Semiconductor Laser High-precision Temperature Control System Basing on Digital Signal Processing

A high-precision self-adaptive proportion integral derivative (PID )control system for semiconductor laser is introduced. Output wavelength of the semiconductor laser can be drifted with the temperature changing. It affects the wavelength accuracy and the characteristics of semiconductor laser. In order to enable the semiconductor laser works steadily and maintain its temperature stability, this system is designed by using a digital signal processing (DSP) device - TMS320LF2407 as the central processor, using 24-bit A/D converter and 12-bit D/A converter as high-precision converters, adopting the parameter auto-tuning PID algorithm to accomplish the control of temperature. Basing on experimental results, using 24-bit A/D converter and 12-bit D/A converter and self-adaptive PID control method can improve the dynamic response and increase the steady precision for temperature of diode laser. Under the control of this system, the regulation time can be reduced to 80s, and the control accuracy of laser diode temperature can be achieved as 0.1°C