Study on the variation of Bragg propagation period in elliptic bar chain structure

Abstract

In this paper, the propagation of light along a long chain of two dimensional elliptic bars with infinite period is analyzed. Due to the instability of the shape of the ellipse, the propagation characteristics of light will be changed by changing the ratio of the short half axis length to the long half axis length of the ellipse. The Bragg propagation period is observed by the change of phase constant and attenuation constant with the normalized frequency. The waveguide mode, cut-off mode and leakage mode were explained by analyzing the numerical value and field distribution of the cycle results of a single layer elliptic cylinder with different ratios. The results also indicated that, as the ratio increased, the propagation period of Bragg wave became shorter and special multimodal phenomena emerged. In addition, 20 dielectric bar chain structures are used to visually show the electric field propagation.