Low bend loss single mode optical fiber with chlorine updoped cladding

Patent metadata

Field	Value
Publication number	US-10048438-B2
Application number	US-201715708438-A
Country	US
Kind code	B2
Filing date	Sep 19, 2017
Priority date	Sep 15, 2015
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

An optical fiber having both low macrobend loss and low microbend loss. The fiber has a central core region, a first (inner) cladding region surrounding the central core region and having an outer radius r2>16 microns and relative refractive index Δ2, and a second (outer) cladding region surrounding the first cladding region having relative refractive index, Δ3, wherein Δ1>Δ3>Δ2. The difference between Δ3 and Δ2 is greater than 0.12 percent. The fiber exhibits a 22 m cable cutoff less than or equal to 1260 nm, and r1/r2 is greater or equal to 0.24 and bend loss at 1550 nm for a 15 mm diameter mandrel of less than 0.5 dB/turn.

First claim

What is claimed is:

1. An optical fiber comprising:
(i) a central core region having outer radius r 1 and refractive index Δ 1
(ii) a cladding surrounding the central core region, the cladding comprising:
(a) a first cladding region having an outer radius 25 microns>r 2 >16 microns and relative refractive index Δ 2 , wherein the ratio of r 1 /r 2 is larger than 0.24 and
(b) a second cladding region surrounding the first cladding region and having a relative refractive index Δ 3 and an outer radius r 3 , wherein the second cladding region comprises at least 1.25 wt % chlorine (Cl), and wherein Δ 1 >Δ 3 >Δ 2 , and wherein the difference between Δ 3 and Δ 2 is greater than 0.12%, and Δ 3 >0.12%;

and said fiber exhibits a bend loss at 1550 nm for a 15 mm diameter mandrel of less than 0.5 dB/turn.

2. The optical fiber of claim 1 , wherein the difference between Δ 3 and Δ 2 is greater than 0.13%.

3. The optical fiber of claim 1 , wherein the difference between Δ 3 and Δ 2 is between 0.12% and 0.25%.

4. The optical fiber of claim 1 , wherein said fiber exhibits a 22 m cable cutoff less than or equal to 1260 nm.

5. The optical fiber of claim 1 , wherein the central core region of said fiber exhibits an alpha less than 10.

6. The optical fiber of claim 1 , said fiber further exhibiting a wire mesh covered drum microbend loss at 1550 nm which is less than or equal to 0.07 dB/km.

7. The optical fiber of claim 1 , wherein the first cladding region contains less than 0.02 wt % fluorine.

8. The optical fiber of claim 1 , wherein the first cladding region is essentially free of fluorine and germania.

9. The optical fiber of claim 1 , wherein Δ 3 >Δ 2 for a length extending from r 2 to a radius of at least 30 microns.

10. The optical fiber of claim 1 , wherein the volume of the first cladding region is |V 2 |>30% □micron 2 .

11. The fiber of claim 1 , wherein said fiber exhibits an attenuation at 1550 nm which is less than or equal to 0.186 dB/km.

12. The optical fiber of claim 1 , wherein said central core region comprises a maximum relative refractive index (Δ 1 ) of greater than or equal to 0.70%.

13. The optical fiber of claim 1 , wherein the central core region of said fiber exhibits an alpha greater than or equal to 0.5 and less than or equal to 10.

14. The fiber of claim 1 , wherein the optical fiber exhibits:
1200 nm ≤cable cutoff wavelength ≤1260 nm;
1300 nm ≤zero dispersion wavelength ≤1324 nm;
0.7 dB/turn <macrobend loss at 10 mm bend diameter <1.3 dB/turn;
0.1 dB/turn <macrobend loss at 15 mm bend diameter<0.5 dB/turn;
0.05 dB/turn <macrobend loss at bend 20 mm diameter <0.20 dB/turn;
0.1 dB/turn <macrobend loss at 30 mm bend diameter <0.2 dB/turn;
wherein the macrobend loss is measured at 1550 nm wavelength.

