Abstract

Erbium-doped fiber amplifiers are very promising active components in the field of optical communication since they offer polarization-insensitive high gain, broad bandwidth, and low insertion loss [1]-[3]. There are two types of erbium fiber amplifiers. One is a lumped amplifier [1]-[3] and the other is a distributed amplifier [4], [5]. The distributed erbium amplifiers offer very attractive prospects for the realization of ultralong loss-less transmission lines. For example, they can be applied to optical soliton communication as we pointed out in an earlier paper [6]. To achieve distributed amplifiers of longer than 10 km, the doping concentration is decreased to as low as a few ppm.

© 1990 Optical Society of America