Non-round filler rods and tubes with superabsorbent water swellable material for large cables

• US 20040076386A1
• Filed: 10/17/2002
• Published: 04/22/2004
• Est. Priority Date: 10/17/2002
• Status: Active Grant

• Current Assignee: Draka Comteq BV (Prysmian SPA)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Nechitailo, Nicholas V.
• Granted Patent: US 6,922,512 B2
• Time in Patent Office: Days
• US Class Current: 385/100
• CPC Class Codes: G02B 6/4411 Matrix structure
• CPC Class Codes: G02B 6/44384 the means comprising water blocking or hydrophobic materials G02B6/4439, G02B6/4479 take precedence

Abstract

A fiber optic cable having a plurality of buffer tubes and filler rods or filler tubes disposed between the inner surface of the outer jacket of the fiber optic cable and the buffer tubes. The buffer tubes contain a plurality of optical fibers. The filler rods have a non-round core surrounded by a suberabsorbant water swellable coating to provide protection for the optical fibers against the penetration of water within the cable. The filler rods and filler tubes are made of a solid or porous or foam-type material expanding in the presence of water.

Claims

1. A filler rod for use in a fiber optic cable comprising:

a core; and

a water swellable coating surrounding said core,

wherein said core is non-round in cross-sectional shape.

2. The filler rod of claim 1, wherein said core is made of solid or porous polymeric material.

3. The filler rod of claim 1, wherein said core is made of a thermoplastic material.

4. The filler rod of claim 1, wherein said core is made of yarn.

5. The filler rod of claim 1, wherein said core is substantially triangular in cross-sectional shape.

6. The filler rod of claim 1, wherein said core is substantially trapezoidal in cross-sectional shape.

7. The filler rod of claim 1, wherein said filler rod is non-round in cross-sectional shape.

8. The filler rod of claim 1, wherein said filler rod has a cross-sectional shape corresponding to a cross-sectional shape of interstitial gaps within said fiber optic cable.

9. A filler rod for use in a fiber optic cable wherein said filler rod is formed of a water swellable material having a non-round cross-sectional shape.

10. The filler rod of claim 9, wherein said filler rod has a cross-sectional shape corresponding to a cross-sectional shape of an interstitial gap within said fiber optic cable.

11. The filler rod of claim 9, wherein said filler rod is hollow or tubular having water swellable material.

12. A fiber optic cable comprising:

an outer jacket;

a plurality of buffer tubes containing a plurality of optical fibers; and

at least one filler rod disposed between at least two of said plurality of buffer tubes and a neighboring structure,

wherein said at least one filler rod comprises;

a core; and

a water swellable coating surrounding said core,

wherein said core is non-round in cross-sectional shape.

13. The fiber optic cable of claim 12, wherein the neighboring structure is said outer jacket.

14. The fiber optic cable of claim 12, wherein said core is made of solid or porous polymeric material.

15. The fiber optic cable of claim 12, wherein said core is made of a thermoplastic material.

16. The fiber optic cable of claim 12, wherein said core is made of yarn.

17. The fiber optic cable of claim 12, wherein said at least one filler rod is non-round in cross-sectional shape.

18. The fiber optic cable of claim 12, wherein said at least one filler rod has a cross-sectional shape corresponding to a cross-sectional shape of interstitial gaps within said fiber optic cable.

19. A fiber optic cable comprising:

an outer jacket;

a plurality of buffer tubes containing a plurality of optical fibers; and

at least one filler rod disposed between at least two of said plurality of buffer tubes and said outer jacket, wherein said at least one filler rod is formed of a water swellable material having a non-round cross-sectional shape.

20. The fiber optic cable of claim 19, wherein said at least one filler rod has a cross-sectional shape corresponding to a cross-sectional shape of an interstitial gap within said fiber optic cable.

21. The fiber optic cable of claim 19, wherein said at least one filler rod is hollow or tubular having water swellable material.