| 摘要 |
PURPOSE:To switch the optical fibers only at the receiving end side by controlling the connection between the 1st nd 2nd optical switches in response to the switch control information received from a receiving part. CONSTITUTION:The optical transmitter-receiver reception parts 16 and 22 are connected with switching to the other end of each of working optical fibers 11 and 17 as well as to optical switches 25 and 24 via optical switches 13 and 19 respectively. While both ends of a spare optical fiber 23 are connected with switching to an optical branching device 26 and the switch 19 as well as to an optical branching device 27 and the switch 13 via switches 24 and 25 respec tively. These pairs switches 13/19 and 24/25 are constituted so that both fibers 11 and 17 are set at the connection positions s shown by solid lines in a normal mode. While both ends of the fiber 23 are connected to the devices 26 and 27 via switches 24 and 25 respectively. If the fiber 11, for example, has a fault, the switches 13 and 25 provided at the receiving end side of the fiber 11 are switched to the positions shown by the broken lines respectively. Thus the fiber 11 is switched to the fiber 23. |
