High confinement micro-ring resonators in silicon-on-insulator

摘要

We demonstrate high confinement silicon devices including suspended micrometer-scale ring resonators with high Q's in a CMOS platform. Optical micro and nano scale resonant cavities have received much attention recently due to the enhanced light-matter interaction within these systems. Enhanced spontaneous emission (Purcell effect), strong coupling, two photon absorption, and Raman scattering are a few examples of phenomena which can be greatly enhanced in a high Q optical resonant cavity. The size of the cavities for on-chip applications can be greatly decreased in a high index contrast system due to increase in mode confinement. Recently, in order to benefit from the high index contrast between silicon and air, suspended disk resonators have been demonstrated. In these works the disk is suspended by a post beneath its center and the whispering gallery modes (WGM) propagate in the boundaries of the disks. Because of the low overlap between the optical mode and suspension mechanism, radiation losses are not inherent to these devices and therefore very high Q's can be achieved; however, the limitation of these disks lies in their multi-mode nature, and therefore low degree of confinement.