自映像多模干涉仪的应力传感研究

Optical multimode interferometer based on self-imaging for strain sensing

提出一种基于自映像原理的多模应力传感器。通过测量透射谱中满足自映像条件的波峰波长,解调纵向应力的大小。分析了传感器中多模光纤(MMF)结构参数对透射谱的影响。0～4 400με纵向应力范围的实验结果表明,透射光谱峰值波长的漂移与应力之间呈良好的线性关系,应力敏感度为1.29pm/με。本文传感器制备简单,对MMF的长度精度要求不高。利用多模干涉仪(MMI)的带通特性,可以通过简单地并联不同长度的无芯光纤传感器实现多路复用。

A novel fiber optic multimode strain sensor based on self-imaging effect is presented. The longitudinal strain can be measured by the shift of peak wavelength of transmission spectrum satisfying self-imaging condition. The impact of structure parameters of multimode fiber on the transmission spectrum is analyzed. Experimental results of strain ranging from 0 to 4 400 t;; show a good linear relationship between the strain and the peak wavelength,and the strain sensitivity is 1.29 pm/με. The sensor is easy to fabricate, and the precision requirement of the length of multimode fiber is not too rigorous. Due to the pass-band filter response of multimode interference （MMI） devices, the multiplexing can be easily implemented by the parallel connection of no-core multimode fiber sensors with different lengths.