Glass optical waveguide with variable cross section

Patent metadata

Field	Value
Publication number	US-11999647-B2
Application number	US-202117460091-A
Country	US
Kind code	B2
Filing date	Aug 27, 2021
Priority date	Feb 28, 2019
Publication date	Jun 4, 2024
Grant date	Jun 4, 2024

Abstract

A drawn glass element for producing glass optical waveguides is provided. The element has two first length portions with a first cross-sectional area and which define the two ends of the glass element; a second, intermediate length portion between the two first length portions, which has a second cross-sectional area smaller than the first cross-sectional area; a first transition portion between the intermediate length portion and one of the first length portions; and a second transition portion between the intermediate length portion and another of the first length portions. The first and second transition portions have a cross-sectional area that steadily changes and merges from the first cross-sectional area into the second cross-sectional area.

First claim

What is claimed is:

1. A drawn glass element for producing glass optical waveguides, comprising:
two first length portions with a first cross-sectional area and which define the two ends of the glass element;
an intermediate length portion between the two first length portions, which has a second cross-sectional area smaller than the first cross-sectional area;
a first transition portion between the intermediate length portion and one of the first length portions; and
a second transition portion between the intermediate length portion and another of the first length portions, wherein the first and second transition portions have a cross-sectional area that steadily changes and merges from the first cross-sectional area into the second cross-sectional area,
wherein the first and second transition portions have a central third, wherein the central third has a cross section (A) that increases more slowly than a function

A
⁡

(
l
)

=

0
.
9

⁢
5
*

(

A
1

-

A
2

)

*

[

1
2

+

1
2

⁢

tanh
⁡

(

6
⁢

l
-

l
0

l
u

)

]

,

wherein l is a length coordinate in mm, A 1 is a first second cross-sectional area in mm 2 , A 2 is a second cross-sectional area mm 2 , l u is a length of the first and second transition portions in mm, and l 0 is a length coordinate of a midpoint of the first and second transition portion in mm.

2. The glass element of claim 1 , further comprising a maximum change in cross section per unit length (dA(l)/dl) in the first and/or second transition portions that is greater than (A 1 −A 2 )/l u and is less than 2.4·(A 1 −A 2 )/l u .

3. The glass element of claim 1 , further comprising a feature selected from a group consisting of: the second cross-sectional area being smaller than the first cross-sectional area by at least a factor of 1.2; the intermediate length portion having a length of at least three times a square root of the second cross-sectional area; a ratio of a cross-sectional area Q1 of the two first length portions to a cross-sectional area Q2 of the intermediate length portion that is in a range from 1.1 to 100; a ratio of a diameter D1 of the two first length portions to a diameter D2 of the intermediate length portion that is in a range from 1.1 to 10; a mean change in diameter in the first and second transition portions averaged over the length of the first and second transition areas that is in a range from 0.01 to 30; a mean change in diameter in the first and second transition portions averaged over the length of the first and second transition areas that is in a range from 0.01 to 3; a mean change in cross-sectional area (A) per unit length (I) in the first and second transition portions that is in a range from 8·10 −5 mm 2 /mm to 7·10 3 mm 2 /mm; a cross section A in a central third of the first and second transition portions that increases more slowly than the function

A
⁡
(
l
)

=

0.95
*

(

A
1

-

A
2

)

*

[

1
2

+

1
2

⁢

tanh
⁡
(

6
⁢

l
-

l
0

l
u

)

,

wherein l is the length coordinate in mm, A 1 is a first cross-sectional area and A 2 is a second cross-sectional area in mm 2 , l u is a length of first and second transition portions in mm, and l 0 is a length of a midpoint of the first and second transition portions in mm; a plurality of intermediate length portions; the first and second transition portions having different lengths; and any combinations thereof.

4. The glass element of claim 1 , wherein the intermediate length portion and the two first length portions have cross sections with a shape fitting in a smallest surrounding rectangle with an aspect ratio of at most 3:1.

5. The glass element of claim 1 , wherein the two first length portions and the intermediate length portions have a circular cross-sectional shape.

6. The glass element of claim 1 , wherein the intermediate length portion is arranged concentrically to at lea

Assignees

• Schott Ag

Inventors

• Steigleder Jan Philipp
• Schultheis Bernd
• Cramer Martin
• Schwedler Christian
• Russert Hubertus
• Hunzinger Bernhard
• Werner Holger

Classifications

• G02B6/0058

  varying in density, size, shape or depth along the light guide · CPC title

• C03B37/032 Primary

  for glass optical fibres · CPC title

• C03B23/047 Primary

  by drawing ({C03B23/091} , C03B37/025 takes precedence) · CPC title

• C03B37/02

  by drawing or extruding, {e.g. direct drawing of molten glass from nozzles; Cooling fins therefor (C03B37/04 takes precedence; sizing of the fibres C03C25/00)} · CPC title

• C03B37/15

  with heat application, e.g. for making optical fibres (fusion-splicing of light guides G02B6/255; treatment of light guides to shape optical elements {G02B6/2835, G02B6/2856}) · CPC title