| 摘要 |
PROBLEM TO BE SOLVED: To realize a low price by limiting the number of high-speed type circuits required for improving the responsibility to the control of a luminescence strength of a semiconductor laser. SOLUTION: A semiconductor laser device is provided with a semiconductor laser LD which emits the light by being driven by driving signals, a monitoring photo diode PD which detects the emission output of the semiconductor laser LD, a minimum level setting circuit 23 which outputs the minimum level voltage Vmin for setting the minimum emission output of the semiconductor laser, a D-A converting circuit 21 which outputs a modulating data voltage Vdata for controlling the emission output of the semiconductor laser LD based on data signals which are inputted after receiving the maximum level voltage Vmax from a maximum level setting circuit 22, an adding machine 24 which adds the Vmin to the Vdata and outputs a reference voltage Vref, a differential amplifier 25 which compares the Vref with a monitor voltage Vmon and amplifies them, a first V-I converting circuit 26 which outputs a driving current Id1 of the semiconductor laser LD based on the result of the comparison, a second V-I converting circuit 28 which is consisted as a high-speed type circuit for overlapping a second driving current Id2 obtained from the Vdata on the Id1.
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