测试了应用于神光Ⅱ系列装置93片N31型钕玻璃的小信号增益系数。结果表明，Nd2O3质量分数为2.2%的钕玻璃平均小信号增益系数为0.0387 cm-1，Nd2O3质量分数为3.0%的钕玻璃平均小信号增益系数为0.0416 cm-1，两种浓度的钕玻璃不同样品间小信号增益系数的起伏范围分别为0.86%和0.76%。根据所测定的增益值，表明N31型钕玻璃的增益起伏符合神光Ⅱ系列装置要求，为实现该装置中每一路增益性能的平衡提供了有力保障，也为今后对更大尺寸钕玻璃增益性质的控制提供了经验。

The energy transfer and cooperation upconversion processes are investigated in Yb³⁺/Er³⁺ 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 Yb³⁺ to Er³⁺ as well as the cooperation upconversion coe±cient C_up from ⁴I_13/2 of Er³⁺. The fitted k and C_up 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 Yb³⁺/Er³⁺codoped laser glass.