Optical mixer.

摘要

An optical mixer is provided for up/down-converting a first intensity-modulated optical signal (S1), the mixer comprising an optical amplifier (20) and gain-modulating means (23) for modulating the gain of the optical amplifier. The gain-modulating means (23) comprises means for generating a second intensity-modulated optical signal (S2) and launching it into the optical amplifier (20) at an intensity to cause the amplifier to operate at least partially within its saturated gain region whereby to cause the gain of said amplifier to be modulated at the frequency of modulation of said second optical signal (S2).