Bend resistant multimode optical fiber

• US 7,787,731 B2
• Filed: 12/20/2007
• Issued: 08/31/2010
• Est. Priority Date: 01/08/2007
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Li, Ming-Jun, Bookbinder, Dana Craig, Nolan, Daniel Aloysius
• Primary Examiner(s): STAHL, MICHAEL J
• Application Number:
  US12/004,174
• Publication Number:
  US 20080166094A1
• Time in Patent Office: 985 Days
• Field of Search: None
• US Class Current: 385/124
• CPC Class Codes: C03B 2203/14 Non-solid, i.e. hollow products, e.g. hollow clad or with core-clad interface
• CPC Class Codes: C03B 2203/23 Double or multiple optical cladding profiles
• CPC Class Codes: C03B 2203/26 Parabolic or graded index [GRIN] core profile
• CPC Class Codes: C03B 2203/28 Large core fibres, e.g. with a core diameter greater than 60 micrometers
• CPC Class Codes: G02B 6/02333 Core having higher refractive index than cladding, e.g. solid core, effective index guiding
• CPC Class Codes: G02B 6/02342 characterised by cladding features, i.e. light confining region
• CPC Class Codes: G02B 6/0288 Multimode fibre, e.g. graded index core for compensating modal dispersion
• CPC Class Codes: G02B 6/032 with non solid core or cladding G02B6/02295 takes precedence
• CPC Class Codes: G02B 6/03627 arranged - +
• CPC Class Codes: G02B 6/03633 arranged - -
• CPC Class Codes: G02B 6/0365 arranged - - +
• CPC Class Codes: G02B 6/14 Mode converters

Abstract

Bend resistant multimode optical fibers are disclosed herein. Multimode optical fibers disclosed herein comprise a core region and a cladding region surrounding and directly adjacent to the core region, the cladding region comprising a depressed-index annular portion comprising a depressed relative refractive index.

Claims

1. A multimode optical fiber comprising:

a graded index multimode glass core having a radius greater than 20 microns and less than 28 microns and an alpha between 2.1 and 2.3; and

a glass cladding surrounding and in contact with the core, the cladding comprising a depressed-index annular portion which is spaced from said core;

wherein the fiber exhibits (a) a bandwidth of greater than 750 MHz-km at a wavelength of 850 nm, and (b) a 1 turn 10 mm diameter mandrel wrap attenuation increase at a wavelength of 1550 nm, in dB, of less than 1.5 dB.

2. The multimode optical fiber of claim 1 wherein the depressed-index annular portion comprises a profile volume with an absolute magnitude of greater than 100%-μ

m².

3. The multimode optical fiber of claim 2 wherein the cladding further comprises an outer cladding region having a higher index delta than said depressed region, and said core is parabolic in shape and ends where the core exhibits a refractive index delta which is substantially equal to that of the outer cladding region.

4. The multimode optical fiber of claim 2 wherein the depressed-index annular portion is offset from the core by at least 0.4 microns.

5. The multimode optical fiber of claim 2 wherein the depressed-index annular portion comprises a profile volume with an absolute magnitude of greater than 120%-μ

m².

6. The multimode optical fiber of claim 2 wherein the fiber is spun.

7. The multimode optical fiber of claim 2 wherein the restricted mode launch bandwidth is greater than 1 GHz-km at a wavelength of 850 nm.

8. The multimode optical fiber of claim 1 wherein said fiber exhibits a restricted mode launch bandwidth greater than 1.5 GHz-km at a wavelength of 850 nm.

9. The multimode optical fiber of claim 1 wherein said fiber exhibits a restricted mode launch bandwidth greater than 3 GHz-km at a wavelength of 850 nm.

10. The multimode fiber of claim 1, wherein said fiber comprises fluorine in the depressed-index annular portion.

11. The multimode optical fiber of claim 1 wherein said fiber exhibits a 1 turn 10 mm diameter mandrel wrap attenuation increase at a wavelength of 1550 nm, in dB, of less than 1.0 dB.

12. The multimode optical fiber of claim 2 wherein said fiber comprises fluorine in the depressed-index annular portion, and said core comprises a radius less than 27 microns.

17. The multimode optical fiber of claim 4, wherein the core and the cladding provide a bandwidth of greater than 3.0 GHz-km at a wavelength of 850 nm.

18. The multimode optical fiber of claim 4, wherein the depressed-index annular portion has a profile volume with an absolute magnitude of less than 200%-μ

m².

19. The multimode optical fiber of claim 17, wherein the depressed-index annular portion has a profile volume with an absolute magnitude of less than 200%-μ

m².

20. The multimode optical fiber of claim 8, wherein the depressed-index annular portion has a profile volume with an absolute magnitude of greater than 85%-μ

m².

21. The multimode optical fiber of claim 1, wherein the depressed-index annular portion has a profile volume with an absolute magnitude of less than 200%-μ

m².

13. A multimode optical fiber comprising:

a graded index multimode glass core having a radius greater than 20 microns and less than 28 microns; and

a glass cladding surrounding and in contact with the core, the cladding comprising a depressed-index annular portion which comprises a profile volume with an absolute magnitude of greater than 100%-μ

m², wherein the depressed-index annular region is offset from said core by at least 0.4 microns, and

wherein the fiber exhibits (a) a bandwidth of greater than 750 MHz-km at a wavelength of 850 nm, and (b) a 1 turn 10 mm diameter mandrel wrap attenuation increase at a wavelength of 1550 nm of less than 1.5 dB.

14. The multimode optical fiber of claim 13, wherein the fiber exhibits a 1 turn 10 mm diameter mandrel wrap attenuation increase at a wavelength of 1550 nm, in dB, of less than 1.0 dB.

15. The multimode optical fiber of claim 13, wherein said fiber comprises fluorine in the depressed-index annular portion, and said core comprises a radius less than 27 microns.

16. The multimode optical fiber of claim 13 wherein said fiber exhibits a restricted mode launch bandwidth greater than 3 GHz-km at a wavelength of 850 nm.

22. The multimode optical fiber of claim 13, wherein the core and the cladding provide a bandwidth of greater than 2.0 GHz-km at a wavelength of 850 nm.

23. The multimode optical fiber of claim 13, wherein the core and the cladding provide a bandwidth of greater than 3.0 GHz-km at a wavelength of 850 nm.