Band gap of 3-element 1-D defective mode photonic crystal

The band gap structure of 3-element 1-D photonics crystal with defective mode was studied by transfer matrix method，and the influence of the variation of the defect thickness on band gap structure was analyzed through numerical simulation. The simulation indicates that， for 3-element 1-D photonic crystal with symmetrically distributed defects，the defect thickness has little influence on the width of band gap；in the broader band gap，there is a sharp transmission peak, which will take red shift with increase of the defect thickness. Within a given range，the nonlinear relationship between wave length of the transmission peaks and defect thickness was presented，on which，FWHM of the transmission peak in band gap was calculated， furthermore， the relation graph between wave length FWHM