Abstract: Tunable semiconductor laser is one of the most important devices in tunable diode laser absorption spectroscopy (TDLAS) system. The stability of the laser output wavelength directly determines the accuracy and stability of system measurements, and the laser output wavelength is mainly controlled by the injection current and operating temperature. A laser drive control circuit is designed, and PID control is utilized to implement thermostatic control of the laser operating temperature. The circuit can not only provide high-precision and low noise injection current, but also have a complete safety protection function for the laser. Firstly, the short-term test and analysis of the injection current and temperature control are carried out. Then, the designed circuit is applied to a laser with a central wavelength of 1512 nm, the temperature and current tuning characteristics of the laser are experimentally test and analyzed, and the stability of the laser output wavelength is tested in both short-term and longterm. The standard deviation of the laser output wavelength is found to be 0.0002, which meets the requirements of TDLAS system for constant current and constant temperature control of laser, and indicates that the designed drive control circuit has realized the high-precision driving control of the semiconductor laser.

Key words: optoelectronics, tunable semiconductor laser, current drive, TEC temperature control