理论分析了激活介质热效应对端面泵浦固体激光器激光振荡模式分布的影响，并以光纤耦合半导体激光器端面泵浦Nd∶YAG激光器实验研究了激活介质热效应对激光振荡模式的影响。实验结果表明：由于热效应，基模的模体积随泵浦功率的增加而变大，基模在模式竞争中占优；在泵浦光轴线偏离几何腔轴时，基模光斑中心位置朝泵浦光轴线所在位置移动，偏离量与泵浦光轴线的偏离量近似成线性关系。利用实验结果指导腔调节，可使泵浦光轴线与几何腔轴精确重合，获得了椭圆率为0.98、M2因子为1.01的基模输出。

The influence of the thermal effect of the active medium on the laser oscillating modes distribution of end-pumped solid-state lasers is theoretically analyzed. With the fiber coupled diode lasers which end-pump the Nd∶YAG laser, the influence of the thermal effect on laser oscillating modes was studied. It proves that TEM00 mode volume becomes larger when the pumping power increases，and TEM00 mode becomes dominant in the mode competition. As the pumping beam departures from the geometry cavity axis, the light spot center of TEM00 mode moves to the axis of the pumping beam and the quantity of the beam wandering becomes linear with that of the pumping beam axis. The results of the experiment agree with the theory.TEM00 mode output in which the ellipticity is 0.98 and M2 is 1.01 was obtained.