Optical fiber/metallic conductor composite cable

• US 5,268,971 A
• Filed: 11/07/1991
• Issued: 12/07/1993
• Est. Priority Date: 11/07/1991
• Status: Expired due to Fees

• Current Assignee: Alcatel SA (Nokia Corporation)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Oberschlake, Timothy A., Nilsson, Richard C.
• Primary Examiner(s): Lee, John D.
• Assistant Examiner(s): PALMER, PHAN T H
• Application Number:
  US07/788,846
• Time in Patent Office: 761 Days
• Field of Search: 385/101, 385/100, 385/102, 385/103, 385/104, 385/105, 385/106, 385/107, 385/75
• US Class Current: 385/101
• CPC Class Codes: G02B 6/4407 with internal fluted support member G02B6/4429, G02B6/4439, G02B6/4479 take precedence
• CPC Class Codes: G02B 6/4416 Heterogeneous cables
• CPC Class Codes: H01B 11/22 Cables including at least one electrical conductor together with optical fibres

Abstract

The optical fiber/metallic conductor composite cable has a cable core with an optical fiber subgroup and an insulated metallic conductor subgroup. The optical fiber subgroup can be a loose tube construction, a slotted core construction, a unitube/monotube construction or a tight buffer tube construction. The individual insulated wires of the insulated metallic conductor subgroup extend longitudinally within the composite cable. Preferably, the optical fiber subgroup is on the outer periphery of the cable core to provide easy accessibility, but it can be centrally located.

Claims

1. A composite cable for transmitting both electrical signal transmissions and fiber optic signal transmissions comprised of:

a cable core having an optical fiber subgroup for the fiber optic signal transmissions and at least one metallic conductor subgroup for the electrical signal transmissions, said core having a generally circular cross-section;

said optical fiber subgroup having a plurality of optical fibers therein for conducting the fiber optic transmissions, said plurality of optical fibers being bundled together to form said subgroup, said optical fiber subgroup being separate and distinct from said metallic conductor subgroup but being bundled therewith, said optical fiber subgroup has a plurality of gel filled buffer tubes stranded around a central strength member, each gel filled buffer tube contains at least one of said plurality of optical fibers, said buffer tubes and strength member being held in place relative to one another by a binding material which excludes said metallic conductor subgroup from said optical fiber subgroup;

said at least one metallic subgroup having individually insulated metallic conductors for the electrical signal transmissions;

a water blockable filling compound impregnating said cable core; and

a plastic jacket which encapsulates said cable core.

2. A cable as described in claim 1 wherein said optical fiber subgroup extends along an outer periphery of said cable core.

3. A cable as described in claim 2 wherein said optical fiber subgroup runs parallel to a longitudinal axis of said cable.

4. A cable as described in claim 2 wherein said optical fiber subgroup follows a helical path along said outer periphery.

5. A cable as described in claim 1 wherein said optical fiber subgroup is centrally located in said cable and follows a longitudinal axis of said cable.

6. A cable as described in claim 1 wherein said optical fiber subgroup is provided with a stress-free operating window (SW) which substantially satisfies the equation:

space="preserve" listing-type="equation">SW(%)=(((BL .sup.2 +(π

*D1).sup.2)/(BL .sup.2 +(π

*D2).sup.2)).sup. 0.5 )-1) *100

Where;

BL=Effective buffer tube laylength

D1=(OD_cm)+(OD_bt *2)-(WALL*2)-(OD_fb)

D2=(OD_cm)+(WALL*2)+(OD_fb)

OD_bt =Buffer tube outer diameter

OD_cm =Central member outer diameter

WALL=Buffer tube wall thickness

OD_fb =Fiber bundle diameter

7. A cable as described in claim 6 wherein a minimum for the stress-free operating window (SW) is calculated by adding the amount of cable contraction (CC) and cable tensile elongation (CE) together where:

space="preserve" listing-type="equation">CC(%)=T*α

eff*100

and

space="preserve" listing-type="equation">α

eff=(Σ

AEα

)/(Σ

AE)

where;

