At+t Corp.

AT&T Intellectual Property I, LP

Tyco Telecommunications (us) Inc.

Red Sky Systems, Inc.

At&t Bell Laboratories

Red Sky Subsea, Ltd.

Lucent Technologies Inc.

Huawei Marine Networks Co., Ltd.

Jonathan A Nagel

Sheryl Leigh Woodward

Mark Shtaif

Antonio Mecozzi

Moshe Tur

Michael H Eiselt

Sergey Yurevich Ten

Stephen G Evangelides, Jr

David John DiGiovanni

Alexei N Pilipetskii

Morten Nissov

John L Zyskind

James W Sulhoff

Ekaterina A Golovchenko

Richard G Smart

Michael J Neubelt

Carl A B Clausen

Samia M Bahsoun

Robert William Tkach

Andrew Roman Chraplyvy

Jean-Marc P Delavaux

Daniel A Fishman

Lynn Nelson

Yong-Kwan Park

Nigel Hunt Taylor

Joseph D Evankow

Systems and methods for calculating a relative temperature of a fiber-optic cable using bi-directional analysis traces with an optical time-domain reflectometer ('OTDR'). Analysis of bi-directional traces along a length of fiber-optic cable yields a scaled local backscatter coefficient of the fiber. Accordingly, an initial set of measurement data is collected at a first time interval and a base scaled local backscatter along a fiber is calculated. A subsequent set of measurement data is collected at a second time interval and a subsequent scaled local backscatter along the fiber is calculated. The exemplary systems and methods described herein determines a change in scaled local backscatter as a function of a difference between the base scaled local backscatter and at least the subsequent scaled local scaled local backscatter along the fiber, and then determines a relative temperature variation of the fiber as a function of the change in scaled local backscatter.

System and method for measuring fiber temperature using OTDR measurements

Described herein are systems and methods for uniquely identifying, or 'fingerprinting,' optical fibers based upon hi-resolution measurements of the backscattered light. One embodiment of the disclosure of this application is related to a computer readable storage medium including a set of instructions that are executable by a processor. The set of instructions being operable to retrieve a profile for an intended fiber, the profile including unique measurement data of the intended fiber, receive from an optical frequency-domain reflectometer further measurement data from a connected fiber within a network, compare the unique measurement data of the intended fiber to the further measurement data of the connected fiber, and confirm an identity of the connected fiber as being the intended fiber when the unique measurement data matches the further measurement data, and trigger an alert when the unique measurement data does not match the further measurement data.

Fiber identification using optical frequency-domain reflectometer

Described herein are systems and methods for uniquely identifying, or 'fingerprinting,' optical fibers based upon measurements from an optical time-domain reflectometer ('OTDR'). One embodiment of the disclosure of this application is related to a computer readable storage medium including a set of instructions that are executable by a processor. The set of instructions being operable to retrieve a profile for an intended fiber, the profile including unique measurement data of the intended fiber, collect further measurement data from a connected fiber within a network, compare the unique measurement data of the intended fiber to the further measurement data of the connected fiber, and confirm an identity of the connected fiber as being the intended fiber when the unique measurement data matches the further measurement data, and trigger an alert when the unique measurement data does not match the further measurement data.

Fiber identification using mode field diameter profile

Described herein are systems and methods for calculating a relative temperature of a fiber-optic cable using bi-directional analysis traces with an optical time-domain reflectometer ('OTDR'). Analysis of bi-directional traces along a length of fiber-optic cable yields a scaled local backscatter coefficient of the fiber. Accordingly, an initial set of measurement data is collected at a first time interval and a base scaled local backscatter along a fiber is calculated. A subsequent set of measurement data is collected at a second time interval and a subsequent scaled local backscatter along the fiber is calculated. The exemplary systems and methods described herein determines a change in scaled local backscatter as a function of a difference between the base scaled local backscatter and at least the subsequent scaled local scaled local backscatter along the fiber, and then determines a relative temperature variation of the fiber as a function of the change in scaled local backscatter.

