Tunable silicon microring resonator with wide free spectral range

The authors present a silicon-on-insulator single ring resonator with a free spectral range equal to $47\mathrm{nm}$ , which is the widest known value for this type of resonators. The ring radius is $2\mu \mathrm{m}$ and is the smallest ring resonator ever reported, achieving experimentally such a wide spectral range. For this ring resonator, the authors demonstrate the quality factor to be equal to $6730\pm 60$ . They thermally tune the resonant wavelength with $0.11\mathrm{nm}∕°\mathrm{C}$ , thus showing the ring resonator as an attractive component for on-chip ultracompact photonic add/drop filters and switches.