Compact Polarization Rotator Based on Surface Plasmon Polariton With Low Insertion Loss

An ultracompact mode-evolution-based polarization rotator is proposed. The polarization rotator consists of silicon wire waveguide covered by silica buffer layer and linearly tapered thin aluminum. Numerical simulations using 3-D finite element method demonstrate that it is possible to obtain an 11-μm-long polarization rotator with about -20-dB extinction ratio and less than 4.7-dB loss in C-band for both polarization conversions from TM-like mode to TE-like mode and from TE-like mode to TM-like mode.