| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical line changeover system that can enhance the reliability of an optical communication network by providing a so-called protection function to the system to set a detour route to a standby optical transmission line to ensure a transmission line and decreasing number of optical switches that are components on the occurrence of a fault in the transmission line through which an optical signal is transmitted in the optical communication network. SOLUTION: The optical line changeover system 10 is provided in terminal stations in an optical communication network having active transmission lines 5, 6 and standby transmission lines 7, 8 consisting of a plurality of optical fibers installed in a plurality of terminal stations and between terminal stations processing the optical signals and selects other transmission line when any transmission line has a fault. The system 10 is provided with optical multiplexers/demultiplexers 11, 12 with an optical add drop function, a plurality of optical switches 13-18 that are placed at both upper and down streams of optical signals with the optical multiplexers/demultiplexers 11, 12 inbetween, photo diodes 19-22 that monitor the optical signals transmitted through the active and standby transmission lines, and a controller 24 that applies changeover control to a prescribed optical switch among a plurality of the optical switches on the basis of a monitor result of the photo diodes. |
