Design of miniaturized silicon wire and slot waveguide polarization splitterbased on a resonant tunneling.

We propose an ultra-small polarization splitter based on a resonant tunneling phenomenon. This polarization splitter consists of two identical horizontally oblong silicon wire waveguides separated by a vertical slot waveguide. The structural parameters of the central resonant slot waveguide are designed to couple only the TM-like mode between the left and right side silicon wire waveguides. Results from numerical simulation with the full-vectorial beam propagation method show that a 16-mum-long polarization splitter with extinction ratio better than -20 dB on the entire C-band is achieved.