Plasmonic-Assisted Polarization Beam Splitter Based on Bent Directional Coupling

A plasmonic-assisted polarization beam splitter based on bent directional coupling is proposed. The phasematch condition is satisfied for TM polarization only by properly choosing the widths of the two waveguides. Due to the bent and plasmonic-assisted asymmetry, birefringence is greatly enhanced, which allows high extinction ratio for polarization beam splitting with the total footprint of 8.1 μm×2.6 μm. At the wavelength of 1.55 μm, the extinction ratios are 25.2 and 29.5 dB for TM and TE polarizations, respectively and the corresponding insertion losses are only 0.2 and 0.035 dB.