Large effective area low attenuation optical fiber

• US 8,218,929 B2
• Filed: 01/21/2010
• Issued: 07/10/2012
• Est. Priority Date: 02/26/2009
• Status: Expired due to Fees

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Bickham, Scott Robertson, Li, Ming-Jun
• Primary Examiner(s): Hahm, Sarah
• Application Number:
  US12/691,174
• Publication Number:
  US 20100215329A1
• Time in Patent Office: 901 Days
• Field of Search: 385/123, 385/126, 385/127
• US Class Current: 385/127
• CPC Class Codes: G02B 6/02019 Effective area greater than 90 square microns in the C band, i.e. 1530-1565 nm
• CPC Class Codes: G02B 6/02266 Positive dispersion fibres at 1550 nm
• CPC Class Codes: G02B 6/02357 Property of longitudinal structures or background material varies radially and/or azimuthally in the cladding, e.g. size, spacing, periodicity, shape, refractive index, graded index, quasiperiodic, quasicrystals
• CPC Class Codes: G02B 6/02366 Single ring of structures, e.g. "air clad"
• CPC Class Codes: G02B 6/0365 arranged - - +
• CPC Class Codes: G02B 6/03661 having 4 layers only

Abstract

Optical waveguide fiber that has large effective area and low loss characteristics, such as low attenuation and low bend loss. The optical waveguide fiber includes a dual trench design wherein an annular region closer to the core is preferably doped with at least one downdopant such as fluorine, which annular region is surrounded by another annular region that preferably includes closed, randomly dispersed voids.

Claims

1. An optical fiber comprising:

a glass core extending from a centerline to a radius R₁, wherein R₁ is greater than about 5 μ

m;

a glass cladding surrounding and in contact with the core;

wherein the cladding comprises;

a first annular region extending from the radius R₁ to a radius R₂, the first annular region comprising a radial width W₁=R₂−

R₁;

a second annular region extending from the radius R₂ to a radius R₃, the second annular region comprising a radial width W₂=R₃−

R₂;

a third annular region extending from the radius R₃ to a radius R₄, the third annular region comprising a radial width W₃=R₄−

R₃; and

a fourth annular region extending from the radius R₄ to an outermost glass radius R₅;

wherein the core comprises a maximum relative refractive index, Δ

_0MAX, the second annular region comprises a minimum relative refractive index, Δ

_2MIN, and the third annular region comprises a minimum relative refractive index, Δ

_3MIN, wherein Δ

_0MAX>

0>

Δ

_2MIN>

Δ

_3MIN; and

wherein the core and the cladding provide a fiber with cable cutoff less than 1500 nm and an effective area at 1550 nm of greater than 130 μ

m².

2. The optical fiber of claim 1, wherein 0.3%>

Δ

_0MAX>

0.1%, −

0.1%>

Δ

_2MIN>

−

0.5%, and Δ

_3MIN<

−

0.7%.

3. The optical fiber of claim 1, wherein 6 μ

m<

R₁<

9 μ

m, 10 μ

m<

R₂<

15 μ

m, 16 μ

m<

R₃<

24 μ

m, and 20 μ

m<

R₄<

30 μ

m.

4. The optical fiber of claim 1, wherein 2 μ

m<

W₁<

10 μ

m, 3 μ

m<

W₂<

15 μ

m, and 1.5 μ

m<

W₃<

4.5 μ

m.

5. The optical fiber of claim 1, wherein the second annular region comprises fluorine and is void-free.

6. The optical fiber of claim 1, wherein the third annular region comprises silica based glass with at least 50 closed randomly dispersed voids situated therein, and (i) the mean distance between the voids is less than 5000 nm, and (ii) at least 80% of the voids have a maximum cross-sectional dimension Di of less than 1000 nm.

7. The optical fiber of claim 1, wherein the second annular region comprises a profile volume V₂, equal to:

8. The optical fiber of claim 1, wherein the core and the cladding provide a fiber having an attenuation at 1550 nm of less than 0.19 dB/km.

9. The optical fiber of claim 1, wherein the core and the cladding provide a fiber with an effective area at 1550 nm of greater than 150 μ

m².

10. The optical fiber of claim 1, wherein the core and the cladding provide a fiber with a bend loss at 1550 nm of less than 1.0 dB/turn on a 20 mm diameter mandrel.

11. An optical fiber comprising:

a glass core extending from a centerline to a radius R₁, wherein R₁ is greater than about 5 μ

m;

a glass cladding surrounding and in contact with the core;

wherein the cladding comprises;

a first annular region extending from the radius R₁ to a radius R₂, the first annular region comprising a radial width W₁=R₂−

R₁;

a second annular region extending from the radius R₂ to a radius R₃, the second annular region comprising a radial width W₂=R₃−

R₂;

a third annular region extending from the radius R₃ to an outermost glass radius R₄;

wherein the core comprises a maximum relative refractive index, Δ

_0MAX, the first annular region comprises a minimum relative refractive index, Δ

_1MIN, and the second annular region comprises a minimum relative refractive index, Δ

_2MIN, wherein Δ

_0MAX>

0>

Δ

_1MIN>

Δ

_2MIN; and

wherein the core and the cladding provide a fiber with cable cutoff less than 1500 nm, an attenuation at 1550 nm of less than 0.20 dB/km, and an effective area at 1550 nm of greater than 130 μ

m²; and

wherein the second annular region comprises silica based glass with at least 50 closed randomly dispersed voids situated therein, and (i) the mean distance between the voids is less than 5000 nm, and (ii) at least 80% of the voids have a maximum cross-sectional dimension Di of less than 1000 nm.

12. The optical fiber of claim 11, wherein 0.3%>

Δ

_0MAX>

0.1%, −

0.1%>

Δ

_1MIN>

−

0.5%, and Δ

_2MIN<

−

0.7%.

13. The optical fiber of claim 11, wherein 6 μ

m<

R₁<

9 μ

m, 16 μ

m<

R₂<

24 μ

m, and 20 μ

m<

R₃<

30 μ

m.

14. The optical fiber of claim 11, wherein 3 μ

m<

W₁<

15 μ

m and 1.5 μ

m<

W₂<

4.5 μ

m.

15. The optical fiber of claim 11, wherein the first annular region comprises fluorine and is void-free.

16. The optical fiber of claim 11, wherein the first annular region comprises a profile volume V₁, equal to:

17. The optical fiber of claim 11, wherein the core and the cladding provide a fiber having an attenuation at 1550 nm of less than 0.19 dB/km.

18. The optical fiber of claim 11, wherein the core and the cladding provide a fiber with an effective area at 1550 nm of greater than 150 μ

m².

19. The optical fiber of claim 11, wherein the core and the cladding provide a fiber with a bend loss at 1550 nm of less than 1.0 dB/turn on a 20 mm diameter mandrel.