Method and apparatus for rapidly cooling optical fiber

Claim 2

An optical fiber cooler comprising: (a) a central enclosure having an axial length, an inlet end, and an outlet end, said enclosure having means for passing cryogenic gas substantially symmetrically through the wall and a flat black internal surface, along its axial length, and further having a restriction plate across each of said inlet and said outlet end, each restriction plate having an orifice therethrough of a size sufficient to enable the passage of optical fiber; (b) an insulated outer enclosure spaced from the enclosure to form a gas plenum, axially along the central enclosure from about the outlet end to a point short of the inlet end; and (c) a cryogenic gas supply conduit passing through the insulated outer enclosure, in flow communication with the gas plenum proximate said outlet end, and connected to a source of cryogenic fluid.

Claim 3

The cooler of claim 1 wherein the axial length of the central enclosure is in the range of from about 3 to 10 feet.

Claim 4

The cooler of claim 1 wherein the central enclosure is cylindrical.

Claim 5

The cooler of claim 1 wherein the central enclosure is made from heat conductive material from the group comprising copper, brass, aluminum and stainless steel.

Claim 6

The cooler of claim 1 wherein said cryogenic gas passing means comprises a plurality of perforations.

Claim 7

The cooler of claim 5 wherein said perforations comprise holes.

Claim 8

The cooler of claim 5 wherein said perforations comprise slots.

Claim 9

The cooler of claim 1 wherein said cryogenic gas passing means comprise intersticial spaces in porous sintered metal.

Claim 10

A process for rapidly cooling optical fiber from a temperature of about 1000° C. or more to a temperature below about 90° C. comprising: (a) drawing optical fiber having a temperature of about 1000° C. or more into an enclosure having means for passing cryogenic gas substantially symmetrically through its wall and a flat black internal surface, along its axial length; (b) passing the optical fiber through the axial length of the enclosure; (c) passing cryogenic gas to a gas plenum adjacent the wall and through said means substantially symmetrically through said wall along the axial length of, and into, the enclosure to cool the enclosure; (d) contacting the optical fiber with gas within the enclosure as the optical fiber passes along substantially the entire axial length of the enclosure; and (e) withdrawing the optical fiber from the enclosure at a temperature of less than about 90° C.

Claim 11

A process for rapidly cooling optical fiber from a temperature of about 1000° C. or more to a temperature below about 90° C. comprising: (a) drawing optical fiber having a temperature of about 1000° C. or more into an enclosure having means for passing cryogenic gas substantially symmetrically through its wall and a flat black internal surface, along its axial length; (b) passing the optical fiber through the axial length of the enclosure; (c) passing cryogenic gas to a gas plenum adjacent the wall and through said means substantially symmetrically through said wall along the axial length of, and into, the enclosure to cool the enclosure; (d) contacting the optical fiber with gas within the enclosure as the optical fiber passes along substantially the entire axial length of the enclosure; and (e) withdrawing the optical fiber from the enclosure at a temperature of less than about 90° C.

Claim 12

The process of claim 9 wherein the optical fiber is drawn through the axial length of the enclosure in a time within the range of from about 0.1 to 2.0 seconds.

Claim 13

The process of claim 9 wherein said cryogenic gas is nitrogen.

Claim 14

The process of claim 9 further comprising contacting the outside surface of the enclosure with cryogenic gas.

Claim 15

The process of claim 9 wherein the optical fiber is drawn from a quartz rod prior to being passed into the enclosure.

Claim 16

The process of claim 9 further comprising passing the gas through the enclosure countercurrent to the direction that the optical fiber is drawn through the enclosure.

Claim 17

The process of claim 9 further comprising passing the gas out of the enclosure at a location proximate the point where the optical fiber is drawn into the enclosure.

Claim 18

The process of claim 9 further comprising coating the optical fiber after it is withdrawn from the enclosure with a protective coating.

Claim 19

The process of claim 16 wherein said protective coating is a curable polymeric coating.

Claim 20

The process of claim 17 wherein said curable polymeric coating is cured by ultraviolet radiation.