ABSTRACT
This chapter provides a brief overview of the basic architectures and properties of the most widely used type of optical transmission line, which exploit the enormous bandwidth of optical fiber by a general technique called wavelength division multiplexing (WDM). It examines the various physical mechanisms that limit the performance of WDM systems, in particular, their output power, capacity, optical reach, and cost. Chromatic dispersion is no more in line compensated, which eliminates the dispersion-compensation fiber in each amplification site, polarization mode dispersion (PMD), which was a very serious problem can be compensated for very efficiently. The emphasis is placed on the main performance-limiting effects, namely fiber optical nonlinearities, fiber chromatic and group velocity dispersions (GVDs), optical amplifier noise and noise accumulation, and receiver noise. Stimulated Brillouin scattering (SBS) belongs to the family of parametric amplification processes.
