Low diameter optical fiber

Patent metadata

Field	Value
Publication number	US-11009656-B2
Application number	US-201815918352-A
Country	US
Kind code	B2
Filing date	Mar 12, 2018
Priority date	Apr 15, 2013
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

Small-radius coated optical fibers having large mode field diameter and low bending losses. The coated fiber may have an outer radius of 110 μm or less, while providing a mode field diameter of 9.0 μm or greater and a bending loss when wrapped about a 15 mm mandrel of 0.5 dB/km or less at wavelength of 1550 nm. The coated fiber may have a mode field diameter of 9.2 μm or greater and may have a bending loss at 1550 nm of 0.25 dB/km or less when wrapped about a 20 mm mandrel or a bending loss at 1550 nm of 0.02 dB/km or less when wrapped about a 30 mm mandrel.

First claim

What is claimed is:

1. A single-mode optical fiber comprising:
a core, said core having an outer radius r 1 ;
a cladding surrounding said core, said cladding having an outer radius r 4 , said cladding including a depressed index region, said depressed index region having a triangular relative refractive index profile with a moat volume with a magnitude less than 75% μm 2 ;
a primary coating surrounding said cladding, said primary coating having an outer radius r 5 , said primary coating having an in situ modulus of 0.50 MPa or less; and
a secondary coating surrounding said primary coating, said secondary coating having an outer radius r 6 , said secondary coating having an in situ modulus of 1500 MPa or greater;
wherein said outer radius r 6 is 110 μm or less and said single-mode optical fiber has a mode field diameter 9.1 μm or greater at 1310 nm, a cable cutoff wavelength of 1260 nm or less, a zero dispersion wavelength λ 0 in the range 1300 nm≤λ 0 ≤1324 nm, a MAC number greater than 7.4 at 1310 nm, and said single-mode optical fiber exhibits a bend loss at a wavelength of 1550 nm, when turned about a mandrel having a diameter of 15 mm, of less than 0.5 dB/turn.

2. The fiber of claim 1 ,
wherein said cladding includes an inner cladding region having an outer radius r 3 and an outer cladding region surrounding said inner cladding region and having said outer radius r 4 , said inner cladding region having a refractive index Δ 3 with a minimum value Δ 3MIN , said outer cladding region having a refractive index Δ 4 with a minimum value Δ 4MIN >Δ 3MIN .

3. The fiber of claim 2 , wherein said inner cladding region is directly adjacent to said core and said refractive index Δ 3 is substantially constant between said outer radius r 1 and said outer radius r 3 .

4. The fiber of claim 2 , wherein said inner cladding region is directly adjacent to said core, said refractive index Δ 3 decreasing linearly between said outer radius r 1 and said outer radius r 3 .

5. The fiber of claim 4 , wherein said outer cladding region is directly adjacent said inner cladding region and said refractive index Δ 4 is substantially constant between said outer radius r 3 and said outer radius r 4 .

6. The fiber of claim 1 , wherein said cladding includes a first inner cladding region having an outer radius r 2 , a second inner cladding region surrounding said first inner cladding region and having an outer radius r 3 , and an outer cladding region surrounding said second inner cladding region and having said outer radius r 4 , said first inner cladding region having a refractive index Δ 2 with a minimum value Δ 2MIN , said second inner cladding region having a refractive index Δ 3 with a minimum value Δ 3MIN <Δ 2MIN , said outer cladding region having a refractive index Δ 4 with a minimum value Δ 4MIN >Δ 3MIN .

7. The fiber of claim 6 , wherein second inner cladding region is directly adjacent said first inner cladding region and said refractive index Δ 3 is substantially constant between said outer radius r 2 and said outer radius r 3 .

8. The fiber of claim 6 , wherein second inner cladding region is directly adjacent said first inner cladding region and said refractive index Δ 3 decreases linearly between said outer radius r 2 and said outer radius r 3 .

