Author: Timothy James Drummond
Publisher:
ISBN:
Category :
Languages : en
Pages : 58
Book Description
Today there exists a need to be able to process increasing amounts of data at rates beyond the capabilities of existing purely electrical networks. To meet this need, networks which transmit data via an optical carrier rather than an electrical one are being developed. A necessary component of an optical network is a small, easily modulated source of coherent light. The only such source available is a laser diode. The first laser diode to operate continuously at room temperature was a double heterostructure (DH) (Al, Ga)As/GaAs laser prepared by liquid phase epitaxy (LPE). Much effort was subsequently devoted to reproducing those results by molecular beam epitaxy (MBE). MBE offers several advantages over LPE, such as control of composition and impurity profiles to atomic dimensions. Layers cna be grown on larger substrates and with a high degree of uniformity and reproducibility that is not possible with LPE. Despite these advantages, it was six years after the first continuous room temperature operation of an (Al, Ga)As/GaAs DH laser that a similar laser prepared by MBE was reported. The first MBE lasers typically had threshold current densities, Jth, about twice as large as similarly designed LPE lasers. Another three years passed before the art of MBE advanced to the point where it became possible to achieve laser performance equal to the LPE lasers. The presence of non-radiative recombination centers in the bulk (Al, Ga)As layers was shown to make a significant contribution to the high threshold current densities in MBE lasers.
The Fabrication of Double Heterostructure Aluminum Gallium Arsenide/gallium Arsenide Lasers by Molecular Beam Epitaxy
Author: Timothy James Drummond
Publisher:
ISBN:
Category :
Languages : en
Pages : 58
Book Description
Today there exists a need to be able to process increasing amounts of data at rates beyond the capabilities of existing purely electrical networks. To meet this need, networks which transmit data via an optical carrier rather than an electrical one are being developed. A necessary component of an optical network is a small, easily modulated source of coherent light. The only such source available is a laser diode. The first laser diode to operate continuously at room temperature was a double heterostructure (DH) (Al, Ga)As/GaAs laser prepared by liquid phase epitaxy (LPE). Much effort was subsequently devoted to reproducing those results by molecular beam epitaxy (MBE). MBE offers several advantages over LPE, such as control of composition and impurity profiles to atomic dimensions. Layers cna be grown on larger substrates and with a high degree of uniformity and reproducibility that is not possible with LPE. Despite these advantages, it was six years after the first continuous room temperature operation of an (Al, Ga)As/GaAs DH laser that a similar laser prepared by MBE was reported. The first MBE lasers typically had threshold current densities, Jth, about twice as large as similarly designed LPE lasers. Another three years passed before the art of MBE advanced to the point where it became possible to achieve laser performance equal to the LPE lasers. The presence of non-radiative recombination centers in the bulk (Al, Ga)As layers was shown to make a significant contribution to the high threshold current densities in MBE lasers.
Publisher:
ISBN:
Category :
Languages : en
Pages : 58
Book Description
Today there exists a need to be able to process increasing amounts of data at rates beyond the capabilities of existing purely electrical networks. To meet this need, networks which transmit data via an optical carrier rather than an electrical one are being developed. A necessary component of an optical network is a small, easily modulated source of coherent light. The only such source available is a laser diode. The first laser diode to operate continuously at room temperature was a double heterostructure (DH) (Al, Ga)As/GaAs laser prepared by liquid phase epitaxy (LPE). Much effort was subsequently devoted to reproducing those results by molecular beam epitaxy (MBE). MBE offers several advantages over LPE, such as control of composition and impurity profiles to atomic dimensions. Layers cna be grown on larger substrates and with a high degree of uniformity and reproducibility that is not possible with LPE. Despite these advantages, it was six years after the first continuous room temperature operation of an (Al, Ga)As/GaAs DH laser that a similar laser prepared by MBE was reported. The first MBE lasers typically had threshold current densities, Jth, about twice as large as similarly designed LPE lasers. Another three years passed before the art of MBE advanced to the point where it became possible to achieve laser performance equal to the LPE lasers. The presence of non-radiative recombination centers in the bulk (Al, Ga)As layers was shown to make a significant contribution to the high threshold current densities in MBE lasers.
