the adaptive dual POLMUX carrier OFDM transmitter through a standard single-mode-fiber (SSMF) feedback path. | 12-22-2011 |
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 |
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 |
20120213523 | OPTICAL-LAYER TRAFFIC GROOMING AT AN OFDM SUBCARRIER LEVEL WITH PHOTODETECTION CONVERSION OF AN INPUT OPTICAL OFDM TO AN ELECTRICAL SIGNAL - A method for optical layer traffic grooming includes receiving at least two optical input signals into respective optical receivers, each optical receiver having a photodetector for converting the respective optical input signal into a respective electrical signal; a grooming processor responsive to the electrical signals, the grooming processor being a radio frequency RF processor for processing the electrical signals at a subcarrier level to produce an RF orthogonal frequency division multiplexing signal OFDM signal; and modulating the groomed RF OFDM signal at a transmitter for conversion of the groomed RF OFDM into an optical signal. | 08-23-2012 |
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 |
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 |
20120257897 | Energy Efficient OFDM Transceiver - An energy efficient OFDM transceiver includes a transmitter using a decision processor to control first internal elements that can be operated in parallel and can be selectively powered off or hibernated, and a receiver using a processing decision element to control second internal elements that can be operated in parallel and can be selectively powered off or hibernated, wherein control of the first and second internal elements enables tracking status of network traffic, adjustment of OFDM bandwidth based on a traffic decision and selectively powering off or hibernating parallel ones of the first and second internal elements. | 10-11-2012 |
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 |
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 |
20130089340 | HIGH-SPEED OPTICAL 8-QAM MODULATION BY CASCADING DUAL-DRIVE MACH-ZEHNDER MODULATOR WITH I/Q MODULATOR - Structures and methods of generating 8-QAM signals through the effect of a cascaded I/Q modulator and Mach-Zhender modulator. The 8-QAM signals are generated by applying one binary sequence to the dual-drive Mach-Zehnder modulator (MZM) and two binary sequences to the I/Q modulator. Operationally, the I/Q modulator generates QPSK constellation(s), while the dual drive MZM either maintains the QPSK constellation at an out ring, or attenuates its amplitude to the inner ring and rotates its phase by π/4 phase depending on the binary data it was driven by. | 04-11-2013 |
20130108270 | VARIABLE BIT-RATE QPSK TRANSMITTER AND METHOD EMPLOYING POLARIZATION MANIPULATION | 05-02-2013 |
20130259174 | Method and System for Pilot-Based Time Domain Phase Noise Mitigation for Coherent Receiver - A method for phase noise mitigation for a coherent receiver in either an OFDM or single carrier based transmission system including applying a frequency offset and coarse phase noise compensation based on a radio frequency RF tone or using a phase lock loop PLL m-th power procedure, responsive to a signal from a digital signal processed transmission with an added pilots signal over an optical system, applying fine phase noise compensation based on comparison of the pilots signal in a time domain, removing the pilots, and demodulating the remaining pilotless signal. | 10-03-2013 |
20140056585 | Next Generation Optical Access Network with Centralized Digital OLT - An optical access network with centralized digital optical line termination OLT including an optical line termination unit having a digital transmitter and a coherent receiver for downstream signal transmitting and upstream signal receiving, and at least one optical network unit ONU with transceiver functions for communicating with the OLT over an optical path, the ONU including intensity modulation and single photodiode detection, wherein the digital transmitter includes digital signal processing DSP, digital-to-analog conversion DAC and analog-to-digital conversion ADC functions that can be shared by all multiple ones of the ONU in the network, the DSP reducing or removing dispersion and non-linearity effects in the network and the coherent receiver enabling performance of the downstream stream signal transmitting to match that of the upstream signal receiving in the OLT. | 02-27-2014 |
20140099128 | Inter-band cross-phase modulation compensation for the mitigation of intra-channel nonlinear impairments in optical fiber transmission - An optical communication system includes a digital signal processer coupled to the coherent receiver, said coherent receiver including a nonlinearity compensation module for compensating for nonlinear effects in fiber in the optical link for increasing capacity or transmission distance of the fiber, the nonlinearity compensation module includes a spectral slicing of the signal into bands, computing nonlinear interaction between the bands with parameters opposite to those of the fiber to reverse the non-linear effects in the fiber, and only certain nonlinear interactions between bands are considered thereby reducing complexity of the nonlinearity compensation. | 04-10-2014 |
20140269980 | Look-Up Table Based Digital Filter Array Using Digital Transmitter - Disclosed are structures and methods for slicing a broadband signal into multiple, narrower bandwidth sub-bands through the use of a look-up table (LUT). An input broadband signal is first loaded by a pre-defined LUT. The LUT is designed with multiple parallel outputs, wherein each output is one individual sub-band. | 09-18-2014 |
20140314104 | Flexible Remote Node (RN) For Dynamic Traffic Allocation in Passive Optical Networking (PON) and Mobile Backhaul (MBH) Applications - A computer implemented method for dynamically allocating traffic in a passive optical communication system includes employing an individual wavelength channel to carry different data services from an individual transmitter, configuring an optical network unit into optical network unit groups serving at least two community of users; and providing a flexible remote node with wavelength routing flexibility including switching wavelength traffic from optical network user groups with low capacity requirements to optical network user groups with increased wavelength traffic requirements. | 10-23-2014 |
20140314411 | OPTICAL NYQUIST SUPERCHANNEL GENERATION USING MICROWAVE LOW-PASS FILTERING AND OPTICAL EQUALIZATION - Disclosed are structures and methods for generating a Nyquist superchannel. | 10-23-2014 |