Research On Etching Process Optimization Of Titanium Dioxiode Waveguide

Titanium dioxide is a very promising material.It has unique photocatalysis characteristics and excellent optical properties,such as high refractive index,wide transparent window from visible light to infrared,low two-photon absorption and high nonlinearity.In addition,by means of coating and etching technology,titanium dioxide can achieve on-chip integration and realize high-performance non-linear applications,such as supercontinuum,optical frequency comb;or realize titanium dioxide super surface,such as structural color,super lens,enhanced photocatalysis,etc.;at the same time,it can also be applied in whispering-gallery optical microcavity,using high-Q titanium dioxide optical microcavity,such as enhance the interaction with materials,optical sensing and other applications.Titanium dioxide on-chip integrated devices can be prepared from the bottom up by magnetron sputtering,atomic layer deposition and other methods,or the top-down semiconductor process can be used.Considering the compatibility with CMOS process,a top-down semiconductor process is adopted in this paper.Firstly,Ti O2 thin films are prepared by vacuum electron beam evaporation.The detailed preparation process is given in this paper.The crystal phase and optical properties of the films were characterized.Then we discuss the optimization of the stripping process and the evaporation process of the metal mask,and give the optimization results.After a brief introduction of the principle of ICP etching,the influences of various process parameters of ICP etching,such as gas pressure,ICP source power,RF source power and etching time,on the etching depth,side wall angle,perpendicularity and other factors are analyzed,and the detailed optimization process and results are given.Using the optimized etching process,Ti O2 waveguide and microring are designed and fabricated in this paper.Firstly,the mode characteristics of whispering-gallery optical microcavity are analyzed,and the important parameters of whispering-gallery microcavity are discussed.Then,the experimental device of Ti O2 waveguide microring experiment is introduced.The Q value of microring is measured by using Ti O2 grating directional coupler or lens fiber for direct coupling at the end.The transmission spectrum data of Ti O2 whisper gallery optical microcavity prepared by us are measured experimentally.By Lorentz fitting,the quality factor of Ti O2 microring can reach more than 30 000.In order to control the transmission mode in waveguide,we introduce the gradient meta-surface.The super surface consists of a series of two-dimensional micro nano structures.When the light incident on the micro nano structure,due to the scattering effect of the micro nano structure,it can be concluded that the amplitude and phase changes of the light compared with the incident light.Through the special design of the size,shape and arrangement of the micro nano structure,the propagation of light can be regulated.In this paper,we design a silicon antenna micro nano array on the titania waveguide,and use the collective scattering effect of the micro nano antenna array to provide an equivalent wave vector keff for the transmission mode in the waveguide,so as to realize the regulation of the mode in the waveguide.In this paper,a design of antenna array is proposed,which transforms te fundamental mode transmitted by waveguide with width of 1.2 ?m and thickness of 0.8 ?m into TM fundamental mode,and the simulation results are given.