Buried Concentration Profiles for Optical Waveguides by One-Step Electro-Diffusion Process: Theoretical Analysis

Abstract

IntroductionIn recent years, a two-step electric field assisted diffusion or ion-exchange technique has been extensively studied for producing buried concentration profiles in glass [1,2,3], polymer [4,5], electrooptic and semiconducting [6,7] substrate materials to fabricate buried optical waveguide devices. The technique contains two separate diffusion processes and is quite complicated, cost and time consuming. In addition, theoretical analysis of the technique is too complicated to be used for calculating and tailoring concentration profiles. Many efforts have been made to pursue a one-step process for producing buried profiles. Very recently, a novel one-step technique [8] involving electric field assisted diffusion of silver ions into glass from molten AgNO3 bath with decaying silver concentration has been developed to produce buried Ag+ concentration profiles in glass substrate. The new technique is, from the practical operation point of view, relatively simple and is a significant improvement over the conventional two-step process.