Patent ID: 7761013

Claim:
An optical receiver circuit with an avalanche photodiode (APD) for receiving an optical signal with power and outputting a photocurrent corresponding to the optical signal, comprising: a bias generator for supplying a bias voltage to said APD; a first current sensor having a first detectable range and configured to detect the photocurrent, said first current sensor outputting a first signal that increases as the photocurrent increases; a second current sensor having a second detectable range wider than the first detectable range and configured to detect the photocurrent, said second current sensor outputting a second signal that decreases as the photocurrent increases; and a controller for controlling the bias generator based on the photocurrent detected by the first or second current sensor, wherein the controller sets the bias voltage to be constant when the power of the optical signal that is calculated based on the first signal output from the first current sensor is less than a predetermined value, and the controller decreases the bias voltage based on the second signal output from the second current sensor when the power of the optical signal is equal to or larger than the predetermined value.