US 12,736,742 B2 · Multi-core optical fiber

Abstract

The multi-core optical fiber includes a plurality of cores, a first cladding, and a second cladding. The second cladding has a refractive index lower than a refractive index of each of the cores and higher than a refractive index of the first cladding. The multi-core optical fiber has a transmission loss of 0.22 dB/km or less. When an effective area of each of the cores is denoted as Aeff, a center-to-center distance between two cores is denoted as Λ, and a relative refractive index difference of each of the cores with respect to the refractive index of the first cladding is denoted as Δcore, Aeff1 is defined by Aeff ⁢ 1 = 18.6 - 4.63 ln ⁢ ( Δcore ) + 1.24 Λ + 2 ⁢ 4 . 1 [ ln ⁢ ( Δcore ) ] ⁢ 2 - 6.05 × 10 - 3 ⁢ Λ2 - 0.858 Λ ⁢ ln ⁢ ( Δcore ) , and the multi-core optical fiber satisfies Condition below by using Aeff1. 0.35 ≤ Δcore ≤ 1. 25 ≤ Λ ≤ 5 ⁢ 0 0.8 Aeff ⁢ 1 ≤ Aeff ≤ 1.35 Aeff ⁢ 1

Claims22

Dependent claims

A common depressed cladding type multi-core optical fiber configured to be used for co-propagation, the multi-core optical fiber comprising:

a plurality of cores;
a common first cladding configured to surround each of the plurality of cores;
and
a second cladding configured to surround the first cladding,
wherein the second cladding has a refractive index lower than a refractive index of each of the cores and higher than a refractive index of the first cladding,
wherein the multi-core optical fiber has a transmission loss of 0.22 dB/km or less at a wavelength of 1550 nm, and
wherein, when an effective area of each of the cores at a wavelength of 1550 nm is denoted as Aeff [μm2], a center-to-center distance between two of the cores, the two cores being adjacent to each other, in a cross section perpendicular to a fiber axis is denoted as Λ [μm], and a relative refractive index difference of each of the cores with respect to the refractive index of the first cladding is denoted as Δcore [%], Aeff1 [μm2] is defined by
Aeff
⁢
1
=
18.6
-
4.63
ln
⁡
(
Δ
⁢
core
)
+
1.24
Λ
+
2
⁢
4
.
1
[
ln
⁡
(
Δ
⁢
core
)
]
2
-
6.05
×
1
⁢
0
-
3
⁢
Λ
2
-
0.858
Λ
⁢
ln
⁡
(
Δ
⁢
core
)
,
and
the multi-core optical fiber satisfies the following condition which is Condition 1a by using Aeff1 [μm2]:
0.35
[
%
]
≤
Δ
⁢
core
[
%
]
≤
1.
[
%
]
⁢
25
[
µm
]
≤
Λ
[
µm
]
≤
50
[
µm
]
⁢
0.8
Aeff
⁢
1
≤
Aeff
≤
1.35
Aeff
1.

104 more elements

Dependencies are inferred from the claim text.

Multi-core optical fiber

Life of this patent

Multi-core optical fiber

Life of this patent

Abstract

Claims22