System and method for measuring fiber temperatures using OTDR measurements

Described herein are systems and methods for enhancing sensitivity of an optical time-domain reflectometer ('OTDR') using bi-directional analysis techniques. One embodiment of the disclosure of this application is related to a computer readable storage medium including a set of instructions that are executable by a processor. The set of instructions being operable to collect a first set of measurement data at a first resolution to provide a relative backscatter of the fiber, collect a second set of measurement data taken at a second resolution to calculate loss along the length of fiber, and combine the first set of measurement data with the second set of measurement data to calculate the loss along the fiber at the first resolution.

Enhanced OTDR sensitivity by utilizing mode-field diameter measurements

Described herein are systems and methods for enhancing the resolution of an optical time-domain reflectometer ('OTDR'). One embodiment of the disclosure of this application is related to a device, comprising an optical measuring component collecting a first set of measurement data from a forward trace along an optical fiber with the optical measuring device using depolarized light, and a processing component calculating loss along the length of fiber. The optical measuring device further collects a second set of measurement data from a backward trace along the optical fiber with the optical measuring device using depolarized light.

Enhanced optical time-domain reflectometer resolution using depolarization of light source

Methods and systems for PMD compensation in an optical communication system are implemented by transmitting multiple optical signals through a common optical conduit to an optical compensator that adjustably rotates the polarization states of the multiple optical signals and transmits the rotated optical signals to an optical receiver. The receiver, upon sensing an excessive error condition, commands the optical compensator to change the polarization state of rotation, which changes the PMD profile of the received optical signals.

Polarization mode dispersion compensation

A method and apparatus is provided for obtaining status information from a given location along an optical transmission path. The method begins by generating a cw probe signal having a prescribed frequency that is swept over a prescribed frequency range. The cw probe signal is transmitted over the optical path and a returned COTDR signal in which status information concerning the optical path is embodied is received over the optical path. A receiving frequency within the prescribed frequency range of the returned COTDR signal is detected to obtain the status information. The detecting step includes the step of sweeping the receiving frequency at a rate equal to that of the prescribed frequency. A period associated with the receiving frequency is temporally offset from a period associated with the prescribed frequency.

COTDR arrangement with swept frequency pulse generator for an optical transmission system

Methods and systems for higher-order PMD compensation are implemented by developing an effective mathematical model and applying economical design techniques to the model. By assuming a constant precession rate for a narrow band of frequencies in an optical signal, a simplified model of a higher-order PMD compensator can be derived. The model can be used produce an economical compensator by making multiple uses of selected optical components.

Methods and systems for polarization mode dispersion compensation

A method is provided for locating a fault in one or more optical amplifiers operating in saturation and located along an optical transmission path. The method begins by generating a coherent optical time domain reflectometry (COTDR) trace representing a backscattered and/or reflected optical power level along the transmission path and comparing the trace to a reference trace to generate a difference trace that represents a change in gain. The change in gain is assigned to at least one of the optical amplifiers based on the difference trace. The method comprises assigning the difference trace to faults in the optical amplifiers, equating the difference trace with a linear combination of difference trace vectors each arising from a fault in a different one of the optical amplifiers, and iterating to determine a coefficient value associated with each difference trace vector. Each nonzero coefficient value denotes a fault in an optical amplifier.

Method and apparatus for obtaining status information concerning optical amplifiers located along an undersea optical transmission line using COTDR

A system, amplifier and method are provided for amplifying an optical signal in an optical communications system where spans between amplifiers may vary. The system includes a Raman amplifier variable gain portion and an EDFA gain portion. The amount of Raman amplifier gain is chosen to trade off accumulation of noise with accumulation of multi-path interference. This variable Raman gain is used to equalize the loss of each span so that the amount of optical power supplied at the input of the EDFA gain portion is substantially constant throughout the system.

Raman assisted EDFA system and method

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Freehold, NJ, United States of America

Jonathan A Nagel