This book covers main fiber lasers and amplifier devices based on rare-earth-doped silicia and flourozirconate fibers. It describes the erbium-doped fiber amplifier and its role as foundational in optical communication systems. This new edition is fully revised including new material on visible fluoride fiber lasers, single-frequency fiber lasers, broadband fiber sources, Qswitch fiber lasers, and rare-earth doped infrared-transmitting glass fibers. Three brand new chapters include high-power Ybdoped fiber lasers, Tm-doped mode-locked fiber lasers at 2um, and Ho-doped mode-locked fiber lasers.