Study On Temperature Control System Of Laser Diode

Laser diode is widely used in industrial processing, precision measurement, communication fields etc. Laser diode is a temperature sensitive device. While the temperature changing, the output wavelength and power of laser diode will change, and its work life will be shortened. In order to ensure a good working performance, we must hold the temperature of the laser diode. In this paper we designed an automatic temperature control system of laser diode with the semiconductor refrigerator.Now, semiconductor refrigerator is the actuator of temperature control system of laser diode. Semiconductor refrigerator is based on Peltier effect. When pass on DC, semiconductor refrigerator will be heating or cooling. It can control the temperature of semiconductor laser. In this paper on the basis of analyzing the semiconductor refrigerator characteristic, we have designed its math model in the average based on small-signal analysis.Then, it has gotten the transfer function of this semiconductor on analyzing math models of laser diode and temperature sensor. Analyzed the transfer function and performance requirements of the system to design the PID controller and fuzzy self-adaptive PID controller for optimize the system. We have obtained the accuracy of the system on fuzzy self-adaptive PID control can reach 0.01℃.We adopt genetic algorithm to optimize the system. It does not require any initial information. It can find the global optimal solution. We design a PID controller based on genetic algorithm. And through simulation compared, we can see PID controller based on genetic algorithm is better than fuzzy self-adaptive PID and PID control.Finally, we design the hardware of the temperature control system. Analyzed the system of data collection, the Micro Controller Unit interface, the power drive and display part.