Korganbayev Sanzhar, Ayupova Takhmina, Sypabekova Marzhan, Bekmurzayeva Aliya, Shaimerdenova Madina, Dukenbayev Kanat, Molardi Carlo, Tosi Daniele
Opt Express. 2018 Jul 9;26(14):18708-18720. doi: 10.1364/OE.26.018708.
In this work, a partially etched chirped fiber Bragg grating (pECFBG) is introduced, as a compact sensor for multi-parametric measurement of temperature, thermal gradients over the active length, and refractive index. The sensor is fabricated by wet-etching a portion of a 14-mm linearly chirped FBG with linear chirp profile. The resulting device has two active areas: the unetched part of the grating (2 mm) can be used either as a uniform temperature sensor, or to detect thermal gradients experienced through the grating length by means of a spectral reconstruction technique; the etched part (12 mm), besides having a similar thermal sensitivity, is exposed to refractive index sensing through the introduction of a sensitivity to external refractive index. Overall, the pECFBG structure behaves as a compact sensor with multi-parameter capability, that can both measure temperature and refractive index on the same grating, but also spatially resolve temperature detection through the grating section. The results have been validated through both a model and experimental setup, showing that the mutual correlation algorithm applied to different spectral parts of the grating is able to discriminate between uniform and gradient-shaped temperature profiles, and refractive index changes.
在这项工作中，引入了一种部分蚀刻啁啾光纤布拉格光栅（pECFBG），作为一种用于温度、有效长度上的热梯度和折射率多参数测量的紧凑型传感器。该传感器通过湿法蚀刻一段具有线性啁啾分布的14毫米线性啁啾光纤光栅的一部分来制造。所得器件有两个有源区：光栅的未蚀刻部分（2毫米）既可以用作均匀温度传感器，也可以通过光谱重建技术检测光栅长度上经历的热梯度；蚀刻部分（12毫米）除了具有类似的热灵敏度外，还通过引入对外界折射率的灵敏度来进行折射率传感。总体而言，pECFBG结构表现为一种具有多参数能力的紧凑型传感器，它既能在同一光栅上测量温度和折射率，还能在光栅截面空间分辨温度检测。通过模型和实验装置对结果进行了验证，结果表明应用于光栅不同光谱部分的互相关算法能够区分均匀和梯度形状的温度分布以及折射率变化。
