| 摘要 |
PROBLEM TO BE SOLVED: To attain cost down for duplex configuration by irreducibly minimizing the spares of optical receivers. SOLUTION: When any fault occurs at an optical transmitter 12-1 of an active system, a signal selector circuit 11 of a multiplex wavelength transmitting means 10 switches a signal S1 from the optical transmitter 12-1 to 13-1, and a multiplex wavelength multiplexing, means 13 sends the optical signals of optical transmitters 12-2 to 12-m and 13-1 to an optical transmission line 52-1 while multiplexing their wavelengths. At a multiplex wavelength receiving means 20, the signal is received by an optical receiver 22-1 or a reserve system optical receiver 23-1 with the wavelength from the spare system optical transmitter 13-1 and outputs it through a signal selector circuit 24. Besides, when any fault occurs at an active system optical transmission line 52-1, the wavelength multiplexing means 14 of the multiplex wavelength transmitting means 10 sends optical signals outputted from the optical transmitters 12-1 to 12-m to an optical transmission line 52-2 while multiplexing their wavelengths, and a wavelength demultiplexing means 21 of the multiplex wavelength receiving means 20 connects the wavelength multiplexed optical signal inputted to the optical transmission line 52-2 to optical receivers 22-1 to 22-m while demultiplexing the respective wavelengths. Thus, the spare optical transmitter/receiver systems are provided for (n) channels in the transmission of wavelength multiplexed for (m) channels, device and transmission line faults are dealt with. |
