A silicon-based polarization rotator (PR) for cross-slot waveguides is proposed and analyzed. The rotation region of the PR is formed by removing one of the silicon wires from a cross-slot waveguide, resulting in a strong hybridity for the lowest eigenmodes. As a result, the TE (TM) polarization can be rotated efficiently to the TM (TE) polarization at a length of 18.9 mu m. The results show that the extinction ratio (ER) (insertion loss) is 31.6 (0.37) dB for TE-to-TM mode and 31.9 (0.37) dB for TM-to-TE mode. Moreover, a wide bandwidth of similar to 230 nm for both polarizations is obtained for keeping the ER over 20 dB. In addition, fabrication tolerances to the structural parameters are investigated, and field evolution along the propagation distance is also presented. (C) 2015 Optical Society of America
展开▼
