1# Library to Find Best eBook for Read
Author : Mohamed Elattar
Release : 2024
Genre :
Kind : eBook
Book Rating : /5 ( reviews)
Book Synopsis High-power GaAs-based Diode Lasers with Novel Lateral Designs for Enhanced Brightness, Threshold and Efficiency by : Mohamed Elattar
Download or read book High-power GaAs-based Diode Lasers with Novel Lateral Designs for Enhanced Brightness, Threshold and Efficiency written by Mohamed Elattar. This book was released on 2024. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Thorben Kaul
Release : 2021-04-09
Genre : Science
Kind : eBook
Book Rating : 963/5 ( reviews)
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.
Author : Roland Diehl
Release : 2003-07-01
Genre : Science
Kind : eBook
Book Rating : 523/5 ( reviews)
Book Synopsis High-Power Diode Lasers by : Roland Diehl
Download or read book High-Power Diode Lasers written by Roland Diehl. This book was released on 2003-07-01. Available in PDF, EPUB and Kindle. Book excerpt: Starting from the basics of semiconductor lasers with emphasis on the generation of high optical output power the reader is introduced in a tutorial way to all key technologies required to fabricate high-power diode-laser sources. Various applications are exemplified.
Author : Jan-Philipp Koester
Release : 2023-09-19
Genre :
Kind : eBook
Book Rating : 825/5 ( reviews)
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.
Author : Carlo Frevert
Release : 2019-07-11
Genre : Science
Kind : eBook
Book Rating : 44X/5 ( reviews)
Book Synopsis Optimization of broad-area GaAs diode lasers for high powers and high efficiencies in the temperature range 200-220 K by : Carlo Frevert
Download or read book Optimization of broad-area GaAs diode lasers for high powers and high efficiencies in the temperature range 200-220 K written by Carlo Frevert. This book was released on 2019-07-11. Available in PDF, EPUB and Kindle. Book excerpt: This work focuses on the development of AlGaAs-based diode laser (DL) bars optimized for reaching highest powers and efficiencies at low operation temperatures. Specifically, the quasi continuous wave (QCW) pumping of cryogenically cooled Yb:YAG solid-state lasers is targeted, setting requirements on the wavelength (940 nm), the pulse conditions (pulse length 1.2 ms) and frequency (10 Hz) as well as the lowest DL operating temperature THS ~ 200 K, consistent with economic cooling. High fill-factor bars for QCW operation are to reach high optical performance with optical output powers of P 1.5 kW and power conversion efficiencies of ŋE 60% at these power levels. Understanding the efficiency-limiting factors and the behavior at lower temperatures is necessary to design these devices. Optimizations are performed iteratively in three stages. First, vertical epitaxial designs are studied theoretically, adjusted to the targeted operation temperatures and specific laser parameters are extracted. Secondly, resulting vertical designs are processed into low power single emitters and their electro-optical behavior at low currents is experimentally assessed over a wide range of temperatures. The obtained laser parameters characteristic to the vertical design are then used to extrapolate the laser's performance up to the high targeted currents. Finally, vertical designs promising to reach the targeted values for power and efficiency are processed into high power single emitters and bars which are measured up to the highest currents. Eventually, laser bars are fabricated reaching output powers of 2 kW and efficiencies of 61% at 1.5 kW at an operation temperature of 203 K.
