We are studying the application of an adaptive optics system to upgrade the beam quality of a laser. The adaptive optics (AO) system consists of a bimorph deformable mirror, a Shack-Hartmann sensor and a control system. In most AO applications, the beam aperture is considered to be circular. However, in some cases such as laser beams from unstable resonators, the beam apertures are annulus or a holed-rectangle. In this paper, we investigate how well a bimorph deformable mirror of ${Phi}120;mm$ clear aperture can compensate phase distortions for three different beam configurations; 1) ${Phi}120;mm$ circular aperture, 2) ${Phi}100;mm$ annulus aperture with a ${Phi}20;mm$ hole and 3) $70;mm{ imes}70;mm$ square aperture with a hole of $30;mm{ imes}30;mm$. This study concludes that the bimorph mirror, which might be considered as a modal controller, can compensate tilt, defocus, coma and astigmatism, and spherical aberration for all three beams.