An optical waveguide, a fabrication method therefor and an optical waveguide
device
are disclosed wherein a sink of a core layer (waveguide core) can be suppressed
while formation of cracks and air bubbles is suppressed. The optical waveguide
comprises a substrate, and a lower clad layer, a core layer and an upper clad layer
formed on the substrate such that the core layer is buried within the upper and
lower clad layers. The lower clad layer is formed from a silica glass-type material,
which is formed using a trialkylsilyl-type compound as an organic source, such
that the melting temperature thereof is higher by a predetermined temperature or
more than that of the upper clad layer.
