Patent ID: 6711918
Filing Date: 2004-03-30
Classification: C03B,H01S

Abstract:
A method for providing a class preform for use as a source for drawing an optical fiber, the method comprising the steps of:collecting a plurality of first glass rods into a substantially contiguous bundle, wherein each of said first glass rods comprise a chemical composition and a substantially uniform shape; inserting said contiguous bundle into a glass tube, wherein said glass tube has an inside diameter chosen to contain said contiguous bundle, forming thereby a preform assembly; removing and replacing one or more groups of contiguous first glass rods with an equivalent number of groups of contiguous second glass rods, wherein said one or more groups consists of a single, contiguous core bundle of second glass rods inserted about a central longitudinal axis of said preform assembly, wherein each of said second glass rods comprise a chemical composition and a substantially uniform shape, and wherein said second glass rod chemical composition comprises one or more rare-earth dopant elements, said step of removing and replacing further including inserting a stepped template against one end of each of said first glass rods, said stepped template having one or more steps or plugs, said steps or plugs acting to partially displace said one or more groups of first glass rods; and heating said preform assembly to a glass fusion temperature and causing said preform assembly to fuse to form a solid glass preform such that said chemical composition of each of said first and said second glass rods is maintained in a location proximate to, or about coincident with, the position of each of said glass rods within said contiguous bundle.