In this paper, we discuss the design, fabrication, and characterization of electro-thermally-actuated polymer-based micro-optical electro-mechanical microsystems (MOEMS) for active microoptics in VCSEL devices. We describe in particular the principle of a SU8-based MOEMS designed for single-mode VCSEL beam active focusing. The ultimate objective is the realization of parallel compact optical scanners for sensing applications using collective and low-cost technologies. After discussing the advantages of the epoxy resist SU-8 for fabricating an integrated movable lens on active optical devices, we present our latest advances in technology for ensuring precise MOEMS fabrication on small III-V samples and for achieving accurate alignment of lenses on suspended circular membranes. Finally, we present our first results on the beam focusing of multimode VCSELs, which demonstrate the feasibility of our approach and could provide new insights in the MEMS-VCSEL field.