JP2007272098A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable which is excellent in economical efficiency, intermediate point post-branching characteristic, identification characteristic of coated optical fibers, and taking out characteristic of coated optical fibers, wherein the number of optical fibers is easily increased. <P>SOLUTION: The optical fiber cable is provided with: an inclusion 11, of which the cross section has a form of a cross, for example, having partition walls 11a radially extending from the center; a plurality of optical fiber ribbons 12 which are stacked and stored between the respective partition walls 11a of the inclusion 11; and a jacket 13 which integrally coats the inclusion 11 and the optical fiber ribbons 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical fiber cable that is used as a trunk cable of an optical communication network and the like and excellent in economic efficiency and intermediate post-branching.

  In recent years, with the rapid spread of the Internet and the like, construction of an optical communication network using a low-loss and broadband optical fiber has been promoted, and along with that, the outer cover is removed at the middle of the cable, the optical fiber is taken out, There is a growing need for so-called intermediate post-branch optical fiber cables that can connect desired optical fibers.

  As an optical fiber cable having such an intermediate rear branching property, a plurality of grooves (slots) 2 are conventionally provided on the outer periphery of the slot rod 1 as shown in FIG. A slot-type optical fiber cable is known in which a plurality of tape cores 3 are stacked and stored, a pressing tape 4 is wound around the outer periphery thereof, and a jacket 5 is further provided thereon. In FIG. 4, 6 and 7 indicate a tensile body and a tear string, respectively.

  Recently, as shown in FIG. 5, a plurality of optical fiber ribbons 3 are laminated, a buffer layer 8 is provided around them, and a jacket 9 is applied to the outside by extrusion of plastic such as polyethylene. The thing is developed (for example, refer patent document 1). Since this cable does not have a slot, it is generally called a slotless type optical fiber cable, and can be economically produced because it is simpler in structure and easier to manufacture than a slot type optical fiber cable. It has characteristics. In FIG. 5, reference numerals 61 and 71 denote strength members and tear strings embedded in the jacket 9.

  However, this slotless type optical fiber cable has a problem that it is difficult to increase the number of cores because it is less discernable than the slot type optical fiber cable. That is, in the slot type optical fiber cable as shown in FIG. 4, for example, by attaching the tracer mark 1a to the slot rod 1, it becomes possible to identify the slots. Therefore, if the optical fiber ribbon 3 can be identified for each slot, Therefore, it is easy to identify the optical fiber ribbon 3 even if the number of fibers is increased. On the other hand, in the slotless type optical fiber cable, it is necessary to be able to identify only with the optical fiber ribbon 1, and there is a limit to the number of fibers. Incidentally, conventionally, the optical fiber core wire 3 is identified by the color arrangement of the optical fiber core wire 3.

Further, when the number of fibers is increased, in the slotless optical fiber cable, since many optical fiber ribbons 3 are arranged in the center of the cable, it is difficult to take out the optical fiber ribbon 3 near the center. There was a problem.
JP 2001-42182 A

  As described above, the so-called slotless optical fiber cable has a feature that it can be economically produced because it has a simple structure and is easy to manufacture, compared with the slot type optical fiber cable, but it has a characteristic that the core can be distinguished. In addition, there was a problem that multi-centering was difficult due to poor take-out performance.

  The present invention has been made to meet the demands of the problems of the prior art, and is excellent in economic efficiency and intermediate post-branching, and has good core line discrimination and take-out characteristics, making it easy to increase the number of cores. An object of the present invention is to provide an optical fiber cable capable of achieving the above.

  In order to achieve the above object, an optical fiber cable according to the present invention includes an interposition having a partition extending radially from the center, an optical fiber tape core housed between the intervening partitions, the interposition and the optical fiber. And a jacket for covering the tape core wire at once.

  According to the optical fiber cable of the present invention, since the optical fiber tape is housed between the intervening partition walls having the partition wall extending in the radial direction from the center, the core wires can be identified and taken out when the number is increased. It becomes easy. And since it is easy to manufacture, it has the same economic efficiency as a conventional slotless optical fiber cable.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an embodiment of an optical fiber cable 100 of the present invention.

