Grating lens and focusing grating coupler

A diffracting grating lens comprising a body having a surface on which a plurality of grating elements are formed, each grating element comprising one period, along a width direction of said grating element, of a portion having a higher refractive index and a portion having a lower refractive index said grating lens having variable period sizes, the plurality of grating elements varying in depth along a direction of a line included in a plane parallel with said surface of said body to vary diffraction efficiency with the variation in the dept of said plurality of grating elements along said direction of said line.

A focusing grating coupler comprising a substrate having a surface formed with an optical waveguide thereon and a grating formed on said optical waveguide and comprising a plurality of grating elements, each grating element comprising one period of a ridge and a groove, said plurality of grating elements varying in depth along a direction of a line included in a plane parallel with the substrate surface to vary diffraction efficiency with the variation in depth of said plurality of grating elements along said direction of said line.