Abstract
A scheme for the reshaping of ultrashort solitons in a lossy fiber, based on abrupt increase of the fiber’s dispersion just before application of a strong amplification pulse and on further gradual return of the dispersion to the bulk value, is proposed. The enhanced dispersion can be matched to the gain so that the amplified solitary wave will always be an exact soliton with no radiation. With the adiabatic invariant technique, it is demonstrated that the soliton will smoothly evolve down to the bulk value of the dispersion without being disturbed and that the scheme is stable against spontaneous chirp generation.