We investigate beam shaping in broad area semiconductor amplifiers
induced by a periodic modulation of the pump on a scale of several microns.
The study is performed by solving numerically a (2+1)-dimensional model for
the semiconductor amplifier. We show that, under realistic conditions, the
anisotropic gain induced by the pump periodicity can show narrow angular
profile of enhanced gain of less than one degree, providing an intrinsic
filtering mechanism and eventually improving the spatial beam quality.
