Fiber optic cable

• US 8,548,293 B2
• Filed: 05/28/2009
• Issued: 10/01/2013
• Est. Priority Date: 05/28/2008
• Status: Expired due to Fees

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Kachmar, Wayne M.
• Primary Examiner(s): KIM, ELLEN E
• Application Number:
  US12/473,931
• Publication Number:
  US 20090297104A1
• Time in Patent Office: 1,587 Days
• Field of Search: 385/100, 385/101, 385/86, 385/87, 264/1.28, 264/1.29
• US Class Current: 385/101
• CPC Class Codes: G02B 6/02395 Glass optical fibre with a protective coating, e.g. two layer polymer coating deposited directly on a silica cladding surface during fibre manufacture G02B6/02052, G02B6/02057, G02B6/024, G02B6/032, G02B6/105, G02B6/14 take precedence; coating on fibre gratings G02B6/02104; multilayer core or cladding G02B6/036; reinforcing splice joints G02B6/2558; optical cables, i.e. comprising protective structures external to the protective coating such as a jacket or plural coated optical fibres G02B6/44; coating of glass to obtain optical fibres C03C25/104
• CPC Class Codes: G02B 6/03633 arranged - -
• CPC Class Codes: G02B 6/0365 arranged - - +
• CPC Class Codes: G02B 6/4402 with one single optical waveguide 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 6/4432 with fibre reinforcements
• CPC Class Codes: G02B 6/4433 Double reinforcement laying in straight line with optical transmission element
• CPC Class Codes: G02B 6/44382 the means comprising hydrogen absorbing materials G02B6/4439, G02B6/4479 take precedence
• CPC Class Codes: G02B 6/4486 Protective covering

Abstract

A fiber optic cable includes an optical fiber, a strength layer surrounding the optical fiber, and an outer jacket surrounding the strength layer. The strength layer includes a matrix material in which is integrated a plurality of reinforcing fibers. A fiber optic cable includes an optical fiber, a strength layer, a first electrical conductor affixed to an outer surface of the strength layer, a second electrical conductor affixed to the outer surface of the strength layer, and an outer jacket. The strength layer includes a polymeric material in which is embedded a plurality of reinforcing fibers. A method of manufacturing a fiber optic cable includes mixing a base material in an extruder. A strength layer is formed about an optical fiber. The strength layer includes a polymeric film with embedded reinforcing fibers disposed in the film. The base material is extruded through an extrusion die to form an outer jacket.

Claims

1. A fiber optic cable comprising:

a single bend-insensitive optical fiber that extends along a length of the fiber optic cable, the optical fiber including a first cladding layer surrounding a core, a trench layer surrounding the first cladding layer, a second cladding layer surrounding the trench layer, and a coating layer surrounding the second cladding layer, the coating layer having an outer diameter less than 500 μ

m;

a strength layer including a sheet-like reinforcing structure, the sheet-like reinforcing structure surrounding-the single bend-insensitive optical fiber to form a cylindrical reinforcing tube, the sheet-like reinforcing structure having longitudinal edges that overlap each other along a longitudinal seam, the reinforcing tube extending along the length of the fiber optic cable; and

an outer jacket surrounding the sheet-like reinforcing structure, the outer jacket having an outer diameter less than 1.6 mm, and the outer jacket extending along the length of the fiber optic cable; and

the fiber optic cable having a construction with no buffer layer positioned between the coating layer of the single bend-insensitive optical fiber and the sheet-like reinforcing structure, wherein the reinforcing tube formed by the sheet-like reinforcing structure defines a longitudinal bore for receiving the single bend-insensitive optical fiber, and wherein the reinforcing tube defined by the sheet-like reinforcing structure contacts the coating layer of the single bend-insensitive optical fiber and is configured to separate the single bend-insensitive optical fiber from the outer jacket;

wherein the sheet-like reinforcing structure includes aramid yarns held together by a matrix material that maintains a distribution of the aramid yards around the single bend-insensitive optical fiber, and wherein the matrix material of the sheet-like reinforcing structure is bonded to an inner diameter of the outer jacket.

2. A fiber optic cable as claimed in claim 1, wherein the outer jacket includes a base material and a shrinkage reduction material.

