BENDING-RESISTANT LARGE CORE DIAMETER HIGH NUMERICAL APERTURE MULTIMODE FIBER

• US 20130279868A1
• Filed: 03/13/2012
• Published: 10/24/2013
• Est. Priority Date: 06/28/2011
• Status: Active Grant

• Current Assignee: EverPro Technologies Company Ltd.
• Original Assignee: Yangtze Opital Fibre and Cable Company Limited
• Inventors: Zhang, Shuqiang, He, Zhenbao, Liu, Yongtao, Wang, Song, Xu, Jin
• Granted Patent: US 9,052,435 B2
• Time in Patent Office: Days
• US Class Current: 385/127
• CPC Class Codes: G02B 6/02 Optical fibres with cladding with or without a coating
• CPC Class Codes: G02B 6/0288 Multimode fibre, e.g. graded index core for compensating modal dispersion
• CPC Class Codes: G02B 6/03627 arranged - +
• CPC Class Codes: G02B 6/0365 arranged - - +

Abstract

A bending-resistant large core diameter high numerical aperture multimode fiber includes a core and a cladding surrounding the core. The core has a radius R1 in a range of 28 to 50 microns, a refractive index profile of a parabola shape with α being in a range of 1.9 to 2.2, and a maximum relative refractive index difference Δ1% max being in a range of 1.9% to 2.5%. The cladding includes an inner cladding and/or a trench cladding, and an outer cladding disposed from the inner to the outer in sequence. The radius R2 of the inner cladding is in a range of 28 to 55 microns, and the relative refractive index difference Δ2% is −0.1% to 0.1%. The radius R3 of the trench cladding is in a range of 28 to 60 microns, and the relative refractive index difference Δ3% is in a range of −0.15% to −0.8%.

Claims

1. A bending-resistant multimode fiber with a large core diameter and a high numerical aperture, comprising:

a core; and

a cladding surrounding the core;

wherein a radius R1 of the core is in a range of 28 to 50 microns, a refractive index profile of the core has a parabolic shape, α

is in a range of 1.9 to 2.2, and a maximum relative refractive index difference Δ

1% max is in a range of 1.9% to 2.5%; and

wherein the cladding comprises an inner cladding and/or a trench cladding, and an outer cladding disposed from the inner to the outer in sequence;

wherein the inner cladding has a radius R2 in a range of 28 to 55 microns, and a relative refractive index difference Δ

2% in a range of −

0.1% to 0.1%, and wherein the trench cladding has a radius R3 in a range of 28 to 60 microns, and a relative refractive index difference Δ

3% in a range of −

0.15% to −

0.8%.

2. The bending-resistant multimode fiber according to claim 1, wherein the outer cladding surrounds the trench cladding, wherein a radius R4 of the outer cladding is in a range of 60 to 65 microns, and a relative refractive index difference Δ

4% of the outer cladding is in a range of −

0.1% to 0.1%.

3. The bending-resistant multimode fiber according to claim 1, wherein the relative refractive index difference Δ

3% of the trench cladding is radially constant or radially gradual changed, wherein the gradual change of the relative refractive index difference Δ

3% comprises a gradual change in an ascending order from inside to outside or a gradual change in a descending order from inside to outside.

4. The bending-resistant multimode fiber according to claim 1, wherein the core and the claddings are made of Ge-doped, F-doped, Ge—

F-doped or pure quartz glass.

5. The bending-resistant multimode fiber according to claim 1, having a bandwidth of 200 MHz-km or over 200 MHz-km at a wavelength of 850 nm.

6. The bending-resistant multimode fiber according to claim 5, having a numerical aperture in a range of 0.29 to 0.33.

7. The bending-resistant multimode fiber according to claim 1, having a bandwidth of 200 MHz-km or over 200 MHz-km at a wavelength of 1300 nm.

8. The bending-resistant multimode fiber according to claim 1, wherein for the fiber at the wavelength of 850 nm, a bending loss resulted by winding the fiber two turns at a bend radius of 7.5 millimeters is less than or equal to 0.35 dB;

the bending loss resulted by winding the fiber two turns at the bend radius of 15 millimeters is less than or equal to 0.2 dB; and

the bending loss resulted by winding the fiber 100 turns at the bend radius of 30 millimeters is less than or equal to 0.2 dB.

9. The bending-resistant multimode fiber according to claim 2, wherein the relative refractive index difference Δ

3% of the trench cladding is radially constant or radially gradual changed, wherein the gradual change of the relative refractive index difference Δ

3% comprises a gradual change in an ascending order from inside to outside or a gradual change in a descending order from inside to outside.

10. The bending-resistant multimode fiber according to claim 2, wherein the core and the claddings are made of Ge-doped, F-doped, Ge—

F-doped or pure quartz glass.

11. The bending-resistant multimode fiber according to claim 2, having a bandwidth of 200 MHz-km or over 200 MHz-km at a wavelength of 850 nm.

12. The bending-resistant multimode fiber according to claim 11, having a numerical aperture in a range of 0.29 to 0.33.

13. The bending-resistant multimode fiber according to claim 2, having a bandwidth of 200 MHz-km or over 200 MHz-km at a wavelength of 1300 nm.

14. The bending-resistant multimode fiber according to claim 2, wherein for the fiber at the wavelength of 850 nm, a bending loss resulted by winding the fiber two turns at a bend radius of 7.5 millimeters is less than or equal to 0.35 dB;

the bending loss resulted by winding the fiber two turns at the bend radius of 15 millimeters is less than or equal to 0.2 dB; and

the bending loss resulted by winding the fiber 100 turns at the bend radius of 30 millimeters is less than or equal to 0.2 dB.