Low loss optical fibers with fluorine and chlorine codoped core regions

Patent metadata

Field	Value
Publication number	US-9802858-B2
Application number	US-201615096821-A
Country	US
Kind code	B2
Filing date	Apr 12, 2016
Priority date	Apr 15, 2015
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A co-doped optical fiber is provided having an attenuation of less than about 0.17 dB/km at a wavelength of 1550 nm. The fiber includes a core region in the fiber having a graded refractive index profile with an alpha of greater than 5. The fiber also includes a first cladding region in the fiber that surrounds the core region. Further, the core region has an relative refractive index of about −0.10% to about +0.05% compared to pure silica. In addition, the core region includes silica that is co-doped with chlorine at about 1.2% or greater by weight and fluorine between about 0.1% and about 1% by weight.

First claim

What is claimed is:

1. A single mode optical fiber, comprising:
a fiber having an attenuation of less than about 0.17 dB/km at a wavelength of 1550 nm, the fiber comprising
a core region in the fiber having a graded refractive index profile with an alpha of greater than 5; and
a first cladding region in the fiber that surrounds the core region,
wherein the core region has an relative refractive index of about −0.10% to about +0.05% compared to pure silica, and
further wherein the core region comprises silica co-doped with chlorine at about 1.2% or greater by weight and fluorine between about 0.1% and about 1% by weight.

2. The fiber according to claim 1 , wherein the first cladding region comprises a depressed region having a relative refractive index that is lower than a relative refractive index of the core region.

3. The fiber according to claim 1 , wherein the core region comprises silica co-doped with fluorine and chlorine such that the sum of the fluorine and chlorine in weight percent divided by the fluorine in weight percent is greater than a factor of about 1.5.

4. The fiber according to claim 1 , wherein the core region has a fictive temperature of about 1400° C. or less.

5. The fiber according to claim 1 , wherein the core region has a fictive temperature of about 1200° C. or less.

6. The fiber according to claim 1 , wherein the core region comprises silica co-doped with chlorine and fluorine, the chlorine at about 2.5% or greater by weight.

7. The fiber according to claim 2 , wherein the relative refractive index of the depressed region is about 0.35% less than the relative refractive index of the core region.

8. The fiber according to claim 1 , wherein the relative refractive index difference between the core and the first cladding region is between 0.2%Δ and 0.5%Δ.

9. The fiber according to claim 1 , wherein the core region comprises silica co-doped with chlorine at about 1.5% or greater by weight and fluorine between about 0.1% and about 0.6% by weight.

10. The fiber according to claim 1 , wherein the first cladding region comprises a stiff outer portion and a remaining portion, and the viscosity at 1650° C. of the stiff outer portion is greater than the viscosity at 1650° C. of at least one of the core region and the remaining portion.

11. The fiber according to claim 10 , wherein the difference in viscosity at 1650° C. of the stiff outer portion of the first cladding region and any one of the core and the remaining portion of the first cladding region is ≧1×10 6 Poise and ≦1.6×10 8 Poise.

12. The fiber according to claim 1 , wherein the fiber is further characterized by a 22 m cable cutoff wavelength of less than 1530 nm.

13. The fiber according to claim 1 , wherein the fiber is further characterized by a 22 m cable cutoff wavelength of less than 1260 nm.

14. A single mode optical fiber, comprising:
a fiber having an attenuation of less than about 0.17 dB/km at a wavelength of 1550 nm, the fiber comprising
a core region in the fiber that comprises silica co-doped with fluorine and chlorine; and
a first cladding region in the fiber that surrounds the core region,
wherein the core region has a graded refractive index profile having an alpha of greater than 5,
wherein the first cladding region comprises a depressed region having a relative refractive index that is lower than a relative refractive index of the core region, and
wherein the core region comprises silica co-doped with fluorine and chlorine such that the sum of the fluorine and chlorine in weight percent divided by the fluorine in weight percent is greater than a factor of about 1.5.

15. The fiber according to claim 14 , wherein the core region has a fictive temperature of about 1400° C. or less.

16. The fiber according to claim 14 , wherein the core region has a fictive temperature of about 1200° C. or less.

17. The fiber according to claim 14 , wherein the core region comprises greater than about 1.5% by weight chlorine and between about 0.6% and about 0.1% by weight fluorine.

18. The fiber according to claim 14 , wherein the core region comprises silica co-doped with chlorine and fluorine, the chlorine at about 2.5% or greater by weight.

19. The fiber according to claim 14 , wherein the relative refractive index of the depressed region is about 0.35% less than the relative refractive index of the core region.

20. The fiber according to claim 14 , wherein the fiber is further characterized by a 22 m cable cutoff wavelength of less than 1530 nm.

21. The fiber according to claim 14 , wherein the fiber is further characterized by a 22 m cable cutoff wavelength of less than 1260 nm.

22. A few-moded optical fiber, comprising:
a core region in the fiber that comprises silica co-doped with fluorine and chlorine, the core region having an relative refractive index of about −0.10% to about +0.05% compared to pure silica, and a radius of about 6.0 microns to about 50 microns, wherein the core region is configured to transmit optical data in greater than 2 and less than 8 modes at a wavelength of 1550 nm; and
a first cladding region in the fiber that surrounds the core region,
wherein the first cladding region comprises a depressed region having a relative refractive index that is lower than a relative refractive index of the core region,
further wherein the fiber has an attenuation of less than about 0.17 dB/km at a wavelength of 1550 nm, and
wherein the core region comprises silica co-doped with fluorine and chlorine such that the sum of the fluorine and chlorine in weight percent divided by the fluorine in weight percent is greater than a factor of about 1.5.

23. The fiber according to claim 22 , wherein the core region has a fictive temperature of about 1400° C. or less.

24. The fiber according to claim 22 , wherein the core region has a fictive temperature of about 1200° C. or less.

25. The fiber according to claim 22 , wherein the core region comprises silica co-doped with chlorine and fluorine at about 1.4% or greater and between about 1% and about 0.1% by weight, respectively.

26. The fiber according to claim 22 , wherein the core region silica co-doped with chlorine and fluorine, the chlorine at 2.5% or greater by weight.

27. The fiber according to claim 22 , wherein the first cladding region further comprises a stiff outer portion, and the viscosity at 1650° C. of the stiff outer portion is greater than the viscosity at 1650° C. of at least one of the core region and the depressed region.

28. The fiber according to claim 27 , wherein the difference in viscosity at 1650° C. of the stiff outer portion of the first cladding region and any one of the core and the depressed region of the first cladding region is ≧1×10 6 Poise and ≦1.6×10 8 Poise.

29. The fiber according to claim 1 , wherein the core region is substantially free of alkali.

30. The fiber according to claim 14 , wherein the core region is substantially free of alkali.

31. The fiber according to claim 22 , wherein the core region is substantially free of alkali.

Assignees

• Corning Inc

Inventors

• Bookbinder Dana Craig
• Li Ming-Jun
• Tandon Pushkar

Classifications

• G02B6/03683

  arranged - - + + · CPC title

• G02B6/03655

  arranged - + + · CPC title

• C03C2201/12

  containing fluorine (C03C2201/14 takes precedence) · CPC title

• C03C13/045

  Silica-containing oxide glass compositions · CPC title

• G02B6/03627

  arranged - + · CPC title