The Basic Design Research Of Silicon-Based Micro/nano Multi-subpart Resonant Gratings

In recent years,with the rapid development of micro/nano optics and micro machining technology,based on the combined merits of simple structure,easy integration and simple fabrication,micro/nano gratings have attracted increasing interest because of reducing the size of optoelectronic devices,the power consumption,improving the integration and performance of optoelectronic devices.Among them,based on the diffraction characteristics of micro/nano grating leaky mode resonance,micro/nano grating has attracted the world attention of research workers for its unique and great scientific significance and application value.Compared with uniform gratings,the multi-subparts gratings have the advantages of increasing design freedom,controlling over the Fourier series component distribution in the grating region and preventing the rapid decay of the leaky modes.They can offer the combined merits of high reflectivity and good angular over a broadband spectrum.Supported by the “National Natural Science Foundation of China” and “International cooperation and exchange project of the National Natural Science Foundation of China”,the thesis mainly systematically focuses on the design and optimizations of the multi-subparts profile gratings,and several efficient optical transmission and control devices are designed,which can be widely used in laser,optical detection,solar cell and optical communication system.A number of achievements are obtained as following:(1)In the thesis,based on the coupled-wave analysis rigorous(RCWA),a numerically stable and systematic implementation of the RCWA for the general silicon-on-insulator(SOI)multilayered two-dimensional grating structures is presented,which can provide a theoretical reference for revealing and exploring the propagation characteristics of light wave in these devices.(2)Based on the photonic band theory,by using the method of plane wave expansion(PWE),the dispersion characteristics of multi-subpart profile resonant gratings is studied,and then a multi-subpart profile resonant slow light grating with broadband width is designed.Subsequently,a numerical analysis is made on the characteristics of the grating parameters and the slow light using the PWE method.Finally,a scheme to realize broadband slow light is presented,which can be realized in series with multi-subpart profile gratings.(3)A polarization selective beam splitter(PSBS)constructed by only a single layer subwavelength multi-subpart profile grating is also proposed and demonstrated.It is shown that for transverse electric(TE)polarized wave,the device demonstrates very high reflectivity(>97%)from 1.46 to1.58μm;and for transverse magnetic(TM)polarized wave,at the wavelength of 1.55μm,it exhibits about 50/50 beam ratio under normal incidence.To evaluate the response of the PSBS under variation in structure parameters,we also investigated the fabrication tolerances of the device.(4)In this thesis,a non-polarization reflector constructed by a multilayered one-dimensional grating structure with multi-subpart profile is proposed and fabricated.Rigorous coupled-wave analysis(RCWA)for multilayered grating structure is adopted to theoretically investigate the properties of the structure.And experimental verification of theoretical investigation is accomplished.It is shown that in both TE and TM polarized waves the device experimentally demonstrates a wideband reflection spectrum from 1.65 to 1.72μm,very high reflectivity(R>97%),low insertion loss(IL<0.25dB)and polarization-dependent loss(PDL<0.18dB)and a good angular insensitivity of about 24.6°.And a reasonably good tolerance of fabrication error is also presented by numerical analysis of device performance degeneration resulting from parameter deviations.(5)Finally,based on the effective medium theory(EMT)and FDTD,a high performance grating coupler with multi-subpart profile is presented and demonstrated.It is shown that for TE polarized wave,the coupler has the coupling efficiency of 71% at 1.55μm.Subsequently,to evaluate the response of the grating coupler under variation in structure parameters,a numerical analysis is made on the characteristics of the device.