Author: Jay Prakash Gupta
Publisher: ProQuest
ISBN: 9780549926825
Category : Aluminum
Languages : en
Pages :
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There is demand for a robust, compact and sensitive gyroscope which can be utilized as a navigational tool for modern commercial and military applications, as well as there is a need of constant improvement in performance and reduction in bulk and weight of the gyroscope at the same time. A compact integrated design based on semiconductor materials has the highest hope of meeting the measurement conditions for military and commercial applications as well as providing the potential for low cost, high volume manufacturing. To this end, my work focuses on fabrication and characterization of one of the key elements of a GaAs / AlGaAs semiconductor ring laser (SRL) gyroscope, SRL. The goal of the thesis is to fabricate a SRL with characteristics required for its use in a SRL gyroscope. In this thesis, I first describe the working principle of the SRL gyroscope. The lock-in in the SRL is explained and an approach to break the lock-in is described. Then the effort put into the fabrication of SRL, problems faced and methods used to rectify them is described in detail. Afterwards, I explain the test setup built to characterize the fabricated SRLs. Finally, I quantify the results obtained by characterizing the fabricated structures and research to follow in the future.
Author: Dean Winston Barker
Publisher:
ISBN:
Category : Bipolar transistors
Languages : en
Pages : 474
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Author: Kevin John Beernink
Publisher:
ISBN:
Category :
Languages : en
Pages : 106
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Author: Carsten Lindström
Publisher:
ISBN:
Category : Lasers
Languages : en
Pages : 107
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Author: Saied Tadayon
Publisher:
ISBN:
Category :
Languages : en
Pages : 466
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Author: Melih Özaydin
Publisher:
ISBN:
Category :
Languages : en
Pages : 264
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Author: David Constantine Radulescu
Publisher:
ISBN:
Category : Doped semiconductors
Languages : en
Pages : 578
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Author: Sridhar V. Iyer
Publisher:
ISBN:
Category :
Languages : en
Pages :
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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.
Author: Timothy James Drummond
Publisher:
ISBN:
Category :
Languages : en
Pages : 58
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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.
Author:
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ISBN:
Category :
Languages : en
Pages :
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