The Study On Characteristics Of Dual-Wavelength Terahertz Modulator Based On Optical-control Compound Triangular Lattice Photonic Crystal

As the last gap in electromagnetic spectrum, the THz region(0.1THz and10THz) has hugepotential to be applied to future high-speed, ultra-broadband wireless communications. THz wavemodulator is the key element in future THz wireless communication systems. It has receivedextensive investigations among scholars domestic and abroad. In this paper, THz technology andphotonic crystal (PC) are combined to design THz modulators. The study on the optical-controltunable photonic crystal THz modulator has great significance to promote the development of THztechnology.The modulating mechanisms of THz modulator based on the tunable PC are firstly analyzed,and then the THz modulator based on optical-control compound triangular lattice PC is presented.The compound triangular lattice PC has an advantage of a larger band gap over simple lattice andcompound square lattice of common PCs. On basis of compound triangular lattice PC, two kinds oftunable PC THz modulators based on disappearing or shifting theory of defect mode are designedby introducing optical-controlled materials of polyaniline and GaAs. The condition of theappearance of one and two defect modes is discussed when different nonlinear materials filled insingle point defect. Then the impact of imaginary index of GaAs on the defect mode andmodulation performance is analyzed. With the simulation software of FULLWAVE, theperformance of the proposed two devices is finally discussed, including the transmission spectrum,extinction ratio, insertion loss, modulation rate, steady-state energy distribution.Through the simulation, the width of maximum BG of the compound triangular lattice PC is0.16915, and the value is superior to simple lattice PC and compound square lattice PC. The THzmodulator based on optical-control material of polyaniline has the modulation rate of10GHz,extinction ratio of21.7dB and the insertion loss of0.31dB. The dual-wavelength THz modulatorbased on optical-control material of GaAs has the superior performance with the extinction ratios of44.03dB and50.43dB, the insertion losses of0.21dB and0.07dB, modulation rates of3.85GHz and3.57GHz. In the end, based on the the proposed devices, its applications and prospects in futurewireless THz communication systems are briefly discussed.