Plasmonic waveguide directional coupler based on two dimensional two-hole coupler

In this paper, we propose, analyze and simulate the performance of a plasmonic directional coupler in two dimensional plasmonic waveguides using the numerical method of finite difference time domain (FDTD). The directional property of the directional coupler is produced through the use of two separate wave components, which add in phase at the coupled port and are cancelled at the isolated port. The simulation results are in good agreement with the analytic considerations.