Reduced diameter multi mode optical fibers with high mechanical reliability

Patent metadata

Field	Value
Publication number	US-11579359-B2
Application number	US-202117316292-A
Country	US
Kind code	B2
Filing date	May 10, 2021
Priority date	May 12, 2020
Publication date	Feb 14, 2023
Grant date	Feb 14, 2023

Abstract

A disclosed multimode optical fiber comprises a core and a cladding surrounding the core. The core has an outer radius r 1 in between 20 μm and 30 μm. The cladding includes a first outer cladding region having an outer radius r 4a and a second outer cladding region having an outer radius r 4b less than or equal to 45 μm. The second outer cladding region comprises silica-based glass doped with titania. The optical fiber further includes a primary coating with an outer radius r 5 less than or equal to 80 μm, and a thickness (r 5 −r 4 ) less than or equal to 30 μm. The optical fiber further includes a secondary coating with an outer radius r 6 less than or equal to 100 μm. The secondary coating has a thickness (r 6 −r 5 ) less than or equal to 30 μm, and a normalized puncture load greater than 3.6×10 −3 g/micron 2 .

First claim

What is claimed is:

1. A multimode optical fiber, comprising:
a core region having an outer radius r 1 in a range from 20 microns to 30 microns;
a cladding region surrounding and directly adjacent to the core region, the cladding region including a first outer cladding region having an outer radius r 4a and a second outer cladding region surrounding and directly adjacent to the first outer cladding region and having an outer radius r 4b , wherein the second outer cladding region comprises silica-based glass doped with titania and r 4b is less than or equal to 45 microns;
a primary coating with an outer radius r 5 less than or equal to 80 microns surrounding and directly adjacent to the cladding region, the primary coating having a thickness (r 5 −r 4 ) less than or equal to 30 microns; and
a secondary coating with an outer radius r 6 less than or equal to 100 microns surrounding and directly adjacent to the primary coating, the secondary coating having a thickness (r 6 −r 5 ) less than or equal to 30 microns, and a normalized puncture load greater than 3.6×10 −3 g/micron 2 .

2. The multimode optical fiber of claim 1 , wherein:
the second outer cladding region has a titania concentration in a range from 4 wt % to 20 wt.

3. The multimode optical fiber of claim 1 , wherein:
the core region has a graded index relative refractive index profile with a maximum relative refractive index Δ 1max in a range from 0.8% to 1.20%.

4. The multimode optical fiber of claim 3 , wherein the graded index relative refractive index profile is an α-profile with a value of α in a range from 1.8 to 2.3.

5. The multimode optical fiber of claim 3 , wherein:
the first outer cladding region has an outer radius r 4a less than or equal to 43 microns; and
the second outer cladding region has a thickness (r 4b −r 4a ) in a range from 2 microns to 6 microns.

6. The multimode optical fiber of claim 1 , wherein:
the first outer cladding region has a relative refractive index Δ 4a that is in the range from −0.05% to 0.05%; and
the second outer cladding region has a relative refractive index Δ 4b that is larger than Δ 1max .

7. The multimode optical fiber of claim 1 , wherein:
the cladding region further includes an inner cladding region surrounding and directly adjacent to the core region, the inner cladding region having an outer radius r 2 and a thickness (r 2 −r 1 ) in a range from 1 micron to 15 microns; and
a relative refractive index Δ 2 of the inner cladding region is less than a relative refractive index Δ 4a of the first outer cladding region.

8. The multimode optical fiber of claim 1 , wherein:
the cladding region further includes an inner cladding region surrounding and directly adjacent to the core region, the inner cladding region having an outer radius r 2 and a thickness (r 2 −r 1 ) in a range from 1 micron to 15 microns; and
a relative refractive index Δ 2 of the inner cladding region is less than a relative refractive index Δ 4b of the second outer cladding region.

9. The multimode optical fiber of claim 1 , wherein:
the cladding region further includes an inner cladding region and a depressed index cladding region;
the inner cladding region directly surrounds the core region, and has an outer radius r 2 and a thickness (r 2 −r 1 ) in a range from 1 micron to 5 microns;
the depressed index cladding region directly surrounds the inner cladding region, and has an outer radius r 3 and a thickness (r 3 −r 2 ) in a range from 3 microns to 10 microns; and
a relative refractive index Δ 2 of the inner cladding region is greater than a relative refractive index Δ 3 of the depressed index cladding region.

