Tyco Telecommunications (us) Inc.

Tyco Submarine Systems Ltd.

At&t Bell Laboratories

At+t Corp.

Tycom (us) Inc.

Subcom, LLC

Tyco Electronics Subsea Communications LLC

Neal S Bergano

Alexei N Pilipetskii

Carl R Davidson

M Imran Hayee

Stephen G Evangelides, Jr

Vincent J Mazurczyk

Paul Francis Wysocki

Morten Nissov

John L Zyskind

Bo Pedersen

Georg Heinrich Mohs

Dmitri G Foursa

Franklin Webb Kerfoot, Iii

Hussam G Batshon

Jin-Xing Cai

Oleg V Sinkin

Linn F Mollenauer

Kwang S Kim

James W Sulhoff

Ekaterina A Golovchenko

Stuart M Abbott

George T Harvey

Chinlon Lin

Cleo D Anderson

Xiaobing Ma

Richard G Smart

Patrick Ross Trischitta

Richard L Maybach

William W Patterson

Bruce M Nyman

Carl Davidson

Richard F Druckenmiller

Jennifer Aspell

A novel system and apparatus for detecting and locating an external aggression on at least one optical cable of an optical communication system is provided. For example, a signal from a transmitter may be received and analysis may be performed to recover a state-of-polarization (SOP) associated with the signal. A first rapid polarization change that occurs may be identified, which may indicate that an external aggression has occurred on the at least one optical cable. A time offset between the first rapid polarization change and a second rapid polarization change may be used to estimate a location of the external aggression.

System and apparatus for detecting and locating external aggression on an undersea cable

This spatial division multiplexing (SDM) in power-limited optical communication systems. In general, an SDM optical transmission system may be configured to increase data capacity over the data capacity of a non-SDM optical transmission system while maintaining power consumption at or below that of the existing non-SDM optical transmission system. To realize such an improvement in performance without increasing power consumption, an example SDM optical transmission may be constructed by reducing system bandwidth, reducing and/or altering equipment for filtering, reducing optical amplifier spacing, reducing operational amplifier power consumption, etc. In this manner, increased data transmission performance may be realized even where available power may be strictly limited.

Spatial division multiplexing in limited power optical communication systems

A WDM optical transmission system and method uses slope compensation at the transmit terminal and/or the receive terminal. The system and method may be used with modulation formats with a short pulse width and a broad optical spectrum.

Optical transmission system including dispersion slope compensation

An optical communication system configured to operate with optical signals at lower signal to noise ratios than previously contemplated. The communication system includes a receiver having an optical pre-processor coupled between a demultiplexer and a detector. The optical pre-processor includes either an optical polarization section having a polarization rotator and an optical polarizer, a phase modulation section that includes a phase modulator and a dispersion element and a clock recovery circuit, or an amplitude modulation section that includes an amplitude modulator clock recovery circuit and a spectral shaping filter. A method of communication includes transmitting an optical signal into the system and receiving the signal at a reduced signal-to-noise ratio through a transmission media, demultiplexing the optical transmission signal into a first optical signal, and pre-processing the first optical signal to form a first pre-processed signal by either rotating a polarization of the first optical signal, compressing a pulse in the first optical signal, or modulating an amplitude of a pulse in the first optical signal. The method then detects the first pre-processed signal to form an electrical signal. A reference signal-to-noise ratio is defined as a signal-to-noise ratio of a received signal that would produce a predetermined bit error rate in the electrical signal if the signal-to-noise ratio were to be determined with the pre-processing step omitted. The reduced signal-to-noise ratio is less than the reference signal-to-noise ratio, and a bit error rate in the electrical signal is less than the predetermined bit error rate when the step of transmitting transmits at the reduced signal-to-noise ratio.

Optical transmission system using optical signal processing in terminals for improved system performance

A method and apparatus is provided that yields improved performance of both single channel and WDM long-distance optical transmission systems by synchronously modulating of the transmitted signal's amplitude. An amplitude modulator receives an optical signal onto which data has been modulated at a predetermined frequency. The modulator re-modulates the amplitude of the optical signal in a continuous fashion with a waveform that is periodic, whose fundamental frequency is equal to the same predetermined frequency at which the data is modulated onto the optical signal. The resulting signal (which is neither a pure NRZ or RZ signal) is more tolerant to the distortions usually found in lightwave transmission systems, thus giving superior transmission performance.

