Methods of fabricating photosensitive substrates suitable for optical coupler

Abstract

The present invention provides a method to fabricate an optical coupler comprising the steps of: preparing a photosensitive glass substrate comprising at least silica, lithium oxide, aluminum oxide, and cerium oxide; masking a halftone design with variation in optical density to delineate an optical element in the glass; exposing the photosensitive glass substrate to an activating energy source; exposing the photosensitive glass substrate to a heating phase of at least ten minutes above its glass transition temperature; cooling the photosensitive glass substrate to transform at least part of the exposed glass to a crystalline material to form a glass-crystalline substrate; and etching the glass-crystalline substrate with an etchant solution to form the one or more optical elements.

Dependencies are inferred from the claim text.