Optimization of strongly pumped fiber lasers

Backreflection of the residual pump power into the cavity, and optimization of the fiber length, may significantly improve the efficiency of a strongl y pumped fiber laser. A rate equation model is introduced and studied. Exam ples for Yb3(+)-doped fiber lasers, with DBR mirrors at either end, show th at employing such a geometry results in higher efficiency with shorter opti mal fiber length. Approximate analytical and quasi-analytical expressions a re shown to be in excellent agreement with the exact numerical solution of the rate equations.