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Design, simulation and analysis of laterally-longitudinally non-uniform edge-emitting GaAs-based diode lasers (Band 73)

2023-09-19
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Release : 2023-09-19
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Book Synopsis Design, simulation and analysis of laterally-longitudinally non-uniform edge-emitting GaAs-based diode lasers (Band 73) by : Jan-Philipp Koester

Download or read book Design, simulation and analysis of laterally-longitudinally non-uniform edge-emitting GaAs-based diode lasers (Band 73) written by Jan-Philipp Koester. This book was released on 2023-09-19. Available in PDF, EPUB and Kindle. Book excerpt: Edge-emitting quantum-well diode lasers based on GaAs combine a high conversion efficiency, a wide range of emission wavelengths covering a span from 630 nm to 1180 nm, and the ability to achieve high output powers. The often used longitudinal-invariant Fabry-Pérot-type resonators are easy to design but often lead to functionality or performance limitations. In this work, the application of laterally-longitudinally non-uniform resonator configurations is explored as a way to reduce unwanted and performance-limiting effects. The investigations are carried out on existing and entirely newly developed laser designs using dedicated simulation tools. These include a sophisticated time-dependent laser simulator based on a traveling-wave model of the optical fields in the lateral-longitudinal plane and a Maxwell solver based on the eigenmode expansion method for the simulation of passive waveguides. Whenever possible, the simulation results are compared with experimental data. Based on this approach, three fundamentally different laser types are investigated: • Dual-wavelength lasers emitting two slightly detuned wavelengths around 784 nm out of a single aperture • Ridge-waveguide lasers with tapered waveguide and contact layouts that emit light of a wavelength of around 970 nm • Broad-area lasers with slightly tapered contact layouts emitting at 910 nm The results of this thesis underline the potential of lateral-longitudinal non-uniform laser designs to increase selected aspects of device performance, including beam quality, spectral stability, and output power.

Design, Simulation and Analysis of Laterally-longitudinally Non-uniform Edge-emitting GaAs-based Diode Lasers

2023
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Release : 2023
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Book Rating : 829/5 ( reviews)

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Book Synopsis Design, Simulation and Analysis of Laterally-longitudinally Non-uniform Edge-emitting GaAs-based Diode Lasers by : Jan-Philipp Koester

Download or read book Design, Simulation and Analysis of Laterally-longitudinally Non-uniform Edge-emitting GaAs-based Diode Lasers written by Jan-Philipp Koester. This book was released on 2023. Available in PDF, EPUB and Kindle. Book excerpt:

Analysis of Spatio-Temporal Phenomena in High-Brightness Diode Lasers using Numerical Simulations

2020-10-22 Science
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Release : 2020-10-22
Genre : Science
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Book Rating : 894/5 ( reviews)

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Book Synopsis Analysis of Spatio-Temporal Phenomena in High-Brightness Diode Lasers using Numerical Simulations by : Anissa Zeghuzi

Download or read book Analysis of Spatio-Temporal Phenomena in High-Brightness Diode Lasers using Numerical Simulations written by Anissa Zeghuzi. This book was released on 2020-10-22. Available in PDF, EPUB and Kindle. Book excerpt: Broad-area lasers are edge-emitting semiconductor lasers with a wide lateral emission aperture. This feature enables high output powers but also diminishes the lateral beam quality and results in their inherently non-stationary behavior. Research in the area is driven by application, and the main objective is to increase the brightness, which includes both output power and lateral beam quality. To understand the underlying spatio-temporal phenomena and to apply this knowledge in order to reduce costs for brightness optimization, a self-consistent simulation tool taking all essential processes into account is vital. Firstly, in this work a quasi-three-dimensional opto-electronic and thermal model is presented that describes essential qualitative characteristics of real devices well. Time-dependent traveling-wave equations are utilized to characterize the inherently non-stationary optical fields, which are coupled to dynamic rate equations for the excess carriers in the active region. This model is extended by an injection-current-density model to accurately include lateral current spreading and spatial hole burning. Furthermore, a temperature model is presented that includes short-time local heating near the active region as well as the formation of a stationary temperature profile. Secondly, the reasons of brightness degradation, i.e. the origins of power saturation and the spatially modulated field profile, are investigated. And lastly, designs that mitigate those effects limiting the lateral brightness under pulsed and continuous-wave operation are discussed. Amongst those designs a novel “chessboard laser” is presented that utilizes longitudinal-lateral gain-loss modulation and an additional phase tailoring to obtain a very low far-field divergence.

Epitaxial Design Optimizations for Increased Efficiency in GaAs-Based High Power Diode Lasers

2021-04-09 Science
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Release : 2021-04-09
Genre : Science
Kind : eBook
Book Rating : 963/5 ( reviews)

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Book Synopsis Epitaxial Design Optimizations for Increased Efficiency in GaAs-Based High Power Diode Lasers by : Thorben Kaul

Download or read book Epitaxial Design Optimizations for Increased Efficiency in GaAs-Based High Power Diode Lasers written by Thorben Kaul. This book was released on 2021-04-09. Available in PDF, EPUB and Kindle. Book excerpt: This work presents progress in the root-cause analysis of power saturation mechanisms in continuous wave (CW) driven GaAs-based high-power broad area diode lasers operated at 935 nm. Target is to increase efficiency at high optical CW powers by epitaxial design. The novel extreme triple asymmetric (ETAS) design was developed and patented within this work to equip diode lasers that use an extremely thin p-waveguide with a high modal gain. An iterative variation of diode lasers employing ETAS designs was used to experimentally clarify the impact of modal gain on the temperature dependence of internal differential quantum efficiency (IDQE) and optical loss. High modal gain leads to increased free carrier absorption from the active region. However, less power saturation is observed, which must then be attributed to an improved temperature sensitivity of the IDQE. The effect of longitudinal spatial hole burning (LSHB) leads to above average non-linear carrier loss at the back facet of the device. At high CW currents the junction temperature rises. Therefore, not only the asymmetry of the carrier profile increases but also the average carrier density in order to compensate for the decreased material gain and increased threshold gain. This carrier non-pinning effect above threshold is found in this work to enhance the impact of LSHB already at low currents, leading to rapid degradation of IDQE with temperature. This finding puts LSHB into a new context for CW-driven devices as it emphasizes the importance of low carrier densities at threshold. The carrier density was effectively reduced by applying the novel ETAS design. This enabled diode lasers to be realized that show minimized degradation of IDQE with temperature and therefore improved performance in CW operation.

Simulation and Design of a Compact GaAs Based Tunable Dual-wavelength Diode Laser System

2019
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Release : 2019
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Book Synopsis Simulation and Design of a Compact GaAs Based Tunable Dual-wavelength Diode Laser System by : Jan-Philipp Koester

Download or read book Simulation and Design of a Compact GaAs Based Tunable Dual-wavelength Diode Laser System written by Jan-Philipp Koester. This book was released on 2019. Available in PDF, EPUB and Kindle. Book excerpt: We present our design of a compact, integrated and tunable dual-wavelength diode laser system emitting around 785 nm, which is of interest for several applications like Raman spectroscopy and the generation of THz radiation. To achieve a more compact device compared to previous GaAs based designs two etch depths are realized, leading to shallowly etched ridge waveguides in regions were optical gain is applied and deeply etched waveguides used to enable compact integrated waveguide components. The device parameters are optimized using a numerically efficient simulation tool for passive waveguides. Subsequently, the entire laser system is further analyzed applying a sophisticated traveling-wave equation based model for active devices giving access to internal intensity and carrier density distributions. It is shown that active laser simulations all-passive simulation.

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