正交解调Pound-Drever-Hall激光稳频系统设计  

Design of Pound-Drever-Hall Laser Frequency Stabilization System Using the Quadrature Demodulation

作　　者：苏娟[1,2] 焦明星[1] 马源源[1] 邢俊红[1] 

机构地区：[1]西安理工大学机械与精密仪器工程学院精密仪器系,陕西西安710048 [2]西安石油大学光电油气测井与检测教育部重点实验室,陕西西安710065

出　　处：《中国激光》2016年第3期244-249,共6页Chinese Journal of Lasers

基　　金：国家自然科学基金(51175421;61205135)

摘　　要：分析了传统Pound-Drever-Hall(PDH)激光稳频方法的工作原理,设计了一种基于正交解调原理的PDH激光稳频方案。该方案采用直接数字频率合成器同时产生两路频率均为10 MHz的正弦和余弦信号,其中正弦信号分为两路:一路用于驱动电光相位调制器以产生相位边带,另一路与余弦信号一起作为相位解调的参考信号。经相位调制后的激光束耦合进入F-P参考腔,所产生的光外差干涉信号由光电探测器进行探测,其输出信号分别与两路正交参考信号进行混频,经低通滤波后得到误差信号的两个正交分量,二者经A/D转换后进入微处理器进行正交相敏检波运算,即可得到PDH稳频系统的误差信号。建立了正交解调PDH激光鉴频实验系统,对F-P参考腔的腔长进行线性扫描,观察到了鉴频曲线,其鉴频灵敏度为1.82 V/MHz,最大频率变化量为5.48 MHz。实验结果表明,所设计的正交解调PDH稳频方案可行。The principle of operation of the traditional Pound-Drever-Hall （PDH） method for laser frequency stabilization is analyzed. Based on the principle of quadrature demodulation, a scheme of PDH laser frequency stabilization is designed, in which both sine and cosine signals with the same frequency of 10 MHz are generated simultaneously by making use of a direct digital synthesizer. The sine signal is divided into two parts, one used to drive an electro-optic modulator to produce the phase sidebands, and the other together with the cosine signal used as the reference signals for the phase demodulation. The phase- modulated laser beams are coupled into the reference Fabry-Perot cavity, and the optical heterodyne interference signal is detected by a photo-detector, whose output is mixed respectively with the two orthogonal reference signals to get the two quadrature components of the error signal after low-pass filtered. By the A/D conversations, the two quadrature components are transmitted to the microprocessor to perform the algorithm of orthogonal phase sensitive detection so that the error signal of the PDH frequency- stabilized system is obtained. A system of the PDH laser frequency discrimination using quadrature demodulation method is established and investigated experimentally, and by linearly sweeping the cavity- length of the reference Fabry-Perot cavity, a curve of frequency discrimination is observed, with a sensitivity of 1.82 V/MHz and a maximum frequency change of 5.48 MHz. Experimental results show that the scheme of the PDH laser frequency stabilization system using the quadrature demodulation method is indeed feasible.

关 键 词：激光器 激光稳频 Pound-Drever-Hall 正交解调 直接数字频率合成器 鉴频曲线 

分 类 号：TN248[电子电信—物理电子学]