Book excerpt: Optical Waveguide Technology and Applications encompasses both fundamental theory and engineering applications, appealing to a wide range of interests, from classical approaches to emerging modern research topics in related fields. This book is a collection of contemporary research and developments in optical waveguide technology and applications. It features seven carefully selected chapters organized into two sections: “Optical Sensing” and “Waveguiding Media.” Chapters address such topics as fiber optical sensing techniques and their underlying theory and applications, integrated optical waveguide structures and performances, waveguides in magnetism and spintronics, graphene-based surface plasmonics, optical waveguides in quantum computations, and optical waveguide fabrication processes.