US4586784A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modal-insensitive biconical taper couplers
Assignee: Canada Minister of Communications
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Filing: 1985-09-09
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Granted: 1986-05-06
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Expires: 2005-09-09
Abstract
Abstract The modal-insensitive coupler consists of a number N of optical multimode fiber lengths, each fiber length having a core of initial predetermined cross-sectional area. The fiber lengths are fused together in a coupling section such that the cores of the fiber lengths have a reduced cross-sectional area in the coupling section which supports a minimum number of modes of optical energy at a predetermined wavelength, and such that the fiber lengths have different core cross-sectional areas to produce preselected coupling ratios.
Inventors
- 👤 Yves Tremblay
- 👤 Brian S. Kawasaki
- 👤 Francois Bilodeau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:50
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/2804; G02B6/2821; G02B6/2835; G02B6/2856
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
131 words
A modal-insensitive coupler comprising a number N of optical multimode fiber lengths, each fiber length having a core of initial predetermined cross-sectional area, wherein the fiber lengths are fused and tapered together in a coupling section such that the cores of the fiber lengths have a reduced cross-sectional area in the coupling section for supporting a minimum number of modes of optical energy predetermined wavelength to obtain near complete core mode to cladding mode conversion and the ratio of the tapered core diameter to the initial core diameter of M of the fibers, where M<N, is smaller than the ratio of the tapered core diameter to the initial core diameter of the remaining N-M fibers, and such that the fiber lengths have predetermined core cross-sectional areas to produce preselected coupling ratios.
Claim 2
Dependent Claim
131 words
A modal-insensitive coupler comprising a number N of optical multimode fiber lengths, each fiber length having a core of initial predetermined cross-sectional area, wherein the fiber lengths are fused and tapered together in a coupling section such that the cores of the fiber lengths have a reduced cross-sectional area in the coupling section for supporting a minimum number of modes of optical energy predetermined wavelength to obtain near complete core mode to cladding mode conversion and the ratio of the tapered core diameter to the initial core diameter of M of the fibers, where M<N, is smaller than the ratio of the tapered core diameter to the initial core diameter of the remaining N-M fibers, and such that the fiber lengths have predetermined core cross-sectional areas to produce preselected coupling ratios.
Claim 3
Dependent Claim
10 words
A modal-insensitive coupler as claimed in claim 1 wherein M=N-1.
Claim 4
Dependent Claim
21 words
A modal-insensitive coupler as claimed in claim 1 or 2 whrein the initial cross-sectional areas of the fiber cores are identical.
Claim 5
Dependent Claim
12 words
A modal-insensitive coupler as claimed in claim 1 wherein N=2 and M=1.
Claim 6
Independent Claim
104 words
A method of producing a modal-insensitive coupler comprising: (a) selecting N optical multimode fiber lengths, each fiber length having a predetermined core cross-sectional area; (b) producing a biconical-taper region in M of the N fiber lengths, where M<N; (c) forming a bundle of the N fiber lengths with the biconical-taper regions being adjacent; (d) fusing the fibers along a section within the biconical-taper region; and (e) reducing the cross-sectional area of the fiber cores within the fused section such that a minimum number of modes of optical energy of predetermined wavelength can be supported to obtain near complete core mode to cladding mode conversion.
Claim 7
Independent Claim
104 words
A method of producing a modal-insensitive coupler comprising: (a) selecting N optical multimode fiber lengths, each fiber length having a predetermined core cross-sectional area; (b) producing a biconical-taper region in M of the N fiber lengths, where M<N; (c) forming a bundle of the N fiber lengths with the biconical-taper regions being adjacent; (d) fusing the fibers along a section within the biconical-taper region; and (e) reducing the cross-sectional area of the fiber cores within the fused section such that a minimum number of modes of optical energy of predetermined wavelength can be supported to obtain near complete core mode to cladding mode conversion.
Claim 8
Dependent Claim
18 words
A method as claimed in claim 5 wherein the cross-sectional areas of the selected fiber lengths are identical.
Claim 9
Dependent Claim
19 words
A method as claimed in claim 5 wherein the fusing step includes heating the fibers along the fused section.
Claim 10
Dependent Claim
14 words
A method as claimed in claim 5, 6, or 7 wherein N=2 and M=1.
Claim 11
Dependent Claim
12 words
A method as claimed in claim 5, 6 or 7 wherein M=N-1.
Claim 12
Dependent Claim
29 words
A method as claimed in claim 5 wherein the reducing step includes the placing of a tensile stress along the fused section while the fiber lengths are being heated.
Claim 13
Dependent Claim
11 words
A method as claimed in claim 10 wherein N=2 and M=1.
Claim 14
Dependent Claim
9 words
A method as claimed in claim 10 wherein M=N-1.
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) | 1989-05-05 | 1989-11-04 | 1990-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-05 | 1993-11-04 | 1994-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-05 | 1997-11-04 | 1998-05-06 | $7700.00 | Window Closed / Lapsed |