Three-dimensional gap plasmon power splitters suitable for photonic integrated circuits

In this paper we have investigated the performance of a nano-optical power splitter based on gap plasmon waveguides. The structure consists of the rectangular gap plasmon waveguides in metal films. It is clear that the wave number and correspondingly light confinement and the loss in the waveguides are the most effective parameters in power splitting, but as we know coupling length is another important factor which should be considered. Some dependencies of the coupling length and the maximum transfer power on the structure parameters are studied. It has been shown that approximately 43% transfer power for each arm of the splitter is achievable. Simulation results have been obtained by the compact finite-difference time-domain method. The considered structures, because of their small coupling length and dimensions are appropriate for implementation in photonic integrated circuits.