Simulation of Refractive Index Sensor Based on Microring Resonator

In the work reported here, we modeled a refractive index sensor based on microrings. This strategy has been applied with success in COMSOL Multiphysics. The proposed structure's free spectral range, sensitivity, and quality factor have received the majority of this study's attention. The resonant cavity refractive index sensor has been shown to function more effectively when the core layer width is close to micron size, the microring width is 1 $\mu \mathrm{m}$, and the radius is 34 $\mu \mathrm{m}$. Its quality factor is 224.67, its free spectral range is 16 nm, and its sensitivity is 160 nm/RIU, correspondingly.

I. Introduction

Optical waveguide sensors, as opposed to electrical signal-based sensors, detect based on optical signals, which can prevent electromagnetic field interference, offer greater stability, and greatly reduce environmental requirements [1]–[4]. Due to its numerous potential applications, researchers have long prized refractive index sensors. By building various optical structures, researchers have created various refractive index sensors. The advantages of grating-based fiber optic sensors [5], photonic crystal fiber (PCF) sensors [6], tapered fiber sensors [7], surface plasmon resonance sensor [8], and micro-ring resonators include simple structures, high integration, mature technology, low insertion loss, high quality factor, and low crosstalk. Based on a two-step heating procedure, Tong Limin created a nano-level fiber-optic waveguide in 2003 [9]. It is extremely ideal for on-chip integration with other optoelectronic devices since the microring resonator's resonance does not require grating or cavity surface feedback, and the application is quite versatile [10]. A bigger free spectral region FSR can also be generated by linking microrings of various radii together in sequence, which is advantageous for boosting the number of channels. Moreover, a highly flat spectral response can be attained by cascading a number of microrings. Several researchers have suggested the building of intricate microring arrays using the microrings' cascade features, generating fresh perspectives on optoelectronic integration research. This work explores the microring resonator in the micrometer range using COMSOL simulation software, taking into account the real application cost and sensor stability.