15. The optical fiber of claim 1 , wherein the volume of the first cladding region is |V 2 |>60% Δ micron 2 .

16. The optical fiber comprising:
(i) a central core region having outer radius r 1 and refractive index Δ 1
(ii) a cladding surrounding the central core region, the cladding comprising:
(a) a first cladding region having an outer radius 25 microns>r 2 >16 microns and relative refractive index Δ 2 , wherein the ratio of r 1 /r 2 is larger than 0.24 and
(b) a second cladding region surrounding the first cladding region and having a relative refractive index Δ 3 and an outer radius r 3 , wherein the second cladding region comprises at least 1.25 wt % chlorine (Cl), and wherein Δ 1 >Δ 3 >Δ 2 , and wherein the difference between Δ 3 and Δ 2 is greater than 0.12%, and Δ 3 >0.12%;

and said fiber exhibits a bend loss at 1550 nm for a 15 mm diameter mandrel of less than 0.5 dB/turn, said fiber having a coating thereon and exhibiting a basketweave microbend loss at −60° C. at 1550 nm which is less than or equal to 0.05 dB/km.

17. The optical fiber of claim 16 , wherein said fiber exhibits a 22 m cable cutoff less than or equal to 1260 nm.

18. An optical fiber comprising:
(i) a central core region having outer radius r 1 and refractive index Δ 1 ;
(ii) a cladding surrounding the central core region, the cladding comprising:
(a) a first cladding region having an outer radius 25 microns>r 2 >16 microns and relative refractive index Δ 2 , wherein the ratio of r 1 /r 2 is larger than 0.24, and
(b) a second cladding region surrounding the first cladding region and having a relative refractive index Δ 3 and an outer radius r 3 , wherein the second cladding region comprises at least 1.2 wt % chlorine (Cl), and wherein Δ 1 >Δ 3 >Δ 2 , and wherein the difference between Δ 3 and Δ 2 is greater than 0.12%, and Δ 3 >0.12%;

said fiber exhibits a bend loss at 1550 nm for a 15 mm diameter mandrel of less than 0.5 dB/turn said fiber further comprising a third cladding region surrounding the second cladding region, the third region having a refractive index Δ 4 , wherein Δ 3 >Δ 4 , and wherein the difference between Δ 3 and Δ 4 is greater than 0.1%, and −0.02<Δ4 <0.02.

19. The optical fiber of claim 18 , wherein the third cladding region includes less chlorine than the second cladding region, or no chlorine.

20. The optical fiber of claim 19 wherein, the third cladding region has viscosity that is larger than the viscosity of the second cladding region by at least 0.1×107 Poise.

21. The optical fiber of claim 18 , wherein the third cladding region includes less than 1 wt % of chlorine.

22. The optical fiber of claim 18 , wherein said fiber exhibits a 22 m cable cutoff less than or equal to 1260 nm.

23. The optical fiber of claim 22 , wherein the second cladding region comprises at least 1.3 wt % chlorine (Cl).

24. The optical fiber of claim 22 , said fiber further exhibiting a basketweave microbend loss at −60° C. at 1550 nm which is less than or equal to 0.01 dB/km.

25. The optical fiber of claim 22 , said fiber further exhibiting a basketweave microbend loss at −60° C. at 1625 nm which is less than or equal to 0.05 dB/km.

26. The optical fiber of claim 22 , said fiber further exhibiting a basketweave microbend loss at −60° C. at 1625 nm which is less than or equal to 0.01 dB/km.

27. The optical fiber of claim 22 , wherein said coating comprises: a primary coating P having a Young's modulus 0.1 to 1 MPa; and a secondary coating S having a Young's modulus of 1400 MPa to 2500 MPa, wherein the secondary coating has an outer coating diameter of not greater than 242 microns.

28. The fiber of claim 1 , wherein the optical fiber exhibits:
MFD at 1310 nm >9 microns;
cable cutoff wavelength ≤1260 nm;
zero dispersion wavelength, □0, of 1300 nm ≤□0 ≤1324 nm;
bend loss at 10 mm diameter <1.5 dB/turn;
bend loss at 15 mm diameter <0.5 dB/turn
wherein the bend loss is macrobend loss and is measured at 1550 nm wavelength.

29. The fiber of claim 28 , wherein said fiber exhibits a wire mesh covered drum macrobend loss at 1550 nm which is less than or equal to 0.07 dB/km.

30. The fiber of claim 28 , wherein said fiber exhibits an attenuation at 1550 nm which is less than or equal to 0.18 dB/km.

Assignees

• Corning Inc

Inventors

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

Classifications

• G02B6/02009

  Large effective area or mode field radius, e.g. to reduce nonlinear effects in single mode fibres · CPC title

• G02B6/03644

  arranged - + - · 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

• G02B6/0281

  Graded index region forming part of the central core segment, e.g. alpha profile, triangular, trapezoidal core (G02B6/0288, G02B6/0286 take precedence) · CPC title

• G02B6/02004

  characterised by the core effective area or mode field radius · CPC title