Patent US4673241A successfully refreshed from Google Patents.
US4673241A
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Diffraction gratings and optical branching filter elements
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1985-10-10
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Granted: 1987-06-16
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Expires: 2005-10-10
Abstract
Abstract An optical branching filter element comprised of a substrate having a wave guide thereon of a material capable of reversibly changing its refractive index and an erasable diffraction grating formed on the waveguide. The diffraction grating may be formed by a holographic exposure method or a light beam scanning method and may be erased by suitable erasing means.
Inventors
- 👤 Yoshikazu Nishiwaki
- 👤 Shunji Matsuoka
- 👤 Kenji Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:28
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70408; G02; G02B; G02B5/00; G02B5/32; G02B6/00; G02B6/10; G02B6/12; G02B6/122; G02B6/124; G03F7/0005; G03F7/001; G03F7/20; G03F7/2002; G03F7/2004; G03F7/2006; G03H; G03H1/00; G03H1/04
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
66 words
An optical branching filter element comprising a substrate a waveguide provided on the substrate, said waveguide being made of a material capable of reversibly changing its refractive index on application of light and serving to guide light in a plane, and a diffraction grating formed on the waveguide by a holographic exposure method or a light beam scanning method and erasable by suitable erasing means, respectively.
Claim 2
Dependent Claim
66 words
An optical branching filter element comprising a substrate a waveguide provided on the substrate, said waveguide being made of a material capable of reversibly changing its refractive index on application of light and serving to guide light in a plane, and a diffraction grating formed on the waveguide by a holographic exposure method or a light beam scanning method and erasable by suitable erasing means, respectively.
Claim 3
Dependent Claim
23 words
The optical branching filter element as claimed in claim 1, wherein the material of which the waveguide is made is an electro-optic crystal.
Claim 4
Dependent Claim
28 words
The optical branching filter element as claimed in claim 2 wherein the electro-optic crystal is Bi 12 SiO 20 (bismuth siliconoxide) or Bi 12 GeO 20 (bismuth germaniumoxide).
Claim 5
Dependent Claim
23 words
The optical branching filter element as claimed in claim 1 wherein the material of which the waveguide is made is an amorphous semiconductor.
Claim 6
Dependent Claim
22 words
The optical branching filter element as claimed in claim 4, wherein the amorphous semiconductor is As-S, As-S-Ge, or As-S-Se-Ge based chalcogenide glass.
Claim 7
Dependent Claim
23 words
The optical branching filter element as claimed in claim 1, wherein the material of which the waveguide is made is a thermoplastic material.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-15 | 1990-12-15 | 1991-06-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-15 | 1994-12-15 | 1995-06-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-15 | 1998-12-15 | 1999-06-16 | $7700.00 | Window Closed / Lapsed |