Rit method of making optical fiber having depressed index core region
AssigneeCorning Incorporated
InventorGeorge F. Berkey
Life of this patent
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Abstract
Disclosed is a method of making an optical fiber preform having at least one annular region of depressed refractive index. A tube of silica doped with fluorine and/or boron is overclad with silica soot. A core rod is inserted into the overclad tube and the resultant assembly is heated while chlorine flows between the tube and the core rod to clean the adjacent surfaces. When the soot sinters, the tube collapses onto and fuses to the rod. The resultant tubular structure is formed into an optical fiber which exhibits low attenuation as a result of the low seed count at the interface between the inner core and the region that is doped with florine and/or boron.
Claims30
A method of making an optical fiber comprising:
- forming a tubular porous glass preform having an aperture therethrough;
- placing the porous glass preform in a furnace and heating the preform while injecting a fluorine-containing gas into the furnace to form a fluorine doped porous glass tube;
- heating the fluorine doped tube to sufficiently consolidate the tube into a consolidated glass fluorine doped tube;
- positioning a glass rod within the consolidated fluorine doped glass tube;
- collapsing the tube onto the rod to form a core glass preform;
- depositing a cladding material on the core glass preform;
- sintering the cladding material to form an optical fiber preform;
- and
- drawing a fiber from the optical fiber preform, the fiber having a cladding comprising a refractive index at least as high as the refractive index of pure silica, the cladding being adjacent a region of the fiber formed by the fluorine doped tube.
A method of making an optical fiber, comprising the steps of:
- forming a consolidated glass rod containing a refractive index increasing dopant,
- forming a consolidated glass tube containing a refractive index decreasing dopant,
- inserting the rod into the tube and fusing the rod and tube together to form a consolidated core,
- depositing cladding comprising silica soot on an outer surface of the consolidated core,
- sintering the silica soot to form a consolidated optical fiber preform;
- and
- drawing an optical fiber from the fiber preform, the fiber having a cladding comprising a refractive index at least as high as the refractive index of pure silica, the cladding being adjacent a region of the fiber formed by the tube having the refractive index decreasing dopant.
A method of making an optical fiber, comprising:
- forming a glass rod exhibiting a first refractive index and containing a first dopant,
- forming a silica tube including a second dopant, the tube exhibiting a second refractive index different than the first refractive index,
- consolidating the glass rod and tube thereby forming a consolidated core, and
- depositing cladding comprising silica soot on an outer surface of the consolidated core, and
- drawing the consolidated core having a cladding consisting of silica into an optical fiber, the cladding being adjacent a region of the fiber formed by the tube having the second dopant.
A method of making an optical fiber comprising:
- forming a tubular porous glass preform having an aperture therethrough;
- placing the porous glass preform in a furnace and heating the preform while injecting a fluorine-containing gas into the furnace to form a fluorine doped porous glass tube;
- heating the fluorine doped tube to sufficiently consolidate the tube into a consolidated glass fluorine doped tube;
- positioning a glass rod within the consolidated fluorine doped glass tube;
- collapsing the tube onto the rod to form a core glass preform;
- depositing a cladding material on the core glass preform;
- sintering the cladding material to form an optical fiber preform;
- and
- drawing a fiber from the optical fiber preform, the fiber having a cladding comprising a refractive index at least as high as the refractive index of undoped silica, the cladding being adjacent a region of the fiber formed by the fluorine doped tube.
Dependencies are inferred from the claim text.