Patent ID: 7209666

Claim:
A system for recovering a clock signal from an optical signal which is received as an amplitude modulation of an optical carrier wave, wherein said amplitude modulation is synchronized with a clock rhythm, said system comprising: a first optical clock recovery device which receives said optical signal and supplies a first optical clock signal in response to said optical signal which is received; and a second optical clock recovery device which receives said first optical clock signal from said first optical clock recovery device and supplies a second optical clock signal in response to said first optical clock signal which is received, wherein optical power of said first optical clock signal, which is supplied by said first clock recovery device, is less than optical power of said optical signal which is received, wherein said first clock recovery device and said second clock recovery device comprise a first self-pulsating laser and a second self-pulsating laser, respectively, which respectively supply said first clock signal and said second clock signal, wherein carrier wavelengths of said first clock signal and said second clock signal are different.