GAIN STABILIZING OPTICAL AMPLIFIER

摘要

PURPOSE:To compose all circuits by electric system by a method wherein the peak frequency of the gain distribution of an optical amplifier is controlled by the induced electric signal generated by an interacrion between input signal and carrier in the potical amplifier. CONSTITUTION:DC bias current from a DC source 3 and low frequency sine- wave signal omegam from an oscillator 5 are superposed and supplied to a semiconductor laser optical amplifier 2. Then inducted electric signal generated in the semiconductor laser optical amplifier 2 by an interaction between FM input signal light 1 and the low frequency sine-wave signal omegam is applied to a band- pass filter 11 and a 2omegam component is taken out. Then a processing circuit 12 judges wether the input signal carrier frequency is on the low frequency side or the high frequency side of the gain distribution taking the signal of the oscillator 5 as a standard. A DC source is controlled by this judgement and the maximum value of the gain of the semiconductor laser optical amplifier 2 is tuned to the carrier frequency of the FM input signal light 1.