| 摘要 |
PURPOSE:To suppress a waveform change in an output voltage of a post-stage circuit even at a high level optical power signal reception by bypassing a current flowing to the circuit connected to the post-stage of an optical reception circuit when it reaches a setting current. CONSTITUTION:A voltage of a load resistor connected in series with a photodetector 3 outputting a current in response to the intensity of the received light is detected and compared (21) with a setting voltage. A voltage detection circuit 21 uses an output current of the photodetector 3 to detect a voltage caused across a load resistor 1, and an output current of the photodetector 3 is increased at the reception of a high level optical signal and a voltage caused across the load resistor 1 is also increased. When a voltage detected by the voltage detection circuit 21 in this case reaches a setting voltage or over, a part of the output current of the photodetector 3 is bypassed by a bypass circuit 17. Thus, a prescribed value or over of the current does not flow to a current/ voltage conversion circuit connected to the optical reception circuit and the deterioration of an output voltage waveform is suppressed. |
