US4282196A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing optical fibers of silica
Assignee: AT&T Inc
•
Filing: 1979-10-12
•
Granted: 1981-08-04
•
Expires: 1999-10-12
Abstract
Abstract A hydrolysis method of purifying silicon tetrachloride is shown that reduces losses in optical fibers made from silica produced therefrom. Water is added to impure liquid silicon tetrachloride, which forms a gel which is then separated from the remaining SiCl 4 . Metal impurities, OH-containing impurities, and SiHCl 3 are removed by this process. In a preferred embodiment, the water is added by bubbling a wet gas through the SiCl 4 . A residual amount of OH containing impurities and HCl is left after the hydrolysis, which impurities may be further removed by a refluxing technique.
Inventors
- 👤 Thomas Y. Kometani
- 👤 Darwin L. Wood
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:22
CPC Classifications
C; C03; C03C; C03C1/00; C03C1/02; C03C1/022; C01; C01B; C01B33/00; C01B33/08; C01B33/107; C01B33/10778; C01B33/10784; C01B33/10789; Y; Y10; Y10S; Y10S65/00; Y10S65/901
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
120 words
A method of making an optical fiber by steps comprising oxidizing silicon tetrachloride to form silica, CHARACTERIZED by the additional step of purifying prior to oxidation impure liquid silicon tetrachloride by steps comprising adding water to said impure liquid silicon tetrachloride and separating the gel formed thereby from the remaining silicon tetrachloride, with the amount of the added water being less than 25 weight percent of said impure liquid silicon tetrachloride, and thereafter forming an optical fiber comprising silica produced by the oxidation of said remaining silicon tetrachloride, and further characterized in that said water is added in sufficient amount so that the concentration of OH-containing impurities in said remaining silicon tetrachloride is approximately 95 parts per million by weight.
Claim 2
Independent Claim
120 words
A method of making an optical fiber by steps comprising oxidizing silicon tetrachloride to form silica, CHARACTERIZED by the additional step of purifying prior to oxidation impure liquid silicon tetrachloride by steps comprising adding water to said impure liquid silicon tetrachloride and separating the gel formed thereby from the remaining silicon tetrachloride, with the amount of the added water being less than 25 weight percent of said impure liquid silicon tetrachloride, and thereafter forming an optical fiber comprising silica produced by the oxidation of said remaining silicon tetrachloride, and further characterized in that said water is added in sufficient amount so that the concentration of OH-containing impurities in said remaining silicon tetrachloride is approximately 95 parts per million by weight.
Claim 3
Dependent Claim
17 words
The method of claim 1 FURTHER CHARACTERIZED by adding said water by means of a wet gas.
Claim 4
Independent Claim
38 words
The method of claims 1 or 2 FURTHER CHARACTERIZED by the further steps comprising reducing the amount of OH containing impurities and HCl in said remaining silicon tetrachloride to less than 50 parts per million by weight each.
Claim 5
Dependent Claim
53 words
The method of claim 14 FURTHER CHARACTERIZED by effecting said reducing the amount of OH-containing impurities and HCl by heating said remaining silicon tetrachloride to approximately its boiling point in a vessel having an opening, so that at least a portion of said remaining silicon tetrachloride condenses on the interior of said vessel.
Claim 6
Dependent Claim
30 words
The method of claim 4 FURTHER CHARACTERIZED by passing a dry gas across said opening of said vessel to aid in said reducing the amount of OH-containing impurities and HCl.
Claim 7
Dependent Claim
16 words
The method of claim 1 FURTHER CHARACTERIZED in that said water is heavy water comprising deuterium.
References Cited (Backward Citations)
DE1356135U
Cited
US2820698A
Cited
DE1046582B
Cited
US2977198A
Cited
US3071444A
Cited
DE1138746B
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-03 | 1985-02-02 | 1985-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-03 | 1989-02-02 | 1989-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-03 | 1993-02-02 | 1993-08-04 | $7700.00 | Window Closed / Lapsed |