| 摘要 |
PURPOSE:To keep always the operating temperature of a semiconductor laser at a set temperature by controlling a thermoelectric effect element in response properly to change in the heat value of the semiconductor laser and a change in the environmental temperature on the periphery of the semiconductor laser. CONSTITUTION:As the heat value Q of a semiconductor laser 4 is in proportion to an injection current ILD, a fixed resistor RF is provided in the midst of the series circuit including a current feed source 9 which feeds the injection current ILD to the semiconductor laser 4 and the semiconductor laser 4 and it is utilized for the potential drop V to be proportioned to the injection current. A thermistor 13 functions as an operating temperature detecting part to detect the operating temperature Tt of the semiconductor laser 4 and a thermistor 14 functions as an environmental temperature detecting part to detect the environmental temperature Tn of the laser. Detected outputs ET1 and ET2 detected by these thermistors 13 and 14 are each inputted in an operational amplifier 17 through temperature and voltage conversion circuits 15 and 16. This operational amplifier 17 has a function to generate a voltage V proportioned to a temperature difference DELTAT. |
