小功率半导体激光器的驱动方法设计

Design of driving method for low power semiconductor laser

在光散射测量系统中,半导体激光器(LD)的工作稳定性直接影响检验结果。为了得到稳定的光功率输出,设计了包含自动温度控制与自动电流控制的LD驱动系统。应用0.5 mA恒流源对PT100温度传感器供电,将LD工作温度转化为电压信号,经前置放大电路与电压比较电路处理后,通过PI控制半导体制冷实现恒温控制系统;根据闭环负反馈原理设计自动电流控制系统以及相应的辅助电路,能为LD提供稳定的、连续可调的驱动电流。经实验表明,系统在驱动额定功率为20 mW下工作时,可保证激光器输出功率稳定性优于0.2%。

In the light scattering measurement system, the stability of the semiconductor laser diode （LD） directly affects the test results. In order to obtain stable output optical power, a system to drive LD was designed, which included automatic temperature control system and automatic current control system. PT100 temperature sensor, whose power supply was 0.5 mA constant current source, after the preamplifier circuit and voltage circuit was treated, through the PI system controlling the semiconductor refrigeration and realize constant temperature control system. According to the closed-loop negative feedback principle, the automatic current control system and the corresponding auxiliary circuit were designed, which could provide stable, continuous adjustable driving current for LD. The experimental results show that in driving rated power of 20 mW laser, system can ensure the stability of laser output power better than 0.2%.