Optical waveguide elements, optical wavelength conversion elements, and process for producing optical waveguide elements

An optical waveguide element comprising a three-dimensional optical waveguide comprising a bulky non-linear ferroelectric optical crystal, and an underclad for the optical waveguide, wherein the three-dimensional waveguide is formed in such a thickness, by mechanically working the non-linear optical crystal, to permit light to be confined, and the underclad comprises an amorphous material.

A process for producing an optical waveguide element, comprising the steps of joining an optical waveguide-forming material comprising a bulky non-linear ferroelectric optical crystal to a separate substrate via a joining layer of an amorphous material, and forming a three-dimensional optical waveguide by working the optical waveguide-forming material, wherein the joining layer has a refractive index smaller than that of the non-linear optical crystal and extends across the entire surface of the substrate.

A process for producing an optical waveguide element, comprising the steps of joining an optical waveguide-forming material comprising a bulky non-linear ferroelectric optical crystal to a separate substrate via a joining layer of an amorphous material, and forming a three-dimensional optical waveguide by working the optical waveguide-forming material, wherein the substrate has a refractive index smaller than that of the non-linear optical crystal, and the joining layer extends across the entire surface of the substrate.

An optical wavelength conversion element comprising a three-dimensional optical waveguide comprising a slab-shaped non-linear ferroelectric optical crystal, and clad layers of an amorphous material on upper and lower surfaces of the optical waveguide and extending over the upper and side surfaces of the optical waveguide.