Abstract: 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.

Abstract: 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.

Abstract: An all-optical time slot interchange device comprises at least two wavelength selective delay lines disposed in series and each comprising a delay line for delaying the propagation of an optical signal by increasing the length of the optical path it travels. An optical signal at a given wavelength is extracted from a guide structure and re-injected into the guide structure via the delay line so as to apply a time-delay to the optical signal at a given wavelength. Applications include wavelength-division multiplexing optical telecommunication systems.

Abstract: 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.

Abstract: A high capacity data communication network based on a parallel architecture, linking the nodes of the network itself, having a plurality of logic communication media, wherein for each communication medium a different node of the network is primarily either advantaged or at a disadvantage. As a result, the fairness of the traffic handling is assured independently of the type of protocol used.

Abstract: This subscriber access unit includes an electronic subscriber line interface circuit (1) whose functions include: cell header translation, routing label addition and bit rate control (policing). It further includes concentrators (2) including electronic statistical time-division multiplexing devices (34.1, . . . , 34.16) and electronic periodic time-division demultiplexing devices (47.1, . . . , 47.16) and a photonic wavelength-division multiplexing and bit rate changing device (38), a photonic periodic time-division multiplexing without wavelength-division multiplexing device (40), a photonic bit rate conversion and wavelength-division demultiplexing device (43) and a photonic periodic time-division demultiplexing and wavelength-division multiplexing device (41). This structure optimizes use of photonic technology and electronic technology to achieve a minimal implementation cost.

Abstract: In an optical frequency marking method and a frequency channel communication network using this method, an optical reference frequency is scanned across a scanning band to produce frequency coincidences with a monitored frequency which constitutes the frequency to be marked. During each scanning half-cycle it effects a go path and a return path according to a known law to produce a go frequency coincidence and a return frequency coincidence. A marker interval is measured which is the time elapsed between said two coincidences. This interval marks the monitored frequency and enables said frequency to be locked by comparison with a set point interval. The invention finds a particular application in the marking and stabilization of carrier frequencies of a closely-spaced different frequency channel network.

Abstract: 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).

Abstract: According to the invention, messages to be transmitted between user terminals interconnected by a transmission network are classified into "heavyweight" messages and "lightweight" messages. The heavyweight messages, i.e. messages containing a large quantity of data, are transmitted over the network in message frequency channels attributed to respective heavyweight messages, while the lightweight messages are transmitted over a shared channel common to the lightweight messages.

Abstract: 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.

Abstract: 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.

Abstract: In a method of the invention an emission wave (F(2P-1)) which is to be positioned within the spectrum relative to an external wave (F(2P-2)B) is modulated. Said external wave is mixed with one of the side waves that results from said modulation (F(2P-1)A) and the emission wave is positioned in response to variations in the frequency of a beat signal (F(2P-2)BE) that results from said mixing. The invention applies in particular to implementing an optical fiber communications network.

Abstract: 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.

Abstract: The emission frequencies (F(1) . . . F(2P)) used for simultaneous communications form a stack extending from a fixed based frequency (F(0)) to a top of stack frequency (F(2P-1), F(2-P)). At the beginning of each call, the emission frequency (F(2P-1)) used for the call is at the top of the stack. During the call, said emission frequency is maintained by being servo-controlled to a predetermined spectrum distance (DF) beyond a lower support frequency (F(2P-2)) providing such a frequency can be detected. When such a frequency cannot be detected, the emission frequency is shifted progressively towards the base frequency. The invention is particularly applicable to communications between the peripherals of computer systems.

Abstract: A photodiode (26) receives an optical input signal (P1) and an internal optical signal (P2) and supplies in response thereto an internal electrical signal (I2), which in turn controls a laser (4) which effects amplification and supplies the internal optical signal and an output signal (P3). The feedback loop formed by this photodiode and laser leads to a strong non-linearity in the variation of the output signal as a function of the input signal. The invention is useful especially in optical fiber telecommunications systems.

Abstract: An optical fiber for frequency conversion, has an annular index profile structure for obtaining zero order phase matching and optimum overlap between the fibers's resonant propagation modes, one propagating the wave w and the other the wave kw where 2.ltoreq.k.ltoreq.4 for at least one wavelength lying in the range 0.4 .mu.m to 2.6 .mu.m, with the index step .delta.n in the ring lying in the range 2.times.10.sup.-2 and 5.times.10.sup.-2, the inside radius r.sub.i of the ring lying in the range 0.5 .mu.m to 1.5 .mu.m, and the outside radius r.sub.e of the ring lying in the range 2 .mu.m to 3.5 .mu.m.

Abstract: 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.

Abstract: The system comprises subscriber stations (1, 2) each comprising a semiconductor laser generator (4) provided with means (3, 5) for modulating its laser output by means of transmit signals and a heterodyned detection system consisting of a photoelectric receiver (15) optically coupled to a local oscillator (17), an exchange (32) comprising a computer (37) and dual cavity semiconductor laser transmitters (39) connected to the outputs (38) of the computer, a passive optical distributor (31), and optical fibers (16, 8) connecting the lasers (4) and receivers (15) of each station with the optical distributor (31), on the one hand, and the lasers (4) of each station to the exchange (32), on the other hand, the computer assigning an optical frequency for each requested call and the laser transmitters of the exchange being operable to lock the transmit optical frequency of the calling and the called station lasers (4, 104), via optical fiber lines (8), on the frequency assigned by the computer.