chapter 3 – Components

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

Abstract: Publisher Summary Couplers, isolators, and circulators are all commodity components. Many of the optical filters are commercially available, with fiber gratings, thin-film multicavity filters, and arrayed waveguide gratings used in commercial WDM systems. 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 followed by a more detailed mathematical treatment is given. The components used in modern optical networks include couplers, lasers, photodetectors, optical amplifiers, optical switches, and filters and multiplexers. Couplers are simple components used to combine or split optical signals. Filters and multiplexers are used to multiplex and demultiplex signals at different wavelengths in WDM systems. Various types of optical amplifiers, which are key elements used to overcome fiber and other component losses are described in the chapter. In many cases, these can be used to amplify signals at multiple wavelengths. Understanding filters and optical amplifiers is essential to understanding the operation of lasers, which comes next. Semiconductor lasers are the main transmitters used in optical communication systems. Photodetectors and optical switches are also discussed. 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 are described in this discussion.