9. The single-mode optical fiber of claim 1 , wherein said outer radius r 4 is at least 60 μm.

10. The single-mode optical fiber of claim 1 , wherein said outer radius r 5 is 85 μm or less.

11. The single-mode optical fiber of claim 1 , wherein said outer radius r 6 is 100 μm or less.

12. The single-mode optical fiber of claim 1 , wherein said single-mode optical fiber exhibits a bend loss at a wavelength of 1550 nm, when turned about a mandrel having a diameter of 20 mm, of less than 0.25 dB/turn.

13. The single-mode optical fiber of claim 1 , wherein said primary coating has an in situ modulus of 0.20 MPa or less.

14. The single-mode optical fiber of claim 1 , wherein said secondary coating has an in situ modulus of 1800 MPa or greater.

15. The fiber of claim 1 , wherein said primary coating has a glass transition temperature of less than −15° C.

16. The fiber of claim 1 , wherein said primary coating has a glass transition temperature higher than −50° C.

17. The fiber of claim 1 , wherein said primary coating has a glass transition temperature higher than −60° C.

18. The fiber of claim 1 , wherein said primary coating is the cured product of a primary composition that includes a urethane acrylate oligomer and a monomer selected from the group consisting of (meth)acrylates, N-vinyl amides, and epoxy acrylates.

19. The fiber of claim 18 , wherein said primary composition comprises one or more monofunctional (meth)acrylate monomers in an amount of from about 5 to 95% by weight; an N-vinyl amide monomer in an amount of from about 0.1 to 40% by weight; and one or more difunctional urethane acrylate oligomers which comprise a polyol and an isocyanate, said oligomer present in an amount of from about 5 to 95% by weight, wherein the polyol in said oligomer is a polypropylene glycol and the isocyanate in said oligomer is an aliphatic diisocyanate.

20. The fiber of claim 18 , wherein said primary composition comprises one or more monofunctional (meth)acrylate monomers in an amount of from about 40 to 65% by weight; an N-vinyl amide monomer in an amount of from about 2 to 10% by weight; and one or more polypropylene glycol-based difunctional urethane acrylate oligomers in an amount of from about 35 to 60% by weight.

21. The fiber of claim 1 , wherein said secondary coating is the cured product of a secondary composition that lacks urethane-containing oligomers.

22. The fiber of claim 21 , wherein said secondary composition comprises a monomer selected from the group consisting of alkoxylated bisphenol-A diacrylate, alkylene glycol acrylate, and epoxy diacrylate.

23. The fiber of claim 22 , wherein said secondary composition comprises:
about 40 to 80% by weight of ethoxylated (4) bisphenol A monomer;
from about 0 to about 30% by weight of ethoxylated (10) bisphenol A monomer;
from about 0 to about 25% by weight of ethoxylated (30) bisphenol A monomer; and
from about 5 to 18% by weight of epoxy acrylate.

24. The single-mode optical fiber of claim 1 , wherein said mode field diameter is 9.2 μm or greater at 1310 nm.

25. The single-mode optical fiber of claim 1 , wherein said single-mode optical fiber exhibits a bend loss at a wavelength of 1550 nm, when turned about a mandrel having a diameter of 20 mm, of less than 0.25 dB/turn.

26. The single-mode optical fiber of claim 1 , wherein said single-mode optical fiber exhibits a bend loss at a wavelength of 1550 nm, when turned about a mandrel having a diameter of 15 mm, of less than 0.25 dB/turn.

27. The single-mode optical fiber of claim 1 , wherein said mode field diameter is 9.2 μm or greater at 1310 nm.

28. The single-mode optical fiber of claim 1 , wherein said depressed index region of said cladding has a moat volume of at least 30% μm 2 .

Assignees

• Corning Inc

Inventors

• Bookbinder Dana Craig
• Dawes Steven Bruce
• Kouzmina Inna Igorevna
• Li Ming-Jun
• Ocampo Manuela
• Tandon Pushkar

Classifications

• G02B6/02009

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

• G02B6/02014 Primary

  Effective area greater than 60 square microns in the C band, i.e. 1530-1565 nm · CPC title

• C08F222/1067

  of alcohol terminated epoxy functional polymers, e.g. epoxy(meth)acrylates · CPC title

• C08F222/1025

  of aromatic dialcohols · CPC title

• G02B6/0365

  arranged - - + · CPC title