The sol-gel process was used to fabricate epitaxial thin films of crys
talline ferroelectric oxides, including KNbO3 film on single crystal s
ubstrates of MgO and SrTiO3, LiNbO3 film on LiTaO3 and alternatively m
ultilayer nX(SrTiO3/PbTiO3) Films on SrTiO3. Fabrication of these epit
axial thin films will be described. The structure of these films has b
een studied with X-ray, electron diffraction, and high resolution elec
tron microscopy. Second harmonic generation of 1064 nm incident light
was demonstrated in KNbO3 waveguides. Transient photorefractive gratin
gs in Fe-doped KNbO3 were studied by a two-beam coupling technique at
various writing intensity and wavelength.