A dual-polarized photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) was proposed for measuring the refractive indexes (RIs) of liquids. A gold film and a liquid analyte were successively wrapped around the outer surface of the PCF to stimulate the external SPR effect, which greatly reduced the manufacturing difficulties, compared to depositing the gold film and filling the inner air holes of the PCF with liquid analyte. The performance of the proposed PCF sensor was numerically investigated using the finite-element method. The results show that the proposed PCF sensor can realize dual-polarized detection in the RI range of 1.36–1.42. The x and y polarization (X-P and Y-P) core modes were coupled to the X-P second-order and Y-P first-order surface-plasmon polariton modes, respectively. As the the RI of the analyte increased, the wavelength sensitivity increased and, as a result, maximum values of 15 900 nm RIU⁻¹ for X-P and 16 900 nm RIU⁻¹ for Y-P were achieved. Correspondingly, we obtained a maximum amplitude sensitivity of 2026.05 RIU⁻¹ for X-P and 2102.65 RIU⁻¹ for Y-P. In addition, the fabrication tolerance of the proposed PCF was increased to 0.4 μm, which made the proposed PCF a favorable candidate for the detection of liquids.

提出了一种基于表面等离子体共振 (SPR) 的双偏振光子晶体光纤 (PCF) 传感器来测量液体的折射率 (RI)。金膜和液体分析物依次包裹在PCF的外表面以激发外部SPR效应，与沉积金膜并用液体分析物填充PCF的内部气孔相比，大大降低了制造难度。使用有限元方法对所提出的 PCF 传感器的性能进行了数值研究。结果表明，所提出的PCF传感器可以在1.36-1.42的RI范围内实现双偏振检测。在X和Y ^极化（XP 和 YP）核心模式分别耦合到 XP 二阶和 YP 一阶表面等离子体极化子模式。作为分析物的所述RI增加，波长灵敏度增加，并且，其结果是，15 900纳米RIU的最大值^-1为XP和16 900nm的RIU ^-1分别实现为YP。相应地，我们获得了XP 的 2026.05 RIU ^-1和 YP的 2102.65 RIU ^-1的最大幅度灵敏度。此外，所提出的PCF的制造公差增大到0.4 μ米，这使得所提出的PCF的有利候选者用于检测液体。