针对高精度测量的要求, 探索性地提出了一种多峰值反射率拟合的解调新方法。讨论了 Levenberg-Marquardt算法在边波带峰值反射率拟合中的应用。根据光纤布拉格光栅对多波长光源的反射作用, 研究光栅反射中心波长与各阶光边波带峰值反射率之间的关系模型, 利用 Lebenberg-Marquardt算法对光栅反射光谱进行特征提取得到特征参量表征传感信息。初步实验证明了该高精度解调方案的有效性和可行性, 并分别获得了 0.1℃的温度分辨率和0.5 με的应变分辨率, 对高精度光栅传感系统的研制具有一定的供参考价值。

Considering the requirement of high accuracy, a novel Fiber Bragg Grating (FBG) modulation method to fit the FBG wavelength with multi-peak reflectivity is proposed. Application of Levenberg-Marquardt algorithm in fitting of peak-reflectivity by sidebands was discussed. The relation model was researched by reflecting central wavelength and peak-reflectivity of sidebands based on the reflex action of FBG for multi-wavelength source. Levenberg-Marquardt algorithm was used to extract the characters from the reflectance spectra to mark sensing information. Temperature resolution 0.1℃ and strain resolution 0.5 με is respectively obtained. The experimental results show that the new method has something referential value to give a guarantee to suit the high accurate measurement with FBG monitoring system.