Wideband polarization splitter and rotator with large fabrication tolerance and simple fabrication process

We propose and demonstrate a polarization splitter and rotator (PSR) built on a silicon-on-insulator platform. The PSR is constructed with a tapered waveguide followed by a 2×2 multimode interferometer and can be simply fabricated in a single lithography and etching step. A low insertion loss (<2.5  dB with minimum insertion loss of 0.6 dB) and a low polarization crosstalk (<−12  dB) over a wide operation bandwidth (∼100  nm) with a large fabrication tolerance (>50  nm) are experimentally demonstrated.