Connection joining the ends of two under-water optical fiber cables and a method of manufacturing same

A connection for joining the ends of two under-water optical fiber cables each comprising: an optical core constituted by a carrier wire covered by a helically grooved plastics rod with optical fibers inserted in its grooves; a protective tape surrounding the optical core; a steel wire arch assembly; a copper tube drawn down over the arch assembly; and a plastics insulating sheath. Said connection includes two smooth rods (22, 22') glued to the ends of each cable on the carrier wire (2, 2') round which the optical fibers (4, 4') are wound, the fibers being welded one-to-one and protected by tapes (23, 23'), two split tubes (24, 24') covering the optical fibers wrapped in tape at the ends of each cable, a sheath (19) around which the ends of each arch assembly are formed again into cables and a sleeve (12) glued and/or crimped on the ends of each arch assembly.

The present invention relates to a connection joining the ends of two 
under-water optical fiber cables, each cable comprising an optical core 
constituted by a carrier wire covered by a helically grooved plastics rod 
having optical fibers received in its the grooves; a protective tape 
surrounding the optical core; a steel wire arch assembly; and an 
insulating sheath made of a thermoplastic substance. 
It also relates to a method of manufacturing such a connection. 
BACKGROUND OF THE INVENTION 
The Applicant's French Patent application No. 81 24 514 describes various 
connections for joining two cable ends to repair a damaged cable. These 
connections are formed by connection boxes which take up an appreciable 
volume and with an outside diameter of about 150 mm and a length of about 
1.30 m. 
Further, said connection box is completely rigid. This makes it less easy 
for the box to pass a davit when winding said cable. These boxes can be 
used only for such repairs as may be necessary after complete manufacture 
of the cable. 
Preferred embodiments of the present invention remedy such drawbacks, by 
providing a connection and a method of connecting which allows a cable to 
be repaired during its various manufacturing steps. Repairs are made after 
insulation with a first thermoplastic insulating sheath. 
Further, such preferred embodiments allow a connection to be made which 
maintains the geometric and dimensional appearance of the cable without 
increasing its rigidity, thus making it easier for the repaired cable to 
pass on a davit. 
SUMMARY OF THE INVENTION 
The present invention provides a connection joining the ends of two 
under-water optical fiber cables, each cable comprising an optical core 
constituted by a carrier wire covered by a helically grooved plastics rod 
having optical fibers received in its grooves; a protective tape 
surrounding the optical core; a steel wire arch assembly; and an 
insulating sheath made of a thermoplastic substance; wherein the 
connection includes: 
a. two plastics rods glued at the ends of each cable to the carrier wire 
around which the ends of optical fibers are wound, said rods being welded 
individually to each other and being protected by two tapes; 
b. two split plastics tubes covering the optical fibers which are 
surrounded with tape at the ends of each cable; 
c. a sheath around which the ends of each arch assembly are reconstituted; 
and 
d. a sleeve glued and/or crimped onto the ends of each arch assembly. 
Advantageously, the space left free between the ends of each arch assembly, 
the sheath and the sleeve as well as the ends of the sleeve are filled 
with glue. 
In the method of manufacturing a connection according to the invention: 
a. the insulating sheath and the drawn down copper tube are removed from 
each cable end along a length very much greater than that required for 
said connection, the arch assembly is untwisted and the grooved rod is 
removed from each cable end along a length very much greater than that 
required for said connection, leaving the optical fibers and the carrier 
wire stripped; 
b. the sheath and the sleeve are engaged on a cable end; 
c. the two smooth rods are placed on the cable ends; 
d. the optical fibers are welded together one-to-one and they are wound 
round the smooth rods on either side of their welds; 
e. the resilient protective tapes are set in position on the fibers and 
then the split tubes are set in position on the tapes; 
f. the sheath is brought back to the center of the connection, covering 
each end of the split tube, then each arch assembly is reformed over the 
sheath, and 
g. the sleeve is brought back to the center of the connection on the end of 
each arch assembly. 
Preferably, the space left free between the ends of each arch assembly, the 
sheath and the sleeve as well as the ends of the sleeve is filled with 
glue.

