PURPOSE: To improve reliability of the system using an optical switch, by detecting light leakage by a photoelectric transducer to discriminate the trouble of the optical switch when the switching operation is incomplete.
CONSTITUTION: Photoelectric transducers 10 and 11 are provided near ends of optical fibers 2 and 3 in the receiving side, and outputs of photoelectric transducers 10 and 11 are applied to detecting circuits 12 and 13, and alarm signals ALM1 and ALM2 are output for the input of a prescribed level or more. For example, when optical fiber 1 in the light source side is not switched and connected to optical fiber 2 in the receiving side surely as shown by the dotted line, the light signal from optical fiber 1 in the light source side is leaked and is incident onto photoelectric transducer 10. When it is detected by detecting circuit 12 that the output of this photoelectric transducer is an allowable level or more, alarm signal ALM1 is output. Consequently, it can be discriminated easily that the switching operation between optical fibers 1 and 2 is incomplete.
IWAMA MASAMICHI
MURASE TETSUO
| JPS5087338A | 1975-07-14 |