Modelling of the erbium-ytterbium laser

We have developed a modelisation of the Yb:Er glass laser system for pulsed regime. The model is first validated in CW regime with a good agreement with experimental values. The agreement in Q-switch mode is only qualitative. Nevertheless, tendences are outlined due to the particular dynamical behaviour of a codoped system. Especially, we pointed out the possibility of achieving Q-switch operation with pulse repetition frequency greater than the spontaneous de-excitation rate of the erbium upper level without output laser pulse characteristic degradation. On the other hand, gain-switch operation is not well suited for such codoped systems.