A survey on rare earth doped optical fiber amplifiers

The rare-earth-doped fiber amplifier (REDFA) has a significant role in the development of worldwide fiber-optic networks. This paper present a survey on the introduction to the history of the rare earth doped optical fiber amplifier as well as the context within which fiber amplifiers are having a very significant commercial impact along with its use as an amplifier. The most significant points in any optical amplifier design are gain and noise figure (NF), low NF and high gain are the main features for optimum REDFA. The emergence of the fiber amplifier indicates the invention and development of further guided wave devices that should play a major role in the continuing increase in transmission capacity and functionality of the fibers.