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Patent US5408487A successfully refreshed from Google Patents.
US5408487A
Expired / Lapsed
US
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Semiconductor laser
Assignee: Fujitsu Ltd
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Filing: 1994-03-17
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Granted: 1995-04-18
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Expires: 2014-03-17
Abstract
Abstract A group III-V compound semiconductor laser of a 1 μm band having an excellent conversion efficiency and a high characteristic temperature. The semiconductor laser can emit light in a 1.3 μm band or a 1.55 μm, and has a laser structure including an active layer For emitting light, guide layers sandwiching the active layer and having a band gap larger than the active layer, and clad layers embracing the guide layers and having a band gap larger than the guide layers. The lattice constants of the guide layers and clad layers are larger than a1 by 0.5% or more and smaller than a2 by 0.5% or more, where a1 represents the lattice constant of GaAs and a2 is the lattice constant of InP.
Inventors
- 👤 Toru Uchida
- 👤 Chikashi Anayama
- 👤 Susumu Yamazaki
- 👤 Hirohide Kurakake
- 👤 Akito Kuramata
- 👤 Haruhisa Soda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:58
CPC Classifications
B; B82; B82Y; B82Y20/00; H; H01; H01S; H01S5/00; H01S5/20; H01S5/22; H01S5/2201; H01S5/30; H01S5/32; H01S5/323; H01S5/34; H01S5/343; H01S5/34313; H01S2302/00; H01S5/02; H01S5/0206; H01S5/2004; H01S5/2009; H01S5/3201; H01S5/3211; H01S5/3218; H01S5/3403; H01S5/3406; H01S5/3415; H01S5/342; H01S5/34306
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
100 words
A group III-V compound semiconductor laser for emitting light, said semiconductor laser including: a laser structure including an active layer for emitting light, guide layers sandwiching the active layer and having a band gap larger than the active layer, and clad layers embracing the guide layers and having a band gap larger than the guide layers, wherein the lattice constants of said guide layers and said clad layers are larger than a1 by 0.5% or more and smaller than a2 by 0.5% or more, where a1 represents the lattice constant of GaAs and a2 is the lattice constant of InP.
Claim 2
Dependent Claim
100 words
A group III-V compound semiconductor laser for emitting light, said semiconductor laser including: a laser structure including an active layer for emitting light, guide layers sandwiching the active layer and having a band gap larger than the active layer, and clad layers embracing the guide layers and having a band gap larger than the guide layers, wherein the lattice constants of said guide layers and said clad layers are larger than a1 by 0.5% or more and smaller than a2 by 0.5% or more, where a1 represents the lattice constant of GaAs and a2 is the lattice constant of InP.
Claim 3
Dependent Claim
39 words
A group III-V compound semiconductor laser according to claim 1, said semiconductor laser emits light in a 1.3 μm band, and the lattice constants of said guide layer and clad layer are larger than a1 by 1.5% to 2.5%.
Claim 4
Dependent Claim
39 words
A group III-V compound semiconductor laser according to claim 1, said semiconductor laser emits light in a 1.55 μm band, and the lattice constants of said guide layer and clad layer are larger than a1 by 2.0% to 3.0%.
Claim 5
Dependent Claim
54 words
A group III-V compound semiconductor laser according to claim 1, further comprising an underlying crystalline layer having a lattice constant at the uppermost surface, said lattice constant being larger than a1 by 0.5% or more and smaller than a2 by 0.5% or more, wherein said laser structure is formed on said underlying crystalline layer.
Claim 6
Dependent Claim
28 words
A group III-V compound semiconductor laser according to claim 1, wherein said laser structure forms a cavity in which light reciprocally moves In the [1 1 0] direction.
Claim 7
Dependent Claim
29 words
A group III-V compound semiconductor laser according to claim 1, wherein said active layer of said laser structure has a lattice constant different from lattice constants of other layers.
Claim 8
Dependent Claim
39 words
A group III-V compound semiconductor laser according to claim 6, wherein the film thickness of said active layer of said laser structure is a film thickness of one mono-atomic layer or thicker and a critical film thickness or thinner.
Claim 9
Dependent Claim
52 words
A group III-V compound semiconductor laser according to claim 7, wherein said laser structure satisfies d2×{(a5-a6)/a6} 2 <9×10 -4 where d2 is a film thickness of said active layer, a5 is a lattice constant of said active layer at a no-strain state, and a6 is a lattice constant of said clad layer.
Claim 10
Dependent Claim
33 words
A group III-V compound semiconductor laser according to claim 6, wherein said active layer of said laser structure is made of InGaAs having a lattice constant larger than lattice constants of other layers.
Claim 11
Dependent Claim
38 words
A group III-V compound semiconductor laser according to claim 4, wherein said underlying crystalline layer includes a substrate and a group III-V compound semiconductor gradient composition layer whose composition is gradually changed from a composition lattice-matching said substrate.
