At+t Corp.

At&t Intellectual Property I, L.p.

Lucent Technologies Inc.

Other

USA As Represented by Secretary of the Navy

Nicholas J Frigo

Patrick P Iannone

Kenneth Charles Reichmann

Mikhail Boroditsky

Peter David Magill

Aleksandra Smiljanic

Mikhail Brodsky

Cedric F Lam

Mark David Feuer

Thomas Edward Darcie

Martin Birk

Sheryl Leigh Woodward

Robert William Tkach

Lih-Yuan Lin

Evan Lee Goldstein

Chuan Pu

Meredith N Hutchinson

Keith Wayne Goossen

James Albert Walker

William K Burns

David A Miller

David John Bishop

Bradley Paul Barber

Peter Ledel Gammel

Anthony Dandridge

Robert P Moeller

Adel A Saleh

Alan B Tveten

Vincent J Urick

Mikhail Borditsky

Caitlin R S Williams

A communication system includes an optical receiver that receives a modulated optical signal and converts same back to electrical form by a photodiode. The photodiode includes an optical input and a dc bias input, and outputs a photocurrent. The optical communication system includes a photodiode linear operation point feedback loop communicating with the photodiode based on an intermodulation distortion contour plot corresponding to the photodiode. The intermodulation distortion contour plot includes a plurality of linear operation points for the photodiode. The photodiode linear operation point feedback loop operates the photodiode at a respective operation point of the plurality of linear operation points. Optionally, the photodiode linear operation point feedback loop includes a voltage-biasing feedback loop receiving the photocurrent and outputting to the dc bias input a bias voltage based on the intermodulation distortion contour plot, and/or an optical power regulating feedback loop communicating with the optical input.

Reduction of photodiode nonlinearities by adaptive biasing

A method, apparatus and system for minimally intrusive fiber identification includes imparting a time-varying modulation onto an optical signal propagating in an optical fiber and subsequently detecting the presence of the time-varying modulation in the optical signal transmitting through the fiber to identify the fiber. In a specific embodiment of the invention, a time-varying curvature is imposed on the fiber to be identified and the presence of the resultant time variation in the transmitted power of a propagating optical signal is subsequently detected for identification of the manipulated fiber.

Method, apparatus and system for minimally intrusive fiber identification

A method of suppressing polarization-dependent loss in a signal. A constant-intensity, analog, optical signal with modulating polarization is transmitted through an optical communications link. The constant-intensity, analog, optical signal with modulating polarization includes an analog radio frequency signal impressed upon a polarization-modulated, laser signal. A polarization-dependent loss of the communications link is determined, the polarization-dependent loss inducing an induced phase shift in the constant-intensity, analog, optical signal with modulating polarization. The constant-intensity, analog, optical signal with modulating polarization is re-oriented using a polarization transformer so as to suppress the induced phase shift.

Method of suppressing polarization-dependent loss in polarization-modulated photonic links

A packet-switched WDMA ring network has an architecture utilizing packet stacking and unstacking for enabling nodes to access the entire link capacity by transmitting and receiving packets on available wavelengths. Packets are added and dropped from the ring by optical switches. A flexible credit-based MAC protocol along with an admission algorithm enhance the network throughput capacity.

High-capacity packet-switched ring network

Described is a method and system for reducing system penalty from polarization mode dispersion. The method includes receiving a plurality of signals at a receiving end of a transmission line, each signal being received on one of a plurality of channels of the transmission line and measuring a signal degradation of at least one of the channels of the transmission line. An amount of adjustment of a polarization controller is determined based on the signal degradation, the amount of adjustment being selected to reduce the polarization mode dispersion. The amount of adjustment is then transmitted to the polarization controller.

Method and apparatus for broadband mitigation of polarization mode dispersion

A system and method for a transparent WDM metro ring architecture in which optics enables simultaneous provisioning of dedicated wavelengths for high-end user terminals, while low-end user terminals share wavelengths on 'virtual rings'. All wavelengths are sourced by the network and remotely modulated at customer 'End Stations' by low cost semiconductor optical amplifiers, which also serve as transmission amplifiers. The transparent WDM metro ring architecture permits the communication of information and comprises a fiber optical feeder ring, at least one fiber optical distribution ring, a network node (NN), at least one access node (AN) said network node and said at least one access node connected via said fiber optical feeder ring and at least one end station (ES) connected via said fiber optical distribution ring to said at least one access node, wherein said user is attached to said at least one end station.

System and method for operating transparent node for WDM shared 'virtual ring' networks

A system and method for a transparent WDM metro ring architecture in which optics enables simultaneous provisioning of dedicated wavelengths for high-end user terminals, while low-end user terminals share wavelengths on 'virtual rings'. All wavelengths are sourced by the network and remotely modulated at customer 'End Stations' by low cost semiconductor optical amplifiers, which also serve as transmission amplifiers. The transparent WDM metro ring architecture permits the communication of information and comprises a fiber optical feeder ring, at least one fiber optical distribution ring, a network node (NN), at least one access node (AN) said network node and said at least one access node connected via said fiber optical feeder ring and at least one end station (ES) connected via said fiber optical distribution ring to said at least one access node, wherein said user is attached to said at least one end station. A simple node that supports bi-directional propagation in transparent WDM metro architectures using &#x201c;virtual rings&#x201d; is also described. A method for communicating information over a WDM fiber optical ring network architecture in a metro access arena using one or more wavelengths, which can be shared by a plurality of user terminals, each user terminal coupled to an end station comprises the steps of sending downstream data packets, sending optical chalkboard packets consisting of ones and sending control signals.

Method for operating transparent node for WDM shared 'virtual ring' networks

A method of determining a mean square differential group delay associated with a length of optical fiber. The method including measuring a polarization mode dispersion vector as a function of frequency, using a frequency-domain polarization mode dispersion measurement apparatus. The method also including calculating a second-order polarization mode dispersion vector as a function of frequency by calculating a derivative of the polarization mode dispersion vector with respect to frequency. Also, calculating the mean of the magnitude of the second-order polarization mode dispersion vector to obtain a first result. Further, multiplying a proportionality coefficient by the first result to calculate the mean square differential group delay.

Method for increasing accuracy of measurement of mean polarization mode dispersion

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Red Bank, NJ, United States of America

Nicholas J Frigo