Theoretical investigation of optimal propagation performance in multilayer long-range surface plasmon waveguide

A theoretical study of a long-range surface plasmon waveguide is reported. The proposed waveguide has a similar configuration to the widely employed Insulator-Metal-Insulator (IMI) structure. Propagation performance with respect to propagation distance and mode confinement are investigated. As a result, the effect of an additional intermediate dielectric layer to the long-range plasmonic waveguide is discussed. Finally, optical gain is proposed as a practical solution to resolve the tradeoff between propagation loss and mode confinement.