Analysis of mode properties of photonic crystal fiber with high birefringence

The mode cutoff, confinement loss, modal radius, and numerical aperture of photonic crystal fiber (PCF) with high birefringence were analyzed by using full-vector finite difference frequency domain (FDFD) method. The numerical simulation results shown that, by choosing suitable structural parameters, the birefringence of the PCF may reach the order of 10^-3 with broad single-mode region (600 - 1800 nm). A low confinement loss less than 10^-4dB/m and high numerical aperture can be obtained in a properly designed geometrical structure of PCF, so the focusing ability is enhanced. Moreover, by fitting the distribution of the fundamental mode using Gaussian curve, the obtained modal radius agrees well with the actual one.