Optical waveguide and method for fabricating the same

Abstract

An optical waveguide comprising claddingand core segmentburied in claddingand serving as a waveguide, wherein a combination of glass material constituting the core segmentand another glass material constituting the claddingis so selected that an absolute value of difference in coefficient of thermal expansion between these materials (α1-α2) is within a range of 0 and 9×10° C., where α1 denotes a coefficient of thermal expansion of the former material and α2 denotes that of the latter material. Since this makes possible to bond directly the glass materials having different refraction factors and different coefficients of thermal expansion, and to produce the optical waveguide at even a lower temperature as compared to the prior art method as an upper cladding layer is formed with the sputtering method, it realizes reduction in number of processes and time of manufacture, thereby providing the optical waveguide of low transmission loss at low cost, as well as a method of manufacturing the same.