Silicon waveguides and ring resonators at 5.5 μm

We demonstrate low loss ridge waveguides and the first ring resonators for the mid-infrared, for wavelengths ranging from 5.4 to 5.6 μm. Structures were fabricated using electron-beam lithography on the silicon-on-sapphire material system. Waveguide losses of 4.0±0.7 dB/cm are achieved, as well as Q-values of 3.0 k.