Optical cable having a plurality of light waveguides arranged in a prescribed structure and having different mechanical sensitivies

• US 5,608,832 A
• Filed: 09/18/1995
• Issued: 03/04/1997
• Est. Priority Date: 04/14/1993
• Status: Expired due to Term

• Current Assignee: CCS Technology Inc. (Corning Incorporated)
• Original Assignee: Siemens AG
• Inventors: Opel, Ernst, Unger, Clemens, Pfandl, Walter, Schneider, Reiner, Stoecklein, Waldemar
• Primary Examiner(s): Bovernick, Rodney B.
• Assistant Examiner(s): Sanghavi, Hemang
• Application Number:
  US08/529,910
• Time in Patent Office: 533 Days
• Field of Search: 385/110, 385/111, 385/112, 385/113, 385/114, 385/127, 385/126, 385/109, 385/106, 385/105
• US Class Current: 385/112
• 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 6/4403 with ribbon structure G02B6/4429, G02B6/4439, G02B6/4479 take precedence
• CPC Class Codes: G02B 6/4408 Groove structures in support members to decrease or harmonise transmission losses in ribbon cables
• CPC Class Codes: G02B 6/4411 Matrix structure

Abstract

An optical cable comprises a plurality of light waveguides which are arranged at least one group with a prescribed structure. The light waveguides will have different mechanical sensitivities, with the waveguides having a low mechanical sensitivity being in those regions of the structure which have elevated mechanical stressing occurring.

Claims

1. In an optical cable having a plurality of light waveguides being arranged in at least one group having a prescribed structure, the individual light waveguides within the prescribed structure being respectively exposed to different mechanical stresses, the improvements comprising light waveguides with different mechanical sensitivities being within the prescribed structure, light waveguides having a lower mechanical sensitivity being arranged in at least one region of the prescribed structure in which elevated mechanical stresses occur, and light waveguides having a higher mechanical sensitivity being arranged in at least one region of the prescribed structure in which lower mechanical stresses occur.

2. In an optical cable according to claim 1, wherein the prescribed structure has a neutral axis and the light waveguides having the lower mechanical sensitivity are arranged within the structure where the light waveguides have the greatest distance from the neutral axis.

3. In an optical cable according to claim 2, wherein light waveguides having a minimum distance from the neutral axis are fashioned as light waveguides having the higher mechanical sensitivity.

4. In an optical cable according to claim 1, wherein the prescribed structure has a cross section with connecting lines between outwardly disposed light waveguides which are disposed in corners of the prescribed structure, said outwardly disposed light waveguides having lower mechanical sensitivity than the light waveguides spaced inward therefrom.

5. In an optical cable according to claim 1, wherein the light waveguides with the lower mechanical sensitivity have a lower MAC value than the remaining light waveguides, wherein MAC is established by

6. In an optical cable according to claim 5, wherein the MAC values below 7.4 are selected for the light waveguides having lower mechanical sensitivity, wherein λ

=1300 nm.

7. In an optical cable according to claim 5, wherein the MAC value for the light waveguides having a higher mechanical sensitivity and the light waveguides having a lower mechanical sensitivity differs by at least 0.5.

8. In an optical cable according to claim 5, wherein the MAC value for the light waveguides having a higher mechanical sensitivity and the light waveguides having a lower mechanical sensitivity differs by at least 1.

9. In an optical cable according to claim 5, wherein all of the light waveguides of the prescribed structure have a MAC value below 7.4.

10. In an optical cable according to claim 5, wherein all of the waveguides of the prescribed structure have a MAC value below 7.0.

11. In an optical cable according to claim 1, wherein light waveguides within the prescribed structure which would experience an increase in attenuation beyond an allowable limit value due to the arrangement of the prescribed structure in a finished cable are replaced by light waveguides having a lower mechanical sensitivity.

12. In an optical cable according to claim 1, wherein the prescribed structure is arranged within a U-shaped chamber element which is stranded together with other U-shaped chamber elements.

13. In an optical cable according to claim 1, wherein the prescribed structure is accommodated within a chamber element that has substantially a trapezoidal cross section.

14. In an optical cable according to claim 1, which includes a profile member provided with chamber-like depressions extending the length thereof, said prescribed structure being arranged in said chamber-like depression respectively.

15. In an optical cable according to claim 1, wherein the prescribed structure is accommodated in a closed protective sheath to form a stranded element and in that a plurality of said stranded elements are stranded to form a cable core.

16. In an optical cable according to claim 1, wherein each of the waveguides has a primary coating, and each light waveguide in the region of the elevated mechanical stresses has a primary coating with a greater layer thickness than the layer thickness of the primary coatings of the light waveguides in the region of lower mechanical stresses.

