Book excerpt: Beginning with an overview of historical development, the electromagnetic spectrum, and optical power basics, this book offers an in-depth discussion of optic receivers, optical transmitters and amplifiers. The text discusses attenuation, transmission losses, optical sources such as semiconductor light emitting diodes, and lasers, providing several dispersion-management schemes that restore the amplified signal to its original state. Topics are discussed in a structured manner, with definitions, explanations, examples, illustrations, and informative facts. Extensive pedagogical features, such as numerical problems, review questions, multiple choice questions, and student-focussed learning objectives, are also provided. Mathematical derivations and geometrical representations are included where necessary. This text will be useful for undergraduate and graduate students of electronics, communication engineering, and optical fiber communications.