Nonsoliton pulse evolution in normally dispersive fibers

For a typical nonreturn-to-zero pulse propagating in existing normally disp ersive fibers, we provide a uniform description of the optical transmission . There are three distinct regimes of the governing nonlinear Schrodinger e quation: the fully nonlinear dispersive regime, which covers a small region of the pulse, and two limiting asymptotic regimes, namely, nonlinear, weak ly dispersive (for the hulk of the pulse) and linear dispersive (for the ta ils). For prediction of pulse degradation, the asymptotic regimes admit acc urate, simplified models for both nonlinear-dispersive pulse spreading and the onset of optical shacks and oscillations at the fronts. (C) 1999 Optica l Society of America [S0740-3224(99)03711-X].