Research on Temprature Controling Technology of Laser Diode with Thermoelectric Cooler
|School||Harbin Institute of Technology|
|Course||Instrument Science and Technology|
|Keywords||temperature controlling technology of LD with thermoelectric cooler self - tuning Fuzzy - PID algorithm platinum resistance sensor TEC|
Laser diode is a new type of laser light sources. It has many characteristics such as small size, simple structure, low energy consumption, long service life and easy modulation. It has been widely used in the field of national defense military, communications, medical, industrial measures and so on. However, in the course of their work time accompanied by heat generation, temperature of laser diode increase will cause changes of output wavelength, the threshold current and output power, and other parameters, seriously affecting their work performance and service life. On this issue, this paper designs a DSP-based high-precision temperature control system to ensure the performance of the semiconductor laser stability. This paper’s main work has been accomplished as follows:A DSP-based high-precision temperature acquisition and control system is designed. The system is divided into temperature measurement unit, microprocessor unit and temperature control unit. Temperature unit with the A-level precision Pt1000 platinum resistance temperature sensor, adopts a three-lane bridge circuit, two high-precision operational amplifier, precision resistance to achieve a high precision and high-resolution temperature detection. Micro-processing unit chooses high-speed processor DSP as the core, with 16 high-precision A / D and D / A converter device to achieve high-precision temperature signal acquisition and high-precision acquisition signal output. Temperature control unit is made up of the thermoelectric cooler and professional control MAX1968 chip. With control of the microprocessor control voltage signal, it can realize two-way high-efficient temperature control to the semiconductor laser according to the ambient temperature.By analyzing the features of the semiconductor laser diode temperature control system, a control model based on fuzzy adaptive algorithm is designed. Due to the fuzzy control tache on the basis of general PID control system, the PID parameters can be amended according to the fuzzy-control rules. As a result, the system has not only the flexible and adaptable merits of the fuzzy control, but also the accuracy of PID control. To give the laser work environment a seal insulation treatment, a small temperature trap is designed. Make experimental verification and data analysis for the issue, glowing of semiconductor laser.The experiment demonstrates that the DSP-based high-precision temperature acquisition and control system and fuzzy adaptive control algorithm can achieve good results on the laser diode temperature control with an accuracy of±0.1℃, effectively control the infection to the laser diode performance parameters due to the temperature drift. So it has the value on actual appliance.