LOW BEND LOSS OPTICAL FIBER

• US 20100158460A1
• Filed: 12/15/2009
• Published: 06/24/2010
• Est. Priority Date: 12/19/2008
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Gwangju Institute of Science and Technology, Sehf-Korea Co., Ltd.
• Inventors: HAN, Won-Taek, JU, Seong-Min, KIM, Jin-Han, YOON, Young-Sik, LEE, Yeong-Seop, OH, Dea-Hwan
• Granted Patent: US 8,081,854 B2
• Time in Patent Office: Days
• US Class Current: 385/124
• CPC Class Codes: G02B 6/0283 Graded index region external to the central core segment, e.g. sloping layer or triangular or trapezoidal layer G02B6/0288, G02B6/0286 take precedence
• CPC Class Codes: G02B 6/0285 Graded index layer adjacent to the central core segment and ending at the outer cladding index
• CPC Class Codes: G02B 6/03627 arranged - +
• CPC Class Codes: G02B 6/0365 arranged - - +

Abstract

Disclosed is a low bend loss optical fiber including: a core; an inner layer disposed at outside of the core, which has a refractive index lower than a refractive index of the core, the refractive index of the inner layer gradually decreasing as it becomes farther from the core; and a trench layer disposed at outside of the inner layer, which has a lowest refractive index.

Claims

1. A low bend loss optical fiber comprising:

a core;

an inner layer disposed at outside of the core, which has a refractive index lower than a refractive index of the core, the refractive index of the inner layer gradually decreasing as it becomes farther from the core; and

a trench layer disposed at outside of the inner layer, which has a lowest refractive index.

2. The low bend loss optical fiber as claimed in claim 1, further comprising an outer layer disposed at outside of the trench layer, which has a refractive index that is higher than the lowest refractive index of the trench layer and lower than the refractive index of the core.

3. The low bend loss optical fiber as claimed in claim 1, wherein the trench layer has a portion where a refractive index gradually increases as it becomes farther from the core.

4. The low bend loss optical fiber as claimed in claim 1, wherein the trench layer comprises:

a first trench sub layer whose refractive index gradually decreases it becomes farther from the core; and

a second trench sub layer whose refractive index gradually increases it becomes farther from the core.

5. The low bend loss optical fiber as claimed in claim 1, wherein the inner layer comprises:

a first inner sub layer whose refractive index gradually decreases it becomes farther from the core; and

a second inner sub layer whose refractive index is fixed.

6. The low bend loss optical fiber as claimed in claim 1, wherein a refractive index difference between the core and the inner layer is in a range from 0.0040 to 0.0065.

7. The low bend loss optical fiber as claimed in claim 1, wherein a diameter of the core is in a range from 6.0 μ

m to 9.5 μ

m.

8. The low bend loss optical fiber as claimed in claim 1, wherein a refractive index difference of the inner layer and the trench layer is in a range from −

0.001 to 0.003.

9. The low bend loss optical fiber as claimed in claim 1, wherein a thickness of the inner layer is 16 μ

m or less.

10. The low bend loss optical fiber as claimed in claim 1, wherein a refractive index difference between the trench layer and the outer layer is −

0.003 or less.

11. The low bend loss optical fiber as claimed in claim 1, wherein a thickness of the trench layer is 14 μ

m or less.

12. The low bend loss optical fiber as claimed in claim 1, wherein the low bend loss optical fiber has a bending loss of 1.0 dB/turn or less at wavelengths of 1550 nm and 1625 nm when the low bend loss optical fiber is bent with a radius of 5 mm.

13. A low bend loss optical fiber comprising:

a core;

an inner layer disposed at outside of the core, which has a refractive index lower than a refractive index of the core; and

a trench layer disposed at outside of the inner layer, which has a lowest refractive index, and has a portion where a refractive index gradually increases as it becomes farther from the core.

14. The low bend loss optical fiber as claimed in claim 13, further comprising an outer layer disposed at outside of the trench layer, which has a refractive index that is higher than the lowest refractive index of the trench layer and lower than the refractive index of the core.

15. The low bend loss optical fiber as claimed in claim 13, wherein the inner layer has a portion where the refractive index gradually decreases as it becomes farther from the core.

16. The low bend loss optical fiber as claimed in claim 13, wherein the trench layer comprises:

a first trench sub layer whose refractive index gradually decreases as it becomes farther from the core; and

a second trench sub layer whose refractive index gradually increases as it becomes farther from the core.

17. The low bend loss optical fiber as claimed in claim 13, wherein the inner layer comprises:

a first inner sub layer whose refractive index gradually decreases it becomes farther from the core; and

a second inner sub layer whose refractive index is fixed.