OPTICAL TRANSMITTER-RECEIVER

摘要

PROBLEM TO BE SOLVED: To make the reception level of an opposite party constant independently of a loss of a transmission line by controlling an LD drive current depending on a peak level of a reception signal so as to make an output of an LD variable. SOLUTION: A reference voltage generating circuit 17 of a transmission section 1 detects a peak voltage of a reception signal from an output of a preamplifier 22 of a reception section 2 and generates a voltage being a difference between the detected peak voltage and a received reference voltage corresponding to a reference optical reception level. An optical output control voltage generating circuit 18 generates a voltage controlling an optical output of a laser diode(LD) 12 with an output of the circuit 17 and outputs of an output level monitor voltage generating circuit 14 and an APC reference voltage generating circuit 15. An LD current control circuit 16 gives a voltage to control an output power of the LD 12 with an output of the circuit 18 to an LD drive circuit 11. Thus, a transmission level is set so that a reception of an opposite transmitter-receiver is made constant independently of a loss of a transmission line.