ABSTRACT
This chapter presents the fundamentals of optical amplifiers (OAs), their characteristics and classifications of common ones and it describes their applications. The three basic technologies are: erbium-doped fibre optical amplifiers (EDFAs), semiconductor optical amplifiers (SOAs) and Raman OAs. These technologies and applications are presented in detail in the chapter. OAs are used to boost signals transmitted over long distances in network systems. The characteristics and advantages of the OAs have led to many applications. OAs can be used to boost signal power after multiplexing, or before de-multiplexing or at any point in modern optical networks. OAs are ideal for Merto and Long – Haul dense wavelength multiplexing (DWDM) as well as single wavelength applications. There are many other types of OAs under research and development. The main objective is to increase the wavelength range and to increase the bit rates in communication systems along with improving the performance and decreasing the cost.
