Numerical Analysis of a Highly Sensitive SOI MRR Refractive Index Sensor with Performance Enhancement using Graphene and Gold

Abstract: This study proposes a simulation-based design for a Silicon-On-Insulator (SOI) ring resonator with a Figure of Merit (FOM) of 56.15 and a high sensitivity of up to 730 nm/RIU. The Finite-Difference Time-Domain (FDTD) technique was used to assess and evaluate the design quantitatively. Our design demonstrates higher sensitivity compared to many recent studies conducted on SOI-based sensors. The device structure follows a conventional ring resonator arrangement with a single waveguide, incorporating a 2D graphene layer on top of the SiO2 wafer and a gold nano-disc positioned at the center of the ring. Our findings highlight the device's susceptibility to refractive index variations, making it a desirable choice for various sensing applications. We have investigated the sensor's capabilities for sensing different concentrations of milkmilk. Graphene and gold materials enhance the device's response to light and provide comparatively higher sensitivity. The suggested design can serve as a blueprint for device fabrication, considering the practicality of implementing an SOI-based device using standard techniques for silicon processing.