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1.发明专利
公开(公告)号：JP2002072266A
公开(公告)日：2002-03-12
申请号：JP2000255102
申请日：2000-08-25
Applicant: NAT INST FOR MATERIALS SCIENCE , FURUKAWA YASUNORI , KITAMURA KENJI , TAKEGAWA SHUNJI
Inventor： FURUKAWA YASUNORI , KITAMURA KENJI , TAKEGAWA SHUNJI
Abstract: PROBLEM TO BE SOLVED: To provide an optical functional element in which the controllability of a polarization inversion structure is improved and the resistance against optical damage is further improved. SOLUTION: The following optical elements (1) to (3) or the like can be realized by using a single crystal of lithium tantalate having nearly a stoichiometric composition with excess Li and 0.500 to 0.505 mole fraction of Li2O/(Ta2O5+Li2O) for the substrate. The elements are (1) an optical functional element which converts the wavelength of incident laser light having the wavelength in the visible to near IR region into shorter or longer wavelength by periodically reversing the polarization structure of the lithium tantalite single crystal, (2) an optical memory element or optical circuit element to record various kinds of information in the single crystal by forming polarization reversal in a minute region in the lithium tantalate single crystal in a single polarization state, and (3) an optical element which controls the laser light incident to the single crystal by using the electro-optical effect of the single crystal and which deviates, focuses or switches the light by using the large change in the refractive index in the reversal structure of the ferroelectric polarization of the lithium tantalite single crystal.
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2.发明专利
公开(公告)号：JP2003267798A
公开(公告)日：2003-09-25
申请号：JP2000341132
申请日：2000-11-08
Applicant: NAT INST FOR MATERIALS SCIENCE , FURUKAWA YASUNORI , KITAMURA KENJI , TAKEGAWA SHUNJI
Inventor： FURUKAWA YASUNORI , KITAMURA KENJI , TAKEGAWA SHUNJI , MIYAMOTO AKIO , TERAO MASAKI , SUDA NOBORU
Abstract: PROBLEM TO BE SOLVED: To provide a method for improving the element performance of a lithium niobate single crystal which has been expected as the material for optical elements because it has excellent optical properties and a single crystal having a large diameter and high uniformity of composition can be supplied relatively easily, but has been limited in the improvement of the element performance due to the congruent composition containing several percents of non- stoichiometric defects in the conventional commercial lithium niobate single crystals. SOLUTION: The lithium niobate single crystal is grown from a melt having a composition containing Li more than the stoichiometric composition. The lithium niobate single crystal contains 0.1-3 mol% of at least one element of Mg, Zn, Sc and In. The lithium single crystal has a molar fraction of the formula: Li 2 O/(Nb 2 O 5 +Li 2 O) of from 0.490 to less than 0.500. The optical device using the lithium niobate single crystal and a method for producing the same are also provided. COPYRIGHT: (C)2003,JPO
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公开(公告)号：JP2002196381A
公开(公告)日：2002-07-12
申请号：JP2000391214
申请日：2000-12-22
Applicant: MATSUSHITA ELECTRIC IND CO LTD , NAT INST FOR MATERIALS SCIENCE , KITAMURA KENJI , FURUKAWA YASUNORI , TAKEGAWA SHUNJI , NAKAMURA MASARU
Inventor： MIZUUCHI KIMINORI , YAMAMOTO KAZUHISA , KITAMURA KENJI , FURUKAWA YASUNORI , TAKEGAWA SHUNJI , NAKAMURA MASARU
IPC: G02F1/377
Abstract: PROBLEM TO BE SOLVED: To provide a high-efficiency structure of an optical wavelength converting element in which inhomogeneity in the polarization inversion structure due to processes of forming an optical waveguide is prevented by repeating part of the periodical polarization inversion structure formed in a stoichiometric LN crystal to stabilize the structure. SOLUTION: The optical wavelength converting element has a stoichiometric LiNbO3 crystal substrate 1 having 49.5 to 50.2% molar ratio of Li2O/(Nb2O5+Li2 O) and a polarization inversion part 2 formed on the surface of the crystal. The polarization inversion part 2 is periodically arranged, at least part of which being formed in contact with each other by repetition. A comb-like electrode is formed on the surface of the substrate 1, a flat electrode is formed on the back face of the substrate and a voltage is applied between the electrodes to grow the polarization inversion from the comb-like electrode. The polarization inversed part and its continuous part are formed inward in the crystal. Then a proton exchange optical waveguide 3 is formed by proton exchanging and annealing.
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公开(公告)号：JP2003177258A
公开(公告)日：2003-06-27
申请号：JP2001376441
申请日：2001-12-10
Inventor： NAKAJIMA HIROKI , YUKI MASAHIRO , OKA TAKAHIRO , YAMAUCHI HIROSHI , KITAMURA KENJI , KURIMURA SUNAO
Abstract: PROBLEM TO BE SOLVED: To provide an optical element which utilizes an electro-optic effect of lithium niobate, has a short element length and has a low driving voltage. SOLUTION: The optical element 1 has a lithium niobate crystal substrate 11 with a stoichiometric composition. The lithium niobate crystal substrate 11 has a titanium diffusion layer 13 to be a wave guide formed in the vicinity of a surface 12, has the short element length, has the low driving voltage and hence is excellent in a degree of integration. COPYRIGHT: (C)2003,JPO
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公开(公告)号：JP2002167299A
公开(公告)日：2002-06-11
申请号：JP2000363532
申请日：2000-11-29
Applicant: HITACHI METALS LTD , NAT INST FOR MATERIALS SCIENCE
Inventor： MIYAMOTO AKIO , KITAMURA KENJI , FURUKAWA YASUNORI , TAKEGAWA SHUNJI
Abstract: PROBLEM TO BE SOLVED: To provide a method of manufacturing a single crystal of LiNb1-xTaxO3 (0 =30 wt.% has particle size of >=500 μm.
