基于游标效应的可调节光纤应变传感器

Tunable Fiber Optic Strain Sensor Based on Vernier Effect

提出并制备了一种基于法布里-珀罗干涉仪游标效应的高灵敏度光纤应变传感器。该传感器包含两个并联的法布里-珀罗干涉仪,其中,传感干涉仪由单模光纤和一小截毛细石英管熔接构成,参考干涉仪由放置在光纤熔接机中的单模光纤对齐。当两个干涉仪具有相近的自由光谱范围时,利用干涉仪游标效应进一步放大传感干涉仪的应变敏感性。在此基础上,通过简单地调节熔接机改变参考干涉仪腔长,并联结构可以选择不同放大倍数以获得不同灵敏度。实验结果表明,在熔接机的辅助下,在0~250με的应变范围内并联结构的应变灵敏度分别达到22.16 pm/με和32.88 pm/με,比单一结构的灵敏度(5.76 pm/με)分别提高3.84倍和5.70倍。该传感器具备制作简单、灵敏度高、重复性好、操作方便,以及成本低等优点,为应变检测提供了新的思路。

In this paper,a highly sensitive fiber optic strain sensor based on the FabryPerot interferometer vernier effect is proposed and prepared.The sensor consists of two parallel FabryPerot interferometers,where the sensing interferometer consists of a singlemode fiber and a short segment of capillary quartz tube fused together,and the reference interferometer is aligned by a singlemode fiber placed in a fiber fusion machine.When the two interferometers have similar free spectral ranges,the strain sensitivity of the sensing interferometer is further amplified by using the vernier effect.Based on this,the parallel structure can be selected with different magnifications to obtain different sensitivities by simply adjusting the fusion splicer to change the reference interferometer cavity length.The experimental results showed that the strain sensitivity of the parallel structures in the strain range of 0~250μεwith the assistance of the fusion splicer reached 22.16 pm/μεand 32.88 pm/με,which were 3.84 and 5.70 times higher than the sensitivity of the single structure(5.76 pm/με),respectively.The sensor has the advantages of simple fabrication,high sensitivity,good repeatability,easy operation,and low cost,which provides a new idea for strain detection.