Design of tapered polarization splitter based on EC-CHFs by full-vectorial FE-BPM using coordinate transformation

We propose and design a tapered polarization splitter (PS) using the single-polarization property of an elliptical-hole core circular-hole holey fiber (EC-CHF). It is reported that polarization splitting without any crosstalk is enabled using the PS with EC-CHF. In this paper, we show that the mode coupling is enhanced with a tapered PS structure, and the full waveguide separation at the input and output ends can be simultaneously realized. We also propose a full-vectorial finite element beam propagation method using coordinate transformation to efficiently analyze a waveguide whose structure varies along the longitudinal direction. In this approach, computational accuracy and efficiency are greatly improved.