基于光波导理论和传输矩阵法, 研究了光纤Bragg光栅(FBG)折射率传感器在非均匀液相介质下的响应特性。在数值计算中, 分别考虑高折射率区(1.42～包层折射率)和低折射率区(1.33～1.36)两种情况, 并假设非均匀液相介质的折射率分布为线性函数, 仿真结果表明, FBG的反射谱特性强烈依赖于介质折射率分布函数的某些特征参数, 比如折射率沿FBG轴向的分布梯度、折射率在FBG两端的差值。研究结果对FBG折射率传感器在生化传感中的应用具有一定意义。

Based on the fiber waveguide theory and the transfer matrix method, the responsive characteristics of the fiber Bragg grating (FBG) refractive index sensors under uneven liquid medium were analyzed in detail. Tow surrounding refractive index (SRI) ranges, including the high SRI region (from 1.42 to the fiber cladding index) and the low ones (from 1.33 to about 1.36), were considered. Numerical results show that the responsive characteristics of the reflectance spectrum of the FBG refractive index sensor were closely related to the properties of the refractive index distribution, such as the refractive index gradient and the Dvalue of the SRI at both its ends. The research results are meaningful for the applications of FBG refractive index sensors in biochemical sensing fields.