基于拉锥光纤布拉格光栅的法布里-珀罗应变传感器的仿真研究

Simulation of Fabry-Perot strain sensor based on tapered fiber Bragg grating

为解决干涉型光纤应变传感器自由光谱范围较小或干涉条纹精细度较低等问题,提出了一种基于单拉锥光纤布拉格光栅的法布里-珀罗腔的应变传感结构及其改进方案。利用啁啾光纤布拉格光栅不同位置反射不同波长的特性,形成腔长随波长连续变化的法布里-珀罗腔,得到了无穷大的自由光谱范围且谐振谷精细度高。数值计算结果表明,应变传感灵敏度与拉锥光纤的腰区直径和栅区长度正相关。在0~300με范围内,当腰区直径为光纤直径的3/25,栅区长度为30 mm时,应变传感灵敏度为7.05 pm/με。该结果对其他干涉型传感结构的设计具有一定的参考价值。

In order to solve the problems of small free spectrum range or low interference fringe fineness,a strain sensing structure and its improved scheme of Fabry-Perot cavity based on single tapered fiber Bragg grating was proposed.By utilizing the characteristic of reflecting different wavelengths at different positions of the chirped fiber Bragg grating,the Fabry-Perot cavity was formed with a continuous variation of cavity length with wavelength,and the infinitely-great free spectrum range as well as the high resonance valley fineness was obtained.Numerical results show that the strain sensing sensitivity is positively related with the lumbar region diameter and grating region length of tapered fiber.In the range of 0~300με,the strain sensing sensitivity is obtained to be 7.05 pm/μεwhen the lumbar region diameter is 3/25 of the fiber diameter and the grating region length is 30 mm.The results have some reference value for the design of other interferometric sensing structures.