Large Absolute Band Gap Achieved by Two Dimensionally Sinusoidal Dielectric Waveguide Arrays

Complex lattice structure which can reduce the structure symmetry is most used to create or enlarge absolute band gaps. Another effective model to obtain absolute band gaps is proposed. The symmetry reduction approach in the presented model is to reduce the symmetry of the refractive index by sinusoidal modulation in square lattice. The band structure of two dimensionally sinusoidal dielectric waveguide array (SDWA) is calculated by the plane wave expansion method. We also investigate the influence of refractive index modulation on the formation of absolute band gaps. The results indicate that the SDWA model is beneficial to create and increase absolute band gaps.