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EP0136839A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Semiconductor lasers

Assignee: Xerox Corp
•
Filing: 1984-09-03
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Granted: —
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Expires: 2004-09-03
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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 20. 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 EP
Data Source google_patents
Last Synchronized 2026-11-02 00:24
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: 19
Claim 1
Independent Claim 34 words
The method of tuning the emission wavelength of a quantum well laster structure to a shorter emission wavelength comprising the step of thermal annealing said structure until the desired primary emission wavelength is achieved.
Claim 2
Independent Claim 34 words
The method of tuning the emission wavelength of a quantum well laster structure to a shorter emission wavelength comprising the step of thermal annealing said structure 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 21 words
The method of claim 2 wherein the rate of annealing is varied by changing the timer period and/or temperature of annealing.
Claim 5
Dependent Claim 25 words
The method of claim 3 wherein the timer period of annealing Is decreased as the emission wavelength of the structure nears the desired emission wavelength.
Claim 6
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 7
Dependent Claim 17 words
The method of claim 2 wherein said quantum well structure comprises GaAs/GaAIAs regime, said environment comprises As.
Claim 8
Dependent Claim 16 words
The method of claim 6 wherein said quantum well structure comprise a single quantum well laser.
Claim 9
Dependent Claim 16 words
The method of claim 6 wherein said quantum well structure comprise a multiple quantum well laser.
Claim 10
Dependent Claim 22 words
The method of claim 2 wherein said quantum well structure comprises GaAs/GaAlAs regime, said environment is air, nitrogen or an inert gas.
Claim 11
Dependent Claim 16 words
The method of claim 1 wherein said thermal annealing is carried out in a heating furnace.
Claim 12
Dependent Claim 13 words
The method of claim 1 wherein said thermal annealing comprise thermal pulse annealing.
Claim 13
Dependent Claim 25 words
The method of claim 11 wherein said thermal pulse annealing is accomplished by either a high temperature incoherent light source or a graphic strip heater.
Claim 14
Independent Claim 184 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 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 184 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 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 19 words
A quantum well laser structure with its primary emission wavelength tuned in accordance with the method of claim 13.
Claim 17
Dependent Claim 26 words
The quantum well laser structure of claim 13 wherein said structure comprises either a single quantum well heterostructure laser or a multiple quantum well heterostructure laser.
Claim 18
Dependent Claim 34 words
A quantum well laser structure with its primary emission wavelength tuned to a shorter emission wavelength by thermal annealing said structure for a period of time until the desired primary emission wavelength is achieved.
Claim 19
Dependent Claim 34 words
A quantum well laser structure with its primary emission wavelength tuned to a shorter emission wavelength by thermal annealing said structure for a period of time until the desired primary emission wavelength is achieved.

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