Optical Fiber and the Fiber Channel

The enormous potential of the fiber-optic channel to transmit data over long distances at high rates has been gradually unlocked by means of a number of key technological innovations underpinned by the mature understanding of lightwave propagation in optical fibers. This chapter reviews the main properties of the fiber-optic channel, starting from the structure of ideal linear optical fibers and proceeding to the derivation of the equations governing signal propagation in single-mode fibers in the presence of various physical phenomena. These are chromatic dispersion, attenuation and amplification, polarization-mode dispersion, polarization-dependent loss, and nonlinear distortions. In the context of nonlinear propagation, the chapter also provides an introduction to the modeling of the nonlinear interference noise in coherent systems that are used today. The chapter targets readers who are familiar with the fundamental concepts involved in the study of electromagnetic fields and signal theory but have no specific background on fiber-optic transmission. It consists of five sections that are largely self-contained but with references used to avoid long derivations and maintain brevity.