Fabrication And Performance Characterization Of Sc:Ti Diffusion-Doped LiNbO₃ Crystal

The photorefractive effect hinders the development of novel efficient active and passive integrated optics devices.The study found more than 2mol% scandium-doped can effectively supresses the photorefractive effect of LiNbO3.This article works on the doping characteristic of Sc3+,and fabrication process of titanium diffusion lithium niobate(LN) optical waveguide doped with scandium.The main works,1. Fabrication of lithium niobate doped with scandium(Sc:LN), and study on diffusion characteristic of Sc3+ at different tempreture, the change of refractive index and constituent of lithium niobate after doped with Sc3+.2. Further research on the diffusion properties of sc when Sc-Ti ion codiffusion3. Fabrication of titanium diffusion lithium niobate planer optical waveguide doped with scandium(Sc:Ti:LN),study on the relationship between the distribution of refractive index change,Δn(z),with distribution of titanium,CTi(z).4. Try to find the Sc:Ti:LN strip waveguide fabrication process,and furtherly to characterization waveguides.The results of this paper,1. We found Sc3+hardly affects the refractive index and constituent of LN;The distribution of scandium ion follows the Gaussian distribution and its diffusion coefficients at different temperatures satisfy Arrhenius equation.We also got the diffusion constant, and the excitation energy parameters of Sc3+.2. By measuring the refractive index of the planar waveguide, and using IWKB algorithms with scattering theory, we obtain Δn(z,λ),which is also Gaussian.Furtherly,we got the relationship of Δn(z) and CTi(z),which proved that Sc3+ affects weakly on the relationship.3. We found that Titanium ions helps scandium ion diffuse in lithium niobate crystal,at last we got the relationship between the diffusion coefficient of scandium with the titanium film thickness.The reason:the diffusion rate of Titanium ion is greater than scandium ions,so it comes in LN firstly.When the Titanium ion in,it bring a lot of flaws,which can make scandium ion diffuse quicker.4. The waveguide well supports both transverse electric(TE) and magnetic(TM)modes, is single-mode at 1.5-μm wavelength, and has a loss of 1.4 dB/cm for the TE mode and 1.8 dB/cm for the TM mode. It is proved that the fabrication process of this strip waveguide can guarantee to meet that scandium ion concentrations at 1/e distribution point is greater than 2.0mol%.This paper provides a number of reliable data and it has significance for the fabrication and optimization of active and passive integrated optics devices...