Nonlinear polarization drift modeling and real-time compensation in LCVR-based laser power stabilization systems

The stability of laser power is a crucial prerequisite for the reliable operation of spin-exchange relaxation-free (SERF) magnetometer systems. This paper investigates the temperature drift error in the liquid crystal variable retarder power stabilization systems, which influences the long-term laser power stability. An optical transmission model is established to analyze the influence of laser polarization error caused by temperature fluctuations. Based on this, a compensation model accounting for both absolute temperature <i>T</i> and its time derivative <i>d</i><i>T</i> is implemented on the field-programmable gate array and the digital signal processor platform. Experimental results demonstrate improved long-term power stability, improving the root mean square stability from 1.4×10^-3 to 5.6×10^-4 in a 24 h test, and the Allan deviation is 9.8×10^-6 at 100 s. Compared with previous methods, our system incorporates a real-time temperature drift compensation model based on both absolute temperature and its time derivative. The proposed approach effectively suppresses polarization-related power fluctuations in precision optical systems and improves long-term SERF gyroscope systems.