Chen Qi, Wang D N, Feng Gao, Wang Q H, Niu Y D
Opt Lett. 2020 Nov 15;45(22):6186-6189. doi: 10.1364/OL.411236.
A parallel structured optical fiber Fabry-Perot interferometer sensor is proposed and demonstrated for refractive index and strain sensing with low temperature cross sensitivity. The device consists of two Fabry-Perot cavities fabricated by a femtosecond laser: one is inscribed in the fiber surface waveguide and used for sensing, and the other one is located in the fiber core for referencing. Part of the light propagating in the fiber core can be directed to the fiber surface waveguide via an coupler. Because of the evanescent field, the light traveling along the fiber surface waveguide interacts with the surrounding medium and enables external refractive index sensing. The measurement sensitivity of the device is enhanced due to the Vernier effect associated with the parallel structured two Fabry-Perot interferometers. The sensitivities of ∼843.3/ and ∼101.8/µε have been obtained for refractive index and strain, respectively, and the corresponding temperature cross sensitivities are ∼9.6×10/ and ∼7.956×10µε/, respectively. The device is featured with high robustness, compact size, and large sensitivity.
提出并演示了一种平行结构的光纤法布里-珀罗干涉仪传感器，用于具有低温交叉灵敏度的折射率和应变传感。该器件由两个由飞秒激光制造的法布里-珀罗腔组成：一个刻写在光纤表面波导中用于传感，另一个位于光纤芯中用于参考。在光纤芯中传播的部分光可以通过耦合器被引导到光纤表面波导。由于倏逝场，沿着光纤表面波导传播的光与周围介质相互作用，从而实现外部折射率传感。由于与平行结构的两个法布里-珀罗干涉仪相关的游标效应，该器件的测量灵敏度得到了提高。对于折射率和应变，分别获得了约843.3/和约101.8/με的灵敏度，相应的温度交叉灵敏度分别约为9.6×10/和约7.956×10με/。该器件具有高鲁棒性、紧凑尺寸和高灵敏度的特点。
