There has been recent interest in Diode Pumped Alkali Lasers (DPALs) and their scaling to higher powers. Scaling of DPALs to high powers requires using multiple pump sources such as laser diode arrays or stacks of arrays. Coupling of multiple pump beams into the laser gain medium can be realized using a transverse pumping scheme that is most efficient for the laser operating with large mode volume. We have demonstrated Cs laser with unstable resonator transversely pumped by 15 narrowband diode laser arrays. This laser operates on lowest transverse mode with a diameter of 7 mm with an optical-to-optical efficiency higher than 30%. An alternative power scaling approach: Master Oscillator and power Amplifier (MOPA) system with transversely pumped by multiple diode lasers Cs amplifier was studied experimentally and demonstrated high optical efficiency.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.