Patent ID: 6990130

Claim:
A semiconductor laser optical output control circuit for controlling an optical output of a semiconductor laser to a desired intensity in accordance with a supplied drive current, comprising: an optical output detecting means for detecting the optical output of said semiconductor laser; a first detecting means for detecting a first level of said optical output detected by said optical output detecting means; a second detecting means for detecting a second level of said optical output detected by said optical output detecting means; a first optical output setting means for giving a first setting value of a first level in the optical output of said semiconductor laser; a second optical output setting means for giving a second setting value of a second level in the optical output of said semiconductor laser; a first switching means for switching and first and second setting value signals of said optical output given by said first and second optical output setting means; a third detecting means for detecting the first setting value signal among outputs of said optical output setting switching means; a fourth detecting means for detecting the second setting value signal among the outputs of said optical output setting switching means; a first comparing means for comparing the detected output of said first detecting means with the detected output of said third detecting means and outputting the comparison result; a second comparing means for comparing the detected output of said second detecting means with the detected output of said fourth detecting means and outputting the comparison result; a second switching means for switching and outputting the comparison results of said first and second comparing means in synchronization with the switching by said first switching means; and a current supplying means for supplying said drive current in accordance with the output signal of said second switching means to said semiconductor laser.