US4738873A
Expired / Lapsed
US
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Method of making alumina-doped silica optical fibers
Assignee: Telecom Italia SpA
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Filing: 1986-03-28
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Granted: 1988-04-19
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Expires: 2006-03-28
Abstract
Abstract The method allows the production of silica and dopant with reactions among gaseous chemical compounds. The optical fibers produced do not present dip and exhibit low attenuation. Carbon dioxide is used as the oxidizer and organometallic aluminum compounds are used to obtain the dopant; silica is obtained from organometallic silicon compounds or silicon tetrachloride.
Inventors
- 👤 Giacomo Roba
- 👤 Giuseppe Parisi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:51
CPC Classifications
C; C03; C03C; C03C13/00; C03C13/04; C03C13/045
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
114 words
A method of making silica fibers doped with alumina, comprising the steps of: providing a silica glass optical fiber preform as a support; reacting silicon tetrachloride or at least one gaseous organometallic silicon compound easily vaporizable at room temperature and at least one gaseous organometallic aluminum-containing dopant-producing compound selected from the group which consists of Al(CH 3 ) 3 , Al(C 2 H 5 ) 3 , AlCl(CH 3 ) 2 and AlCl(C 2 H 5 ) 2 with carbon dioxide as an oxidizer to codeposit by modified chemical vapor deposition silica and alumina upon said silica glass optical fiber preform support to form a coated body; and drawing optical fibers from said body.
Claim 2
Independent Claim
114 words
A method of making silica fibers doped with alumina, comprising the steps of: providing a silica glass optical fiber preform as a support; reacting silicon tetrachloride or at least one gaseous organometallic silicon compound easily vaporizable at room temperature and at least one gaseous organometallic aluminum-containing dopant-producing compound selected from the group which consists of Al(CH 3 ) 3 , Al(C 2 H 5 ) 3 , AlCl(CH 3 ) 2 and AlCl(C 2 H 5 ) 2 with carbon dioxide as an oxidizer to codeposit by modified chemical vapor deposition silica and alumina upon said silica glass optical fiber preform support to form a coated body; and drawing optical fibers from said body.
Claim 3
Dependent Claim
74 words
The method defined in claim 1 wherein said silicon-containing compound is selected from the group which consists of: Si(C.sub.a H.sub.b).sub.d, Si(C.sub.a H.sub.b).sub.e X.sub.s, and Si(C.sub.a H.sub.b).sub.f O.sub.t, wherein X is halogen, a and b are numbers representing the number of atoms per hydrocarbon moiety, d, e and f are numbers representing the number of hydrocarbon moieties per molecule, and s and t are numbers representing the number of halogen and oxygen atoms per molecule.
Claim 4
Dependent Claim
30 words
The method defined in claim 1 wherein said silicon-containing compound is silicon tetrachloride and the silicon tetrachloride is reacted with said carbon dioxide to yield the silica of said layer.
Claim 5
Dependent Claim
16 words
The method defined in claim 1 wherein CO 2 is the sole oxidizer of said compounds.
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) | 1991-04-19 | 1991-10-19 | 1992-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-19 | 1995-10-19 | 1996-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-19 | 1999-10-19 | 2000-04-19 | $7700.00 | Window Closed / Lapsed |