WAVELENGTH DIVISION MULTIPLEX OPTICAL TRANSMITTER

A plurality of amplified spontaneous emission light signals are output by using a plurality of optical amplifiers 12a and 12b which has a signal input terminal terminated at no reflection, the amplified spontaneous emission light signals are band-filtered in a plurality of optical band pass filters 13a and 13b respectively to obtain a plurality of spectrum slice optical signals, and the spectrum slice optical signals functioning as a plurality of dummy optical signals are multiplexed with a plurality of modulated optical signals.