Vertically emitting silicon disk resonators with periodic shape modulation

It is shown by direct numerical modeling, using the 3D FDTD method, that a disk resonator with a sinusoidal modulation of its boundary has not only a modified frequency spectrum, but also a greater proportion of its optical radiation is directed normal to its surface. Simulations are carried out for a set of disk resonators on a typical silicon-on-insulator structure with a 250-nm silicon core and a disk diameter of about 2.6 mu m with the 5% sinusoidal boundary perturbation. Depending on the optical wavelength, the far-field radiation pattern looks either like a quasihomogeneous optical beam or a torus, having a maximum or minimum intensity at its center, respectively. (C) 2017 Elsevier B.V. All rights reserved.