Optical waveguide article with laminate structure and method for forming the same

An optical waveguide article comprising:

• a laminated glass sheet comprising a base layer and a surface layer fused to the base layer, the base layer formed from a first glass composition with a refractive index nbase, the surface layer formed from a second glass composition with a refractive index nsurface, nbase and nsurface satisfying the equation |nsurface−nbase|≥0.001;
• and
• a waveguide disposed within the surface layer,
• wherein the first glass composition of the base layer comprises a base coefficient of thermal expansion CTEbase, and the second glass composition of the surface layer comprises a surface coefficient of thermal expansion CTEsurface that is different than CTEbase such that the surface layer is under a compressive stress or a tensile stress.

A method of forming an optical waveguide article, the method comprising:

• applying a mask to an outer surface of a surface layer of a glass laminate structure comprising a base layer fused to the surface layer, the outer surface with the mask applied thereto comprising a covered portion and an uncovered portion;
• and
• selectively subjecting the uncovered portion of the outer surface to an ion exchange treatment to form a waveguide in the surface layer,
• wherein the base layer is formed from a first glass composition with a refractive index nbase, the surface layer is formed from a second glass composition with a refractive index nsurface, and nbase and nsurface satisfy the equation |nsurface−nbase|≥0.001.