Abstract: An optical crossconnect includes optical elements (D1 . . . DM) for wavelength demultiplexing of optical signals and elements (MT) for optically processing the demultiplexed signals which give each optical signal a specific wavelength and bring to one of the outputs (S1 . . . SM) the signal with the specific wavelength under the control of a management unit (G). Such an optical crossconnect may find particular application in telecommunication networks.

Abstract: The present invention concerns a method for transmitting and switching packets in an optical network embodying a synchronous time-division multiplexing, the packets being transmitted at a given speed and the rate being determined by the line occupation time.The present invention also concerns a device for transmitting and switching packets in an optical network.

Abstract: A process for the transposition of a modulation of an adjustable wavelength. A semiconductor amplifier is relooped through a feedback loop including a filter set to a first wavelength. An incident beam set at a second wavelength which is amplitude modulated is injected into the semiconductor amplifier laser. The incident beam is either extinguished or allows self-oscillation to be established in the loop. Thus, the modulation is transposed from the second wavelength to the first wavelength.

Abstract: Optical communications system using traveling wave semiconductor optical amplifiers has at lest one optical fiber (2), tranceivers, (S1. . . , SN) placed along the fiber and having in each case at least one travelling wave semiconductor optical amplifier (A1. . . , AN), which is located in series with the fiber and transmission means (L1, L2) for feeding into the fiber at least one continuous optical signal. Each amplifier is used alternately to modulate the continuous optical signal in order to transmit information, and to detect information modulations of the optical signal which carry information.

Abstract: An optical device for recovering the timing of a signal (Si) coded by a digital code, such as the NRZ, CMI, biphase or similar code, is provided. The device has a circuit for shaping and transforming the coded signal into the form of a series of pulses of duration equal to T/2 and occurrence equal to N.times.T, and a timing recovery circuit for determining the timing signal. The present invention has particular utility in the area of digital transmission by optical fibers, although other utilities are also contemplated.

Abstract: An interactive optical transmission system including a transmitter assembly (EE) with a FSK DFB laser (10) and a receiver assembly (ER) having the same type of DFB laser (20) and functioning as a photoreceiver. In order to make this system interactive, the receiver (ER) is provided with a channel selection circuit (40) able to supply a current which will place the laser (20) of the receiver assembly (ER) well above the threshold and make it function as an amplitude shift keyed transmitter. The beam transmitted by said laser (20) will raise the optical transmission line (FO) to the transmitter assembly (EE). An amplitude demodulation (48) will make it possible to restore the selection code and control the appropriate information channel (S).

Abstract: A bidirectional transmission system with identical laser components. The system features two identical assemblies. Each assembly is constituted by a laser structure able to operate as either an emitter or as a receiver. The system thus has a half-duplex operation. Such a system finds particular application to optical communications.

Abstract: Logic function generator using an optical transposition in a distributed feedback laser diode. It comprises sources (LD1, LD2) of synchronous digital optical signals having the same rate, an optical coupler (10) receiving said signals and supplying an optical signal, a distributed feedback laser diode (LD3) into which is injected said optical signal, means (24) for the electrical polarization of said laser diode enabling the latter to supply a signal, whose optical frequency varies as a function of the optical power of the injected signal, an optical filter (12) which receives said signal and which is frequency tunable and control means (28) for the said filter. The latter supplies a signal which is a logic function of the signals of the sources. Application to optical calculation.

Abstract: Process for optical transmission by wavelength shifting and corresponding system. According to the invention, a wavelength hop corresponding to a mode hop of the laser is performed. The laser (20) is supplied by two currents, which fix the emission wavelengths (.lambda.1, .lambda.2).

Abstract: A process for optical transmission by self-heterodyning and a transmission system with a switching matrix using the process. The process consists in transmitting optical signals to one or more receivers of N, from optical transmission means including an optical signal emitting device for modulation by frequency transposition, and an optical fiber connection. Also included in the process is the transmission a given signal on one or more carrier frequencies respectively to one or more receivers, the obtaining of the carrier frequency or frequencies by transposition of an emission frequency by one or more modulation frequencies which are distinct and can be selected as a function of the receiver or receivers, and the transmission of the emission frequency signal on the same optical connection.

Abstract: A laser infrared light source is mounted on a mount, a mirror ensuring the mode selection, a photodetector being positioned behind the mirror and connected thereto by an optical fibre and a fibre guiding the useful beam. These element are held by resin supports resting on a base plate.