Compact and fabrication-tolerant polarization splitter based on horizontal triple-slot waveguide.

A compact and fabrication-tolerant polarization beam splitter (PBS) based on the horizontal triple-slot waveguides is proposed and optimized by using the rigorous H-field-based full-vectorial finite element method and the least-squares boundary residual method. It can be noted from the simulation results that a fabrication-tolerant PBS with a compact length of 33 μm can be yielded based on the horizontal triple-slot waveguides. The polarization extinction ratios are -21.8 and -20.3  dB at 1.55 μm wavelength for the quasi-TE and quasi-TM modes, respectively. The 1 dB bandwidth is 100 nm for both the polarizations. The fabrication tolerances are also thoroughly calculated for the proposed PBS.