Dynamically Tunable Q-Factor in an Integrated Optical Double Ring Resonator with Shared Bus Waveguide

We present an integrated optical structure consisting of two ring resonators sharing a single optical bus waveguide. This configuration enables precise control over the quality factor (Q‑factor) of the primary ring resonator by adjusting the refractive index of an uncoupled auxiliary ring. Using the Finite Difference Time Domain (FDTD) simulations, we validate this design concept and demonstrate that the Q-factor can be dynamically and continuously tuned by over 200%, shifting from an initial value of approximately 490 to nearly 1000 via localized thermal tuning. This post-fabrication tuning technique offers an effective, dynamic approach to mitigating fabrication tolerance variations.