10. The multimode optical fiber of claim 9 , wherein:
the relative refractive index Δ 2 is in the range from −0.05% to 0.05%; and
the relative refractive index Δ 3 is in a range from −0.55% to −0.1%.

11. The multimode optical fiber of claim 9 , wherein:
the depressed index cladding region has a trench volume in a range from 70% %Δ-micron 2 to 150%Δ-micron 2 .

12. The multimode optical fiber of claim 1 , wherein
the in situ modulus of the primary coating E p is less than or equal to 0.30 MPa; and
the Young's modulus of the secondary coating E s is greater than or equal to 1600 MPa.

13. The multimode optical fiber of claim 1 , wherein:
a diameter 2r 5 of the primary coating is less than or equal to 150 microns; and
a diameter 2r 6 of the secondary coating is less than or equal to 180 microns.

14. The multimode optical fiber of claim 1 , wherein the thickness (r 5 −r 4 ) of the primary coating is in a range from 8.0 microns to 20.0 microns.

15. The multimode optical fiber of claim 1 , wherein the thickness (r 6 −r 5 ) of the secondary coating is in a range from 8.0 microns to 20.0 microns.

16. The multimode optical fiber of claim 1 , wherein a ratio of the thickness (r 5 −r 4 ) of the primary coating to the thickness (r 6 −r 5 ) of the secondary coating is in a range from 0.5 to 1.5.

17. The multimode optical fiber of claim 1 , wherein a spring constant χ P of the primary coating is in a range from 0.3 MPa to 1.2 MPa.

18. The multimode optical fiber of claim 1 , further comprising:
a tertiary coating with an outer radius r 7 less than or equal to 100 microns surrounding and directly adjacent to the secondary coating, the tertiary coating having a thickness (r 7 −r 6 ) less than or equal to 10 microns.

19. The multimode optical fiber of claim 1 , wherein the primary coating is a cured product of a coating composition comprising:
a radiation-curable monomer;
an adhesion promoter, the adhesion promoter comprising an alkoxysilane compound or a mercapto-functional silane compound; and
an oligomer, the oligomer comprising:
a polyether urethane acrylate compound having the molecular formula:

wherein
R 1 , R 2 and R 3 are independently selected from linear alkylene groups, branched alkylene groups, or cyclic alkylene groups;
y is 1, 2, 3, or 4; and
x is between 40 and 100; and
a di-adduct compound having the molecular formula:

wherein the di-adduct compound is present in an amount of at least 1.0 wt % in the oligomer.

20. The multimode optical fiber of claim 19 , wherein the oligomer is the cured product of a reaction between:
a diisocyanate compound;
a hydroxy (meth)acrylate compound; and
a polyol compound, said polyol compound having unsaturation less than 0.1 meq/g;
wherein said diisocyanate compound, said hydroxy (meth)acrylate compound and said polyol compound are reacted in molar ratios n:m:p, respectively, wherein n is in the range from 3.0 to 5.0, m is within ±15% of 2n−4, and p is 2.

21. The multimode optical fiber of claim 1 , wherein the secondary coating is the cured product of a composition comprising:
an alkoxylated bisphenol-A diacrylate monomer in an amount greater than 55 wt %, the alkoxylated bisphenol-A diacrylate monomer having a degree of alkoxylation in the range from 2 to 16; and
a triacrylate monomer in an amount in the range from 2.0 wt % to 25 wt %, the triacrylate monomer comprising an alkoxylated trimethylolpropane triacrylate monomer having a degree of alkoxylation in the range from 2 to 16 or a tris[(acryloyloxy)alkyl] isocyanurate monomer.

22. The multimode optic

Assignees

• Corning Inc

Inventors

• Bennett Kevin Wallace
• Bickham Scott Robertson
• Tandon Pushkar
• Tandon Ruchi Sarda
• Yang Bin

Classifications

• G02B2006/12073

  Epoxy · CPC title

• G02B6/0288 Primary

  Multimode fibre, e.g. graded index core for compensating modal dispersion · CPC title

• G02B6/12002 Primary

  Three-dimensional structures · CPC title

• G02B6/03683

  arranged - - + + · CPC title

• C03B37/027

  Fibres composed of different sorts of glass, {e.g. glass optical fibres}(C03B37/0253, C03B37/028 take precedence) · CPC title