US4648891A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical fiber
Assignee: Corning Inc
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Filing: 1985-04-08
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Granted: 1987-03-10
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Expires: 2005-04-08
Abstract
Abstract A tubular porous silica preform is made by depositing particulate silica on a mandrel from which the preform is subsequently removed. A solid cylindrical porous silica preform is made by depositing particulate silica on an end surface of a support body. The porous preforms are then dried and the tubular preform is heated in a fluorine containing atmosphere to introduce a fluorine dopant into the silica. The rod preform is then placed inside the tubular preform and the two preforms are further dried in a chlorine atmosphere to remove residual moisture. The dual preforms are then heated in a zone sintering furnace to consolidate and collapse the porous material of the rod and tubular preforms into a transparent fused silica rod. The composite preform obtained is heated and dielectric optical waveguide drawn from it, the waveguide having a pure silica or doped silica core derived from the rod preform and a fluorine doped silica cladding derived from the tubular preform.
Inventors
- 👤 Koichi Abe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:40
CPC Classifications
C; C03; C03B; C03B37/00; C03B37/01; C03B37/012; C03B37/014; C03B37/01446; C03B37/01205; C03B37/01211; C03B37/01466; C03B37/01473; C03C; C03C13/00; C03C13/04; C03C13/045; C03B2201/00; C03B2201/06; C03B2201/08; C03B2201/12; Y; Y10; Y10S; Y10S65/00; Y10S65/15; Y10S65/16
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
161 words
A method of making an optical waveguide comprising: making a porous pure silica cylindrical rod preform by depositing particulate silica onto a support body; cooling and then removing the preform rod from the support body; making a porous pure silica hollow cylindrical preform by depositing particulate silica onto a second support body; cooling the hollow cylindrical preform; and removing the support body; drying the preforms; heating the hollow cylindrical preform in a fluorine-containing atmosphere to cause diffusion of fluorine thereinto; putting the cylindrical rod preform into the hollow cylindrical preform; heating the preforms to cause consolidation of the porous silica and to cause collapse of the hollow preform onto the rod preform to form a composite preform; heating the composite preform locally to a drawing temperature; and drawing an optical waveguide from the composite preform, such waveguide having a core part comprising silica derived from the rod preform and a cladding part comprising fluorine doped silica derived from the hollow preform.
Claim 2
Independent Claim
161 words
A method of making an optical waveguide comprising: making a porous pure silica cylindrical rod preform by depositing particulate silica onto a support body; cooling and then removing the preform rod from the support body; making a porous pure silica hollow cylindrical preform by depositing particulate silica onto a second support body; cooling the hollow cylindrical preform; and removing the support body; drying the preforms; heating the hollow cylindrical preform in a fluorine-containing atmosphere to cause diffusion of fluorine thereinto; putting the cylindrical rod preform into the hollow cylindrical preform; heating the preforms to cause consolidation of the porous silica and to cause collapse of the hollow preform onto the rod preform to form a composite preform; heating the composite preform locally to a drawing temperature; and drawing an optical waveguide from the composite preform, such waveguide having a core part comprising silica derived from the rod preform and a cladding part comprising fluorine doped silica derived from the hollow preform.
Claim 3
Dependent Claim
49 words
A method as claimed in claim 1 in which the hollow cylindrical preform is made by depositing particulate silica obtained from the flame hydrolysis of a silicon halide onto the curved surface of a mandrel and subsequently removing the hollow cylindrical preform from the mandrel upon cooling the preform.
Claim 4
Dependent Claim
37 words
A method as claimed in claim 1 in which the rod preform is made by axial deposition of particulate silica obtained from the flame hydrolysis of a silicon halide onto the end surface of a seed rod.
Claim 5
Dependent Claim
23 words
A method as claimed in claim 1 in which the steps of deposition of particulate silica comprise chemical vapor deposition of silicon tetrachloride.
Claim 6
Dependent Claim
28 words
A method as claimed in claim 1 in which the fluorine is derived from a fluoride gas fed to he hollow cylindrical preform in conjunction with helium gas.
Claim 7
Dependent Claim
24 words
A method as claimed in claim 5, in which the fluoride gas is one of the group consisting of sulphur hexafluoride and silicon tetrafluoride.
Claim 8
Dependent Claim
55 words
A method as claimed in claim 1 in which following insertion of the rod preform into the hollow cylindrical preform, the rod and hollow cylindrical preforms are subjected to chlorine drying in a first part of a furnace and the subsequent consolidation and collapse is effected in a second higher temperature part of the furnace.
References Cited (Backward Citations)
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GB2037273A
Cited
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Cited
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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) | 1990-03-09 | 1990-09-08 | 1991-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-09 | 1994-09-08 | 1995-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-09 | 1998-09-08 | 1999-03-10 | $7700.00 | Window Closed / Lapsed |