Optical fiber with large mode field diameter and low microbending losses

Patent metadata

Field	Value
Publication number	US-10094973-B2
Application number	US-201615193860-A
Country	US
Kind code	B2
Filing date	Jun 27, 2016
Priority date	May 2, 2013
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

Optical fibers having a mode field diameter at 1310 nm of at least 8.8 μm, wire mesh covered drum microbending losses at 1550 nm less than 0.03 dB/km, and a 2 m cutoff wavelength less than 1320 nm. The fibers may include a central core region, an inner cladding region, an outer cladding region, a primary coating with an in situ modulus less than 0.20 MPa and glass transition temperature less than −35° C., and a secondary coating with an in situ modulus greater than 1500 MPa. The fibers may further include a depressed index cladding region. The relative refractive index of the central core region may be greater than the relative refractive index of the outer cladding region may be greater than the relative refractive index of the inner cladding region. The fibers may be produced at draw speeds of 30 m/s or greater.

First claim

What is claimed is:

1. An optical waveguide fiber comprising:
a central core region having a radius r 1 and a relative refractive index Δ 1 (r) in % measured relative to pure silica, said relative refractive index Δ 1 (r) having a maximum Δ 1max ;
a cladding, said cladding including an inner cladding region surrounding said central core region and an outer cladding region surrounding said inner cladding region, said inner cladding region having an outer radius r 2 >8 μm and a relative refractive index Δ 2 (r) in % measured relative to pure silica, said relative refractive index Δ 2 (r) having a maximum Δ 2max and a minimum Δ 2min , said outer cladding region having a relative refractive index Δ 4 in % measured relative to pure silica, said relative refractive index Δ 4 being positive and less than said maximum Δ 1max , said relative refractive index Δ 4 exceeding said minimum Δ 2min by at least 0.002%;
a primary coating surrounding said outer cladding region, said primary coating having an in situ modulus of less than 0.20 MPa and an in situ glass transition temperature of less than −35° C.; and
a secondary coating surrounding said primary coating, said secondary coating having an in situ modulus of greater than 1500 MPa
wherein said fiber exhibits a wire mesh covered drum microbending loss less than 0.030 dB/km at a wavelength of 1550 nm when wound around a mesh-covered aluminum drum with a diameter of 400 mm.

2. The fiber of claim 1 , wherein said relative refractive index percent profile Δ 1 (r) is a super-Gaussian profile, said super-Gaussian profile being substantially described by the equation

Δ
1

⁡

(
r
)

=

Δ

1
⁢

⁢
m
⁢

⁢
a
⁢

⁢
x

⁢

EXP
⁡

[

-

(

r
a

)

γ

]

where γ>0 and a>4.5.

3. The fiber of claim 1 , wherein said relative refractive index percent profile Δ 1 (r) is an α-profile, said α-profile being substantially described by the equation

Δ
1

⁡

(
r
)

=

Δ

1
⁢
max

⁡

[

1
-

[



r
-

r
m



(

r
2

-
m

)

]

α

]

where r m is the radius at which Δ(r)=Δ max , r z is the radius at which Δ(r)=0, and α is between 0.5 and 10.

4. The fiber of claim 1 , wherein said relative refractive index Δ 4 is at least 0.010%.

5. The fiber of claim 1 , wherein the width of said inner cladding region is between 3 μm and 13 μm.

6. The fiber of claim 1 , wherein said relative refractive index Δ 4 exceeds said minimum Δ 2min by at least 0.02%.

7. The fiber of claim 1 , wherein said cladding further comprises a depressed index cladding region between said inner cladding region and said outer cladding region, said depressed index cladding region having a relative refractive index Δ 3 (r) with a minimum Δ 3min , said minimum Δ 3min being less than said minimum Δ 2min by at least 0.005%, said minimum Δ 3min being less than said relative refractive index Δ 4 by at least 0.010%.

8. The fiber of claim 1 , wherein said fiber exhibits a mode field diameter greater than 8.8 μm at a wavelength of 1310 nm.

9. The fiber of claim 1 , wherein said fiber exhibits a 2 m cutoff wavelength less than 1360 nm.

10. The fiber of claim 1 , wherein said primary coating has an in situ glass transition temperature of less than −45° C.

11. The fiber of claim 1 , wherein the outer diameter of said primary coating is less than 185 μm.

12. 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.

13. The fiber of claim 12 , 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.

14. The fiber of claim 12 , 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.

15. The fiber of claim 1 , wherein said secondary coating has an in situ modulus of 1800 MPa or greater.

16. The fiber of claim 1 , wherein

Assignees

• Corning Inc

Inventors

• Bickham Scott Robertson
• Lewis Kevin Alton
• Mishra Snigdharaj Kumar
• Ocampo Manuela
• Patterson Joan Diana

Classifications

• 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

• C03C25/1065

  Multiple coatings · CPC title

• C03C25/326

  Polyureas; Polyurethanes · CPC title

• G02B6/02009 Primary

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