Patent ID: 6323991
Filing Date: 2001-11-27
Classification: H04B,H04J,H04L

Abstract:
A circuit for receiving an aggregate flow of optical signals including a first optical signal (P.sub.in) obtained by optical time division multiplexing of a plurality of tributary flows of optical signals, each having a bit rate equal to a given frequency (f.sub.1), and wherein a signal (e.sub.2) is produced by frequency division which is synchronous with said tributary flows and forms a synchronism signal for demultiplexing the aggregate flow, said circuit comprising:nonlinear electro-optical mixer means receiving as an input said first optical signal (P.sub.in) at a frequency (f.sub.0) to be divided in addition to an electrical signal (e.sub.3) at said given frequency (f.sub.1) and to generate as an output a second optical signal (P.sub.out) whose modulation spectrum includes, due to mixing action, a frequency corresponding to the difference between said frequency (f.sub.0) to be divided and at least one harmonic of said given frequency (f.sub.1) generated by nonlinear behavior of said mixer means;a feedback path connected to said mixer means and comprising opto-electronic converter means for converting said second optical signal (P.sub.out) into an electrical conversion signal (e.sub.1) returned to said electro-optical mixer means;filtering means along said feedback path for extracting from said spectrum the component at said difference frequency; andextracting means along said feedback path for deriving from said feedback path a signal (e.sub.2) at said difference frequency and resulting from frequency division.