Ciena Corporation

Nortel Networks Corporation

Rockstar Consortium US LP

Other

Northern Telecom Limited

Rockstar Bidco, LP

Ciena Luxembourg S.a.r.l.

James St Harley

Kim Bryon Roberts

David W Boertjes

Shahab Oveis Gharan

Gerard Leo Swinkels

Michel Belanger

David Miedema

Richard A Habel

Maurice Stephen O'Sullivan

Michael Watford

Douglas McGhan

Paul Littlewood

Michael Y Frankel

Han Henry Sun

Alan Glen Solheim

Kim Byron Roberts

John P Mateosky

Ronald Joseph Gagnon

Lukas Jakober

Kevin S Meagher

Mark Andrew Hawryluck

Nigel Baker

Jamie Gaudette

Duncan John Forbes

Ian Hardcastle

Mohammad Sotoodeh

Giuseppe Bordogna

Roger Carroll

Bilal Riaz

Anant Grewal

Chuandong Li

David John Danagher

Lacra Pavel

Bipin Patel

Elizabeth Rivera Hartling

Takis Hadjifotiou

Chandra Sekhar Bontu

Leo L Strawczynski

Maurice M O'Sullivan

Naim Ben-Hamida

Sadok Aouini

Michael Andrew Reimer

Andrew D Shiner

Kuang Tsan Wu

Timothy James Creasy

Mark Edward Rollins

David Damian Nicholas Bevan

Christian Bourget

Michael Mayer

Qunbi Zhuge

Genzao Zhang

Ahmad Abdo

Manoj Verghese

Feng Shi

Marc Veilleux

Avid E Lemus

Jeffrey Alan Weslowski

Ruibin Jin

Saeid Seynejad

Kendal Zimmer

Philippe Neusy

Saeid Seydnejad

Yuan Jiang

Maurice O'sullivan

Michel Belander

Paul A Littlewood

A receiver is configured to generate a digital signal representative of data conveyed by a communication signal detected at the receiver, and to apply digital signal processing to the digital signal, thereby generating a processed signal. The receiver is further configured to determine a relative noise estimate for the processed signal, and to load an amount of digital noise into the digital signal processing based on a difference between the relative noise estimate and a target. As a result of the digital noise loading, improved stability of at least one control loop in the receiver may be achieved.

Receiver noise loading for control loop stability

Managing clock-data recovery for a modulated signal from a communication channel comprises: receiving the modulated signal and providing one or more analog signals, providing one or more digital input streams from samples of the analog signals, and processing the digital input streams to provide decoded digital data. The processing comprises: determining the decoded digital data based on information modulated over a plurality of frequency elements associated with the modulated signal, based at least in part on transforms of the digital input streams; a clock signal based on clock recovery from the digital input streams; and determining a clock phase error estimate associated with the determined clock signal based at least in part on a sum that includes different weights multiplied by different respective summands corresponding to different sets of frequency elements.

Estimating clock phase error based on channel conditions

A processor of an apparatus is configured to apply one or more control algorithms using estimated data to adjust the one or more control parameters of a section of an optical fiber network. The estimated data are derived from measurements of optical signals in the section and from knowledge of the section. The estimated data is a function of optical nonlinearity and of amplified spontaneous emission.

Adjustment of control parameters of section of optical fiber network

A method, a controller, and an optical network element are configured to perform steps of monitoring one or more optical links each formed by optical transceivers which are configured to provide variable capacity via a plurality of modulation formats; based on the monitoring, causing corresponding optical transceivers for the one or more optical links to operate at a first modulation format different from a second modulation format providing excess capacity; and mapping the excess capacity to bandwidth useable by one or more services managed by the one or more of the management system, the management plane, and the control plane.

Systems and methods for managing excess optical capacity and margin in optical networks

Multiple receivers are comprised in a flexible coherent transceiver of a multi-span optical fiber network. Each of the multiple receivers is operative to handle communications on a respective channel. The multiple receivers measure optical characteristics. For each of the multiple receivers, the optical characteristics include optical nonlinear interactions on the respective channel, the optical nonlinear interactions being at least partially dependent from one span to another span. An optical power of a signal on each of the multiple channels is adjusted as a function of the optical characteristics.

Power control in an optical fiber network

A method, a network element, and a network include determining excess margin relative to margin needed to ensure performance at a nominal guaranteed rate associated with a flexible optical modem configured to communicate over an optical link; causing the flexible optical modem to consume most or all of the excess margin, wherein the capacity increased above the nominally guaranteed rate includes excess capacity; and mapping the excess capacity to one or more logical interfaces for use by a management system, management plane, and/or control plane. The logical interfaces can advantageously be used by the management system, management plane, and/or control plane as one of restoration bandwidths or short-lived bandwidth-on-demand (BOD) connections, such as sub-network connections (SNCs) or label switched paths (LSPs).

