提出了一种新型激光谐振腔，即“非稳腔稳腔耦合谐振腔”，其中心部分呈现出非稳定谐振腔结构，边缘部分呈现出稳定谐振腔结构。用Fox-Li的方法，模拟计算非稳腔稳腔耦合谐振腔的基横模。优化出腔长1.2 m的密封CO2激光器的谐振腔参数。数值分析结果表明，与稳定谐振腔相比较，其基横模的输出功率可提高约2倍，而聚焦中心光斑输出功率可增加约1.5倍。最后设计了另一种用具有球差的球面透镜与球面反射镜实现的非稳腔稳腔耦合谐振腔。

A novel optical resonator is proposed, so called unstable-stable coupling resonator, whose central portion acts as unstable resonator and edge portion acts approximately as stable resonator. Using Fox-Li method, the fundamental transverse modes of unstable-stable coupling resonator are computed. An optimization of the unstable-stable coupling resonator is given for a sealed-off CO2 laser with length of 1.2 m. Results show that output power of fundamental transverse mode can be increased about 2 times and central core output power on the focus plane can be increased about 1.5 times in comparison to stable resonators. And a design of unstable-stable coupling resonator is presented, which consists of a plat mirror, a spherical lens with aberration and a spherical mirror with aberration.