US 11,827,555 B2Granted

Optical fiber forming apparatus

AssigneeCorning Incorporated

InventorsErling Richard Anderson, Tammy Michelle Hoffmann, Nikolaos Pantelis Kladias, Robert Clark Moore, Christopher Scott Thomas

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Abstract

An optical fiber forming apparatus comprises: a draw furnace comprising: (i) a muffle with an inner surface, (ii) an axial opening below the muffle, the inner surface of the muffle defining a passageway extending through the axial opening, and (iii) an upper inlet into the passageway; and a tube that extends into the passageway of the draw furnace above the axial opening, the tube having (i) an outer surface and the inner surface of the muffle surrounds the outer surface of the tube with a space separating the outer surface of the tube from the inner surface of the muffle, (ii) an inner surface that defines a second passageway extending through the tube, (iii) an inlet into the second passageway of the tube, (iii) an outlet out of the second passageway of the tube.

Claims22

Dependent claims

An optical fiber forming apparatus comprising:

a draw furnace comprising:
(i) a muffle with an inner surface, (ii) an axial opening below the muffle, the inner surface of the muffle defining a passageway extending through the axial opening, and (iii) an upper inlet into the passageway;
and
a tube that extends into the passageway of the draw furnace above the axial opening, the tube having (i) an outer surface and the inner surface of the muffle surrounds the outer surface of the tube with a space separating the outer surface of the tube from the inner surface of the muffle, (ii) an inner surface that defines a second passageway extending through the tube, (iii) an inlet into the second passageway of the tube, (iv) an outlet out of the second passageway of the tube,
wherein, the muffle further comprises a narrowing where the passageway narrows towards the axial opening,
wherein, the tube extends upward above the narrowing, and
wherein, the axial opening of the draw furnace and the tube are positioned to be coaxial around an optical fiber being drawn from an optical fiber preform disposed within the passageway of the draw furnace.

4 more elements

A draw furnace for an optical fiber forming apparatus comprising:

a muffle with an inner surface and an axial opening below the muffle, the inner surface of the muffle defining a passageway centered about an axis and extending through the axial opening, the inner surface including:
a first straight portion with a radius from the axis that remains at least approximately constant along a length parallel to the axis;
a tapered portion disposed between the first straight portion and the axial opening, the tapered portion including a radius from the axis that decreases away from the first straight portion narrowing the passageway, and a vertical length parallel to the axis that is at least two times longer than the largest radius of the tapered portion;
and
a second straight portion disposed between the tapered portion and the axial opening with a radius from the axis that remains at least approximately constant along a length at least 75 cm, the radius of the second straight portion being 0.635 cm to 1.27 cm.

2 more elements

A draw furnace for an optical fiber forming apparatus comprising:

a muffle with an inner surface and an axial opening below the muffle, the inner surface of the muffle defining a passageway centered about an axis and extending through the axial opening, the inner surface including:
a first straight portion with a radius from the axis that remains at least approximately constant along a length parallel to the axis;
a narrowing portion disposed between the first straight portion and the axial opening, the narrowing portion including a radius from the axis that decreases away from the first straight portion narrowing the passageway;
and
a second straight portion disposed between the narrowing portion and the axial opening with a radius from the axis that remains at least approximately constant along a length parallel to the axis;
a first heating element that heats the passageway throughout a first range that encompasses a portion of the passageway defined by the first straight portion;
a second heating element that heats the passageway throughout a second range that encompasses a portion of the passageway defined by the first straight portion above the first range;
and
a third heating element that heats the passageway to a temperature of 100° C. to 200° C. throughout a third range that encompasses a portion of the passageway defined by the second straight portion.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/319,811Filed 13 May 2021 · us provisional application
Priority: 15 May 2020
Published: US 2021/0355018 A118 Nov 2021
Granted: 28 Nov 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

C03B 37/029
From reheated softened tubes, rods, fibres or filaments , e.g. drawing fibres from preforms: furnaces therefor
C03B 2205/62
Optical fibre draw furnaces: heating means for drawing
C03B 2205/63
Heating means for drawing: ohmic resistance heaters, e.g. carbon or graphite resistance heaters
C03B 2205/83
Means for sealing the fibre exit or lower end of the furnace: using gas