Semiconductor laser operating circuit

摘要

A semiconductor laser operating circuit comprises a signal limiting circuit which receives a beam intensity instructing signal, and limits values of the beam intensity instructing signal, which are larger than a predetermined value, to the predetermined value. A high-pass filter extracts high frequency components from the output of the signal limiting circuit. A monitor circuit detects the intensity of a laser beam produced by a semiconductor laser, and generates a signal representing the detected intensity. An adding and subtracting circuit adds the value of the output of the high-pass filter to the value of the beam intensity instructing signal, and calculates the difference between the value obtained from the addition and the value of the signal representing the detected intensity, which signal has been generated by the monitor circuit. The semiconductor laser is controlled by the output of the adding and subtracting circuit.