Design of compact polarization rotator using simple silicon nanowires

In this paper, an ultracompact design of a polarization rotator (PR) based on a silicon-on-insulator (SOI) platform is presented. The design contains two simple silicon nanowires but with unequal width, which will be easier to fabricate. It is shown here that a low-loss, wide-bandwidth, and 52.8-μm-long compact PR with polarization cross talk of -20  dB can be achieved. A full-vectorial finite element method and the least-squares boundary residual method are used to study the effects of the fabrication tolerances. This design shows reasonably stable performances.