| 摘要 |
PURPOSE:To make the peak-to-peak value of an optical output constant against the variance of the ambient temperature, by monitoring the output of a laser diode to control the DC bias of the laser diode and changing the crest value of applied pulses. CONSTITUTION:A current IS where a pulse current IP of a current switching circuit 2 which is interrupted in accordance with the digital signal inputted from an input terminal 1 is superposed onto a bias current IB of a DC bias current generating circuit 4 is applied to a laser diode 3 to emit light. A part of the optical output of the laser diode 3 is converted to a current IF in a photodiode 5, and a voltage VF generated in a resistance 7 by this current is compared with a reference voltage Vr in a comparator 6 to change the output of a DC bias current generating circuit 4. When the bias current IB is changed, a voltage VB between both ends of a resistance 8 is changed, and therefore, a comparator 9 changes the pulse current of the current switching circuit 2. |
