Experimental characterization of directional couplers in InP photonic membranes on silicon (IMOS)

We experimentally study the performance of directional couplers fabricated in indium-phosphide membrane on silicon (IMOS) technology. We both investigate the validity of the coupled mode theory (CMT) applied to directional coupler structures with high index contrast and study the effect of some different topological choices in device fabrication. In particular, besides the conventional curved structures, we consider ultra sharp corner bends that reduce the footprint. The effect of fabrication tolerances on the different guided mode polarizations is also discussed.