Optical cable and manufacturing method
An optical cable including a load bearing core includes a longitudinally and radially extending slot housing at least one optical fiber, wherein the slot has a width providing a low clearance for the optical fiber(s) housed therein and preventing two optical fibers being stuck to one another; and the slot has a depth equal to or lower than a radius of the core.
1. An optical cable comprising a load bearing core comprising a longitudinally and radially extending slot housing an optical fibre,
wherein the slot has an opening and a width ranging from about 1.1 to 1.5 times a diameter of the optical fibre thereby providing a low clearance for the optical fibre housed therein and preventing the optical fibre being stuck to a second optical fibre when present; and
the slot has a depth equal to or less than a radius of the core;
and the core has a diameter of 3 mm at most; and
wherein a sheath is arranged in radial external position with respect to the core, an adhesive layer is interposed between the core and the sheath, and the adhesive layer does not comprise a tape.
2. The optical according to claim 1 , wherein the sheath is an extruded sheath.
3. The optical cable according to claim 1 , wherein the core has a substantially circular cross-section.
4. The optical cable according to claim 1 , wherein the core has a diameter at least four times the slot width.
5. The optical cable according to claim 1 , wherein the core is made of fibre reinforced plastic.
6. The optical cable according to claim 1 , wherein the core is made of a material having an elastic modulus of at least 40 GPa.
7. The optical cable according to claim 1 , wherein the core has a diameter greater than 1.9 mm.
8. The optical cable according to claim 1 , wherein the cable has a diameter ranging from 2.5 mm to 5 mm.
9. The optical cable according to claim 1 , wherein two optical fibres are housed in the slot.
10. The optical cable according to claim 1 , wherein the slot width is less than 1.3 times the optical fibre diameter.
11. The optical cable according to claim 1 , wherein the slot contains water swellable material.
12. The optical cable according to claim 1 , wherein the sheath is configured so that an indicium of the position of the slot in the core is present.
13. The optical cable according to claim 1 , comprising an additional longitudinally extended reinforcing structure.
14. A method of manufacturing an optical cable, comprising:
providing a load bearing core comprising a longitudinally and radially extending slot configured for housing an optical fibre, wherein the slot has an opening and a width ranging from about 1.1 to 1.5 times a diameter of the at least one optical fibre thereby providing a low clearance for the optical fibre housed therein and preventing the optical fibre being stuck to a second optical fibre when present, and wherein the slot has a depth equal to or less than a radius of the core, and wherein the core has a diameter of 3 mm at most;
housing the optical fibre in the slot;
winding the cable onto a coil while orienting the opening of the slot radially outwardly with respect to the coil;
applying a sheath over the core before winding the cable onto the coil; and
providing an adhesive layer interposed between the core and the sheath, wherein said adhesive layer does not comprise a tape.
15. The method according to claim 14 , wherein the sheath is applied by extrusion.
16. The optical cable according to claim 12 , wherein the indicium is a flattened longitudinally extended area of an outer surface of the sheath in correspondence with the slot longitudinal extension.
17. The optical cable according to claim 12 , wherein the indicium is a colored line.
18. The method according to claim 14 , further comprising the step of providing a water swellable material in the slot.
19. The method according to claim 14 , further comprising the step of providing an indicium of the position of the slot in the core, wherein the indicium is a flattened longitudinally extended area of an outer surface of the sheath in correspondence with the slot longitudinal extension or a colored line.
20. An optical cable comprising a load bearing core comprising a longitudinally and radially extending slot housing an optical fibre,
wherein the slot has an opening and a width ranging from about 1.1 to 1.5 times a diameter of the optical fibre thereby providing a low clearance for the optical fibre housed therein and preventing the optical fibre being stuck to a second optical fibre when present; and
the slot has a depth equal to or less than a radius of the core;
and the core has a diameter of 3 mm at most; and
wherein a sheath is arranged in radial external position with respect to the core, the sheath is configured so that an indicium of the position of the slot in the core is present, and the indicium is a flattened longitudinally extended area of an outer surface of the sheath in correspondence with the slot longitudinal extension.
21. The optical according to claim 20 , wherein the sheath is an extruded sheath.
22. The optical cable according to claim 20 , wherein the core has a substantially circular cross-section.
23. The optical cable according to claim 20 , wherein the core has a diameter at least four times the slot width.
24. The optical cable according to claim 20 , wherein the core is made of fibre reinforced plastic.
25. The optical cable according to claim 20 , wherein the core is made of a material having an elastic modulus of at least 40 GPa.
26. The optical cable according to claim 20 , wherein the core has a diameter greater than 1.9 mm.
27. The optical cable according to claim 20 , wherein the cable has a diameter ranging from 2.5 mm to 5 mm.
28. The optical cable according to claim 20 , wherein two optical fibres are housed in the slot.
29. The optical cable according to claim 20 , wherein the slot width is less than 1.3 times the optical fibre diameter.
30. The optical cable according to claim 20 , wherein the slot contains water swellable material.
31. The optical cable according to claim 20 , wherein an adhesive layer is interposed between the core and the sheath and wherein the adhesive layer does not comprise a tape.
32. The optical cable according to claim 20 , comprising an additional longitudinally extended reinforcing structure.
33. The optical cable according to claim 20 , wherein the indicium is a colored line.
34. A method of manufacturing an optical cable, comprising:
providing a load bearing core comprising a longitudinally and radially extending slot configured for housing an optical fibre, wherein the slot has an opening and a width ranging from about 1.1 to 1.5 times a diameter of the at least one optical fibre thereby providing a low clearance for the optical fibre housed therein and preventing the optical fibre being stuck to a second optical fibre when present, and wherein the slot has a depth equal to or less than a radius of the core, and wherein the core has a diameter of 3 mm at most;
housing the optical fibre in the slot;
winding the cable onto a coil while orienting the opening of the slot radially outwardly with respect to the coil;
applying a sheath over the core before winding the cable onto the coil; and
providing an indicium of the position of the slot in the core, wherein the indicium is a flattened longitudinally extended area of an outer surface of the sheath in correspondence with the slot longitudinal extension.
35. The method according to claim 34 , wherein the sheath is applied by extrusion.
36. The method according to claim 34 , further comprising the step of providing a water swellable material in the slot.
37. The method according to claim 34 , comprising the step of providing an adhesive layer interposed between the core and the sheath and wherein said adhesive layer does not comprise a tape.