Distributed erbium-doped fiber amplifier for soliton transmission

The variations of the soliton power in distributed erbium-doped fiber amplifiers are numerically studied. There exists a doping density for minimum power variation. The results show that a soliton of short pulse width can maintain its pulse shape well in cascaded distributed amplifiers with a proper doping density, but an optical filter between the amplifiers is required for maintenance of the neighboring soliton separation.