Optical cross-connect, method of switching over optical path, optical adm, and optical cross-connect network system

Abstract

An optical cross-connect has a plurality of input terminals to which photo signals are respectively inputted, a plurality of output terminals for respectively outputting the photo signals, and an optical switch for switching over an optical path between the input terminal and the output terminal. The optical switch, when switching over an optical path to a switchover target output terminal to which the optical path is newly connected from a pre-switchover output terminal through which the optical path is connected to the input terminal before the switchover, temporarily connects the optical path to both of the pre-switchover output terminal and the switchover target output terminal with a bridge connecting function. First and second monitor circuits for monitoring a state of the photo signal are disposed, respectively, between the input terminal and the optical switch, and between the optical switch and the output terminal. A connectivity of the optical switch is monitored from connectivity information, indicating the states of the photo signals before and after switching over the optical path, which is given from the monitor circuits. Prior to switchover of the optical path, the connectivity of the optical switch can be confirmed, and a reliability on the optical transmission system using the optical switch is thereby enhanced.