A simple design of photonic crystal fiber (PCF)–based surface plasmon resonance (SPR) sensor is proposed and investigated numerically for the detection of large analyte refractive index (RI) range. An open U-shaped analyte channel is introduced at the top side and along the length of the fiber to detect unknown analytes. The U-shaped channel helps to generate large amount of surface plasmon resonance on the plasmonic metal layer (gold) by reducing the distance between core and sensing medium. The optical properties and sensitivity of the sensor are analyzed by using the finite element method. The simulation results suggest that the sensor can detect analyte refractive index ranging from 1.33 to 1.44 with maximum wavelength sensitivity of 66,000 nm/RIU and resolution of 1.52 × 10⁻⁰⁶ RIU. It also exhibits the maximum amplitude sensitivity of 2,940 RIU⁻¹ with sensor resolution of 3.40 × 10⁻⁰⁵ RIU. Furthermore, a good figure of merit (FOM) of 1734 RIU⁻¹ and maximum limit of detection (LOD) of 2.29 × 10⁻¹¹ RIU²/nm are achieved by the proposed sensor. Additionally, the fabrication tolerance in terms of pitch, air-hole diameter and channel size is investigated. Finally, we can anticipate that the sensor will be a suitable candidate to detect unknown analytes such as biological or biochemical samples for its high sensitivity with wide sensing range.

提出了一种基于光子晶体光纤 (PCF) 的表面等离子体共振 (SPR) 传感器的简单设计，并进行了数值研究，用于检测大分析物折射率 (RI) 范围。一个开放的 U 形分析物通道被引入光纤的顶部和长度，以检测未知的分析物。U 形通道通过减少核心和传感介质之间的距离，有助于在等离子体金属层（金）上产生大量的表面等离子体共振。采用有限元方法分析了传感器的光学特性和灵敏度。仿真结果表明，该传感器可以检测1.33~1.44的分析物折射率，最大波长灵敏度为66,000 nm/RIU，分辨率为1.52 × 10 ^-06里乌。它还表现出 2,940 RIU ^-1的最大幅度灵敏度，传感器分辨率为 3.40 × 10 ^-05 RIU。此外，所提出的传感器实现了1734 RIU ^-1的良好品质因数（FOM）和2.29 × 10 ^-11 RIU ² /nm 的最大检测限（LOD）。此外，研究了节距、气孔直径和通道尺寸方面的制造公差。最后，我们可以预期该传感器将成为检测未知分析物（例如生物或生化样品）的合适候选者，因为它具有高灵敏度和宽传感范围。