Design of active lens for VCSEL collimation

Active control of VCSELs beam properties is a key issue to improve their integration in microsystems. We have designed a micro-optical system that allows for a dynamic displacement of the VCSEL beam. It consists of a polymer microlens associated to a SU-8 membrane vertically moved by means of a thermal actuator. This approach is suitable with laser sources arrays. We present results on optical design demonstrating that a small deflection of the membrane (2μm) could lead to a large displacement of the beam waist vertical position (in the millimetric range). Thermomechanical modelling is performed to evaluate the maximum membrane displacement achievable with this system. Finally, first feasibility results are presented.