US4669816A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical waveguide coupler
Assignee: Nortel Networks Ltd
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Filing: 1984-11-28
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Granted: 1987-06-02
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Expires: 2004-11-28
Abstract
Abstract A single mode optical waveguide directional coupler is provided with enhanced wavelength selectivity by dividing the coupling region up into a number of identical sections (12) between which are interposed a set of identical decoupled sections (13) over which the two waveguides (10, 11) of the coupler are not optically coupled and have different optical path lengths.
Inventors
- 👤 George H. B. Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:57
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/293; G02B6/29331; G02B6/29332; G02B6/2804; G02B6/2821; G02B6/2826; G02B6/283
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
156 words
A wavelength selective optical waveguide coupler in which first and second single mode optical waveguides are provided with a set of identical coupling regions interspersed with a set of identical decoupled regions, wherein in each of the coupling regions the waveguides are dimensioned to provide matching propagation constants and extend alongside each other in sufficiently close proximity for their evanescent fields to overlap to the extent necessary to produce the required optical coupling, wherein in each of the decoupled regions the two waveguides have different optical path lengths, and wherein the aggregate length of the coupling regions is such that, for at least one wavelength for which the optical path difference of each of the intervening decoupled regions produces a relative phase shift between the two waveguides of an integral number of 2π radians, the coupling regions co-operate to provide a substantially complete transfer of optical power from either one of the waveguides to the other.
Claim 2
Dependent Claim
156 words
A wavelength selective optical waveguide coupler in which first and second single mode optical waveguides are provided with a set of identical coupling regions interspersed with a set of identical decoupled regions, wherein in each of the coupling regions the waveguides are dimensioned to provide matching propagation constants and extend alongside each other in sufficiently close proximity for their evanescent fields to overlap to the extent necessary to produce the required optical coupling, wherein in each of the decoupled regions the two waveguides have different optical path lengths, and wherein the aggregate length of the coupling regions is such that, for at least one wavelength for which the optical path difference of each of the intervening decoupled regions produces a relative phase shift between the two waveguides of an integral number of 2π radians, the coupling regions co-operate to provide a substantially complete transfer of optical power from either one of the waveguides to the other.
Claim 3
Dependent Claim
24 words
A coupler as claimed in claim 1, wherein in each of the decoupled regions the two waveguides are dimensioned to provide mismatched propagation constants.
Claim 4
Dependent Claim
13 words
A coupler as claimed in claim 2, wherein the waveguides are slab waveguides.
Claim 5
Dependent Claim
31 words
A coupler as claimed in claim 1, wherein in each of the decoupled regions the two waveguides are decoupled by virtue of the magnitude of the separation between their optical cores.
Claim 6
Dependent Claim
13 words
A coupler as claimed in claim 4, wherein the waveguides are fibre waveguides.
Claim 7
Dependent Claim
23 words
A coupler as claimed in claim 5, wherein the waveguides are wrapped in coils in opposite senses around two mandrels of different girth.
Claim 8
Dependent Claim
25 words
A coupler as claimed in claim 6, wherein each waveguide mandrel is provided with a flat facing a corresponding flat in the other waveguide mandrel.
Claim 9
Dependent Claim
17 words
A coupler as claimed in claim 6, wherein one of the waveguide mandrels is magnetostrictive or electrostrictive.
Claim 10
Dependent Claim
59 words
A coupler as claimed in claim 6, wherein each fibre waveguide is provided with an asymmetric arrangement of core and cladding and the fibres are disposed such that in the coupling regions the core of each fibre waveguide is closer to the outer surface of its cladding on the side facing the other fibre waveguide than on other sides.
Claim 11
Dependent Claim
17 words
A coupler as claimed in claim 9, wherein one of the waveguide mandrels is magnetostrictive or electrostrictive.
Claim 12
Dependent Claim
23 words
A coupler as claimed in claim 2, wherein the optical axes of the two waveguides have a substantially constant separation throughout the coupler.
Claim 13
Dependent Claim
21 words
A coupler as claimed in claim 11, wherein the optical axes of the two waveguides are substantially straight throughout the coupler.
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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) | 1990-06-01 | 1990-12-01 | 1991-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-01 | 1994-12-01 | 1995-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-01 | 1998-12-01 | 1999-06-02 | $7700.00 | Window Closed / Lapsed |