Investigation of light coupling between a semiconductor nanowire and a plasmonic waveguide

We report a theoretical investigation of light coupling between a semiconductor nanowire (NW) and a plasmonic waveguide. The light emitted from the NW is coupled to the waveguide and excites a symmetric plasmonic waveguide mode propagating along the top surface of the waveguide. Using numerical simulations, coupling efficiencies were calculated for various coupling structures consisting of tapered/non-tapered NWs and single-strip/double-strip gold waveguides. The highest coupling efficiency of >2.8% was obtained between a tapered NW and a double-strip plasmonic waveguide with a height of 200 nm. This study offers a new opportunity for the efficient integration of nanoscale light sources with plasmonic waveguides and enables further miniaturization of ultracompact photonic integrated circuits.