Research Of LD Fully Digital Temperature Control System Based On DSP

The temperature of laser diode has a very important effect on its performance. The output power and center wavelength will drift following the temperature, and the lifetime of LD is also affected by the temperature. In order to maintain good performance, the temperature of LD must be well controlled.A fully digital temperature control system for high power laser diode array is designed in this paper, which achieves the characteristics of simple harware circuit, high integration, fast response speed, high precision and wide range of temperature control.The thermoelectric cooler (TEC) and digital signal processor (DSP) with high data processing ability are used in the real-time temperature control system. The digital temperature sensor DS18B20 is applied to measure the temperature, and the digital-controlled potentiometer (DCP) X9111 used to adjust the output voltage of the power supply module can change the flow of refrigeration of TEC for temperature control. In order to improve the veracity and stability of the temperature control system, the digital PID controller is designed. The PID parameters of the control system are adjusted by the experiment under the MATLAB simulation environment, and the PID control arithmetic programme is accomplished during the software of control system. Meanwhile, the interface programme is completed to assure the communication between the DSP and external digital device. The temperature contol system can afford power of refrigeration up to 50W, which is applicable to the high power LD.The digital temperature control system has been used in experiment research of temperature control, of which closed loop and open loop characteristics have reached the anticipant effect. The research of LD fully digital temperature control system becomes the engineering application basis of all-solid laser temperature control, and which can be applied in many areas.