Dispersion Engineering And Design Of Grating Coupler Based On Alumium Nitride Waveguide

Aluminum nitride is one type of semiconductor which possesses the widest band gap so far.Due to this property,Al N are able to work on the wavelength from ultraviolet to infrared.For utilizing the superior optical performances,it is proper to apply Al N in waveguide device.owing to the wide gap of Al N,Al N based waveguide has lower nonlinear loss at the aspect of two-photon absorption and free-carrier absorption.In this manuscript,the waveguide properties of Al N semiconductor were analyzed based on the group velocity dispersion.Dispersion is the main factor to cause wide waveform in waveguide.In the design of optical devices,we want to minimize the impact of dispersion on optical signals.In this paper,four kinds of basic structures of slot aluminum nitride waveguide are designed.Through the analysis of bandwidth and dispersion value,the influence of each structural parameter on the group velocity dispersion curve is analyzed in detail so that the dispersion curve can be flat over a wide range of wavelengths.Ultra-band flatten dispersion in double-slot Al N waveguide is obtained.Chromatic dispersion optimization can improve the nonlinear characteristics of aluminum nitride waveguide,further study on non-linear aspects can be developed.Due to the high second-order nonlinearities of aluminum nitride,the wavelength conversion process based on the non-linear effect in the aluminum nitride slot waveguide is further studied.Conversion between fundamental TE mode with fundamental TM mode is realized in the single-slot waveguide.By optimizing the waveguide structure,the mode conversion from mid-infrared to near-infrared is analyzed.The conversion from fundamental mode to high-order mode is realized at the double frequency of the pump wave,which laid the foundation for the experimental verification of the second harmonic in aluminum nitride waveguide.Based on the third-order nonlinearity of aluminum nitride,the wavelength conversion in dual-slot aluminum nitride waveguide is analyzed.The pump wavelength is selected near the zero-dispersion wavelength to analyze the phase matching conditions in the four-wave mixing process.Wavelength conversion based on the degenerate four-wave mixing effect is realized,and analyze the influence of the transmission length of the waveguide on the conversion bandwidth and the conversion efficiency to achieve the conversion result in the broadband range.This is conducive to the application of aluminum nitride waveguide in the mid-infrared band.Aiming at the research of aluminum nitride optical devices,grating coupler based on aluminum nitride material is designed.Respectively design one-dimensional and two-dimensional grating coupler,the grating parameters are optimized,and thediffraction characteristics of the grating are analyzed.The external light source can be coupled into the optical waveguide.The unique advantages of aluminum nitride semiconductor materials can be exerted to promote the performance optimization of optical devices,and increase the diversity of optical devices.