Ultracompact Polarization-Insensitive Power Splitter Using Subwavelength Gratings

An ultracompact polarization-insensitive power splitter using silicon-based subwavelength grating (SWG) is proposed and analyzed, where one input tapered waveguide and two adjacent inverse-tapered waveguides are embedded in the center of the SWG-wire structure. With the optimized device dimensions, the input light can be coupled from the input tapered waveguide into the adjacent inverse-tapered waveguides with the help of the SWG, and then output from the two symmetric bending channels with a polarization-insensitive transmission. Results show that a compact device of 2.5 μm in total length is achieved with an insertion loss of 0.04 dB (0.05 dB), a reflection loss of -30.24 dB (-38.23 dB) for TE (TM) mode at 1.55 μm, and the operation bandwidth of low loss can cover the O, E, S, C, L, and part of U bands. In addition, fabrication tolerances and mode-field evolution are also presented.