中文摘要：

研究了微结构光纤（MOF）布拉格光栅（FBG）的双偏振折射率传感特性。利用有限元方法对保偏微结构光纤（PM～MOF）的传输特性进行了分析，计算了传输特性曲线，分析了该种光纤单模传输的范围。同时结合耦合模理论，仿真了该种光纤均匀布拉格光栅在充入不同介质时的反射谱，得到两个偏振模LP61和LPδ1的中心波长差与介质折射率的关系曲线，通过特性曲线拟合出相应公式。同时，仿真了该光纤光栅的温度特性，研究结果表明，两个偏振模中心波长对温度响应相似，因此利用双偏振差分的方式来探测，具有较强的抗干扰能力，这一特性为光纤生物传感器的应用提供了理论依据。

英文摘要：

Refractive index sensing characteristics of a rnicrostructured optical fiber Bragg grating （MOF- BG） based on dual-polarization mechanism are investigated. The finite element method is adopted for calculating the propagation characteristics of a polarization-maintaining MOF. And the single-mode transmission scope is analyzed. Furthermore, the coupled-mode theory is adopted for simulating the reflection spectra of the Bragg fiber grating in the MOF when injecting different media. The relationship between the center wavelength difference of two polarization modes and the refractive index of the medium is analyzed, Ultimately,the corresponding polynomial equation is fitted. Simultaneously, the temperature characteristic of the PM-MOF is also considered. The results demonstrate that the two polarization modes respond similarly to the temperature, and the method based on two polarization center wavelength difference possesses the anti-interference ability. The results provide the theoretical basis for the applications of the PM-MOF Bragg grating in the optical fiber biosensor.