The optical waveguide characteristics of highly orientated sol–gel derived polycrystalline ferroelectric PZT thin films

PZT ferroelectric thin films were deposited on various substrates by the sol–gel method. The close relationship between structure and refractive indexes was studied. The optical propagation losses of thin films were measured using the prism-waveguide coupling technique. The optical propagation loss of the films derived on SiO2/Si (111) substrates is increased by increasing the heat treatment temperature. The optical propagation loss is not significantly increased at increased coating thickness. Epitaxial PZT thin films on SrTiO3(l00) single crystal substrate had a single (001) orientation and showed optical propagation loss as small as 14.2 dB/cm at 632 nm.