Linear Noise Characteristics.

Spontaneous emission is the inevitable consequence of gain in an optical amplifier. In this chapter, the definition of noise figure is shown to be useful only in characterizing shot noise and signal-spontaneous beat noise. The noise characteristics of both discrete and distributed Raman amplifiers are then presented. The choice of discrete amplifiers alone, or together with distributed optical amplifiers results as a trade-off between maximizing optical signal-to-noise ratio at the expense of increases in nonlinear distortion of the signal due to high signal intensities. Hansen et al. [1] showed that distributed amplification could be used to obtain a significant improvement in system margin that could be used to upgrade the transmission capacity, either in terms of more channels, or a faster line rate. [ABSTRACT FROM AUTHOR]