| 摘要 |
PURPOSE:To make it possible to adjust optical output simply, by providing a second amplifier circuit, which guides out the optical output voltage of a laser element that determines the light output from a semiconductor laser element, and providing a second variable resistor, which varies the amplitude of the second amplifier circuit and adjusts the optical output of the semiconductor laser element. CONSTITUTION:A laser diode LD outputs laser light. A photodiode PD receives the laser light and flows a monitored current I1 to a resistor R1. Therefore, at a connecting point of the anode of the photodiode PD and the resistor R1, a first output voltage V1, which is determined by the resistance value of the resistor R1 and the monitored current I1, is generated. The first output voltage V1 is imparted to a non-inverted input terminal of a first operation amplifier 1, which is a first amplifier circuit. To an inverted input terminal of the first operation amplifier 1, a first reference voltage E, which is set by a first variable resistor VR1 and a resistor R2, is imparted. Thus, the adjustment of dispersion in characteristics of the semiconductor laser element and the adjustment of the optical output of the semiconductor laser element can be carried out in an alloted manner. Therefore the adjustment work is simplified. |
