Ciena Corporation

Iena Corporation

Shahab Oveis Gharan

Kim Bryon Roberts

Michael Andrew Reimer

Maurice M O'Sullivan

Mahmoud Taherzadehboroujeni

Mohammad Ehsan Seifi

Ramin Babaee

Naim Ben-Hamida

James St Harley

Andrew D Shiner

Martin Bouchard

Amir Keyvan Khandani

Hamid Ebrahimzad

Timothy James Creasy

Qunbi Zhuge

Lukas Jakober

Akbar Ghasemi

Sadok Aouini

Vladimir S Grigoryan

Yuriy Greshishchev

Ahmad Abdo

Kim Byron Roberts

James St Leger Harley

Tung Trong Nguyen

William Martin Snelgrove

Douglas McGhan

Michael Hubbard

Roger Carroll

Yalmez M A Yazaw

Kim B Roberts

Masoud Ebrahimi Tazeh Mahalleh

Mark Edward Rollins

Christian Bourget

Maurice Stephen O'Sullivan

Bertram Leesti

Yves Beaulieu

Ian Roberts

Kendal Zimmer

Maurice O'sullivan

Kim Roberts

Aspects of the subject disclosure may include, for example, obtaining a digital input signal for conversion into analog by a digital-to-analog converter (DAC), and performing filtering operations relating to the digital input signal, wherein the filtering operations provide one or more of pre-compensation for duty-cycle distortion (DCD) associated with the DAC and pre-compensation for bit-level inter-symbol interference (ISI) associated with the DAC. Other embodiments are disclosed.

Duty-cycle distortion (DCD) and bit-level inter-symbol interference (ISI) pre- compensation for a digital-to-analog converter (DAC)

Aspects of the subject disclosure may include, for example, obtaining a signal received at a coherent optical receiver, and equalizing the signal using a filter system, wherein the filter system includes a first filter that provides a first filtering characteristic, a second filter that provides a second filtering characteristic, and a third filter that provides a third filtering characteristic, wherein an adjustment rate of the first filter and an adjustment rate of the second filter are each at least ten times an adjustment rate of the third filter, and wherein the adjustment rate of the first filter is at least ten times the adjustment rate of the second filter. Other embodiments are disclosed.

Method and system for fine frequency finesse filtering

An optical transmitter device includes a digital signal processor (DSP) having digital hardware. The DSP is operative to generate shaped bits from a first set of information bits, and to apply a systematic forward error correction (FEC) scheme to encode the shaped bits and a second set of information bits, where the first set of information bits and the second set of information bits are disjoint sets. Unshaped bits and the shaped bits are mapped to selected symbols or are used to select symbols from one or more constellations. The selected symbols are mapped to physical dimensions. Each unshaped bit is either one of the second set of information bits or one of multiple parity bits resulting from the FEC encoding. In this manner, a target spectral efficiency is achieved.

Probabilistic constellation shaping of multi-dimensional symbols for improved tolerance to nonlinear impairments

Aspects of the subject disclosure may include, for example, obtaining two inputs xand xbased on a digital input signal, and causing a modulator to create two substantially orthogonal output dimensions I and Q based on the two inputs xand x, by performing controlled introduction of a correlation between the two inputs xand xfor the modulator, and detecting a resulting output power of the modulator to facilitate operation of the modulator. Other embodiments are disclosed.

In-phase (I) / quadrature (Q) correlation dither for modulator quadrature control

Aspects of the subject disclosure may include, for example, receiving, at a coherent optical receiver system, Frequency Division Multiplexed (FDM) signals within a spectrum, and equalizing the FDM signals, wherein the equalizing involves creating a plurality of sub-spectra that each corresponds to a respective one of the FDM signals, wherein two sub-spectra of the plurality of sub-spectra have overlapping frequencies, and applying a distinct equalization to each of the plurality of sub-spectra, resulting in distinct equalizations, wherein at least two of the distinct equalizations have substantially independent control. Other embodiments are disclosed.

Method and system for equalizer control per frequency division multiplexed (FDM) signal

Aspects of the subject disclosure may include, for example, obtaining a data signal that includes a stream of symbols, modifying the data signal, resulting in a modified data signal, such that there is inter-symbol interference (ISI) when the modified data signal is received by a receiver, and transmitting the modified data signal over a channel to the receiver, wherein the ISI is distinct from an inverse of the channel and is introduced based on the modifying to be exploited by a decoder in the receiver for enhanced decoding. Other embodiments are disclosed.

Non-linear precoding for maximum likelihood sequence estimation (MLSE) receiver

Aspects of the subject disclosure may include, for example, identifying a modulation scheme for transmitting data from a transmitter to a receiver, identifying a plurality of symbols associated with the modulation scheme, determining that a transfer function of a filter that is applied at the transmitter imposes an interdependence amongst at least two symbols of the plurality of symbols, determining, based on the transfer function, a joint probability distribution of the plurality of symbols that reduces a signal power of at least one signal that is used to transmit the data subject to a constraint that an information rate associated with the at least one signal is greater than a threshold, and causing the data to be transmitted via the at least one signal from the transmitter to the receiver in accordance with the joint probability distribution. Other aspects are disclosed.

