Propagation of chirped rectangular pulses in nonlinear lossless optical waveguide

Propagation of the chirped ultra-short optical pulses in nonlinear lossless optical waveguide is discussed. The nonlinear Schrodinger equation is solved numerically for complex initial conditions using beam propagation method. In order to calculate the stationary peak value of the envelope, an averaging filter was used, and estimated critical value of the chirp parameter was calculated with the use of rational extrapolation algorithm in case of rectangular initial pulse.