Improved Models for Plasmonic Waveguide Splitters and Demultiplexers at the Telecommunication Wavelengths

Single output channel selective plasmonic filter structure based on a nanocavity is proposed and numerically simulated by using the finite difference time domain method with perfectly matched layer absorbing boundary condition. The required filtered wavelength can be obtained by selecting an appropriate length of the nanocavity. Nanocavity model and gain model are introduced and analyzed. Two output channels structure based on two nanocavities is proposed to design a subwavelength plasmonic splitter and demultiplexer operating around 1310 nm and 1550 nm. The finite-difference time-domain (FDTD) simulation results reveal that this new structure is suitable for wideband wavelengths demultiplexing. Finally, we propose a multiwavelength demultiplexing structure based on multinanocavity connected to the bus waveguide.