Wavelength filtering and demultiplexing structure based on aperture-coupled plasmonic slot cavities

Abstract

We propose a submicron plasmonic wavelength filtering/demultiplexing structure based on aperture-coupled slot cavities, which can overcome the limitation by the field skin depth of ∼25 nm in a conventional evanescent-coupling approach, and thus lead to an easy-to-fabricate device structure. By introducing the stub-induced interference arm in the drop or bus waveguide, the power ratio between the different resonance modes can be effectively adjusted by changing the stub length. Also, the transmission peak can be about two times higher than that without stub structure in the bus waveguide. Our results open a way to construct nanoscale wavelength filters and demultiplexers for high-density nanoplasmonic integration circuits.