Polarization characteristics of chiral photonic crystal fibers with an elliptical hollow core

The theoretical study of dielectric-chiral photonic crystal fiber (PCF) with an elliptical hollow core is presented. The band structure of chiral photonic crystal (PhC) is calculated by using a modified plane-wave expansion (PWE) method. By examining the out-of-plane photonic bandgaps (PBGs) of chiral PhC, a kind of chiral PCF with a hollow core is designed and their eigenstates are calculated. The distributions of mode field and polarization state are demonstrated, and how the structural asymmetry of the core together with the chirality in the background affects the modal polarization is discussed. The dependences of birefringence on chirality for different ellipticities of core are investigated.