Optimization of Integrated Optical Microring Resonators for Enhanced Sensing Applications

This research introduces an innovative integrated optical microring resonator (IOMR) tailored for a variety of sensing applications, with a particular emphasis on force sensing. And the study utilizes the Finite-Difference-TimeDomain (FDTD) method to fine-tune essential parameters, including the widths of the microring and bus waveguides, as well as the coupling gap. The resulting optimized IOMR exhibits an impressive quality factor (Q-factor) of $\mathbf{1 8, 2 4 1}$ and free measurement tool. The microring, characterized by a radius of $5 \mu \mathrm{~m}$ and a thickness of 220 nm, is integrated into a microcantilever beam (MCB) to amplify its responsiveness to external forces. The sensor functions based on the photo-elastic effect, where variations in the effective refractive index occur in response to applied forces, resulting in a measurable shift in the resonant wavelength. The sensitivity of the force sensor is quantified at 5 pm per $1 \mu \mathrm{~N}$, with a detection range extending from 0 to $1 \mu \mathrm{~N}$. This study underscores the potential applications of optimized IOMRs in various fields, including pressure, acceleration, and biosensing.