| 摘要 |
PURPOSE:To obtain a semiconductor laser-excited laser having a stable optical output by lowering a temperature of a heat sink by a temperature corresponding to a product of power consumption change of a light irradiating point due to a variation in a driving current of the semiconductor laser owing to a negative feedback of an optical output of the laser and a thermal resistance between the heat sinks. CONSTITUTION:Part of a laser output light is guided to a photodetector 29, and further fed back to a semiconductor laser. Then, a temperature change DELTATH = a junction voltage VLXa driving current change DELTAILX thermal resistance RTH of a heat sink is calculated by a calculator 37. Further, the DELTATH is subtracted from a temperature set value 38 of the heat sink by a differential amplifier 39, and a set value 42 of new temperature is obtained. The heat sink temperature of the semiconductor laser is obtained from the output of a temperature sensor 22 through an amplifier 40. A difference between the output value 43 of the amplifier 40 and the set value 42 is obtained by a differential amplifier 41, and its output is fed back to the heat sink temperature of the semiconductor laser by a thermoelectric cooling element. |
