| 摘要 |
PROBLEM TO BE SOLVED: To generate a monitor signal without using a laser module for the monitor signal by transmitting wavelength other than the wavelength of a main signal in the gain band of an optical amplifier by a ring oscillator and modulating the wavelength monitor signal. SOLUTION: To a signal input terminal 110, a light signal generated by multiplexing the main signal of wavelength λsv and an upstream monitor control signal is inputted. This multiplex signal is demultiplexed by a WDM filter 101 into the main signal and monitor control signal. The main signal of wavelength λs is inputted from a WDM filter 101 to a 1st optical amplifier 107 through an optical coupler 106, amplified by a 1st optical amplifier 107, and outputted to a signal output terminal 111 through an optical demultiplexer 108. At the same time, part of the main signal is demultiplexed by the optical demultiplexer 108 and inputted to the 1st optical amplifier 107 again through a 1st optical band-pass filter 109 and an optical couple 106. |
