Patent ID: 6441939
Filing Date: 2002-08-27
Classification: G02F,H01S

Abstract:
A system for regenerating a stream of solitons, the system including:an optical waveguide (G) between an input (2) for receiving a stream (S) of solitons to be regenerated and an output (4) at which a stream of regenerated solitons is supplied, the stream of solitons having an input wavelength and a clock rate defining successive clock times of the stream at a bit frequency B of the stream, a segment of the waveguide constituting an interferometer loop (6), the loop being closed by a loop coupler (8) coupling the waveguide to itself at two ends of the loop to constitute a Sagnac interferometer, a mid-point (10) of the loop being at equal distances along the waveguide from the two ends, and a loop amplifier (A) constituted by a semiconductor loop amplifier connected in series in said interferometer loop, the distance along the waveguide between the loop amplifier and the mid-point constituting an offset distance (L), said offset distance (L) being not less than a minimum value which is 20% of a nominal offset LN such that LN=c/2B â€ƒthe offset distance differing by at least this minimum value from illegal values equal to the product of the nominal offset multiplied by an even integer, c being the speed of light in said waveguide, a synchronization source (12) supplying an optical synchronization signal (Y) defining clock times (H1 . . . H4) for said stream S of solitons and having a synchronization wavelength and a power varying in accordance with an optical envelope of the signal, the envelope having a frequency equal to half said bit frequency, and means (14) for injecting said synchronization signal (Y) into said loop amplifier (A) to bring about therein cross modulation between said solitons and the synchronization signal, the amplitude and the phase of said envelope of the synchronization signal and an average value of the power of the signal being such that two solitons reaching said input (2) and occupying two immediately successive clock times (H3, H4) of said stream (S) of solitons are transmitted to said output (4) with their optical phase relationship inverted.