Compact polarization rotator based on slotted optical waveguide with buffer layer using surface plasmon polariton

Abstract

A novel polarization rotator with asymmetric optical waveguide based on plasmonics is proposed and analyzed for the first time. The polarization rotator using skewing effects at the slotted optical waveguide (SOW) with metal film was designed by 3D-FDTD method. A metal film on the waveguide acts to rapidly rotate the optical polarization, because the plasmonic characteristics of a metal film can induce the slow group velocity through the metal-clad optical waveguide. Here, the optical waveguide with a buffer layer is proposed to reduce the propagation loss. The polarization rotator length of 6 μm is among the shortest reported in the waveguide-type polarization rotators. The polarization conversion efficiency of 98.93 % is observed near 1550 nm along with a propagation loss of -0.43 dB. The proposed structure is smaller than previous polarization rotator with asymmetric optical waveguide and is more effective to control polarizations using by plasmonic effects.