3 Chapter – Components

TL;DR: In this article, the physical principles behind the operation of optical communication systems are discussed, including couplers, optical amplifiers, optical switches, filters, and multiplexers.

Abstract: Publisher Summary This chapter discusses the physical principles behind the operation of the most important components of optical communication systems. For each component, a simple descriptive treatment is presented followed by a more detailed mathematical treatment. The components used in modern optical networks include couplers, lasers, photodetectors, optical amplifiers, optical switches, filters, and multiplexers. Couplers are simple components used to combine or split optical signals. The chapter then discusses filters and multiplexers, which are used to multiplex and demultiplex signals at different wavelengths in wavelength division multiplexing (WDM) systems. It also describes various types of optical amplifiers, which are key elements used to overcome fiber and other component losses and can also be used to amplify signals at multiple wavelengths. Understanding filters and optical amplifiers is essential to understanding the operation of lasers, which is explained in this chapter. The chapter discusses photodetectors, which convert the optical signal back into the electrical domain. Thereafter, it explains optical switches, which play an important role as optical networks become more agile. Finally, it discusses wavelength converters, which are used to convert signals from one wavelength to another, at the edges of the optical network, as well as inside the network.