We consider the modelling and design of high power ZBLAN glass based erbium (III) doped fibre lasers operating in the Q-switched regime. The detailed description of all models used is given. The results are calculated for a standard set of modelling parameters used in the literature, which correspond to a commercially available erbium doped ZBLAN fibre.
We apply a time domain method which uses a steady state model to obtain the approximation of the initial conditions and study the dependence of the pulse shape on laser operating parameters.