Optical fiber cable
An optical fiber cable includes: optical fibers each including a glass portion including a core and a cladding surrounding the core, a primary covering layer covering the cladding, and a secondary covering layer covering the primary covering layer; and a sheath accommodating the optical fibers in an internal space. A value of a micro-bend loss characteristic factor F μBL_GO is 5.2×10 23 or less when represented by F μBL_GO =F μBL_G ×F μBL_O ×Dc.
1 . An optical fiber cable comprising:
ribbons in which optical fibers are intermittently bonded with resin along a longitudinal direction; and
a sheath accommodating the ribbons in an internal space,
wherein each of the optical fibers comprises:
a glass portion including a core and a cladding surrounding the core;
a primary covering layer that covers the cladding of the glass portion; and
a secondary covering layer that covers the primary covering layer,
wherein a value of a micro-bend loss characteristic factor F μBL_GO is 5.2×10 23 or less when represented by
F μBL_GO =F μBL_G ×F μBL_O ×Dc,
where F μBL_G (Pa −1 ·m −10.5 ) is a geometry micro-bend loss characteristic of each optical fiber represented by
F
μ
BL_G
=
K
s
2
H
f
2
×
D
o
0.375
×
H
o
0.625
,
K
s
=
E
p
d
f
t
p
,
H
f
=
π
4
E
g
(
d
f
2
)
4
,
D
o
=
E
p
+
(
t
s
R
s
×
2
)
3
E
s
,
H
o
=
π
4
E
s
(
R
s
4
-
R
p
4
)
,
where
H f (Pa·m 4 ) is a flexural rigidity of the glass portion,
D 0 (Pa)a is deformation resistance of the secondary covering layer,
H 0 (Pa·m 4 )a is flexural rigidity of the secondary covering layer,
E g (GPa)a is Young's modulus of the glass portion,
E p (MPa) is a Young's modulus of the primary covering layer,
E s (MPa) is a Young's modulus of the secondary covering layer,
d f (μm) is an outer diameter of the glass portion,
R p (μm) is a radius of an outer circumferential surface of the primary covering layer,
R s (μm) is a radius of an outer circumferential surface of the secondary covering layer,
t p (μm) is a thickness of the primary covering layer, and
t s (μm) is a thickness of the secondary covering layer,
F μBL_O (dB/turn) is an optical micro-bend loss characteristic of each optical fiber represented by
F
μ
BL_O
=
2
w
λ
cc
×
α
BL
,
where
2w (μm) is a mode field diameter of light having a wavelength of 1310 nm propagating through each optical fiber,
λ cc (μm) is a cable cutoff wavelength of each optical fiber, and
α BL (dB/turn) is a macro-bend loss with a radius of 10 mm of light having a wavelength of 1625 nm of each optical fiber, and
Dc is a cable characteristic of the optical fiber cable represented by
Dc =(0.5− a ) 2 /b,
where a is a porosity of the internal space and b is a number of cores of the optical fibers accommodated in the internal space,
wherein
the outer diameter d f of the glass portion is 80 (μm) or more and 90 (μm) or less, and
the porosity of the internal space is 0.31 or more and 0.42 or less.
2 . The optical fiber cable according to claim 1 ,
wherein the value of the micro-bend loss characteristic factor F μBL_GO is 4.0× 10 23 or less.
3 . The optical fiber cable according to claim 2 ,
wherein the value of the micro-bend loss characteristic factor F μBL_GO is 3.2×10 23 or less.
4 . The optical fiber cable according to claim 1 ,
wherein a propagation constant difference corresponding to a difference between a propagation constant in LP01 mode of light having a wavelength of 1550 nm propagating through the optical fiber and a propagation constant in LP11 mode is 1.10×10 4 (rad/m) or more and 1.53×10 4 (rad/m) or less.
5 . The optical fiber cable according to claim 1 ,
wherein a value Ks corresponding to a value obtained by multiplying a Young's modulus E p (MPa) of the primary covering layer and an outer diameter d f (μm) of the glass portion, and dividing it by a thickness t p (μm) of the primary covering layer is 6.0×10 5 (Pa) or more and 1.2×10 6 (Pa) or less.
6 . The optical fiber cable according to claim 1 ,
wherein a flexural rigidity H f of the glass portion is 1.49×10 −7 (Pa·m 4 ) or more and 2.38×10 −7 (Pa·m 4 ) or less.
7 . The optical fiber cable according to claim 1 ,
wherein the deformation resistance D 0 of the secondary covering layer is 1.8×10 6 (Pa) or more and 3.6×10 6 (Pa) or less.
8 . The optical fiber cable according to claim 1 ,
wherein a flexural rigidity H 0 of the secondary covering layer is 2.09×10 −8 (Pa·m 4 ) or more and 3.22×10 −8 (Pa·m 4 ) or less.
9 . The optical fiber cable according to claim 1 ,
wherein a Young's modulus E p (MPa) of the primary covering layer is 0.13 (MPa) or more and 0.22 (MPa) or less.
10 . The optical fiber cable according to claim 1 ,
wherein a radius R p of the outer circumferential surface of the primary covering layer is 54.8 (μm) or more and 61.0 (μm) or less.
11 . The optical fiber cable according to claim 1 ,
wherein a radius R s of the outer circumferential surface of the secondary covering layer is 75.4 (μm) or more and 80.5 (μm) or less.
12 . The optical fiber cable according to claim 1 ,
wherein a sum of the thickness of the primary covering layer and the thickness of the secondary covering layer is 60 μm or less.
13 . The optical fiber cable according to claim 12 ,
wherein the sum of the thickness of the primary covering layer and the thickness of the secondary covering layer is 37.5 μm or less.
14 . The optical fiber cable according to claim 1 ,
wherein an outer diameter of the secondary covering layer is less than 160 μm.