US4722092A
Expired / Lapsed
US
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GaInAsP/InP distributed feedback laser
Assignee: Massachusetts Institute of Technology
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Filing: 1985-01-30
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Granted: 1988-01-26
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Expires: 2005-01-30
Abstract
Abstract A distributed feedback (DFB) type laser and a method and apparatus for forming same wherein a quaternary semiconductor active lasing strip of material is buried between a substrate of binary compound of one type conductivity material and a mesa binary compound body of opposite type conductivity and a periodic grating structure is etched into the plateau of the mesa. In one embodiment, ohmic contacts are provided on either side of the grating structure and the mesa is undercut adjacent the active strip to partly isolate the ohmic contacts from the homojunction formed when the active strip is buried, preferably using a mass-transport process. In another embodiment, the ohmic contacts are formed on the top of a deeply etched grating structure. A buried layer double heterostructure (DH) laser is also described with DFB grating formed on the side walls GOVERNMENT SUPPORT The Government has rights in this invention pursuant to Contract No. F19628-85C-0002, awarded by the Department of the Air Force.
Inventors
- 👤 Zong-Long Liau
- 👤 Dale C. Flanders
- 👤 James N. Walpole
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:00
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/10; H01S5/18; H01S5/185; H01S5/187; H01S5/12; H01S5/1228; H01S5/20; H01S5/22; H01S5/227; H01S5/04; H01S5/042; H01S5/0425; H01S5/04254; H01S5/2275
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
135 words
A double heterostructure distributed feedback type laser comprising: (a) a first body of semiconductor material having a major surface and a first type conductivity; (b) a second body of semiconductor material having a conductivity opposite said first type conductivity and formed in the shape of a mesa with an external plateau surface and an adjacent surface opposite said plateau surface; (c) a strip of active semiconductor material of narrower bandgap than the bandgap of the first and second bodies and embedded between said first and second bodies; (d) a periodic structure formed in the plateau of the second body and extending in parallel proximity with the strip of active semiconductor material; and (e) at least one ohmic contact strip formed on said plateau adjacent the periodic structure; and (f) contact means on said first body.
Claim 2
Dependent Claim
135 words
A double heterostructure distributed feedback type laser comprising: (a) a first body of semiconductor material having a major surface and a first type conductivity; (b) a second body of semiconductor material having a conductivity opposite said first type conductivity and formed in the shape of a mesa with an external plateau surface and an adjacent surface opposite said plateau surface; (c) a strip of active semiconductor material of narrower bandgap than the bandgap of the first and second bodies and embedded between said first and second bodies; (d) a periodic structure formed in the plateau of the second body and extending in parallel proximity with the strip of active semiconductor material; and (e) at least one ohmic contact strip formed on said plateau adjacent the periodic structure; and (f) contact means on said first body.
Claim 3
Dependent Claim
22 words
The laser of claim 1 wherein a pair of ohmic contact strips are formed, one on each side of said periodic structure.
Claim 4
Dependent Claim
24 words
The laser of claim 2 wherein the second body is undercut adjacent the strip on each side underneath a portion of the contact strips.
Claim 5
Dependent Claim
29 words
The laser of claim 1 wherein the material of the first and second bodies is a binary compound and the material of the active strip is a quaternary semiconductor.
Claim 6
Dependent Claim
146 words
A distributed feedback type laser comprising: (a) a first body having a major surface and comprised of semiconductor material having a first type conductivity; (b) a second body in the shape of a mesa having a plateau surface and an underlying surface aligned with the major surface of the first body, said second body being comprised of semiconductive material of opposite conductivity to said first body material; (c) a strip of active semiconductor material formed between said first and second bodies and embedded therein adjacent an undercut portion between the first and second bodies; (d) a periodic structure for providing a distributed feedback network formed in the plateau surface of the second body adjacent the strip; (e) an ohmic contact strip formed on said plateau surface adjacent said periodic structure and at least partially overlying said undercut portion; and (f) contact means on said first body.
Claim 7
Dependent Claim
146 words
A distributed feedback type laser comprising: (a) a first body having a major surface and comprised of semiconductor material having a first type conductivity; (b) a second body in the shape of a mesa having a plateau surface and an underlying surface aligned with the major surface of the first body, said second body being comprised of semiconductive material of opposite conductivity to said first body material; (c) a strip of active semiconductor material formed between said first and second bodies and embedded therein adjacent an undercut portion between the first and second bodies; (d) a periodic structure for providing a distributed feedback network formed in the plateau surface of the second body adjacent the strip; (e) an ohmic contact strip formed on said plateau surface adjacent said periodic structure and at least partially overlying said undercut portion; and (f) contact means on said first body.
Claim 8
Dependent Claim
12 words
The laser of claim 5 wherein the semiconductor materials are III-V materials.
