基于互相关的电光调制器相位标定方法  

Phase Calibration Method of Electro-Optic Modulator Based on Cross-Correlation

作　　者：何恩兴 陈友华[1] 谢舜宇 匡翠方[1] He Enxing;Chen Youhua;Xie Shunyu;Kuang Cuifang(State Key Laboratory of Modern Optical Instrumentation,College of Optical Science and Engineering,Zhejiang University,Hangzhou 310027,Zhejiang,China)

机构地区：[1]浙江大学光电科学与工程学院现代光学仪器国家重点实验室,浙江杭州310027

出　　处：《光学学报》2023年第23期82-88,共7页Acta Optica Sinica

基　　金：国家重点研发计划(2021YFF0700302);国家杰出青年科学基金(62125504);国家自然科学基金(61975188);浙江省自然科学基金(LY23F050010,LQ23F050010)。

摘　　要：为了在使用相位电光调制器前能够快速准确地确定其半波电压,提出了一种基于频域互相关的干涉条纹相位差计算方法用于相位电光调制器的标定。该方法将条纹图像通过傅里叶变换转换成频谱图并对其进行滤波,将提取出的正负一级次频谱信息进行互相关操作,得到两张条纹图之间的相位差。为了验证所提方法在相位电光调制器标定中的作用,搭建实验系统,使得一路经过电光调制器的光与另一路光进行干涉后形成条纹像,改变电光调制器上施加的电压并用相机记录相位不同的干涉条纹,从而获得干涉条纹组,进而运用所提方法获得相位-电压对应关系。与轮廓法相比,所提方法快速且精度高。与迈克耳孙干涉法相比,该方法不需要重新搭建光路,操作迅速且能够达到相当的精度。Objective Electro-optic modulators can change the phase and polarization state of incident light,therefore having a wide range of applications in many fields,such as optical communication,integrated optics,and super-resolution microscopy.They feature fast response and reliability.However,due to the differences among electro-optic modulator devices,the relationship between the applied voltage and the phase change in actual operation is not consistent with the corresponding relationship in the technical manuals.Meanwhile,when modulators are working at different wavelengths,applying the same voltage to the modulator results in different phase changes.Therefore,before utilization,it is necessary to calibrate the relationship between the phase change and voltage change of the electro-optic modulator.Since its modulation is linear,the slope of the function only needs to be obtained for subsequent experiments.Common calibration methods include the contour method and the Michelson interferometry method.The contour method employs two optical paths for interference,one of which passes through an electro-optic modulator to change the phase.Interference fringes are taken at a certain voltage interval.The displacement between two fringes is divided by the fringe period and then multiplied by 2πto obtain the phase difference which is combined with the voltage interval to get the half-wave voltage.This method is simple but requires repeated adjustment and correction,which is time-consuming and laborious.Additionally,the limitation of camera pixels reduces the accuracy.The Michelson interferometry method passes one of the interferometer arms through an electro-optic modulator,applies a voltage to produce a phase shift,and then moves this arm to change the optical path difference and make the interference fringes disappear to determine the phase difference.This method has high accuracy but requires optical path rebuilding with too much consumed time.To quickly and accurately calibrate the half-wave voltage of an electro-optic mo

关 键 词：傅里叶光学 信号处理 频谱分析 相共轭 互相关 电光调制器 

分 类 号：O436[机械工程—光学工程]