设计了一种由封闭在光纤内的纺锤型空气腔和其周围的SiO2构成的三明治结构全光纤马赫曾德尔干涉仪, 并将其用于应变传感。纺锤型空气腔利用光子晶体光纤和普通单模光纤熔接后再拉锥形成。由于干涉仪的两个干涉臂介质为空气和SiO2, 因此超短的干涉臂长使光传输损耗大大降低, 构成了超紧凑马赫曾德尔干涉仪。该干涉仪用于应变传感可大大减小弯曲带来的串扰, 提高系统的稳定性。建立了超紧凑马赫曾德尔干涉仪模型, 基于FDTD算法对干涉仪输出的干涉条纹以及各部分的电场分布进行了仿真, 得到了应变传感器干涉条纹波谷波长与应变的关系, 为设计制作超紧凑全光纤马赫曾德尔应变传感器提供了理论依据。

A sandwichstructured allfiber MachZehnder interferometer with sealed spindletype air cavity and the surrounded SiO2 was designed and used for strain sensing. The spindletype air cavity was manufactured by splicing and taper a photonic crystal fiber and a singlemode fiber. The media of two interference arm are air and SiO2, so the ultra short interference arm length greatly reduces the loss of optical transmission. The interferometer is used in strain sensing to greatly reduce the crosstalk caused by bending and improves the stability of the system. The ultracompact MachZehnder interferometer model is established, and the interference fringes output by the interferometer and the electric field distribution of each part are simulated based on the FDTD algorithm. The relationship between the wavelength and the strain is simulated, which provides a theoretical basis for the design of ultracompact allfiber MachZehnder strain sensor.