Optimization of a dual-slot waveguide for a refractive index biosensor

Abstract

The present article illustrates the modeling and optimization of a dual-slot waveguide for the application of a refractive index biosensor. The nanometer scale waveguide structure uses the silicon-on-insulator platform for the consideration of higher sensitivity and compactness of a resonator biosensor. The modal analysis is performed using the finite difference method based on full vector eigenmode calculation. The maximum field penetration in the lower index region is found for the quasi-TE mode. The sensitivity is maximized through the optimization of the waveguide dimension by relating effective refractive index with the dispersion of a waveguide. The biosensor showed the maximum calculated sensitivity of 461.327 nm/RIU and a limit-of-detection of 2.601 × 10–6 RIU (where RIU denotes refractive index unit).