| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical signal receiving device capable of monitoring the reception state of an optical signal and selecting an appropriate circuit on the basis of the result of monitoring.SOLUTION: An optical signal receiving device comprises: photoelectric conversion means 31; a first circuit 32; a second circuit 33; signal switching means 34; timing reproducing means 35; signal detecting means 36; and control means 37. The photoelectric conversion means 31 converts an optical signal to an electric signal. The signal switching means 34 inputs the electric signal to the first circuit 32 or the second circuit 33. The timing reproducing means 35 is provided in the second circuit 33, and reproduces and outputs the timing of the input electric signal. The signal detecting means 36 detects power of the electric signal upstream of the signal switching means. When it is determined that the power of the electric signal detected is smaller than a prescribed reference value while a signal is input to the first circuit 32, the control means 37 controls the signal switching means 34 so as to input the electric signal to the second circuit 33. |
