放大自发辐射（ASE）是影响钕玻璃大口径片状放大器增益性能的重要因素。通过测试钕玻璃大口径片状放大器在不同抽运条件下的增益性能，研究了ASE效应对增益系数和增益分布均匀性的影响，并利用实验数据推算出ASE效应造成的增益系数降低比例。随着抽运能量的增加，ASE效应造成的增益分布塌边、平均增益降低愈发明显。该研究为国产大口径钕玻璃片状放大器的优化设计提供了实验支撑。

Amplified spontaneous emission (ASE) is a key issue which affects the gain of large-aperture Ndglass slab amplifiers. Gain measurement experiments under different pump conditions are carried out to study the effect of ASE on gain coefficients and gain distributions. The gain coefficient derating ratio caused by ASE is calculated based on the experimental data. The results show that the gain turning-down and the decrease of average gain becomes notable as the pump energy increases. The study provides experimental support for further optimization of home-made large-aperture slab amplifiers.