Tilted mirror for lateral mode discrimination and higher kink-free power in fiber pump lasers

Beam steering arising from interference between the fundamental lateral mode and higher order lateral modes limits the performance of 980-nm power lasers. In this paper, we analyze the feasibility of using a tilted mirror to discriminate against higher order modes. We calculate the reflectivity seen by different modes as a function of the thickness and tilt angle of the coating. Our results suggest that careful engineering of tilted coated mirrors represents a viable technique for improving the performance of power lasers.