US4438446A
Expired / Lapsed
US
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Double barrier double heterostructure laser
Assignee: AT&T Inc
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Filing: 1981-05-29
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Granted: 1984-03-20
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Expires: 2001-05-29
Abstract
Abstract A double barrier double heterostructure laser is described in which relatively narrow beam divergence is obtained by the presence of wide bandgap, with respect to the cladding layers and barrier layers intermediate the active and cladding layers.
Inventors
- 👤 Won-Tien Tsang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:15
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/30; H01S5/32; H01S5/20; H01S5/2004; H01S5/2009; H01S5/3211
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
118 words
A light emitting device comprising an active layer having a first bandgap, first and second cladding layers having first and second conductivity types, respectively, and second and third bandgaps, respectively, said active layer being intermediate said first and second cladding layers, a first barrier layer intermediate said first cladding layer and active layer and having a first conductivity type, said first barrier layer having a fourth bandgap, and being directionally graded so that said fourth bandgap increases as the barrier layer-active layer interface is approached; said first bandgap being smaller than said second and third bandgaps and said fourth bandgap being greater than said second and third bandgaps; and electrical contacts to said first and second cladding layers.
Claim 2
Dependent Claim
118 words
A light emitting device comprising an active layer having a first bandgap, first and second cladding layers having first and second conductivity types, respectively, and second and third bandgaps, respectively, said active layer being intermediate said first and second cladding layers, a first barrier layer intermediate said first cladding layer and active layer and having a first conductivity type, said first barrier layer having a fourth bandgap, and being directionally graded so that said fourth bandgap increases as the barrier layer-active layer interface is approached; said first bandgap being smaller than said second and third bandgaps and said fourth bandgap being greater than said second and third bandgaps; and electrical contacts to said first and second cladding layers.
Claim 3
Dependent Claim
50 words
A device as recited in claim 1 further comprising a second barrier layer, said second barrier layer being intermediate said active layer and said second cladding layer and having a second conductivity type, said second barrier layer having a fifth bandgap which is greater than said second or third bandgaps.
Claim 4
Dependent Claim
16 words
A device as recited in claim 2 in which said second barrier layer is directionally graded.
Claim 5
Dependent Claim
33 words
A device as recited in claim 3 in which said at least one of the barrier layers has a bandgap greater than the bangaps of said cladding layers by at least 0.25 eV.
Claim 6
Dependent Claim
26 words
A device as recited in claim 2 in which said active layer comprises Al x Ga 1-x As with x equal to or less than 0.08.
Claim 7
Dependent Claim
27 words
A device as recited in claim 5 in which said cladding layers comprise Al x Ga 1-x As with x less than or equal to approximately 0.3.
Claim 8
Dependent Claim
38 words
A device as recited in claim 6 in which said barrier layers comprise Al v Ga 1-v As with v increasing from the value of x in the cladding layers to a value between approximately 0.45 and 0.70.
Claim 9
Dependent Claim
26 words
A device as recited in claim 7 in which said barrier layers have a thickness less than a wavelength of the radiation in the active layer.
Claim 10
Dependent Claim
21 words
A device as recited in claim 8 in which said barrier layers have a thickness between 250 Angstroms and 450 Angstroms.
Claim 11
Dependent Claim
28 words
A device as recited in claim 2 in which said first and second barrier layers have thicknesses less than a wavelength of the radiation in the active layer.
Claim 12
Dependent Claim
32 words
A device as recited in claim 10 in which at least one of said barrier layers has a bandgap greater than the bandgaps of said cladding layers by at least 0.25 eV.
References Cited (Backward Citations)
US4328469A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |