Few-mode optical fiber

Patent metadata

Field	Value
Publication number	US-10451797-B2
Application number	US-201716321844-A
Country	US
Kind code	B2
Filing date	Dec 18, 2017
Priority date	Oct 18, 2016
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

Provided is a few-mode optical fiber. The optical fiber includes: a core and a cladding enclosing the core. The cladding includes: a first inner cladding surrounding the core; a first high-refractive-index mode filter layer surrounding the first inner cladding; a second inner cladding surrounding the first high-refractive-index mode filter layer; a second high-refractive-index mode filter layer surrounding the second inner cladding; and an outer cladding surrounding the second high-refractive-index mode filter layer.

First claim

What is claimed is:

1. A few-mode optical fiber, comprising:
a core; and
a cladding surrounding the core,

wherein the cladding comprises:
a first inner cladding surrounding the core;
a first high-refractive-index mode filter layer surrounding the first inner cladding;
a second inner cladding surrounding the first high-refractive-index mode filter layer;
a second high-refractive-index mode filter layer surrounding the second inner cladding; and
an outer cladding surrounding the second high-refractive-index mode filter layer,

wherein the core has a refractive index of n1, the first inner cladding has a refractive index of n2, the first high-refractive-index mode filter layer has a refractive index of n3, the second inner cladding has a refractive index of n4, the second high-refractive-index mode filter layer has a refractive index of n5, the outer cladding has a refractive index of n6, satisfying: n1>n3>n5>n6 and n2=n4=n6; the core and the first inner cladding satisfy: 2.405<V<4.4, wherein

V
=

2
⁢

⁢
π
⁢

⁢

a
1

λ
0

⁢

(

n
1
2

-

n
2
2

)

1
/
2

,

V denotes a normalized frequency, λ 0 =1625 nm, and a1 denotes a radius of the core; the refractive index n3 and a radial thickness a3 of the first high-refractive-index mode filter layer satisfy: 1.7<F<3.3 and V>F, wherein

F
=

2
⁢
π
⁢

⁢

a
3

λ
0

⁢

(

n
3
2

-

n
6
2

)

1
/
2

;

and the first inner cladding has a radial thickness of a2, the first high-refractive-index mode filter layer has the radial thickness of a3, the second inner cladding has a radial thickness of a4, the second high-refractive-index mode filter layer has a radial thickness of a5.

2. The few-mode optical fiber of claim 1 , wherein an effective refractive index of an LP11 mode of the optical fiber is greater than an effective refractive index of a cladding defect mode of the optical fiber in a wavelength range of 1260 to 1625 nm.

3. The few-mode optical fiber of claim 1 , wherein the refractive index of the first high-refractive-index mode filter layer and the refractive index of the second high-refractive-index mode filter layer satisfy: n3−n5>(a5/2+a4+a3/2)/Rb, wherein Rb=7.5 mm.

4. The few-mode optical fiber of claim 1 , wherein the radial thickness a3 of the first high-refractive-index mode filter layer and the radial thickness a5 of the second high-refractive-index mode filter layer satisfy: a3≥a5.

5. The few-mode optical fiber of claim 1 , wherein the refractive index n1 of the core and the refractive index n6 of the outer cladding satisfy: 0.015>n1−n6>0.007.

6. The few-mode optical fiber of claim 1 , wherein the radial thickness a2 of the first inner cladding satisfies: 7.9 μm≥a2≥4.0 μm.

7. The few-mode optical fiber of claim 1 , wherein the radial thickness a3 of the first high-refractive-index mode filter layer satisfies: 8.5 μm≥a3≥3.5 μm.

8. The few-mode optical fiber of claim 1 , wherein the radial thickness a4 of the second inner cladding satisfies: 4.6 μm≥a4≥2.4 μm.

9. The few-mode optical fiber of claim 1 , wherein the radial thickness a5 of the second high-refractive-index mode filter layer satisfies: 8.5 μm≥a5≥3.5 μm.

10. The few-mode optical fiber of claim 1 , wherein at a wavelength of 1550 nm, the optical fiber has a bending loss satisfying:
when a bending radius Rb≥7.5 mm, a bending loss in an LP01 mode is less than 1×10 −3 dB/turn; and
when the bending radius Rb≤7.5 mm, a bending loss in an LP11 mode is greater than 5 dB/turn.

Assignees

• State Grid Jiangxi Electric Power Company Information & Telecommunication Branch
• State Grid Corp China
• Univ Jiangsu
• Jangsu Univ

Inventors

• Wang Hua
• Chen Mingyang
• Wu Xiaosheng
• Li Renhua
• Cai Zhimin
• Cao Guodong
• Li Shenyi
• Li Luming
• Yang Jihai
• Fu Pingping
• Zheng Meilan
• Xiao Hui
• Chu Hongliang
• Li Jun
• Yin Fang

Classifications

• G02B6/03694

  Multiple layers differing in properties other than the refractive index, e.g. attenuation, diffusion, stress properties · CPC title

• G02B6/03688 Primary

  having 5 or more layers · CPC title

• G02B6/02019

  Effective area greater than 90 square microns in the C band, i.e. 1530-1565 nm · CPC title

• G02B6/03644

  arranged - + - · CPC title

• G02B6/02261

  Dispersion compensating fibres, i.e. for compensating positive dispersion of other fibres · CPC title