Finite-element analysis of single-frequency silica-based Er³⁺-Yb³⁺ co-doped waveguide lasers

Continuous wave laser operations of silica-based Er/sup 3+/-Yb/sup 3+/ co-doped waveguides have been numerically analyzed by means of a finite-element method. The theoretical model, based on propagation-rate equations, describes uniform upconversion by a dipole-dipole interaction between Er/sup 3+/ ions, and includes a pair-induced energy transfer process from Yb/sup 3+/-Er/sup 3+/ Numerical results show that single-frequency operation with slope efficiency higher than 50% and threshold pump powers of few mW can be achieved in short and heavily doped waveguides equipped with input dielectric mirrors and output distributed Bragg reflectors.>