Design of an integrated coupler for the electrical generation of surface plasmon polaritons.

Recently a surface plasmon polariton (SPP) source based on an electrically operated semiconductor laser has been demonstrated. Here we present a numerical investigation of the light-SPP coupling process involved in the device. The problem consists in the coupling via a diffraction grating between a dielectric waveguide mode - the laser mode - and a SPP mode. The issue of the coupling efficiency is discussed, and the dependence on various geometrical parameters of both the grating and the dielectric waveguide is studied in detail. A maximum coupling efficiency of approximate to 24% is obtained at telecom wavelengths, which could lead to a high-power integrated SPP source when combined to a laser medium. (C) 2011 Optical Society of America