WAVE-GUIDING EPITAXIAL POTASSIUM LITHIUM-NIOBATE SINGLE-CRYSTAL FILMSDEPOSITED BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

Epitaxial potassium lithium niobate (KLN) single-crystal films were de posited on potassium lithium tantalate (KLT) singre-crystal substrates by low-pressure metalorganic chemical vapor deposition (MOCVD). Penta ethoxyniobium [Nb(OC2H5)(5)] and K and Li-dipivaloylmethane [K(DPM), L i(DPM)] were used as volatile metalorganic precursors. The crystallini ty of the films was investigated by X-ray diffraction measurements. Re ciprocal space mapping indicated that good epitaxial growth had been a chieved. The film surface was smooth enough to act as a waveguide. Sev eral guided modes were observed for both TE and TM waves by the prism coupler method. Refractive indices of the films for various wavelength s were determined and the phase matching property of the waveguide is discussed. The propagation loss, estimated by the cut-back method, was found to be 0.5 dB/cm at a wavelength of 633 nm.