Routing and steering of optical beams in guiding structures is an attracting function, especially for the realization of inter-chip and intra-chip optical dynamic interconnections. Several physical mechanisms were used, in a huge variety of materials and device configuration. In this paper we propose a simple solution that allows efficient beam steering in a PMMA/PUR/PMMA slab waveguide, by means of thermal control. The operation principle is based on the generation of a 2D temperature distribution field in the slab waveguide cross section, which induces lateral confinement for the propagating optical radiation. In particular, the choice for core and cladding fabrication, of materials characterized by negative thermo-optic coefficient, allows to push away the optical beam from the hottest region and control the spatial position by tuning the temperature difference between hot and cold electrode. In this way, it is possible …