设计了一种基于光子晶体光纤的双锥形马赫曾德尔干涉仪，并对其折射率传感特性进行了研究。在FDTD Solutions光学仿真平台中建立了干涉仪结构模型，研究了该结构的透射光谱对环境折射率的响应。仿真结果表明，透射光谱随环境折射率的增加发生红移，灵敏度为95.906nm/RIU。利用熔接与拉锥工艺制备了干涉仪样品，搭建了实验系统，在不同浓度甘油溶液中对其透射谱进行了检测，实验结果表明，折射率在1.3222~1.3538范围内，透射谱偏移灵敏度为121.95nm/RIU。该传感器具有体积小、重量轻、易于制备、灵敏度高等优点，适用于生化和物理传感领域。

A biconical MachZehnder interferometer based on photonic crystal fiber is designed, and its refractive index (RI) sensing characteristics are studied. The sensor performance was simulated by FDTD Solutions, and the results show that the transmission spectrum is redshifted with the increasing RI and the sensitivity is 95.906nm/RIU. An experimental platform was built to test the sensor under different concentrations of glycerin solution, and the response relationship between its transmission spectrum and external refractive index was studied. The experimental results show that with RI changing from 1.3222 to 1.3538, the sensitivity is 121.95nm/RIU@1550nm. The RI sensor with the characteristics of high RI sensitivity, easy fabrication and lowcost is suitable for applications in the biochemical and physical sensing fields.