US4461535A
Expired / Lapsed
US
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Wavelength filters
Assignee: AT&T Inc
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Filing: 1981-10-21
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Granted: 1984-07-24
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Expires: 2001-10-21
Abstract
Abstract By introducing an asymmetry in the effective refractive index profile of a waveguide, wave energy can be extracted from the waveguide by radiation at wavelengths greater than a critical wavelength, where the latter is a function of the effective index distribution. This technique is employed to develop a variety of optical wavelength filters.
Inventors
- 👤 Enrique A. J. Marcatili
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:27
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/42; G02B6/4201; G02B6/4246; G02B6/26; G02B6/28; G02B6/293; G02F; G02F1/00; G02F1/01; G02F1/011; H; H10; H10F; H10F77/00; H10F77/30; H10F77/306; H10F77/331; G02B6/29331
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
62 words
A wavelength filter comprising: a wavepath whose effective refractive index profile is a maximum along its longitudinal axis and decreases asymmetrically along a direction perpendicular to said axis said index profile defining a critical wavelength λ c ; and means for collecting signal wave energy radiated away from said longitudinal axis of said wavepath having a wavelength longer then λ c .
Claim 2
Dependent Claim
62 words
A wavelength filter comprising: a wavepath whose effective refractive index profile is a maximum along its longitudinal axis and decreases asymmetrically along a direction perpendicular to said axis said index profile defining a critical wavelength λ c ; and means for collecting signal wave energy radiated away from said longitudinal axis of said wavepath having a wavelength longer then λ c .
Claim 3
Dependent Claim
50 words
The filter according to claim 1 wherein said wavepath includes a center portion having an effective refractive index n(1+Δ 2 ) disposed between a first outer layer of material having an effective refractive index n(1-Δ 1 ) and a second outer layer of material having an effective refractive index n.
Claim 4
Dependent Claim
30 words
The filter according to claim 2 wherein the critical wavelength λ c is given by ##EQU7## where: a is the width of said center portion between said two outer layers.
Claim 5
Dependent Claim
25 words
The filter according to claim 2 wherein the effective refractive index of said second layer increases as a function of distance from said center portion.
Claim 6
Dependent Claim
36 words
The filter according to claim 2 including a third outer layer of material contiguous with said second layer; said third layer having a refractive index that is greater than the refractive index of said second layer.
Claim 7
Dependent Claim
36 words
The filter according to claim 5 wherein said center portion, said second outer layer and said third outer layer form a resonant cavity tuned to the wavelength of the wave energy radiated by said center portion.
Claim 8
Dependent Claim
12 words
The filter according to claim 2 wherein said center portion is curved.
Claim 9
Dependent Claim
21 words
The filter according to claim 1 wherein said wavepath comprises a center portion disposed between a metallic slab and the ambient.
Claim 10
Dependent Claim
86 words
The filter according to claim 1 wherein said wavepath comprises a slab of material having a refractive index n 1 , wherein there is embedded a first strip of material having a refractive index n 2 and a second strip of material having a refractive index n 3 , where n 2 >n 3 >n 1 ; said strips being contiguous and extending coextensively along said slab; and wherein said means for collecting signal wave energy radiated from said filter is located within said second strip.
Claim 11
Dependent Claim
63 words
The filter according to claim 1 comprising: a slab of material having a first region of thickness d 1 and a second region of thickness d 2 where d 1 >d 2 ; tuning means included at longitudinal intervals along said first region; and means disposed at the end of each of said intervals for collecting wave energy radiated from said first region.
Claim 12
Dependent Claim
20 words
The filter according to claim 10 wherein said tuning means comprises incremental changes on the width of said first region.
Claim 13
Dependent Claim
21 words
The filter according to claim 10 wherein said tuning means comprises means for applying an electric field across said first region.
Claim 14
Dependent Claim
92 words
The filter according to claim 10 wherein each of said collecting means is located in said second region at least a distance D from said first region given by ##EQU8## where n(1+Δ 2 ) is the effective refractive index of said first region; n is the effective refractive index of said second region; n(1-Δ 1 ) is the effective refractive index of a third region located agjacent to said first region and opposite said second region; and λ is the wavelength of the longest wavelength signal component guided along the respective intervals.
Claim 15
Dependent Claim
75 words
A wavelength filter comprising: a pair of parallel waveguiding strips embedded in a substrate of lower refractive index and separated by a region whose refractive index is intermediate that of sad strips and said substrate, and the effective refractive index profile within the plane including said strips defines a critical wavelength λ c above which signal energy is radiated out of one of said strips and into the other of said strips through said region.
Claim 16
Dependent Claim
75 words
A wavelength filter comprising: a pair of parallel waveguiding strips embedded in a substrate of lower refractive index and separated by a region whose refractive index is intermediate that of sad strips and said substrate, and the effective refractive index profile within the plane including said strips defines a critical wavelength λ c above which signal energy is radiated out of one of said strips and into the other of said strips through said region.
Claim 17
Dependent Claim
31 words
The filter according to claim 14 wherein the width of said one strip decreases in incremental steps at longitudinal intervals therealong so as to decrease the critical wavelength along successive intervals.
Claim 18
Dependent Claim
23 words
The filter according to claim 14 including tuning means disposed at longitudinal intervals along said strips for impressing electric fields across said strips.
Claim 19
Dependent Claim
34 words
The filter according to claim 14 including means, longitudinally disposed along said other strip, for deflecting out of said other strip wave energy radiated out of said one strip and into said other strip.
Claim 20
Dependent Claim
56 words
A wavelength filter comprising: a pair of parallel waveguiding strips embedded in a substrate of lower refractive index and separated by a region whose refractive index is intermediate that of said strips and said substrate, and the distance between said strips is equal to between two and ten times the width of one of said strips.
Claim 21
Dependent Claim
56 words
A wavelength filter comprising: a pair of parallel waveguiding strips embedded in a substrate of lower refractive index and separated by a region whose refractive index is intermediate that of said strips and said substrate, and the distance between said strips is equal to between two and ten times the width of one of said strips.
References Cited (Backward Citations)
US3896402A
Cited
JPS533252A
Cited
JPS547949A
Cited
US4146297A
Cited
JPS54110858A
Cited
US4243295A
Cited
US4273411A
Cited
US4390236A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-07-24 | 1988-01-23 | 1988-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-24 | 1992-01-23 | 1992-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-24 | 1996-01-23 | 1996-07-24 | $7700.00 | Window Closed / Lapsed |