基于光纤干涉仪的振动测量技术

Vibration measurement based on optic fiber interferometer

本文介绍了基于光纤Mach-Zehnder干涉仪的振动测量系统,用线阵CCD测量条纹动态位移,实现了光纤干涉条纹图像的连续采集。针对干涉条纹图像噪声的特点完成了低通滤波器的设计、图像的平滑处理,消除了干涉条纹中心的定位误差。文章绘制了干涉条纹位移曲线并对其进行了离散傅里叶变换,给出了所测振动的频谱特性。最后讨论了测量系统的灵敏度以及影响测量精度的因素,为了能够辨别条纹的移动方向,指出了条纹最大允许的移动速度限制,给出了实验结果。

A vibration measurement system based on optic fiber Mach-Zehnder interferometer was introduced. A linear CCD was used to measure the displacement of interferometer fringes. The continuous capture of interference fringes was realized, The design of low-pass filter and image smoothing were finished according to the characteristics of interference fringes. Orientation error of interference fringe center was removed, Displacement curve of fringe center was drawn and the spectrum of the displacement was analyzed with Discrete Fourier Transform （DFT）, Finally, the factors affecting maximal permissible movement speed of interference fringe and accuracy of measurement were also discussed, For the purpose of distinguishing shift direction of fringes, the max shifting speed-allowed limitation was given.