Alcatel

Alcatel Lucent

Draka Comteo B.v.

Nokia Solutions and Networks Oy

Sébastien Bigo

Pierre Sansonetti

Gabriel Charlet

Christian Simonneau

Bogdan Uscumlic

Jeremie Renaudier

Wilfried Idler

Francesco Vacondio

Yann Frignac

Eugen Lach

Petros Ramantanis

Jean-Christophe Antona

Yvan Pointurier

Eric Barnasson

Adrian Voicila

Cyril Ruilier

José Chesnoy

Emmanuel Seve

Simone Musetti

Nicola Rossi

Fabien Boitier

Jérémie Renaudier

The present document relates to a method and apparatus in optical transmission systems for the estimation of the carrier phase and the degree of non-linear distortions incurred in an optical transmission channel. A plurality of signal samples are provided at succeeding time instances such that the plurality of signal samples: is associated with a modulation scheme and a carrier phase; has been transmitted over the optical transmission channel; comprises a plurality of signal phases, respectively; comprises a plurality of data phases and a plurality of residual phases, respectively; and the plurality of residual phases is associated with the carrier phase. The method comprises further canceling the plurality of data phases from the plurality of signal phases by taking into account the modulation scheme; thereby yielding the plurality of residual phases; and determining a set of autocorrelation values of the plurality of residual phases for a set of lag values, respectively.

Carrier phase estimator for non-linear impairment monitoring and mitigation in coherent optical systems

A method for modulating an optical signal includes the following steps: modulating the intensity of the optical signal with a nonreturn-to-zero bit signal, and modulating the phase of the optical signal with a periodic phase-shift signal creating an alternating &#x3c0;-phase shift every second, third or more consecutive bit. An optical transmitter for performing the above method comprises a first modulator () modulating the intensity of the optical signal with a nonreturn-to-zero bit signal, and a second modulator () modulating the phase of the optical signal with a periodic phase-shift signal creating an alternating &#x3c0;-phase shift every second, third or more consecutive bit.

Method for modulating an optical signal and optical transmitter

The invention shows a transmission system with a transmitter function, a transmitting fiber and a receiver function where the transmitter function comprising lightsources (), modulators () and a multiplexer (), and the receiver comprising at least a demultiplexer (), filters and electrical receivers where the channels for left side filtering are modulated with modulators with a negative chirp and for right side filtering with modulators with positive chirp.

Modulation scheme and transmission system for NRZ signals with left and right side filtering

The present invention specially deals with a transmission system in which at least two coded optical signals are multiplexed and transmitted between an emitter and a receiver, a first of said coded signals providing a first spectrum having a first carrier wavelength and two side-bands, a second of said coded signals providing a second spectrum having a second carrier wavelength higher than said first carrier wavelength and two side-bands. This transmission system comprises at least one optical filter with to combined filters for the carrier wavelength and the respective sideband.

Optical filter and transmission system incorporating an optical filter

The present invention propose an optical filter for filtering out at least a part of one of two spectral side-bands of a coded optical signal spectrum having a carrier wavelength, the first of said side-bands which is to be transmitted by said filter being called transmitted side-band, the second of said side-bands which is to be filtered out by said filter being called vestigial side-band, said optical filter having a transmission response in intensity, having a maximum value at a central filter wavelength distinct from said carrier wavelength and located in said transmitted side-band, and said response being divided into two parts, a first filter part associated to a wavelength region including said carrier wavelength, a second filter part associated to a wavelength region which does not include said carrier wavelength where at a given value of transmittance distinct from said maximum value, said second filter part has a filter width smaller than the filter width of said first filter part.

The fiber is adapted to compensation of the chromatic dispersion and chromatic dispersion slope of an optical fiber with negative chromatic dispersion. It has, in a propagation mode other than the fundamental mode, a positive chromatic dispersion and a negative chromatic dispersion slope. The fiber can be used in compensation dispersion modules or as line fiber, in transmission systems using line fiber with negative chromatic dispersion.

Fibre for compensation of the cumulative chromatic dispersion in a fibre with negative chromatic dispersion

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Massy, France

Sébastien Bigo