Wei Yong, Li Lingling, Liu Chunlan, Wang Rui, Zhao Xiaoling, Ran Ze, Ren Zhuo, Jiang Tianci
Opt Express. 2022 Feb 28;30(5):7412-7425. doi: 10.1364/OE.449091.
How to couple the light in the fiber core to the cladding is an urgent issue that need to be done for the fabrication of the fiber-cladding SPR sensor, and there is no report about the fiber SPR strain sensor. Hereby, we propose and demonstrate a high sensitivity fiber cladding SPR strain sensor based on V-groove structure. By CO laser, the V-groove is fabricated on the single-mode fiber, and the light in the fiber core is effectively coupled to the cladding. The cladding 2cm behind the V-groove is coated with sensing gold film, and a multimode fiber is spliced with the sensing probe to construct the novel fiber cladding SPR sensor. On the basis of the investigation of the effects of different V-groove depth, number and period on the performance of fiber SPR refractive index sensor, a high sensitivity strain SPR sensor is designed and fabricated by employing the characteristic that the V-groove will deform with strain. The testing results indicate that the average refractive index sensitivity of the sensor is 2896.4nm/RIU, and the strain wavelength sensitivity is 25.92pm/µε which is much higher than that of the fiber interference and grating strain sensors, and the strain light intensity sensitivity is -4.4×10 a.u./µε. The proposed fiber cladding SPR strain sensor has the advantages of simple structure and convenient manufacture, and can be used for working in a narrow space.
如何将光纤纤芯中的光耦合到包层是制造光纤包层表面等离子体共振（SPR）传感器时亟待解决的问题，且目前尚无关于光纤SPR应变传感器的报道。在此，我们提出并展示了一种基于V型槽结构的高灵敏度光纤包层SPR应变传感器。通过CO激光在单模光纤上制备V型槽，使纤芯中的光有效地耦合到包层。在V型槽后方2cm处的包层上涂覆传感金膜，并将多模光纤与传感探头熔接以构建新型光纤包层SPR传感器。在研究不同V型槽深度、数量和周期对光纤SPR折射率传感器性能影响的基础上，利用V型槽会随应变发生形变的特性，设计并制作了一种高灵敏度应变SPR传感器。测试结果表明，该传感器的平均折射率灵敏度为2896.4nm/RIU，应变波长灵敏度为25.92pm/με，远高于光纤干涉和光栅应变传感器，应变光强灵敏度为-4.4×10 a.u./με。所提出的光纤包层SPR应变传感器具有结构简单、制造方便的优点，可用于在狭窄空间中工作。
