Vol. 44, Issue 2, pp. 251-266 (2014)

Abstract

Optical amplifiers are realised in a wide range of applications, such as metro – dense wavelength division multiplexing and cable television networks. These applications require the amplifier to provide a maximum output power level by accepting an input power near the saturation level. To obtain an ideal amplifier according to several parameters, the erbium concentration in the composite core glass, the optimum length of the fibre, the pump saturation and the input signal signal-to-noise ratio must be critically studied and addressed. In this paper, we will review the types of optical amplifiers used in communication systems today as well as the parameters that limit the performance of optical amplifiers in the network, such as the noise figure, the gain saturation, the polarisation dependence gain and inhomogeneous broadening effects. Based on the performance limitation factor, we model the amplifier gain profile and the effect of the gain value on the network performance. Finally, we propose various configurations of an optical amplifier, and the advantages of each amplification technique are highlighted.