Date Added: Sep 2011
The reliability of the entire communications network is dependent on the reliability of each single element. Even though redundant transmission systems allow higher reliability, the OPEX (OPerational EXpenditure) caused by maintenance costs can be minimized if reliable components are used. Capacity of optical communications networks has increased rapidly in the past several years. Accordingly, the requirements of fiber links have risen, especially with the introduction of Wavelength Division Multiplexing (WDM), more powerful optical fiber amplifiers and the recently emerging Raman amplification schemes.