US4923264A
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Resonance coupled optical coupler with semiconductor waveguide layer comprising a multi-quantum-well structure
Assignee: University of Pittsburgh
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Filing: 1989-01-18
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Granted: 1990-05-08
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Expires: 2009-01-18
Abstract
Abstract An electro-optic coupler made of consecutively deposited layers of semiconductor material has an one waveguide layer a multiple-quantum-well structure which exhibits a strong index of refraction dispersion in response to an electric field. Another waveguide layer separated from the multiple-quantum-well structure by a coupling layer is made of a bulk semiconductor material having an index of refraction which is comparatively unaffected by the electric field and which is substantially equal to one of the values of the index of refraction that the quantum well structure can assume. Resonant coupling of the waveguide layers is affected by a uniform electric field generated by a voltage applied between metalization on a confinement layer covering the top waveguide and a substrate on which the waveguide layers and coupling layer are grown over a lower confinement layer. When the indices of refraction of the two waveguides are equal, light injected into one waveguide is switched to the other. On the other hand, when the indices of refraction of the two waveguides are not equal, a parallel propagation condition exists. The coupler can be used either as a switch or an attenuator.
Inventors
- 👤 Dietrich W. Langer
- 👤 Marek Chmielowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:49
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/29; G02F1/31; G02F1/313; G02F1/3132; G02F1/3133; B; B82; B82Y; B82Y20/00; G02F1/01; G02F1/015; G02F1/017; G02F1/01708; G02F1/3135; G02F2202/00; G02F2202/10; G02F2202/101; G02F2202/102
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
174 words
An electro-optic coupler comprising a plurality of layers of semiconductor materials including: a first waveguide layer having an index of refraction n 1 ; a second waveguide layer comprising a multiple-quantum-well structure and having an index of refraction n 2 ; a coupling layer between said first and second waveguide layers having an index of refraction N; confinement layers outside said first and second waveguide layers and having an index of refraction n 3 ; and means for applying an electric field across said layers of semiconductor materials with n 1 , N and n 3 relative to n 2 being unaffected by said electric field, while n 2 varies substantially with the electric field from a first value in the absence of an electric field to a second value in the presence of said electric field, one of said first and second values of n 2 being essentially equal to n 1 , and n 3 being substantially less than n 1 and both the first and second values of n 2 .
Claim 2
Dependent Claim
174 words
An electro-optic coupler comprising a plurality of layers of semiconductor materials including: a first waveguide layer having an index of refraction n 1 ; a second waveguide layer comprising a multiple-quantum-well structure and having an index of refraction n 2 ; a coupling layer between said first and second waveguide layers having an index of refraction N; confinement layers outside said first and second waveguide layers and having an index of refraction n 3 ; and means for applying an electric field across said layers of semiconductor materials with n 1 , N and n 3 relative to n 2 being unaffected by said electric field, while n 2 varies substantially with the electric field from a first value in the absence of an electric field to a second value in the presence of said electric field, one of said first and second values of n 2 being essentially equal to n 1 , and n 3 being substantially less than n 1 and both the first and second values of n 2 .
Claim 3
Dependent Claim
67 words
The electro-optic coupler of claim 1 wherein said second waveguide layer extends a distance L in the direction of propagation of light injected into one of said first and second waveguide layers, wherein said first waveguide layer extends at least the distance L, and wherein L is selected to effect maximum coupling of light between said waveguide layers when n 1 and n 2 are substantially equal.
Claim 4
Dependent Claim
71 words
The electro-optic coupler of claim 2 wherein said layers of semiconductor materials are grown on a substrate doped to be a conductor, and wherein said means for applying said electric field includes an electrically conductive contact layer substantially coextensive with said second waveguide layer and spaced from the substrate by at least said second waveguide layer, and means applying said electric field between said electrically conductive contact layer and said substrate.
Claim 5
Dependent Claim
78 words
The electro-optic coupler of claim 2 wherein said layers of semiconductor materials are grown on an insulating substrate, and wherein said means for applying an electric field includes a first electrically conductive contact layer substantially coextensive with said second waveguide layer and spaced from the substrate by at least said second waveguide layer, a second electrically conductive contact layer applied to said substrate, and means applying said electric field between said first and second electrically conductive contact layers.
Claim 6
Dependent Claim
54 words
The electro-optic coupler of claim 2 wherein said means applying an electric field includes a first electrically conductive contact layer applied to one of said confinement layers, a second electrically conductive contact layer applied to the other confinement layer, and means applying said electric field between said first and second electrically conductive contact layers.
Claim 7
Dependent Claim
45 words
The electro-optic coupler of claim 2 wherein said one value of n 2 is said second value such that light injected into said one waveguide layer is switched to the other waveguide layer when said electric field is applied to said layers of semiconductor materials.
Claim 8
Dependent Claim
36 words
The electro-optic coupler of claim 2 wherein said second waveguide layer is grown over said first waveguide layer with a coupling layer in between, and wherein said second waveguide layer is etched to said length L.
Claim 9
Dependent Claim
36 words
The electro-optical coupler of claim 1 wherein said means for applying said electric field across said layers of semiconductor materials comprises means to apply a uniform electric field over coextensive areas of said wave guide layers.
Claim 10
Dependent Claim
37 words
The electro-optic coupler of claim 1 wherein said second waveguide layer comprises a plurality of quantum-well layers bounded by barrier layers with said quantum-well and barrier layers each having a thickness of about 5 to 20 nm.
Claim 11
Dependent Claim
22 words
The electro-optic coupler of claim 9 wherein said quantum well layers and barrier layers each have a thickness of about 10 nm.
Claim 12
Dependent Claim
17 words
The electro-optic coupler of claim 9 wherein said coupling layer is not thicker than about 1 μm.
Claim 13
Dependent Claim
17 words
The electro-optic coupler of claim 11 wherein said coupling layer is not thicker than about 0.5 μm.
Claim 14
Dependent Claim
15 words
The electro-optic coupler of claim 2 wherein said waveguide layers are about 1 μm thick.
Claim 15
Dependent Claim
18 words
The electro-optic coupler of claim 13 wherein said coupling layer is not more than about 0.5 μm thick.
Claim 16
Dependent Claim
16 words
The electro-optic coupler of claim 14 wherein said length L is less than about 120 μm.
Claim 17
Dependent Claim
37 words
The electric-optic coupler of claim 15 wherein said second waveguide layer comprises a plurality of quantum-well layers bound by barrier layers with said quantum-well and barrier layers each having a thickness of about 5 to 20 nm.
Claim 18
Dependent Claim
22 words
The electro-optic coupler of claim 15 wherein said quantum well layers and barrier layers each have a thickness of about 10 nm.
Claim 19
Dependent Claim
21 words
The electro-optic coupler of claim 1 wherein said semiconductor materials are selected from a group consisting of group III-group V compounds.
Claim 20
Dependent Claim
46 words
The electro-optic coupler of claim 18 wherein said first waveguide layers, said coupling layer and said confinement layers are made of AlGaAs compounds and wherein the multiple-quantum-well material of said second waveguide layer comprises quantum-well layers of GaAs bounded by barrier layers of an AlGaAs compound.
Claim 21
Dependent Claim
21 words
The electro-optic coupler of claim 1 wherein said semiconductor materials are selected from a group consisting of group II-group VI compounds.
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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) | 1993-05-07 | 1993-11-06 | 1994-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-07 | 1997-11-06 | 1998-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-07 | 2001-11-06 | 2002-05-08 | $7700.00 | Window Closed / Lapsed |