报道了一种高平均功率的脉冲Nd:YAG激光器。对四棒振荡两棒放大的主振荡功率放大器（MOPA）结构中晶体棒的失调角度允许范围进行了理论分析，并与六棒串接谐振腔结构中晶体棒失调角度允许范围进行比较。由比较结果可知，MOPA结构降低了晶体棒的串接精度要求，在相同的失调角度下，光轴的变化量小于腔内多棒串接谐振腔，有利于提高多棒脉冲激光器的安全性能，实现高平均功率、高脉冲能量输出。实验中激光器采用四棒振荡两棒放大结构，调整每根晶体棒的失调角度到允许范围内，在输入电功率87 kW，占空比17%时，最高输出平均功率为3011 W，峰值功率17.7 kW，最高单脉冲能量为67 J，光束参数乘积为25.2 mm·mrad。电光转换效率3.46%，长时间工作不稳定度小于2%。

A pulsed Nd:YAG laser with high average power is presented. The influence of offset angle of rods in six rods series connection resonator and the master oscillator power-amplifier (MOPA) system consisting of four rods oscillator and two rods amplifier are investigated theoretically. And the tolerances of offset angle are compared. It can be seen from the investigation results that MOPA system reduces the requirement of precision of series connection. With the same offset angle, the deviation of optical axis of the MOPA system is less than that of six rods resonator. It is helpful to improve the security performance of multi-rod pulsed laser, and obtain high average output power and high pulse energy. A MOPA system with four rods oscillator and two rods amplifier has been used in the experiment, and the offset angle of all rods is adjusted in the tolerance. With input electric power of 87 kW and a duty cycle of 17%, a maximum average output power of 3011 W, a peak power of 17.7 kW, a maximum single pulse energy of 67 J and a beam parameters product of 25.2 mm·mrad have been obtained. The electro-optical conversion efficiency is 3.46%, and instability of the laser is less than 2%.