US4668263A
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: 1985-11-04
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Granted: 1987-05-26
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Expires: 2005-11-04
Abstract
Abstract A rod-in-tube method for producing a glass preform for use in the fabrication of an optical fiber, which comprises steps of inserting a glass rod as a core material in a glass tube as a cladding material, fusing and closing one end of the cladding material, filling a gap between the core and cladding materials with an atmosphere containing at least one gaseous halogen-containing compound and then heating the core and cladding materials at a temperature not lower than 1,900° C. to collapse the gap between them and to fuse them together, from which glass preform, an optical fiber with low attenuation of light transmission is fabricated.
Inventors
- 👤 Hiroshi Yokota
- 👤 Gotaro Tanaka
- 👤 Hiroo Kanamori
- 👤 Futoshi Mizutani
- 👤 Toshio Danzuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:44
CPC Classifications
C; C03; C03B; C03B37/00; C03B37/01; C03B37/012; C03B37/01205; C03B37/01211; Y; Y10; Y10S; Y10S65/00; Y10S65/15; Y10S65/16; Y10S65/90
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
182 words
A rod-in-tube method of producing a glass preform suitable for use in the fabrication of an optical fiber, said method comprising the steps of: (a) inserting a core-material glass rod in a cladding-material glass tube; (b) fusing and closing the end portion of one end of the cladding-material glass tube while filling a gap between the core-material glass rod and the cladding-material glass tube with a vapor containing at least one gaseous halogen-containing compound; (c) immediately prior to fusing the entire circumference of said end portion of the cladding-material glass tube with the core-material glass rod, opening a valve connected to a feed system for performing said filling and to an exhaust system and adjusting the flow of the gaseous halogen-containing compound by exhausting some of the vapor being fed toward the gap any further increase of the pressure in the gap; and (d) heating the core-material glass rod and the cladding-material glass tube at a temperature not lower than 1,900° C. in order to collapse the gap between the core-material glass rod and the cladding-material glass tube and fuse them together.
Claim 2
Dependent Claim
182 words
A rod-in-tube method of producing a glass preform suitable for use in the fabrication of an optical fiber, said method comprising the steps of: (a) inserting a core-material glass rod in a cladding-material glass tube; (b) fusing and closing the end portion of one end of the cladding-material glass tube while filling a gap between the core-material glass rod and the cladding-material glass tube with a vapor containing at least one gaseous halogen-containing compound; (c) immediately prior to fusing the entire circumference of said end portion of the cladding-material glass tube with the core-material glass rod, opening a valve connected to a feed system for performing said filling and to an exhaust system and adjusting the flow of the gaseous halogen-containing compound by exhausting some of the vapor being fed toward the gap any further increase of the pressure in the gap; and (d) heating the core-material glass rod and the cladding-material glass tube at a temperature not lower than 1,900° C. in order to collapse the gap between the core-material glass rod and the cladding-material glass tube and fuse them together.
Claim 3
Dependent Claim
42 words
The rod-in-tube method according to claim 1, wherein the halogen-containing compound is at least one of SF 6 , CCl 2 F 2 , CF 4 , SiF 4 , NF 3 , F 2 , Cl 2 and SOCl 2 .
Claim 4
Dependent Claim
35 words
The rod-in-tube method according to claim 1, wherein an inner surface of the cladding material glass tube is etched with a gas comprising a fluorine-containing compound prior to the insertion of the core-material glass rod.
Claim 5
Dependent Claim
16 words
The rod-in-tube method according to claim 3, wherein the etching gas further comprises a chlorine-containing compound.
Claim 6
Dependent Claim
31 words
The rod-in-tube method according to claim 1, wherein the core-material glass rod is inserted in the cladding-material glass tube while the gaseous halogen-containing compound is injected in the cladding-material glass tube.
Claim 7
Dependent Claim
15 words
The rod-in-tube method according to claim 5, wherein the halogen-containing compound is a chlorine-containing compound.
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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) | 1990-05-25 | 1990-11-24 | 1991-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-25 | 1994-11-24 | 1995-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-25 | 1998-11-24 | 1999-05-26 | $7700.00 | Window Closed / Lapsed |