Optimal design of mid-gap with 1.55μm in two dimessional photonic crystal

The variations of band gap of two-dimensional rectangular lattice photonic crystal with the structural parameters are investigated by using the plane-wave expansion method.numerical results show that when the normalized radius of dielectric rods increases,the band gap frequency decreases and the width of band gap firstly increases and then declines.Moreover,the width of band gap increases and the mid-gap frequency declines as dielectric constant ratio increases.In particular,when the lattice constant a,normalized radius r/a and dielectric constant ratio are 0.594μm,0.16 and 13,respectively,the corresponding mid-gap wavelength is 1.55μm and the normalized band gap is 0.15.