Managing Self-Phase Modulation in Pseudo-Linear Multimodal and Monomodal Systems

We propose a new semi-analytical model, describing the bandwidth evolution of pulses propagating in dispersion managed (DM) transmission systems using multimodal graded-index fibers (GRIN) with parabolic index. The model also applies to monomodal fiber DM systems, representing limit case where beam self-imaging vanishes. is successfully compared direct integration (1+1)D nonlinear Schr\"odinger equation for GRIN fibers, and experimental results performed by femtosecond over 5 m span fiber. At high pulse powers that are possible variations produced interplay cumulated self-phase modulation can become most detrimental effect, if not properly managed. analytical numerical all point existence an optimal amount chromatic dispersion, must be provided input pulse, obtaining periodic its bandwidth. Results promising generation spatio-temporal solitons stable, time-bandwidth behaviour was already observed added characteristic spatial self-imaging.