Adjustment of one or more control parameters of a section of an optical fiber network involves taking measurements of optical signals in the section, deriving estimated data from the measurements and from knowledge of the section, where the estimated data is a function of optical nonlinearity and of amplified spontaneous emission, and applying one or more control algorithms using the estimated data to adjust the one or more control parameters.

A transmitter comprises a complex mixer to generate a single I analog drive signal and a single Q analog drive signal, and a single multi-dimensional optical modulator configured to modulate an optical carrier light using the single I analog drive signal and the single Q analog drive signal to produce a modulated optical signal for transmission. Alternatively, a transmitter comprises a complex mixer to generate two I analog drive signals and two Q analog drive signals, and a single multi-dimensional multiple-electrode optical modulator configured to modulate an optical carrier light using the analog drive signals to produce a modulated optical signal for transmission. In both transmitters, the optical carrier light is produced by a single laser, and frequency components of the first data signal are located in a different portion of a spectrum of the modulated optical signal than frequency components of the second data signal.

Frequency domain multiplex optical transmission

Forward Error Correction technique: parity vectors are computed such that each parity vector spans multiple FEC frames; in a given FEC frame, a first set of syndrome bits are due to the parity vectors, and a second set of syndrome bits satisfy FEC equations that involve bits of the given FEC frame including the first set of syndrome bits; and the parity vectors are staggered with respect to any sequence in which the FEC frames are processed. Values of decoded bits of a first frame are deduced from known bits of a first parity vector having an effective length of one frame. For parity vectors having an effective length greater than one frame, a Log Likelihood Ratio of each unknown bit associated with the first frame is updated based on known and unknown bits of each parity vector. First frame is decoded using deduced bit values and updated LLR values.

Staggered parity

Managing performance of an optical communications network may be facilitated by digital noise loading techniques. The digital noise loading techniques may include measuring a quality of a communication signal received at a coherent optical receiver, applying digital noise to the communication signal at the coherent optical receiver, and detecting a change in the quality of the communication signal at the coherent optical receiver in response to the application of the digital noise. Based on the change in the quality of the communication signal, an operating characteristic and/or a performance margin of the coherent optical receiver may be determined, prompting or facilitating further actions such as adjusting one or more operating parameters of the optical communications network and/or triggering an alert.

Digital noise loading for optical receivers

In a Forward Error Correction (FEC) technique, parity vectors are computed such that: each parity vector spans a set of frames; a subset of bits of each frame is associated with parity bits in each parity vector; and a location of parity bits associated with one frame in one parity vector is different from that of parity bits associated with the frame in another parity vector. Values of decoded bits of a first frame are deduced from known parity bits of a first parity vector having an effective length of one frame. For parity vectors having, an effective length greater than one frame, a Log Likelihood Ratio of each unknown parity bit associated with the first frame is updated based on known and unknown parity bits of each parity vector. The first frame is decoded using the deduced bit values and the updated LLR values.

Described are an optical communications system and a method that allow for compensation of chromatic dispersion and polarization mode dispersion imparted to a communications signal propagating through an optical link. The system is based on a cost-effective optical transport architecture that accommodates baud rates exceeding 15 Gbaud and eliminates the need for costly optical dispersion compensators. Compensation for polarization mode dispersion is performed at the receiver using nonlinear processing. Advantageously, direct detection modulation using inexpensive electro-optic system components can be used in place of more costly and complex coherent and differential modulation formats. Digital filtering can be performed at the transmitter and the input signal can be inverted based on the nonlinearity of the transmitter electro-optic components. Consequently, the bandwidth and linearity requirements for the transmitter electro-optic components are relaxed, and cost reductions are realized.

Optical communications system having chromatic dispersion and polarization mode dispersion compensation

A method of transmitting a data signal in an optical communications system. The method includes processing the data signal to generate an analog drive signal, wherein the processing comprises applying a first non-linear operation such that frequency components of the drive signal lay in at least two separated spectral bands. An optical carrier light is modulated using the analog drive signal.

A method, a network element, and a network include determining excess margin relative to margin needed to insure performance at a nominal guaranteed rate associated with a flexible optical modem configured to communicate over an optical link; causing the flexible optical modem to consume most or all of the excess margin, wherein the capacity increased above the nominal guaranteed rate includes excess capacity; and mapping the excess capacity to one or more logical interfaces for use by a management system, management plane, and/or control plane. The logical interfaces can advantageously be used by the management system, management plane, and/or control plane as one of restoration bandwidth or short-lived bandwidth-on-demand (BOD) connections, such as sub-network connections (SNCs) or label switched paths (LSPs).

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Ottawa, Canada

James St Harley