基于PDH的法布里-珀罗腔稳定性研究

Research on Stability of Fabry-Perot Cavity Based on PDH

针对法布里-珀罗(FP)腔对更高稳定性的需求,提出了利用Pound-Drever-Hall(PDH)技术稳定FP腔的方案。根据理论计算模型,详细分析了FP腔谐振光学系统的静态响应与动态响应特性。运用静态分析得到的误差信号可实现FP腔的锁定,动态响应分析得到的频率响应有助于设计控制环路将FP腔稳定在选择的工作点处。数值仿真结果表明,当光学增益为0.785 W/(°),且误差信号为毫瓦量级时,FP腔的长度稳定精度可达4 pm。通过对比FP腔锁定前后反射光的光斑尺寸与形状,验证了该方案的有效性和可行性。

A scheme for stabilizing the Fabry-Perot（FP） cavity based on the Pound-Drever-Hall（PDH） technique is proposed for the need of more stable FP cavity. According to the theoretical calculation model, the static and dynamic response characteristics of the FP cavity resonant optical system are analyzed in details. The error signal obtained by the static analysis can be used to lock the FP cavity, and the frequency response obtained by the dynamic response analysis helps to design a control loop to maintain the FP cavity at the chosen operating point. The numerical simulation results show that when the optical gain is 0.785 W/（°） and the error signal stays at the milliwatt level, the length stability precision of the FP cavity achieves 4 pm. The validity and feasibility of the scheme are verified by comparing the beam spot size and shape of the reflected light before and after the FP cavity locking.