Erbium doped fiber amplifiers for future undersea transmission systems

Results obtained with analytical models of erbium-doped fiber amplifiers (EDFAs), which have potential as repeaters in lightwave transmission system, are summarized. The results pertain to the dispersion and noise characteristics of the amplifiers. Experimental results that verify some of the analysis are examined. The results show that EDFA systems are promising for undersea applications. Large dispersion penalties can be avoided by using dispersion-shifted fiber and transform-limited pulses placed close to the fiber´s zero dispersion wavelength. Noise can be controlled by optical filters between the amplifiers or in front of the receiver, or both.<>