Epitaxial growth of LiNbO3 optical-waveguide films by excimer laser ablation

摘要

The epitaxial growth of LiNbO$-3$/ films by the ArF excimer laser ablation is demonstrated to form electro-optic (EO) thin-film waveguides on sapphire and LiTaO$-3$/ c-plates. The x-ray diffraction spectra indicate that the resulting films are well oriented along the c axis when a Li-rich LiNbO$-3$/ ceramics is used as the target. The chemical composition of the film was successfully evaluated by measurement of the extraordinary index n$-e$/ on the basis of the guided-wave excitation with prism couplers. Stoichiometric films are grown on both sapphire and LiTaO$-3$/ c-plates by changing the content of excess Li$-2$/O in the target. The propagation loss of 6 dB/cm was attained in the thin-film waveguide on LiTaO$-3$/ c-plate. In addition, the EO effect of the film was roughly estimated by fabrication and characterization of a light deflector with an EO grating.