Nanoplasmonic triple-wavelength demultiplexers in two-dimensional metallic waveguides

A novel kind of plasmonic wavelength demultiplexers (WDMs) based on two-dimensional metal–insulator–metal waveguides with side coupled nanocavities (SCNCs) is proposed and numerically investigated. The WDMs contain three waveguide output channels, each of which functions as a dual-stopband plasmonic filter. The demultiplexing wavelengths can be tuned by controlling the lengths and widths of SCNCs. The finite-difference time-domain results can be accurately analyzed by the resonant theory of nanocavity. Our structures have important potential applications for design of WDM systems in highly integrated optical circuits