France Telecom

France Telecom Etablissement Autonome De Droit Public

Minister of the Post Telecommunications and Space (centre National

France Telecom Establissment Autonome De Droit Public

Georges Claveau

Rene Auffret

Mouhammad Jamil Chawki

Patrice Pottier

Francedillaois Tillerot

Mouhamad Chawki

Herve Dupont

Jean Le Bihan

A device for the frequency transposition of optical signals receiving data elements liable to be at different wavelengths (.lambda.0, .lambda.1 . . . .lambda.n) and capable of delivering, at output, these data elements at one of the reception wavelengths. The device comprises a circulator (30); at least one optical arm comprising a rejection filter (31) followed by a wavelength converter (32); the circulator comprising a port for the reception of the data packets at the different wavelengths (.lambda.0, .lambda.1 . . . .lambda.n), a port for the transmission of data packets without changing their wavelength and at least one other port for each optical arm, so that each of these ports is connected to a rejection filter (31) to receive the data packets at the different wavelengths and reintroduce the data packets reflected by this filter into the circulator; the converter (32) at output of each rejection filter enabling the conversion into a desired wavelength of the data packets not reflected by the filter. The invention can be applied to asynchronous packet or synchronous frame transmission packets.

Device for the frequency transposition of optical signals

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.

Optical crossconnect

A process for a simultaneous optical modulation transposition on several wavelengths. Use is made of a semiconductor laser able to freely oscillate on several longitudinal modes, the semiconductor laser being able to lock on a wavelength of an incident optical beam. The modulation is transposed on the modes which are not at the wavelength of the incident optical beam. Such a process may find particular application in optical telecommunication systems.

Process for simultaneous optical modulation transposition on several

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.

Optical device for the recovery of the timing of a coded signal

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.

Logic function generator using an optical transposition in a distributed

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.

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Camlez, France

Georges Claveau