The Second Edition contains two additional chapters one on optical fiber sensors and the other on optical fiber networks. These additions together with the material of the first edition provide a comprehensive treatment of optical fiber communication systems and their applications. The material is well presented and is designed for undergraduate students pursuing courses in electrical engineering, and electronics and telecommunication engineering. The book offers a completely up to date, accessible, and in depth introduction to the principles and applications of optical fiber communications. It describes the recent developments in optical fiber communication materials, devices, components, and systems. The coverage includes key concepts such as properties of light, semiconductor materials, photon sources, optical receivers, LED and laser transmitters, optical homodyne and heterodyne detection systems, polarization penalty, connectorization and losses in optical fiber, photon photon multiplexing using WDM and integrated optics, built-up of long haul OFC link at 8 Mbps and 2.5 Gbps, optical fiber applications in LAN/WAN and CCTV, underneath sea communication and long haul optical fiber communication.