Bend-insensitive single mode optical fiber

• US 10,641,952 B2
• Filed: 05/10/2018
• Issued: 05/05/2020
• Est. Priority Date: 05/16/2017
• Status: Active Grant

• Current Assignee: Yangtze Optical Fibre and Cable Joint Stock Limited Company (Prysmian SPA)
• Original Assignee: Yangtze Optical Fibre and Cable Joint Stock Limited Company (Prysmian SPA)
• Inventors: Yu, Jiangang, Yang, Chen, Wang, Song
• Primary Examiner(s): Mooney, Michael P
• Application Number:
  US15/975,913
• Publication Number:
  US 20180335562A1
• Time in Patent Office: 726 Days
• Field of Search: 385 43, 385123-128
• CPC Class Codes: G02B 6/028 with core or cladding having graded refractive index G02B6/02033, G02B6/02295 take precedence
• CPC Class Codes: G02B 6/03638 having 3 layers only
• CPC Class Codes: G02B 6/03655 arranged - + +
• CPC Class Codes: G02B 6/2552 reshaping or reforming of light guides for coupling using thermal heating, e.g. tapering, forming of a lens on light guide ends
• CPC Class Codes: G02B 6/305 and having an integrated mode-size expanding section, e.g. tapered waveguide

Abstract

A fused-biconical-taper bend-insensitive single mode optical fiber includes a core and a cladding. The core is a fluorine-germanium co-doped silicon-dioxide quartz glass layer, a diameter D_core thereof is 7-10 μm, and a relative refractive index difference Δ1 thereof is 0.20% to 0.40%. A range of ΔGe is 0.30% to 0.60%, and a range of ΔF is −0.05% to −0.15%. The cladding includes three layers. A first layer is a fluorine-germanium co-doped silicon-dioxide quartz glass layer, a relative refractive index difference Δ31 thereof is −0.02% to −0.10%, and a diameter D31 thereof is 15-30 μm. A second layer is a fluorine-doped silicon-dioxide quartz glass layer, a relative refractive index difference Δ32 thereof is −0.01% to −0.05%, and a diameter D32 thereof is 30-50 μm. A third layer is a pure silicon-dioxide quartz glass layer, and a diameter D33 thereof is 124-126 μm.

Claims

1. A bend-insensitive single mode optical fiber suitable for use in a fused biconical taper, comprising a core and a cladding, wherein:

the core is a fluorine-germanium co-doped silicon-dioxide quartz glass layer, a diameter D_core thereof is 7 μ

m to 10 μ

m, and a relative refractive index difference Δ

1 thereof is 0.20% to 0.40%, wherein a range of Δ

Ge is 0.30% to 0.60%, and a range of Δ

F is −

0.05% to −

0.15%; and

the cladding comprises three layers, wherein;

a first layer closely surrounds the core, the first layer is a fluorine-germanium co-doped silicon-dioxide quartz glass layer, a diameter D31 thereof is 15 μ

m to 30 μ

m, and a relative refractive index difference Δ

31 thereof is −

0.02% to −

0.10%, wherein a range of Δ

Ge is 0.05% to 0.25%, and a range of Δ

F is −

0.05% to −

0.30%;

a second layer closely surrounds the first layer, the second layer is a fluorine-doped silicon-dioxide quartz glass layer, a relative refractive index difference Δ

32 thereof is −

0.01% to −

0.05%, and a diameter D32 thereof is 30 μ

m to 50 μ

m; and

a third layer closely surrounds the second layer, the third layer is a pure silicon-dioxide quartz glass layer, and a diameter D33 thereof is 124 μ

m to 126 μ

m.

2. The bend-insensitive single mode optical fiber according to claim 1, wherein the relative refractive index difference Δ

32 of the second layer is larger than the relative refractive index difference Δ

31 of the first layer.

3. The bend-insensitive single mode optical fiber according to claim 1, wherein a cut-off wavelength of the optical fiber is 1180 nm to 1360 nm.

4. The bend-insensitive single mode optical fiber according to claim 1, wherein a MFD of the optical fiber is 8 μ

m to 11 μ

m in a wavelength range of 1310 nm to 1550 nm.

5. The bend-insensitive single mode optical fiber according to claim 1, wherein attenuation of the optical fiber is less than or equal to 0.35 dB/km in a wavelength range of 1310 nm to 1550 nm.

6. The bend-insensitive single mode optical fiber according to claim 1, wherein a macro-bending loss of the optical fiber is less than or equal to 0.5 dB/(Φ

20 mm-1 circle) in a wavelength range of 1310 nm to 1550 nm.

7. The bend-insensitive single mode optical fiber according to claim 1, wherein a loss of the optical fiber in a fused biconical taper process is less than or equal to 0.1 dB.

8. The bend-insensitive single mode optical fiber according to claim 7, wherein device isolation of the optical fiber is larger than or equal to 20 dB.

9. The bend-insensitive single mode optical fiber according to claim 1, wherein the optical fiber is formed by way of fusing and wire-drawing with a wire-drawing speed no larger than 800 m/min and a wire-drawing coating tension of 200 g to 260 g.

10. The bend-insensitive single mode optical fiber according to claim 1, wherein in the first layer, a range of Δ

Ge is 0.05% to 0.25%, and a range of Δ

F is −

0.05% to −

0.30%.

11. The bend-insensitive single mode optical fiber according to claim 10, wherein the relative refractive index difference Δ

32 of the second layer is larger than the relative refractive index difference Δ

31 of the first layer.

12. The bend-insensitive single mode optical fiber according to claim 10, wherein a cut-off wavelength of the optical fiber is 1180 nm to 1360 nm.

13. The bend-insensitive single mode optical fiber according to claim 10, wherein a MFD of the optical fiber is 8 μ

m to 11 μ

m in a wavelength range of 1310 nm to 1550 nm.

14. The bend-insensitive single mode optical fiber according to claim 10, wherein attenuation of the optical fiber is less than or equal to 0.35 dB/km in a wavelength range of 1310 nm to 1550 nm.

15. The bend-insensitive single mode optical fiber according to claim 10, wherein a macro-bending loss of the optical fiber is less than or equal to 0.5 dB/(Φ

20 mm-1 circle) in a wavelength range of 1310 nm to 1550 nm.

16. The bend-insensitive single mode optical fiber according to claim 10, wherein a loss of the optical fiber in a fused biconical taper process is less than or equal to 0.1 dB.

17. The bend-insensitive single mode optical fiber according to claim 16, wherein device isolation of the optical fiber is larger than or equal to 20 dB.

18. The bend-insensitive single mode optical fiber according to claim 10, wherein the optical fiber is formed by way of fusing and wire-drawing with a wire-drawing speed no larger than 800 m/min and a wire-drawing coating tension of 200 g to 260 g.