Hybrid plasmonic polarization splitter using three-waveguide directional coupler in InGaAsP/InP

摘要

We investigated a polarization beam splitter based on a three-waveguides directional coupler by utilizing a hybrid plasmonic waveguide as the middle waveguide. The structure of the proposed polarization splitter is compatible to the InP based conventional waveguide. So, it has the capability of monolithic integration with InP-based active (lasers and photodetectors) and passive components. Polarization splitting is obtained by optimizing the coupling length, the InP-cladding layer thickness, and the gap between straight waveguides. Calculations show a coupling length of about 27 and 350 urn for the TM- and TE-polarization mode, respectively, an extinction ratio of 17 dB, and an insertion loss of less than 1 dB for a gap width of 30 run and InP-cladding layer thickness of 135 nm at 1.55 um wavelength.