  In FIG. 1, reference numeral 11 denotes a synthetic resin such as high-density polyethylene, aluminum, or the like having a substantially cross-shaped cross section in which four partition walls 11a extending in the radial direction from the center are formed at substantially equal intervals in the circumferential direction. The interposition which consists of metal of this is shown. That is, this interposition 11 forms four sections D having a substantially equal cross-sectional area by the partition wall 11a. An optical fiber tape core in which a plurality of (four in the example of the drawing) optical fiber cores 12a are arranged in parallel between the partition walls 11a of the intervening 11, that is, in each section D, and the outer periphery thereof is collectively covered. A plurality of wires 12 (six or seven in the example of the drawing) are stacked and stored. The optical fiber ribbons 12 laminated in each of these sections D can be distinguished from each other by a known method such as a color arrangement of the optical fiber strands 12a in the optical fiber ribbon 12. In addition, the outer periphery 13 is collectively covered with a jacket 13 made of a synthetic resin such as polyethylene or polyvinyl chloride.

  Furthermore, the tension members 14 and 14 made of two steel wires or FRP (fiber reinforced plastic) are vertically embedded in the outer jacket 13 so as to be symmetrical with respect to the center of the cable, In addition, tear strings 15 and 15 made of two polyesters or the like are vertically attached and embedded at positions rotated by approximately 90 ° in the circumferential direction from each of the strength members 14. That is, these two tear strings 15 and 15 are also embedded at positions symmetrical to each other with respect to the center of the cable, like the two strength members 14 and 14. Further, convex portions 13a, 13a are provided on the outer periphery of the jacket 13 in which the tear strings 15, 15 are embedded, so that the positions where the tear strings 15, 15 are embedded can be seen from the outside. Yes.

  When the optical fiber ribbon 12 is taken out from the optical fiber cable 100 configured as described above at the time of intermediate post-branching, the convex portion 13a, 13a provided in the outer jacket 13 is used as a guide to the outer jacket 13. Using a cutter or the like to cut and take out the tear string 15, pulling the tear string 15 outward to tear the outer jacket 13, the outer jacket 13 is removed, and the optical fiber ribbon 12 is taken out. .

  In the optical fiber cable 100 of the present embodiment, the optical fiber ribbon 12 is divided and stored by the partition wall 11a of the intervening 11, and the number of the optical fiber ribbons 12 stored in one section D. Can be easily removed. Further, for example, when the tracer mark is attached or colored to the partition wall 11a, it is sufficient that the optical fiber ribbon 12 can be identified for each section D. The number of the optical fiber ribbons 12 accommodated in one section D. Therefore, the optical fiber tape core 12 has good discrimination.

  Further, this optical fiber cable 100 is a simple manufacturing process, that is, an interposer 11 manufactured in advance, a required number of optical fiber ribbons 12, a tension member 14, and a tear string 15 are extruded. In addition, the optical fiber tape core wire 12 is inserted between the partition walls 11a of the intervening 11, and the tensile strength member 14 and the tear string 15 are introduced along the periphery thereof to form a jacket 13 It can be manufactured by extrusion coating the material in a pipe shape so that the strength member 14 and the tear string 15 are integrated with the resin. Moreover, since the interposition 11 is not required to have high accuracy like the slot rod of the slot type optical fiber cable, it can be easily manufactured by a general-purpose extruder. Therefore, it can be manufactured economically.

  In the present invention, the intervening 11 only needs to form a plurality of partitions by the partition walls 11a. Therefore, the number and shape of the partition walls 11a are not particularly limited to the above example, and the partition walls The width t and height h of 11a are not particularly limited. However, from the viewpoint of the take-out property of the optical fiber ribbon 12, ease of manufacture, side pressure resistance, etc., the intervening 11 has about 3 to 8 partition walls 11 a formed at substantially equal intervals in the circumferential direction. Those having a cross-sectional shape as described above are particularly preferable. The width t of the partition wall 11a is usually about 0.5 mm to 5.0 mm, and the height h is about 2.0 mm to 10.0 mm.

