US Patent 11953725 Grating coupler and method of manufacturing the same

A device includes a dielectric layer, a plurality of grating structures, and a dielectric material between the plurality of grating structures and on top of the plurality of grating structures. The grating structures are arranged on the dielectric layer and separated from each other, the plurality of grating structures each having a bottom portion and top portion, the top portion having a first width and the bottom portion having a second width, the second width being larger than the first width.