聚合物封装的光纤光栅压力传感器的特性研究

Research on characteristics of fiber grating-based pressure sensor using polymer packaging

为了改善现有光纤压力传感器灵敏度低、封装结构复杂等问题,提出一种基于聚合物封装的光纤布拉格光栅压力传感器。选取聚合物压力增敏材料聚碳酸酯、聚乙烯和环氧树脂对裸光纤光栅进行嵌入式封装。基于全矢量有限元法,利用COMSOL对聚合物封装的光纤光栅压力传感器的应变特性进行仿真分析,得到器件长度的总位移变化量,利用MATLAB分析其中心波长随压力的变化关系。仿真实验表明,聚碳酸酯、聚乙烯和环氧树脂3种压力敏感封装材料中,采用聚碳酸酯聚合物的应变响应灵敏度系数最佳,传感器的压力灵敏度可达-3.89×10^-4/MPa,相较于裸光纤光栅提高约200倍,机械强度高,可长效作业,适用于深海强压力测量等特殊工程环境。

A design of fiber Bragg grating(FBG)sensor in a polymer package is proposed.In order to enhance existing fiber sensor,which has low sensitivity and complicated packaging structures.The choices of package material,including polycarbonate,polyethylene and epoxy resin,are considered and optimized to promote maximum pressure sensitivity of FBG sensor.Based on full vector finite element method,the strain characteristics of polymer encapsulated FBG sensor are simulated and analyzed by COMSOL,and the total displacement variation of the device length is obtained.Furthermore,the relationship between central reflection wavelength and pressure is analyzed by MATLAB.The simulation results indicate that among the three materials,polycarbonate is the optimum choice for packaging FBG sensor.This investigation on optimization of polymer packaging parameters gives rise to pressure sensitivity of nearly 200 times as compared with bare FBG sensor,with the numerical values of-3.89×10^-4/MPa for an optimized FBG sensor in polymer packaging.Such high-pressure sensitivity of FBG senior can be considered as initial step toward the realization of a highly sensitive hydrophone based on FBG for sensing underwater acoustic signals.