General model for a multimode Nd-doped fiber laser. II: Steady-state analysis of length-dependent polarization effects

We present a steady-state analysis of a general model for a bipolarized Nd- doped fiber laser including the slow longitudinal variations of the dynamic al variables. The combined effects of pump-induced, distributed, and locali zed anisotropies are studied versus the fiber length. In particular, the ev olution of the thresholds versus the pump-input polarization angle, for dif ferent fiber lengths, is investigated in depth. Approximate analytical resu lts are derived for the thresholds and the output intensities. A good agree ment with the numerical simulations is achieved in a large range of paramet ers.