US Patent 9162404 Radial optical coupler

An optical device includes an optical grating coupler and a plurality of optical waveguides coupled thereto. The optical grating coupler is formed along a planar surface of a substrate, and includes a pattern formed by ridges concentrically located on the surface about a center thereon. Each adjacent pair of ridges is separated by a groove. Each waveguide of the plurality of waveguides is oriented about radially with respect to the center, and has a first end that terminates near an outermost one of the ridges. The first ends are about uniformly spaced along the outermost one of the ridges.