This book provides a comprehensive analysis of quantum-confined semiconductor lasers, focusing on quantum dot lasers (QDLs) and interband quantum cascade lasers (ICLs). Through theoretical and numerical exploration, the author scrutinizes the amplitude and frequency noise spectra, studies the dynamics induced by delayed optical reinjection, and investigates the generation of squeezed states for both laser types. Notably, his predictions align with experimental results, demonstrating the robustness of this approach. Structured meticulously, the book begins with an overview of QDL and ICL technology, followed by in-depth chapters on classical noise and dynamics, and quantum aspects, particularly the generation of squeezed states. Clearly written, the text strikes a balance between words and equations, maintaining accessibility without sacrificing depth. It includes an extensive bibliography, a testament to the thoroughness of the research and a useful feature for all newcomers to the field.