| 摘要 |
PURPOSE:To make the level of an optical signal, which arrives at an optical receiver, constant, by permitting data stations, which use a looped trunk line optical fiber as a common transmission line, to communicate with one another through an optical repeating device. CONSTITUTION:Optical signals with wavelength lambda1 transmitted from data stations 13-17 are coupled with a trunk line optical fiber 1 by T-shaped optical couplers 12a-12e, and transmitted in both the ways of the optical fiber. The optical signals propagating through the fiber 1 are received by an optical repeating device 18 theough the T-shaped optical couplers 12a-12e. The received optical signals are repeated and amplified by the device 18 to be converted into light signals with wavelength lambda2, which are sent out. Those optical signals are distributed to the stations 13-17 through the coupler 11, fiber 1, and couplers 12a- 12e respectively. If the breaking of the fiber 1 occurs, a trunk line controller 9 detects that and operates its optical switch from an open-circuit state to a closed-circuit state, so that both ends of the fiber are connected by the optical transmission line of the optical switch. |
