CMOS compatible polarization splitter using hybrid plasmonic waveguide

We design and experimentally demonstrate an ultrashort integrated polarization splitter on silicon-on-insulator (SOI) platform. Our polarization splitter uses a hybrid plasmonic waveguide as the middle waveguide in a three-core arrangement to achieve large birefringence, allowing only transverse-magnetic (TM) polarized light to directionally couple to the cross port of the directional coupler. Finite-difference time-domain (FDTD) and eigenmode expansive (EME) calculations show that the splitter can achieve an extinction ratio of greater than 15 dB with less than 0.5 dB insertion losses. The polarization splitter was fabricated on SOI platform using standard complementary metal-oxide-semiconductor (CMOS) technology and measured at telecommunications wavelengths. Extinction ratios of 12.3 dB and 13.9 dB for the transverse-electric (TE) and TM polarizations were obtained, together with insertion losses of 2.8 dB and 6.0 dB.