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Patent Agency Ranking
公开(公告)号：JP2002167297A
公开(公告)日：2002-06-11
申请号：JP2000363531
申请日：2000-11-29
Applicant: HITACHI METALS LTD , NAT INST FOR MATERIALS SCIENCE
Inventor： MIYAMOTO AKIO , KITAMURA KENJI , FURUKAWA YASUNORI , TAKEGAWA SHUNJI
Abstract: PROBLEM TO BE SOLVED: To provide an optical device which is highly efficient at a wavelength of about 300 nm, and a stable optical device using the above. SOLUTION: The lithium tantalate single crystal is grown in a melt which contains more Li than its proportional composition. Na content in the crystal is
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7.发明专利
公开(公告)号：JP2001287999A
公开(公告)日：2001-10-16
申请号：JP2000341130
申请日：2000-11-08
Applicant: NAT INST FOR MATERIALS SCIENCE , FURUKAWA YASUNORI , KITAMURA KENJI , TAKEGAWA SHUNJI
Inventor： FURUKAWA YASUNORI , KITAMURA KENJI , TAKEGAWA SHUNJI , MIYAMOTO AKIO , TERAO MASAKI , SUDA NOBORU
Abstract: PROBLEM TO BE SOLVED: To solve the problem that the improvement of the device performance is limited because an available conventional lithium tantalate single crystal has a congruent composition including several percentage of disproportionation defect although the lithium tantalate single crystal is expected as a material for an optical element because the single crystal having excellent optical characteristics, a large caliber and high composition homogeneity can be supplied at a comparatively inexpensive price. SOLUTION: This lithium tantalate single crystal grown from a molten liquid having a composition containing excess Li compared to the fixed ratio composition, and having >=0.490 and
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公开(公告)号：JP2003171199A
公开(公告)日：2003-06-17
申请号：JP2001365912
申请日：2001-11-30
Applicant: NAT INST FOR MATERIALS SCIENCE
Inventor： KITAMURA KENJI , TAKEGAWA SHUNJI , NAKAMURA MASARU , FURUKAWA YASUNORI , KAKIMOTO KOICHI
Abstract: PROBLEM TO BE SOLVED: To provide a mean for surely manufacturing a single crystal having a large diameter and free from inclusions. SOLUTION: A lithium niobate single crystal or lithium tantalate single crystal having a large diameter and free from inclusions such as air bubbles is obtained by applying an accelerated crucible rotation technique (ACRT) comprising changing the rotation number or the rotation direction of a crucible to a single crystal growth technique based on a double crucible method, and thereby, controlling the movement of the crucible and enhancing the agitation effect. COPYRIGHT: (C)2003,JPO
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公开(公告)号：JP2002072267A
公开(公告)日：2002-03-12
申请号：JP2000255253
申请日：2000-08-25
Applicant: NAT INST FOR MATERIALS SCIENCE , FURUKAWA YASUNORI , KITAMURA KENJI , TAKEGAWA SHUNJI , NAKAMURA MASARU
Inventor： FURUKAWA YASUNORI , KITAMURA KENJI , TAKEGAWA SHUNJI , NAKAMURA MASARU
Abstract: PROBLEM TO BE SOLVED: To highly precisely and uniformly form a polarization inversion struc ture without any optical distortion. SOLUTION: The optical functional element is obtained by forming the polarization inversion structure at the temperature lower than the Curie temperature by using an electron beam scanning irradiation method or voltage application method in a part of a ferroelectric single crystal substrate preparedly using LiNbO3 crystal having 0.95 to 1.01 molar ratio of Li/Nb as the substrate, and the optical functional element controls the light passing through the polarization inversion part. By this method,
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公开(公告)号：JP2001264554A
公开(公告)日：2001-09-26
申请号：JP2000075318
申请日：2000-03-17
Applicant: MATSUSHITA ELECTRIC IND CO LTD , NAT INST FOR MATERIALS SCIENCE , KITAMURA KENJI , FURUKAWA YASUNORI , TAKEGAWA SHUNJI
Inventor： MIZUUCHI KIMINORI , YAMAMOTO KAZUHISA , KITAMURA KENJI , FURUKAWA YASUNORI , TAKEGAWA SHUNJI
Abstract: PROBLEM TO BE SOLVED: To provide an optical device that a large change amount in the refractive index can be obtained by using a proton exchange layer formed in a stoichiometric LN crystal, the characteristics of the optical device are improved, the scattering loss in the proton exchange layer is decreased and the optical constant in the proton exchange layer is improved. SOLUTION: The optical device has a nearly stoichiometric LiNbPO3 crystal substrate having the molar ratio of Li/Nb ranging from 0.95 to 1.01 and a proton exchange layer formed near the surface of the crystal. The proton exchange is performed by dipping the substrate in a heated pyrophosphoric acid. The surface layer of the LiNbO3 crystal substrate is exchanged with protons (H+) to form HLiNbO3 and a large difference in the refractive index between the LN crystal substrate and the proton exchange layer is obtained.
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