A numerical model based on ray optics formulation taking the optical path length into account. was described and applied to numerical investigations on athermal birefringence compensation scheme proposed and experimentally demonstrated by Q. Lu et al. [Opt. Quantum Electron. 28 (1996) 57]. Taking into consideration the thermal lensing effects of laser rods depolarization Losses and spatial intensity profiles of depolarized beams were calculated for the scheme. It was theoretically confirmed that using a polarization rotator and imaging optics effective compensation for the birefringence in rods is possible for a wide range of pumping power.