Optimization of strongly pumped Yb-doped double-clad fiber lasers using a wide-scope approximate analytical model

• We introduced a precise analytical solution for strongly pumped Yb-doped DCFLs.
• The maximum relative error between our model and the numerical result is 2.72%.
• We studied the influence of most affecting parameters on the fiber laser performance.
• We introduced a simple optimization method depending on our analytical model.
• Our model gives a physical comprehension for the changes of the signal power along the fiber.

An analytical model based on the rate equations of strongly pumped Yb-doped double-clad fiber laser (DCFLs) is presented. The output power and the distributed laser along the whole fiber have been found. In this paper, most parameters affecting the laser performance have been considered. The influences of scattering losses, pump reflection, output reflectivity, doping concentration and fiber length have been studied. It is shown that for wide ranges of the previous parameters and large variations of the input powers for all types of pumping (forward, backward and two-end), the maximum relative error of the output power would be less than 2.72% when the results are compared with the numerical model. Depending on our analytical model, a simple optimization method has been illustrated for high-power laser oscillators.