| 摘要 |
PURPOSE:To readily design a circuit and to set the regulating by inputting a sampling voltage after correcting the irregularity of the output characteristics of a semiconductor laser to an output regulating circuit and a protecting circuit, and controlling the driving circuit of the laser by the outputs of the both circuits. CONSTITUTION:The photo detector of a semiconductor laser 1 is composed of a diode 2 and a resistor 7, and an amplifier 8, a variable resistor 9 and a resistor 10 form means for correcting the irregularity in the output characteristic of individual semiconductor lasers. A sampling voltage V1 input to the terminal (b) of a gate circuit 12 is sample-held in a capacitor 13 by a sampling signal input to a terminal (c). An amplifier 14 compares the voltage V1 with a reference voltage, and controls the output of the laser 1 constantly. When the output of the laser 1 abruptly increases so that the voltage V1 increased larger than the reference voltage V2 in the amplifier 20 of a protecting circuit 23, a switch 22 is closed by the output of the amplifier 20, the transistor 4 is turned OFF, and the output of the laser 1 is suppressed to the maximum allowable output or lower. |
