Fiber optic cable with bend preference

• US 9,081,163 B2
• Filed: 04/29/2014
• Issued: 07/14/2015
• Est. Priority Date: 01/20/2012
• Status: Active Grant

• Current Assignee: Corning Optical Communications LLC (Corning Incorporated)
• Original Assignee: Corning Optical Communications LLC (Corning Incorporated)
• Inventors: Bradley, Mark Alan, McCollough, William Welch, Register, James Arthur III
• Primary Examiner(s): Ullah, Akm Enayet
• Application Number:
  US14/264,134
• Publication Number:
  US 20150160425A1
• Time in Patent Office: 441 Days
• US Class Current: 1/1
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence
• CPC Class Codes: G02B 6/4214 the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device G02B6/4246 takes precedence
• CPC Class Codes: G02B 6/4403 with ribbon structure G02B6/4429, G02B6/4439, G02B6/4479 take precedence
• CPC Class Codes: G02B 6/4429 Means specially adapted for strengthening or protecting the cables
• CPC Class Codes: G02B 6/443 Protective covering
• CPC Class Codes: G02B 6/4431 with provision in the protective covering, e.g. weak line, for gaining access to one or more fibres, e.g. for branching or tapping break-out terminations G02B6/4471
• CPC Class Codes: G02B 6/4433 Double reinforcement laying in straight line with optical transmission element
• CPC Class Codes: G02B 6/4472 Manifolds

Abstract

A fiber optic cable includes a polymeric jacket, an optical fiber, and first and second longitudinal strength elements. The jacket defines an outer periphery and a cavity interior thereto. The cavity is elongate and the outer periphery is polygonal. The optical fiber is positioned within the cavity of the jacket. The first and second longitudinal strength elements are embedded in the jacket on an opposite sides of the cavity from one another. The cable resists bending in a non-preferential plane by no more than five times as much as the cable resists bending in a preferential plane.

Claims

1. A fiber optic cable, comprising:

a polymeric jacket defining an outer periphery and a cavity interior thereto, wherein the cavity is elongate, and wherein the outer periphery is polygonal;

an optical fiber positioned within the cavity of the jacket;

a first longitudinal strength element embedded in the jacket; and

a second longitudinal strength element embedded in the jacket on an opposite side of the cavity from the first strength longitudinal member,

wherein the first and second longitudinal strength elements define a bend axis of the cable passing through the strength elements that is orthogonal to the length of the cable, whereby the bend axis and the length of the cavity define a preferential plane for bending, wherein the cable resists bending about a third axis that is orthogonal to the length of the cable and also orthogonal to the bend axis, whereby the third axis and the length of the cable define a non-preferential plane for bending;

wherein the cable resists bending in the non-preferential plane by no more than five times as much as the cable resists bending in the preferential plane.

2. The fiber optic cable of claim 1, wherein the cable resists bending in the non-preferential plane by at least twice as much as the cable resists bending in the preferential plane, but wherein the cable resists bending in the non-preferential plane by no more than four times as much as the cable resists bending in the preferential plane.

3. The fiber optic cable of claim 1, wherein the flexural rigidity of each strength member is less than 200 Nm².

4. The fiber optic cable of claim 1, wherein the first and second longitudinal strength elements consist of stranded stainless steel.

5. The fiber optic cable of claim 1, further comprising at least another optical fiber in the cavity, wherein the optical fibers are configured to move within the cavity and configured to move relative to one another.

6. The fiber optic cable of claim 5, wherein the largest dimensions of the outer periphery orthogonal to the length of the cable is less than three millimeters.

7. The fiber optic cable of claim 6, wherein when the cable is fully bent back upon itself about the bend axis, the bend radius of the optical fiber in the cavity is greater than or equal to 1.5 millimeters.

8. The fiber optic cable of claim 5, wherein when the cable is fully bent back upon itself about the bend axis, the bend diameter of the optical fiber in the cavity is greater than the largest dimensions of the outer periphery orthogonal to the length of the cable.

9. The fiber optic cable of claim 5, wherein the cavity is asymmetric and includes a single portion closer to the exterior of the cable than any other portion of the cavity.

10. The fiber optic cable of claim 9, further comprising a single access member embedded in the jacket between the single portion of the cavity and the exterior of the cable.

11. The fiber optic cable of claim 10, wherein the single access member is a ripcord.

12. The fiber optic cable of claim 5, further comprising a co-extruded discontinuity of material in the jacket between the single portion of the cavity and the exterior of the cable.

13. The fiber optic cable of claim 12, wherein the jacket comprises a first material and the co-extruded discontinuity of material in the jacket comprises a second material different than the first material but comprising the first material.

14. The fiber optic cable of claim 5, wherein the optical fibers are tight buffered.

15. The fiber optic cable of claim 5, wherein the cable is round in cross-section.

16. The fiber optic cable of claim 5, wherein the cable only includes two strength members embedded in the jacket.

17. The fiber optic cable of claim 16, wherein the strength members are formed from a dielectric material.

18. The fiber optic cable of claim 17, wherein the strength members comprise a polymer.

19. A fiber optic cable, comprising:

a polymeric jacket defining an outer periphery and a cavity interior thereto, wherein the cavity is elongate, wherein the largest dimensions of the outer periphery orthogonal to the length of the cable is less than three millimeters, and wherein the outer periphery is polygonal;

an optical fiber positioned within the cavity of the jacket;

a first longitudinal strength element fully embedded in the jacket; and

a second longitudinal strength element fully embedded in the jacket on an opposite side of the cavity from the first strength longitudinal member.

20. The fiber optic cable of claim 19, wherein the first and second longitudinal strength elements define a bend axis of the cable passing through the strength elements that is orthogonal to the length of the cable, whereby the bend axis and the length of the cavity define a preferential plane for bending, wherein the cable resists bending about a third axis that is orthogonal to the length of the cable and also orthogonal to the bend axis, whereby the third axis and the length of the cable define a non-preferential plane for bending;

wherein the cable resists bending in the non-preferential plane by at least twice as much as the cable resists bending in the preferential plane, but wherein the cable resists bending in the non-preferential plane by no more than five times as much as the cable resists bending in the preferential plane.