Optical fiber

Patent metadata

Field	Value
Publication number	US-11808972-B2
Application number	US-202217743884-A
Country	US
Kind code	B2
Filing date	May 13, 2022
Priority date	Nov 8, 2019
Publication date	Nov 7, 2023
Grant date	Nov 7, 2023

Abstract

An optical fiber includes a glass portion, a primary coating layer, and a secondary coating layer. In the optical fiber, a value of microbend loss characteristic factor F μBL_GΔβ is 6.1 ([GPa −1 ·μm −2.5 /rad 8 ]·10 −12 ) or less when represented by

F μBL_GΔβ =F μBL_G ×F μBL_Δβ ,

where F μBL_G is geometry microbend loss characteristic and F μBL_Δβ is optical microbend loss characteristic.

First claim

What is claimed is:

1. An optical fiber comprising:
a glass portion including a core;
a clad surrounding the core;
a primary coating layer covering the clad; and
a secondary coating layer covering the primary coating layer, wherein
a value of microbend loss characteristic factor F μBL_GΔβ ([GPa −1 ·μm −2.5 /rad 8 ]·10 −12 ) is 6.1 ([GPa −1 ·μm −2.5 /rad 8 ]·10 −12 ) or less when represented by
F μBL_GΔβ =F μBL_G ×F μBL_Δβ ,

wherein geometry microbend loss characteristic F μBL_G (GPa −1 ·μm −10.5 ·10 −27 ) of the optical fiber is represented by

F

μ
⁢
BL_G

=

K
s
2

H
f
2

×

D
0
0.375

×

H
0
0.625

K
s

=

E
p

⁢

d
f

t
p

,

H
f

=

π
4

⁢

E
g

(

d
f

2

)

4

,

D
0

=

E
p

+

(

t
s

R
s

)

3

⁢

E
s

,

H
0

=

π
4

⁢

E
s

(

R
s
4

-

R
p
4

)

,

where
κs (MPa) is a spring coefficient of the primary coating layer,
H f (MPa·μm 4 ) is a bending rigidity of the glass portion,
D 0 (MPa) is a deformation resistance of the secondary coating layer,
H 0 (MPa·μm 4 ) is a bending rigidity of the secondary coating layer,
E g (GPa) is a Young's modulus of the glass portion,
E p (MPa) is a Young's modulus of the primary coating layer,
E s (MPa) is a Young's modulus of the secondary coating layer,
d f (μm) is an outside diameter of the glass portion,
R p (μm) is a radius of an outer peripheral surface of the primary coating layer,
R s (μm) is a radius of an outer peripheral surface of the secondary coating layer,
t p (μm) is a thickness of the primary coating layer, and
t s (μm) is a thickness of the secondary coating layer, and
wherein optical microbend loss characteristic F μBL_Δβ (1/(rad/μm) 8 ) of the optical fiber is represented by

F

μ
⁢
BL_β

=

1

(

Δ
⁢
β

)

8

,

where Δβ (rad/m) is a propagation constant difference between propagation constant of a waveguide mode propagating through the optical fiber and propagation constant of a radiation mode, and

the value of microbend loss characteristic factor is 6.1 ([GPa −1 ·μm −2.5 /rad 8 ]·10 −12 ) or less (excluding 5.83 ([GPa −1 ·μm −2.5 /rad 8 ]·10 −12 ) and 5.99 ([GPa −1 ·μm −2.5 /rad 8 ]·10 −12 )).

2. The optical fiber according to claim 1 , wherein the value of the microbend loss characteristic factor is 5.8 ([GPa −1 ·μm −2.5 /rad 8 ]·10 −12 ) or less.

3. The optical fiber according to claim 1 , wherein the value of the microbend loss characteristic factor is 3.75 ([GPa −1 ·μm −2.5 /rad 8 ]·10 −12 ) or less.

4. The optical fiber according to claim 1 , wherein a coating thickness of a sum of the thickness of the primary coating layer and the thickness of the secondary coating layer is 42.0 μm or less.

5. The optical fiber according to claim 4 , wherein the outside diameter of the glass portion is 65 μm or more and 100 μm or less.

6. The optical fiber according to claim 1 , wherein the outside diameter of the glass portion is 65 μm or more and 100 μm or less.

7. The optical fiber according to claim 1 , wherein the Young's modulus of the primary coating layer is 0.08 MPa or more and 0.70 MPa or less.

8. The optical fiber according to claim 7 , wherein the Young's modulus of the secondary coating layer

Assignees

• Fujikura Ltd

Inventors

• Maruyama Ryo
• Yamashiro Kenji

Classifications

• G02B6/02395 Primary

  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

• G02B6/02214

  tailored to obtain the desired dispersion, e.g. dispersion shifted, dispersion flattened · CPC title

• G02B6/4411 Primary

  Matrix structure · CPC title

• G02B6/4434

  Central member to take up tensile loads · CPC title

• G02B6/4479

  Manufacturing methods of optical cables · CPC title