3. A fiber optic cable as claimed in claim 2, wherein the shrinkage reduction material is liquid crystal polymer.

4. A fiber optic cable as claimed in claim 1, wherein the plurality of aramid yarns extends a length of the strength layer.

5. A fiber optic cable as claimed in claim 1, wherein first and second axial ends of the strength layer are not rotationally offset from each other.

6. A fiber optic cable as claimed in claim 1, wherein the outer jacket is wider along a major axis of the outer jacket than along a minor axis of the outer jacket, the outer jacket surrounding the strength layer and defining a channel disposed at a lengthwise axis of the outer jacket through which the single bend-insensitive optical fiber passes, the outer jacket comprising a first portion disposed on a first side of the channel and a second portion disposed on an opposite side of the channel, wherein the major axis and the minor axis intersect perpendicularly at the lengthwise axis of the outer jacket.

7. A fiber optic cable as claimed in claim 6, wherein the strength layer has a width and a height and the strength layer is disposed within the first portion of the outer jacket such that the major axis bisects the height of the strength layer and is generally parallel to the width of the strength layer.

8. A fiber optic cable as claimed in claim 7, wherein the width of the strength layer is greater than the height of the strength layer.

12. A fiber optic cable as claimed in claim 1, wherein the outer diameter of the outer jacket is less than or equal to about 1.2 millimeters.

13. A fiber optic cable as claimed in claim 1, wherein the outer jacket has a non-circular transverse cross-sectional shape.

14. A fiber optic cable as claimed in claim 1, wherein the outer jacket has a circular transverse cross-sectional shape.

15. A fiber optic cable as claimed in claim 1, wherein the aramid yarns are embedded in the matrix material.

18. The fiber optic cable of claim 1, wherein the jacket includes polyvinyl chloride and wherein the outer diameter of the outer jacket is less than or equal to about 1.2 mm.

19. The fiber optic cable of claim 1, wherein the longitudinal seam does not helically rotate as the longitudinal seam extends along the length of the fiber optic cable.

20. The fiber optic cable of claim 1, wherein the outer diameter of the coating layer is less than or equal to 250 microns.

21. The fiber optic cable of claim 20, wherein the outer diameter of the outer jacket is less than or equal to about 1.2 mm.

9. A method for manufacturing a fiber optic cable including a bend insensitive optical fiber including a first cladding layer surrounding a core, a trench layer surrounding the first cladding layer, a second cladding layer surrounding the trench layer, and a coating layer surrounding the second cladding layer, the coating layer having an outer diameter less than 500 μ

m, a strength layer formed by a reinforcing sheet including a plurality of tensile reinforcing fibers held together by a matrix material, and an outer jacket, the method comprising;

shaping the reinforcing sheet around the bend insensitive optical fiber from a flat configuration into a cylindrical reinforcing tube having an outer diameter less than 1.2 mm by passing the bend insensitive optical fiber and the reinforcing sheet through a longitudinal folding tool where the reinforcing sheet is shaped about the bend insensitive fiber such that no buffer layer is positioned between the bend insensitive optical fiber and the cylindrical reinforcing tube;

forming the outer jacket about the cylindrical reinforcing tube by extruding a thermoplastic material about the cylindrical reinforcing tube such that the outer jacket has an outer diameter less than 1.6 mm; and

thermally bonding the thermoplastic material to the matrix material during extrusion of the outer jacket about the cylindrical reinforcing tube.

10. A method for manufacturing a fiber optic cable as claimed in claim 9, further comprising shaping the reinforcing sheet around the bend insensitive optical fiber so that first and second longitudinal edges of the reinforcing sheet are helically disposed along a length of the reinforcing sheet.

11. A method for manufacturing a fiber optic cable as claimed in claim 9, wherein extruding the thermoplastic material comprises extruding the thermoplastic material such that the outer jacket is wider along a major axis of the outer jacket than along a minor axis of the outer jacket, wherein the major axis and the minor axis intersect perpendicularly at a lengthwise axis of the outer jacket.

16. A method for manufacturing a fiber optic cable as claimed in claim 9, further comprising forming the reinforcing sheet from a matrix material and aramid yarns.

17. A method for manufacturing a fiber optic cable as claimed in claim 16, wherein the aramid yarns are embedded in the matrix material.