Abstract: An optical waveguide device has a substrate composed of a nonlinear optical material and a periodically domain-inverted structure having the same composition as the nonlinear optical material, where the domain-inverted structure has a refractive index distribution relying on the domain-inverted structure.

Abstract: It is provided system and method of oscillating blue laser beam having a relatively high conversion efficiency and whose output power of the blue laser beam can be improved. Light emitted from a broad area semiconductor laser device 2 of Fabry-Perot type is irradiated into a slab optical waveguide 8 made of a non-linear optical crystal as a fundamental wave “A”. Blue laser beam “B” is emitted from the slab optical waveguide 8.

Abstract: An optical waveguide device includes a waveguide layer that converts a wavelength of incident light and emits converted light. In the waveguide layer, a ridge waveguide and slab waveguides are provided, the slab waveguides being formed on both sides of the ridge waveguide with recess portions intervening therebetween. The waveguide layer satisfies a multi-mode condition for the incident light, and light propagating through the ridge waveguide is in a single mode.

Abstract: Major surface of a substrate having an optical waveguide and a modulation electrode is pasted to a base substrate through a thermosetting resin, and then the rear surface of the substrate is machined thus making thin the entirety. Subsequently, the rear surface of the substrate thus rendered thin is subjected to machining or laser machining to form a thin part, which is further subjected to machining or laser machining to form a first thin part at a part, including the optical waveguide, of the thin part and a second thin part thinner than the first thin part contiguously thereto. Thereafter, the rear surface of the substrate is pasted to the major surface of a supporting substrate through a thermosetting resin and the base substrate is stripped thus obtaining an optical modulator.

Abstract: An object of the present invention is to provide a practical device for generating blue laser beam having a wavelength of 457 nm. The present invention provides a device for generating blue laser beam. The device has a solid-state laser oscillator 3 composed of Nd-doped YVO4 crystal and having a length of not smaller than 0.1 mm and not larger than 1.0 mm, a reflecting means 6A, 6B provided in the oscillator 3, an illuminating means 1 for illuminating pump light beam to the oscillator 3, and a waveguide-type device 5 for generating harmonic wave. The oscillator 3 and reflecting means 1 constitute a resonator 7. The waveguide-type device 5 is provided outside of the resonator 7. The oscillator 3 oscillates laser beam having a wavelength of 914±1 nm, and the waveguide-type device 5 oscillates blue laser “E” having a wavelength of 457±1 nm.

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 an optical waveguide part includes the steps of preparing a ferroelectric single crystalline substrate having a polarization-axis substantially parallel to a main surface thereof and having a given ferroelectric domain-inverted pattern, and epitaxially growing a ferroelectric single crystalline film on the ferroelectric single crystalline substrate. The ferroelectric domain-inverted pattern is thereby transcribed from the substrate into the ferroelectric single crystalline film to form a ferroelectric domain-inverted structure therein.

Abstract: An object of the present invention is to provide a practical device for generating blue laser beam having a wavelength of 457 nm. The present invention provides a device for generating blue laser beam. The device has a solid-state laser oscillator 3 composed of Nd-doped YVO4 crystal and having a length of not smaller than 0.1 mm and not larger than 1.0 mm, a reflecting means 6A, 6B provided in the oscillator 3, an illuminating means 1 for illuminating pump light beam to the oscillator 3, and a waveguide-type device 5 for generating harmonic wave. The oscillator 3 and reflecting means 1 constitute a resonator 7. The waveguide-type device 5 is provided outside of the resonator 7. The oscillator 3 oscillates laser beam having a wavelength of 914±1 nm, and the waveguide-type device 5 oscillates blue laser “E” having a wavelength of 457±1 nm.

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

Abstract: In a process for producing a planar body of an oxide single crystal with a &mgr; pulling-down method, a shoulder portion having a larger width is grown without any polycrystal regions, cracks or crystal deteriorations in a central portion of the planar body. A raw material of the oxide single crystal is melted in a crucible. A seed crystal is contacted to a melt of the raw material near an opening of a nozzle 13 of the crucible. Then, the melt 18 is drawn from the opening by pulling down the seed crystal to form a planar body 14A. A temperature distribution of the nozzle 13 in a direction perpendicular to the drawing direction B is controlled by supplying heat to the nozzle 13 and/or by removing heat from the nozzle 13.

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 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: A process is disclosed for producing an oxide single crystal, including 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: 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, including 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 the target to gasify molecules constituting the target by dissociation and evaporation thereof, and epitaxially growing the single-crystalline film on the foundation.

Abstract: In a process for producing a raw material powder including lithium potassium niobate for growing a single crystal of lithium potassium niobate, raw starting materials comprising lithium carbonate powder, potassium carbonate powder and niobium pentoxide powder are mixed in a solvent. The lithium carbonate powder and potassium carbonate powder are entirely dissolved into the solvent, and lithium carbonate and potassium carbonate are then deposited around the 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 producing an optical waveguide element by thermally diffusing a metal element or a metallic compound into a substrate having a photoelectric effect, includes the steps of: forming a waveguide pattern on the substrate, the waveguide pattern includes a metal element or metallic compound; forming a film on a main plane of the substrate that covers the entire waveguide pattern, the film having an electro-optic effect; and effecting the thermal diffusion of the metallic element or the metallic compound.

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 directional coupler including a substrate having a length and containing a material that exhibits electrooptic properties, the substrate being divided into a plurality of reversed polarization domains along a direction of length. At least two optical waveguides are formed in the substrate in the direction of length thereof and substantially parallel to a main surface thereof. An electrode is disposed above a portion of each optical waveguide for modulating light waves propagating through the waveguides, respectively, the electrode being divided equally by at least a portion of a boundary surface between the plurality of reversed polarization domains.

Abstract: In a process for producing a planar body of an oxide single crystal with a &mgr; pulling-down method, a shoulder portion having a larger width is grown without any polycrystal regions, cracks or crystal deteriorations in a central portion of the planar body. A raw material of the oxide single crystal is melted in a crucible. A seed crystal is contacted to a melt of the raw material near an opening of a nozzle 13 of the crucible. Then, the melt 18 is drawn from the opening by pulling down the seed crystal to form a planar body 14A. A temperature distribution of the nozzle 13 in a direction perpendicular to the drawing direction B is controlled by supplying heat to the nozzle 13 and/or by removing heat from the nozzle 13.

Abstract: A method for forming a ferroelectric domain-inverted structure, having the steps of joining at least two kinds of ferroelectric material which have different spontaneous polarizations, and ferroelectric domain-inverting one of the ferroelectric materials and thereby ferroelectric domain-inverting the other ferroelectric material joined thereto.