Theoretical study on photonic crystal tunable filter with multiple channels

In order to implement the multi-channel filtering of the photonic crystal, the numerical calculation and theoretical analysis for the one-dimensional photonic crystal were performed. The result indicates that the wavelength of the multi-channel transmission peak presents linear variation with the optical thickness of the air layer, the air layers with different thickness can capture the different numbers of the transmission peaks, and the FWHM of multi-channel transmission peak is decreased with the increase of the photonic crystal refractive index. Based on the results, the one-dimensional photonic crystal three-channel tunable filter, whose filtering channel has a tunable wavelength range of 60nm, a tunable range of FWHM is 1nm～5nm, and a transmission peak is 0.98, was designed.