High bandwidth SOI photonic wire ring resonators using MMI couplers

A ring resonator in SOI photonic wire waveguides is demonstrated using a compact MMI coupler with 3 mu m x 9 mu m footprint as the coupling element. We achieved high bandwidth of 0.25 nm, and a quality factor Q of similar to 6000 for rings with a radius of 50 mu m. Unlike directional coupler based rings, these resonators have a wavelength independent Q and extinction ratio over more than 30 nm wavelength range, and there is no loss penalty for increasing the bandwidth. Compared to their directional coupler based counterparts, these resonators also have less demanding fabrication requirements and are compatible with high speed signal processing and optical delay lines. (c) 2007 Optical Society of America.