Low loss single mode fiber with chlorine doped core

Patent metadata

Field	Value
Publication number	US-10094975-B2
Application number	US-201715659955-A
Country	US
Kind code	B2
Filing date	Jul 26, 2017
Priority date	Jul 29, 2016
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

An optical fiber comprising: (i) a chlorine doped silica based core comprising a core alpha (α)>10, and maximum refractive index delta Δ 1max % and Cl concentration >1 wt %; (ii) a cladding surrounding the core, the cladding comprising: (a) an inner cladding region adjacent to and in contact with the core and having a refractive index delta Δ 2 and a minimum refractive index delta Δ 2min such that Δ 2min <Δ 1max , the inner cladding region comprising fluorine doped silica and the refractive index delta Δ 2 with region that decreases with radial position, and (b) an outer cladding region surrounding the inner cladding region and having refractive index delta Δ 3 , such that Δ 2min <Δ 3 . The fiber has mode field diameter MFD at 1310 nm of ≥9 microns, a cable cutoff of ≤1260 nm, zero dispersion wavelength of 1300 nm≤zero dispersion wavelength ≤1324 nm and bend loss at 1550 nm for a 20 mm mandrel of less than 0.5 dB/turn.

First claim

What is claimed is:

1. An optical fiber comprising:
(i) a chlorine doped silica based core comprising a core alpha (α core )>10, a maximum refractive index delta Δ 1max %, and Cl concentration >1 wt %;
(ii) a cladding surrounding the core, the cladding comprising:
a. an inner cladding region comprising fluorine doped silica, adjacent to and in contact with the core and having a refractive index delta Δ 2 and a minimum refractive index delta Δ 2min such that Δ 2min <Δ 1max , the refractive index delta Δ 2 of the inner cladding region comprising a region that decreases with radial position, and
b. an outer cladding region surrounding the inner cladding region and having refractive index delta Δ 3 , such that Δ 2min <Δ 3 ;

wherein the optical fiber has mode field diameter MFD at 1310 nm of ≥9 microns, a cable cutoff of ≤1260 nm, zero dispersion wavelength such that 1300 nm≤zero dispersion wavelength ≤1324 nm, and bend loss at 1550 nm for a 20 mm mandrel of less than 0.5 dB/turn.

2. The optical fiber according to claim 1 , wherein the core alpha is at least 20.

3. The optical fiber according to claim 1 , wherein the core alpha is at least 50.

4. The optical fiber according to claim 1 , wherein the core alpha is at least 100.

5. The optical fiber according to claim 1 wherein the refractive index delta Δ 2 of the inner cladding region monotonically decreases radially, towards the outer cladding region.

6. The optical fiber according to claim 1 wherein the core has an outer radius r 1 and 3.0 micron≤r 1 ≤6.0 micron.

7. The optical fiber according to claim 1 , wherein 3.3 micron≤r 1 ≤4.5 micron.

8. The optical fiber according to claim 1 , wherein inner cladding region has a maximum refractive index delta Δ 2max , and wherein Δ 3 is <Δ 2max .

9. The optical fiber according to claim 1 , wherein the the inner cladding has a Trench Slope TS=(Δ 2max −Δ 2min )/(r 2 −r 1 ), of 0.005% Δ/micron<TS<0.2% Δ/micron.

10. The optical fiber according to claim 1 , wherein the inner cladding has an alpha value α T , and 0.2<Δ T <5.

11. The optical fiber of claim 1 , wherein the core has chlorine concentration of greater than 1.2 wt %.

12. The optical fiber of claim 1 , wherein the core has chlorine concentration of greater than 3 wt %.

13. The optical fiber of claim 1 , wherein the outer cladding region is surrounded by a silica outer layer.

14. The optical fiber of claim 1 , wherein Δ 1max is between 0.1% and 0.5%.

15. The optical fiber of claim 1 , wherein Δ 2min is between −0.35% and 0.05%.

16. The optical fiber of claim 1 , wherein Δ 3 is between −0.3% and 0.1%.

17. The optical fiber of claim 1 , wherein the attenuation at 1550 nm is less than 0.17 dB/km.

18. The optical fiber of claim 1 , wherein the core has a radius r 1 such that 3 micron≤r 1 ≤4.5 micron; and 0.1%≤Δ 1max ≤0.35%; the inner cladding region has an outer radius r 2 and 6 micron≤r 2 ≤18 micron; −0.35%≤Δ 2min <0.0%.

19. The optical fiber of claim 18 , wherein the inner cladding region has a volume between 3% Δmicron 2 and 12% Δmicron 2 .

20. The optical fiber of claim 18 , wherein the bend loss at 1550 nm for a 20 mm mandrel is less than 0.3 dB/turn.

21. The optical fiber of claim 18 , wherein MFD at 1310 nm is between 9 microns and 9.6 microns.

22. The optical fiber according to claim 1 , wherein the refractive index delta Δ 2 of the portion of the inner cladding region that decreases with radial position is offset from the core.

23. The optical fiber according to claim 1 , wherein the offset is 1 micron≤offset≤15 microns.

Assignees

• Corning Inc

Inventors

• Bookbinder Dana Craig
• Li Ming-Jun
• Mishra Snigdharaj Kumar
• Tandon Pushkar

Classifications

• G02B6/02009

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

• G02B6/03633

  arranged - - · CPC title

• G02B6/03627

  arranged - + · CPC title

• G02B6/03655

  arranged - + + · CPC title

• G02B6/03616

  Optical fibres characterised both by the number of different refractive index layers around the central core segment, i.e. around the innermost high index core layer, and their relative refractive index difference · CPC title