High Efficiency Broadband Polarization Converter Based on Tapered Slot Waveguide

A novel high efficiency broadband polarization converter based on an adiabatic tapered vertical slot waveguide is proposed and analyzed. Unlike previously reported tapered polarization converters, this device converts the first-order TM/TE mode into the first-order TE/TM mode. The structure utilizes a vertical slot waveguide, which only needs a one-mask etching process. The bandwidth is ultrawide, ~100 nm (1500-1600 nm) with a conversion efficiency of > 98%. The total length of the polarization converter is 116 μm, and its minimum fabrication tolerance is acceptable for modern nanofabrication technology.