Patent ID: 6996324

Claim:
An optical waveguide comprising: a cladding constituting a second glass material; and a core segment constituting a first glass material buried in said cladding; wherein: said first glass material comprises borosilicate crown class comprising silicon dioxide, boric oxide, an alkaline metal oxide of the formula R 2 O in which R is an alkali metal, and a diatomic metal oxide of the formula LO in which L is a diatomic metal; said second glass material comprises fluorine crown glass comprising silicon dioxide, boric oxide, an alkaline metal oxide of the formula R 2 O in which R is an alkali metal, and a fluorine containing compound; said first glass material, having a coefficient of thermal expansion α1, and said second glass material, having a coefficient of thermal expansion, α2, are combined so that an absolute value of difference in coefficient of thermal expansion between said glass materials, (α1-α2), is within a range of 0 and 9×10 −7 /° C., and where α1 and At1 respectively denote the coefficient of thermal expansion and the yield point of said first glass material, and α2 and At2 respectively denote the coefficient of thermal expansion and the yield point of said second glass material.