一种基于光纤光栅法布里-珀罗腔的低频振动传感器

提出了一种基于光纤光栅法布里-珀罗(F-P)腔的低频振动传感方案并进行了理论分析和实验研究。采用单频激光器作为光源,光纤光栅F-P腔通过两点涂胶方式粘接在等强度悬臂梁上,待测振动信号通过支架和悬臂梁将振动作用传至光纤光栅F-P腔,引起腔长周期性变化,从而改变光纤光栅F-P腔的反射光谱特性,通过解调输出光信号的振荡频率和峰值,即可实现对振动信号频率和幅值的测量。利用压电陶瓷模拟的低频振动信号进行了实验验证,测量结果与理论分析相吻合。该传感器测量灵敏度高,特别适用于微弱振动信号的测量。

A Vibration Sensor Based on Fiber Bragg Grating Fabry-Perot Cavity

A sensor solution for weak vibration based on Fiber Bragg Grating Fabry-Perot (F-P) cavity is designed and experimentally demonstrated,in which a laser with single-frequency is used as the light source.The F-P cavity is affixed to the cantilever structure of even distribution of strain along the axis and the pair of fiber Bragg gratings as the cavity reflectors is placed freely.The vibration spreading to fiber grating F-P cavity through the cantilever beam vibration,causes changes in cavity length,thus changing the reflective light intensity of fiber grating F-P cavity.Theoretical analysis indicates that,the amplitudes and frequencies of vibration can be measured by demodulating the peaks and frequencies of the signal.The experimental results of measuring artificial vibration simulated with PZT agree with the theory well.This sensor has high measuring accuracy and can be used for detecting weak vibration.