| 摘要 |
A semiconductor laser control apparatus comprises a light receiving part for receiving a laser beam emitted from a semiconductor laser, a comparator for comparing an output signal of the light receiving part and a reference signal having a level corresponding to a desired target value of the optical output, a clock generator for generating clock pulses, an up-down counter for counting the clock pulses and carrying out one of an up-count and a down-count responsive to a first control signal, a control part for controlling the clock generator and the up-down counter responsive to an error signal from the comparator, and a driving part for driving the semiconductor laser by supplying a current proportional to a counted value of the up-down counter. The control part outputs the first control signal which determines one of the up-count and the down-count depending on whether an output signal level of the light receiving part is lower or higher than the level of the reference signal and outputs a second control signal which is supplied to the clock generator and variably controls a frequency of the clock pulses depending on an absolute value of the error signal.
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