Optimized passive design space exploration of silicon microring resonators

In this work, we analyze passive parameters for a band of 1500 to 1600 nm in microring resonators (MRRs). Such analysis can be vital for estimating an appropriate parameter design exploration with potential applications on Wavelength Division Multiplexing (WDM) solutions. Using a coupled mode theory-based method, we found optimal design spaces for MRRs with radii from 5 to 10 µm and bus-ring gap from 0.12 to 0.21 µm. For All-Pass MRRs, we found an optimal design space where the transmittances in the resonant frequencies are down to 8% in the Through port, while for the Add-Drop MRRs, we found an optimal design space where for transmittances in the Drop port are from 0.77 to 1. We also found optimal design spaces for Q-factors between 2000 and 3800. To find the optimal ring/radius and bus-ring gap values inside the design spaces, we use the particle swarm optimization technique. The data obtained with the exhibited work also shows a modal analysis for the supermodes formed by the cross-section of the bus-ring interface and the impact of UV-lithography common fabrication errors, even due to wafer die positioning. With the latter, our work provides a comprehensive design space exploration and helps designers to know the effect that typical structural fabrication errors will have on the passive resonance.