Fiber-optic communication systems have advanced dramatically over the last four decades, since the era of copper cables, resulting in low-cost and high-bandwidth transmission. Fiber optics is now the backbone of the internet and long-distance telecommunication. Without it we would not enjoy the benefits of high-speed internet, or low-rate international telephone calls. This book introduces the basic concepts of fiber-optic communication in a pedagogical way. The important mathematical results are derived by first principles rather than citing research articles. In addition, physical interpretations and real-world analogies are provided to help students grasp the fundamental concepts. Key Features: * Lucid explanation of key topics such as fibers, lasers, and photodetectors. * Includes recent developments such as coherent communication and digital signal processing. * Comprehensive treatment of fiber nonlinear transmission. * Worked examples, exercises, and answers. * Accompanying website with PowerPoint slides and numerical experiments in MATLAB. Intended primarily for senior undergraduates and graduates studying fiber-optic communications, the book is also suitable as a professional resource for researchers working in the field of fiber-optic communications.