Optical Fibers

Summary

This chapter focuses on the role of optical fibers as a communication channel in lightwave systems. It utilizes geometrical‐optics description to explain the guiding mechanism and introduce the related basic concepts. Geometrical optics can be used to show that a parabolic‐index profile leads to nondispersive propagation within the paraxial approximation. The chapter considers propagation of electromagnetic waves inside step‐index fibers, and introduces Maxwell’s equations. It focuses on how an optical fiber can be designed to support only a single mode and describes the properties of such single‐mode fibers. The chapter discusses how the group‐velocity dispersion limits the performance of lightwave systems employing single‐mode fibers. Power loss within a fiber link represents a major limiting factor because it reduces the signal’s power reaching the receiver. The chapter also discusses the nonlinear phenomena that are most relevant for fiber‐optic communications and the engineering aspects of optical fibers made using either silica glass or a suitable plastic material.