Fabrication And Research Of Waveguides Based On Ion Exchange

As the foundation of integrated optics, waveguide of any kind has been receiving much attention and applying in many cases. And ion exchange is an important way to fabricate waveguides as it has a much simpler process and also can yield high repeatability and bring low loss of energy. The main work of this paper is as follows.First of all, the theory about ion exchange is introduced, and also the diffusion equation of Ag+ ion in glass substrate is discussed as well as the main cause to increase of the refractive index by ion exchange. And furthermore, the one-dimensional diffusion equation is calculated. After that, the method to obtain the effective refractive index and the refractive index profile is detailed using prism coupling to get the effective refractive index and inverse WKB to get the others.Second of all, the process of ion exchange technology is discussed using silicon substrates and phosphate substrates. And through many experiments and research of this thesis, the main factor effecting yield is detailed which are Ag+ ion concentration, time used and the temperature. Moreover, the relationship between the waveguide's properties and process factor is obtained. And the Ag+ concentration mainly affects the increase of refractive index, and time and temperature affect the concentration depth.Last, the refractive index is obtained using MATLAB. And also the absorption spectrum of waveguides is obtained using a UV-VIS spectrometer. When the Ag+ concentration reaches 3% and time and temperature reach 3h and 350℃, the absorption spectrum remains the same as well as the Ag+ contend.