中文摘要：

提出一种结构简单且灵敏度高的液体封装结构光纤马赫-曾德干涉仪（MZI）温度传感器,并对其折射率和温度响应特性进行了理论分析和实验研究。3段单模光纤（SMF）采用锥腰扩大熔接技术顺次熔接构成同轴式光纤MZI,结果表明MZI对环境折射率非常敏感；然后,将MZI封装在充满Cargille液体的毛细管中,结果表明液封后的MZI在测试温度范围内（10～40℃）的灵敏度约150pm/℃,较之封装前提高了1倍,且远高于大多数的光纤光栅和其它光纤干涉仪型温度传感器。本文MZI温度传感器还具有良好的物理强度和易于制备等优点,在环境监测和食品工业等领域具有良好的应用前景。

英文摘要：

A simple and highl y sensitive fiber in-line Mach-Zehnder interferometer （MZI） temperature sensor is demonstrated,its responses to surrounding refractive index and temperature are analyzed theoretically and expe rimentally,and especially the different mechanisms of the fiber MZI before and after sealing are compared for temperature sensing.The interferometer is realized by splicing three t elecom single-mode fibers with large “overlap” splicing parameters to form two waist-enlarged fusion bitaper s.Experimental results show that the MZI is sensitive to surrounding refractive index （RI）.Then the MZ I is sealed in a capillary tube filled with Cargille oil.Due to the thermo-optic effect of sealing-liqui d and the intrinsic high RI sensitivity of the interferometer,the sensor produces a very high temperature s ensitivity of 150pm/℃ within the range of 10-40℃.The sensitivity is double times of that of the bar e MZI in air and it is much higher than that of some fiber grating-based sensors or fiber in-line interferometric sensors.Moreover,the proposed sensor has advantages of low cost,easy-to-fabrication and good physical stren gth,which makes it promising in environmental monitoring,food industry,and other fields for temperature sensing.