温度与折射率同时测量的异质结构光纤SPR传感器对比研究

Comparative study of optical fiber SPR sensors with heterogeneous structure for simultaneous temperature and refractive index measurement

摘要:

为了探究不同异质芯结构光纤表面等离子体共振(surface plasmon resonance, SPR)传感器的温度和折射率(refractive index,RI) 传感性能,本文分别制备了基于多模(multimode fiber, MMF)-单模(single mode fiber, SMF)、MMF-无芯(nocore fiber, NCF)以及MMF-空芯(hollow core fiber, HCF)结构的反射式光纤SPR传感器。通过在光纤探头表面约一半区域涂覆温敏薄膜,实现了折射率与温度的同时测量,并比较分析了3种探头的温度和折射率传感特性。本文利用有限元法分析了传感器的温度和折射率双参量传感原理,并通过实验的方法分别对3种结构光纤探头的传感特性进行了分析和比较。实验结果表明,在3种光纤探头中,基于HCF的反射式SPR传感器的温度和折射率传感性能最优,在30—70 ℃的测温范围内,其温度灵敏度约为-1.604 5 nm/℃;在待测液折射率为1.331—1.37的范围内,其折射率灵敏度可达1 945.46 nm/RIU。

Abstract:

In order to investigate the temperature and refractive index (RI)sensing performances of optical fiber surface plasmon resonance (SPR) sensors with different heterogeneous core structures,reflective optical fiber SPR sensors based on multimode fiber (MMF)-single mode fiber (SMF),MMF-no core fiber (NCF),and MMF-hollow core fiber (HCF) structures were prepared respectively.By coating a temperature-sensitive film on approximately half of the surface of the optical fiber probe,the simultaneous measurements of the refractive index and temperature can be achieved.And the temperature and refractive index sensing characteristics of the three probes were compared and analyzed.In this paper,the finite element method was used to analyze the dual-parameter sensing principle of temperature and refractive index, and the sensing characteristics of the three structures of optical fiber probes were analyzed and compared by experimental methods.The experimental results show that among the three heterogeneous optical fiber probes,the HCF-based reflective SPR sensor has the best temperature and refractive index sensing performance.Within the temperature measurement range of 30—70 ℃,the temperature sensitivity is approximately -1.6045 nm/℃, while in the refractive index range of 1.3311.37its refractive index sensitivity reaches up to 1 945.46 nm/RIU.