Gain saturation and pump depletion in high-efficiency distributed-feedback rare-earth-doped lasers.

We propose a model for designing and analyzing rare-earth-doped distributed-feedback (DFB) lasers. The effects of pump depletion and cross-gain saturation are included and shown to be significant for high-efficiency lasers. Our simulations show good agreement with experimental data from an ytterbium-doped fiber laser. We also give some design guidelines for DFB fiber lasers.