This modern text provides detailed coverage of the important physical processes underpinning semiconductor devices. Advanced analysis of the optical properties of semiconductors without the requirement of complex mathematical formalism allows clear physical interpretation of all obtained results. The book describes fundamental aspects of solid-state physics and the quantum mechanics of electron-photon interactions, in addition to discussing in detail the photonic properties of bulk and quantum well semiconductors. The final six chapters focus on the physical properties of several widely-used photonic devices, including distributed feedback lasers, vertical-cavity surface-emitting lasers, quantum dot lasers, and quantum cascade lasers. This book is ideal for graduate students in physics and electrical engineering and a useful reference for optical scientists.