Thermal locking-based optical parametric oscillation: noise suppression in a WGM cavity

We propose a frequency stabilization system based on thermal locking, utilizing the thermo-optic effect in a whispering gallery mode (WGM) resonator. By coupling the WGM resonator with an ultra-stable laser, low-frequency noise can be stably suppressed. Additionally, through intracavity optical parametric oscillation, this noise suppression is effectively extended to multiple wavelengths, achieving frequency noise levels of 0.71 Hz²/Hz at 10 Hz and 39 Hz²/Hz at 1 Hz. This approach eliminates conventional proportional-integral-derivative feedback loops, bypasses the optoelectronic conversion, and enables low-frequency thermal noise locking entirely within the optical domain. This method streamlines the system architecture, reduces energy consumption, and offers a robust solution for high-precision frequency stabilization across a broad spectral range.