Propagation of a short optical pulse through a dye solution under nonlinear dispersion conditions

Equations are proposed for the nonlinear interaction between optical pulses and dye solutions allowing for the contribution of the stimulated emission band to the nonlinear dispersion of the solution. A numerical solution of the equations showed that, for pulses having a carrier frequency near the absorption band of the solution, phase modulation of the pulses transmitted by the solution took the form of a deviation of the instantaneous frequency toward the red, and the "chirp" was positive.