PHASE-MODULATED SIGNAL RECEIVING DEVICE

摘要

PROBLEM TO BE SOLVED: To adjust phase difference between a phase reference light signal and a receiving light signal without deteriorating receiving signal sensitivity.

SOLUTION: A monitor circuit 44 detects the average light receiving current of a photoelectric conversion device 41 for receiving a positive-phase intensity-modulated signal and outputs the detected current value to a control unit 38. The control unit 38 adjusts the heater current of phase adjustment heaters 35, 36 in such a way as to maximize or minimize the output of the monitor circuit 44 and controls the amount of delay of the phase reference light of a demodulator 31.

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