Alcatel N.v.

Alcatel

Alcatel Lucent

Nokia Solutions and Networks Oy

Alcatel Submarine Networks

Sebastien Bigo

Emmanuel Desurvire

Patrick Brindel

Olivier Leclerc

Francesco Vacondio

Petros Ramantanis

Jean-Christophe Antona

Yvan Pointurier

Christian Dorize

Emmanuel Seve

Guillaume Pierre Fernand Soudais

Nihel Djoher Benzaoui

In certain embodiments, a communication network has a specialized ingress node that converts one or more incoming flows into a single, packetized, time-division multiplexed (TDM) flow; a switch fabric that routes the TDM flow via a fixed path through the switch fabric in a contention-free manner; and a specialized egress node that converts the TDM flow received from the switch fabric into one or more outgoing flows corresponding to the one or more incoming flows. The technology turns legacy, best-effort packet-switching into deterministic circuit-switching for a programmable selection of flows with minimal impact on network dynamics and at relatively low cost.

Deterministic communications via packet-switched networks

A technique is provided for determining an optical transmission system description. The technique includes determining a dispersion map of the optical transmission system, placing a set of discrete cumulative dispersions onto the dispersion map, and defining a plurality of sequential system segments of the optical transmission system. Each system segment has an input point that corresponds to a point in the optical transmission system where the input cumulative dispersion matches a cumulative dispersion of the set of discrete cumulative dispersions. For each system segment, an input power of the system segment and a local dispersion value of the system segment is determined. Also, for each system segment, a sequence number of the system segments is stored. Furthermore, for each system segment, the input power and the local dispersion value determined in relation with the input cumulative dispersion of the system segment in a data repository is stored.

Method for determining an optical transmission system description

In a wavelength-division multiplex fiber optic soliton signal transmission system the wavelengths of the multiplex are chosen to assure a relative slippage between the channels at a given interval substantially equal to a multiple of the bit time. At one point of the transmission system at least, the soliton pulses of the various channels have a temporal offset relative to a given reference such that, on distributed optical modulation by a clock that is input at this point, for each channel, the extremum of the non-linear phase profile induced by the clock, integrated over the modulation length, coincides with the center of the bit time. In a system of this kind distributed optical modulation can be applied to all the channels of the multiplex by a single sinusoidal signal. The modulation can be effected in a non-linear optical loop mirror or in the transmission fiber itself.

Optical regeneration for wavelength-division multiplex soliton signal

In an optical modulation method a wave to be modulated and an optical control wave are injected simultaneously and colinearly into the same waveguide formed in a semiconductor diode that is reverse-biased so that the waveguide and the diode constitute the semiconductor part of an electro-absorption modulator. The wavelength of the control wave is shorter than that of the wave to be modulated. The impedance at the terminals of the diode is sufficiently high to enable amplitude modulation of the control wave to be transferred to the wave to be modulated. Applications include fiber optic telecommunication systems, in particular for resynchronizing solitons.

Modulation method and semiconductor optical modulator

The invention relates to a Kerr type optical modulator and to an all-optical clock recovery circuit operating by active mode locking of a fiber loop laser including such a modulator. Operation is independent of the polarization of the signals presented to the signal input, at wavelength .lambda..sub.s. The wavelength of the clock signal delivered by the clock recovery circuit is .lambda..sub.c. The modulator comprises an even number of segments, and in a preferred embodiment four segments of polarizationmaintaining fiber, with the segments being of equivalent optical lengths, and interconnected by three splices at three locations. At the first and third splices, the neutral propagation axes of the polarization-maintaining fiber are turned through 90.degree.. In an advantageous variant of the invention, a mode converter is inserted in the loop at the second splice, the mode converter comprising an optical demultiplexer and an optical multiplexer together with two polarization-maintaining optical paths interconnecting them. The demultiplexer separates the two different-wavelength optical signals present in the loop of the fiber laser and applies them respectively to said two paths. A splice including 90.degree. rotation of the neutral axes of the polarization-maintaining fibers is made on the path conveying the input signal at wavelength .lambda..sub.s. On the other path, there is no rotation of the axes. The multiplexer then recombines the two signals. The invention is applicable to long distance telecommunications via optical fiber.

Polarization-independent Kerr modulator, and an all-optical clock

The invention relates to an adjustable optical amplitude and phase modulator using a non-linear optical loop mirror having two control inlets and a signal inlet. In a preferred embodiment, a single clock signal is split into two and applied to the two control inlets. The invention also relates to a soliton regenerator including said optical modulator. In an important variant, said modulator receives a soliton bit train on its signal inlet at a bit rate f.sub.s, and on its control inlets it receives a clock signal at half that frequency f.sub.c =f.sub.s /2. In an advantageous embodiment, said clock signal is applied with a phase shift of .pi. between the two control inlets, so as to minimize the effects of collisions between solitons. The invention is applicable to long distance telecommunications by optical fiber.

Adjustable optical amplitude and phase modulator, and a soliton

The invention relates to a non-linear optical mirror comprising an optical fiber loop that operates independently of the polarizations of the signals of respective wavelengths .lambda..sub.s and .lambda..sub.c present on its signal and control inputs. The loop of the NOLM is made up of four polarization-maintaining fiber segments having equivalent optical lengths. These four segments are optically optically interconnected by three splices at three locations. At the first and third splices, the neutral propagation axes of the polarization-maintaining fibers are turned through 90.degree.. According to the invention, a mode converter is inserted in the loop at the second splice, the converter comprising an optical demultiplexer and an optical multiplexer together with two polarization-maintaining optical paths inter-connecting them. The demultiplexer separates the two optical signals present at its input and applies them respectively to said two paths. On the path conveying the control signal, .lambda..sub.c, there is a splice including 90.degree. rotation of the polarization-maintaining neutral axes. On the other path, there is no rotation of the axes. The multiplexer then recombines the two signals. The invention is applicable to long distance telecommunications by optical fiber.

Polarization independent non-linear optical mirror

The apparatus of the invention regenerates solitons in-line by synchronously modulating the solitons using a non-linear optical loop mirror as an optical modulator, the NOLM modulator being controlled by a clock signal recovered from the soliton signal by clock recovery means which may be all-optical means or electro-optical means. The NOLM includes an input coupler which may be a 50/50 coupler or an asymmetrical coupler. Said input coupler may be a 2x2 coupler or a 3x3 coupler. In a particular embodiment, the regenerating system further includes a plurality of optical amplifiers and a plurality of 'guiding' filters. Application to long-distance soliton optical telecommunications.

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Palaiseau, France

Sebastien Bigo