中文摘要：

研究了基于细芯光纤内嵌马赫一曾德尔干涉仪的光纤应变传感器，通过将一根细芯光纤熔接在两根单模光纤（sMF）之间，构成了一种光纤内干涉的马赫一曾德尔干涉仪。当单模光纤中的光耦合进细芯光纤时，一部分光耦合进细芯光纤纤芯作为芯模传输，另一部分光耦合进细芯光纤包层中激发出包层模沿包层传输，当芯模和包层模再耦合进单模光纤时发生干涉。当应变作用在细芯光纤上时，干涉条纹发生漂移。通过解调干涉条纹对应变的漂移量实现应变测量，在0~2000με的测量范围下，测得的应变灵敏度为一1．83pm／με，并且实验结果与理论分析有很好的一致性。该传感器具有体积小、制作简单、灵敏度高等优点。

英文摘要：

A optical fiber strain sensor based on in-line Mach-Zehnder interferometer is proposed. The in-line Mach- Zehnder interferometer is fabricated by simply splicing a section of thin-core fiber between two single-mode fibers （SMFs）. When the light couples into the thin-core fiber, part of the light couples into the core of the thin-core fiber and propagates as the core mode. While part of the light couples into the cladding of the thin-core fiber, and many cladding modes are excited. The lights at the core mode and the cladding modes in the thin-core fiber are prone to interference when recoupling into the SMF. By interrogating the wavelength shifts of the interference spectrum, the strain sensor is demonstrated. A strain sensitivity of -1.83 pm/με is achieved within the measurement range from 0 to 2000 με. The experimental results agree well with theoretical analyses. This strain sensor has the advantages of small size, simple fabrication, and high sensitivity.