This book is intended as an undergraduate/postgraduate level textbook for courses on high-speed optical networks as well as computer networks. Nine chapters cover the basic principles of the technology and different devices for optical networks, as well as processing of integrated waveguide devices of optical networks using different technologies. It provides students, researchers and practicing engineers with an expert guide to the fundamental concepts, issues and state-of-the-art developments in optical networks. It includes examples throughout all the chapters of the book to aid understanding of basic problems and solutions. Presents basics of the optical network devices and discusses latest developments Includes examples and exercises throughout all the chapters of the book to aid understanding of basic problems and solutions for undergraduate and postgraduate students Discusses different optical network node architectures and their components Includes basic theories and latest developments of hardware devices with their fabrication technologies (such as optical switch, wavelength router, wavelength division multiplexer/demultiplexer and add/drop multiplexer), helpful for researchers to initiate research on this field and to develop research problem-solving capability Reviews fiber-optic networks without WDM and single-hop and multi-hop WDM optical networks P. P. Sahu received his M.Tech. degree from the Indian Institute of Technology Delhi and his Ph.D. degree in engineering from Jadavpur University, India. In 1991, he joined Haryana State Electronics Development Corporation Limited, where he has been engaged in R&D works related to optical fiber components and telecommunication instruments. In 1996, he joined Northeastern Regional Institute of Science and Technology as a faculty member. At present, he is working as a professor in the Department of Electronics and Communication Engineering, Tezpur Central University, India. His field of interest is integrated optic and electronic circuits, wireless and optical communication, clinical instrumentation, green energy, etc. He has received an INSA teacher award (instituted by the highest academic body Indian National Science Academy) for high level of teaching and research. He has published more than 90 papers in peer-reviewed international journals, 60 papers in international conference, and has written five books published by Springer Nature, McGraw-Hill. Dr Sahu is a Fellow of the Optical Society of India, Life Member of Indian Society for Technical Education and Senior Member of the IEEE.