| 摘要 |
PURPOSE:To provide an optical digital modulation circuit in which a duty of an optical output is unchanged even when an ambient temperature is subject to change and large scale circuit integration is facilitated with respect to the optical digital modulation circuit. CONSTITUTION:This circuit is provided with a clamp section 1 fixing an L level or an H level of an input digital signal to a prescribed voltage, an amplitude adjustment section 2 outputting a pulse with a large level when an input voltage is small and outputting a pulse with a small level when the input voltage is large with respect to a nearly center voltage level of the pulse of an input digital signal fixed to a prescribed voltage by the clamp section 1, a laser diode drive section 3 driving a laser diode with a pulse inputted through the clamp section 1 and the amplitude adjustment section 2, an optical output monitor section 4 monitoring an optical output of the laser diode from the laser diode drive section and outputting a voltage corresponding to the monitored light, and a differential voltage output section 5 outputting a difference voltage between the output voltage from the monitor section 4 and a reference voltage as an input voltage to the amplitude adjustment section 2. |
