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US4307296A
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Method of observing the core region of optical fibers and preforms
Assignee: AT&T Inc
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Filing: 1980-04-14
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Granted: 1981-12-22
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Expires: 2000-04-14
Abstract
Abstract A method of observing the core region of optical fibers and fiber preforms is disclosed comprising the step of inducing fluorescence in at least one of the index-modifying dopants present in the core being observed by illuminating said fiber/preform with radiation at the peak absorption wavelength for said dopant, and observing the region between the fluorescing edges of said fiber/preform. The core diameter can be determined by measuring the distance between said edges. This technique can be utilized to control the fiber pulling rate during fabrication.
Inventors
- 👤 Herman M. Presby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:10
CPC Classifications
C; C03; C03B; C03B37/00; C03B37/01; C03B37/02; C03B37/03; C03B37/032; C03B37/025; C03B37/0253; G; G01; G01B; G01B11/00; G01B11/08; G01B11/10; G01B11/105; C03B2205/00; C03B2205/40
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
46 words
A method of outlining the core region of optical fibers and fiber preforms comprising the step of: inducing fluorescence in at least one of the index-modifying dopants present in the core (11) by illuminating said fiber/preform with radiation at the peak absorption wavelength from said dopant.
Claim 2
Independent Claim
46 words
A method of outlining the core region of optical fibers and fiber preforms comprising the step of: inducing fluorescence in at least one of the index-modifying dopants present in the core (11) by illuminating said fiber/preform with radiation at the peak absorption wavelength from said dopant.
Claim 3
Dependent Claim
18 words
The method according to claim 1 wherein said dopant is germanium, and said illuminating wavelength is 2500 Angstroms.
Claim 4
Dependent Claim
19 words
The method according to claim 1 wherein said illumination is directed at said fiber/preform along two, mutually perpendicular directions.
Claim 5
Dependent Claim
17 words
The method according to claim 1 including the further step of determining the diameter of said core.
Claim 6
Independent Claim
93 words
The method of pulling a fiber from a fiber preform including the steps of: pulling said fiber from said preform at an adjustable rate; illuminating said fiber as it is drawn with radiation at the peak absorption wavelength for at least one of the index-modifying dopant present in the fiber core; determining the diameter of the core region of said fiber by measuring the distance between the fluorescing edges of said fiber; comparing the measured diameter with a predetermined desired core diameter; and adjusting the fiber pulling rate in response to said comparison.
Claim 7
Independent Claim
93 words
The method of pulling a fiber from a fiber preform including the steps of: pulling said fiber from said preform at an adjustable rate; illuminating said fiber as it is drawn with radiation at the peak absorption wavelength for at least one of the index-modifying dopant present in the fiber core; determining the diameter of the core region of said fiber by measuring the distance between the fluorescing edges of said fiber; comparing the measured diameter with a predetermined desired core diameter; and adjusting the fiber pulling rate in response to said comparison.
References Cited (Backward Citations)
US3879128A
Cited
US4161656A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-12-21 | 1985-06-22 | 1985-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-21 | 1989-06-22 | 1989-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-21 | 1993-06-22 | 1993-12-22 | $7700.00 | Window Closed / Lapsed |