A high precision temperature control system for ultra-stable laser reference cavity in space gravitational wave detection

To achieve space-borne gravitational wave detection aimed at 0.1mHz~1Hz frequency band, ultra-stable laser with high frequency stability and power stability are particularly important. High stable laser stabilized on high-precision Fabry-Pérot cavities is currently the most mature laser frequency stabilization technology and can achieve sub-Hz level frequency fluctuations at 1s level. To achieve the frequency stability of 30 Hz/√Hz at 0.1mHz ~ 1 Hz frequency band, long-term temperature stability characteristics of the laser reference cavity aimed at 10mK fluctuation should be fulfilled. This paper mainly introduces our work on active temperature stabilization method based on fuzzy PID control to stabilize the temperature fluctuation of the laser reference cavity, reducing the impact of cavity length changes. By actively stabilizing the cavity's temperature, we explore the active cavity temperature noise suppression strategy to improve the locking performance of lasers.