Glass fibers and pre-forms made of homogeneous quartz glass

Patent metadata

Field	Value
Publication number	US-10676388-B2
Application number	US-201616061122-A
Country	US
Kind code	B2
Filing date	Dec 16, 2016
Priority date	Dec 18, 2015
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

One aspect relates to a light guide comprising a jacket and one or more cores, wherein the jacket surrounds the cores. Each core has a refractive index profile perpendicular to the maximum extension of the core, wherein at least one refractive index n K of each refractive index profile is greater than the refractive index n M1 of the jacket. The jacket is made of silicon dioxide and has an OH content of less than 10 ppm, a chlorine content of less than 60 ppm, and an aluminium content of less than 200 ppb. One aspect also relates to a silicon dioxide granulate I, characterized by a chlorine content of less than 200 ppm and an aluminium content of less than 200 ppb, in each case based on the total weight of the silicon dioxide granulate I.

First claim

The invention claimed is:

1. A light guide comprising:
a jacket; and
one or more cores;
wherein the jacket surrounds the cores;
wherein each core has a refractive index profile perpendicular to the maximum core extension, wherein at least one refractive index n K of each refractive index profile is greater than the refractive index n M1 of the jacket;
wherein the jacket is made of silicon dioxide and comprises:
an OH content of less than 10 ppm;
a chlorine content of less than 60 ppm; and
an aluminium content of less than 200 ppb;

wherein the ppb and ppm are each based on the total weight of the jacket M1.

2. The light guide according to claim 1 , comprising two or more cores, wherein the jacket surrounds the cores as a matrix.

3. The light guide according to claim 1 , wherein the jacket comprises at least one of:
an ODC content of less than 5×10 15 /cm 3 ;
a metal content of metals different to aluminium of less than 1 ppm;
a viscosity (p=1013 hPa) in a range from log 10 (η(1200° C.)/dPas)=13.4 to log 10 (η(1200° C.)/dPas)=13.9 or log 10 (η(1300° C.)/dPas)=11.5 to log 10 (1300° C.)/dPas)=12.1 or log 10 (η(1350° C.)/dPas)=1.2 to log 10 (η(1350° C.)/dPas)=10.8;
a curl parameter of more than 6 m;
a standard deviation of the OH content of not more than 10%, based on the OH content of the jacket;
a standard deviation of the Cl content of not more than 10%, based on the Cl content of the jacket;
a standard deviation of the Al content of not more than 10%, based on the Al content of the jacket;
a refractive index homogeneity of less than 1×10 −4 ; and
a transformation point T g in a range from 1150 to 1250° C.,
wherein the ppb and ppm are each based on the total weight of the jacket.

4. The light guide according to claim 1 , wherein the content by weight of the jacket is at least 60 wt.-%, based on the total weight of the cores and the jacket.

5. A process for the preparation of a light guide, comprising:
providing:
a quartz glass body,
wherein the quartz glass body is made of silicon dioxide, wherein the silicon dioxide comprises:
an OH content of less than 10 ppm;
a chlorine content of less than 60 ppm; and
an aluminium content of less than 200 ppb;
 wherein the ppb and ppm are each based on the total weight of the quartz glass body

wherein the quartz glass body is first processed obtaining a hollow body with at least one opening;

introducing one or multiple core rods into the quartz glass body through the at least one opening to obtain a precursor; and
drawing the precursor in the warm to obtain the light guide with one or more cores and a jacket.

6. A light guide obtainable by the process of claim 5 .

7. The light guide according to claim 6 , wherein the light guide has a jacket and one or multiple cores,
wherein the jacket surrounds the cores,
wherein each core has a refractive index profile perpendicular to the maximum extension of the core, wherein at least one refractive index n K of each refractive index profile is greater than the refractive index n M1 of the jacket;
wherein the jacket is made of silicon dioxide and comprises
an OH content of less than 10 ppm; and
a chlorine content of less than 60 ppm; and
an aluminium content of less than 200 ppb;
wherein the ppb and ppm are each based on the total weight of the jacket.

8. A light guide cable comprising at least two light guides according to claim 1 .

9. A process for the preparation of a light guide cable comprising:
providing at least two light guides according to claim 1 ; and
processing the at least two light guides from to obtain a light guide cable.

10. The quartz glass body according to claim 5 , further comprising at least one of the following:
an ODC content of less than 5×10 15 /cm 3 ;
a metal content of metals which are different to aluminium of less than 300 ppb;
a viscosity (p=1013 hPa) in a range from log 10 (η(1200° C.)/dPas)=13.4 to log 10 (η(1200° C.)/dPas)=13.9 or log 10 (η(1300° C.)/dPas)=11.5 to log 10 (η(1300° C.)/dPas)=12.1 or log 10 (η(1350° C.)/dPas)=1.2 to log 10 (η(1350° C.)/dPas)=10.8;
a standard deviation of the OH content of not more than 10%, based on the OH content of the quartz glass body;
a standard deviation of the Cl content of not more than 10%, based on the Cl content of the quartz glass body;
a standard deviation of the Al content of not more than 10%, based on the Al content of the quartz glass body;
a refractive index homogeneity of less than 1×10 −4 ;
a cylindrical form;
a transformation temperature T g in a range from 1150 to 1250° C.; and
a fictive temperature in a range from 1055 to 1200° C.;
wherein the ppb and ppm are each based on the total weight of the quartz glass body.

Assignees

• Heraeus Quarzglas

Inventors

• Hünermann Michael
• Hofmann Achim
• Fabian Heinz
• Otter Matthias
• Kayser Thomas

Classifications

• C03C2213/00

  Glass fibres or filaments · CPC title

• C03C2201/23

  containing hydroxyl groups · CPC title

• C03B37/01211

  by inserting one or more rods or tubes into a tube · CPC title

• C03C2201/32

  containing aluminium (C03C2201/36 takes precedence) · CPC title

• G02B6/02395

  Glass optical fibre with a protective coating, e.g. two layer polymer coating deposited directly on a silica cladding surface during fibre manufacture (G02B6/02052, G02B6/02057, G02B6/024, G02B6/032, G02B6/105, G02B6/14 take precedence; coating on fibre gratings G02B6/02104; multilayer core or cladding G02B6/036; reinforcing splice joints G02B6/2558; optical cables, i.e. comprising protective structures external to the protective coating such as a jacket or plural coated optical fibres G02B6/44; coating of glass to obtain optical fibres C03C25/104) · CPC title