Alcatel Cit

Alcatel N.v.

Societe Anonyme Dite: Alcatel Cit

Guy Le Roy

Jean-Michel Gabriagues

Jean-Baptiste Jacob

Michel Sotom

Amaury Jourdan

Christian Duchet

Jean-Claude Jacquinot

Muguette Fraise

Selection switches (C1, . . . , C3-4) enable an optical path (BC, C1, C2-1, C3-1, D1, B1) to be selected from a plurality of such paths predefined on a common substrate (PE), each of the switches belonging to a plurality of such paths for that purpose. Isolation switches (D1, . . . , DN) each belong to one such path only. The isolation switches are disposed at the ends of the paths so as to enable the selected path to be isolated from optical members (LEN) that are outside the selector and that are connected to the non-selected paths. In this way crosstalk is avoided. The invention applies in particular to backing up an optical link.

Optical selector and an optical link including the selector

Optical transmission network with a switching matrix

An optical wavelength converter has an optical signal input adapted to receive an optical signal whose wavelength is to be converted, an optical signal output adapted to emit an optical signal whose wavelength is the required wavelength, after conversion, and at least one control electrode for applying at least one electrical signal to control the wavelength of the output optical signal. The converter is controlled by a method which comprises a calibration phase for establishing a law linking at least one of said control electrical signals to said required output wavelength and storing said law in a storage device, and an operative phase for addressing said storage device using the required output wavelength and numerical-analog conversion of the data from the storage device addressed in this way for application to said control electrode(s).

Optical wavelength converter control method and device

A photonic concentrator is used to connect to a telecommunication network subscriber terminals sending and receiving data in the form of fixed length cells using asynchronous time-division multiplexing, in particular on an optical fiber. The concentrator comprises, for processing cells from a subscriber terminal, a time-division and non-synchronous statistical spectral multiplexing stage, a synchronization to a local clock stage, a spectral multiplexing and bit rate converter stage, and a periodic time-division multiplexing stage. To process cells addressed to subscriber terminals it comprises a periodic time-division demultiplexing, spectral multiplexing and bit rate adjuster stage, a bit rate converter stage and a spectral demultiplexing stage. The concentrator has applications in telecommunication networks.

Photonic concentrator

A multiplexer and a demultiplexer time-division multiplex and demultiplex binary data in the form of cells having a fixed number of bits. For example, to time-division multiplex cells comprising 424 bits the original bit rate of a block of 16 bits of a cell is multiplied by four, each cell being divided into a series of 27 blocks. The blocks constituting each cell are concatenated after their bit rate has been multiplied. Similarly, the demultiplexer divides the bit rate by dividing each cell into blocks, separating consecutive blocks by a gap and dividing the bit rate successively in each block. The multiplexer and demultiplexer have applications in time-division multiplex telecommunication networks.

Photonic time-division multiplexer and demultiplexer

A photonic switching matrix comprises a plurality of wavelength converters at respective inputs of the matrix to assign a wavelength to each cell applied to an input of the matrix. An optical buffer common to all the outputs of the matrix stores each cell for a duration selectable between 0 and k.T.sub.c where k is an integer and T.sub.c is the duration of cell. A space routing stage comprises a filter for each output of the matrix passing to a given output only cells having a given wavelength. The converters and the buffer are controlled according to routing information indicating for each cell the output of the matrix to which said cell is addressed and for selecting the duration for which each cell is stored in the buffer so as to construct a queue for each output to avoid conflicts between two cells to be switched to the same output presented at the same time as the input of the switching matrix. The switching matrix has applications in telecommunication networks.

Photonic switching matrix

An asynchronous time-division multiplex optical communication system comprises: a switching network, user transmitter circuits, user receiver circuits and broadcast servers connected by optical lines to the switching network. The switching network comprises an optical spectro-time-division switching network, a control processor unit and a clock unit. The spectro-time-division switching network is connected optically to the user transmitter circuits, to the user receiver circuits, to the broadcast servers and to control transmitter, signalling transmitter, control receiver and signalling receiver circuits of the control processor unit. The clock unit is connected by a first line to the switching network and by a second line to the control processor unit which is connected by a control bus to the spectro-time-division switching network. The system uses conjointly a first set of optical frequencies for transmission and a second set optical frequencies for switching.

Asynchronous optical communication system

The connection system includes at least one connection assembly having at least one connection module with a connection capacity of N optical lines. A connection module comprises first, second, and third optical switch assemblies (C11 to C1n, C21 to C2n, and C31, C32). The first assembly is connected to the N optical lines, the second assembly is connected firstly to the first assembly and secondly to the junctors and the spare junctors associated with the N optical lines, and the third assembly is connected firstly to the first assembly and secondly to at least one test circuit via a line test optical fiber and via a junctor test optical fiber. When using narrowband optical switches, there are two switching assemblies, one for transmission and the other for reception of the signals conveyed by the optical lines, when using wideband optical switches, then a single switching assembly is used both for transmission and for reception, i.e. for both call directions.

System for connecting optical lines to a wideband telecommunications

The diffuser is made from N=2.sup.n light ducts divided into two sets of 1/2N ducts, with every other duct belonging to a different one of the sets. The two sets of ducts are helically wound in opposite directions but at the same helical pitch over a cylinder (1). Each duct in either set crosses over the 1/2N ducts in the other set, and couplers are provided at those cross-overs between any given duct and the 1/2N ducts of the other set having cross-over numbers 2.sup.q, where q=0, 1, 2, . . . , (n-1). The diffuser has stages each comprising 1/2N couplers, with each stage being disposed in a ring around the cylinder.

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Lannion, France

Guy Le Roy