| 摘要 |
PURPOSE: To simplify the switching processing between the active and stand-by systems by monitoring the input optical signals at the optical cut-off detection part of an optical amplifier circuit prepared at an active optical transmission part and switching an active system to the stand-by system in an input cut-off state by stopping the operation of the optical amplifier circuit. CONSTITUTION: The optical signals are transmitted from an electricity/light conversion means (OS, 5 of an active optical transmission part 1 via an optical amplifier circuit 3 and an optical connector 8. At the same time, the optical signals sent to an amplification part 3a of the circuit 3 from the OS2 are monitored by an optical cut-off detector 3b. When an optical cut-off state is detected, the operation of the part 3a is stopped by the detection output of the detector 3b. Then the part 1 is switched to a stand-by optical transmission part 4 by a switch means 7. Then the optical signal retrogressing on an optical cable is detected at an optical reflected light detection part 6c as long as an optical connector 9 of the part 4 is opened. Thus the operation of the OS 5 is stopped, so that the large output light emitted from the open connector 9 is prevented. As a result, the satisfactory switching processing is simplified between both parts 1 and 4. |
