Optical waveguides formed by thermal migration of ions in glass

Abstract

Optical waveguides were formed by increasing the index of refraction of a glass substrate by exchanging constituent glass ions in a small region near the surface. The glass refractive index is related to the density of the ions and to their polarizabilities. Tl <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> , K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> , and Ag <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ions were thermally diffused into the glass and resulted in a region of higher index. Index changes as high as .15 and waveguide thickness up to several microns were measured.