WAVELENGTH MULTIPLEXING APPARATUS AND SIGNAL CONVERTING APPARATUS

PROBLEM TO BE SOLVED: To provide a wavelength multiplexing apparatus and a signal converting apparatus, capable of being flexibly and inexpensively adapted to requirements for arrangement of equipment in a station house, station installation conditions and maintenance/operation, and capable of keeping the transmission quality high. SOLUTION: The apparatus comprises a multiplexing means for performing both/either multiplexing and/or demultiplexing between an optical signal, being transmitted independently or received by a plurality of signal converting apparatuses and having different frequencies and a wavelength multiplex signal transmitted through an optical multiplex transmitting path, a reference signal receiving means for receiving a reference optical signal outputted by the specified signal converting apparatus out of the plurality of the signal converting apparatuses and modulated by a reference signal to be a reference of synchronization in all or some of the signal converting apparatuses, and a reference signal distributing means for distributing the reference optical signal received by the reference signal receiving means to all or some of the plurality of the signal converting apparatuses.