  Construction of a large-scale cryogenic gravitational-wave telescope KAGRA
has been completed and the four sapphire test masses have been installed in
cryostat vacuum chambers. It recently turned out that a sapphire substrate used
for one of the input test masses shows a characteristic strcuture in its
transmission map due to non-uniformity of the crystal. We performed an
interferometer simulation to see the influence of the non-uniformity using
measured transmission/reflection maps.
