The scope of presented work was focused on laser diode optics destined to end pumped solid state lasers. The background and idea of quasi geometrical approach to laser beam propagation in real optical systems were presented. The criterion of laser optics quality based on concept of M2 parameter was proposed and discussed. The appropriate software destined to evaluate laser beam propagation in real optical systems was developed. The results of computations were compared with results of intensity distributions measurements in the caustics regions for a few practically realized cases.