JPH031114A - Optical fiber cable core - Google Patents

Abstract

PURPOSE: To obtain a relatively lightweight core for which optical fibers are used by housing and installing the plural optical fibers into slots formed in the peripheral regions of strength member matrices. CONSTITUTION: The optical fiber cable consists of the metallic matrices 1, 2, 5 which act as primary longitudinal strength members and as a central solid conductor. The peripheral surface of a metallic tube 2 is provided with the several slots 3 extending in a longitudinal direction at equal angles equidistantly from the axial line of the cable. The respective slots 3 are provided with the plural fiber conductors 4 in the form of the fibers alone or the form of ribbons or the form of ribbon bundles. A packing compd. having waterproofness/heat resistance is packed into the remaining parts of the respective slots. As a result, the lightweight core for which the optical fibers are used is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates particularly, but not exclusively, to an optical fiber cable for submarine communications, and to a core for this cable.

[Problem of the Invention] An object of the present invention is to provide a relatively lightweight core using an optical fiber. The core can also act as the primary longitudinal strength member of the cable in which it is incorporated.

That is, the present invention comprises a matrix of longitudinal strength members made of metal, in which a plurality of optical fibers are accommodated in longitudinal slots spaced in a hermetically separated manner and equally spaced in the radial direction in the peripheral area of the matrix. It provides cores for optical fiber cables. This core serves as at least the primary longitudinal strength member of the cable, thereby allowing the cable to be considerably lighter.

Preferably, the core matrix comprises a metal core joined to a metallic tubular outer sheath, with a longitudinal recess in the surface of the core closed by the sheath to form a longitudinal slot.

Preferably, the metal core comprises a solid metal rope or loft, the outer surface of which is joined to an inner metal tube having a recessed outer surface. In addition, the inner tube and outer sheath are made of metal tape.

The metal core and the tubular sheath may be joined by any suitable processing method, such as co-extrusion, conforming, cold welding, resistance welding, torch welding, laser welding, or swaging.

Since the number of metal processing steps is kept to a minimum, the production of cables using the above-mentioned core takes less time than conventional methods.

Additionally, the cable's light weight and torque characteristics make it easy to manufacture and long-distance installation. This is especially true when using tension rope as core material. This is because there is no need to provide additional tension members (and therefore no limitations on manufacturing speed due to wire facilities or cutting) (i.e., high strength cables are saved and protection from abrasion, crushing and impact).

Furthermore, since the cable of the present invention is conductive, it can be used for power transmission and signal transmission, and there is no need to use a conductor in addition to the strength member. For this reason, the cable according to the invention can be constructed with a core provided with a non-metallic sheath as described above.

If a separate conductor is required for dedicated protection,
In the cable of the present invention, further electrical conductors can be embedded in the outer non-metallic sheath.

According to another embodiment of the invention, a matrix of longitudinal strength members made of metal is provided, in which a plurality of optical fibers are arranged in internally hermetically separated longitudinal slots arranged radially equally in the peripheral region of the matrix. installed and accommodated,
the matrix comprises a metal core, preferably rope;
A core for an optical fiber cable is provided, the peripheral region of which is comprised of a tubular layer of thermoplastic material, preferably a liquid crystal polymer. This tubular layer becomes the outermost layer of the strength member matrix, with slots provided throughout the interior of the tubular layer or at the interface between the tubular layer and the metal core. Alternatively, a tubular layer may be provided within the shedding matrix between the metal core and the outer tubular layer, with slots provided at the interface of the plastic tubular layer and the outer metal tubular layer.

[Description of preferred embodiments of the invention] Some examples of application of the invention will be explained with reference to the accompanying drawings.

1 to 6 are cross-sectional views showing some configurations of optical fiber cables that are embodiments of the present invention.

