| 摘要 |
PURPOSE:To reduce the loss of >=6dB of a directional coupler and to eliminate the operation unstableness of a light emitting device by using an electric switch to connect an input optical fiber, a sensor optical fiber, etc. CONSTITUTION:The light emitting device 1 and a port 2A provided to an optical switch 2 are coupled together by the input optical fiber 10 and ports 2B, 2C, and 2D, an optical sensor 3, a photodetecting device 4 for monitoring, and a photodetecting device 5 for the optical sensor are coupled by optical fibers 11, 12, and 13. Then, the switch switches connections among plural waveguides. Namely, while the ports 2A and 2B (2B and 2D) are connected in a state 1 (2), the ports 2C and 2D (2A and 2C) are connected with each other. The sensor 3 is a temperature measuring optical sensor and light incident from the fiber 11 is reflected by a total reflecting film and incident thereon again. Light beams from the fibers 12 and 13 are converted by photodetecting devices 4 and 5 into electrical signals, which are compared by an arithmetic processor 6, so that a signal indicating the detected quantity of the sensor 3 is outputted 16.
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