Optical glass fibers, apparatus and preparation using reactive vapor transport and deposition

Abstract

A new method for preparing low loss multimode and monomode glass optical fibers which avoids casting or pouring the core and clad melts is disclosed. The new technique is based on a reactive-gas-transport approach which avoids contamination from absorbing impurities and scattering centers by reacting the glass melt with reactive gases which remove impurities and increase the refractive index of the fiber.

Claims

1. A process for the production of glass fibers, the steps of which comprise;

placing a glass fiber starting material into a rotating mold;

heating said glass fiber starting material in said mold to a temperature sufficient to cause said material to melt;

rotating said mold at a rate sufficient to cause said starting material to form a hollow tube inside said mold;

purging said glass fiber starting material with one or more reactive gases to remove hydroxides, water, and other impurities;

blowing one or more reactive gases through said mold, said gases reacting with said melt to increase the refractive index;

rapidly quenching said mold to the glass transition temperature to form a glass fiber preform; and

drawing said preform into a glass fiber.

2. The process of claim 1 wherein the step of placing said glass fiber starting material into said rotating mold comprises placing said glass fiber starting material selected from the group consisting of fluoride, chloride, bromide, fluorophosphate, and mixed halide glasses into said mold.

3. The process of claim 2 wherein the step of placing said glass fiber starting material into said rotating mold comprises placing said glass fiber starting material selected from the group consisting of fluoride, chloride, bromide glasses into said mold.

4. The process of claim 3 wherein the step of placing said glass fiber starting material into said rotating mold comprises placing fluoride glass into said mold.

5. The process of claim 1 wherein said heating step comprises heating said glass fiber starting material to a temperature between about 500.degree.-1000.degree..

6. The process of claim 1 wherein said purging step comprises purging said glass fiber starting material with reactive gases selected from the group consisting of SF.sub.6, NF.sub.3, F.sub.2, and CF.sub.4.

7. The process of claim 2 wherein said blowing step comprises blowing reactive gases selected from the group consisting of HCl, HBr, HI, Cl.sub.2, Br.sub.2, I.sub.2, SnI.sub.2 +Ar, BiI.sub.3 +Ar, SnBr.sub.2 +Ar, BiBr.sub.3 +Ar, BiF.sub.3 +Ar, PF.sub.5 +Br.sub.2, and PF.sub.5 +Cl.sub.2 through said mold.

8. The process of claim 7 wherein said said blowing step comprises blowing reactive gases selected from the group consisting of HCl, HBr, HI, Cl.sub.2, Br.sub.2, and I.sub.2 through said mold.

9. A process for the production of glass fibers, the steps of which comprise;

heating a glass fiber starting material to a temperature sufficient to cause said material to sublime;

transporting said material to a cold rotating mold using an inert carrier gas;

cooling said material thereby causing said material to deposit on the inner surface of said mold;

halogenating said materials to produce a glass fiber material;

heating said material to a temperature above said glass fiber materials melting point;

purging said material with reactive gases;

blowing one or more reactive gases through said mold, said gases reacting with said melt to increase the refractive index;

rapidly quenching said mold to the glass transition temperature to form a glass fiber preform; and

drawing said preform into a glass fiber.

10. The process of claim 9 wherein said heating step comprises heating said glass fiber starting material selected from the group consisting of metal chlorides, metal bromides, metal iodines, and organo-metallic compounds.

11. The process of claim 10 wherein said heating step comprises heating said glass fiber starting material selected from the group consisting of such as ZrCl.sub.4, ZrCl.sub.2, ZrCl.sub.3, ZrBr.sub.2, ZrBr.sub.3, ZrBr.sub.4, ZrI.sub.4, Ba (C.sub.10 H.sub.19 O.sub.2), BaI.sub.2, AlCl.sub.3, AlBr.sub.3, Al (sec-butoxide), LaI.sub.3, PbBr.sub.2, and LiNH.sub.2.

12. The process of claim 9 wherein said heating step comprises heating said glass fiber starting material to a temperature between about 500.degree.-1000.degree..

13. The process of claim 9 wherein said halogenating step comprises reacting said glass fiber starting material with a halogen gas, said halogen in said halogen gas having a higher molecular weight than the halogen in the glass.

14. The process of claim 9 wherein said purging step comprises purging said glass fiber starting material with reactive gases selected from the group consisting of SF.sub.6, NF.sub.3, F.sub.2, and CF.sub.4.

15. The process of claim 9 wherein said blowing step comprises blowing reactive gases selected from the group consisting of HCl, HBr, HI, Cl.sub.2, Br.sub.2, I.sub.2, SnI.sub.2 +Ar, BiI.sub.3 +Ar, SnBr.sub.2 +Ar, BiBr.sub.3 +Ar, BiF3+Ar, PF.sub.5 +Br.sub.2, and PF.sub.5 +Cl.sub.2 through said mold.

16. The process of claim 15 wherein said blowing step comprises blowing reactive gases selected from the group consisting of HCl, HBr, HI, Cl.sub.2, Br.sub.2, and I.sub.2 through said mold.

17. An apparatus for producing glass optical fibers, comprising:

a rotating mold for containing a glass melt, said mold having gas entry and gas exit ports;

means for rotating said mold;

means for heating said mold to a temperature sufficient to produce said glass melt; and

means for supplying gases to said mold through said gas entry port.

18. The apparatus of claim 17 wherein said rotating mold is made from a material selected from the group consisting of platinum, gold, graphite, or vitreous carbon.

19. The apparatus of claim 17 wherein said means for heating said mold is heating rods, said heating rods being capable of heating said mold to a temperature between 500.degree.-1000.degree. C.

20. The apparatus of claim 19 wherein said means for supplying gases to said mold comprises a plurality of bubblers from which reactive gases or liquid vapors and glass optical fiber starting materials can be transported to said mold by a carrier gas, said bubblers having a heating means for controlling the temperature of said bubblers.

21. The apparatus of claim 20 wherein said heating means for controlling the temperature of said bubblers is selected from the group consisting of heating tape and heating mattles.

22. The product of the process of claim 1.

23. The product of the process of claim 9.