为建立稳定的光纤光栅传感器波长解调系统,利用可调谐法布里-珀罗滤波器的窄带滤波特性实现对宽带光源的线性扫描,采用放在恒温箱的高精度参考光栅标定法布里-珀罗标准具的方法,提供多个间隔相同、幅值平稳的波长参考点。将采集到的原始数据序列采用改进的小波阈值去噪算法(使用新的阈值函数和阈值)进行平滑滤波处理,通过高斯拟合算法的核心思想得到粗峰值序列,再进行二次处理,去掉无效峰,修正部分峰的位置,搭建了光纤光栅位移传感器的实时监测解调系统,与螺旋测微仪相比精度稳定在0.25 mm左右。

In order to establish a stable fiber grating sensor wavelength demodulation system, we use narrow band filter characteristic of tunable Fabry-Perot filter to make a linear scan of broadband light source, and use a high-precision reference grating placed in a thermostat to calibrate Fabry-Perot etalon, and to provide multiple wavelength reference points with the same interval and stable amplitude. The original data sequence is modified by the improved wavelet threshold denoising algorithm(using a new threshold function and a new threshold). We gain raw peak sequence by the core idea of the Gaussian fitting algorithm, and then do the secondary treatment, remove some invalid peaks, modify location of part peaks, and build a fiber grating displacement sensor real-time monitoring and demodulation system. Compared with spiral micrometer, accuracy of this system is about 0.25 mm.