Chapter 3 - Communication With Optics

Abstract

This chapter introduces the basic concepts of fiber-optic communications. With the advent of optic fibers and corresponding components such as semiconductor lasers and receivers, fiber-optic communication has become the core technology for long haul broadband communications The basic principle of light propagating in optic fiber can be illustrated by the simple geometric optics principle, i.e., total internal reflection. The light sources to be used for fiber-optic communications must have the following unique properties: proper output wavelengths, narrow bandwidth, and high-energy efficiency and compact size. Besides optical fibers, transmitters, and receivers, there are also other components needed in fiber-optic networks, including optical couplers, switchers, amplifiers, isolators, dispersion compensators, and more. To ensure good performance, it is very important to test the functioning of optics networks. The most important parameter of a digital system is the rate at which errors occur in the system. A common evaluation is the bit error ratio (BER) test. Another link evaluation is clock jitter measurement. The fiber–optic system can add variability to the unit interval period, referred to as jitter.