Nonstationary pulse regimes associated with self modulation of a Kerr-lensmodelocked Ti:sapphire laser have been studied experimentally andtheoretically. Such laser regimes occur at an intracavity group delaydispersion that is smaller or larger than what is required for stablemodelocking and exhibit modulation in pulse amplitude and spectra atfrequencies of several hundred kHz. Stabilization of such modulations, leadingto an increase in the pulse peak power by a factor of ten, were accomplished byweakly modulating the pump laser with the self-modulation frequency. The mainexperimental observations can be explained with a round trip model of the fslaser taking into account gain saturation, Kerr lensing, and second- andthird-order dispersion.
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