| 摘要 |
PURPOSE:To enable the change of attenuation quantities separately with each of signals of different wavelengths by separating light signals by each wavelength in light transmission paths where wavelengths are multiplexed. CONSTITUTION:The light signal (down signal) of the wavelength lambdaLL which is inputted from one light transmission path 1 and is outputted to the other light transmission path 2 and the light signal (up signal) of the wavelength lambda21 which is inputted from the light transmission path 2 and is outputted to the light transmission path 1 are assumed. The down signal demultiplexed by a 1st multiplexer/demultiplexer 11 is attenuated by a 1st variable optical attenuator 12 and is multiplexed by the 2nd multiplexer/demultiplexer 14 in this case. On the other hand, the up signal is demultiplexed by the 2nd multiplexer/demultiplexer 14 and is further attenuated by the 2nd variable optical attenuator 13, following which the signal is multiplexed by the 1st multiplexer/demultiplexer 11. The attenuation quantities respectively different with the wavelengths are thereby set to the up signal and the down signal. |
