Asymmetrical Fabry-Perot cavity slot micro-ring resonator and its sensing characteristics  

非对称法布里⁃珀罗腔槽型微环谐振器及其传感特性

作　　者：CAO Qianqian LIU Chunjuan WU Xiaosuo SUN Xiaoli 曹倩倩;刘春娟;吴小所;孙晓丽(兰州交通大学电子与信息工程学院,甘肃兰州730070)

机构地区：[1]School of Electronic and Information Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China

出　　处：《Journal of Measurement Science and Instrumentation》2024年第3期292-301,共10页测试科学与仪器（英文版）

基　　金：supported by Natural Science Foundation of Gansu Province(No.22JR5RA320).

摘　　要：To achieve high quality factor and high-sensitivity refractive index sensor,a slot micro-ring resonator(MRR)based on asymmetric Fabry-Perot(FP)cavity was proposed.The structure consisted of a pair of elliptical holes to form an FP cavity and a microring resonator.The two different optical modes generated by the micro-ring resonator were destructively interfered to form a Fano line shape,which improved the system sensitivity while obtaining a higher quality factor and extinction ratio.The transmission principle of the structure was analyzed by the transfer matrix method.The transmission spectrum and mode field distribution of the proposed structure were simulated by the finite difference time domain(FDTD)method,and the key structural parameters affecting the Fano line shape in the device were optimized.The simulation results show that the quality factor of the device reached 22037.1,and the extinction ratio was 23.9 dB.By analyzing the refractive index sensing characteristics,the sensitivity of the structure was 354 nm·RIU−1,and the detection limit of the sensitivity was 2×10−4 RIU.Thus,the proposed compact asymmetric FP cavity slot micro-ring resonator has obvious advantages in sensing applications owing to its excellent performance.为实现高品质因子和高灵敏度的折射率传感器,提出了一种基于非对称法布里-珀罗(Fabry-Perot,FP)腔的槽型微环谐振器(Micro-ring resonator,MRR)。该结构中,一对椭圆形孔构成的法布里-珀罗腔与微环谐振器形成两种不同的光模式,因破坏性干涉而形成Fano线型,由此获得了较高品质因子和消光比,提高了系统灵敏度。利用传输矩阵法分析该结构的传输原理,利用时域有限差分法仿真该结构的透射谱图及模场分布,并对器件中影响Fano线型的关键结构参数进行了优化。结果表明,该器件的品质因子可达22037.1,消光比为23.9 dB。采用折射率传感特性分析,得到该结构的灵敏度为354 nm·RIU−1,灵敏度的检测极限为2×10-4 RIU。因此,所提出的非对称法布里-珀罗腔槽型微环谐振器结构紧凑、性能优良,在传感应用方面优势较为明显。

关 键 词：micro-ring resonator(MRR) Fabry-Perot(FP)cavity Fano resonance refractive index sensing integrated optics silicon waveguide 

分 类 号：TN751.2[电子电信—电路与系统] TP212[自动化与计算机技术—检测技术与自动化装置]