Optical signal resynchronization method and device

摘要

To resynchronize input optical signals with different optical carrier frequencies f1, f2 a delayed optical signal is created by applying a variable time-delay to one of the signals. A combination signal is formed by coupling measurement optical signals respectively obtained from the delayed signal and from the other input signal. A mixed signal is formed by injecting the combination signal into a non-linear optical device. A filtered signal is formed from the mixed signal using a filter tuned to an optical frequency f3 equal to p.f1+q.f2, p and q being relative integers such that the frequency f3 is different to the frequencies f1 and f2 of the carrier waves. The variable time-delay is controlled in accordance with a control electrical signal representative of the average value of the intensity of the filtered signal. Applications include wavelength-division multiplex optical communication systems.