Patent US4740225A successfully refreshed from Google Patents.
US4740225A
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Method of producing optical fibers with noncircular core
Assignee: Telecom Italia SpA
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Filing: 1986-10-23
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Granted: 1988-04-26
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Expires: 2006-10-23
Abstract
Abstract A method of making optical performs from which optical fibers are drawn after collapsing of the preform, which comprises depositing by a vapor-phase reaction a plurality of layers on the inner surface of a support tube and controlling the temperature profile around the perimeter of the support so that the thickness of the deposit varies between at least one maximum and at least one minimum. Upon collapse of the support this gives rise to a core having a noncircular cross section.
Inventors
- 👤 Giuseppe Cocito
- 👤 Giorgio Grego
- 👤 Eros Modone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:01
CPC Classifications
C; C03; C03B; C03B37/00; C03B37/01; C03B37/012; C03B37/014; C03B37/018; C03B37/01884; C03B37/01807; C03B37/01815; C03B37/01892; C03B2203/00; C03B2203/10; C03B2203/12; C03B2203/30
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
182 words
A method of producing optical fibers with a noncircular core, comprising the steps of: (a) producing a preform by internally depositing on an internal surface of a tubular preform support a plurality of layers of a vitrifiable material, each generated by high-temperature synthesis from vapor-phase reactants to form a core material; (b) maintaning a temperature profile perimetrally around said support so that the layers of said core material are deposited in a thickness which varies in a predetermined pattern around the perimeter of the support between at least one maximum and at least one minimum and results from a temperature distribution varying between at least one minimum to at least one maximum in inverse correspondence to the predetermined thickness variation pattern; (c) collapsing said preform with said layers thereon in said predetermined thickness variation pattern to a circular cross section body with a solid core of said core material in a noncircular cross sectional shape determined by said thickness variation pattern; and (d) drawing an optical fiber of circular outer cross section and noncircular core cross section from the collapsed preform body.
Claim 2
Independent Claim
182 words
A method of producing optical fibers with a noncircular core, comprising the steps of: (a) producing a preform by internally depositing on an internal surface of a tubular preform support a plurality of layers of a vitrifiable material, each generated by high-temperature synthesis from vapor-phase reactants to form a core material; (b) maintaning a temperature profile perimetrally around said support so that the layers of said core material are deposited in a thickness which varies in a predetermined pattern around the perimeter of the support between at least one maximum and at least one minimum and results from a temperature distribution varying between at least one minimum to at least one maximum in inverse correspondence to the predetermined thickness variation pattern; (c) collapsing said preform with said layers thereon in said predetermined thickness variation pattern to a circular cross section body with a solid core of said core material in a noncircular cross sectional shape determined by said thickness variation pattern; and (d) drawing an optical fiber of circular outer cross section and noncircular core cross section from the collapsed preform body.
Claim 3
Dependent Claim
36 words
The method defined claim 1 wherein said temperature profile is selected so that said layers are deposited in a succession of thickness maxima alternating with thickness minima around the perimeter at each cross-section of said preform.
Claim 4
Dependent Claim
27 words
The method defined in claim 1 wherein said temperature profile is maintained in step b by hearing said support and forming said support with a noncircular cross-section.
Claim 5
Dependent Claim
21 words
The method defined in claim 3 wherein the cross section of said support has different dimensions along two mutually perpendicular axes.
Claim 6
Dependent Claim
15 words
The method defined in claim 1 wherein said support has a noncircular external cross section.
Claim 7
Dependent Claim
15 words
The method defined in claim 1 wherein said support has a noncircular internal cross section.
Claim 8
Dependent Claim
23 words
The method defined in claim 1 wherein said support has walls of constant wall thickness along the perimeter of any cross section thereof.
Claim 9
Dependent Claim
23 words
The method defined in claim 1 wherein said support varies in thickness around the perimeter of said support at any cross section thereof.
Claim 10
Dependent Claim
29 words
The method defined in claim 1, further comprising the step of positioning at least one rod along said tubular support and incorporating said rod with said tube upon heating.
Claim 11
Dependent Claim
27 words
The method defined in claim 9 wherein at least four rods, having two by two different cross-sectional size, are positioned along and incorporated with said tubular support.
Claim 12
Dependent Claim
30 words
The method defined in claim 3 wherein the temperature profile is maintained in step b by varying the tube section shape by acting on the pressure inside said tubular support.
Claim 13
Dependent Claim
50 words
The method defined in claim 1 wherein the temperature profile is maintained in step b by interposing between a heat source and said support a screening refractory element which encloses said support and is formed with at least one slit extending substantially over the entire length of the screening element.
Claim 14
Dependent Claim
21 words
The method defined in claim 12 wherein said screening element is formed with a plurality of slits having the same widths.
Claim 15
Dependent Claim
18 words
The method defined in claim 12 wherein said element has a plurality of such slits with different widths.
Claim 16
Dependent Claim
19 words
The method defined in claim 12 wherein said element is formed with portions between slits of the same widths.
Claim 17
Dependent Claim
18 words
The method defined in claim 12 wherein said element is formed with portions between slits of different widths.
Claim 18
Dependent Claim
18 words
The method defined in claim 12 wherein said element is formed with portions between slits of different thicknesses.
Claim 19
Dependent Claim
16 words
The method defined in claim 12 wherein said element is formed between slits of different shapes.
Claim 20
Dependent Claim
20 words
The method defined in claim 12 wherein said element is formed with portions between slits of different thicknesses and shapes.
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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) | 1991-04-26 | 1991-10-26 | 1992-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-26 | 1995-10-26 | 1996-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-26 | 1999-10-26 | 2000-04-26 | $7700.00 | Window Closed / Lapsed |