Patent attributes
To demultiplex a low-speed optical pulse signal from a high-speed optical pulse signal, an optical clock generator generates an optical clock of a control wavelength λp at a predetermined frequency out of a pulse signal light of a signal wavelength λs. On one side of a saturable absorber, an optical band reflection mirror is disposed to reflect a light of the signal wavelength λs and to transmit a light of the control wavelength λp. A pulse signal light of the signal wavelength λs reciprocates in the saturable absorber. An optical pulse of the pulse signal light of the signal wavelength λs enters the saturable absorber almost simultaneously with different optical pulses of the optical clock on the ways of going and returning. The saturable absorber has a transmission factor relative to the signal wavelength λs. The transmission factor varies as the saturable absorber absorbs a light of the control wavelength λp.