Claim 9
Dependent Claim
16 words
The laser of claim 5 wherein the wavelength of the laser is 2 microns or less.
Claim 10
Dependent Claim
25 words
The laser of claim 5 wherein the first body and second bodies are formed of a binary compound and the active material of quaternary material.
Claim 11
Dependent Claim
17 words
The laser of claim 8 wherein the active material is GaInAsP and the binary compound is InP.
Claim 12
Dependent Claim
148 words
A distributed feedback type laser comprising: (a) a first body of semiconductor material having a major surface and a first type conductivity; (b) a second body of semiconductor material of conductivity opposite said first type conductivity and having a major surface adjacent to the major surface of said first body and formed in the shape of a mesa with an external plateau surface; (c) a strip of active semiconductor material embedded between said two bodies and extending along the major surfaces; (d) a periodic structure formed in said plateau surface adjacent said strip; said structure comprising corrugations extending into said surface of sufficient depth such that light waves travelling along the region of the active layer interact with proximate portions of the corrugations but not the remote portions; (e) ohmic contact means formed on the remote portions of the corrugations; and (f) contact means on said first body.
Claim 13
Dependent Claim
148 words
A distributed feedback type laser comprising: (a) a first body of semiconductor material having a major surface and a first type conductivity; (b) a second body of semiconductor material of conductivity opposite said first type conductivity and having a major surface adjacent to the major surface of said first body and formed in the shape of a mesa with an external plateau surface; (c) a strip of active semiconductor material embedded between said two bodies and extending along the major surfaces; (d) a periodic structure formed in said plateau surface adjacent said strip; said structure comprising corrugations extending into said surface of sufficient depth such that light waves travelling along the region of the active layer interact with proximate portions of the corrugations but not the remote portions; (e) ohmic contact means formed on the remote portions of the corrugations; and (f) contact means on said first body.
Claim 14
Dependent Claim
52 words
The laser of claim 10 wherein the second body comprises a layer of binary compound material about 2.0 microns in thickness and the depth of the corrugations is about 1.0 microns and the ohmic contact means is comprised of metallic material formed on the corrugations to a depth of about 0.3 microns.
Claim 15
Dependent Claim
15 words
The laser of claim 11 wherein the ohmic contact means is formed by angle evaporation.
Claim 16
Dependent Claim
87 words
A distributed feedback laser comprising: (a) a first body of semiconductor material having a first type conductivity; (b) a second body of semiconductor material of opposite type conductivity to the first type; (c) a strip of active lasing material formed between and embedded in said first and second bodies, said strip having a pair of side walls extending between said bodies with a periodic structure formed on at least one side wall of said embedded strip; and (d) contact means formed on said first and second body.
Claim 17
Dependent Claim
87 words
A distributed feedback laser comprising: (a) a first body of semiconductor material having a first type conductivity; (b) a second body of semiconductor material of opposite type conductivity to the first type; (c) a strip of active lasing material formed between and embedded in said first and second bodies, said strip having a pair of side walls extending between said bodies with a periodic structure formed on at least one side wall of said embedded strip; and (d) contact means formed on said first and second body.
Claim 18
Dependent Claim
43 words
The laser of claim 13 wherein the periodic structure is formed by transferring the periodicity of a periodic structure formed on an external surface of the second body to at least one said side wall of said strip before the strip is embedded.
Claim 19
Dependent Claim
147 words
A surface emiting laser diode with distributed feedback comprising: (a) a first body of semiconductor material having a first type conductivity and a major surface; (b) a second body of semiconductor material of opposite type conductivity to the first type and a major surface; (c) a strip of active semiconductor material buried between the major surfaces of the first and second bodies; (d) a periodic structure formed in an external surface of the second body extending adjacent to said strip; (e) at least one mirror-like surface extending transversely from the external surface of the second body at a 45° angle to said surface and adjacent an edge of the strip to reflect light emitted from the edge of the strip in a plane normal to the major surfaces and out the major surface of the first body; and (f) contact means on said first and second bodies.
Claim 20
Dependent Claim
147 words
A surface emiting laser diode with distributed feedback comprising: (a) a first body of semiconductor material having a first type conductivity and a major surface; (b) a second body of semiconductor material of opposite type conductivity to the first type and a major surface; (c) a strip of active semiconductor material buried between the major surfaces of the first and second bodies; (d) a periodic structure formed in an external surface of the second body extending adjacent to said strip; (e) at least one mirror-like surface extending transversely from the external surface of the second body at a 45° angle to said surface and adjacent an edge of the strip to reflect light emitted from the edge of the strip in a plane normal to the major surfaces and out the major surface of the first body; and (f) contact means on said first and second bodies.
Claim 21
Dependent Claim
35 words
The diode of claim 15 wherein the mirror-like surfaces are formed by etching the first and second bodies in a crystallographic plane extending at a 45° angle to the external surface of the second body.
