Abstract: A planar body of an oxide single crystal having a good crystallinity is grown stably to prevent cracks in the crystal when the planar body of the oxide single crystal is grown with a &mgr; pulling-down method. A raw material of the oxide single crystal is melted in a crucible 7. A seed crystal 15 is contacted to a melt 8. An oxide single crystal 31 is grown by pulling down the seed crystal 15 to draw the melt from an opening 13c of the crucible 7. A cooler is provided under the opening 13c of the crucible 7, which cool the oxide single crystal drawn from the opening of the crucible.

Abstract: An optical waveguide element is disclosed, which includes a three-dimensional optical waveguide of a bulky non-linear optical crystal, a substrate, and a joining layer made of an amorphous material through which the substrate is joined to the optical waveguide.

Abstract: A method of processing a substrate made of a ferroelectric single crystalline material, including the steps of forming a desired proton-exchanged layer in the substrate by proton-exchanging a portion of the substrate, and selectively removing the proton-exchanged layer to form a concave ditch structure in the ferroelectric single crystalline substrate, wherein the desired proton-exchange layer is formed by using an acid containing a lithium salt as a proton-exchanging source, the surface of the substrate from which the concave ditch structure is formed is an X-cut surface or a Z-cut surface, as a main surface, of the ferroelectric single crystalline material used as the substrate, and the concave ditch structure has a recessed portion with its depth equal to or larger than its half opening width.

Abstract: A method for producing a single-crystalline film made of a single crystal of lithium potassium niobate-lithium potassium tantalate solid solution or a single crystal of lithium potassium niobate, comprising the steps of preparing a target made of a material for the single-crystalline film, preparing a foundation made of a single crystal of lithium potassium niobate-lithium potassium tantalate solid solution or a single crystal of lithium potassium niobate, irradiating upon the target, thereby gasifying molecules constituting the target by dissociation and evaporation thereof, and epitaxially growing the single-crystalline film on the foundation.

Abstract: A planar body with a good crystallinity is grown continuously and stably when a planar body of an oxide single crystal is grown by a micro pulling-down method. A raw material of the oxide single crystal is melted in a crucible 7. A planar seed crystal 15 is contacted to a melt 18, and then the melt 18 is pulled down from an opening 13c of the crucible 7 by lowering the seed crystal. A planar body 14 is produced following the seed crystal 15. In this case, differences in lattice constants between each crystal axis of the seed crystal 15 and each corresponding crystal axis of the planar body 14 is controlled at 0.1% or less, respectively.

Abstract: An equipment is disclosed for producing a single crystal in each of plural containers by thermally treating a raw material for the single crystal each charged in each of the container, including heaters provided corresponding to each of the containers, an elevator to move each of the containers upward and downward relatively to the respective one of the heaters, and a connecting member to connect at least one of the container and the heater of each of plural sets of the containers and the heaters mechanically to the elevator, wherein each container is moved vertically relatively to the respective one of the heaters by driving the elevator and passed through an area of thermal treatment formed by the heater to continuously form a melt in the raw material inside the container, and the single crystal is continuously produced in the container by solidifying the melt.

Abstract: A planar body with a good crystallinity is grown continuously and stably when a planar body of an oxide single crystal is grown by a micro pulling-down method. A raw material of the oxide single crystal is melted in a crucible 7. A fibrous seed crystal 15 is contacted to a melt 18, and then the melt 18 is pulled down from an opening 13c of the crucible 7 by lowering the seed crystal. A shoulder portion 14A is produced following the seed crystal, and a planar body 14B is produced following the shoulder portion. In this case, differences in lattice constants between each crystal axis of the seed crystal and each corresponding crystal axis of the shoulder portion are controlled at 1% or less, respectively.

Abstract: A process is disclosed for producing an oxide single crystal, comprising the steps of: melting a raw material for a single crystal of an oxide inside a crucible, contacting a seed crystal with the resulting melt, growing the oxide single crystal by pulling-down the melt through an opening of the crucible in a given pulling-down axis, and fixedly holding the seed crystal and then reducing an angle of a given crystalline orientation of the seed crystal selected for growing the single crystal to the pulling-down axis.

Abstract: In a process for producing a raw material powder comprising lithium potassium niobate for growing a single crystal of lithium potassium niobate, starting raw materials comprising lithium carbonate powder, potassium carbonate powder and niobium pentoxide powder are mixed in a solvent, lithium carbonate powder and potassium carbonate powder are entirely dissolved into the solvent, lithium carbonate and potassium carbonate are deposited around niobium pentoxide powder by spray-drying the mixture to obtain granulated powder, and then the granulated powder is thermally treated to produce the raw material powder.

