基于内调制的光纤干涉振动测量系统研究  

Research on fiber optic interferometric vibration measurement system based on internal modulation

作　　者：贾鹏 谢建东[1] 楼盈天[1] 杨晔[1] 杨涛[1] Jia Peng;Xie Jiandong;Lou Yingtian;Yang Ye;Yang Tao(Precision Measurement Laboratory,Zhejiang Sci-Tech University,Zhejiang,Hangzhou 310018,China)

机构地区：[1]浙江理工大学精密测量技术实验室,浙江杭州310018

出　　处：《光电工程》2025年第1期10-22,共13页Opto-Electronic Engineering

基　　金：国家重点研发计划(2022YFF0705803);浙江理工大学科研基金(11122932612222,23222133-Y)。

摘　　要：研制了一种基于内调制的光纤干涉振动测量系统。对分布式反馈激光器(DFB)进行电流内调制,产生正弦频率调制单频激光。经光纤环形器与光纤微探头输出测量光对振动源进行干涉测量,返回的测量光与光纤微探头自反射的参考光进行干涉获得相位生成载波(PGC)干涉信号。基于可编程逻辑门阵列(FPGA)数字信号处理平台设计了PGC干涉信号解调算法,通过5参数椭圆拟合提取附加光强调制等因素引入的误差系数,对相位非线性误差进行补偿,实现振动位移的高精度测量,并采用快速傅里叶变换(FFT)算法对振动位移频谱进行分析。进行了理论分析并搭建了振动测量系统,开展了干涉信号解调实验、位移测量实验和振动测量实验。实验结果表明,该系统的振动频率范围覆盖1142 Hz;在10μm的位移步进实验中,测量结果的平均偏差为0.173μm;振动频率的分辨力为1.221 Hz,谐波失真率小于1.36%;有望应用于精密振动测量领域。A fiber microprobe vibration measurement system based on internal modulation has been developed.A sinusoidal phase modulated laser source is generated by modulating the current of the distributed feedback laser(DFB)with a sinusoidal signal.After passing through a fiber circulator and a fiber microprobe,the output laser beam is used to measure the displacement of a vibration source.The returned laser beam interferes with the reference laser reflected by the fiber microprobe to generate a phase generated carrier(PGC)interference signal.A real-time PGC signal processing algorithm is designed through a programmable logic gate array(FPGA)digital computing platform.A five-parameter ellipse fitting method is unitized to extract the error items introduced by additional intensity modulation and other factors and compensate for the phase nonlinear error.The fast Fourier transform(FFT)algorithm is unitized to analyze the vibration displacement.Theoretical analysis was conducted and a vibration measurement system was built.A series of experiments were conducted,including PGC signal demodulation,displacement measurement,and vibration measurement.The experimental results show that the vibration frequency range of the system covers 1142 Hz.In the 10μm step displacement experiment,the average deviation measured is 0.173μm.The resolution of vibration measurement is 1.221 Hz,and the harmonic distortion is less than 1.36%.The measurement system is expected to be applied in the field of precise vibration measurement.

关 键 词：振动测量 内调制 微探头 相位生成载波 椭圆拟合 

分 类 号：TN249[电子电信—物理电子学]