US Patent 7899286 Optical coupling device

An optical coupling device for coupling an optical signal propagating in an optical fiber or space to an optical waveguide includes a lower cladding layer formed on a substrate, an optical waveguide formed on the lower cladding layer such that the tip of the optical waveguide points to an end portion of the lower cladding layer, and having a tapered distal end portion, and an upper cladding layer continuously formed on the lower cladding layer and on the distal end portion of the optical waveguide from the end portion of the lower cladding layer to the distal end portion of the optical waveguide, and having a refractive index higher than that of the lower cladding layer. The upper cladding layer draws light having entered the end portion of the lower cladding layer toward the upper cladding layer, and couples the light to the distal end portion of the optical waveguide.