| 摘要 |
PURPOSE:To simplify the optical repeater, to attain high reliability and to economize the system by providing an optical synthesizing/ branching device branching and reflecting a back scattering light to an incoming and an outgoing amplifier to an optical reflection circuit of each optical repeater. CONSTITUTION:A photoelectric transmission line terminal station 1 locates the position of a fault caused on an optical transmission line T among optical repeaters A1'-An'. An optical synthesizer and branching device 11a branching and reflecting a back scattering light 5a(2) to an output of an incoming side optical amplifier 4a(1) and an optical synthesis and branching device 11b to couple a back scattering light 5a(2) with an outgoing optical transmission line at an output of an outgoing optical amplifier 4b(1) are provided to e.g. an optical reflecting circuit C1 among optical reflecting circuits C1,.... In this case, back scattering lights 5a(1), 5b(1) caused in incoming and outgoing optical fibers 3a(2), 3b(1) are reflected respectively to terminal stations 1, 2 through the circuit C1. Thus, an optical receiver and a control circuit to activate an optical shutter are not required and one optical reflection circuit only is used for locating a faulty point in common for terminal stations 1, 2. |
