France Telecom

France Telecom Etablissement Autonome De Droit Public

Patrice Pottier

Rene Auffret

Georges Claveau

Mouhammad Jamil Chawki

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.

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Lannion, France

Patrice Pottier