JPS5913204A - Construction for mooring optical fiber unit in optical submarine repeater - Google Patents

Abstract

PURPOSE:To prevent the pulling-in of an optical fiber unit into an optical submarine cable by connecting the other end of the tail cable passed with the optical fiber unit from the optical submarine cable without unraveling the same to a feed-through part. CONSTITUTION:A tail cable (designated as a metallic pipe) has a straight part 14, a spiral part 15, etc. The tensile body of an optical submarine cable is detained with an anchor 12, and after metallic pipes 14-16 are passed onto the optical fiber unit, the cable side of the pipe 14 is stuck to the anchor 12, then an insulator 18 is molded. A pipe 14 is passed into a gimbal 13 and a bellows 20, and a pipe 15 is formed spiral and the forward end thereof is connected to the feed-through part 17 of the repeater, by which the optical fiber unit is introduced into the repeater 21 without unraveling. The inside diameter of the pipes 14-16 of the tail cable is larger by about 20% than the outside diameter of the optical fiber unit, and the curvature of the rise 16 in the spiral part is better as it is higher.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for retaining a T-fiber unit in an optical submarine cable coupling.

In the long-distance optical submarine RM cable system using an optical submarine cable, an optical submarine repeater is connected every several tens of kilometers to reproduce the signal. It is mechanically and electrically connected to the fiber optic submarine cable cable attached to the MM end of the cable. Optical fiber cables used in optical submarine cables,
In the optical submarine cable 11, several or more optical fibers 11 are twisted around the tensile strength member (hereinafter referred to as ``fino ζ corner'', 1 and t+t1- )
will be accommodated in A crab on the optical submarine cable ('[
J+1, and as the optical submarine cable extends, the optical fiber cable housed inside also extends.

The elongation of this optical fiber and the cable (1
If the people are not equal, D of the original Wlj low-capacity
'A shift occurs between the two at the end of M, and the alternate optical fibers are drawn into the optical submarine cable.

The optical submarine repeater enclosure has a feedthrough portion to which the optical fiber is fixed at the enclosure end I in order to introduce the optical fiber into the enclosure.

Therefore, if the optical fiber unit is pulled in,
The coating of nylon or the like is removed from the optical fiber at the feedthrough portion, and there is a risk that the optical fiber may break near the feedthrough portion even under slight tension.

In order to solve these problems, the present invention has developed an optical fiber unit from an optical submarine cable, without unraveling it, into a spiral metal pipe called a tail cable, which has an inner diameter slightly larger than the outer diameter of the unit. An optical fiber unit of an optical submarine repeater, in which the entire optical fiber unit is held back by connecting the other end of the tail cable to the feedthrough part, thereby preventing the optical fiber unit from being drawn into the optical submarine cable. It provides a retaining structure.

The present invention will be described in detail below with reference to the drawings.

FIG. 1.2 is an example of an optical submarine cable' and an optical fiber unit for explaining the present invention. 1 is an optical fiber unit, 2 is a three-part pipe, 3 is a tensile strength member, 4 is a metal tube, 5 is an insulator, 6 is an external jacket, 7 is a central tensile strength member, 8 is an optical fiber core wire, and 9 is a buffer material. be. In this cable structure example, after the cable is manufactured, the original fiber unit 1 receives a very slight uniform side pressure from the surroundings from the three-part pipe 2, and when an attempt is made to pull out the optical fiber unit 1 from the cable, an amount equivalent to a frictional force is generated. Requires pulling force. This frictional force is small for a cable unit length, but when it reaches a length of several tens of kilometers like an optical submarine cable, it becomes a considerably large force, and therefore the cable elongation and the optical fiber unit elongation 1) becomes equal. That is, since there is an infinitely long cable on both sides at each cable point, there is no deviation between the optical submarine cable and the optical fiber unit.

However, in optical submarine cable coupling, the condition that an infinitely long cable exists on the repeater side does not hold, so the optical fiber in the feedthrough section
Considerable tension is applied, which is undesirable.

For this reason, the present invention provides an all-island pipe having an inner diameter slightly larger than the outer diameter of the optical fiber unit, which is located between the optical submarine cable coupling and the optical submarine repeater, and which is continuously led out from the optical submarine cable coupling. After penetrating the cable, it is formed into a spiral shape, and the frictional force between the outer surface of the optical fiber unit and the inner wall of the metal pipe within this forming part prevents the optical fiber unit from being drawn into the cable in stages.

