Study transmission characteristics of graded photonic crystal as low pass filter

Abstract

Here, we investigate propagation characteristics of graded thickness one-dimensional photonic crystal structure made of silicon and air. The optical transmission is obtained by transfer matrix method (TMM) and studied impact of graded index and refractive index variation on the transmission spectra. The optical transmission of suggested structure drops as frequency increases and falls to zero more rapidly as graded index increases. The graded index variable can be used to tune the suggested structure’s cut off frequency, which corresponds to half of the transmission value. So, such device has useful application as tunable optical low-pass filter.