Study highly birefringent hybrid lattice structure photonic crystal fiber

A novel hybrid lattice photonic crystal fiber (PCF) with high birefringence is proposed, which is composed of circular and rectangular air holes. Based on the finite element method, the mode field distribution and birefringence properties of the hybrid lattice PCF can be numerically analyzed by COMSOL software. The influence of the geometric parameters on the birefringence and beat-length characteristics has been investigated. The results show that the birefringence increases with wavelength and remains the order of 10^-2 within the wavelength ranging from 0.4μm to 2.0μm. In particular, the birefringence reaches 3.4849×10^-2 at the operating wavelength of 1550nm when the air hole pitch, the rectangular air hole area and the circular air hole diameter are 1μm, 1μm×0.1μm and 0.96μm respectively. The proposed fiber has broad application prospects in polarization maintaining and fiber sensor system.