Claim 22
Dependent Claim
27 words
The diode of claim 15 wherein an anti-reflective coating is formed on the major surface of the first body at the exit location of the emitted light.
Claim 23
Dependent Claim
32 words
The diode of claim 15 wherein the first and second bodies are formed of a binary compound and the strip of quaternary material is selected from the III-V class of semiconductor materials.
Claim 24
Dependent Claim
16 words
The diode of claim 18 wherein the binary compound is InP and the quaternary is InGaAsP.
Claim 25
Dependent Claim
140 words
A double heterostructure distributed feedback type laser comprising: (a) a substrate of semiconductor material having a major surface and a first type conductivity; (b) a layer of semiconductor material having a conductivity opposite said first type conductivity and formed in the shape of a mesa with an external plateau surface and an underlying surface; (c) a strip of active semiconductor material of narrower bandgap than the bandgap of the semiconductor material of the substrate or the layer formed on said major surface of the substrate and embedded between said substrate and said layer; (d) a periodic structure formed in the plateau of the layer and extending in parallel proximity with the strip of active semiconductor material; and (e) first ohmic contact means formed on said plateau adjacent the periodic structure; and (f) second ohmic contact means formed on said substrate.
Claim 26
Dependent Claim
140 words
A double heterostructure distributed feedback type laser comprising: (a) a substrate of semiconductor material having a major surface and a first type conductivity; (b) a layer of semiconductor material having a conductivity opposite said first type conductivity and formed in the shape of a mesa with an external plateau surface and an underlying surface; (c) a strip of active semiconductor material of narrower bandgap than the bandgap of the semiconductor material of the substrate or the layer formed on said major surface of the substrate and embedded between said substrate and said layer; (d) a periodic structure formed in the plateau of the layer and extending in parallel proximity with the strip of active semiconductor material; and (e) first ohmic contact means formed on said plateau adjacent the periodic structure; and (f) second ohmic contact means formed on said substrate.
Claim 27
Dependent Claim
26 words
The laser of claim 20 wherein the first ohmic contact means comprises a pair of ohmic contact strips, one on each side of said periodic structure.
Claim 28
Dependent Claim
23 words
The laser of claim 21 wherein the layer is undercut adjacent the strip on each side underneath a portion of the contact strips.
Claim 29
Dependent Claim
27 words
The laser of claim 20 wherein the material of the substrate and layer is a binary compound and the material of the strip is a quaternary semiconductor.
Claim 30
Dependent Claim
143 words
A distributed feedback type laser comprising: (a) a substrate having a major surface and comprised of semiconductor material having a first type conductivity; (b) a layer formed on the substrate in the shape of a mesa having a plateau surface and an underlying surface aligned with the major surface of the substrate, said layer being comprised of semiconductive material of opposite conductivity to said substrate material; (c) a strip of active semiconductor material formed between said substrate and layer and embedded therein adjacent an undercut portion between the substrate and layer; (d) a periodic structure for providing a distributed feedback network formed in the plateau surface of the layer adjacent the strip; (e) an ohmic contact strip formed on said plateau surface adjacent said periodic structure and at least partially overlying said undercut portion; and (f) an ohmic contact formed on said substrate.
Claim 31
Dependent Claim
143 words
A distributed feedback type laser comprising: (a) a substrate having a major surface and comprised of semiconductor material having a first type conductivity; (b) a layer formed on the substrate in the shape of a mesa having a plateau surface and an underlying surface aligned with the major surface of the substrate, said layer being comprised of semiconductive material of opposite conductivity to said substrate material; (c) a strip of active semiconductor material formed between said substrate and layer and embedded therein adjacent an undercut portion between the substrate and layer; (d) a periodic structure for providing a distributed feedback network formed in the plateau surface of the layer adjacent the strip; (e) an ohmic contact strip formed on said plateau surface adjacent said periodic structure and at least partially overlying said undercut portion; and (f) an ohmic contact formed on said substrate.
Claim 32
Dependent Claim
12 words
The laser of claim 24 wherein the semiconductor materials are III-V materials.
Claim 33
Dependent Claim
16 words
The laser of claim 24 wherein the wavelength of the laser is 2 microns or less.
Claim 34
Dependent Claim
23 words
The laser of claim 24 wherein the substrate and layer are formed of a binary compound and the active material of quaternary material.
Claim 35
Dependent Claim
17 words
The laser of claim 27 wherein the active material is GaInAsP and the binary compound is InP.
