Wang Qi, Li Chunyue, Zhao Chengwu, Li Weizheng
College of Information Science and Engineering, Northeastern University, Shenyang 110819, China.
State Key Laboratory of Synthetical Automation for Process Industries, Northeastern University, Shenyang 110819, China.
Sensors (Basel). 2016 Jun 1;16(6):801. doi: 10.3390/s16060801.
A cascaded symmetrical dual-taper Mach-Zehnder interferometer structure based on guided-mode and leaky-mode interference is proposed in this paper. Firstly, the interference spectrum characteristics of interferometer has been analyzed by the Finite Difference-Beam Propagation Method (FD-BPM). When the diameter of taper waist is 20 μm-30 μm, dual-taper length is 1 mm and taper distance is 4 cm-6 cm, the spectral contrast is higher, which is suitable for sensing. Secondly, experimental research on refractive index sensitivity is carried out. A refractive index sensitivity of 62.78 nm/RIU (refractive index unit) can achieved in the RI range of 1.3333-1.3792 (0%~25% NaCl solution), when the sensor structure parameters meet the following conditions: diameter of taper waist is 24 μm, dual-taper length is 837 μm and taper distance is 5.5 cm. The spectrum contrast is 0.8 and measurement resolution is 1.6 × 10(-5) RIU. The simulation analysis is highly consistent with experimental results. Research shows that the sensor has promising application in low RI fields where high-precision measurement is required due to its high sensitivity and stability.
本文提出了一种基于导模和泄漏模干涉的级联对称双锥马赫-曾德尔干涉仪结构。首先，采用有限差分光束传播法（FD-BPM）分析了干涉仪的干涉光谱特性。当锥腰直径为20μm - 30μm、双锥长度为1mm且锥间距为4cm - 6cm时，光谱对比度较高，适用于传感。其次，开展了折射率灵敏度的实验研究。当传感器结构参数满足以下条件：锥腰直径为24μm、双锥长度为837μm且锥间距为5.5cm时，在1.3333 - 1.3792（0%~25% NaCl溶液）的折射率范围内可实现62.78 nm/RIU（折射率单位）的折射率灵敏度。光谱对比度为0.8，测量分辨率为1.6×10(-5) RIU。模拟分析与实验结果高度一致。研究表明，该传感器因其高灵敏度和稳定性，在需要高精度测量的低折射率领域具有广阔的应用前景。
