Comparative study of the integration density for passive linear planar light-wave circuits based on three different kinds of nanophotonic waveguide

A theoretical analysis and comparison of the integration density are given for passive planar lightwave circuits based on three different kinds of nanophotonic waveguide, namely, photonic crystal waveguides, Si nanowire waveguides, and nanoslot waveguides. Two criteria for determining the integration density are used. One is the minimal decoupled separation between two parallel nanophotonic waveguides, and the other is the area occupied by a low-loss 90 degree turn. Some important functional components (such as Y branches and optical add-drop filters) are also chosen as basic elements to evaluate the integration density. It is shown that the integration densities of passive linear planar lightwave circuits based on these three kinds of nanophotonic waveguide are comparable.