Manufacturability of Gallium Arsenide/aluminum Gallium Arsenide Lasers Grown by Molecular Beam Epitaxy
Author: Sridhar V. Iyer
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The performance of high-power graded index separate confinement heterostructure single quantum well lasers grown by molecular beam epitaxy depends primarily on the quality of $Alsb{x}Gasb{1-x}As$ layers, the interface roughness, and the control of residual oxygen incorporation into the active region. Based on MBE growth experiments, a model for the incorporation, desorption and accumulation of oxygen during epitaxial growth of optical quality AlGaAs layers is proposed and validated. Based on this model, an optimal growth scheme for MBE grown GaAs/AlGaAs lasers is demonstrated. Over the growth of approximately one hundred and fifty lasers in a concurrent research, development, and manufacturing environment, the reduction of residual oxygen incorporation in GRINSCH-SQW lasers was found to be in excellent correlation with lower threshold density, higher quantum well photoluminesence intensity, and secondary ion mass spectroscopy data. The high growth temperatures required to prevent oxygen incorporation in the quantum well result in additional technical obstacles stymieing full exploitation of the growth technology for use in the manufacture of integrated opto-electronic circuits and systems. The inherent difficulties in accurately measuring growth temperature in MBE systems and the gallium desorption during high temperature growth can lead to nonuniformities in cladding material composition. These nonuniformities can lead to an asymmetrical waveguiding structure with distorted optical output characteristics. Distortions in the radiated optical pattern can greatly affect the alignment and coupling efficiency between laser diodes and optical fibers or other electro-optical systems in integrated opto-electronic applications. A two-dimensional dielectric waveguide simulator has been used to analyze the optical properties of GRINSCH GaAs/AlGaAs lasers with asymmetrical cladding structures induced by noise in growth temperature measurement. Through this analysis, an optimal device structure which has the desired optical characteristics and is less sensitive to cladding composition asymmetries is demonstrated.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The performance of high-power graded index separate confinement heterostructure single quantum well lasers grown by molecular beam epitaxy depends primarily on the quality of $Alsb{x}Gasb{1-x}As$ layers, the interface roughness, and the control of residual oxygen incorporation into the active region. Based on MBE growth experiments, a model for the incorporation, desorption and accumulation of oxygen during epitaxial growth of optical quality AlGaAs layers is proposed and validated. Based on this model, an optimal growth scheme for MBE grown GaAs/AlGaAs lasers is demonstrated. Over the growth of approximately one hundred and fifty lasers in a concurrent research, development, and manufacturing environment, the reduction of residual oxygen incorporation in GRINSCH-SQW lasers was found to be in excellent correlation with lower threshold density, higher quantum well photoluminesence intensity, and secondary ion mass spectroscopy data. The high growth temperatures required to prevent oxygen incorporation in the quantum well result in additional technical obstacles stymieing full exploitation of the growth technology for use in the manufacture of integrated opto-electronic circuits and systems. The inherent difficulties in accurately measuring growth temperature in MBE systems and the gallium desorption during high temperature growth can lead to nonuniformities in cladding material composition. These nonuniformities can lead to an asymmetrical waveguiding structure with distorted optical output characteristics. Distortions in the radiated optical pattern can greatly affect the alignment and coupling efficiency between laser diodes and optical fibers or other electro-optical systems in integrated opto-electronic applications. A two-dimensional dielectric waveguide simulator has been used to analyze the optical properties of GRINSCH GaAs/AlGaAs lasers with asymmetrical cladding structures induced by noise in growth temperature measurement. Through this analysis, an optimal device structure which has the desired optical characteristics and is less sensitive to cladding composition asymmetries is demonstrated.
BTL Talks and Papers
Author: Bell Telephone Laboratories, inc. Technical Information Libraries
Publisher:
ISBN:
Category : Physics
Languages : en
Pages : 986
Book Description
Publisher:
ISBN:
Category : Physics
Languages : en
Pages : 986
Book Description
Molecular Beam Epitaxy of Aluminum Gallium Arsenide on Channeled Substrates
Author: Edward Allen Van Gieson
Publisher:
ISBN:
Category : Aluminum gallium arsenide
Languages : en
Pages : 278
Book Description
Publisher:
ISBN:
Category : Aluminum gallium arsenide
Languages : en
Pages : 278
Book Description
The Liquid Phase Epitaxial Growth Of Gallium Arsenide And Aluminium Gallium Arsenide For Double Heterostructure Laser Diodes
Author: Standen Nigel Douglas
Publisher:
ISBN:
Category : Gallium arsenide
Languages : en
Pages : 162
Book Description
Publisher:
ISBN:
Category : Gallium arsenide
Languages : en
Pages : 162
Book Description
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 702
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 702
Book Description
Mosaic
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 270
Book Description
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 270
Book Description
Bell Laboratories Talks and Papers
Author: Bell Telephone Laboratories, inc. Libraries and Information Systems Center
Publisher:
ISBN:
Category : Electrical engineering
Languages : en
Pages : 586
Book Description
Publisher:
ISBN:
Category : Electrical engineering
Languages : en
Pages : 586
Book Description
Energy Research Abstracts
Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 1408
Book Description
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 1408
Book Description
Journal of Current Laser Abstracts
Author:
Publisher:
ISBN:
Category : Lasers
Languages : en
Pages : 766
Book Description
Publisher:
ISBN:
Category : Lasers
Languages : en
Pages : 766
Book Description