Dual-Channel Surface Plasmon Resonance–Based Photonic Crystal Fiber Sensor with Metal-Ta2O5 Coating at Near-infrared Wavelength

This work proposes a novel multi-channel photonic crystal fiber (PCF) based on surface plasmon resonance (SPR) technique where Au-Ta2O5 layer and Ag-Ta2O5 layer are selected as plasmonic materials. Dual-analyte simultaneous measurement can be well implemented by individually monitoring the SPR intensities of the x-polarized and y-polarized modes in the near-infrared region. Using a full-vectorial finite element method (FV-FEM) and COMSOL software, we have theoretically elucidated the effects of related parameters comprising coating thickness and pitch parameter on the sensing response. The optimized results show that the proposed sensor has attended to average wavelength sensitivities of 11,466 nm/RIU and 6833 nm/RIU, with maximum amplitude sensitivities of − 940.1/RIU and − 1008/RIU for channel 1 and channel 2, respectively. A ± 2% structural error of air holes has been taken into consideration and shows little impact on the wavelength sensitivities. Moreover, our sensing response is of excellent linear characters with R2 of the polynomial lines up to 0.9983 and 0.9993.