Design And Performance Analysis Of A Multi-wavelength Terahertz Modulator Based On Triple-lattice Photonic Crystals

In recent years, the demand for wider bandwidth in short-range wireless communication systems is rapidly increasing. Terahertz wave has the advantages of broad bandwidth, good directivity and large information capacity, so terahertz communication will be the inevitable direction for the future development of short-distance wireless communication. In the terahertz wavelength division multiplexing communication system, multi-wavelength modulator can modulate and transfer the modulated terahertz wave. The multi-wavelength modulator also directly determines the transmission capacity and speed, so the research on terahertz wave modulator has important academic significance and potential application value.Photonic crystal has the characteristics of photonic band gap and photonic localization, it provides a new method for the control of terahertz waves as a new type of artificial electromagnetic materials. In this paper, we combine the terahertz technology and photonic crystal technology, and we design a multi-wavelength terahertz wave modulator based on triple triangular lattice photonic crystal structure. In the triple triangular lattice photonic crystal structure, each square point defect has three defect modes, so two square point defects will have six defect modes. The point defect will be filled with nonlinear material saAG, through the change of the pump light applied on the point defect will achieve the on and off modulation of the incident terahertz wave. The structure of the modulator is optimized using Rsoft software, the performance of the incident of single wavelength, three wavelengths and six wavelengths are analyzed in detail. According to the simulation results, the insertion loss of single wavelength incident is about 0.02 dB, the extinction ratio is about 42 dB. The insertion loss of three wavelengths incident is about 0.025 dB, the extinction ratio is about 34 dB. The insertion loss of six wavelengths incident is about 0.08 dB, the extinction ratio is about 32.15 dB. The modulation rate is about 1.5GHz, and the channel isolation rate is about 48 dB. The performance of the multi-wavelength terahertz wave modulator is excellent, it has important application value in the future terahertz communication system.