Coupling between second-order mode in dielectric waveguide and fundamental mode in long range surface plasmon waveguide

The coupling between long range surface plasmon polariton (LRSPP) waveguide mode and dielectric waveguide second-order mode has been studied theoretically and experimentally. It is demonstrated that an almost pure TM-polarized second-order mode of dielectric waveguide is excited efficiently by the LRSPP fundamental mode. The proposed hybrid coupler inspires a new way for generating high-order waveguide modes, especially the high-order SPP waveguide modes, which is promising for mode division multiplexing, bio/chemical sensing, photonic circuits and other optical applications.