OPTICAL ADD-DROP MULTIPLEXER (OADM) DEVICE

An OADM device is provided with a variable optical attenuator (73) for attenuating a light signal into which a received light signal is demultiplexed by an optical demultiplexing functional unit (71), a modulating circuit (75) for piggybacking an ID number of a corresponding transmitting port onto the light signal by using the variable optical attenuator (73), an optical reception detector (84) for detecting the light level of a light signal received via a receiving port, a demodulating circuit (85) for extracting the ID number from the light level detected by the optical reception detector, an ID number management unit (91) for determining whether the ID number extracted by the demodulating circuit matches an ID number set thereby, and a notifying unit (9) for notifying a connection failure occurring in an optical patch cable (14) when the ID number management unit (91) determines that there is a mismatch between the ID numbers.