High-Resolution Compact Plasmonic Wavelength Demultiplexers Based on Cascading Square Resonators

A compact high-resolution structure for plasmonic wavelength demultiplexers with cascading square resonators is proposed and demonstrated numerically by using the two-dimensional finite element method. It is found that the full width at half maximum of the transmission spectrum can be narrower (～10 nm) than any results reported before. The simulation results can be explained by the temporal coupled-mode theory. This structure can be easily extended to 1×N channels, which has an important role in the wavelength division multiplexing system in nanoscale.