André Röhm investigates the dynamic properties of two-state lasing quantum dot lasers, with a focus on ground state quenching. With a novel semi-analytical approach, different quenching mechanisms are discussed in an unified framework and verified with numerical simulations. The known results and experimental findings are reproduced and parameter dependencies are systematically studied. Additionally, the turn-on dynamics and modulation response curves of two-state lasing devices are presented.

This thesis examines the unique properties of gallium arsenide (GaAs)-based quantum-dot semiconductor optical amplifiers for optical communication networks, introducing readers to their fundamentals, basic parameters and manifold applications. The static and dynamic properties of these amplifiers are discussed extensively in comparison to conventional, non quantum-dot based amplifiers, and their unique advantages are elaborated on, such as the fast carrier dynamics and the decoupling of gain and phase dynamics. In addition to diverse amplification scenarios involving single and multiple high symbol rate amplitude and phase-coded data signals, wide-range wavelength conversion as a key functionality for optical signal processing is investigated and discussed in detail. Furthermore, two novel device concepts are developed and demonstrated that have the potential to significantly simplify network architectures, reducing the investment and maintenance costs as well as the energy consumption of future networks.

This thesis sheds light on the unique dynamics of optoelectronic devices based on semiconductor quantum-dots. The complex scattering processes involved in filling the optically active quantum-dot states and the presence of charge-carrier nonequilibrium conditions are identified as sources for the distinct dynamical behavior of quantum-dot based devices. Comprehensive theoretical models, which allow for an accurate description of such devices, are presented and applied to recent experimental observations. The low sensitivity of quantum-dot lasers to optical perturbations is directly attributed to their unique charge-carrier dynamics and amplitude-phase-coupling, which is found not to be accurately described by conventional approaches. The potential of quantum-dot semiconductor optical amplifiers for novel applications such as simultaneous multi-state amplification, ultra-wide wavelength conversion, and coherent pulse shaping is investigated. The scattering mechanisms and the unique electronic structure of semiconductor quantum-dots are found to make such devices prime candidates for the implementation of next-generation optoelectronic applications, which could significantly simplify optical telecommunication networks and open up novel high-speed data transmission schemes.

André Röhm investigates the dynamic properties of two-state lasing quantum dot lasers, with a focus on ground state quenching. With a novel semi-analytical approach, different quenching mechanisms are discussed in an unified framework and verified with numerical simulations. The known results and experimental findings are reproduced and parameter dependencies are systematically studied. Additionally, the turn-on dynamics and modulation response curves of two-state lasing devices are presented. Contents Quantum Dot Laser Theory Two-State Lasing and Ground-State Quenching Modulation Response Target Groups Researchers and students in the field of theoretical physics Practitioners in this area The Author André Röhm wrote his master's thesis under the supervision of Prof. Dr. Eckehard Schöll, PhD and Prof. Dr. Kathy Lüdge in the Collaborative Research Center SFB 910 at the Institute of Theoretical Physics at TU Berlin.

In this monograph, the authors address the physics and engineering together with the latest achievements of efficient and compact ultrafast lasers based on novel quantum-dot structures and devices. Their approach encompasses a broad range of laser systems, while taking into consideration not only the physical and experimental aspects but also the much needed modeling tools, thus providing a holistic understanding of this hot topic.

Written by a team of European experts in the field, this book addresses the physics, the principles, the engineering methods, and the latest developments of efficient and compact ultrafast lasers based on novel quantum-dot structures and devices, as well as their applications in biophotonics. Recommended reading for physicists, engineers, students and lecturers in the fields of photonics, optics, laser physics, optoelectronics, and biophotonics.

This thesis deals with the dynamics of state-of-the-art nanophotonic semiconductor structures, providing essential information on fundamental aspects of nonlinear dynamical systems on the one hand, and technological applications in modern telecommunication on the other. Three different complex laser structures are considered in detail: (i) a quantum-dot-based semiconductor laser under optical injection from a master laser, (ii) a quantum-dot laser with optical feedback from an external resonator, and (iii) a passively mode-locked quantum-well semiconductor laser with saturable absorber under optical feedback from an external resonator. Using a broad spectrum of methods, both numerical and analytical, this work achieves new fundamental insights into the interplay of microscopically based nonlinear laser dynamics and optical perturbations by delayed feedback and injection.