WAVELENGTH MULTIPLEXED LIGHT AMPLIFYING REPEATER

摘要

PURPOSE:To evaluate the transmission quality of each multiplexed wavelength by selecting and outputting a signal of a prescribed wavelength out of branched wavelength multiplexed optical signals and then looping back the selected optical signal. CONSTITUTION:The wavelength multiplexed signals of wavelength lambda1-lambda4 are demultiplexed for each wavelength via an optical demultiplexing circuit 44 and a demultiplexer 11 and then inputted to an optical switch 12. A remote control signal receiving part 14 fetches the optical signals demultiplexed from an UP optical amplifier 42 and extracts a control signal of frequency f1 superposed on the wavelength lambda1 for example. Then the part 14 controls the switch 12 to transmit the optical signal of wavelength lambda1. The part 14 consists of an O/E 15 which converts the optical signal received from the amplifier 42 into an electric signal and a control signal processing part 16 which extracts a signal to control the switch 12. The optical signal of wavelength lambda2 is inputted to a multiplexer 46 set on a DOWN optical transmission line 43 via a multiplexer 13 and multiplexed by the DOWN optical signals of wavelength lambda1-lambda4. These multiplexed signals are looped back to a transmitting end office. In such a constitution, the transmission quality can be evaluated for each multiplexed wavelength.