PULSE RESHAPING IN ACTIVELY MODE-LOCKED SOLID-STATE LASERS UNDER MONOCHROMATIC INJECTION

We have investigated how the temporal profile and spectral content of the short pulse circulating in the cavity of an actively mode-locked l aser are influenced by the injection of an external monochromatic sign al. We have solved the coupled-mode equations using an iterative appro ach. When the frequency of the injected signal is tuned to the center of the gain line, the pulse can be stretched. Our analysis predicts th at the duration of the short pulse can be reduced by up to 40% when th e frequency of the injected signal is detuned from the center of the g ain line and when its intensity is adjusted to a proper level. At larg er detunings, a periodic beat signal can be generated due to the split ting of the laser spectrum into two components. (C) 1997 Published by Elsevier Science B.V.