In the astrophysical context of the search for Earth-like extrasolar planets, an important research effort has been done for the realization of single-mode integrated optics devices for mid-infrared space-based interferometry. Preparatory projects like FKSI , where rejection of high order modes is required to a level better than 40dB, will need photonic devices that achieve modal filtering and beam combination in the mid-IR band. In this context, we present results on midinfrared planar integrated optic beam combiners characterized at LAOG using chalcogenide and silver halide materials. We show results on FTS measurements, allowing to determine the single mode spectral domain, as well as interference fringes obtained from Y-junctions realized on these materials.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.