| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical receiver of a simple configuration, low noise and low distortion by switching and selecting an amplifier based on the light receiving state of an optical converter element. SOLUTION: A low noise amplifier 21 is connected to the anode terminal of an optical converter element 1 for receiving an optical signal, and a low distortion amplifier 22 is connected to the cathode terminal. The output signals of the low noise amplifier 21 and low distortion amplifier 22 are outputted through a synthesizer 11 to the main amplifier 14. A discrimination circuit 3 connected to the cathode terminal of the optical converting element 1 compares the output electric signal of the optical converting element 1 with the reference value set in advance. When it is discriminated by the discrimination circuit 3 that the input level of the optical signal is lower that the reference value, a control circuit 4 drives switch elements 11 and 12 to stop the flow of signals into the low distortion amplifier 22 . When it is discriminated by the discrimination circuit 3 the input level of the optical signal is higher than the reference signal, switching is performed so as to input the electric signal to the low distortion amplifier 22 . |