Abstract: A process for dicing a preform made of an oxide single crystal into cut pieces each having a given shape, includes the steps of removing molecules of the oxide single crystal through dissociation and evaporation with an optochemical reaction under irradiation of a laser beam upon the preform, thereby forming grooves on the preform, and then cleaving the preform along the groove.

Abstract: Equipment for producing a single crystal in each of a plurality containers by thermally treating raw material in each container, the equipement including heaters corresponding to each of the containers, an elevator to move each of the containers up or down relative to each respective heater, and a connecting member to connect at least one of the container and the heater, each of a plurality of sets of the containers and the heaters, mechanically to the elevator, wherein each container is moved vertically relative to the respective one of the heaters by driving the elevator. The container is passed through an area of thermal treatment formed by the heater so that a melt is continuously formed in the raw material inside the container. The single crystal is continuously produced in the container by solidifying the melt.

Abstract: An optical waveguide element includes a substrate showing electrooptical effects and having a pair of major planes opposed with each other, an optical waveguide formed on one major plane of the substrate, and an electrode for applying a modulation signal to an optical wave transmitted through the optical waveguide. In the optical waveguide element mentioned above, there are a thin thickness portion having a relatively thin thickness formed to a portion of said substrate at least positioned correspondingly to said electrode; and a buffer layer formed between said substrate and said electrode, wherein an impedance conformity with the modulation signal applied to said electrode is performed by controlling a thickness of said thin thickness portion.

Abstract: An optical waveguide device includes a substrate having a pair of opposed main planes, an optical waveguide formed on one of the opposed main planes, and an electrode portion, wherein a thickness of a portion of the substrate at at least a location where the electrode portion is formed is made smaller than at a remainder thereof.

Abstract: In producing an optical single crystal epitaxial film from a melt containing a transition metal on a single crystal substrate by a liquid phase epitaxial method, this process contains the steps of: annealing the film at a predetermined temperature in an ozonic atmosphere; and temperature-increasing and -decreasing to and from the predetermined temperature, wherein at least one of temperature-increasing and -decreasing steps, the film is exposed to a substantially ozone-free atmosphere.

Abstract: A second harmonic wave-generating element for generating a second harmonic wave from a fundamental wave, having an optical waveguide layer made of first epitaxial material having a fundamental composition of K3Li2−x(Nb1−YTaY)5+XO15+Z, an underclad part made of second epitaxial material having a fundamental composition of K3Li2−X+A(Nb1−Y−BTaY+B)5+X−AO15+Z, an overclad part made of third epitaxial material having a fundamental composition of K3Li2−X+C(Nb1−Y−DTaY+D)5+X−CO15+Z and formed on and contacting the optical waveguide layer, wherein X=0.006 to 0.5, Y=0.00 to 0.05, A=0.006 to 0.12, B=0.005 to 0.5, C=0.006 to 0.12, D=0.005 to 0.5, X−A≦0, X−C≧0, |A−C|≦0.006, and |B−D|≦0.005).

Abstract: A second harmonic wave-generation device for generating a second harmonic wave composed of an extraordinary ray from a fundamental wave composed of an ordinary ray, including a solid crystal of lithium potassium niobate-lithium potassium tantalate solid solution crystal or a single crystal made of lithium potassium niobate, wherein a mode field diameter of the fundamental wave inside the second harmonic wave-generation device is greater than that of the second harmonic wave.

Abstract: A process for growing a crystalline silicon plate, including the steps of arranging a planar growth member and a growth crucible in which a melt of silicon is placed and which is provided with a melt draw-out opening at a lower side thereof, while at least a tip portion of the growth member is located under the draw-out opening, drawing out the melt from the crucible through the draw-out opening, bringing the drawn out melt into contact with the tip portion of the growth member, and further pulling down the melt through the tip portion of the growth member.

Abstract: A process for producing an optical waveguide substrate including a ridge-shaped structural portion containing at least an optical waveguide, which process including the steps of forming an optical waveguide-forming layer on a substrate body to prepare a substrate workpiece, and forming said ridge-shaped structural portion at said substrate workpiece by grinding.

Abstract: A process for forming a microstructure at a surface of a substrate made of a ferroelectric single crystal, includes the steps of subjecting the substrate to a single-poling treatment, thereby one of an etching-easy surface and an etching-difficult surface being exposed to one of main faces of the substrate, while the other being exposed to the other main face, forming a domain-inverted region in at least one of the main faces of the substrate, and forming the microstructure at the substrate in the domain-inverted region of the substrate by selectively etching the substrate.

Abstract: A light modulator for modulating light upon application of a signal voltage, said light modulator including a substrate, an optical waveguide formed on a side of a front surface of the substrate, and first and secondary electrodes for applying the signal voltage to the light propagating through the optical waveguide, the first electrode being formed on a front surface side of the optical waveguide and including a main portion covering the front surface side of the optical waveguide and a first overhanging portion hanging over toward one side from the main portion.