Supervisory control light transmitting method for a wavelength division multiplexing transmission system and wavelength division multiplexing transmission apparatus

摘要

In a wavelength division multiplexing transmission system having an optical transmission path which transmits wavelength division multiplexed light that is main signal light, supervisory control light is transmitted through the optical transmission path in the direction opposite to the direction of the main signal light. As a result, it is possible to restrain attenuation of the supervisory control light due to a Raman scattering phenomenon, thereby increasing a relay distance.