Confinement and Integration Density of Plasmonic Waveguides

In general, plasmonic waveguides exhibit a tradeoff between propagation loss and mode confinement-the smaller the mode size, the higher the propagation loss. We compare the confinement and loss of three commonly used plasmonic waveguides. We define two distinct figures of merit based on application for which the plasmonic waveguide is designed: 1) applications which require high power density and 2) applications which require high lateral packing density. The first figure of merit is based on the power density and propagation loss, whereas the second depends on the coupling length and the propagation loss. We have identified the relative advantages and limitations of the plasmonic waveguides for these different applications.