Referring first to FIG. 1, a fiber optic cable consists of a metal matrix 1, 2.5 which acts as a primary longitudinal strength member and as a solid metal conductor. The matrix consists of a metal crabbed steel rope l, but instead of this it is possible to use a rope made of metal crabbed steel wire, a metal crabbed wire itself, or a simple rope or wire, etc. A metal tube 2 is joined to the outer surface of this rope I. The metal tube 2 and the rope l can be joined by simultaneous extrusion, conforming, cold welding, resistance welding,
The welding may be performed firmly, continuously, or intermittently by torch welding, laser welding, or swage processing. If appropriate, the metal tube 2 can be constructed from a tape, for example by resistance welding or laser welding.

The circumferential surface of the metal tube 2 is provided with several longitudinally extending slots, twelve in this embodiment, at equal angles. These slots are at equal distances from the cable axis. In this embodiment, these average radii are approximately 3/4 of the cable core or matrix as a whole, but approximately 0.
7, or in the range of 0.6 to 0.8, or in the extreme range of 0.3 to 0.9. The slot 3 is uniform in contour and may be straight in the direction of the cable axis or helical or counterhelical (S-Z). The slot 3 may be formed during the formation of the metal tube, or may be formed later in a separate step.

Each slot 3 is provided with a plurality of fiber conductors 4 in the form of fiber sleeves or in the form of ribbons or ribbon bundles. The remaining portion of each slot is preferably filled with a suitable waterproof/temperature resistant filling compound, preferably a hydrogen scavenger.

Furthermore, the matrix I, 2.5 is a metal tube 5 joined to the surface of the inner metal tube 2 by any of the processing methods that could be used to join the inner tube 2 and the rope l.
It is equipped with A metal tube 5, preferably constructed of tape, closes off all the slots 3 and hermetically separates them from the outside.

The matrix I, 2.5 is protected by a non-metallic sheath 6.7 of plastic or rubber extrusion. This provides protection against mechanical wear and impact damage and acts as an electrical insulator. In this embodiment, the material of the outermost layer 7 is harder than the inner part of the exterior.

If a second conductor is required, the inner part 6 of the non-metallic sheath
A further tubular metal layer (not shown) is provided at the interface 9 between the outer part 7 and the outer part 7. This metal layer acts as a second power transmitter or as a dedicated protective screen or as protection from fish.

The entire non-metallic layer 6.7 can also be provided with an armor layer (not shown), as shown at 10, to increase its resistance to abrasion, crushing and impact.

It is advantageous to use the same metal for the inner tube 2 and outer tube 5 and for the optical cladding of the wire or rope l. High purity copper is preferred as this metal, but aluminum or other metals with suitable electrical and mechanical properties may also be used.

Note that by removing part or all of the outer metal tube 5, the optical fiber can be easily exposed and repaired or removed. For example, the portion of the tube 5 that overlaps one of the slots 3 can be trimmed off by conventional means.

In some cases it may be advantageous to replace some of the optical fiber conductors 4 in the slots 3 with conventional communication wires or with reinforcing or lightening fillers.

Next, referring to FIG. 2, the inner and outer tubes 2 and 5 are
At the same time, the optical fiber 4 is inserted into the slot 3.
to be introduced. This reduces the number of required steps and increases the potential strength of the cable.

A further embodiment is shown in FIG. In this embodiment, an optical fiber 4 is held in each slot 3 during manufacture by a spiral metal wire or tape 8 with circular ends. This wire or tape 8 can be installed in a spiral groove formed in the inner tube 2, and the central wire 1 and the inner tube 2 can be connected to each other.
It is firmly joined to the tube 2 by any of the methods described above.

The welding of the outer tube 5 to the inner tube 2 is facilitated by the presence of a clean intermediate layer of wire 8 made or clad of the same metal as the inner and outer tubes 2.5, for example copper or aluminum. Further, in this configuration, since there is an extra portion between the windings of the wire 8, an extra optical fiber 4 can be provided in each slot 3.

A further embodiment shown in FIG. 4 is substantially the same as in FIG. 3, except that an outer tube 5 is provided along the length of the cable, consisting of a metal tape butt-welded to a pair of strips 11 in diametrically opposed positions. are different. These metal tapes 5
and the strip 11 can be held during manufacture by a metal wire 8.

Furthermore, instead of the metal wire 8, a non-metallic filament-like member such as polymer yarn can also be used.

