Laser Guide Star (LGS) is essential in adaptive optics system for ground-based astronomical observation. This dissertation presents the implementation of membrane external-cavity surface-emitting laser (MECSEL) as a compact and cost-effective LGS platform. The MECSEL gain chips employ multi-quantum-well structure with In0.38Ga0.62As quantum wells, GaAs barriers, GaAs0.94P0.06 strain compensation layers, and In0.49Ga0.51P window layers. The laser cavity configurations, including linear, V-shaped, and Z-shaped geometries, were analyzed through both numerical simulations and experimental investigations. An in-well pumping method was explored to reduce quantum defect, addressing the thermal rollover limitation for high power output. A comparative study between barrier pumping and in-well pumping demonstrated the superior performance of the in-well method in terms of slope efficiency and maximum output power. New multi-pass pumping structures were designed using Zemax modeling, with two specific configurations experimentally realized in MECSELs. A hybrid-MECSEL (H-MECSEL) design was introduced to simplify multi-pass pumping while enhancing thermal management. COMSOL modeling was employed to assess thermal management capabilities, and the thermal lensing within the H-MECSEL gain chip was studied for optimized laser cavity design.