Study On Dirac Half Metal Subwavelength Grating Waveguide Filter

With the development of information technology,the amount of information exchange has increased.Traditional electrical chips can no longer meet the increasing demand for information transmission of people.At this time,integrated optical chips were born,and optical communication came to the stage.In the field of optical communication,the optical filter is essential for a communication system.Optical signals with specific wavelengths are allowed to pass through optical filters.It can not only filter out the noise doped in the signal,so as to restore the original signal,but also can be used for wavelength division multiplexing and the selection of specific wavelength signals.It plays a key role in the level of signal transmission quality.Many excellent photonic integrated devices can be designed based on the subwavelength grating waveguide,which can flexibly adjust its period and duty ratio to change the effective refractive index of the subwavelength grating waveguide.The three-dimensional Dirac semimetal Cd₃As₂ is a new material with high electron mobility,good stability in air,adjustable refractive index.The subwavelength grating filter based on Dirac semimetal which combines the performance advantages of the new material Cd₃As₂ with the structural advantages of the sub-wavelength grating,has a very broad research prospect in the field of integrated photonics.We mainly study the filter based on subwavelength grating waveguide using new optical material three-dimensional Dirac semimetal Cd₃As₂.Designed and manufactured several filters are in line with modern processing and manufacturing technology,with small device size and good filtering performance.Theoretically analyze and simulate of these devices are analyzed by the COMSOL Multiphysics software based on the finite element method.The main research work of this study are as follows:1.We designed an adjustable frequency selective filter based on Dirac semimetal subwavelength grating waveguide.The filter is composed of a silicon dioxide substrate,a rectangular silicon block,two subwavelength grating structure Cd₃As₂ bus waveguides and a subwavelength grating structure Cd₃As₂ microring resonator.The output wavelength of the microring resonator is effectively controlled by adjusting the voltage of the arc segment where loading the voltage.The simulation results show that when the chemical potential energy of the arc segment of voltage changes from 0eV to0.25eV,the output resonance wavelength shifts from 1575.4nm to 1576.3nm,and the light wave transmittance is above 91%.2.We designed a TE₀ mode blocking filter based on Dirac semimetal subwavelength grating waveguide.The filter consists of a silicon dioxide substrate,a Cd₃As₂ strip,and a Cd₃As₂ strip with subwavelength grating structure.The simulation results show that in the 1567nm¹582nm band,when the input is TE₀ mode light wave,the filter extinction ratio?24.7dB;when the input is TE₁ mode light wave,the filter insertion loss is?0.12dB.