| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical transmission system in which safety is ensured by preventing radiation of dangerous high output light, when a connector is connected/disconnected or an optical fiber is broken. <P>SOLUTION: Multiplexed wave signal light B is amplified by an optical amplifier 31 and transmitted through an optical fiber 32. The multiplexed wave signal light B is transmitted is branched by a branch coupler 33 into pumping light c and branch light d. The branch light d is inputted to a signal light passing filter 34 and only a monitoring frequency component h is extracted. The monitoring frequency component h is converted, by a signal light monitor 35, into a monitoring electric signal j. The monitoring electrical signal j is sent to a tone detector 40, and detection signal k is outputted therefrom. Since the multiplexed wave signal light B is not propagated when the optical fiber 32 is broken, for example, the detected signal k will not be generated from the tone detector 40, but a control signal m is outputted from a control section 38 and a pumping light source 37 is stopped instantantly. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
