US Patent 10534136 High-efficiency fiber-to-waveguide coupler

An optical coupler comprises a waveguide structure including a first waveguide layer having proximal and distal ends, the first waveguide layer including a first pair of waveguides that extend from the proximal end along a first portion, wherein the first pair of waveguides each widen along a second portion such that the first pair of waveguides merge into a single waveguide. A second waveguide layer is separated from the first waveguide layer, with the second waveguide layer having proximal and distal ends, the second waveguide layer including a second pair of waveguides that extend from the proximal end of the second waveguide layer along a first portion of the second waveguide layer, wherein the second pair of waveguides each narrow along a second portion of the second waveguide layer to separate distal tips. The waveguide structure matches an integrated photonics mode to a fiber mode supported by an optical fiber.