Athermalization of a silica-based waveguide with a UV-induced Bragg grating on a crystallized glass substrate

To realize athermal glass films, formation of Ge-B-SiO2 and F-B-SiO2 films by plasma-enhanced chemical vapor deposition (PECVD) was examined-on several substrates with various thermal expansion coefficients. Waveguide Bragg gratings were fabricated by irradiation with a KrF excimer laser light through a phase mask. A temperature dependence of the Bragg wavelength as low as 4 pm/degreesC was obtained in a 6GeO(2)-13B(2)O(3)-81SiO(2) (mol%) core and 13B(2)O(3)-87SiO(2) (mol %) cladding waveguide or in a 13B(2)O(3)-87SiO(2) (mol %) core, 6GeO(2)-13B(2)O(3)-81SiO(2) (mol%) grating layer and 6F(2)-10B(2) O-3-84SiO(2) (mol%) cladding waveguide on crystallized glass substrates with a thermal expansion. coefficient of -2.0 x 10(-6)/degreesC. Such temperature sensitivity is one third of conventional waveguide Bragg grating devices.