At+t Corp.

At&t Intellectual Property I, LP

Tel Aviv University

Antonio Mecozzi

Mark Shtaif

Jonathan A Nagel

Moshe Tur

Cristian Antonelli

Alan H Gnauck

Jay Martin Wiesenfeld

Peter David Magill

Mikhail Brodsky

Mikhail Boroditsky

Carl Balslev Clausen

Ronen Dar

Meir Feder

There is provided a Kramers-Kronig receiver, comprising a reception path; wherein the reception path comprises: a Stokes receiver that is configured to receive a polarization-multiplexed signal and to output a Stokes vector; wherein the polarization-multiplexed signal comprises a first modulated signal, a second modulated signal and a continuous wave signal; wherein the first modulated signal is of a first polarization; wherein the second modulated signal is of a second polarization; wherein the continuous wave signal is of the first modulation or of the second modulation; a set of analog to digital converters that are configured to generate a digital representation of the Stokes vector; and a digital processor that is configured to process the digital representation of the Stokes vector to provide a reconstructed polarization-multiplexed signal, wherein the processing is based on a Kramers-Kronig relationship related to the polarization-multiplexed signal.

Kramers-Kronig receiver

A Kramers-Kronig receiver that may include a reception path; wherein the reception path may include a photodiode that is configured to receive a received signal and output a photocurrent that represents the received signal; wherein the received signal comprises a continuous wave (CW) signal and a modulated signal; wherein a frequency gap between the CW signal and the modulated signal is smaller than a bandwidth of the modulated signal; an analog to digital converter that is configured to generate a digital representation of the photocurrent; and a digital processor that is configured to process the digital representation of the photocurrent to provide a reconstructed modulated signal, wherein the processing is based on a Kramers-Kronig relationship related to the received signal.

A method that may include receiving a block of signals from a certain wavelength division multiplex (WDM) channel out of a set of WDM channels; analyzing at least a first sub-block of signals of the block of signals to provide analysis results indicative of interferences that affect the first sub-block of signals and result from transmissions over other WDM channels of the set of WDM channels; and mitigating interferences that affect the block of signals in response to the analysis results.

Nonlinear noise cancellation in wavelength division multiplexing (WDM) systems

Disclosed is a method and apparatus for determining the birefringence autocorrelation length of a fiber in a non-destructive manner. The PMD of an optical fiber is measured over a first optical spectrum. A Faraday rotation angle is measured over a second optical spectrum. The birefringence autocorrelation length is determined from the measuring of the PMD and the Faraday rotation angle.

Method and apparatus for measuring the birefringence autocorrelation length in optical fibers

A system and method for increasing transmission distance and/or transmission data rates using tedons and an encoding scheme to reduce the number of ones in a data signal is described. For example, the method for increasing transmission distance and transmission data rate of a fiber optical communications link using tedons includes the steps of encoding a data signal to be transmitted using an encoding scheme that reduces a number of ones in the data signal, transmitting the encoded data signal over the fiber optical communications link, receiving the encoded data signal and decoding the encoded data signal.

Modulation scheme for tedons

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 system and method for increasing transmission distance and/or transmission data rates using tedons and an encoding scheme to reduce the number of ones in a data signal is described. For example, the method for increasing transmission distance and transmission data rate of a fiber optical communications link using tedons comprises the steps of encoding a data signal to be transmitted using an encoding scheme that reduces a number of ones in the data signal, transmitting the encoded data signal over the fiber optical communications link, receiving the encoded data signal and decoding the encoded data signal.

A system and method for reducing timing and amplitude jitter in trnasmission of Retrun-to-Zero modulated pulses is described. In the reduction of amplitude jitter the modulated pulses must be phase coherent. The method comprises the steps of measuring a total dispersion of a transmission fiber link, computing an optimal amount of pre-chirp to be added at an input of said transmission fiber link, computing an optimal amount of pre-chirp to be added at an output of said transmission fiber link, adding said optimal amount of pre-chirp to said input of said tranmisssion fiber link and adding said optimal amount of pre-chirp to said output of said tranmisssion fiber link. The system for reducing timing jitter in transmission of Return-to-Zero modulated pulses comprises means for measuring a total dispersion of a transmission fiber link, means for computing an optimal amount of pre-chirp to be added at an input of said transmission fiber link, means for computing an optimal amount of pre-chirp to be added at an output of said transmission fiber link, means for adding said optimal amount of pre-chirp to said input of said transmission fiber link and means for adding said optimal amount of pre-chirp to said output of said transmission fiber link.

Method and system for reducing intra-channel nonlinear effects in highly dispersed optical pulse transmission

A system and-method for reducing timing and amplitude jitter in transmission of Retrun-to-Zero modulated pulses is described. In the reduction of amplitude jitter the modulated pulses must be phase coherent. The method comprises the steps of measuring a total dispersion of a transmission fiber link, computing an optimal amount of pre-chirp to be added at an input of said transmission fiber link, computing an optimal amount of pre-chirp to be added at an output of said transmission fiber link, adding said optimal amount of pre-chirp to said input of said transmission fiber link and adding said optimal amount of pre-chirp to said output of said transmission fiber link. The system for reducing timing jitter in transmission of Return-to-Zero modulated pulses comprises means for measuring a total dispersion of a transmission fiber link, means for computing an optimal amount of pre-chirp to be-added at an input of said transmission fiber link, means for computing an optimal amount of pre-chirp to be added at an output of said transmission fiber link, means for adding said optimal amount of pre-chirp to said input of said transmission fiber link and means for adding said optimal amount of pre-chirp to said output of said transmission fiber link.

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Rome, Italy

Antonio Mecozzi