Population dynamics in Yb:Er:phosphate glass under neodymium laser pumping

Characteristics of ytterbium to erbium energy transfer in Yb:Er:phosphate glasses have been studied for a case when Nd phosphate glass laser is used as a pumping source. A theoretical model of the energy transfer was developed to reproduce the experimentally observed population dynamics of the Er/sup 3+/ upper and lower laser levels. The results show that saturation and frequency hole burning of the inhomogeneously broadened Yb/sup 3+/ absorption line are of primary importance in determining the dynamics and efficiency of the Yb/sup 3+/-Er/sup 3+/ energy transfer under Nd laser pumping. The influence of other loss channels that have been identified in previous studies is found to be relatively small. The model also yields the lifetime of the frequency hole, as well as the effective rates of energy transfer between groups of Yb/sup 3+/ and Er/sup 3+/ ions in phosphate glasses.>