Patent ID: 8515231
Filing Date: 2013-08-20
Classification: C03B,G02B,Y02P

Abstract:
1. A method of fabricating an optical fiber preform that includes a deep index trench including a shallower outer trench portion formed on a substrate tube and a deeper inner trench portion formed on said shallower outer trench portion, each of said shallower outer trench and deeper inner trench portions comprising multiple silica layers, wherein said method comprises the steps of: (1) forming each layer of said shallower outer trench portion in a single-pass deposition of a F-containing silica layer; and (2) forming each layer of said deeper inner trench portion in a double-pass deposition in which, in a first pass, a layer of silica soot is deposited and then, in a second pass, the soot is sintered in the presence of SiP