Suspended polarization beam splitter on silicon-on-insulator.

Polarization handling in suspended silicon photonics has the potential to enable new applications in fields such as optomechanics, photonic microelectromechanical systems, and mid-infrared photonics. In this work, we experimentally demonstrate a suspended polarization beam splitter on a silicon-on-insulator waveguide platform, based on an asymmetric directional coupler. Our device presents polarization extinction ratios above 10 and 15 dB, and insertion losses below 5 and 1 dB, for TM and TE polarized input, respectively, across a 40 nm wavelength range at 1550 nm, with a device length below 8 µm. These results make our suspended polarization beam splitter a promising building block for future systems based on polarization diversity suspended photonics.