The effect of pair-induced energy transfer on the performance ofsilica waveguide amplifiers with high Er3+/Yb3+concentrations

High-concentration Er³⁺/Yb³⁺ co-doped silica waveguide amplifiers are numerically analyzed. With optimized rare-earth concentrations the effect of Er³⁺/Er³⁺ ion-pairs can be neglected and each Er³⁺ ion can be assumed to be paired only to the surrounding Yb³⁺ ions. The rate-equations model includes uniform upconversion mechanisms from ⁴I_13/2 and ⁴I_11/2 erbium levels and an Yb³⁺ to Er³⁺ 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