This new and fully revised Fifth Edition of Fiber Optic Communications incorporates coverage of significant advances made in the fiber industry in recent years to present a comprehensive and in-depth introduction to the basics of communicating with optical fiber transmission lines. Readers will learn system design as well as operating principles, characteristics, and application of the components that comprise fiber-optic systems. New and expanded topics include Raman amplifier, erbium-doped waveguide amplifier, the arrayed waveguide grating, electroabsorption modulator, optical micro-electro-mechanical (MEMs) components, dispersion compensation, tunable light sources, tunable filters, optical time-division multiplexing, dense and course wavelength-division multiplexing, increased utilization of the optical spectrum, and emphasis on external modulation. Other topics include fiber lasers and optical amplifiers, vertical-cavity surface-emitting laser diodes, dense wavelength-division multiplexing, fiber Bragg grating technology, new component descriptions (fiber attenuator, circulator, and polarization controller), new phenomena descriptions (polarization mode dispersion, mode-partition noise), and power penalty.