  Further, the interposition 11 may be straight in the length direction, may be twisted in one direction, or may be twisted alternately in the left and right directions. However, from the viewpoint of preventing the movement of the optical fiber ribbon 12 when the optical fiber cable vibrates and the stability of the transmission characteristics when the cable is bent, the optical fiber cable is twisted in one direction or alternately left and right. It is preferable. In the case of twisting in one direction, the twisting pitch is preferably 400 mm to 600 mm. When the twisting pitch is less than 400 mm, the manufacturing workability is deteriorated. The stability of transmission characteristics decreases. Moreover, when twisting alternately right and left, it is preferable that a pitch shall be 150 mm-250 mm. When the pitch is less than 150 mm, the manufacturing workability is lowered, and when it exceeds 250 mm, the effect of suppressing the movement of the core wire and the stability of the transmission characteristics when the cable is bent are lowered.

  In the present invention, for the purpose of protecting the optical fiber ribbon 12 housed between the partition walls 11a of the interposition 11 from the side pressure when the cable is bent, as shown in FIG. The cushioning material 16 may be filled around. Examples of the buffer material 16 include yarns made of single fibers such as aramid fibers, polyarylate fibers, polyparaphenylene benzbisoxazole fibers, polyethylene terephthalate fibers, polyamide fibers (nylon fibers), and polypropylene split yarns. Is used. Jerry can also be used. Among these, the use of yarn is preferable from the viewpoint of buffering effect on side pressure and ease of filling, and polypropylene split yarn is particularly preferable. Such a buffer material 16 also has an effect of preventing the movement of the optical fiber ribbon 12 during cable vibration. When yarn is used as the cushioning material 16, the filling method may be either vertical attachment or twisting. Usually, as shown in FIG. 2, the outer side of the laminated optical fiber ribbon 12 and the jacket A method is used in which the inner peripheral surface side is filled vertically.

  In the present invention, as shown in FIG. 3, the cable support wire 17 may be attached to the jacket 13 of the optical fiber cable 100 of the above-described embodiment. It is good also as a structure where the optical fiber cable 100 of the said embodiment was helically wound around the outer periphery. In FIG. 3, 18 is a covering portion provided on the outer periphery of the cable support wire 17, and 19 is a neck portion that couples the jacket 13 of the optical fiber cable 100 and the covering portion 18 of the cable support wire 17.

  Also in these optical fiber cables with support lines, the optical fiber tape core wire 12 is divided and stored by the partition 11a of the intervening 11 as in the optical fiber cable 100 of the above-described embodiment, and is stored in one section D. Since the number of optical fiber ribbons 12 accommodated is small, they can be easily taken out. Further, for example, when the tracer mark is attached or colored to the partition wall 11a, it is sufficient that the optical fiber ribbon 12 can be identified for each section D. The number of the optical fiber ribbons 12 accommodated in one section D. Therefore, the optical fiber tape core 12 has good discrimination. Furthermore, the production is easy and can be produced economically.

  Next, although the Example of this invention is described concretely, this invention is not limited to the following Examples at all.

Examples 1-3
Three interstitial cross-shaped interventions with a partition wall height h of 3.0 mm and a width t of 1.0 mm are prepared as interpositions, one being straight and the other being one. Directional twisting (twisting pitch 500 mm), the remaining one was left and right alternately twisting (twisting pitch 200 mm). Using these three types of intervention, an optical fiber cable as shown in FIG. 1 was manufactured.

  That is, among the four sections D formed by the partition walls 11a of the cross 11 having a cross section in cross section, one section D has seven optical fiber ribbons 12 and the other three sections D have optical fiber ribbons. 6 is stored in each case, and two high-strength bodies 14 and two tear strings 15 are placed around these 12 in a state in which low-density polyethylene is extrusion-coated as a resin for the jacket 13, An optical fiber cable having a diameter of about 10 mm and a jacket thickness of about 1.5 mm was manufactured. The optical fiber tape core 12 uses a 4-fiber optical fiber ribbon having a width of 1.1 mm and a thickness of 0.3 mm, and the tensile body 14 uses a galvanized steel wire having a diameter of 0.7 mm. As the tear string 15, a 1000 denier triple twist polyester string was used.

