Efficient 4 and 8 plasmonic wavelength DEMUX with ultra high Q-factor and low FWHM based on nano-rectangular resonators

A novel plasmonic DEMUX with four and eight channel outputs has been designed using rectangular resonators coupled with a metal-insulator-metal plasmonic waveguide. By setting the output port to the side of the rectangular resonator, the required wavelength can be extracted from the wavelength combination. The wavelength obtained at the output ports depends on the width of the rectangular resonators. The proposed structures use silver and air as metal and insulator layers, respectively. The silver's permittivity is characterized by the Drude model. The finite element method was used for the numerical investigation of the proposed structures. A single-mode filter is the basic plasmonic filter used in the design of plasmonic DEMUXs. The results show that our proposed DEMUXs have a Q-factor of 81.08 and 101.93 in average for the 4 and 8 output channels respectively with low FWHM of 9.625 nm and 8.9 nm respectively. Taking into account the number of outputs (considering an eight-channel outputs) and the compatible sizes of the proposed DEMUXs, they can be used in integrated optical circuits for communication purposes.