OPTICAL RECEIVER TERMINAL STATION, OPTICAL COMMUNICATION SYSTEM, AND OPTICAL SIGNAL CUTOFF DETECTING METHOD

摘要

An optical receiver apparatus capable of instantaneously performing an optical signal cutoff detection of an optical channel during switching from a currently used optical communication system to a standby optical communication system. An optical receiver terminal station apparatus or an optical receiver terminal station for receiving a light from an optical transmitter terminal station via a currently used line and a standby line comprises an optical signal cutoff detecting circuit that stores a received optical power, based on information indicative of the optical transmitter terminal station being outputting an optical signal and that performs a cutoff detection of the optical signal, based on a result of comparing the stored value with a received light.