Novel analytical model for nano-coupler between metal-insulator-metal plasmonic and dielectric slab waveguides

摘要

We propose a new analytical model for nano-coupler between metal-insulator-metal (MIM) plasmonic and dielectric slab waveguides. By using the boundary conditions and mode matching technique, the analytical expression for transmission coefficient can be achieved at the plasmonic-dielectric junction. The theoretical results are compared with the simulation results of COMSOL software. A good agreement between the simulation and theoretical results is observed which validates our analytical model. The maximum transmission efficiency of the coupler can be obtained by changing the width of the dielectric (W-d) and air (W-a) layers. For the nano-coupler with W-d=300nm at the wavelength 1.55m, the results show that maximum transmission efficiency of 75% can be achieved at the width of 63nm (W-a=63nm). Our analytical model is accurate and can calculate the modal properties of the proposed coupler.