DRIVING CIRCUIT FOR OPTICAL DEVICE

摘要

PROBLEM TO BE SOLVED: To lower the voltage of a driving circuit for an optical device, such as the semiconductor laser, optical switch, etc., and to reduce the power consumption of the circuit. SOLUTION: A driving circuit for optical device is provided with transistors Q1-Qn which are respectively connected in series with a plurality of optical devices P1-Pn, a resistor RE, switch circuits S1-Sn for turning on the transistors Q1Qn by using control signals, and an operation amplifier OPA which forms a constant-current circuit by inputting the voltage across both ends of the resistor RE to its (-) terminal and a reference voltage Vr to its (+) terminal and applying its output voltage across the bases of the transistors through the switch circuits S1-Sn between power terminals. Since the transistors Q1-Qn which are respectively connected in series with the optical devices P1-Pn are constituted in one stage, the voltage of the driving circuit can be lowered and the power consumption of the circuit can be reduced.