Frequency stabilization technologies of semiconductor laser

Semiconductor laser with narrow linewidth and high frequency stability has been widely used in precision interference measurements, optical frequency standards, laser communication, optical gyroscope, laser radar, measurements of fundamental physics constants and cold atomic system, et. The frequency drift of a free running semiconductor laser may be up to several GHz per day. Therefore, the research on frequency stabilization of semiconductor laser is extremely necessary. A variety of frequency stabilization techniques was developed. As an example of 780 nm semiconductor laser, the principles and experimental realizations of frequency stabilization were introduced, such as Doppler-free saturated absorption spectroscopy, Doppler-free Dichroic spectroscopy, modulation transfer spectroscopy, frequency modulation spectroscopy and frequency-to-voltage conversion technology, et al. Meanwhile, the performance and characteristics of different frequency stabilization methods were analyzed.