Design and characterization study of dual D-shaped no-core fiber based SPR sensor for refractive index and temperature measurement

作     者：Liu Yinggang Li Rui Li Fei Xu Xinyi Zhou Rui 

作者机构：Shaanxi Engineering Research Center of Oil and Gas Resource Optical Fiber Detection & Shaanxi Key Laboratory of Measurement and Control Technology for Oil and Gas wells， Xi'an Shiyou University 

出 版 物：《Optoelectronics Letters》 (光电子快报(英文))

年 卷 期：2025年

学科分类：080202[工学-机械电子工程] 08[工学] 0802[工学-机械工程] 

基　　金：supported by the Scientific Research Project of Shaanxi Provincial Department of Education (20JS122) the Postgraduate Innovation and Practice Ability Development Fund of Xi’an Shiyou University (YCS23213189) 

摘      要：To address the issue of temperature cross-sensitivity in refractive index （RI） measurement， a fiber-optic Surface Plasmon Resonance （SPR） sensor based on dual D-shaped no-core fiber （NCF） is proposed and designed. The sensor mainly consists of D-shaped NCF， Ag/Fe2O3composite film， and polydimethylsiloxane （PDMS）， where the silver and Fe2O3are successively coated on both D-shaped surfaces of NCF to generate SPR and enhance the oxidation resistance. The layer of PDMS coated on one D-shaped surface acts as a tunable ambient medium sensing the temperature variation and affecting the transmission spectrum of the sensor. Since the surface plasmon waves are excited in the two D-shaped surfaces with different films， the two RI and temperature-dependent spectral resonance peaks with different wavelengths will be produced. Research results demonstrate that the two peaks’ wavelengths have different responses to the variations of ambient RI and temperature. In the refractive index range of 1.36-1.376 and temperature range of 10-100 °C， the RI and temperature sensitivities reach to 5000 nm/RIU and -0.546 nm/°C， respectively. With the sensitivity coefficient matrix， simultaneous measurement of refractive index and temperature can be realized， and the corresponding accuracy is superior to 0.4×10-5RIU and 0.037°C.