Design And Performance Analysis Of Multi-wavelength Compound Lattice Photonic Crystal Switch For The Terahertz Range

THz communication has huge potential to be applied to future high-speed, ultra-broadband wireless communications. It has been the international hot research area. THz wave switch is one of the key devices in the THz communication system.With the rapid development of WDM in THz communication system, the study on THz multi-wavelength switch will have important significance.Photonic crystal has many important characteristics, such as photonic band gap and photonic localization, the combination of THz technology and photonic crystal technology has many obvious advantages in designing THz switch.A new kind of THz multi-wavelength optical based on compound square lattice photonic crystal is proposed in this paper. The switch is based on defect modes disappear principle. Compound lattice photonic crystal is used in optical switch where a line defect and two point defects have been introduced. The two point defects are square point defect and circular point defect respectively.Point defects and line defects are coupled by side coupling,point defects is designed by introducing optical-controlled materials GaAs.0ne point defect should have two different defect modes in compound lattice photonic crystal. The article also Changes the size of medium column surrounding the point defect to enhance the performance of point defect cavity,it can make the point defects localize photons stronger and the optical switch has better extinction ratio. The THz optical switch can be simulated by the FDTD method of RSOFT,we can also optimizate the size of the point defect by the FDTD method of RSOFT.The simulation results show that the optical switch can effectively control “on” and “off” of four THz waves,ther are 63.366μm、68.587μm、65.181μm、68.358μm,respectively.With incidence of single wavelength,the corresponding extinction ratio of a single wave is 0.07dB、0.04dB、0.04dB、0.12 dB and the corresponding insertion loss of a single wave is 49.14dB、31.15dB、30.05dB、31.02 dB.With incidence of 63.366μm、68.587μm,the extinction ratio is 0.09 dB,the insertion loss is 42.51dB;With incidence of 63.366μm、68.587μm,the extinction ratio is 0.11 dB,the insertion loss is 37.99dB;With incidence of four wavelengths, the extinction ratio is 0.13 dB,the insertion loss is 32.88dB;The swtich rate is about 4.35 GHz.It has a huge potential and will be wildly used in the short distance high speed optical communication in the future.