Fiber optic cable breakout configuration with “Y” block

• US 7,251,411 B1
• Filed: 07/21/2006
• Issued: 07/31/2007
• Est. Priority Date: 03/09/2006
• Status: Active Grant

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Lu, Yu, Millea, Keith, Gniadek, Jeff
• Primary Examiner(s): Bovernick; Rodney
• Assistant Examiner(s): ROJAS, OMAR R
• Application Number:
  US11/491,008
• Time in Patent Office: 375 Days
• Field of Search: None
• US Class Current: 385/147
• CPC Class Codes: G02B 6/4475 with provision for lateral branching G02B6/4431 takes precedence
• CPC Class Codes: G02B 6/4476 with heat-shrinkable elements

Abstract

The present disclosure relates to a telecommunications cable including a distribution cable and a tether that branches from the distribution cable at a mid-span breakout location. A flexible closure covers the mid-span breakout location. Within the closure, fibers are broken out from the distribution cable and spliced to fibers of the tether. The lengths of broken out fibers within the flexible closure are provided with sufficient excess fiber length to allow the closure to be readily bent/flexed in any direction without damaging the fibers.

Claims

1. A telecommunications cable comprising:

a distribution cable including a distribution cable jacket and a plurality of buffer tubes positioned within the cable jacket, the plurality of buffer tubes including a first buffer tube, the distribution cable including a mid-span location where a portion of the distribution cable jacket has been removed and where at least the first buffer tube includes a fiber access location;

a tether cable including a tether jacket, a tether buffer tube positioned within the jacket, and at least one strength member;

a retention block configured to install on the distribution cable at a downstream end of the mid-span location, the retention block configured to retain the tether buffer tube and the at least one strength member of the tether cable;

a separation block configured to install on the distribution cable at an upstream end of the mid-span location, the separation block including a first channel extending from a first end of the separation block to an opposite second end of the separation block, the plurality of buffer tubes of the distribution cable passing through the first channel, the separation block also including a second channel extending from the first channel to the second end of the separation block;

a tube that extends along the mid-span location from the separation block to the retention block;

a length of optical fiber optically coupled to the distribution cable at one end and optically coupled to the tether cable at an opposing end, the length of optical fiber passing through the second channel of the separation block, along the tube, and through the retention block; and

an overmold that covers the retention block, the separation block, and the tube.

2. The telecommunications cable of claim 1, wherein the separation block is generally Y-shaped.

3. The telecommunications cable of claim 1, wherein the separation block includes a first section and a second, opposing section.

4. The telecommunications cable of claim 3, wherein a mechanical interlock exists between the first section and the second opposing section.

5. The telecommunications cable of claim 4, wherein the mechanical interlock includes a depression defined in the first section and a protruding portion on the second opposite section.

6. The telecommunications cable of claim 1, wherein the separation block includes a first section including a first groove and a second groove, and a second section including a first groove and a second groove, and wherein the first groove of the first section aligns with the first groove of the second section to form the first channel of the separation block, and the second groove of the first section aligns with the second groove of the second section to form the second channel of the separation block.

7. The telecommunications cable of claim 1, wherein the telecommunications cable is sized to be pulled through a conduit having a 1.25 inch inner diameter.

8. The telecommunications cable of claim 1, wherein the tether is a stub cable or a drop cable.

9. The telecommunications cable of claim 1, further comprising a splice sleeve that surrounds a portion of the length of optical fiber, the splice sleeve configured to fit within the tube.

10. The telecommunications cable of claim 9, wherein the splice sleeve has a length of less than or equal to 30 mm.

11. The telecommunications cable of claim 9, wherein the splice sleeve has a length of less than about 35 mm.

12. The telecommunications cable of claim 1, wherein the separation block includes a first section, a second section, and a third section, each section having a substantially tubular shape, the first and second section forming opposing ends of the first channel, the third section forming an end of the second channel.

13. The telecommunications cable of claim 12, wherein the third section of the separation block is configured to fit within the tube.

14. The telecommunications cable of claim 1, wherein the retention block is mounted onto an outer strength member of the distribution cable.

15. The telecommunications cable of claim 1, wherein the length of optical fiber has an excess fiber length in the range of 2–

5 percent.

16. A telecommunications cable comprising:

a distribution cable including a cable jacket, a plurality of buffer tubes positioned within the cable jacket, and an outer strength member positioned about the plurality of buffer tubes, the plurality of buffer tubes including a first buffer tube, the distribution cable including a mid-span location where a portion of the cable jacket has been removed, where the outer strength member extends across the mid-span location, and where at least the first buffer tube includes a fiber access location;

a tether that branches from the distribution cable at the mid-span location, the tether including a tether jacket, a tether buffer tube positioned within the jacket, and at least one strength member also positioned within the jacket;

a separation block configured to install on the distribution cable, the separation block including a first channel extending from a first end of the separation block to an opposite second end of the separation block, where the first channel is configured to retain the plurality of buffer tubes of the distribution cable and not the outer strength member, the separation block also including a second channel extending from the first channel to the second end of the separation block;

a first optical fiber that extends through the first buffer tube of the distribution cable, the first buffer tube being routed through the first channel of the separation block, the first optical fiber being routed out of the first buffer tube through the fiber access location and through the second channel of the separation block;

a second optical fiber that extends through the tether buffer tube; and

the first optical fiber being spliced to the second optical fiber at a splice location to form a spliced length of fiber, the splice location located adjacent the mid-span location.

17. The telecommunications cable of claim 16, further comprising an overmold that covers the retention block, the separation block, and the tube.

18. The telecommunications cable of claim 16, wherein the telecommunications cable is sized to be pulled through a conduit having a 1.25 inch inner diameter.

19. The telecommunications cable of claim 16, wherein the spliced length of fiber has an excess fiber length in the range of 2–

5 percent.

20. A telecommunications cable comprising:

a distribution cable including a plurality of buffer tubes exposed at a mid-span location;

a tether that branches from the distribution cable at the mid-span location, the tether including a tether buffer tube and at least one strength member;

a separation block configured to install on the distribution cable at an upstream end of the mid-span location, the separation block including a first channel and a second channel, the first channel configured to retain the plurality of buffer tubes at the mid-span location;

a retention block configured to install on the distribution cable at a downstream end of the mid-span location, the retention block configured to retain the tether buffer tube and the at least one strength member of the tether;

a first optical fiber that extends through one of the plurality of buffer tubes of the distribution cable, the first optical fiber extending out of the buffer tube through the second channel of the separation block to a splice location;

a second optical fiber that extends through the tether buffer tube and through the retention block to the splice location, the first optical fiber being spliced to the second optical fiber at a splice location to form a spliced length of fiber;

a splice sleeve configured to enclose the spliced length of fiber at the splice location, the splice sleeve having a length extending less than 35 mm; and

a tube extending from the separation block to the retention block, the tube enclosing the splice sleeve.

21. The telecommunications cable of claim 20, wherein the splice sleeve is less than or equal to 30 mm.

22. The telecommunications cable of claim 20, wherein the spliced length of fiber has an excess fiber length in the range of 2–

5 percent.