The cable shown in Figure 5 is a solid metal matrix I, 2
．． 5 is different from that in FIG. inner tube 2
is provided with longitudinal fins I2 projecting radially outwardly from its surface between each pair of adjacent slots 3. Instead of the outer tube 5, each slot 3 of the cable has a
A cylindrical longitudinally extending portion 13 is provided which is complementary to the channel formed between adjacent fins 12. These portions 13 are constructed of metal tape of appropriate width or shape.

This arrangement has the advantage that there is no need to provide an outer metal tube 5 and is therefore simple to manufacture.

In the embodiment shown in FIG. 6, the outer tube 5 consists of six equal parts, each part closing a corresponding one of only six slots 3 formed in the inner tube 2. In the embodiment shown in FIG.

The six slots 3 in the bar of the inner tube 2 do not accommodate tip fibers 4, but they are used to provide the section 5 with a radially inwardly projecting projection.

The part 5 can be composed of a U-shaped metal tape, and the inward projections or legs are adapted to fit into the slots 3. Instead of spanning three slots, each portion 5 may span four or more slots, if desired.

This arrangement has the advantage that there is no need to provide an outer tube 5 and therefore manufacturing is simplified. Furthermore, in some cases, the use of bonding tape or wire 8 may be dispensed with.

In the case of the matrix in the inner tube 2 and/or outer tube 5 of the configuration shown in FIGS. 1 to 6, instead of a metallic material, a thermoplastic material, preferably a liquid crystal polymer (LCP)
) can be used. In this case, slot 3 is L
It can be provided within the CP layer 2.5, or at the interface between the L CP layer 2 and the metal tube 5, or at the interface between the CP layer 5 and the metal core l,2.

Although the present invention has been described with reference to submarine communication cables, the present invention can also be used in applications other than submarine communication cables, such as as a power transmission body for composite cables.

[Brief explanation of drawings]

1 to 6 are cross-sectional views showing different embodiments of the optical fiber cable according to the present invention. 1, 2.5 is a metal matrix, 3 is a slot, 4 is a tip fiber conductor, 6.7 is a non-metallic sheath, 8 is a wire (tape), and 12 is a fin. Patent applicant: Telephone Cables Limited

Claims (1)

[Scope of Claims] (1) consisting of a matrix of longitudinal strength members made of metal, in which a plurality of optical fibers are accommodated in internally hermetically separated longitudinal slots equally spaced radially in the peripheral area of the matrix; Installed core for optical fiber cable. (2) A cable incorporating a core according to claim 1, wherein the core is at least a primary longitudinal strength member of the cable. 3. The core of claim 2, wherein said core is the only longitudinal strength member of the cable. (4) The core matrix comprises a metal core joined to a metallic tubular outer sheath, and wherein the core matrix has a longitudinal recess in the surface of the core, and the recess is closed by the sheath to form a longitudinal slot. The core described in item 1. (5) The core according to claim 4, wherein the metal core is constituted by a solid metal rope or rod, and the outer surface of the rope or rod is joined to an inner metal tube having a concave portion formed on the outer surface. (6) The core according to claim 5, wherein the inner tube and the outer sheath are made of metal tape. (7) consisting of a matrix of longitudinal strength members made of metal, in which a plurality of optical fibers are accommodated and installed in longitudinal slots spaced in a hermetically separated manner, provided equally in the radial direction in the peripheral area of the matrix; A core for an optical fiber cable, comprising a metal core and a peripheral region consisting of a tubular layer of thermoplastic material. (8) The core according to claim 7, wherein said tubular layer comprises a liquid crystal polymer. 9. The core of claim 7, wherein said tubular layer is the outermost layer of said strength member matrix, and wherein said slot is provided entirely within said tubular layer. 10. The core according to claim 7, wherein the tubular layer is the outermost layer of the strength member matrix, and the slot is provided at an interface between the tubular layer and the metal core. 11. The core according to claim 7, wherein the slot is provided at an interface between the plastic tubular layer and the outer metal tubular layer. (12) An optical fiber cable using the cable core according to any one of claims 1 to 7.