Design of a large effective mode area photonic crystal fiber with modified rings

A photonic crystal fiber (PCF) is proposed that, through novel design, achieves an enhanced effective mode area. The PCF is composed of two concentric elliptical cores. The central core is un-doped silicon whilst the second, outer core region, is doped. The outer doped region is also bordered by lightly doped half ellipse segments. The effective mode area of the structure was calculated and compared with the mode area of conventional PCF's. Our results show that the mode area and chromatic dispersion are very sensitive to the geometry, dimensions and placement of the lightly doped segments. The chromatic dispersion, bend losses and the nonlinear coefficient are also numerically simulated and presented in this paper.