T=Temperature change

α

eff=Effective thermal expansion coefficient

A=Cross-sectional area

E=Elastic modulus temp. extreme

α

=Thermal expansion coefficient

and

space="preserve" listing-type="equation">CE(%)=F/(Eeff*Σ

A)*100

and

space="preserve" listing-type="equation">Eeff=(Σ

AE)/(Σ

A)

where;

F=Cable tensile rating

Eeff=Effective elastic modulus

8. A cable as described in claim 1 wherein a metallic shield is disposed between said cable core and said jacket.

9. A cable as described in claim 8 wherein said metallic shield is corrugated.

10. A cable as described in claim 9 wherein a water blockable flooding compound is disposed between said metallic shield and said jacket.

11. A cable as described in claim 8 wherein said metallic shield is a longitudinally applied aluminum protective coating with a steel armor longitudinally applied therearound.

12. A cable as described in claim 1 further including a ripcord longitudinally disposed under said plastic jacket.

13. A composite cable for transmitting both electrical signal transmissions and fiber optic signal transmissions comprised of:

a cable core having an optical subgroup for the fiber optic signal transmissions and at least one metallic conductor subgroup for the electrical signal transmissions, said core having a generally circular cross-section;

said optical fiber subgroup having a plurality of optical fibers therein for conducting the fiber optic transmissions, said plurality of optical fibers being bundled together to form said subgroup, said optical fiber subgroup being separate and distinct from said metallic conductor subgroup but being bundled therewith, said optical fiber subgroup has a core body with a plurality of helical channels therein, said core body having a strength member centrally located therein, each channel is gel filled and contains at least one of said plurality of optical fibers, said optical fibers being held in said channels by a binder material;

said at least one metallic subgroup having individually insulated metallic conductors for the electrical signal transmissions;

a water blockable filling compound impregnating said cable core; and

a plastic jacket with encapsulates said cable core.

14. A cable as described in claim 13 wherein said optical fiber subgroup extends along an outer periphery of said cable core.

15. A cable as described in claim 14 wherein said optical fiber subgroup runs parallel to a longitudinal axis of said cable.

16. A cable as described in claim 14 wherein said optical fiber subgroup follows a helical path along said outer periphery.

17. A cable as described in claim 13 wherein said optical fiber subgroup is centrally located in said cable and follows a longitudinal axis of said cable.

18. A cable as described in claim 13 wherein said optical fiber subgroup is provided with a stress-free operating window (SW) which substantially satisfies the equation:

space="preserve" listing-type="equation">SW(%)=(((BL .sup.2 +(π

*D1).sup.2)/(BL .sup.2 +(π

*D2).sup.2)).sup. 0.5 )-1) *100

where;

BL=effective channel laylength

D1=(OD_cb)-(OD_fb)

D2=(OD_cb)-2x(CD)+(OD_fb)

OD_cb =core body outer diameter

CD=channel depth

OD_fb =fiber bundle diameter.

19. A cable as described in claim 18 wherein a minimum for the stress-free operating window (SW) is calculated by adding the amount of cable contraction (CC) and cable tensile elongation (CE) together where:

space="preserve" listing-type="equation">CC(%)=T*α

eff*100

and

space="preserve" listing-type="equation">α

eff=(Σ

AEα

)/(Σ

AE)

where;

T=temperature change

α

eff=effective thermal expansion coefficient

A=cross-sectional area

E=elastic modulus temp. extreme

α

=thermal expansion coefficient and

space="preserve" listing-type="equation">CE(%)=F/(Eeff*Σ

A)*100

and

space="preserve" listing-type="equation">Eeff=(Σ

AE)/(Σ

A)

where;

F=cable tensile rating

Eeff=effective elastic modulus.

20. A cable as described in claim 13 wherein a metallic shield is disposed between said cable core and said jacket.

21. A cable as described in claim 20 wherein said metallic shield is corrugated.

22. A cable as described in claim 21 wherein a water blockable flooding compound is disposed between said metallic shield and said jacket.

