Solitons and related periodic pulse evolutions in a femtosecond ring dye laser

The generation of solitons and other related periodic pulse evolutions in a passively mode-locked dye laser is controlled by adjustment of group velocity dispersion, self-phase modulation, and spectral filtering. Without spectral filtering, periodic pulse evolutions reminiscent of higher-order solitons are 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 true asymmetric N=2 solitons. The introduction of the filter appears to simplify the intracavity shaping mechanisms in such a way that the nonlinear Schrodinger equation becomes a good approximation for pulse generation in the laser. The remarkable stability achieved allows for accurate characterization and control