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 47nm, which is the widest known value for this type of resonators. The ring radius is 2μm 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±60. They thermally tune the resonant wavelength with 0.11nm∕°C, thus showing the ring resonator as an attractive component for on-chip ultracompact photonic add/drop filters and switches.