US4566754A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical fibres
Assignee: British Telecommunications PLC
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Filing: 1982-03-23
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Granted: 1986-01-28
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Expires: 2002-03-23
Abstract
Abstract An optical fibre capable of monomode transmission in, and having a wavelength of zero dispersion in, the 1.55 mu m window and having a core comprising silica and germanium dioxide and a cladding comprising silica is drawn from an appropriate preform at a temperature in the range from 1900 DEG C. to 2000 DEG C. Fibres thus produced have low loss compared with fibres drawn at higher temperature.
Inventors
- 👤 Keith J. Beales
- 👤 Clive R. Day
- 👤 Benjamin J. Ainslie
- 👤 James D. Rush
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:08
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/02; G02B6/02214; G02B6/02219; G02B6/02276; C; C03; C03B; C03B37/00; C03B37/01; C03B37/02; C03B37/022; C03B37/023; C03B37/025; C03B37/027; C03C; C03C13/00; C03C13/04; C03C13/045; C03B2201/00; C03B2201/02; C03B2201/06; C03B2201/30; C03B2201/31; C03B2203/00; C03B2203/10; C03B2203/22; C03B2203/24; C03B2203/36; Y; Y10; Y10S; Y10S65/00; Y10S65/15; Y10S65/16
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
145 words
In a method of producing an optical fibre having a core comprised of a silica-based glass having silica and germanium dioxide as the main constituents and a cladding comprised of a silica-based glass having silica as the main constituent, wherein the optical fibre is formed by drawing a preform at an elevated temperature, wherein the preform comprises a core portion and a cladding portion which correspond to the core and cladding of the formed optical fibre, and wherein the materials and dimensions of the core portion and cladding portion of the preform and the drawing ratio are such that the formed optical fibre is capable of monomode transmission in the 1.55 μm window and has a wavelength of zero dispersion in the 1.55 μm window, the improvement which comprises drawing the preform at a temperature in the range of from 1900° C. to 2000° C.
Claim 2
Dependent Claim
145 words
In a method of producing an optical fibre having a core comprised of a silica-based glass having silica and germanium dioxide as the main constituents and a cladding comprised of a silica-based glass having silica as the main constituent, wherein the optical fibre is formed by drawing a preform at an elevated temperature, wherein the preform comprises a core portion and a cladding portion which correspond to the core and cladding of the formed optical fibre, and wherein the materials and dimensions of the core portion and cladding portion of the preform and the drawing ratio are such that the formed optical fibre is capable of monomode transmission in the 1.55 μm window and has a wavelength of zero dispersion in the 1.55 μm window, the improvement which comprises drawing the preform at a temperature in the range of from 1900° C. to 2000° C.
Claim 3
Dependent Claim
19 words
A method according to claim 1, wherein the cladding has a refractive index close to that of pure silica.
Claim 4
Dependent Claim
13 words
A method according to claim 2, wherein the cladding contains phosphorus and fluorine.
Claim 5
Dependent Claim
29 words
A method according to claim 3, wherein the part of the cladding immediately adjacent to the core has lower phosphorus and fluorine concentrations than the remainder of the cladding.
Claim 6
Dependent Claim
14 words
A method according to claim 2, wherein the cladding consists entirely of pure silica.
Claim 7
Independent Claim
31 words
A method according to any of claims 2 to 4 and 1, wherein the concentration of germanium dioxide in the core is in the range from 6 to 11.5 mole percent.
Claim 8
Dependent Claim
17 words
A method according to claim 6, wherein the concentration of germanium dioxide is approximately 10 mole percent.
Claim 9
Independent Claim
32 words
A method according to any of claims 2 to 4 and 1, wherein the difference in refractive index between the core and the cladding is in the range from 0.009 to 0.016.
Claim 10
Dependent Claim
21 words
A method according to claim 8, wherein the difference in refractive index between the core and the cladding is approximately 0.012.
Claim 11
Dependent Claim
19 words
A method according to claim 1, wherein the core diameter is in the range from 4 to 5 μm.
Claim 12
Independent Claim
25 words
A method according to any of claims 2 to 4 and 1, wherein the drawing is performed at a speed of at least 20 meter/minute.
Claim 13
Dependent Claim
19 words
A method according to claim 11, wherein the speed is in the range from 20 meter/minute to 60 meter/minute.
Claim 14
Dependent Claim
19 words
A method according to claim 6, wherein the drawing is performed at a speed of at least 20 meter/minute.
Claim 15
Dependent Claim
15 words
A method according to claim 1, wherein the cladding diameter is at least 20 μm.
Claim 16
Dependent Claim
19 words
A method according to claim 14, wherein the cladding diameter is in the range from 20 to 50 μm.
Claim 17
Dependent Claim
17 words
A method according to claim 1, wherein the preform has been produced by modified chemical vapour deposition.
Claim 18
Dependent Claim
20 words
An optical fibre which has been produced by a method according to any of claims 2 to 4 and 1.
Claim 19
Dependent Claim
14 words
An optical fibre which has been produced by a method according to claim 6.
Claim 20
Dependent Claim
14 words
An optical fibre which has been produced by a method according to claim 11.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-01-27 | 1989-07-29 | 1990-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-27 | 1993-07-29 | 1994-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-27 | 1997-07-29 | 1998-01-28 | $7700.00 | Window Closed / Lapsed |