Numerical analysis and experimental results of output characteristics for strongly pumped Yb3+-doped double-clad fiber laser

The output characteristics of strongly end-pumped Yb3+-doped double-clad fiber lasers with linear cavity are studied in theories and experiments. Based on the rate equations of fiber lasers, the distributions of pump light and laser power along the DCF fiber, the relations of output power with pump power, as well as the effects of fiber length and cavity reflectivity on output power are got by means of numerical analysis. The maximum cw output power of 10.6 W and slope efficiency of 86% is obtained by the Yb3+-doped D-shaped double-clad fiber laser in experiments. With different output couplers, the output power, threshold pump power and slope efficiencies of the fiber laser were measured. Experimental results are coincident with theoretical analysis very well. It will be helpful for scaling the power of fiber lasers in theories and experiments.