Generation and control of solitons and solitonlike pulses in a femtosecond ring dye laser.

We control the generation of solitons and solitonlike pulses in a passively mode-locked dye laser by adjustment of group-velocity dispersion, self-phase modulation, and spectral filtering. Without spectral filtering, periodic pulse shaping reminiscent of higher-order solitons is observed. The pulses differ from the classic solitons because of additional shaping mechanisms. With spectral filtering, pulses are generated that can be described analytically as asymmetric N = 2 solitons. The results indicate an effect analogous to the soliton self-frequency shift observed in optical fibers. The remarkable stability achieved allows for accurate characterization and control.