OPTICAL RECEIVER, ACTIVE OPTICAL CABLE, AND CONTROL METHOD FOR OPTICAL RECEIVER

摘要

PROBLEM TO BE SOLVED: To provide an optical receiver capable of speedily canceling an offset of a differential signal even when an optical signal varies in power with time as a light emitting element that an optical transmitter comprises deteriorates with time.SOLUTION: An optical receiver comprises: a light receiving element (11) which converts an optical signal into a current signal; a transimpedance amplifier (12a) which converts the current signal into a voltage signal; a differential amplifier (12d) which converts the voltage signal into a differential signal by differentially amplifying a difference between the voltage signal and a threshold voltage; and a control part (13) which repeats offset canceling processing including threshold voltage varying processing for varying the threshold voltage so that an offset voltage of the differential signal becomes smaller. The control part (13) writes the threshold voltage to a nonvolatile memory (14) at the end of operation of the control part (13) or periodically during the operation of the control part (13), and also reads a value of the threshold voltage out of the nonvolatile memory (14) at the start of the operation of the control part (13) and utilizes the read value of the threshold voltage as an initial value of the offset canceling processing.SELECTED DRAWING: Figure 1