Determination of energy transfer and upconversion constants for Yb3+/Er3+ codoped phosphate glass

The energy transfer and cooperation upconversion processes are investigated in Yb;/Er;codoped phosphate glass.Based on the measured curves of output power versus incident power,the laser and spectroscopic parameters of the glass are fitted and analyzed.We focus on the resonant energy transfer constant k from Yb;to Er;as well as the cooperation upconversion coefficient C;from;I;of Er;.The fitted k and C;can give almost the same results for different thicknesses of glass disk with the same doping concentrations.The determination of these parameters is helpful for the development of Yb;/Er;codoped laser glass.