System and methods for processing an optical fiber preform

Patent metadata

Field	Value
Publication number	US-11713272-B2
Application number	US-202016799185-A
Country	US
Kind code	B2
Filing date	Feb 24, 2020
Priority date	Mar 5, 2019
Publication date	Aug 1, 2023
Grant date	Aug 1, 2023

Abstract

A system and methods are described herein for preheating a preform in a preheater furnace and then transferring the preheated preform to a consolidation furnace for chemical treatment and sintering the preform into a clear glass which can be drawn into optical fiber. In addition, the preheater furnace is described herein which is configured to heat the preform per a predetermined heat-profile until the preform is uniformly heated to a temperature above 1000° C.

First claim

The invention claimed is:

1. A method of processing an optical fiber preform, comprising:
loading a porous preform into a preheater furnace;
heating the porous preform in the preheater furnace to form a preheated preform, the preheated preform having an outer surface at a first temperature, the first temperature exceeding 1000° C.;
transferring the preheated preform from the preheater furnace to a consolidation furnace, wherein the preheater furnace is spaced apart and separate from the consolidation furnace, the outer surface of the preheated preform cooling to a second temperature during the transferring, the transferring including inserting the preheated preform with the outer surface at the second temperature into the consolidation furnace, the second temperature being greater than room temperature and less than the first temperature.

2. The method of claim 1 , wherein the porous preform has a bulk density in the range from 0.35 g/cm 3 -0.70 g/cm 3 .

3. The method of claim 1 , wherein the preheated preform has a surface density in the range from 0.35 g/cm 3 -0.70 g/cm 3 .

4. The method of claim 1 , wherein the first temperature is less than 1200° C.

5. The method of claim 1 , wherein the second temperature is greater than 600° C.

6. The method of claim 1 , wherein the second temperature is less than the first temperature by less than 600° C.

7. The method of claim 1 , wherein the preheated preform has a uniform temperature greater than 1000° C.

8. The method of claim 1 , further comprising rotating the porous preform in the preheater furnace.

9. The method of claim 1 , further comprising sintering the preheated preform in the consolidation furnace.

10. The method of claim 9 , further comprising doping or drying the preheated preform in the consolidation furnace.

11. The method of claim 1 , further comprising forming a consolidated preform from the preheated preform in the consolidation furnace, the consolidated preform having a bulk density greater than 1.90 g/cm 3 .

12. The method of claim 1 , wherein the transferring occurs in less than 10 min.

Assignees

• Corning Inc

Inventors

• Groh Raymond David
• Morse Joseph Leroy
• Shepard Bradley Kent
• Smith Ian Anthony
• Thornton Eric Wade

Classifications

• C03B37/01257 Primary

  Heating devices therefor · CPC title

• C03B37/0124

  Means for reducing the diameter of rods or tubes by drawing, e.g. for preform draw-down · CPC title

• C03B37/0126

  Means for supporting, rotating, translating the rod, tube or preform · CPC title

• F27B5/00

  Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated (furnaces through which the charge is moved mechanically or in which the charge moves by gravity F27B9/00) · CPC title

• F27B5/13

  Arrangement of devices for discharging · CPC title