Patent US5371812A successfully refreshed from Google Patents.
US5371812A
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Waveguide type optical directional coupler
Assignee: Ibiden Co Ltd
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Filing: 1993-11-22
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Granted: 1994-12-06
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Expires: 2013-11-22
Abstract
Abstract Down-sized optical directional coupler with high performance and reduction of power includes a LiTaO 3 monocrystal substrate, at least two optical waveguides of a LiNbO 3 monocrystalline thin film formed close to and parallel to each other, and means for changing a refractive index of the optical waveguide provided on at least one of the optical waveguides, thereby obtaining a matching of a lattice constant between the LiTaO 3 monocrystal substrate and the LiNbO 3 monocrystalline thin film.
Inventors
- 👤 Masanori Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:28
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/03; G02F1/035; G02F1/29; G02F1/31; G02F1/313; G02F1/3132; G02F2201/00; G02F2201/07; G02F2202/00; G02F2202/20
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
77 words
An optical directional coupling comprising: a LiTaO 3 monocrystal substrate; a plurality of optical waveguides of a LiNbO 3 monocrystalline thin film formed close to and parallel to each other, with lattice constants of the LiTaO 3 monocrystal substrate and the LiNbO 3 monocrystalline thin film being matched to each other; and refractive index changing means provided on at least one of said optical waveguides for changing a refractive index of the at least one optical waveguide.
Claim 2
Dependent Claim
77 words
An optical directional coupling comprising: a LiTaO 3 monocrystal substrate; a plurality of optical waveguides of a LiNbO 3 monocrystalline thin film formed close to and parallel to each other, with lattice constants of the LiTaO 3 monocrystal substrate and the LiNbO 3 monocrystalline thin film being matched to each other; and refractive index changing means provided on at least one of said optical waveguides for changing a refractive index of the at least one optical waveguide.
Claim 3
Dependent Claim
29 words
The optical directional coupling as claimed in claim 1, wherein said substrate has a surface, and the plurality of optical waveguides are formed on the surface of the substrate.
Claim 4
Dependent Claim
32 words
The optical directional coupling as claimed in claim 1, wherein said substrate has a surface, and the plurality of optical waveguides are formed in a groove on the surface of the substrate.
Claim 5
Dependent Claim
36 words
The optical directional coupling as claimed in claim 1, wherein the lattice constant of the LiNbO 3 monocrystalline thin film is within a range of 99.81˜100.07% of the lattice constant of the LiTaO 3 monocrystal substrate.
Claim 6
Dependent Claim
36 words
The optical directional coupling as claimed in claim 1, wherein the lattice constant of the LiNbO 3 monocrystalline thin film is within a range of 99.92˜100.073% of the lattice constant of the LiTaO 3 monocrystal substrate.
Claim 7
Dependent Claim
47 words
The optical directional coupling as claimed in claim 1, wherein the lattice matching is with respect to "a" axis of (0001) face of a surface of the LiTaO 3 monocrystal substrate and "a" axis of (0001) face of a surface of the LiNbO 3 monocrystalline thin film.
Claim 8
Dependent Claim
26 words
The optical directional coupling as claimed in claim 1, wherein the means for changing the refractive index of the optical waveguide comprises at least one electrode.
Claim 9
Dependent Claim
32 words
The optical directional coupling as claimed in claim 7, further comprising an SiO 2 buffer layer between at least one of the plurality of optical waveguides and the at least one electrode.
Claim 10
Dependent Claim
27 words
The optical directional coupling as claimed in claim 7, wherein said at least one electrode comprises an electrode associated with each of said plurality of optical waveguides.
Claim 11
Dependent Claim
28 words
The optical directional coupling as claimed in claim 9, further comprising an SiO 2 buffer layer between each of the plurality of optical waveguides and the associated electrode.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-12-05 | 1998-06-06 | 1998-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-12-05 | 2002-06-06 | 2002-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-12-05 | 2006-06-06 | 2006-12-06 | $7700.00 | Window Closed / Lapsed |