Campanella Carlo Edoardo, Mastronardi Lorenzo, De Leonardis Francesco, Malara Pietro, Gagliardi Gianluca, Passaro Vittorio M N
Opt Express. 2014 Oct 20;22(21):25371-84. doi: 10.1364/OE.22.025371.
In this paper, we report on theoretical investigation of split mode resonant sensors based on fiber Bragg grating (FBG) ring resonators and π-shifted fiber Bragg grating (π-FBG) ring resonators. By using a π-shifted Bragg grating ring resonator (π-FBGRR) instead of a conventional fiber Bragg grating ring resonator (FBGRR), the symmetric and antisymmetric resonance branches (i.e., the eigen-modes of the perturbed system) show peculiar and very important features that can be exploited to improve the performance of the fiber optic spectroscopic sensors. In particular, the π-FBGRR symmetric resonance branch can be taylored to have a maximum splitting sensitivity to small environmental perturbations. This optimal condition has been found around the crossing points of the two asymmetric resonance branches, by properly choosing the physical parameters of the system. Then, high sensitivity splitting mode sensors are theoretically demonstrated showing, as an example, a strain sensitivity improvement of at least one order of magnitude over the state-of-the-art.
在本文中，我们报告了基于光纤布拉格光栅（FBG）环形谐振器和π相移光纤布拉格光栅（π-FBG）环形谐振器的分裂模式谐振传感器的理论研究。通过使用π相移布拉格光栅环形谐振器（π-FBGRR）代替传统的光纤布拉格光栅环形谐振器（FBGRR），对称和反对称谐振分支（即受扰系统的本征模式）呈现出特殊且非常重要的特性，可用于提高光纤光谱传感器的性能。特别是，π-FBGRR对称谐振分支可以被调整为对小的环境扰动具有最大的分裂灵敏度。通过适当选择系统的物理参数，已在两个非对称谐振分支的交叉点附近发现了这种最佳条件。然后，从理论上证明了高灵敏度分裂模式传感器，例如，与现有技术相比，其应变灵敏度提高了至少一个数量级。
