Novel Ring Resonator Combining Strong Field Confinement With High Optical Quality Factor

Slot waveguide ring resonators appear promising candidates for several applications in silicon photonics. Strong field confinement, high device tunability, and low power consumption are beneficial properties compared with strip waveguides. Slot waveguide ring resonators suffer, however, from rather low optical quality factors due to optical losses. This letter proposes and experimentally demonstrates a novel concept based on a partially slotted ring and a strip-to-slot mode converter. An exceptional high quality factor of
${\sim }10^{5}$
has been measured.