Design and characteristics of a near-elliptic inner cladding High birefringent polarization-stable photonic crystal fiber

A new near-elliptic inner cladding (NEIC) structure of polarization-stable highly birefringent photonic crystal fiber (HB-PCF) is proposed and analyzed numerically by using the full-vector finite element method (FEM) under the condition of anisotropic perfectly matched layers. The result confirmed that the birefringence degradation of the proposed NEIC-PCF is less than 1.2×10 -5 when the air hole diameter of the inner cladding along the short axis varies from 1.30μm to 1.18μm (varied by ～10%)，while the average birefringence is of the order of 10 -3 at 1.55μm and the mode field diameters along long axis and short axis of the elliptic are 9.2μm and 2.4μm，respectively，which shows that the proposed PCF have excellent polarization stability.