Design of Microrings with Complex Waveguide Cross-Sections to Reduce Non-linear Effects of Silicon

This study presents a model for designing silicon and polysilicon (poly-Si) micro-ring resonators (MRRs) within the semiconductor-insulator-semiconductor capacitor platform (SISCAP). It employs generic waveguide cross-sections, including complex rib structures, to address nonlinear effects and self-heating. We highlight the crucial role of free carrier diffusion in rib waveguides and Shockley-Read-Hall recombination in mitigating nonlinearities within the ring resonator. In particular, we introduce a novel method for 2D simulations of MRRs, incorporating self-consistent generation of free carriers via TPA, their transport, non-radiative recombination, heat generation, and dissipation. These factors alter the MRR transmission coefficient, significantly diminishing the quality factor (Q) as injected power increases. The amount of input power injected into the ring is limited when high Q values ( \(1.3\cdot {10}^{5}\) ) are considered. Our objective is to propose new designs capable of increasing the input power by an order of magnitude while limiting the Q degradation to less than 10%, which is crucial for enhancing MRR performance in various silicon photonics applications.