Optical Communications, 2nd Edition

8

FIBER NETWORKS

The ability to transmit high data rates over thin fiber cable lines has made optical fibers important in communication networking. In typical optical communication networks, multiple sets of optical transmitters and receivers are interconnected by optical fiber to permit independent information flow to be simultaneously dispersed among the set.

Fiber networks may involve interconnections among devices that can be (1) confined to a specific location such as a single building (local area network, LAN), (2) spread between several buildings, say, within a city (metropolitan area networks, MAN), or (3) spread over an entire continent (wide area networks, WAN). Thus a network may involve individual links that may span meters, hundreds of meters, or thousands of meters. In this chapter, we examine some of the communication characteristics of general forms of fiber networks, and examine the relationships between the optical parameters and the key network performance parameters. The most important communication parameters of any network are (l) the size (number of simultaneous links) that can be sustained, (2) the data rate of each link, and (3) the accuracy of the transmitted data. Secondary aspects, such as complexity, latency (delays), and cost issues may also become important, depending on the application of the network, but are not pursued here.