Preparation And Optical Properties Optimization Of Ti/LiNbO₃ Waveguide Optical Coupling Plate Based On Titanium Diffusion

Optocouplers are one of the most important optical passive components in optical fiber communication.With the increasing demand for optocouplers and the trend of integration in the development of optical fiber communications,the integration is becoming more and more obvious.Integrated,low loss and easy access to achieve multi-channel and miniaturized waveguide-type optical coupler has become the main direction of research.Titanium/lithium niobate optical waveguide is one of the research hot spots.The subject of lithium niobate and titanium metal as raw material,the use of vacuum evaporation and metal diffusion technology to produce titanium/lithium niobate waveguide type optical coupling sheet,through the study of evaporation current,substrate temperature and evaporation time Ti/LiNbO₃ composite thin film microstructure and determine the best vacuum evaporation process parameters,based on the best process parameters,the use of metal diffusion method for the preparation of titanium/lithium niobate waveguide optical coupling sheet,The effects of diffusion temperature,diffusion time and the initial thickness of titanium film on the microstructure and macroscopic optical properties of titanium/lithium niobate optical coupling films were investigated,and the optimum diffusion process parameters of titanium/lithium niobate optical coupling films were determined.Lithium niobate is used as the substrate material,metal titanium is the evaporation source,and titanium/lithium niobate composite film is prepared by vacuum evaporation method.The best vacuum deposition is obtained by XRD,SEM,EDS,AFM and XPS.Process parameters.The prepared titanium/lithium niobate composite film has a small amount of titanium oxide;the fitting thickness and time are:2.708 nm/1 min.Preparation of Titanium/Lithium Niobate Optical Waveguides by In-metal Diffusion Method Based on the Preparation of Titanium/Lithium Niobate Composite Films,XRD,SEM,EDS,AFM,XPS,Raman Spectroscopy,Prism Coupling,Appearance,etc.Obtained titanium titanium diffusion method to prepare titanium/lithium niobate waveguide optical coupling sheet best process parameters.Waveguide Loss Measurement Options 2010-WGL1 was used to measure the transmission loss of a titanium/tantalate waveguide optical coupler.The results show that the cross-sectional elemental composition of the prepared titanium/lithium-column waveguide optical coupling element is mainly composed of Ti,Nb and O.The surface of the waveguide reaches the interior of lithium niobate.The content of titanium increases first and then decreases,and the increase and decrease are gradient distribution.And the titanium ions diffused into the lithium niobate crystals inside the substrate are in the Ti4+valence state.Before and after the titanium diffusion,the lithium niobate is still a single crystal lithium niobate phase?ilmenite structure?.At 1540 nm wavelength,the number of guided modes of titanium/lithium oxide light-coupled film is 1.Under the same conditions,the effective refractive index increases with the increase of diffusion time,and increases with the increase of initial titanium film thickness.The trend is that the maximum effective refractive index is 2.2144.At the wavelengths of 532 nm and 448.2 nm,there are three and four mode refractive indices for the titanium/lithium-on-lithium light-coupled optical fiber respectively.The indirect WKB approximation method is used to obtain the radial one-dimensional steady state of the coupled chip.The refractive index gradient distribution curve,the refractive index decreases monotonically from the surface of the coupling sheet to a Gaussian distribution.At the wavelength of 532 nm,the maximum refractive index of the optimal optical coupling surface is 2.33238,and the surface refractive index variation is 0.00843.The comparison results of the measured values of the surface refractive index changes of different samples are in agreement with the theoretically calculated values.Except for the incident light wavelength,the diffusion time and the initial thickness of the titanium film have an influence on the variation of the surface shot rate of the coupling sheet.