Patent US4725112A successfully refreshed from Google Patents.
US4725112A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Buried undercut mesa-like waveguide
Assignee: Nokia Bell Labs
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Filing: 1985-08-06
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Granted: 1988-02-16
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Expires: 2005-08-06
Abstract
Abstract Epitaxial regrowth by vapor phase epitaxy of controlled composition semiconductor material in and around undercut regions of a processed heterostructure wafer permits formation of a ridge waveguide capable of active or passive operation. Subsequent material selective and crystallographically preferential etching is employed to form mirror facets on each end of the ridge waveguide.
Inventors
- 👤 Thomas J. Bridges
- 👤 Ernest G. Burkhardt
- 👤 Larry A. Coldren
- 👤 Thomas L. Koch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:55
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/20; H01S5/24; G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/13; G02B6/131; H01S5/2054; H01S5/2081; H01S5/22; H01S5/223; H01S5/2237; H01S5/227; H01S5/2275
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
122 words
A semiconductor waveguide device comprising a multilayered heterostructure comprising a first layer, a second layer, and third layer, said first and third layers having a wider energy bandgap than said second layer, said second layer formed on a first major surface of said first layer, said second layer measured parallel to the first major surface being less than the first and third layers measured in a corresponding direction to the second layer so that edges of the latter layers form an overhand region with respect to the edges of the second layer, the waveguide being characterized by a fourth layer of epitaxially grown semiconductor material completely filling in the overhang region and contacting the edges of the first, second and third layers.
Claim 2
Dependent Claim
122 words
A semiconductor waveguide device comprising a multilayered heterostructure comprising a first layer, a second layer, and third layer, said first and third layers having a wider energy bandgap than said second layer, said second layer formed on a first major surface of said first layer, said second layer measured parallel to the first major surface being less than the first and third layers measured in a corresponding direction to the second layer so that edges of the latter layers form an overhand region with respect to the edges of the second layer, the waveguide being characterized by a fourth layer of epitaxially grown semiconductor material completely filling in the overhang region and contacting the edges of the first, second and third layers.
Claim 3
Dependent Claim
19 words
The waveguide as defined in claim 1 wherein the fourth layer has a wider bandgap than the second layer.
Claim 4
Dependent Claim
15 words
The waveguide as defined in claim 2 wherein the fourth layer is an intrinsic semiconductor.
Claim 5
Dependent Claim
18 words
The waveguide as defined in claim 1 wherein the fourth layer is a doped semiconductor having high resistivity.
Claim 6
Dependent Claim
15 words
The waveguide as defined in claim 1 wherein the fourth layer is comprised of InP.
Claim 7
Dependent Claim
20 words
The waveguide as defined in claim 5 wherein the first, third and fourth layers comprise a substantially single crystal stoichiometry.
Claim 8
Dependent Claim
34 words
The waveguide as defined in claim 6 wherein the first, third, and fourth layers are etched in concentrated HCl to form an end mirror facet in a plane normal to the first major surface.
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) | 1991-02-15 | 1991-08-17 | 1992-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-15 | 1995-08-17 | 1996-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-15 | 1999-08-17 | 2000-02-16 | $7700.00 | Window Closed / Lapsed |