Analysis of optical impedance matching and polarization matching for integration of surface plasmon polaritons waveguides and dielectric waveguides

초록

We propose an efficient method to integrate a nano-scale surface plasmon polariton (SPP) waveguide (WG) and a dielectric WG by way of achieving the optical impedance matching and polarization matching between the two waveguides. We use a guided wave coupler, or a directional coupler, for the optical impedance matching between two waveguides. For the optical impedance matching, we propose a guided-wave coupler between a silicon WG and a SPP WG. The lightwave entering the silicon WG is transferred to the SPP WG by way of the optical impedance matching. For the polarization matching, we show the polarization dependent excitation of the SPP modes in the single WG and in the metal slot SPP WG. We find that the symmetry of the modal shape in the vertical direction should be supported to couple the two waveguides laterally. We also find that the two fundamental modes in the single metal WG can be excited only by the TM modes, while the two fundamental modes in the metal slot WG can be excited only by the TE modes. The results are useful for application in the nano-scale photonic integration.