Energy-transfer efficiency in Er/Yb-codoped phosphate waveguides in dynamic regime

A power function dependence of the Yb Er energy-transfer coefficient on the input pump power offers a good agreement between experimental and numerical results for the decay constant of the copropagating amplified spontaneous emission in an Er/Yb-codoped phosphate waveguide amplifier. The assumed dependence is obtained from the results of the statistical averaging of energy-transfer interactions on a microscopic level.