Optical waveguide and method for fabricating the same

摘要

An optical waveguide comprises a cladding layer and a core segment buried in the cladding layer and serving as a waveguide. A combination of glass material constituting the core segment and another glass material constituting the cladding layer is selected so that an absolute value of a difference in a coefficient of thermal expansion between these materials (alpha1-alpha2) is within a range of 0 and 9x10^-7° C, where alpha1 denotes a coefficient of thermal expansion of the former material and alpha2 denotes that of the latter material.