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

Koester, Jan-Philipp

• Publisher: Cuvillier Verlag
• Year: 2023
• eBook ISBN:
  9783736968830
• Print ISBN:
  9783736978829
• Edition: 1

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 nmThe 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.

Table of contents

• Chapter 1 Introduction and background
• Chapter 2 Wave propagation in opticalwaveguides
• 2.1 Maxwell’s and wave equations
• 2.2 Waveguide modes
• 2.3 Local modes and modal decomposition
• 2.4 Integrated waveguide components
• Chapter 3 Simulation models
• 3.1 Traveling-wave model based laser simulation
• 3.2 Eigenmode expansion method
• 3.3 Beam propagation method
• Chapter 4 MMI-coupler-baseddual-wavelength lasers
• 4.1 Introduction
• 4.2 Device design
• 4.3 Integrated waveguide component optimization
• 4.4 Experimental device characterization
• 4.5 Complementary results and discussion
• 4.6 Chapter summary
• Chapter 5 High-brightness taperedridge-waveguide lasers
• 5.1 Introduction
• 5.2 Device design
• 5.3 Straight ridge-waveguide laser
• 5.4 Tapered ridge-waveguide laser
• 5.5 Design optimization
• 5.6 Chapter summary
• Chapter 6 Efficient high-power taperedbroad-area lasers
• 6.1 Introduction
• 6.2 Device design
• 6.3 Electro-optical characteristics
• 6.4 Intra-cavity intensity, carrier density and temperaturedistributions
• 6.5 Local gain, modal analysis and beam quality
• 6.6 Chapter summary
• Chapter 7 Summary and conclusion
• Appendix
• A: Simulation parameters
• B: Finite-difference method 1D modesolver
• C: Conformal mapping of bent waveguides
• D: Simulation of low index contrast waveguide bends
• Bibliography
• List of abbreviations
• List of publications
• Acknowledgment