Patent US6375625B1 successfully refreshed from Google Patents.
US4184744A
Expired / Lapsed
US
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Optical fiber
Assignee: Hitachi Cable Ltd
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Filing: 1976-11-01
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Granted: 1980-01-22
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Expires: 1996-11-01
Abstract
Abstract In order to make the transmission loss of the lowest order leaky mode over the transmission length 10dB or more, an optical fiber for optical transmission is constructed of a cladding layer whose refractive index is constant, an intermediate layer which has a constant refractive index lower than the refractive index of the cladding layer, and a core whose refractive index is continuously varied so as to be the highest at the central part and to be substantially equal to that of the cladding layer at the peripheral part, and the thickness of the intermediate layer is 0.1-1 times the radius of the core.
Inventors
- 👤 Seiichi Onoda
- 👤 Toshiki P. Tanaka
- 👤 Masao Sumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:50
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/02; G02B6/036; G02B6/03616; G02B6/03622; G02B6/03627; G02B6/028; G02B6/0288
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
150 words
An optical fiber comprising: a cylindrical core of dielectric material having an index of refraction which varies in the radial direction of the core; an intermediate layer disposed on said core and being made of a dielectric material which has a uniform index of refraction; a cladding layer disposed on said intermediate layer and being made of a dielectric material which has a uniform index of refraction higher than the index of refraction of said intermediate layer, and wherein the index of refraction of said core at the central portion thereof is higher than the indices of refraction of said cladding layer and said intermediate layer, and the index of refraction of the periphery of said core is substantially equal to the index of refraction of said cladding layer, wherein the thickness of said intermediate layer lies within a range of 0.1 to 1 times the radius of the core.
Claim 2
Dependent Claim
150 words
An optical fiber comprising: a cylindrical core of dielectric material having an index of refraction which varies in the radial direction of the core; an intermediate layer disposed on said core and being made of a dielectric material which has a uniform index of refraction; a cladding layer disposed on said intermediate layer and being made of a dielectric material which has a uniform index of refraction higher than the index of refraction of said intermediate layer, and wherein the index of refraction of said core at the central portion thereof is higher than the indices of refraction of said cladding layer and said intermediate layer, and the index of refraction of the periphery of said core is substantially equal to the index of refraction of said cladding layer, wherein the thickness of said intermediate layer lies within a range of 0.1 to 1 times the radius of the core.
Claim 3
Dependent Claim
53 words
An optical fiber according to claim 1, wherein the dielectric material of said optical fiber includes silicon dioxide selectively doped with at least one compound selected from the group consisting of GeO 2 , TiO 2 , P 2 O 5 , B 2 O 3 , and Al 2 O 3 .
Claim 4
Dependent Claim
53 words
An optical fiber according to claim 2, wherein the dielectric material of said optical fiber includes silicon dioxide selectively doped with more than one compound selected from the group consisting of GeO 2 , TiO 2 , P 2 O 5 , B 2 O 3 , and Al 2 O 3 .
Claim 5
Dependent Claim
28 words
An optical fiber according to claim 1, wherein the thickness of said intermediate layer lies within a range of 0.1 to 0.5 times the radius of the core.
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) | 1983-01-21 | 1983-07-23 | 1984-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-21 | 1987-07-23 | 1988-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-21 | 1991-07-23 | 1992-01-22 | $7700.00 | Window Closed / Lapsed |