Spatio-Temporal Modeling and Device Optimization of Passively Mode-Locked Semiconductor Lasers (Springer Theses)

✍ Scribed by Stefan Meinecke

• Publisher: Springer
• Year: 2022
• Tongue: English
• Leaves: 264
• Category: Library

✦ Synopsis

This thesis investigates passively mode-locked semiconductor lasers by numerical methods. The understanding and optimization of such devices is crucial to the advancement of technologies such as optical data communication and dual comb spectroscopy. The focus of the thesis is therefore on the development of efficient numerical models, which are able both to perform larger parameter studies and to provide quantitative predictions. Along with that, visualization and evaluation techniques for the rich spatio-temporal laser dynamics are developed; these facilitate the physical interpretation of the observed features.

The investigations in this thesis revolve around two specific semiconductor devices, namely a monolithically integrated three-section tapered quantum-dot laser and a V-shaped external cavity laser. In both cases, the simulations closely tie in with experimental results, which have been obtained in collaboration with the TU Darmstadt and the ETH Zurich. Based on the successful numerical reproduction of the experimental findings, the emission dynamics of both lasers can be understood in terms of the cavity geometry and the active medium dynamics. The latter, in particular, highlights the value of the developed simulation tools, since the fast charge-carrier dynamics are generally not experimentally accessible during mode-locking operation. Lastly, the numerical models are used to perform laser design explorations and thus to derive recommendations for further optimizations.

✦ Table of Contents

Supervisor’s Foreword
Abstract
Publications Related to This Thesis
Acknowledgements
Contents
Acronyms
1 Introduction
1.1 Dynamical Systems and Computational Physics
1.2 Semiconductor Lasers
1.3 Optical Pulse Trains and Frequency Combs
1.4 Thesis Outline
References
2 Semi-classical Laser Theory
2.1 Introduction
2.2 Traveling-Wave Equation for the Electric Field
2.3 Maxwell-Bloch Equations
2.4 Integration Scheme for the Traveling-Wave Equation
2.5 Integration Scheme with an Eliminated Polarization
References
3 Timing Jitter in Mode-Locked Lasers
3.1 Introduction
3.2 Time Domain Long-Term Timing Jitter Definition
3.3 Frequency Domain Timing Jitter Estimation Methods
3.3.1 The von der Linde Method
3.3.2 The Kéfélian Method
3.3.3 Numerical Application to the Three-Section Laser
3.4 Hybrid Long-Term Timing Jitter Estimation Methods
3.5 The Pulse-Period Fluctuation Autocorrelation Method
3.5.1 Guidelines to Calculate the Long-Term Timing Jitter
3.6 Computational Timing Jitter Estimation Efficiency
3.7 Chapter Conclusions
References
4 Three-Section Tapered Quantum-Dot Laser
4.1 Introduction
4.1.1 Investigated Device
4.1.2 Chapter Outline
4.2 Three-Section Tapered Quantum-Dot Laser Model
4.3 Basic Emission States
4.3.1 Illustration of the Mode-Locked Emission States
4.3.2 Net-Gain Analysis
4.3.3 Spatio-Temporal Dynamics
4.4 Comparison to Experimental Measurements
4.4.1 Experimental Setup and Characterization
4.4.2 Juxtaposition of Experimental and Simulated Results
4.5 Emission Dynamics in the Operation Parameter Space
4.5.1 Pump Current and Reverse Bias Dependence
4.5.2 Understanding the Absorber Reverse Bias
4.5.3 Spontaneous Emission Noise Induced Dynamics
4.6 Timing Jitter Analysis
4.6.1 Spontaneous Emission Noise Dependence of the Timing Jitter
4.6.2 Timing Jitter Along the Pulse Propagation
4.6.3 Timing Jitter in the Operation Parameter Space
4.7 Tuning the Taper Angle
4.7.1 Emission Dynamics and Pulse Performance
4.7.2 Pulse-Shaping Along the Taper Angle and Pump Current
4.7.3 Taper Angle Dependence of the Timing Jitter
4.8 Shifting the Saturable Absorber Position
4.8.1 Emission Dynamics and Pulse Performance
4.8.2 Pulse Shaping Along the Absorber Position
4.8.3 Absorber Starting Position Dependence of the Timing Jitter
4.9 Chapter Conclusions
References
5 V-Shaped External Cavity Laser
5.1 Introduction
5.1.1 V-Shaped External Cavity Semiconductor Lasers
5.1.2 Experimentally Observed Emission States
5.1.3 Chapter Outline
5.2 V-Shaped External Cavity Laser Model
5.2.1 V-Shaped External Cavity
5.2.2 Quantum-Well Active Medium
5.3 Symmetric Cavity Dynamics Characterization
5.3.1 Basic Mode-Locking States
5.3.2 Pump Current Dependence of the Emission Dynamics
5.3.3 Unsaturated Absorption Dependence of the Emission Dynamics
5.3.4 Gain Bandwidth Dependence of the Emission Dynamics
5.4 Asymmetric Cavity Configurations
5.4.1 Emission States for Asymmetric Cavity Configurations
5.4.2 Discussion of the Experimental Results
5.4.3 Pulse Performance Dependence on the Cavity Asymmetry
5.4.4 Fundamental Mode-Locking Stability Boundary
5.5 Chapter Conclusions
References
6 Summary and Outlook
References