Design and analysis of ring resonator with slot waveguide coupling into a slab ring construction for refractive index sensing applications

Abstract

AbstractWe proposed a theoretical study of silicon nitride ring resonator configuration for the application of refractive index sensing. In this paper, a slot waveguide has been used to couple the light into the slab ring structure. We have designed the slab ring and slot waveguides with silicon nitride (Si3N4) on a substrate made of silica (SiO2). Transverse electric (TE) mode has been used for the entire analysis at an operating wavelength of 1550 nm. The presented structure has been geometrically optimized to get the better transmission results. The design shows a resonance wavelength of 1538.74 nm when the cladding refractive index is equal to 1, which is placed at the top of the slab ring structure. We have also calculated the effect on the transmission curve for different waveguide parameters. For, the structure achieves a resonance wavelength around 1563.65 nm. The geometrically optimized structure achieved a Q‐factor of 750 and a sensitivity of 70 nm/RIU. In the proposed paper, the shift in the resonance of the transmission spectrum has been utilized to detect the Refractive Index (RI) changes on the surface of the ring. Therefore, the proposed structure can be used effectively in the applications of refractive index sensing.