Fluctuations and Chirp in Colliding Pulse Mode-Locked Dye Lasers

To ensure the shortest possible pulse duration in passively mode-locked dye lasers intracavity self-phase modulation (SPM) and phase dispersion (PD) must be properly balanced /1,2/. SPM is caused mainly by time-dependent saturation of the bleachable absorber /3/, and also by the Kerr-type nonlinearity of the index of refraction of the dye solvent. So far very little attention has been paid to the interrelation between SPM an PD effects and the noise properties of the pulses. We believe that consideration of pulse fluctuations is essential because in almost any conceivable application the noise of the pulses will be a matter of concern. Also the noise behavior provides interesting insight into the pulse forming and pulse evolution mechanisms.