FIG. 3 is for explaining the present invention, and 10 is an optical submarine cable, 11 is a boot, 12 is an anchor that holds the tensile strength member 3 of the optical submarine cable, 13 is a gimbal forming a universal joint, and 14 is a tail. Although a partially cross-sectional interior is shown as a straight section of a metal pipe called a cable, it is actually fixed to the anchor 12. 5 is the spiral part of the tail cable, 16 is the part where the tail cable begins to form into a spiral shape, 17 is the feedthrough part of the optical submarine repeater body, 18 is the insulator, 19 is the anchor housing, and 20 is the rubber bellows. , 21 is a part of the optical submarine repeater body.

The creation of the retaining structure for the optical fiber unit of the present invention will be explained. First, the tensile strength member of the optical submarine cable is held in place by the anchor 12, and then the metal pipes (14, 15, 1
6), the cable side of the metal pipe (14) is fixed to the anchor 12, and this part is molded with an insulator 18.
Insulate from seawater. Next, gimbal 13. After passing the straight part 14 of the tail cable through the rubber bellows 20 etc.,
By forming the metal pipe (15) into a spiral shape from the part 6 and connecting the tip to the feedthrough part 17, the original fiber unit can be prevented from coming apart.
It is introduced into the interior of the optical submarine repeater body 21. In addition,
The relationship between the outer diameter of the optical fiber unit and the inner diameter of the pipe is selected such that the optical fiber unit can only be inserted into a straight section of the pipe.

The inner diameter of the metal pipes (14, 15, 16) of the tail cable is at most 20% larger than the outer diameter of the optical fiber unit, and the curvature of the twisted and forming rising portion 16 should also be as large as possible for better transmission. Desirable in terms of characteristics.

Figures (1) and (2) show the relationship between the tension applied to the optical fiber unit and the length of the optical fiber unit drawn into the tail cable when the number of turns in the tail cable is 1 and 3, respectively. It is a characteristic.

Figure 5 shows an outline of the experiment. The tail cable 22 is fixed by a vise 23, and tension is applied to the optical fiber unit 1 in the direction of the arrow. According to FIG. 4, it is understood that even if the number of turns of the tail cable is one, the retraction length at a tension of 35 kg is as small as 2U, and when there are three turns, there is no retraction at all.

Furthermore, when we investigated the change in optical loss while retaining the optical fiber unit and applying tension to the optical submarine cable according to the present invention, we found that even at tensions exceeding 30 kg,
In other words, the anchoring structure of the optical fiber unit according to the present invention has a simple structure, is economical, and has good characteristics.
This provides a retaining structure for an optical fiber unit in a pull.

Note that parts 14 and 15 are described as metal pipes.

The pipe 16 does not necessarily have to be a metal pipe, but may be a pipe made of other materials such as a composite material such as reinforced plastic as long as the desired frictional force can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of an optical submarine cable to which the present invention is applied, FIG. 2 is a cross-sectional view showing an example of the structure of an optical fiber unit to which the present invention is applied, and FIG. 3 is a cross-sectional view showing an example of the structure of an optical fiber unit to which the present invention is applied. A vertical cross-sectional view showing the structure of the optical submarine cable coupling shown in FIG.
FIG. 4 is a characteristic diagram for explaining the present invention in detail, and FIG. 5 is a schematic diagram of an experimental example for explaining the present invention in detail. 1... Optical fiber unit, 2... 3-split pipe,
3... Tensile strength wire, 4... Metal cube, 5
...Insulator, 6.Outer jacket, 7.
...Central tensile strength body, 8...Optical fiber core wire,
9... Cushioning material, 10... Optical submarine cable, 11...
・Boots, 12... Anchor, 13... Jimba/u%
14... Straight metal pipe part of the tail cable, 15... Viral part of the tail cable metal pipe, 16... Part where the metal pipe of the tail cable begins to be formed into a spiral shape, 17... Feed through part , 18... Insulator, 19... Anchor housing, 20... Rubber bellows, 21... Optical submarine repeater body, 22... Tail cable, 23...
·vise. Patent applicant: International Telegraph and Telephone Co., Ltd. agent: Daibu: 1 person from outside the university

Claims (1)

[Claims] An optical cable comprising a cable force and a pulling part for introducing a fiber unit of an optical submarine cable into an optical submarine repeater, and a feedthrough part for introducing an optical fiber of the fiber unit into the interior of the optical submarine repeater body. In the optical fiber unit retaining structure of a submarine repeater, the optical fiber unit is provided with a spiral pipe which is penetrated in a state of close contact and whose both ends are fixed to the feedthrough part and the AiJ cable coupling part, When tension is applied between the submarine cable and the Ail cable coupling, the amount by which the Mfl optical fiber unit is drawn into the optical submarine cable is determined by the frictional force acting between the fiber optic unit 71 and the spiral pipe. The optical submarine repeater is characterized in that the feedthrough portion is configured such that the feedthrough portion is reduced to a negligible extent by deflection.
Uni,) retaining structure.