LITHIUM NIOBATE SINGLE CRYSTAL THIN FILM SUBJECTED TO DOMAIN INVERSION TREATMENT

摘要

PURPOSE: To improve nonlinear optical characteristics by subjecting the surface of a lithium tantalate substrate to lattice matching, then to a domain inversion treatment in such a manner that polarization inverts in crystal axis direction at every synchronization. ;CONSTITUTION: The optically polished lithium tantalate substrate 1 is brought into contact with a melt consisting of Li₂O, Nb₂O₃, V₂O₅, Na₂O, and MgO and the lattice matched Na, Mg-contg. lithium niobate single crystal thin film 2 is grown thereon by an epitaxial growth method. Stripe patterns 3 are formed thereon by photolithography and Ti is deposited by vacuum evaporation over the entire surface thereof, by which a Ti thin film 4 is formed. The stripe patterns 3 are then removed and the substrate is subjected to a heating treatment to diffuse the Ti. The substrate is thereafter rapidly cooled, by which the lithium niobate single crystal thin film having the inverted domain layer 5 is obtd. A part of this crystal is then cut out and one line of pattern is drawn by photolithography method in the direction perpendicular to the Ti pattern. The Ti is deposited by vacuum evaporation and is subjected to ion beam etching, by which a ridge type waveguide 6 is formed.;COPYRIGHT: (C)1993,JPO&Japio