Bekmurzayeva Aliya, Shaimerdenova Madina, Tosi Daniele
Annu Int Conf IEEE Eng Med Biol Soc. 2018 Jul;2018:4289-4292. doi: 10.1109/EMBC.2018.8513240.
We discuss the fabrication and interrogation of a fiber-optic refractive index sensors based on wet-etched fiber Bragg grating (EFBG). The fabrication is based on chemical etching of an FBG through an HF-free etching solution (ammonium fluoride and sulfuric acid), which progressively depletes the fiber cladding exposing the core to the outer medium. Microscope inspection of the fiber and real-time detection of the Bragg wavelength allow controlling the sensitivity. The proposed interrogation method is based on a spline interpolation, that measures the change of Bragg wavelength when the FBG is exposed to variations of the refractive index in the surrounding medium. An experimental validation has been carried out, for small refractive index variations (up to $1.85\times 10^{-3}$ RIU), in order to verify the progressive change of sensitivity through fiber etching. The proposed EFBG sensing unit is a building block for functionalized fiber optic biosensors.
我们讨论了基于湿法刻蚀光纤布拉格光栅（EFBG）的光纤折射率传感器的制造与检测。制造过程基于通过无氢氟酸蚀刻溶液（氟化铵和硫酸）对光纤布拉格光栅进行化学蚀刻，该蚀刻溶液会逐渐消耗光纤包层，使纤芯暴露于外部介质。通过显微镜对光纤进行检查以及对布拉格波长进行实时检测，可以控制传感器的灵敏度。所提出的检测方法基于样条插值法，该方法在光纤布拉格光栅暴露于周围介质折射率变化时测量布拉格波长的变化。为了验证通过光纤蚀刻灵敏度的逐渐变化，针对小折射率变化（高达$1.85\times 10^{-3}$RIU）进行了实验验证。所提出的EFBG传感单元是功能化光纤生物传感器的一个构建模块。
