Termination of fiber optic cable
Apparatus and methods provide for cables with secured terminations. For some embodiments, a cable includes an inner tube surrounding an optical fiber, an aluminum tube surrounding the inner tube, and armor tubing surrounding the aluminum tube. The aluminum tube resists collapse of the inner tube at bends in the cable, inhibits or prevents hydrogen from reaching the fiber, and facilitates termination of the cable. For example, terminating the cable may include crimping the armor tubing to deform the aluminum tube into gripping engagement with an outside of the inner tube and an inside of the armor tubing. In some embodiments, a retention assembly secures the fiber relative to the inner tube and includes a retention tube secured to the inner tube and a packing sleeve squeezed into gripping engagement with the fiber by radial inward deformation of the retention tube where the packing sleeve is disposed in the retention tube.
1. A method of preparing a cable with a secured termination, comprising:
providing the cable comprising an inner tube having an optical fiber disposed inside the inner tube;
removing a portion of the inner tube at an end of the cable to expose a length of the optical fiber extending from an end of the inner tube;
positioning an elastomeric packing sleeve surrounding at least part of the length of the optical fiber adjacent the end of the inner tube;
positioning a retention tube overlapping outsides of both the inner tube and the elastomeric packing sleeve;
securing the retention tube to the inner tube; and
deforming the retention tube in a radial inward direction where the packing sleeve is disposed in the retention tube to squeeze the packing sleeve into gripping engagement with the optical fiber.
2. The method of claim 1 , wherein securing the retention tube to the inner tube includes crimping the retention tube against the outside of the inner tube.
3. The method of claim 1 , further comprising crimping a section of armor tubing to secure the armor tubing, an aluminum tube and the inner tube relative to one another, wherein the cable further comprises the aluminum tube surrounding the inner tube and the armor tubing surrounding the aluminum tube.
4. The method of claim 1 , wherein the elastomeric packing sleeve comprises silicone.
5. The method of claim 1 , further comprising positioning a tubular protective insert into the end of the inner tube.
6. The method of claim 1 , further comprising positioning a first end of a tubular protective insert into the end of the inner tube, wherein a second end of the insert is received in a body that is adjacent the end of the inner tube and has a larger outer diameter than the insert.
7. A cable with a secured termination, comprising:
an optical fiber;
an inner tube surrounding the optical fiber, wherein a length of the optical fiber extends from an end of the inner tube;
an elastomeric packing sleeve surrounding at least part of the length of the optical fiber adjacent the end of the inner tube; and
a retention tube overlapping outsides of both the inner tube and the elastomeric packing sleeve, wherein the retention tube is secured to the inner tube and the retention tube is deformed in a radial inward direction where the packing sleeve is disposed in the retention tube to squeeze the packing sleeve into gripping engagement with the optical fiber.
8. The cable of claim 7 , wherein the elastomeric packing sleeve comprises silicone.
9. The cable of claim 7 , further comprising:
an aluminum tube surrounding the inner tube; and
armor tubing surrounding the aluminum tube, wherein a section of the armor tubing is crimped to secure the armor tubing, the aluminum tube and the inner tube relative to one another.
10. The cable of claim 7 , wherein the aluminum tube is formed of extruded material and is thereby seamless.
11. The cable of claim 7 , wherein the retention tube is secured to the inner tube by a crimp in the retention tube that presses the retention tube against the outside of the inner tube.
12. The cable of claim 7 , wherein the inner tube and the retention tube are both made of metallic material.
13. The cable of claim 7 , further comprising:
a metal tube surrounding the inner tube; and
armor tubing surrounding the metal tube and crimped to secure the armor tubing, the metal tube and the inner tube relative to one another, wherein the metal tube is made of a material more ductile than the inner tube and the armor tubing.
14. The cable of claim 7 , further comprising:
a metal tube surrounding the inner tube; and
armor tubing surrounding the metal tube and crimped to secure the armor tubing, the metal tube and the inner tube relative to one another, wherein the metal tube is made of a material more impermeable to hydrogen than the inner tube and the armor tubing.