US4201447A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Termination for graded index fiber
Assignee: International Standard Electric Corp
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Filing: 1978-06-26
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Granted: 1980-05-06
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Expires: 1998-06-26
Abstract
Abstract A short length of step index fibre is placed in front of graded index fibre. Walls of the step index fibre form multiple images of its entrance face which are imaged by the graded index fibre to give a more nearly uniform illumination of the graded index fibre and thereby avoid the variable loss properties which can result from the repetitive focusing produced by point illumination or well collimated illumination.
Inventors
- 👤 George H. B. Thompson
- 👤 Peter R. Selway
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:18
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/42; G02B6/4201; G02B6/4204; G02B6/421; G02B6/241; G02B6/4202; G02B6/4203; G02B6/02; G02B6/028
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
97 words
A graded index optical fibre terminating in a coupling piece of step index fibre whose numerical aperture is matched with or greater than that wherein the cores of the abutting ends of said fibres have matching cross-sections, and wherein the length of the coupling piece of step index fibre is at least that at which the calculated lateral spacing of the first images in the graded index fibre of the remote end of the step index fibre is matched with or smaller than the maximum detail observable in the highest propagating mode of the step index fibre.
Claim 2
Dependent Claim
97 words
A graded index optical fibre terminating in a coupling piece of step index fibre whose numerical aperture is matched with or greater than that wherein the cores of the abutting ends of said fibres have matching cross-sections, and wherein the length of the coupling piece of step index fibre is at least that at which the calculated lateral spacing of the first images in the graded index fibre of the remote end of the step index fibre is matched with or smaller than the maximum detail observable in the highest propagating mode of the step index fibre.
Claim 3
Dependent Claim
25 words
An optical fibre as claimed in claim 1 wherein the length of the coupling piece of step index fibre is at least 2 cm long.
Claim 4
Dependent Claim
22 words
An optical fibre as claimed in claim 1 wherein the cross-section of the coupling piece of step index fibre is substantially rectangular.
Claim 5
Dependent Claim
21 words
An optical fibre as claimed in claim 1 wherein the cross-section of the coupling piece of step index fibre is circular.
Claim 6
Dependent Claim
18 words
An optical fibre as claimed in claim 1 wherein the coupling piece of step index fibre is tapered.
Claim 7
Dependent Claim
31 words
An optical fibre as claimed in claim 1 wherein the cross section of the coupling piece of step index fibre changes from elliptical at one end to circular at the other.
Claim 8
Independent Claim
124 words
A method of coupling a light source to a graded index fibre wherein a coupling length of step index fibre is inserted between the light source and the graded index fibre, wherein the abutting ends of said fibres have matching cross sections, wherein the numerical aperture of the step index fibre is matched with or greater than that of the light source, and wherein the length of the coupling piece of step index fibre is at least that at which the calculated lateral spacing of the first set of images in the graded index fibre of the remote end of the step index fibre is matched with or smaller than the maximum detail observable in the highest propagating mode of the step index fibre.
Claim 9
Independent Claim
124 words
A method of coupling a light source to a graded index fibre wherein a coupling length of step index fibre is inserted between the light source and the graded index fibre, wherein the abutting ends of said fibres have matching cross sections, wherein the numerical aperture of the step index fibre is matched with or greater than that of the light source, and wherein the length of the coupling piece of step index fibre is at least that at which the calculated lateral spacing of the first set of images in the graded index fibre of the remote end of the step index fibre is matched with or smaller than the maximum detail observable in the highest propagating mode of the step index fibre.
Claim 10
Dependent Claim
14 words
A method as claimed in claim 8 wherein the light source is a laser.
Claim 11
Dependent Claim
22 words
A method as claimed in claim 8 wherein the light source is the end of another optical fibre having light propagating therethrough.
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) | 1983-05-06 | 1983-11-05 | 1984-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-05-06 | 1987-11-05 | 1988-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-05-06 | 1991-11-05 | 1992-05-06 | $7700.00 | Window Closed / Lapsed |