Wavelength filtering and demultiplexing devices based on ultrathin corrugated MIM waveguides

Abstract

We have numerically investigated the transmission properties of spoof surface plasmon polaritons on the ultrathin corrugated metal–insulator–metal (MIM) waveguides with different grooves. A band-pass plasmonic filter with T-shaped grooves and a compact 4-way wavelength division demultiplexing (WDM) incorporating the filter have been proposed. The whole 4-way WDM is more compact by the use of corrugated MIM waveguides with meander grooves. The near electric field distributions show that electromagnetic waves at different frequencies are guided and propagate along different branches with good isolation between branches. The experimental and numerical results have shown good agreements and validated the functions of the 4-way wavelength splitter. We also numerically investigate the 4-way WDM at terahertz frequencies by scaling down the whole structure. It is believed that the spoof plasmonic devices can find more applications in the plasmonic integration platform, such as optical communications, signal processing and spectral engineering.