Patent ID: 8401355

Claim:
A method of making a hydrogen-resistant optical fiber using modified chemical vapor deposition, the method comprising the steps of: a) providing a glass preform tube of a predetermined thickness and having a predetermined radial opening; b) depositing a plurality of cladding layers along the inner surface of the glass preform tube, the composition of gases used in the deposition include an index-lowering material; c) depositing a relatively few layers of germanium-doped silica over the index-lowered cladding layers; d) depositing a relatively thick pure silica single layer over the germanium-doped silica; and e) collapsing the tube to form a solid core preform, the solid core comprising an inner core region of the pure silica deposited in step d) surrounded by an interface core region of the germanium-doped silica deposited in step c), with a ratio of the relatively thick pure silica single layer to the relatively few layers of germanium-doped silica defined such that the inner core region comprises at least 65% of the solid core.