MORE DETAILED DESCRIPTION 
In FIGS. 1A and 1B, the end of each cable has an optical core 1, 1' 
constituted by a carrier wire 2, 2' covered by a helically grooved rod 3, 
3' made of a plastics material in which optical fibers 4, 4' are received. 
Said optical core is covered by a protective tape 5, 5' then by an arch 
assembly 6, 6' made of steel wires and consisting of a first arch 6, 6'A 
and of a second arch 6B, 6'B. The ends of the wires are held clamped 
against the optical core by two regions of whipping or binding 7A, 7'A and 
7B, 7'B to prevent said arch assembly from becoming untwisted and coming 
apart before the ends are connected together. A copper tube 8, 8' is drawn 
on the arch assembly and is covered by an insulating sheath 9, 9'. In the 
above embodiment, the cable has a return conductor 10, 10' covered with a 
protective sheath 11, 11'. 
In FIG. 2, which shows the end of one of the cables, the arch assembly 6 is 
enclosed in a sleeve 12. The copper tube 8 drawn down on the arch is 
reconstituted by a copper tape 13 longitudinally welded at 14. 
A thermoplastic moulding 15 connects the insulating sheath 9 of said cable 
end and the insulating sheath of the end of the other cable, not shown. In 
the above form of embodiment which includes a return conductor, a metal 
braiding 16 connects the return conductor 10 of said cable end and the 
conductor of the end of the other cable, not shown, and a heat-shrinkable 
sleeve 17 connects the protective sheath 11 of said cable end and the 
protective sheath of the end of the other cable, not shown. 
FIG. 3 shows the inside of the sleeve 12 and the various reconstituted 
layers. In said figure, the optical fibres 4, 4' are connected by welding 
and protected by individual sleeves 21. 
The fibers 4 are wound round smooth rod 22 which is itself glued to the 
carrier wire 2 and they are protected by a tape 23 equivalent to the tape 
5 of FIG. 1A. A split tube 24 covers the tape 23. 
The same applies to the fibers 4' wound round a smooth rod 22' which is 
itself glued to the carrier wire 2' and protected by a tape 23' equivalent 
to the tape 23. A split tube 24' covers the tape 23'. 
Both ends of each split tube 24, 24' are covered by sheaths 19. The ends of 
the arch assemblies are wound onto said sheath to reconstitute a cable. 
The sleeve 12 covers the ends of the arch assemblies and is filled with 
glue 20. Two longitudinally welded copper tapes 13, 13' on each side of 
the sleeve reconstitute the copper tubes 8, 8' drawn down over each cable 
end. A reconstitution moulding 15 made of a thermoplastic substance 
ensures the continuity of the insulating sheaths 9, 9' of each cable end. 
In said form of embodiment a longitudinally welded conductive metal tape 
16 provides continuity of the return conductor 10, 10' and a heat 
shrinkable sleeve 17 provides continuity of the protective sheath 11, 11' 
at each cable end. 
The connection described hereinabove is manufactured as follows: 
The protective sheath 11, the return conductor 10, the insulating sheath 9 
and the drawn down copper tube 8 are removed from each cable end along a 
length very much greater than that required for said connection. 
The arch assembly 6 is untwisted and the rod 3 is removed from each cable 
end along a length greater than that required for said connection, leaving 
the optical fibers 4 and the carrier wire 2 stripped. 
The sheath 19 and the sleeve 12 are engaged on a cable end. 
The two smooth rods 22, 22' are placed on the two carrier wires 2, 2'. 
The optical fibers are welded together one-to-one and each weld is 
protected by an individual sleeve 21 and the fibers are wound round each 
smooth strength member on either side of their welds 
The resilient tapes 23, 23' are set in position on the fibers then the 
split tubes are set in position on the tapes. 
The sheath 19 is brought back to the centre of the connection, covering 
each end of the split tube, then each arch assembly is reformed over the 
sheath. 
The sleeve 12 is brought back to the centre of the connection on the end of 
each arch assembly. 
The space left free between the ends of each arch assembly, the sheath and 
the sleeve as well as the ends of the sleeve is filled with glue 20. 
The drawn down copper tube 8, 8' is reconstituted up to the level of the 
sleeve 12 by placing two copper tapes 13, 13' on either side thereof, said 
copper tapes being welded longitudinally by two welds 14, 14'. 
The continuity of the insulating sheath 9, 9' of each cable end is provided 
by a moulding 15 made of a thermoplastics substance along the whole length 
of the connection. 
In said form of embodiment, the continuity of the return conductor on each 
cable end is provided by a longitudinally welded conductive metal tape 16 
and the continuity of the protective sheath at each cable end is provided 
by a heat shrinkable sleeve 17. 
Of course, without going beyond the scope of the invention, metal braid 
could be used to reconstitute the return conductors. 
Also the invention can be applied to cables which do not have a return 
conductor, in which case the number of steps is reduced.