<p>Numerical optimization of antenna elements to be employed in a large-scale two dimensional silicon-based optical phased array.</p><p>Financial support from the German Research Foundation (Deutsche Forschungsgemeinschaft DFG, project 231447078–TRR 142, subproject B06 & C05) and Ministry of Culture and Science of the state of North Rhine-Westphalia (PhoQC project) is gratefully acknowledged.</p>