US 2026/0227565 A1 · MULTICORE OPTICAL FIBER AND MULTICORE OPTICAL FIBER CABLE

Abstract

An MCF comprises 12 or 16 core units each including a core and a depressed layer, a common cladding, and a resin coating. On the cross section, the core units are disposed such that an adjacency relationship is not established between cores each establishing an adjacency relationship with a specific core, and are disposed such that the centers of the core units are line-symmetric with respect to a symmetry axis that is an axis crossing a central axis and not passing the center of any of the core units. The outer diameter of the resin coating, an effective cross-sectional area, and the cut-off wavelength satisfy a specific range. The center-to-center distance of adjacent cores, the shortest distance from a core center to an interface between the common cladding and the resin coating, and the smallest outer diameter of the common cladding satisfy a specific relationship.

A multi-core optical fiber comprising:

12 or 16 core units each including a core extending along a central axis and a depressed layer covering an outer periphery of the core, the depressed layer having a refractive index lower than a maximum refractive index of the core;
a common cladding having a refractive index higher than the refractive index of the depressed layer and covering an outer periphery of each of the 12 or 16 core units;
and
a resin coating covering an outer periphery of the common cladding,
wherein, on a cross section of the multi-core optical fiber orthogonal to the central axis, the 12 or 16 core units are arranged such that no adjacent relationship is established between cores each having an adjacent relationship with one specific core selected from the 12 or 16 core units, and are each arranged such that centers of the 12 or 16 core units are line symmetric with respect to an axis as a symmetry axis that intersects with the central axis and that passes through none of the centers of the 12 or 16 core units,
the resin coating has an outer diameter of 250±15 μm,
an effective cross-sectional area Aeff_1550 [μm2] at a wavelength of 1.550 μm is 70 μm2 or more,
a cable cutoff wavelength λcc [μm] at a length of 22 m is 1.530 μm or less, or 1.460 μm or less,
when a radius of the core is denoted as ra [μm], an inner radius of the depressed layer is denoted as rb [μm], an outer radius of the depressed layer is denoted as rc [μm], and an absolute value of a relative refractive index difference of the depressed layer with a refractive index of the common cladding used as a reference is denoted as Δdep [%], a center-to-center distance Λ [μm] between the cores each having the adjacent relationship satisfies a following Formula (1),
a shortest distance d_coat [μm] from a center of the core to an interface between the common cladding and the resin coating satisfies a following Formula (2),
in a configuration in which the common cladding surrounds an outer periphery of each of the 12 core units, a minimum outer diameter CD [μm] of the common cladding is 185 μm or less, 190 μm or less, or 195 μm or less, and further satisfies a following Formula (3), and
in a configuration in which the common cladding surrounds an outer periphery of each of the 16 core units, the minimum outer diameter CD [μm] of the common cladding is 195 μm or less, and further satisfies a following Formula (4).
[
Math
.
1
]

Λ
≥
6.51
Aeff_
⁢
1550
/
π
λ
⁢
cc
+
14.2
1
+
0.528
Δ
⁢
dep
⁢
(
rc
-
rb
ra
)
(
1
)
[
Math
.
2
]

d_coat
≥
7.35
Aeff_
⁢
1550
/
π
λ
⁢
cc
+
4.6
1
+
0.5
Δ
⁢
dep
⁢
ln
⁢
rc
ra
(
2
)
[
Math
.
3
]

CD
≥
2
[
1.5
2
+
0.5
2
⁢
6.51
Aeff
/
π
λ
⁢
cc
+
14.2
1
+
0.528
Δ
⁢
dep
⁢
(
rc
-
rb
ra
)
+

⁢
7.35
Aeff_
⁢
1550
/
π
λ
⁢
cc
+
4.6
1
+
0.5
Δ
⁢
dep
⁢
ln
⁢
rc
ra
(
3
)
[
Math
.
4
]

CD
≥
2
[
1.5
2
⁢
6.51
Aeff
/
π
λ
⁢
cc
+
14.2
1
+
0.528
Δ
dep
⁢
(
rc
-
rb
ra
)
+
7.35
Aeff_
⁢
1550
/
π
λ
⁢
cc
+
4.6
1
+
0.5
Δ
⁢
dep
⁢
ln
⁢
rc
ra
]
(
4
)

204 more elements

Multicore optical fiber and multicore optical fiber cable

Life of this patent

Multicore optical fiber and multicore optical fiber cable

Life of this patent

Abstract

Claims8