Highly transmissive glasses with high solarisation resistance, use thereof and method for production thereof
Glasses are provided that are highly transparent and have very good resistance to solarisation. The resistance to solarisation is favoured to a special extent by the production method. The concentrations of reduced polyvalent ion species are reduced by targeted use of bubbling with an oxidising gas. Methods for producing glasses and to the uses thereof, particularly as core glasses in optical waveguides, are also provided.
1. An optical fiber comprising a core glass having improved solarization resistance, the core glass comprising SnO 2 , up to 2.8% by weight Al 2 O 3 , at most 33% by weight SiO 2 , and at least 12% by weight and at most 24% by weight of La 2 O 3 , the core glass having an attenuation of ≤1300 dB/km at a wavelength of 1050 nm, wherein the core glass is free of oxides of Bi, and free of Lu 2 O 3 , Gd 2 O 3 , Dy 2 O 3 and Yb 2 O 3 .
2. The optical fiber according to claim 1 , wherein the attenuation of the core glass at a wavelength of 1050 nm is <400 dB/km.
3. The optical fiber according to claim 1 , wherein the attenuation of the core glass at a wavelength of 1050 nm is 400 to 1300 dB/km.
4. The optical fiber according to claim 1 , wherein the core glass further comprises Fe 2+ and/or Fe 3+ in a content of 0 to 10 ppm.
5. The optical fiber according to claim 1 , wherein the core glass further comprises MnO in a concentration of <200 ppb.
6. The optical fiber according to claim 1 , wherein the core glass further comprises MnO in a concentration of 200 to 500 ppb.
7. The optical fiber according to claim 1 , wherein the core glass is free of PbO, As 2 O 3 and Sb 2 O 3 .
8. The optical fiber according to claim 1 , wherein the core glass further comprises a composition in percent by weight of:
from
to
B 2 O 3
0
24
SiO 2
23
62.1
Al 2 O 3
0
10
Li 2 O
0
10
Na 2 O
0
18.5
K 2 O
0
25.7
BaO
0
57.8
ZnO
0
40
La 2 O 3
0
25
ZrO 2
0
10
HfO 2
0
14.2
SnO 2
>0
2
MgO
0
8
CaO
0
8
SrO
0
24.4
Ta 2 O 5
0
22
Y 2 O 3
0
11.9
Rb 2 O
0
15
Cs 2 O
0
21
GeO 2
0
7.5
F
0
2
Σ R 2 O
5
20
Σ MgO, CaO, SrO, ZnO
20
42.
9. The optical fiber according to claim 8 , wherein the core glass further comprises a mass ratio of SiO 2 to B 2 O 3 that is more than 5.
10. The optical fiber according to claim 8 , wherein the core glass further comprises a total content of MgO, CaO, BaO, SrO, La 2 O 3 , Ta 2 O 5 , ZrO 2 and HfO 2 of at least 40% by weight.
11. The optical fiber according to claim 8 , wherein the core glass further comprises a portion of Sn 2+ of at most 5%, based on a total content of tin.
12. The optical fiber according to claim 1 , wherein the core glass further comprises a content of SnO 2 of at least 0.01 and at most 1% by weight.
13. A method for the production of the optical fiber of claim 1 , comprising the steps of:
melting the glass mixture in a melting vessel; and
refining the melt in a refining vessel.
14. The optical fiber according to claim 1 , further comprising a cladding glass sheathing the core glass.
15. The method according to claim 13 , further comprising the step of bubbling the melt in a conditioning vessel with an oxidizing gas after the refining step.
16. The optical fiber according to claim 1 , wherein the core glass comprises more Fe 3+ than Fe 2+ .
17. The optical fiber according to claim 1 , wherein the minimum content of HfO 2 in the core glass is 0.01% by weight.
18. A fiber glass having improved solarization resistance comprising SnO 2 , up to 2.8% by weight Al 2 O 3 , at most 33% by weight SiO 2 , and at least 12% by weight and at most 24% by weight of La 2 O 3 , the fiber glass having an attenuation of ≤1300 dB/km at a wave length of 1050 nm, wherein the refractive index of the fiber glass is between 1.55 and 1.75, and wherein the fiber glass is free of oxides of Bi, and free of Lu 2 O 3 , Gd 2 O 3 , Dy 2 O 3 and Yb 2 O 3 .
19. The fiber glass according to claim 18 , wherein the attenuation thereof at a wavelength of 1050 nm is <400 dB/km.
20. The fiber glass according to claim 18 , wherein the attenuation thereof at a wavelength of 1050 nm is 400 to 1300 dB/km.
21. An optical fiber comprising a core glass comprising the fiber glass according to claim 18 .