Claim 36
Dependent Claim
141 words
A distributed feedback type laser comprising: (a) a substrate of semiconductor material having a major surface and a first type conductivity; (b) a layer of semiconductor material of conductivity opposite said first type conductivity and having a major surface adjacent to the major surface of said substrate and formed in the shape of a mesa with an external plateau surface; (c) a strip of active semiconductor material embedded between said substrate and layer extending along the major surfaces; (d) a periodic structure formed in said plateau surface adjacent said strip; said structure comprising corrugations extending into said surface of sufficient depth such that light waves travelling along the region of the active layer interact with proximate portions of the corrugations but not the remote portions; (e) ohmic contact means formed on the remote portions of the corrugations and on said substrate.
Claim 37
Dependent Claim
141 words
A distributed feedback type laser comprising: (a) a substrate of semiconductor material having a major surface and a first type conductivity; (b) a layer of semiconductor material of conductivity opposite said first type conductivity and having a major surface adjacent to the major surface of said substrate and formed in the shape of a mesa with an external plateau surface; (c) a strip of active semiconductor material embedded between said substrate and layer extending along the major surfaces; (d) a periodic structure formed in said plateau surface adjacent said strip; said structure comprising corrugations extending into said surface of sufficient depth such that light waves travelling along the region of the active layer interact with proximate portions of the corrugations but not the remote portions; (e) ohmic contact means formed on the remote portions of the corrugations and on said substrate.
Claim 38
Dependent Claim
56 words
The laser of claim 29 wherein the second body comprises a layer of binary compound material about 2.0 microns in thickness and the depth of the corrugations is about 1.0 microns and the ohmic contact means on the remote portions is comprised of metallic material formed on the corrugations to a depth of about 0.3 microns.
Claim 39
Dependent Claim
85 words
A distributed feedback laser comprising: (a) a substrate of semiconductor material having a first type conductivity; (b) a layer of semiconductor material of opposite type conductivity to the first type; (c) a strip of active lasing material formed between and embedded in said substrate and layer, said strip having a pair of side walls extending between said substrate and layer with a periodic structure formed on at least one side wall of said embedded strip; and (d) contact means formed on said substrate and layer.
Claim 40
Dependent Claim
85 words
A distributed feedback laser comprising: (a) a substrate of semiconductor material having a first type conductivity; (b) a layer of semiconductor material of opposite type conductivity to the first type; (c) a strip of active lasing material formed between and embedded in said substrate and layer, said strip having a pair of side walls extending between said substrate and layer with a periodic structure formed on at least one side wall of said embedded strip; and (d) contact means formed on said substrate and layer.
Claim 41
Dependent Claim
43 words
The laser of claim 31 wherein the periodic structure is formed by transferring the periodicity of a periodic structure formed on an external surface of the second body to at least one said side wall of said strip before the strip is embedded.
Claim 42
Dependent Claim
141 words
A surface emitting laser diode with distributed feedback comprising: (a) a substrate a semiconductor material having a first type conductivity and a major surface; (b) a layer of semiconductor material of opposite type conductivity to the first type and a major surface; (c) a strip of active semiconductor material buried between the major surfaces of the substrate and layer; (d) a periodic structure formed in an external surface of the layer extending adjacent to said strip; (e) at least one mirror-like surface extending transversely from the external surface of the layer at a 45° angle to said surface and adjacent an edge of the strip to reflect light emitted from the edge of the strip in a plane normal to the major surfaces and out the major surface of the substrate; and (f) contact means formed on said substrate and layer.
Claim 43
Dependent Claim
141 words
A surface emitting laser diode with distributed feedback comprising: (a) a substrate a semiconductor material having a first type conductivity and a major surface; (b) a layer of semiconductor material of opposite type conductivity to the first type and a major surface; (c) a strip of active semiconductor material buried between the major surfaces of the substrate and layer; (d) a periodic structure formed in an external surface of the layer extending adjacent to said strip; (e) at least one mirror-like surface extending transversely from the external surface of the layer at a 45° angle to said surface and adjacent an edge of the strip to reflect light emitted from the edge of the strip in a plane normal to the major surfaces and out the major surface of the substrate; and (f) contact means formed on said substrate and layer.
Claim 44
Dependent Claim
34 words
The diode of claim 33 wherein the mirror-like surfaces are formed by etching the substrate and layer in a crystallographic plane extending at a 45° angle to the external surface of the second body.
Claim 45
Dependent Claim
26 words
The diode of claim 33 wherein an anti-reflective coating is formed on the major surface of the substrate at the exit location of the emitted light.
Claim 46
Dependent Claim
31 words
The diode of claim 33 wherein the first and second bodies are formed of a binary compound and the strip of quaternary material selected from the III-V class of semiconductor materials.
Claim 47
Dependent Claim
16 words
The diode of claim 36 wherein the binary compound is InP and the quaternary is InGaAsP.
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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) | 1991-01-25 | 1991-07-27 | 1992-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-25 | 1995-07-27 | 1996-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-25 | 1999-07-27 | 2000-01-26 | $7700.00 | Window Closed / Lapsed |