Claim 12
Dependent Claim
70 words
A group III-V compound semiconductor laser according to claim 10, wherein said gradient composition layer satisfies |(a4-a3)/d1|<1.6×10 -5 where d1 is a film thickness of said gradient composition layer, a3 is a lattice constant of said gradient composition layer 2a at a no-strain state at the interface with said substrate, and a4 is a lattice constant of said gradient composition layer at a no-strain state at the uppermost surface thereof.
Claim 13
Dependent Claim
19 words
A group III-V compound semiconductor laser according to claim 11, wherein said gradient composition layer satisfies |(a4-a3)/d1|<1.2×10 -5 .
Claim 14
Dependent Claim
19 words
A group III-V compound semiconductor laser according to claim 12, wherein said gradient composition layer satisfies |(a4-a3)/d1|<1.2×10 -5 .
Claim 15
Dependent Claim
30 words
A group III-V compound semiconductor laser according to claim 10, wherein said underlying crystalline layer further includes a uniform composition layer grown on and lattice-matched with said gradient composition layer.
Claim 16
Dependent Claim
47 words
A group III-V compound semiconductor laser according to claim 14, wherein the lattice constant of said uniform composition layer is smaller by about 5% or larger by about 5% than the lattice constant of said gradient composition layer at a no-strain state at the uppermost surface thereof.
Claim 17
Dependent Claim
37 words
A group III-V compound semiconductor laser according to claim 10, wherein said gradient composition layer essentially consists of at least two kinds of aluminum, indium, and gallium and of at least one kind of arsenic and phosphorus.
Claim 18
Dependent Claim
37 words
A group III-V compound semiconductor laser according to claim 14, wherein said gradient composition layer essentially consists of at least two kinds of aluminum, indium, and gallium and of at least one kind of arsenic and phosphorus.
Claim 19
Dependent Claim
19 words
A group III-V compound semiconductor laser according to claim 10, wherein said gradient composition layer essentially consists of InGaAs.
Claim 20
Dependent Claim
19 words
A group III-V compound semiconductor laser according to claim 14, wherein said gradient composition layer essentially consists of InGaAs.
Claim 21
Dependent Claim
19 words
A group III-V compound semiconductor laser according to claim 10, wherein said substrate is made of GaAs or InP.
Claim 22
Dependent Claim
19 words
A group III-V compound semiconductor laser according to claim 14, wherein said substrate is made of GaAs or InP.
Claim 23
Dependent Claim
45 words
A group III-V compound semiconductor laser according to claim 14, wherein said substrate is made of GaAs, said gradient composition layer essentially consists of InGaAs and has a composition In x Ga 1-x As at the uppermost surface thereof where x is 0.2 to 0.35.
Claim 24
Dependent Claim
44 words
A group III-V compound semiconductor laser according to claim 1 wherein at least one of said clad layers is made of a material having a band gap wider than InGaAs having the same lattice constant as said at least one of said clad layers.
Claim 25
Dependent Claim
36 words
A group III-V compound semiconductor laser according to claim 23, wherein said clad layer essentially consists of at least two kinds of aluminum, indium, and gallium and of at least one kind of arsenic and phosphorus.
Claim 26
Dependent Claim
18 words
A group III-V compound semiconductor laser according to claim 24, wherein said clad layer contains an aluminum component.
Claim 27
Dependent Claim
32 words
A group III-V compound semiconductor laser according to claim 24, wherein said clad layer essentially consists of AlGaInAsP having a band gap wider than InGaP having the same lattice constant as AlGaInAsP.
Claim 28
Dependent Claim
38 words
A group III-V compound semiconductor laser according to claim 1, wherein said clad layer on the side of said underlying crystalline layer is doped with group VI chalcogen elements at 5×10 18 to 3×10 19 cm -3 .
Claim 29
Dependent Claim
17 words
A group III-V compound semiconductor laser according to claim 27, wherein said group VI element includes Se.
Claim 30
Dependent Claim
28 words
A group III-V compound semiconductor laser according to claim 1, wherein said active layer includes two or more layers of the same composition disposed in said guide layers.
Claim 31
Dependent Claim
34 words
A group III-V compound semiconductor laser according to claim 1, wherein said guide layer has a composition represented by InGaAsP and has a P molar fraction of 0.3 or less as group V element.
Claim 32
Dependent Claim
27 words
A group III-V compound semiconductor laser according to claim 1, wherein said guide layer has a superlattice structure made of layers thinner than a de Broglie wavelegth.
Claim 33
Dependent Claim
24 words
A group III-V compound semiconductor laser according to claim 31, wherein said superlattice structure has a mixed crystal composition substantially in a non-miscible region.
Claim 34
Dependent Claim
30 words
A group III-V compound semiconductor laser according to claim 1, wherein said active layer has a superlattice structure having a layer alternately laminating an InAs layer and a GaAs layer.
Claim 35
Dependent Claim
32 words
A group III-V compound semiconductor laser according to claim 33, wherein said superlattice structure has a layer alternately laminating a 0.7 to 1 InAs layer and a 0.7 to 1 GaAs layer.
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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) | 1998-04-17 | 1998-10-17 | 1999-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-04-17 | 2002-10-17 | 2003-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-04-17 | 2006-10-17 | 2007-04-18 | $7700.00 | Window Closed / Lapsed |