Formation and propagation of chirped optical soliton

We give the expression of the input experimental pulse, numerically study formation and propagation of chirped soliton according to the nonlinear propagation theory by use of the split-step Fourier method. The numerical results are consistent with the experimental data. The pulse can evolve into chirped soliton after propagating over 3.5 dispersion length, the temporal FWHM and chirp gradually decreases with increase of input power. The temporal FWHM of chirped soliton executes a kind of damped oscillation with increase of propagation distance whose period and amplitude decrease with increase of input power, the temporal waveform always maintain near hyperbolic secant pulse during nonlinear propagation.