| 摘要 |
PURPOSE:To stabilize the output of a semiconductor laser while using a small capacity thermo-electric cooling element by compensating the dynamic range of a temperature to be controlled by altering the set operation temperature of the laser and controlling the driving current of the laser having small control time constant. CONSTITUTION:The operating temperature of a semiconductor laser 1 is detected as a voltage V by a temperature sensitive element 6 in an operation temperature controlling system B, and is compared with the voltage range predetermined in window comparators 81, 82. The voltage ranges of more than the detecting voltage value V0 at the reference operation temperature t0 and lower than the V0 are respectively set in the comparators 81, 82. Thus, the reference voltage E1 or E2 is selected by the comparator 81 and a gate circuit 91 and the comparator 82 and a gate circuit 92, and is applied to a comparator 10, a thermo-electric cooling element 12 is operated by the compared output, and the laser 1 is retained at the temperature t1 or t2 corresponding to the voltage E1 or E2. Simultaneously, the driving current is controlled by a photodetector 3 and the comparator 4 of a control system A. |
