MEMS-based VCSEL beam steering using replicated polymer diffractive lens

Abstract. This paper describes a fully integrated micro-optical system, in which dynamic angular control of the beam from a VCSEL (vertical cavity surface emitting laser) is realized by laterally moving a collimat¬ing diffractive lens in the light path. The lens is mounted on a translatable silicon stage, which consists of a frame with an opening for the light to traverse the lens and electro-statically driven comb actuators, by which the lateral movement is achieved. Devices implementing both 1D and 2D scanning have been fabricated and evaluated. Integration of the lens onto the translatable silicon stage is done using a newly developed fabrication process based on hot embossing of an amorphous fluorocarbon polymer. This fabrication process relies on a reversed-order protocol, where the structuring of the optical element precedes the silicon microstructuring. Assembly and packaging of the VCSEL-MOEMS system, using LTCC (low temperature cofired ceramic) technique, is also demonstrated. Optical evaluation of the system and beam steering function shows significant beam deflection for a relatively low driving voltage (~70 V).