提出了一种基于光纤锥的在线型光纤马赫曾德干涉仪式折射率传感器.传感器是在一根单模光纤上使用光纤熔接机拉制出两个光纤锥，光纤锥的直径为43.7 μm，长度为480 μm.干涉仪中光纤锥充当光纤耦合器，激发出光纤高阶模，并将高阶模耦合进单模光纤使之与纤芯基模形成模间干涉.被环境溶液的折射率、温度的变化改变模式间相位差，将导致干涉仪的传输光谱发生漂移，从而实现传感测量.实验结果表明：当环境溶液的折射率变化范围为1.335~1.403RIU时，传感器的折射率灵敏度为－128.233 nm/RIU；当水溶液的温度变化范围为30~75℃时，传感器的温度灵敏度为0.111 nm/℃.该传感器具有制作方法简单、灵敏度高、成本低等特点，可应用于生物传感测量.

A kind of infiber MachZehnder interferometer based on fiber taper was proposed. The sensor is formed by cascaded two fusion tapers in singlemode fiber through a fusion splicer. The fiber taper has a diameter of 43.7 μm and length of 480 μm. The fiber taper acts as couplers, it could not only excite the highorder modes, but also couple these modes into singlemode fiber to form the intermodal interference. When surrounding refractive index and temperature of the surrounding liquid changes, the intermodal phase difference changes. Through monitoring the transmission spectrum of the interferometer, the refractive index and temperature were determined. The experimental results show that the sensor sensitivity is －128.33 nm/RIU in the RI range of 1.335~1.403RIU, and the temperature sensitivity is 0.111nm/℃ in the water temperature range of 30~75℃. The sensor has advantages of easy fabrication, high sensitivity, and inexpensive, which has a potential in biological sensing.