Design and analysis of graphene-Au-coated biosensor based on dual-core photonic crystal fiber

This paper numerically characterizes a photonic crystal fiber (PCF) surface plasmon resonance (SPR) biosensor using finite element method (FEM)-based COMSOL Multiphysics simulation software. The modal refractive index (RI) of the core-guided mode is successfully controlled by modifying the PCF's air hole diameters, and the sensor is seen to have significant birefringence. Analyte channels are employed in the center hole, surrounded by graphene-Au bimetallic layers to reduce surrounding interference. The features of graphene allow it to minimize oxidation and improve molecular absorption. By analysis of wavelength and amplitude characteristics, the performance of the developed sensor is examined; when the analyte refractive index is 1.34, the sensor's wavelength sensitivity is 15,000 nm/RIU for x-polarization and 10,000 nm/RIU for y-polarization. The amplitude sensitivity of x-polarization is 88 RIU-1, while that of y-polarization is 425 RIU-1. Both polarizations have a resolution of 1 x 10(-3) RIU. Thus, the proposed PCF can be used as the basis for building a real-time, higher-sensitivity, and fast-responding sensor.