Multiple Wavelength-Channels in SPP Waveguides for Optical Communication

Surface plasmon polaritons （SPPs） can be excited, meanwhile some peculiar optical phenomena will appear when light irradiates metal structures under some conditions. Based on photonie band gap theory, in this Letter we present a kind of SPP waveguide with multiple wavelength-channels. By using the Bragg effect and introducing some geometric defect layers into a quasi-periodic metal heterowaveguide, the multiple SPP forbidden bands （SPFBs） in a given waveband can be generated, and the multiple SPP pass bands （SPPBs） with narrow bandwidth in each SPFB can be realized. The SPP propagation in metal heterowaveguide is calculated by FDTD and transfer matrix methods. By selecting appropriate thickness, position and the number of defect layers, two SPPBs can be achieved in the SPFBs around 1.31 and 1.55μm simultaneously.