Patent US4964134A successfully refreshed from Google Patents.
US4964134A
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Semiconductor laser structures
Assignee: IPG Photonics Corp
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Filing: 1988-02-18
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Granted: 1990-10-16
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Expires: 2008-02-18
Abstract
Abstract A laser structure with highly p-doped active material which has a particularly low linewidth enhancement factor α. Hence the emission linewidth of the laser structure is relatively small. The structure shows a particular relationship between the photon energy, the band gap energy and the conduction band quasi Fermi level of the active material which minimizes α, the valence band being degenerate. These conditions can be used to design low α laser structures. Such structures are of particular application to directly modulated lasers or absorption modulators and also find application in coherent optical detection.
Inventors
- 👤 Leslie D. Westbrook
- 👤 Michael J. Adams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:52
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/811; H10H20/812; B; B82; B82Y; B82Y20/00; H01; H01S; H01S5/00; H01S5/10; H01S5/11; H01S5/12; H01S5/1231; H01S5/30; H01S5/305; H01S5/34; H01S5/06; H01S5/0618; H01S5/20; H01S5/22; H01S5/223; H01S5/3054; H01S5/32; H01S5/3202; H01S5/3428; H01S5/343; H01S5/34306; H01S5/34313
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
85 words
A direct band gap semiconductor laser structure having a resonant cavity and electrodes whose emission wavelength is less than its active material band gap equivalent wavelength by an amount such that the emitted photon energy is at least approximately equal to the sum of the band gap energy and the conduction band quasi Fermi level measured from the conduction band edge, the active material of the laser structure being doped p-type to a level at which the laser structure shows positive gain under working conditions.
Claim 2
Dependent Claim
85 words
A direct band gap semiconductor laser structure having a resonant cavity and electrodes whose emission wavelength is less than its active material band gap equivalent wavelength by an amount such that the emitted photon energy is at least approximately equal to the sum of the band gap energy and the conduction band quasi Fermi level measured from the conduction band edge, the active material of the laser structure being doped p-type to a level at which the laser structure shows positive gain under working conditions.
Claim 3
Dependent Claim
120 words
A direct band gap semiconductor laser structure having a resonant cavity and electrodes having means for determining its emission wavelength, wherein the following relationships are satisfied: (i) E is equal or approximately equal to ##EQU18## (ii) -Efv>McEfc/Mv where E is the emitted photon energy Eg is the band gap energy Mc is the conduction band electron effective mass Mv is the valence band hole effective mass Mr is the reduced mass given by the relationship 1/Mr=1/Mc+1/Mv Efc is the conduction band quasi Fermi level measured from the conduction band edge, and Efv is the valence band quasi Fermi level measured from the valence band edge, the material-dependent parameters of the above relating to the active material of the laser structure.
Claim 4
Dependent Claim
120 words
A direct band gap semiconductor laser structure having a resonant cavity and electrodes having means for determining its emission wavelength, wherein the following relationships are satisfied: (i) E is equal or approximately equal to ##EQU18## (ii) -Efv>McEfc/Mv where E is the emitted photon energy Eg is the band gap energy Mc is the conduction band electron effective mass Mv is the valence band hole effective mass Mr is the reduced mass given by the relationship 1/Mr=1/Mc+1/Mv Efc is the conduction band quasi Fermi level measured from the conduction band edge, and Efv is the valence band quasi Fermi level measured from the valence band edge, the material-dependent parameters of the above relating to the active material of the laser structure.
Claim 5
Dependent Claim
20 words
A laser structure according to claim 1 or 2 wherein the semiconductor laser structure comprises a quantum well active layer.
Claim 6
Dependent Claim
18 words
A laser structure according to claim 3 wherein the semiconductor laser structure comprises multiple quantum well active layers.
Claim 7
Dependent Claim
33 words
A laser structure according to claim 3 wherein the material of the active layer or layers is doped p-type to a level at least of the order of 4×10 18 cm -3 .
Claim 8
Dependent Claim
23 words
A laser structure according to either one of claims 1 or 2 wherein the semiconductor laser structure comprises a bulk semiconductor laser structure.
Claim 9
Dependent Claim
31 words
A laser structure according to claim 6 wherein the material of the active layer is doped p-type to a level at least of the order of 8×10 18 cm -3 .
Claim 10
Dependent Claim
21 words
A laser structure according to claim 1 or 2 wherein the active material of the laser structure comprises III-V semiconductor material.
Claim 11
Dependent Claim
17 words
A laser structure according to claim 8 wherein the active material of the laser structure comprises InGaAsP.
Claim 12
Dependent Claim
17 words
A laser structure according to claim 8 wherein the active material of the laser structure comprises InGaAs.
Claim 13
Dependent Claim
24 words
A laser structure according to claim 1 or 2 wherein the active material of the laser structure is doped p-type using the dopant berillium.
References Cited (Backward Citations)
US4257011A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-10-15 | 1994-04-16 | 1994-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-15 | 1998-04-16 | 1998-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-15 | 2002-04-16 | 2002-10-16 | $7700.00 | Window Closed / Lapsed |