Analysis of polarization characteristics based on asymmetric metal-clad optical waveguides with buffer layer

We propose a plasmonics-based optical polarization rotator. The proposed device is designed using skewing phenomena of propagation waves at the slotted waveguide with metal film by 3D-FDTD method. 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. We have overcome the high propagation loss of metal-clad structures by using a buffer layer. The length of designed polarization rotator is just 5 μm for 90% polarization rotation ratio.