To provide a semiconductor light emitting element drive circuit capable of an ideal optical output waveform having little jitter.
The semiconductor light emitting element drive circuit comprises a semiconductor light emitting element, a semiconductor light receiving element, a bias current setting transistor, and a crosspoint control circuit. The semiconductor light emitting element generates an optical output by supplying a modulated current and a bias current. The semiconductor light receiving element outputs an optical current by receiving the optical output by the semiconductor light emitting element. The bias current setting transistor sets a bias current to be supplied to the semiconductor light emitting element based on a bias current setting signal to be supplied to a control terminal. The crosspoint control circuit supplies the bias current setting signal to the control terminal of the bias current setting transistor so that the crosspoint of the optical output waveform becomes a predetermined level based on an electric signal corresponding to the optical current output by the semiconductor light receiving element.
Tatsuya Shioda
Shiro Terasaki
Masatoshi Shibata
Junji Kashiwaoka