An analytical approach for the thermal design of high-power-fiber laser components is presented. The modular structure
of the model allows adaption to different fiber designs and gives insight into the governing parameters of the heat
transport. Furthermore the analysis and analytic optimization of interacting effects of groups of layers is possible with
this method and is presented in this work. A previously suggested cooling scheme for a heat load of 120 W/m is
analyzed. Applying the analysis to air-clad-fibers is leading to results differing up 40 % from previous works. The FEM-analysis
of the cooling of splices shows that the cooling scheme suggested for the active fiber is not sufficient for splices
for a fiber resonator in the kW-range. Using a one-dimensional model it can be shown that if a small percentage of loss
in the splice is absorbed inside the recoat, it is necessary to reduce the recoat thickness.