A halogenated polyamide acid composition containing a halogenated
polyamide acid, a metal oxide precursor, a catalyst of reaction of
generating a metal oxide from the precursor, and/or a coupling agent
having a reactive group. A halogenated polyimide film is obtained by, for
example, carrying out the heat treatment of the halogenated polyamide
acid composition. The halogenated polyimide film has a refractive index
at wavelength of, for example, 1,550 nm of 1.520 or lower. Further, an
optical waveguide uses the halogenated polyimide film as at least one of
a core layer and a clad layer, and a relative refractive index difference
between the core layer and the clad layer of the optical waveguide is,
for example, 0.6 or greater. An optical waveguide device contains such an
optical waveguide.