基于全光纤Fabry-Perot干涉的差分测振系统设计  

All-fiber Fabry-Perot Interference Vibration Measurement Differential System

作　　者：梁洪卫[1] 刘冬冬[1] 阚玲玲[1] 苏皓 LIANG Hongwei;LIU Dongdong;KAN Lingling;SU Hao(School of Electrical Engineering&Info.,Northeast Petroleum Univ.,Daqing 163318,China)

机构地区：[1]东北石油大学电气信息工程学院,黑龙江大庆163318

出　　处：《工程科学与技术》2021年第5期214-218,共5页Advanced Engineering Sciences

基　　金：东北石油大学国家基金培育基金项目(2018GPYB-03);黑龙江省自然科学基金项目(LH2020F005)。

摘　　要：一般光路中传输信号存在光功率影响、外界振动干扰、光路本征噪声和环境温度变化引起的热运动影响,并且光纤对环境干扰极其敏感,任何环境的扰动都会带来相应的相位误差;同时,如果对信号进行预处理滤波,容易导致一些微小信息丢失,增大重构误差。针对微米级振动测量中内部共模噪声影响测量精度且增大重构误差的问题,建立了一种基于全光纤Fabry–Perot(F–P)干涉的差分测量系统。首先,根据F–P干涉原理的相位方程及2×2单模光纤耦合器在传输过程中直通臂和耦合臂具有90°的相位差特性,通过推导得到结构中两输出端探测器接收的信号大小相等、方向相反。然后,经两信号做差可以增大总体信号幅值,削弱共模噪声对信号的影响,增强信号质量。通过实验对干涉信号进行重构位移分析,实验结果表明:在镜面2μm正弦振动中,合成信号的最大重构误差降低了0.4%;在粗糙表面1.4μm振动测量下,重构误差降低了2.8%;差分结构能降低测振重构误差,重构波形更加平缓。Generally,the noise transmitted in the optical path mainly includes the influence of optical power,external vibration interference,the intrinsic noise of the optical path,and the influence of thermal motion caused by environmental temperature changes.The optical fiber is extremely sensitive to environmental interference,and any environmental disturbance will bring corresponding phase errors.At the same time,if the signal is preprocessed and filtered,it is easy to cause some small information to be lost and increase reconstruction errors.Aiming at the problem of internal common mode noise affecting measurement accuracy and increasing reconstruction error in micron-level vibration measurement,a differential measurement system based on all-fiber Fabry–Perot(F–P)interference is established.Firstly,according to the phase equation of the F–P interference principle and the 2×2 single-mode fiber coupler during the transmission process,the through arm and the coupling arm have a phase difference of 90°.It is deduced that the signals received by the two output detectors are equal in amplitude and opposite in direct.Then the difference between the two signals can increase the overall signal amplitude,weaken the influence of common mode noise on the signal,and enhance the signal quality.Through the reconstruction displacement analysis of the interference signal,the experimental results show that the reconstruction error of the synthesized signal is reduced by 0.4%in the 2μm sinusoidal vibration of the mirror.Under 1.4μm vibration measurement on rough surface,the reconstruction error is reduced by 2.8%.The experimental results also show that the differential structure can reduce the vibration measurement reconstruction error,and the reconstructed waveform is smoother.

关 键 词：激光测振 法布里–玻罗干涉 差分系统 消噪 

分 类 号：TN249[电子电信—物理电子学]