The influence of an optical well in controlling the mode splitting in a photonic molecule

In this paper we investigate the mode splitting in a photonic molecule consisting of two coupled photonic crystal cavities separated by an optical well in a photonic crystal waveguide. We show experimentally, by using a confocal microphotoluminescence mapping technique, that fine control of the coupling between the cavities can be achieved by the addition of an optical well. Our results demonstrate that an increase in the depth of the well leads to an increased mode splitting and a strongly red shifted symmetric supermode (the ground mode).