Polarization characteristics of plasmonics-based optical waveguides for polarization rotation

Abstract

In this paper, we propose a plasmonics-based optical polarization rotator. The proposed structure consists of a slotted waveguide and a metal film. The proposed device is designed using skewing phenomena of propagation waves at the slotted waveguide with metal film by 3D-FDTD method. We have analyzed various structures such as a slotted waveguide, a metal-clad optical waveguide, and a metal-clad optical waveguide with buffer layers. A metal film on the waveguide acts to rapidly rotate the optical polarization, because it has characteristics of slow group velocity according to the metal-clad optical waveguide. Therefore, an ultra-small sized polarization rotator can be realized by the plasmonics-based asymmetric cross sections of waveguides. The length of designed polarization rotator is just 5 μm for 80% polarization rotation ratio.