The Design And Study On Characteristics Of Three-wavelength THz Filter Based On Triple Lattice Photonic Crystals

As the last frequency window with no comprehensive understanding and utilizing in theelectromagnetic spectrum, THz wave has a large bandwidth which can meet the need of THzcommunication in the future and it has great developing potential in the field of wirelesscommunication. As one of the key devices in the THz communication, researching new THz filter isof great significance. Photonic crystal has many important characteristics, such as photonic bandgap and photon localization, and applying photonic crystal technology to the THz filter has manyobvious advantages.By the combination of photonic crystal technology and THz technology, a novel type ofthree-wavelength THz filter based on triple lattice photonic crystal is proposed in this paper. A tripletriangular lattice photonic crystal which is composed of three triangular lattice photonic crystalswhich consist of circular dielectric cylinders, square dielectric cylinders and triangle dielectriccylinders respectively is firstly proposed. Then a three-wavelength THz filter is obtained byremoving a row of dielectric cylinders, which with combination of circle, square and triangle, asline defect and filling the square dielectric cylinder which is on one side of the line defect withGaAs as point defect. Finally the characteristics of this filter are analysed through simulation.The simulation results show that the triple lattice photonic crystal which has a larger gap width,reaching0.19453, is superior to simple lattice photonic crystal. Beside, the three-wavelength THzfilter of which filtering efficiency is95.533%, insert loss is8.927dB, channel isolation is0.1432dB,response time is150ps, can select the wavelength71.48μm,73.976μm and80.506μm at the sametime and the corresponding frequency band width is0.01145THz,0.00723THz and0.00723THz.This filter has important application prospect in the THz communication system in the future.