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Patent US4846867A successfully refreshed from Google Patents.
US4846867A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing glass preform for optical fiber
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1988-03-11
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Granted: 1989-07-11
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Expires: 2008-03-11
Abstract
Abstract A method for producing a glass preform for use in the fabrication of an optical fiber which comprises inserting a core rod made of quartz glass in a cladding tube made of quartz glass added with fluorine, heating them from the outside of the cladding tube to fuse them together to form a primary glass preform comprising a core rod and a first cladding layer around the core rod, depositing SiO2 soot particles around the primary glass preform and thermally treating the soot deposited glass preform in the presence of a fluorine-containing compound to form a final glass preform from which an optical fiber is fabricated. From the glass preform produced by this method, an optical fiber having low attenuation of light transmission in a wide range of wave-length is fabricated.
Inventors
- 👤 Hiroshi Yokota
- 👤 Hiroo Kanamori
- 👤 Yoichi Ishiguro
- 👤 Futoshi Mizutani
- 👤 Gotaro Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:01
CPC Classifications
C; C03; C03B; C03B37/00; C03B37/01; C03B37/012; C03B37/01205; C03B37/01225; C03B37/01248; C03B37/01211; C03B37/014; C03B2201/00; C03B2201/02; C03B2201/06; C03B2201/08; C03B2201/12; Y; Y10; Y10S; Y10S65/00; Y10S65/15; Y10S65/16
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
242 words
A method for producing a glass preform for use in the fabrication of a single mode optical fiber, comprising the steps of: inserting a core rod made of quartz glass in a cladding tube made of fluorine-containing quartz glass, heating the core rod and the cladding tube from the outside of the cladding tube while etching an inner wall surface of the cladding tube and an outer surface of the rod by a halogen-containing compound gas to heat-collapse the cladding tube onto the core rod and fusing the core rod and cladding tube together to form a primary glass preform comprising a core rod and a first cladding layer around the core rod with a cladding diameter/core diameter ratio of 3 to 7, producing SiO 2 soot particles by flame oxidation of a glass-forming raw material and depositing said SiO 2 soot particles in a semisintered state around the primary glass preform to form a second cladding and adding fluorine to the deposited SiO 2 soot in such an amount that the difference between the refractive indexes of the first and second cladding after the second cladding has been vitrified is less than 0.05%, said adding fluorine being effected by thermally treating the soot deposited glass preform in the presence of a fluorine-containing gas compound at a temperature of 1000° to 1,700° C. and vitrifying said soot by heating to form a final glass preform from which an optical fiber is fabricated.
Claim 2
Independent Claim
242 words
A method for producing a glass preform for use in the fabrication of a single mode optical fiber, comprising the steps of: inserting a core rod made of quartz glass in a cladding tube made of fluorine-containing quartz glass, heating the core rod and the cladding tube from the outside of the cladding tube while etching an inner wall surface of the cladding tube and an outer surface of the rod by a halogen-containing compound gas to heat-collapse the cladding tube onto the core rod and fusing the core rod and cladding tube together to form a primary glass preform comprising a core rod and a first cladding layer around the core rod with a cladding diameter/core diameter ratio of 3 to 7, producing SiO 2 soot particles by flame oxidation of a glass-forming raw material and depositing said SiO 2 soot particles in a semisintered state around the primary glass preform to form a second cladding and adding fluorine to the deposited SiO 2 soot in such an amount that the difference between the refractive indexes of the first and second cladding after the second cladding has been vitrified is less than 0.05%, said adding fluorine being effected by thermally treating the soot deposited glass preform in the presence of a fluorine-containing gas compound at a temperature of 1000° to 1,700° C. and vitrifying said soot by heating to form a final glass preform from which an optical fiber is fabricated.
Claim 3
Dependent Claim
17 words
The method according to claim 1, wherein the core rod is one made by the VAD method.
Claim 4
Dependent Claim
24 words
The method according to claim 1, wherein the fused core rod and cladding tube are drawn before the SiO 2 soot particles are deposited.
Claim 5
Dependent Claim
20 words
The method according to claim 1, wherein the SiO 2 particles are synthesized by flame hydrolysis of SiCl 4 .
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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) | 1992-07-10 | 1993-01-09 | 1993-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-10 | 1997-01-09 | 1997-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-10 | 2001-01-09 | 2001-07-11 | $7700.00 | Window Closed / Lapsed |