NONLINEAR SELF-PHASE MODULATION IN OPTICAL SOLITON SYSTEMS WITH LUMPED AMPLIFIERS

The nonlinear Schrodinger equation, governing pulse propagation in los sy optical fibers with periodic amplification, is analyzed under the a verage soliton concept. Bright and dark solitons solutions, correspond ing to separatrices of one-dimensional hamiltonian dynamical systems, have been derived. The shift of the soliton velocity, relative to the group velocity, as well as the effect of nonlinear self-phase modulati on on the angular frequency and the wavenumber are investigated. The o btained results are connected with the initial pulse amplitude and its spatial and temporal derivatives.