OPTICAL COMMUNICATION NETWORK

摘要

PURPOSE:To enable the optical communication between arbitrary optical terminal stations by adjusting the signal which is transmitted by its own station and transmits one round of a loop state optical communication network so that the C/N of this received signal may be within a certain range at an optical terminal station. CONSTITUTION:A carrier wave modulation into the carrier wave signal of its own station performed for a signal to be transmitted in a loop from an input/output device 24 via a carrier wave modulation circuit 33. This carrier wave signal is transmitted in the loop from an optical transmitter 22 via an amplitude adjusting circuit 44 and a signal synthetic circuit 34. An optical receiver 23 receives the carrier wave signal from other optical terminal station and the carrier wave signal of the own station which made one round of the loop and returns. A C/N detection circuit 40 detects the carrier wave frequency and noise components of its own station from among the signals of the optical receiver 23 and a C/N detection value 45 is obtained. A comparator circuit 41 outputs a control signal 46 for increasing the amplitude of the output signal 48 of the circuit 44 when the detection value 45 is lower than a reference value 42 and outputs a control signal 47 for decreasing the amplitude of the signal 48 when the value is higher than a reference value 43.