| 摘要 |
PROBLEM TO BE SOLVED: To obtain a light transmitter without affecting other communication channels, when the wavelength and level of signal light to be outputted are changed by stopping a first light source and outputting an output light from a second light source, when abnormality is detected. SOLUTION: Optical signals of intrinsic wavelength are transmitted by each of (n) light transmitters 1. The optical signal from a transmitting circuit 2 is outputted to an output port of an optical coupler 4. The transmitting circuit 2 is provided with a circuit to detect the abnormality of a transmitted signal, and an abnormality signal is outputted for a monitoring circuit 5, when the abnormality in at least one of a laser diode and its output light is detected. The abnormality to be detected by the abnormality detection circuit is, for example, the wavelength of the transmitted light and change of output of the transmitted light. The output of the optical signal of the transmitting circuit 2 is stopped, when the abnormality signal is received by the monitoring circuit 5. Continuous light with the same wavelength and at the same level as the optical signal to be outputted by the transmitting circuit 2 is simultaneously outputted from a dummy light-transmitting circuit 6 by the monitoring circuit 5. |