17. In an optical cable according to claim 16, wherein each light waveguide in the region of elevated mechanical stresses has a primary coating with a layer thickness that is greater than 1.5 through 4 times the layer thickness of the primary coating of the light waveguides in the regions of lower mechanical stresses.

18. In an optical cable according to claim 16, wherein each light waveguide in the region of the elevated mechanical stresses has a primary coating with a layer thickness that is two through three times the thickness of the primary coatings of the light waveguides in the region of lower mechanical stresses.

19. In an optical cable according to claim 16, wherein the primary coating of each light waveguide in the region of elevated mechanical stresses has a layer thickness between 0.02 and 0.05 mm.

20. In an optical cable according to claim 19, wherein the layer thickness of the primary coating of the light waveguide in the region of elevated mechanical stresses has a thickness between 0.03 and 0.04 mm.

21. In an optical cable according to claim 1, wherein each light waveguide has a primary coating with a primary coating of each light waveguide in the region of elevated mechanical stresses being of a softer material than the primary coatings of the light waveguides in the region of lower mechanical stresses.

22. In an optical cable according to claim 21, wherein the primary coating of each light waveguide in the region of elevated mechanical stresses is one to five times softer than the primary coatings of the light waveguides in the region of lower mechanical stresses.

23. In an optical cable according to claim 22, wherein the primary coating of each light waveguide in the region of elevated mechanical stresses is 1 to 2.5 times softer than the primary coatings of the light waveguides in the region of lower mechanical stresses.

24. In an optical cable according to claim 21, wherein the primary coating of each light waveguide in the region of elevated mechanical stresses has a primary coating of urethane acrylate having a modulus of elasticity between 0.5 and 2.5 MPa.

25. In an optical cable according to claim 1, wherein the light waveguides in the prescribed structure are arranged as a waveguide ribbon, wherein a light waveguide lying adjacent an outside edge of the waveguide ribbon have a lower mechanical sensitivity than the light waveguides lying farther toward an inside of the waveguide ribbon.

26. In an optical cable according to claim 25, wherein a plurality of waveguide ribbons are combined to form a stack of ribbons to form the prescribed structure.

27. In an optical cable according to claim 25, wherein the waveguide ribbon is formed by a standard ribbon with light waveguides having substantially the same mechanical sensitivity, and at least one light waveguide having a lower mechanical sensitivity being secured at an edge of the standard ribbon and aligned with the waveguides of said standard ribbon.

28. In an optical cable according to claim 25, wherein the waveguide ribbon has a row of light waveguides with the outer light waveguides having a lower mechanical sensitivity than the remaining light waveguides of the waveguide ribbon.

29. In an optical cable according to claim 25, wherein the light waveguides having the lower mechanical sensitivity occupy an outer edge of the waveguide ribbon and terminate an outer sheath thereof.

30. In an optical cable according to claim 25, wherein the waveguide ribbon has the light waveguides having the higher mechanical sensitivity disposed in the waveguide ribbon and has the waveguide with the lower mechanical sensitivity on each edge of the waveguide ribbon, all of said waveguides being embedded in an outside sheath of the waveguide ribbon.

31. In an optical cable according to claim 25, wherein the waveguide ribbons has an additional protective layer surrounding the waveguide ribbon.

32. In an waveguide cable according to claim 26, wherein each of the optical ribbons has an identical structure with light waveguides having a higher sensitivity being disposed in the interior of the waveguide ribbon and the outer edges of each waveguide ribbon having at least one light waveguide with a lower mechanical sensitivity.

33. In an optical cable according to claim 26, wherein an uppermost and lowermost ribbon of the stack of ribbons have interior light waveguides of a higher mechanical sensitivity and at least one outer light waveguide being of a lower mechanical sensitivity.

34. In an optical cable having a plurality of light waveguides being arranged in a prescribed structure having at least one region being exposed to elevated mechanical stresses and at least one second region being exposed to lower mechanical stresses than the one region, the improvements comprising the light waveguide of the prescribed structure being in at least two groups having different mechanical sensitivities with one group having a lower mechanical sensitivity than the other group of the two groups being arranged in the one region and the other group being arranged in the second region.

35. An optical cable comprising a plurality of light waveguides being arranged in at least one group having a prescribed structure with a neutral axis, the individual light waveguides within said prescribed structure being respectively exposed to different mechanical stresses with light waveguides in at least one outside region having a greater distance from the neutral axis being exposed to higher mechanical stresses than light waveguides in at least one inside region adjacent the neutral axis, the plurality of light waveguides being formed by light waveguides having different mechanical sensitivities with light waveguides having a lower mechanical sensitivity than the other light waveguides being arranged in the outside region of the prescribed structure and with the other waveguides with a higher mechanical sensitivity being disposed in the inside region adjacent the neutral axis of the prescribed structure so that elevated stresses applied to the light waveguides in the outside region will not create an excessive increase in attenuation.