Examples 4-6
As shown in FIG. 2, the present embodiment is carried out except that one of the 5000 denier polypropylene split yarns as the cushioning material 16 is vertically inserted into the optical fiber tape core wire 12 in the four sections D of the interposition 11. An optical fiber cable was manufactured in the same manner as in Examples 1 to 3.

Examples 7-9
As the interposition 11, the height h of the partition wall made of three types of high density polyethylene, straight, one-way twist (twist pitch 500 mm), and left and right alternate twist (twist pitch 200 mm) is 4.0 mm and the width t is the same. The optical fiber tape core 12 uses an 8-fiber optical fiber ribbon having a width of 2.1 mm and a thickness of 0.3 mm, and an 8-fiber optical fiber ribbon. An optical fiber cable having an outer diameter of about 12 mm and a jacket thickness of about 1.5 mm, in the same manner as in Examples 1 to 3, except that 10 wires are stacked and stored in the four sections D of the intervening 11 respectively. Manufactured.

  The transmission loss (λ = 1.55 μm) immediately after the production of the optical fiber cable obtained in each of the above examples was measured. In addition, the take-out property of the optical fiber ribbon at the time of intermediate post branching was evaluated, and the loss fluctuation (λ = 1.55 μm) at the time of taking out the optical fiber ribbon was measured. These results are shown in Table 1.

  In Table 1, for comparison with the present invention, the result of the same test for the conventional type optical fiber cable as shown in FIG. 5 is also shown as a comparative example. The optical fiber cable of this comparative example is an assembly of 25 four-core optical fiber ribbons similar to those used in the examples, and six vertical 5000 denier polypropylene split yarns are vertically attached to the periphery. A low density resin for the outer jacket with two strength members made of steel wire with a diameter of 0.7 mm and two tear cords made of polyester cord of 1000 denier 3-strands around it. An optical fiber cable manufactured by extrusion coating of polyethylene and having an outer diameter of about 15 mm and a jacket thickness of about 1.5 mm.

  As is clear from Table 1, the optical fiber cable according to the present invention has good fiber-fiber tape take-out property and core-wire discriminability at the time of intermediate post-branching, and loss fluctuation at the time of the take-off of the fiber cord. Was also not recognized. On the other hand, the optical fiber cable of the comparative example is poorer in the optical fiber tape core wire take-out property and the core wire discriminability than the optical fiber cable according to the present invention, and the loss fluctuation at the time of taking out the core wire is also recognized. It was.

It is sectional drawing which shows one Embodiment of the optical fiber cable of this invention. It is sectional drawing which shows other embodiment of the optical fiber cable of this invention. It is sectional drawing which shows other embodiment of the optical fiber cable of this invention. It is sectional drawing which shows an example of the conventional optical fiber cable. It is sectional drawing which shows the other example of the conventional optical fiber cable.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Interposition, 11a ... Bulkhead, 12 ... Optical fiber ribbon, 13 ... Outer sheath, 14 ... Tensile body, 15 ... Tear string, 16 ... Buffer material, 100 ... Optical fiber cable

Claims (7)

  An interposition having a partition extending radially from the center, an optical fiber tape core housed between the intervening partition walls, and a jacket covering the interposition and the optical fiber tape core in a lump. Features an optical fiber cable.   2. The optical fiber cable according to claim 1, wherein a buffer material is accommodated together with the optical fiber ribbon between the intervening partition walls.   The optical fiber cable according to claim 1 or 2, wherein the interposition is twisted at a predetermined pitch.   The optical fiber cable according to claim 3, wherein the interposition is twisted in one direction at a pitch of 400 mm to 600 mm.   4. The optical fiber cable according to claim 3, wherein the interposition is twisted alternately on the left and right sides at a pitch of 150 mm to 250 mm.   The optical fiber cable according to any one of claims 1 to 5, wherein the intervening partition walls are provided at substantially equal intervals in the circumferential direction.   The optical fiber cable according to any one of claims 1 to 6, wherein the interposition has a substantially cross-shaped cross section.

Images