Design of DFB Laser Drive and Temperature Control Circuit in TDLAS Gas Concentration Detection

Abstract In order to satisfy the requirements of TDLAS gas measurement, the DFB laser drive and temperature control system is designed with taking STM32F103RCT6 as the main control chip, including sine wave and sawtooth signal generation circuit, temperature acquisition circuit and temperature control circuit, etc. The sine wave and the sawtooth wave signal are respectively generated by using the DDS chip and the STM32 on-chip DAC, and the two are superimposed to control the constant current source to drive the laser. At the same time, the internal temperature of the laser is collected and controlled. The DFB laser with a center wavelength of 1653.7 nm is used to verify the CH4. The experiment proves that the system can generate stable laser driving signals and achieve precise temperature control. The temperature control accuracy can reach ±0.013 °C. The design satisfies the requirements of TDLAS gas detection system for laser driving and temperature control.