OPTICAL BRANCHING UNIT FOR OPTICAL ADD DROP MULTIPLEXING

An optical add/drop multiplexer branching unit is provided, where the optical add/drop multiplexer branching unit includes: a trunk input end, a branch input end, a trunk output end, a branch output end, an optical add/drop multiplexer, a first coupler, a first detection circuit, and a control circuit, where the optical add/drop multiplexer includes an optical switch. A detection circuit detects whether a fault occurs in a trunk, and in a case in which a fault occurs in the trunk, a working mode is switched from a first working mode to a second working mode, to implement automatic redundancy on the trunk and ensure normal communication on a branch. According to the foregoing solution, a redundancy function is implemented without integrating an amplifier. Manual intervention is unnecessary, and a redundancy response speed is fast, thereby improving a redundancy effect, and significantly reducing an economic loss caused by system service transmission interruption. A used optical switch component is small in size, has a low requirement on structure space, and is of low complexity in structural design. Therefore, structural complexity is reduced, so as to reduce costs and improve reliability.