Ultra-high Q multimode waveguide ring resonators for microwave photonics signal processing

We propose and experimentally demonstrate a novel type of silicon race-track resonators realized in standard SOI process with quality factors above 1.3 million. The proposed solution uses multi-mode waveguides (MMWG) and couplers in order to dramatically reduce the waveguide loss in the coupler and in the ring cavity, and therefore achieve high Q factors compared to previous implementations of resonators in SOI without sacrificing the free-spectral range. The resonator has been employed to demonstrate an RF notch filter with a 150 MHz stopband and 8 GHz tuning range.