Patent ID: 8794038

Claim:
A method for manufacturing a multimode optical fibre having a refractive index profile, comprising: depositing doped or undoped glass layers on the interior of a substrate tube using a reactive gas mixture; contracting the substrate tube to yield an optical preform having a refractive index profile; heating one end of the optical preform; and drawing from the heated end of the preform a multimode optical fibre comprising a gradient index light-guiding core surrounded by one or more cladding layers, wherein the gradient index light-guiding core comprises at least one refractive index-changing dopant with a concentration increasing in a radial direction from about 0 weight percent at a fibre axis (r=0) to at least about 6.5 weight percent, wherein the at least one refractive index-changing dopant in the gradient index light-guiding core includes fluorine; and wherein the multimode optical fiber has a transmission capacity of at least 1 Gbit/sec over a fibre length of at least 1300 m, and a wavelength bandwidth of at least 250 nm in a wavelength range including 1400 nm.