Tyco Electronics Subsea Communications LLC

Tyco Telecommunications (us) Inc.

Cisco Technology, Inc.

Acacia Communications, Inc.

Subcom, LLC

Hongbin Zhang

Hussam G Batshon

Carl R Davidson

Yi Cai

Ralph Brian Jander

Alexei N Pilipetskii

Jin-Xing Cai

R Brian Jander

Yu Sun

Mehmet Aydinlik

Oleg V Sinkin

Robert Roger Cordell

Ram M Engira

Thomas R Lawrence

Maxim A Bolshtyansky

Haifeng Li

Georg Heinrich Mohs

Dmitri G Foursa

Christian Rasmussen

Tymon Barwicz

Lee Richardson

Sheng Zhang

Charles Breverman

Li Liu

Murat Azizoglu

A receiver configured to receive a plurality of symbols is disclosed. The receiver includes a hard decision decoder, a look-up table (LUT) coupled to the hard decision decoder, and a soft metric generator coupled to the LUT. The hard decision decoder is to receive a first set of symbols from the plurality of symbols and provide a set of hard coded neighboring symbols to the LUT. The first set of symbols comprises a center symbol with neighboring symbols. The LUT is to store a value representative of the center symbol that is addressable by the set of hard coded neighboring symbols. The soft metric generator is to calculate bit log likelihood ratio (LLR) values based on the center symbol and the value representative of the center symbol stored in the LUT.

Maximum a posteriori detector for linear and nonlinear channel impairment

A method, system and apparatus for mapping a symbol from a N-QAM constellation into a binary bit set, where N is the number of symbols in the constellation, and reducing the length of the binary bit set according to at least one property of nonlinear distortion by generating a lookup table (LUT) address from a LUT address generator, and adding the LUT address to a LUT of size smaller than N{circumflex over ( )}(2M+1), where 2M is the number of neighboring symbols to be stored.

Efficient nonlinear equalizer for transmitter predistortion

Disclosed is a coherent optical transceiver for optical communication including a transmitter, a receiver, and a PIC. The transmitter includes a DAC and a driver. A modulator in the PIC limits a signal spectrum of an output optical signal within a Nyquist frequency band. The receiver receives an input optical signal from the PIC and converts the input optical signal to an input analog electrical signal. An ADC converts the input analog electrical signal into an input digital electrical signal indicative of the input optical signal at an ADC sampling rate. The DSP includes a linear filter to equalize intersymbol interference, a post filter, and an MLSE to determine symbols corresponding the input optical signal. The driver and the post filter are first order filters with transfer function G(z)=1+az−1, where a is between 0 and 1.

Coherent optical module for short reach communications

A method, apparatus, and computer program product for estimated transmit skew comprising restoring an I component and a Q component of a signal, extracting clock information from the I component, extracting clock information from the Q component, and determining the skew between the I component and the Q component using the extracted clock information from the I component and the extracted clock information from the Q component.

Estimating transmitter skew

A method, system, and apparatus for a coherent optical breakout; wherein the optical breakout has a laser; wherein the coherent optical breakout has a set of optical connections; wherein the set has at least two optical connections; wherein the coherent optical breakout enables coherent optical communication of X Gbs across each of the set of optical connections.

Coherent optical breakout

Quadrature amplitude modulation (QAM) techniques for use in optical systems are described. An optical transceiver may include a modulator configured to modulate data according to a scaled set-partitioning QAM (SP-QAM) scheme. The modulator may be configured to receive a plurality of bits, associate the plurality of bits with a plurality of symbols according to the scaled (SP-QAM) scheme; and transmit the plurality of symbols over an optical channel. A demodulator in an optical receiver may receive the plurality of symbols transmitted over the optical channel and associate the received symbols with a plurality of bits according to the scaled (SP-QAM) scheme; and provide the plurality of bits to a forward error correction decoder.

Modulation systems and methods in optical transceivers

A system and method including multi-dimensional coded modulation wherein symbols within successive blocks of symbols are mapped using at least two different constellations to differentiate the symbols from each other. At least one data bit is encoded by an order of the symbols within each block of symbols. The receiver decodes the data by decoding at least one bit from the order of the symbols mapped with the first and second constellations.

System and method for multi-dimensional modulation using multiple constellations

An adaptive equalizer with coefficients determined by averaging an estimated filter coefficient over a number, N, of past and future symbols. Estimated filter coefficients may be optimized by optimization of the number N, an averaging window function and a scaling factor using a metric. The metric also allows estimation of the amount of noise that may be compensated by an adaptive equalizer consistent with the present disclosure.

Adaptive equalizer with coefficients determined using groups of symbols to compensate for nonlinear distortions in optical fiber communications

A system and method including a parity bit encoder for encoding each n&#x2212;3 bits of data to be transmitted with three parity check bits to produce blocks of n bits (n&#x2212;3 information bits plus three parity bits associated with the n information bits). Each of the blocks of n bits are Gray mapped to three QAM symbols that are modulated onto an optical wavelength and transmitted to a receiver. A maximum a posteriori (MAP) decoder is used at the receiver to correct for cycle slip.

System and method using cascaded single partity check coding

A system and method with a modified bit-interleaved coded modulation with iterative decoding (BICM-ID). Coded and interleaved bits are combined and coded with a second FEC code that is then mapped to a modulation format. The second FEC code may be a single parity check (SPC) and the scheme may be referred to as a SPC-BICM-ID scheme.

System and method including modified bit-interleaved coded modulation

A system and method involving a coded modulation scheme whereby different spectral efficiencies can be achieved for different transmitters in a WDM system using the same M-QAM modulation format. A maximum achievable spectral efficiency for the transmitters may be selected and a spectral efficiency step-size of the maximum achievable spectral efficiency may be specified. The spectral efficiency for any transmitter in the system may be individually selected by reducing its spectral efficiency from the maximum achievable spectral efficiencies by a selected number of steps corresponding to the step size.

Coded modulation for small step-size variable spectral efficiency

A system and method including a parity bit encoder for encoding bits of data to be transmitted with first and second parity check bits to produce successive block of bits. Each of the blocks of bits are Gray mapped to a plurality of associated QAM symbols that are modulated onto an optical wavelength and transmitted to a receiver. A de-mapper corrects for 90 degree and 180 degree cycle slip using parity indicated by the first and second parity bits.

System and method for cycle slip correction

A repeater that enables both bi-directional optical time domain reflectometry (OTDR) and loop gain monitoring techniques that may be employed, for example, in particularly long repeater spans. In one embodiment, the repeater includes high loss loopback (HLLB) paths configured to couple test signals between incoming and outgoing fiber paths. The HLLB paths are coupled from the outputs to the inputs of amplifiers within the repeater and couple both OTDR and loopback signals from an outgoing fiber path to an incoming fiber path so that may be returned to line monitoring equipment that transmitted the test signals.

Growing community of inventors

Marlboro, NJ, United States of America

Hongbin Zhang