An optical add-drop function part of an optical add-drop multiplexer has
an output end of transmitted light signal in which an optical termination
mechanism formed by an optical detector for detecting open of an optical
fiber, an optical switch, and an optical terminator are mounted. Further,
a reflection level calculation circuit, a reflection warning
determination circuit, and an optical switch selection circuit are
mounted to perform laser safety in the optical add-drop function part as
well. The laser safety part in the optical add-drop function part is
operated earlier than the laser safety part in an optical amplification
function part.