PURPOSE: To improve duty accuracy, and to easily control the extraction of a clock waveform, by providing a photodetector, an AC amplifier, and a Schmitt trigger circuit, providing a pre-amplifier and a main amplifier as the AC amplifier, and constituting the latter with a CMOS.

CONSTITUTION: A receiver 3 consists of the photodetector PD, the AC amplifier, and the Schmitt trigger circuit ST, and the AC amplifier is provided with the pre-amplifier consisting of a video amplifier VA, and the main amplifier M, and the main amplifier M is constituted of a MOS amplifier having MOS constitution resistant to saturation depth. By constituting the device as stated above, it is possible to prevent the duty accuracy from being affected by the fluctuation of a level even when it is generated, and also, to prevent the skew of a reproduced waveform from being generated, and to obtain a characteristic and performance suitable for an optical fiber data link such as especially digital audio, etc.