长周期光纤光栅高灵敏度折射率传感研究

Research on high sensitivity refractive index sensing of long period fiber grating

摘要:

基于长周期光纤光栅(LPFG)对环境折射率变化敏感的特性，本文提出了一种基于强度检测的LPFG高灵敏度折射率传感方案。理论分析和仿真验证了LPFG谐振峰强度对外界折射率变化敏感的特性；同时，仿真了应变对LPFG谐振峰强度的影响，通过对比0和200με下LPFG谐振峰强度随环境折射率的变化，验证了增加应变可以实现折射率传感灵敏度的提升。经过实验验证，在1.4498-1.4558的折射率范围内，LPFG折射率传感初始灵敏度为1985dB/RIU；通过增加应变，在1.4498-1.4568的折射率变化范围内，LPFG折射率传感灵敏度提升到3182.9dB/RIU，可以实现高灵敏度的折射率传感。该传感方案具有结构简单，折射率传感灵敏度高等特点，在生物、化学及环境参数检测等领域具有潜在的应用价值。

Abstract:

Based on the sensitivity of long-period fiber grating(LPFG) to the change of environmental refractive index, a high-sensitivity refractive index sensor of LPFG based on intensity detection is proposed. In this paper, the sensitivity of LPFG resonance peak intensity to external refractive index changes is verified by theoretical analysis and simulation. At the same time, the effect of strain on LPFG resonance peak intensity was simulated. By comparing the variation of LPFG resonance peak intensity with the environmental refractive index at 0 and 200με, it was verified that increasing strain can improve the sensitivity of refractive index sensor. The experimental results show that the initial refractive index sensitivity of LPFG is 1985dB/RIU in the refractive index range of 1.4498-1.4558. By increasing the strain, the LPFG refractive index sensor sensitivity is increased to 3182.9dB/RIU in the refractive index variation range of 1.4498-1.4568, which can achieve high sensitivity refractive index sensing. The sensor has the advantages of simple structure, high sensitivity, and has potential application value in the fields of biological, chemical and environmental parameter detection.