A dual-core photonic crystal fiber sensor based on surface plasmon resonance is theoretically proposed for the high-sensitive detection of high refractive index liquid analytes. Dual-core construction can effectively enhance the coupling effect between the fiber-core mode and the surface plasmon polariton modes, leading to sharp loss peaks at the resonance wavelengths. As the refractive index of the targeted analyte varies, the resonance condition will change as well and cause a certain shift of loss peak. Numeric results show that this dual-core fiber sensor exhibits an average linear sensitivity 9538 nm/RIU and a maximum sensitivity is 11400 nm/RIU with a resolution 8.77 × 10⁻⁶ RIU. The detected range is broad and covers the high refractive index range from 1.45 to 1.58 with an average figure of merit 284.5 RIU⁻¹. The dependence of structure parameters and the thickness of coated-metal thin-film on sensing performance is performed systemically and suggests different responses. The proposed sensor is highly promising in detecting high refractive index liquid analytes in the fields of biological detection, environmental monitoring and chemical analysis.

理论上提出了一种基于表面等离子体共振的双核光子晶体光纤传感器，用于高折射率液体分析物的高灵敏度检测。双芯结构可以有效增强纤芯模式和表面等离子体激元模式之间的耦合效应，从而在谐振波长处产生尖锐的损耗峰值。随着目标分析物折射率的变化，共振条件也会发生变化，导致损耗峰发生一定的移动。数值结果表明，该双芯光纤传感器的平均线性灵敏度为9538 nm/RIU，最大灵敏度为11400 nm/RIU，分辨率为8.77 × 10 ^-6RIU。检测到的范围很宽，覆盖了从1.45到1.58的高折射率范围，平均品质因数为284.5 RIU ^-1。系统地研究了结构参数和涂层金属薄膜厚度对传感性能的依赖性，并提出了不同的响应。该传感器在生物检测、环境监测和化学分析领域检测高折射率液体分析物方面具有广阔的前景。