Guided-Mode-Leaky-Mode-Guided-Mode Fiber Interferometer and Its High Sensitivity Refractive Index Sensing Technology.
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.
College of Information Science and Engineering, Northeastern University, Shenyang 110819, China. wangqi@ise.neu.edu.cn.|State Key Laboratory of Synthetical Automation for Process Industries, Northeastern University, Shenyang 110819, China. wangqi@ise.neu.edu.cn.
Qi
Q
Wang
College of Information Science and Engineering, Northeastern University, Shenyang 110819, China. 20123553@stu.neu.edu.cn.
Chunyue
C
Li
College of Information Science and Engineering, Northeastern University, Shenyang 110819, China. 20123645@stu.neu.edu.cn.
Chengwu
C
Zhao
College of Information Science and Engineering, Northeastern University, Shenyang 110819, China. 20133541@stu.neu.edu.cn.
Weizheng
W
Li
Mach-Zehnder interferometer; Micro-Nano fiber; high sensitivity; optical fiber sensor; refractive index measurement