Compact Bidirectional Metallic-Dielectric-Air Polarization Splitter Based on a Cascaded Grating

A compact bidirectional polarization splitter based on two cascaded sub-gratings in a metallic-dielectric-air (MDA) waveguide is proposed and theoretically analyzed. The normally incident beam coupled to the MDA waveguide is split into left-going TE- and right-going TM-polarized modes by the structure. The operation principle is clarified and a coupled-mode model is developed for facilitating design. The polarization extinction ratio better than 33 dB and crosstalk less than -41 dB for TE-polarized mode and the corresponding 36 and -28 dB for TM-polarized mode are achieved at the operating wavelength 850 nm.