Design And Research On Two-Dimensional Subwavelength Gratings In Integrated Photonic Devices

As people's demand for communication capacity increases,the requirements for optical communication systems for device performance continue to increase.Optoelectronic devices are moving toward easy integration,high performance,low power consumption,and small size.Planar components based on diffractive optics(gratings,Fresnel lenses)and thin film optics(dielectric filters,Bragg reflectors)have existed for decades.However,in recent years,with the continuous improvement of surface element theory and the continuous improvement of micro-nano manufacturing technology,planar components have once again become a research hotspot.Among them,the sub-wavelength grating is a novel micro-nano structure grating.By adjusting the structure and size of the grating,the basic properties(amplitude,phase,polarization)of the light can be controlled.Based on this principle,the flexible design of the optoelectronic integrated device can be realized.In this master's thesis,the subwavelength grating is applied to the design and research of optoelectronic integrated devices.The regulation characteristics of the cylindrical subwavelength grating on the light field are mainly studied.A cylindrical subwavelength grating with polarization insensitivity,high reflectivity and convergence characteristics is designed.The performance of the cylindrical subwavelength grating with square and regular hexagonal arrangement is analyzed.A non-periodic sub-wavelength grating mirror with angular deflection function was designed,processed,and tested.The specific research contents and innovative achievements are as follows:1.A cylindrical sub-wavelength grating with polarization insensitivity,high reflectivity and focusing characteristics is proposed.The cylindrical sub-wavelength grating adopts a regular hexagon array arrangement,and the incident light with a wavelength of 1550 nm can achieve a focal convergence of 6 p,m,the full width at half maximum of the focal spot is 1.14 ?m,and the focal depth is 1.73 ?m.The simulation results show that the reflectivity of the entire mirror is 61.3%.From the microscopically,the cylindrical structure has rotational symmetry.Compared with the sub-wavelength grating of the two-dimensional block structure proposed earlier,the device based on the cylindrical sub-wavelength grating is more susceptible to polarization insensitivity.2.The optical field control performance of a cylindrical sub-wavelength grating with regular quadrilateral and regular hexagonal arrangement is compared and analyzed.In this paper,two kinds of planar focusing reflectors based on cylindrical sub-wavelength gratings are designed by square and regular hexagonal arrays respectively.The influence of the arrangement method on the convergence effect is analyzed and compared,and the cylindrical sub-wavelength grating is obtained with regular hexagons.The conclusion that the convergence effect of the array is better,especially the arrangement of the positive hexagonal array on the peak energy of the convergence plane is 1.64 times that of the square array.This conclusion will be instructive for the design of cylindrical sub-wavelength grating arrays.3.A non-periodic sub-wavelength grating mirror with angular deflection function was designed,processed,and tested.Since the top of the "one-mirror oblique three-mirror cavity" photodetector needs to integrate a mirror with a small angle de:flection function.In contrast,the non-periodic subwavelength grating plane mirrors that enable angular deflection are a good choice.An angle-deflecting plane mirror was designed,fabricated and tested based on a one-wavelength grating.The mirror was experimentally measured to achieve a deflection reflection of about 17°.