US4585491A
Expired / Lapsed
US
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Wavelength tuning of quantum well lasers by thermal annealing
Assignee: Xerox Corp
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Filing: 1983-09-02
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Granted: 1986-04-29
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Expires: 2003-09-02
Abstract
Abstract The method of tuning the wavelength of a quantum well laser to a shorter emission wavelength is accomplished by the step of thermal annealing the laser for a prescribed period of time, the length of the period and the temperature of annealing being based upon what primary emission wavelength is desired. For good results, the annealing is conducted in an elemental anti-outdiffusion environment or the laser structure to be annealed is encapsulated so that any outdiffusion of laser elemental constituents is discouraged during thermal annealing. In an exemplary illustration of the invention, laser heterostructures of the GaAl/GaAlAs regime are utilized and annealed for several hours in an As environment to selectively reduce the emission wavelength by as much as 200 ANGSTROM or more. The As environment prevents the outdiffusion of As from the GaAl/GaAlAs heterostructure during thermal annealing, elemental As having the lowest temperature of vaporization of elemental Ga, Al and As. High temperature annealing above this temperature may tend to drive elemental As from the heterostructure thereby changing its operating characteristics. Thermal annealing may be carried out in an annealing furnace, generally sealed in a quartz ampoule, or in a thermal pulse annealing system wherein properly prepared wafer samples may be alternately heated uniformly for prescribed periods of time at predetermined temperatures and periodically checked to determine the amount emission wavelength shift as compared to the set emission wavelength desired to be achieved for the laser.
Inventors
- 👤 Robert Burnham
- 👤 Nick Holonyak, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:32
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/819; H10H20/821; B; B82; B82Y; B82Y20/00; H01; H01S; H01S5/00; H01S5/30; H01S5/34; H01S5/343; H01S5/34313; H10H20/01; H10H20/011; H10H20/013; H01S5/3432; Y; Y10; Y10S; Y10S438/00; Y10S438/909
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
40 words
The method of tuning the emission wavelength of a quantum well laser structure to a shorter emission wavelength comprising the steps of thermal annealing said structure and monitoring the emission wavelength thereof until the desired primary emission wavelength is achieved.
Claim 2
Independent Claim
40 words
The method of tuning the emission wavelength of a quantum well laser structure to a shorter emission wavelength comprising the steps of thermal annealing said structure and monitoring the emission wavelength thereof until the desired primary emission wavelength is achieved.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein the step of annealing is conducted in an elemental anti-outdiffusion environment.
Claim 4
Dependent Claim
23 words
The method of claim 1 wherein the rate of annealing is varied by changing the period of annealing and/or the temperature of annealing.
Claim 5
Dependent Claim
16 words
The method of claim 1 wherein said thermal annealing is carried out in a heating furnace.
Claim 6
Dependent Claim
13 words
The method of claim 1 wherein said thermal annealing comprise thermal pulse annealing.
Claim 7
Dependent Claim
20 words
The method of claim 2 wherein the rate of annealing is varied by changing of the overpressure of said environment.
Claim 8
Dependent Claim
17 words
The method of claim 2 wherein said quantum well structure comprises GaAs/GaAlAs regime, said environment comprises As.
Claim 9
Dependent Claim
24 words
The method of claim 2 wherein said quantum well structure comprises GaAs/GaAlAs regime, said elemental anti-outdiffusion environment is air, nitrogen or an inert gas.
Claim 10
Dependent Claim
25 words
The method of claim 3 wherein the time period of annealing is decreased as the emission wavelength of the structure nears the desired emission wavelength.
Claim 11
Dependent Claim
16 words
The method of claim 7 wherein said quantum well structure comprise a single quantum well laser.
Claim 12
Dependent Claim
16 words
The method of claim 7 wherein said quantum well structure comprise a multiple quantum well laser.
Claim 13
Dependent Claim
25 words
The method of claim 5 wherein said thermal pulse annealing is accomplished by either a high temperature incoherent light source or a graphic strip heater.
Claim 14
Independent Claim
185 words
The method of tuning the emission wavelength of a quantum well laser structure to a set value for the emission wavelength comprising the steps of (1) heating the quantum well structure to a temperature sufficiently high to causally change the emission spectra of said laser structure due to interdiffusion changes at its quantum well(s) effectively changing the well energy levels thereof, (2) annealing the structure for a prescribed period of time at a predetermined temperature, (3) checking the emission spectra of the structure after termination of the annealing period to determine the primary emission wavelength of the structure, (4) comparing the determined value of the structure primary emission wavelength with the set value for the primary emission wavelength, (5) repetitively annealing the structure for said prescribed period of time at said predetermined temperature, checking the emission spectra of the structure after termination of each annealing period to determine the emission wavelength of the structure and comparing the determined value of the structure emission wavelength with the set value for the emission wavelength until the determine value approximates the set value for the primary emission wavelength.
Claim 15
Independent Claim
185 words
The method of tuning the emission wavelength of a quantum well laser structure to a set value for the emission wavelength comprising the steps of (1) heating the quantum well structure to a temperature sufficiently high to causally change the emission spectra of said laser structure due to interdiffusion changes at its quantum well(s) effectively changing the well energy levels thereof, (2) annealing the structure for a prescribed period of time at a predetermined temperature, (3) checking the emission spectra of the structure after termination of the annealing period to determine the primary emission wavelength of the structure, (4) comparing the determined value of the structure primary emission wavelength with the set value for the primary emission wavelength, (5) repetitively annealing the structure for said prescribed period of time at said predetermined temperature, checking the emission spectra of the structure after termination of each annealing period to determine the emission wavelength of the structure and comparing the determined value of the structure emission wavelength with the set value for the emission wavelength until the determine value approximates the set value for the primary emission wavelength.
Claim 16
Dependent Claim
17 words
The method of claim 13 wherein the step of annealing is conducted in an elemental anti-outdiffusion environment.
Claim 17
Dependent Claim
23 words
The method of claim 13 wherein the rate of annealing is varied by changing the period of annealing and/or the temperature of annealing.
Claim 18
Dependent Claim
15 words
The method of claim 13 wherein said annealing is carried out in a heating furnace.
Claim 19
Dependent Claim
12 words
The method of claim 13 wherein said annealing comprises thermal pulse annealing.
Claim 20
Dependent Claim
22 words
The method of claim 14 wherein the rate of annealing is varied by changing of the overpressure of said elemental anti-outdiffusion environment.
Claim 21
Dependent Claim
19 words
The method of claim 14 wherein said quantum well structure comprises GaAs/GaAlAs regime, said elemental anti-outdiffusion environment comprises As.
Claim 22
Dependent Claim
24 words
The method of claim 14 wherein said quantum well structure comprises GaAs/GaAlAs regime, said elemental anti-outdiffusion environment is air, nitrogen or an inert gas.
Claim 23
Dependent Claim
25 words
The method of claim 15 wherein the time period of annealing is decreased as the emission wavelength of the structure nears the desired emission wavelength.
Claim 24
Dependent Claim
15 words
The method of claim 19 wherein said quantum well structure comprises a single quantum laser.
Claim 25
Dependent Claim
16 words
The method of claim 19 wherein said quantum well structure comprises a multiple quantum well laser.
Claim 26
Dependent Claim
25 words
The method of claim 17 wherein said thermal pulse annealing is accomplished by either a high temperature incoherent light source as a graphic strip heater.
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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) | 1989-04-28 | 1989-10-28 | 1990-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-28 | 1993-10-28 | 1994-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-28 | 1997-10-28 | 1998-04-29 | $7700.00 | Window Closed / Lapsed |