基于匹配光纤光栅法布里-珀罗干涉仪的应变解调方法

提出并实验验证了一种基于匹配光纤光栅法布里-珀罗干涉仪的应变传感器解调方法,该方法综合了光纤法布里-珀罗干涉技术和匹配光纤光栅滤波法的优点.通过半导体制冷片和压电陶瓷组成的闭环负反馈控制系统,精确调节匹配光栅法布里-珀罗干涉仪的温度和应变,有效解决了光栅法布里-珀罗干涉仪的失配问题,从而保证系统静态工作点处于最佳匹配位置,同时能够避免探头因环境温度波动导致的测量误差.实验结果表明,该系统能够响应50~800 Hz的输入信号,应变最小分辨力至少为0.4 nε/Hz^1/2,解调灵敏度高,且不受环境温度波动的影响,因而在动态应变或振动测量中具有较高的实用性.

Strain Demodulation Method Based on Matched Fiber Bragg Grating Fabry-Perot Interferometer

A novel demodulation method based on matched Fiber Bragg grating Fabry-Perot interferometer (FBG-FPI) for strain measurement is proposed and demonstrated, which combines the advantages of fiber Fabry-Perot interferometry and matched fiber Bragg grating filtering technique. In order to solve the mismatch problem and keep the static working point at the best matching position, the strain and temperature of the matched FBG-FPI are adjusted by a closed-loop control system consisted of the semiconductor refrigeration and piezoelectric ceramic. Meanwhile, the system is immune to the surrounding temperature. Experimental results show that the system can respond to the input signal with the frequency range of 50~800 Hz, is insensitive to the temperature fluctuation, and the strain resolution is up to 0.4 nε/Hz^1/2. Therefore, this method has a higher practicality for dynamic strain monitoring and vibration measurement.