23. A cable as described in claim 20 wherein said metallic shield is a longitudinally applied aluminum protective coating with a steel armor longitudinally applied therearound.

24. A cable as described in claim 13 further including a ripcord longitudinally disposed under said plastic jacket.

25. A composite cable for transmitting both electrical signal transmissions and fiber optic signal transmissions comprised of:

a cable core having an optical fiber subgroup for the fiber optical signal transmissions and at least one metallic conductor subgroup for the electrical signal transmissions, said core having a generally circular cross-section;

said optical fiber subgroup having a plurality of optical fibers therein for conducting the fiber optic transmissions, said plurality of optical fibers being bundled together to form said subgroup, said optical fiber subgroup being separate and distinct from said metallic conductor subgroup but being bundled therewith, said optical fiber subgroup has a single gel filled oversized buffer tube having said plurality of optical fibers therein, said fibers are provided with an overlength to maintain a virtual stress-free condition during cable expansion;

said at least one metallic subgroup having individually insulated metallic conductors for the electrical signal transmissions, at least some of said individually insulated metallic conductors being adjacent to and in contact with said single gel filled oversized buffer tube of said optical fiber subgroup;

a water blockable filling compound impregnating said cable core; and

a plastic jacket which encapsulates said cable core.

26. A cable as described in claim 25 wherein said optical fiber subgroup extends along an outer periphery of said cable core.

27. A cable as described in claim 26 wherein said optical fiber subgroup runs parallel to a longitudinal axis of said cable.

28. A cable as described in claim 26 wherein said optical fiber subgroup follows a helical path along said outer periphery.

29. A cable as described in claim 25 wherein said optical fiber subgroup is centrally located in said cable and follows a longitudinal axis of said cable.

30. A cable as described in claim 25 wherein said overlength of said optical fiber is in a range of 0.1% to 0.2% of cable tensile elongation.

31. A cable as described in claim 25 wherein a metallic shield is disposed between said cable core and said jacket.

32. A cable as described in claim 31 wherein said metallic shield is corrugated.

33. A cable as described in claim 32 wherein a water blockable flooding compound is disposed between said metallic shield and said jacket.

34. A cable as described in claim 31 wherein said metallic shield is a longitudinally applied aluminum protective coating with a steel armor longitudinally applied therearound.

35. A cable as described in claim 25 further including a ripcord longitudinally disposed under said plastic jacket.

36. A composite cable for transmitting both electrical signal transmissions and fiber optical signal transmissions comprised of:

a cable core having an optical fiber subgroup for the fiber optic signal transmission and at least one metallic conductor subgroup for the electrical signal transmissions, said core having a generally circular cross-section;

said optical fiber subgroup having a plurality of optical fibers therein for conducting the fiber optic transmission, said plurality of optical fibers being bundled together to form said subgroup, said optical fiber subgroup being separate and distinct from said metallic conductor subgroup but being bundled therewith, each optical fiber of said optical fiber subgroup has at least one encapsulating layer to form a tight buffer tube thereon in direct contact with its respective optical fiber so that there is no fiber overlength;

said at least one metallic subgroup having individually insulated metallic conductors for the electrical signal transmissions;

a water blockable filling compound impregnating said cable core; and

a plastic jacket which encapsulates said cable core.

37. A cable as described in claim 36 wherein said optical fiber subgroup extends along an outer periphery of said cable core.

38. A cable as described in claim 37 wherein said optical fiber subgroup runs parallel to a longitudinal axis of said cable.

39. A cable as described in claim 37 wherein said optical fiber subgroup follows a helical path along said outer periphery.

40. A cable as described in claim 36 wherein a metallic shield is disposed between said cable core and said jacket.

41. A cable as described in claim 40 wherein said metallic shield is corrugated.

42. A cable as described in claim 41 wherein a water blockable flooding compound is disposed between said metallic shield and said jacket.

43. A cable as described in claim 40 wherein said metallic shield is a longitudinally applied aluminum protective coating with a steel armor longitudinally applied therearound.

44. A cable as described in claim 36 further including a ripcord longitudinally disposed under said plastic jacket.