Patent ID: 7697582

Claim:
A laser driving circuit comprising: a first wiring pattern and a second wiring pattern which are connected to a main wiring pattern; a first circuit which is connected to said first wiring pattern and has a semiconductor laser element and a laser driving device for driving the semiconductor laser element; a second circuit which is connected to said second wiring pattern and has a compensation element and a compensation driving device; and an impedance control unit, connected to said first wiring pattern and said second wiring pattern, for selectively increasing impedances to in-phase signal components in a signal flowing through said first wiring pattern and said first circuit and a signal flowing through said second wiring pattern and said second circuit, wherein the first circuit is a light-emitting circuit which causes the semiconductor laser element to emit light, said second circuit is a compensation circuit having the same electrical characteristics as an electrical characteristic of the light-emitting circuit, and the laser driving device and the compensation driving device are complementarily driven.