The effect of pair-induced energy transfer on the performance of silica waveguide amplifiers with high Er/sup 3+//Yb/sup 3+/ concentrations

High-concentration Er/sup 3+//Yb/sup 3+/ co-doped silica waveguide amplifiers are numerically analyzed. With optimized rare-earth concentrations the effect of Er/sup 3+//Er/sup 3+/ ion-pairs can be neglected and each Er/sup 3+/ ion can be assumed to be paired only to the surrounding Yb/sup 3+/ ions. The rate-equations model includes uniform upconversion mechanisms from /sup 4/I/sub 13/2/ and /sup 4/I/sub 11/2/ erbium levels and an Yb/sup 3+/ to Er/sup 3+/ pair-induced energy transfer process. Numerical results demonstrate the possibility of fabricating short- and high-gain integrated optical amplifiers; it is shown that net gain as high as 3 dB/cm can be obtained.<>