US4410993A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser diode
Assignee: Siemens AG
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Filing: 1981-04-17
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Granted: 1983-10-18
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Expires: 2001-04-17
Abstract
Abstract A multi-layer laser diode structure comprised of a semiconductor material, for example, gallium-aluminum-arsenide, having varying amounts of a dopant, such as aluminum, in the respective layers, includes a cover layer which is transparent to laser radiation and provided for total reflection of radiation generated in a laser-active layer positioned below the cover layer and an additional layer positioned on top of the cover layer and supporting a contact on its exterior surface. The additional layer is composed of a semiconductor material having a band gap which is greater by at least 2 kT relative to that of the material forming the laser-active layer. The exterior surface of the additional layer is substantially specularly smooth for radiation generated in the laser-active layer. Non-destructive testing of quality factors decisive for a completed laser diode can occur with this type of construction.
Inventors
- 👤 Karl-Heinz Zschauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:38
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/20; H01S5/2004
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
140 words
In a laser diode comprised of a multi-layer structure having a cover layer (4) for total reflection of radiation generated in a laser-active layer (2), said cover layer (4) being composed of a material which is transparent to said generated radiation, said laser-active layer (2) being positioned below and in contact with said cover layer (4), and an additional layer (10) positioned on top of said cover layer (4) and supporting a contact (12) on an exterior surface (11) thereof, the improvement comprising wherein: said additional layer (10) is composed of a semiconductor material having a band gap which is greater by at least 2 kT relative to that of the material forming said laser-active layer (2); and said additional layer (10) having an exterior surface (11) which is substantially specularly smooth for radiation generated in said laser-active layer (2).
Claim 2
Dependent Claim
140 words
In a laser diode comprised of a multi-layer structure having a cover layer (4) for total reflection of radiation generated in a laser-active layer (2), said cover layer (4) being composed of a material which is transparent to said generated radiation, said laser-active layer (2) being positioned below and in contact with said cover layer (4), and an additional layer (10) positioned on top of said cover layer (4) and supporting a contact (12) on an exterior surface (11) thereof, the improvement comprising wherein: said additional layer (10) is composed of a semiconductor material having a band gap which is greater by at least 2 kT relative to that of the material forming said laser-active layer (2); and said additional layer (10) having an exterior surface (11) which is substantially specularly smooth for radiation generated in said laser-active layer (2).
Claim 3
Dependent Claim
36 words
In a laser diode as defined in claim 1 wherein said band gap of said semiconductor material forming said additional layer is at least 5 kT greater than that of the material forming said laser-active layer.
Claim 4
Dependent Claim
75 words
In a laser diode as defined in claim 1 wherein said laser-active layer is composed of a material having the formula: Ga.sub.1-x Al.sub.x As wherein x is a numeral greater than zero, and said additional layer is composed of a material having the formula: Ga.sub.1-x' Al.sub.x' As wherein x' is a numeral greater than 0.04 but smaller than the amount of aluminum in said cover layer located between said additional layer and said laser-active layer.
Claim 5
Dependent Claim
134 words
A multi-layer laser diode structure comprising, in combination, a substrate composed of gallium-aluminum-arsenide containing about 2 to 12 mol percent of aluminum therein; a first layer positioned directly on said substrate and being composed of gallium-aluminum-arsenide containing about 25 to 40 mol percent of aluminum therein; a laser-active layer positioned directly on said first layer and being composed of gallium-aluminum-arsenide containing about 6 to 8 mol percent of aluminum therein; a second layer positioned directly on said laser-active layer and being composed of gallium-aluminum-arsenide containing about 25 to 40 mol percent of aluminum therein; and an additional layer positioned directly on said second layer and being composed of gallium-aluminum arsenide containing about 10 to 12 mol percent of aluminum therein, with a contact being positioned directly on an exterior surface of said additional layer.
Claim 6
Dependent Claim
134 words
A multi-layer laser diode structure comprising, in combination, a substrate composed of gallium-aluminum-arsenide containing about 2 to 12 mol percent of aluminum therein; a first layer positioned directly on said substrate and being composed of gallium-aluminum-arsenide containing about 25 to 40 mol percent of aluminum therein; a laser-active layer positioned directly on said first layer and being composed of gallium-aluminum-arsenide containing about 6 to 8 mol percent of aluminum therein; a second layer positioned directly on said laser-active layer and being composed of gallium-aluminum-arsenide containing about 25 to 40 mol percent of aluminum therein; and an additional layer positioned directly on said second layer and being composed of gallium-aluminum arsenide containing about 10 to 12 mol percent of aluminum therein, with a contact being positioned directly on an exterior surface of said additional layer.
Claim 7
Dependent Claim
50 words
A multi-layer laser diode structure as defined in claim 4, wherein said first and second layers contain about 35 mol percent of aluminum therein, said laser-active layer contains about 8 mol percent of aluminum therein and said additional layer contains no more than about 12 mol percent of aluminum therein.
Claim 8
Dependent Claim
22 words
A multi-layer laser diode structure as defined in claim 5, wherein said additional layer contains about 10 mol percent of aluminum therein.
References Cited (Backward Citations)
US4220960A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-17 | 1987-04-18 | 1987-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-17 | 1991-04-18 | 1991-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-17 | 1995-04-18 | 1995-10-18 | $7700.00 | Window Closed / Lapsed |