US4636235A
Expired / Lapsed
US
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Method for producing optical fibers
Assignee: Alcatel Lucent SAS
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Filing: 1985-05-23
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Granted: 1987-01-13
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Expires: 2005-05-23
Abstract
Abstract A process is disclosed for producing an optical fiber comprising forming a tubular glass body having at least one doped layer, at least one concentric layer, each layer having a different index of refraction, and a hollow center. The glass body is heated until the softening point is reached, and is then drawn into a glass fiber. During drawing, a partial vacuum is maintained in the hollow center of the tubular glass body, the partial vacuum being of sufficient magnitude to reduce the evaporation of doping material from the interior of the tubular glass body and thereby effectively prevent a reduction in the index of refraction in the center of the optical fiber.
Inventors
- 👤 Bertram Glessner
- 👤 Paul Pitsch
- 👤 Peter Heinen
- 👤 Hartmut Peglow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:09
CPC Classifications
C; C03; C03B; C03B37/00; C03B37/01; C03B37/02; C03B37/025; C03B37/027; C03B37/012; C03B37/014; C03B37/018; C03B37/01861; C03B2205/00; C03B2205/08
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
149 words
An improved process for producing an optical fiber characterized by having essentially no reduction in index of refraction in the center of the optical fiber, comprising: forming a tubular glass body having a hollow center and at least two concentric layers, at least one interior layer being doped, each layer having an index of refraction different from at least one of said other layers; applying a partial vacuum to said hollow center of said tubular glass body; heating said tubular glass body under said partial vacuum until the softening point of said tubular glass body is reached; and drawing said softened tubular glass body under said partial vacuum into a glass fiber, said partial vacuum being of sufficient magnitude to reduce evaporation of dopant from said interior layer of said tubular glass body, thereby effectively preventing a reduction in index of refraction in the center of the optical fiber.
Claim 2
Dependent Claim
149 words
An improved process for producing an optical fiber characterized by having essentially no reduction in index of refraction in the center of the optical fiber, comprising: forming a tubular glass body having a hollow center and at least two concentric layers, at least one interior layer being doped, each layer having an index of refraction different from at least one of said other layers; applying a partial vacuum to said hollow center of said tubular glass body; heating said tubular glass body under said partial vacuum until the softening point of said tubular glass body is reached; and drawing said softened tubular glass body under said partial vacuum into a glass fiber, said partial vacuum being of sufficient magnitude to reduce evaporation of dopant from said interior layer of said tubular glass body, thereby effectively preventing a reduction in index of refraction in the center of the optical fiber.
Claim 3
Dependent Claim
14 words
The process of claim 1, wherein the glass fiber has a circular cross section.
Claim 4
Dependent Claim
26 words
The process of claim 2, wherein the tubular glass body is precollapsed before drawing, thereby ensuring its mechanical stability during drawing under less than atmospheric pressure.
Claim 5
Dependent Claim
17 words
The process of claim 3, wherein the tubular glass body is precollapsed at atmospheric pressure before drawing.
Claim 6
Dependent Claim
29 words
The process of claim 1, wherein a doped layer deficient in doping material is present in the tubular glass body and said deficient doped layer is removed before drawing.
Claim 7
Dependent Claim
22 words
The process of claim 1, wherein the evaporation of doping material from the doped layer before collapsing under low pressure is prevented.
Claim 8
Dependent Claim
20 words
The process of claim 6, wherein the tubular glass body is maintained under a pressure of less than atmospheric pressure.
Claim 9
Dependent Claim
31 words
The process of claim 7, wherein the pressure in the interior of the tubular glass body is less than the pressure acting on the outer wall of the tubular glass body.
Claim 10
Dependent Claim
32 words
The process of claim 1, wherein the at least one concentric layer having a different index of refraction from that of the doped layer comprises an essentially pure SiO 2 glass layer.
Claim 11
Dependent Claim
13 words
The process of claim 1, wherein the doped layer is a coating layer.
Claim 12
Dependent Claim
14 words
The process of claim 10, wherein the coating layer is composed of doped silicon.
Claim 13
Dependent Claim
32 words
The process of claim 11, wherein the doped silicon comprises a doping substance selected from the group consisting of germanium dioxide, phosphorus pentoxide, and a combination of germanium dioxide and phosphorus pentoxide.
Claim 14
Dependent Claim
21 words
The process of claim 1 wherein said optical fiber exhibits a maximum refractive index at the center of the optical fiber.
Claim 15
Dependent Claim
143 words
An improved process for producing an optical fiber characterized by having essentially no reduction in index of refraction in the center of the optical fiber, comprising: applying a partial vacuum to a tubular glass body having a hollow center and at least two concentric layers, at least one interior layer being doped, and each layer having an index of refraction different from at least one of said other concentric layers; heating said tubular glass body under said partial vacuum until the softening point of said tubular glass body is reached; and drawing said softened tubular glass body under said partial vaccum into a glass fiber, said partial vacuum being of sufficient magnitude to reduce evaporation of dopant from said interior doped layer of said tubular glass body, thereby effectively preventing a reduction in index of refraction in the center of the glass fiber.
Claim 16
Dependent Claim
143 words
An improved process for producing an optical fiber characterized by having essentially no reduction in index of refraction in the center of the optical fiber, comprising: applying a partial vacuum to a tubular glass body having a hollow center and at least two concentric layers, at least one interior layer being doped, and each layer having an index of refraction different from at least one of said other concentric layers; heating said tubular glass body under said partial vacuum until the softening point of said tubular glass body is reached; and drawing said softened tubular glass body under said partial vaccum into a glass fiber, said partial vacuum being of sufficient magnitude to reduce evaporation of dopant from said interior doped layer of said tubular glass body, thereby effectively preventing a reduction in index of refraction in the center of the glass fiber.
Claim 17
Dependent Claim
15 words
The process of claim 14, wherein said the glass fiber has a circular cross section.
Claim 18
Dependent Claim
14 words
The process of claim 15, wherein said tubular glass body is precollapsed before drawing.
Claim 19
Dependent Claim
20 words
The process of claim 14, wherein said optical fiber exhibits a maximum refractive index at the center of the fiber.
Claim 20
Dependent Claim
28 words
The process of claim 14, wherein said dopant is selected from the group consisting of germanium dioxide, phosphorus pentoxide, and a mixture of germanium dioxide and phosphorus pentoxide.
Claim 21
Dependent Claim
20 words
The process of claim 18 wherein the optical fiber exhibits a maximum refractive index at the center of the fiber.
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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) | 1990-01-12 | 1990-07-14 | 1991-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-12 | 1994-07-14 | 1995-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-12 | 1998-07-14 | 1999-01-13 | $7700.00 | Window Closed / Lapsed |