Synchronous amplitude modulation for improved performance of optical transmission systems

The position and amount of localized polarization dependent anomalies such as polarization mode dispersion and/or polarization dependent loss may be measured by applying a polarization modulated probe signal to an optical transmission line. The polarization modulated probe signal is returned via optical feedback paths positioned along the line, and is detected by a probe signal receiver to identify the position and strength of the anomaly.

Method and apparatus for detecting localized polarization dependent anomalies on optical transmission lines

A method and apparatus is provided that yields improved performance of both single channel and WDM long-distance optical transmission systems by synchronously modulating of the transmitted signal's amplitude. An amplitude modulator receives an optical signal onto which data has been modulated at a predetermined frequency. The modulator re-modulates the amplitude of the optical signal in a continues fashion with a waveform that is periodic, whose fundamental frequency is equal to the same predetermined frequency at which the data is modulated onto the optical signal. The resulting signal (which is neither a pure NRZ or RZ signal) is more tolerant to the distortions usually found in lightwave transmission systems, thus giving superior transmission performance.

An apparatus comprises operationally coupled optical fiber segments that define an optical sublink. The optical sublink has link spans including a first link span and a second link span. The first link span has an average dispersion with a magnitude greater than zero. The second link span has an average dispersion with a magnitude greater than zero. The optical sublink has an end-to-end dispersion less than an end-to-end dispersion tolerance limit.

Method and apparatus for the optimization of dispersion map using slope-compensating optical fibers

A WDM optical communication system is provided that includes a transmitter and a receiver. An optical fiber transmission path couples the transmitter to the receiver. The transmission path includes at least one repeater having an optical amplifier located therein. A dispersion compensator is disposed at an intermediate point along the transmission path. The intermediate point is located outside of the repeater. The compensator includes a wavelength routing device for dividing a signal having a prescribed bandwidth into a plurality of distinct sub-bands. A plurality of output paths is provided for respectively receiving the plurality of distinct sub-bands. The dispersion compensator also includes a dispersion compensating optical element coupled to each of the output paths. Each dispersion compensating optical element substantially compensates for dispersion at a prescribed wavelength within the bandpass of its respective sub-band. A coupler recombining the distinct sub-bands and couples them back onto the optical fiber transmission path.

Method and apparatus for providing chromatic dispersion compensation in a wavelength division multiplexed optical transmission system

A method and apparatus is provided for transmitting an optical signal having a total number of channels that are dividable into a prescribed number of wavebands. The method includes the step of generating a first series of optical signals corresponding to each of the wavebands. The first series of optical signals includes a plurality of optical channels, which are sequentially numbered from 1 to N from lowest to highest wavelength. Within each waveband, a state-of-polarization of predetermined odd-numbered channels is oriented to be substantially orthogonal to a state of polarization of predetermined even-numbered channels by directing the predetermined odd-numbered channels and the predetermined even-numbered channels through orthogonally polarizing inputs of a polarization coupler. The odd-numbered channels and the even-numbered channels within each waveband may be directed through first and second wavelength combiners, respectively, prior to orienting their states of polarization. The orthogonal relationship between the states of polarization of odd and even-numbered channels within each waveband advantageously limits the four-wave mixing products that can be generated in the optical transmitter and the optical transmission path to which it is typically coupled.

Method and apparatus for transmitting a WDM optical signal having states of polarization that are pairwise orthogonal

A method and apparatus is provided for transmitting an optical signal. The method includes the step of generating an optical signal that includes a plurality of optical channels, which are sequentially numbered from 1 to N from lowest to highest wavelength. Dispersion compensation is imparted to each of the plurality of optical channels without a change in polarization of the channels. A state-of-polarization of predetermined odd-numbered channels is oriented to be substantially orthogonal to a state of polarization of predetermined even-numbered channels by directing the predetermined odd-numbered channels and the predetermined even-numbered channels through orthogonally polarizing inputs of a polarization coupler. The odd-numbered channels and the even-numbered channels may be directed through first and second wavelength combiners, respectively, prior to orienting their states of polarization. The orthogonal relationship between the states of polarization of odd and even-numbered channels advantageously limits the four-wave mixing products that can be generated in the optical transmitter and the optical transmission path to which it is typically coupled.

Method and apparatus for performing dispersion compensation without a change in polarization and a transmitter incorporating same

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Lincroft, NJ, United States of America

Neal S Bergano