Apparatuses and methods for facilitating joint precoding and probabilistic constellation shaping

A system is configured to measure () a forward error correction (FEC) decoding property () associated with applying FEC decoding () to FEC-encoded bits or symbols at a receiver device () deployed in a communication network (). The system is configured to provide () an assessment of operating conditions of the receiver device based on the FEC decoding property. The FEC decoding property comprises, for example, a distribution of a number of iterations of a FEC decoding operation applied to a plurality of FEC blocks processed within a period of time. In some examples, the FEC decoding property comprises any one of heat, temperature, current, voltage, active clock cycles, idle clock cycles, activity of parallel engines, activity of pipeline stages, and input or output buffer fill level of the FEC decoding. The assessment is based, for example, on a comparison between the FEC decoding property and reference FEC data ().

Assessing operating conditions of a receiver in a communication network based on forward error correction decoding properties

An apparatus comprises circuitry configured to generate a predicted error signal by applying to a digital signal a distortion model characterized by parameters configured to model circuit component mismatches in a digital-to-analog converter (DAC), circuitry configured to generate a pre-compensated digital signal using the digital signal and the predicted error signal, and circuitry configured to provide the pre-compensated digital signal to the DAC for conversion into an analog signal.

Digital-to-analog converter (DAC) distortion pre-compensation

An optical transmitter device () includes a digital signal processor 'DSP' () having digital hardware (). The DSP is operative to generate () shaped bits from a first set of information bits, and to apply () a systematic forward error correction 'FEC' scheme to encode the shaped bits and a second set of information bits, where the first set of information bits and the second set of information bits are disjoint sets. Unshaped bits and the shaped bits are mapped to selected symbols or are used to select symbols from one or more constellations. The selected symbols are mapped to physical dimensions. Each unshaped bit is either one of the second set of information bits or one of multiple parity bits resulting from the FEC encoding. In this manner, a target spectral efficiency is achieved.

An optical system includes a transmitter including transmitter circuitry configured to cause transmission of a transmitted optical signal over a fiber link on an X polarization and a Y polarization; and a receiver including receiver circuitry configured to receive a received optical signal from the fiber link on the X polarization and the Y polarization, wherein the transmitter circuitry is configured to cause State of Polarization (SOP) changes on the X polarization and the Y polarization for a test of the fiber link. The transmitter circuitry and the receiver circuitry are built-in with the transmitter and the receiver, respectively, for performance of the test.

Built-in jitter loading and state of polarization generation to characterize optical transceivers

A digital-to-analog converter (DAC) comprises circuitry configured to generate, based on a mapping, L signals representing an N-bit digital input, wherein N and L are positive integers, and wherein N&#x3c;L&#x3c;2&#x2212;1, and circuitry configured to control current flow from L weighted current sources using the L respective signals, thereby generating an analog output that uniquely represents the N-bit digital input, wherein the weighted current sources have weights configured to minimize at least one error metric associated with the analog output.

Digital-to-analog converter (DAC) architecture optimization

In data communications, a suitably designed contrast coding scheme, comprising a process of contrast encoding () at a transmitter end () and a process of contrast decoding () at a receiver end (), may be used to create contrast between the bit error rates 'BERs' experienced by different classes of bits. Contrast coding may be used to tune the BERs experienced by different subsets of bits, relative to each other, to better match a plurality of forward error correction 'FEC' schemes () used for transmission of information bits (), which may ultimately provide a communications system () having a higher noise tolerance, or greater data capacity, or smaller size, or lower heat.

Forward error correction with outer multi-level code and inner contrast code

A transmitter () generates () an encoded vector () by encoding () a data vector (), the encoded vector representing payload information and parity information. The encoding is mathematically equivalent to calculating three or more forward error correction (FEC) codewords from the data vector and then calculating the encoded vector from the codewords, at least one codeword being calculated from at least one recursion of a mathematical operation, and at least one codeword comprising more than 6 terms. The transmitter transmits () a signal representing the encoded vector over a communication channel. A receiver () determines () a vector estimate () from the signal and recovers () the data vector from the vector estimate by sequentially decoding () the codewords, wherein at least one codeword that is decoded earlier in the decoding enhances an estimate of at least one codeword that is decoded later in the decoding.

Forward error correction coding using a tree structure

Upon receiving a communications signal conveying symbols at a symbol period T, a receiver applies filter coefficients to a digital representation of the communications signal, thereby generating filtered signals having a shape in the frequency domain characterized by a bandwidth expansion factor &#x3b1;, where components of the filtered signals correspond to angular frequencies The receiver calculates first-order components from a first phase derivative of the components at a first differential distance, second-order components from a second phase derivative of the first-order components at a second differential distance, and composite second-order components from an average of the second-order components over multiple time intervals. Using the composite second-order components, the receiver calculates at least one of (i) an estimate of residual chromatic dispersion (CD) associated with the filtered signals, and (ii) an estimate of carrier frequency offset (CFO) associated with the filtered signals.

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Ottawa, Canada

Shahab Oveis Gharan