Alcatel

Alcatel N.v.

Alcatel Alsthom Compagnie Generale D'electricite

Dominique De Bouard

Michel Sotom

Dominique Chiaroni

Corinne Chauzat

Jean-Michel Gabriagues

Francesco Masetti

A switch which avoids imparting interference noise, limiting communications speed, and imparting losses, includes n passive couplers, each of which is provided with a number k of outlets, and with an inlet suitable for receiving one input signal; and k wavelength multiplexers, each of which is provided with n inlets set to respective ones of n wavelengths. For each multiplexer, that one of its inlets which is set to one of the wavelengths, is coupled via an amplifying optical gate to one of the outlets of that one of the couplers that is organized to receive an input signal carried by the same wavelength. The switch is used in performing routing functions in communications networks having optical links.

Optical switch

In packet time-division multiplexing communications systems using optical networks, an optical method and circuits used in electrical-to-optical conversion interfaces assure that data rates of the electrical domain match the data rates of the optical domain. An optical method of concatenating binary information contained in successive time windows of an input signal includes forming g converted input signals obtained by amplitude modulating g optical carrier waves having different wavelengths, each converted input signal presenting, within the time windows, amplitude modulation as a function of the input signal. The method also includes forming a multiplex signal made up of a combination of g delayed signals obtained by applying delays to the converted input signals, the delays being such that any two consecutive delayed signals are offset in time by the duration w of the time windows.

Method and a circuit for concatenating binary information, and use in optical packet transmission

In communications systems having optical networks, data rates in the electrical domain can be matched to data rates in the optical domain by means of time-division multiplexing, with the pulses forming the transmitted optical data being compressed. A method performs the necessary pulse decompression on reception in all-optical manner. The method includes forming q auxiliary signals respectively obtained by amplitude modulating each of q optical carrier waves having different wavelengths by the received signal, and superposing q delayed auxiliary signals obtained by applying delays to the auxiliary signals such that any two consecutive delayed auxiliary signals are offset in time by the duration of the pulses making up the received signal.

Method and apparatus for decompressing pulses making up a binary optical signal

In order to re-synchronize and shape a binary signal of bit time T0, a method includes forming a number p of sampled signals obtained by causing the signal to modulate pulses that are of frequency 1/T0 and of duration substantially equal to T0/p, and that are carried by p optical carriers having different wavelengths. The method also includes combining delayed signals that are obtained by applying delays to the sampled signals, such that any two consecutive delayed signals are offset in time by T0/p. The method applies to optical communications systems.

Method and apparatus for shaping a binary signal

In order to reduce its switching time, the delay apparatus comprises a coupler and a multiplexer provided with n inlets set respectively to n distinct wavelengths. Inlets of the multiplexer are coupled respectively to outlets of the coupler via wavelength conversion apparatuses, and via delay lines all of which are different. Each conversion apparatus has an amplifying optical gate function and delivers to the corresponding inlet of the multiplexer a wave carried by the wavelength associated with said inlet. The invention also concerns apparatus for synchronizing channels of a wavelength multiplex using the variable delay apparatus. Application in particular to synchronizing optical packets in a switched optical network.

Variable delay apparatus for optical signals

To simplify the connection protocols of an optical communication network using wavelength division multiplexing and to increase the throughput of the network, each node sends messages on a specific wavelength and associates destination labels with them. A network controller receives the messages and the labels and forwards the messages on the receive wavelength of their destination node(s). Applications include local area networks.

Wavelength division multiplexing optical communication network

To shape binary optical signals, the apparatus comprises a first stage for providing a modulating signal whose high levels are stabilized so as to depend little on fluctuations in the input signal. The signal is applied to a second stage including an interferometer structure designed to deliver an output signal that is the result of interference between first and second auxiliary waves, the interference being respectively constructive and destructive when the power of the modulating signal corresponds respectively to a first logic state and to a second logic state. The apparatus can be used to modify the input signal by deleting or inserting data. It can be used in optical data switching or transmission.

Apparatus for shaping binary optical signals, and use thereof to modify

Logic operations are carried out on binary optical signals using a non-linear optical amplifier having a front port and a rear port respectively receiving a front wave and a modulated rear wave. The output wave via the rear port is separated from the rear wave by exploiting the fact that they have opposite propagation directions. Applications include optical data switching and transmission.

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Ste Genevieve des Bois, France

Dominique De Bouard