弹光调制的频率自跟踪技术  

Self Tracking Technology of Photoelastic Modulation Frequency

作　　者：陈光威 安永泉[1,2] 王志斌[1,2] 陈友华[1,2] 张敏娟[1,2] 王国梁[1] 杨晓[1] 

机构地区：[1]中北大学山西省光电信息与仪器工程技术研究中心,太原030051 [2]中北大学仪器科学与动态测试教育部重点实验室,太原030051

出　　处：《光电工程》2015年第10期21-26,32,共7页Opto-Electronic Engineering

基　　金：国际科技合作项目(2012DFA10680;2013DFR10150);国家自然科学基金仪器专项基金项目(61127015);山西省青年基金项目(2015021084)

摘　　要：弹光调制器会受到自身热耗散影响导致弹光晶体自身温度改变,固有频率随温度漂移引起弹光调制的不稳定和调制效率的降低。针对该问题,本文提出频率自跟踪技术。该方法根据温度对弹光调制系统的影响,建立弹光调制系统的动态模型得到反馈信号与高压驱动信号之间相位差最小对应谐振频率的关系,结合基于FPGA的多通道数字频率和成技术和数学锁相环技术设计并完成了频率自跟踪系统。经实验验证,该设计可实现对频率漂移的跟随,且在驱动信号变化和启动弹光调制器时能自动找到弹光晶体的谐振频率并保持稳定,提高了弹光调制器的稳定性和调制效率。The photoelastic modulator can be affected by its heat dissipation, which induces the change of elasto optical crystal its temperature, natural frequency drift with the temperature caused photoelastic modulation instability and modulation efficiency is decreased. The frequency self tracking technology is presented. According to the effect of temperature on photoelastic modulation system, dynamic model of photoelastic modulation system is established to get the relation between the feedback signal and the high voltage drive signal that the minimum phase difference corresponding resonant frequency. Combined with multichannel Direct Digital Synthesis and Digital Phase Locked Loop technology based on FPGA design, the self frequency tracking system is completed. By experimental verification, the design can achieve the following on the frequency drift, and be able to automatically find elastic optical crystal resonance frequency and remain stable when the drive signal change or start the photoelastic modulator, which improves the stability and modulation efficiency of elastic light modulator.

关 键 词：弹光调制 动态模型 相位差 频率漂移 频率自跟踪 

分 类 号：TN29[电子电信—物理电子学]