JP2006171527A - Optical fiber cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber cable in which no bending and stretching distortion is applied to optical fibers, productivity is made high, equipment cost is reduced, coated optical fibers are mutually and easily discriminated even though the number of coated fibers is increased and reliability and cost effectiveness are made superior. <P>SOLUTION: The optical fiber cable 101 includes a coated fiber assembled section 13 which is made by twisting a plurality of coated optical fibers 12 along an SZ direction, high-tensile bodies 14a and 14b which are arranged in parallel with the coated fiber assembled section 13 and a jacket 16 which collectively covers all of the above. The optical fiber cable, in which a plurality of units and a plurality of coated optical fibers are respectively and mutually made identifiable, is provided with a unit assembled section which is made by assembling a plurality of units that are made by assembling a plurality of coated optical fibers and outer circumference is covered, a high-tensile body arranged in parallel with the unit assembled section and a jacket which collectively covers all of the above. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical fiber cable including a plurality of optical fiber core wires.

  In recent years, with the spread of communication services such as the Internet, FTTH (Fiber To The Home), which connects all sections from carriers to general subscriber homes with optical fibers, has been rapidly expanding. Development of various optical fiber cables necessary for construction continues.

  FIG. 15 shows an example of such an optical fiber cable, which was developed as an aerial optical drop cable for drawing and wiring from a wiring system cable installed overhead to a customer's house. As shown in the figure, this optical fiber cable has a single-core optical fiber core 1 sandwiched between tensile strength members 2 and 2 above and below it, and further a support wire 3 disposed on the outer periphery thereof. It has a structure in which a jacket 4 is provided by batch extrusion coating of a thermoplastic resin such as polyethylene. A connecting portion (neck portion) 7 that divides the cable into a supporting wire portion 5 and a cable portion 6 is provided between the supporting wire 3 and the strength member 2 of the cable. At notches 8 and 8 for tearing are provided at substantially central portions of both side surfaces.

  Further, FIG. 16 was developed as an underground optical drop cable for drawing into a subscriber's house from a wiring system cable installed underground, or a so-called optical indoor cable for indoor wiring. It is comprised similarly to the cable part 6 of the optical fiber cable shown.

  In such an optical drop cable, since the strength member 2 is disposed with the optical fiber core 1 sandwiched therebetween, an increase in transmission loss of the optical fiber due to a temperature change, or when the cable portion 6 or the cable is wired indoors. The disconnection of the optical fiber due to the tensile stress can be prevented, and the notch 8 for tearing is provided, so that the outer cover 4 is torn in the width direction of the cable at the time of cable end processing, etc. It has the characteristics that the core wire 1 can be easily taken out.

  By the way, in the cables shown in FIGS. 15 and 16, one single-core optical fiber 1 is housed in the cable. Cables have been developed to increase the number of optical fiber cores by using a unit in which optical fiber cores are gathered around an intervening unit or a unit in which a plurality of optical fiber cores are bundled ( (See Patent Documents 1 to 3.)

  In such a multi-core optical fiber cable, when the cable is bent, local strain is easily applied to the optical fiber. Therefore, the optical fiber core wires are generally twisted in one direction. In particular, when the number of cores exceeds 3 to 4, it is practically impossible to use without adding twist.

  In addition, in a multi-fiber optical fiber cable, in order to improve the workability of connecting the optical fiber cores, the surfaces of the optical fiber core wires that are gathered are colored different colors such as red, green, yellow, and blue. By using fiber cores (colored cores), the optical fiber cores can be distinguished from each other.

  However, such a conventional multi-core optical fiber cable has a structure in which the optical fiber cores are twisted in one direction and no extra length is inserted into the optical fiber. There was a risk of stretching strain on the fiber. Moreover, in order to twist the optical fiber cores in one direction, a medium to large-scale twisting facility is necessary (the optical fiber core wire feeding device needs to be rotated), the productivity is low, and the equipment cost is low. There was also the difficulty of becoming higher.

On the other hand, regarding the mutual identification of the optical fiber cores by coloring, when the number of cores increases, the number of colors to be used increases, so that the identification takes time, and in some cases, there is a possibility that an identification error occurs. In particular, in a dark place, those colored in dark colors such as blue, green, and purple are difficult to identify, and identification errors are likely to occur. For this reason, the number of colors to be used is reduced by specifying the arrangement order of the colored cores, but the outer diameter of the optical fiber cores may be very thin (usually 250 μm), It is not easy to visually identify the sequence.
JP 2003-161867 A JP 2003-227777 A JP 2003-227985 A

  As described above, a multi-core optical fiber cable having a plurality of optical fiber cores has been developed for withdrawal to a building or a condominium or on-site wiring. However, the conventional multi-core optical fiber cable requires a medium to large-scale twisting equipment that easily stretches and strains the optical fiber at the time of cable wiring, and the productivity is low and the equipment cost is high. However, there is still a point to be improved in terms of both characteristics and cost, such as the discriminability between the optical fiber cores is reduced.

  The present invention has been made in response to such problems of the prior art, and does not add strain to the optical fiber when the cable is bent or pulled, and requires a large-scale twisting facility. An object of the present invention is to provide a multi-core optical fiber cable excellent in reliability and economy. Another object of the present invention is to provide an optical fiber cable excellent in distinguishability between optical fiber cores, which can easily identify optical fiber cores even when the number of cores increases. .

  In order to achieve the above object, an optical fiber cable according to a first invention of the present application includes a core assembly portion formed by aggregating a plurality of optical fiber cores, and a tensile body disposed in parallel with the core assembly. And a jacket for covering them all together, and the plurality of optical fiber cores are twisted in the SZ direction.

  Further, the optical fiber cable of the second invention of the present application includes a unit assembly portion formed by collecting a plurality of optical fiber cores and a plurality of units coated on the outer periphery thereof, and in parallel with the unit assembly portion. A plurality of units and a plurality of optical fiber cores are provided so as to be distinguishable from each other.

  According to the optical fiber cable of the present invention, since the optical fiber core wire is twisted in the SZ direction, not only bending strain but also elongation strain can be suppressed. Moreover, since a small-scale twisting apparatus is sufficient compared with unidirectional twisting, productivity is high and equipment cost can be reduced. In addition, a plurality of units, each of which is a collection of a plurality of optical fiber cores, are assembled so that a plurality of units and a plurality of optical fiber cores in each unit can be distinguished from each other. Therefore, even if the number of cores increases, the optical fiber cores can be easily distinguished from each other.

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

  FIG. 1 is a cross-sectional view showing a first embodiment of the optical fiber cable of the present invention, and FIG. 2 is an enlarged cross-sectional view showing a main part thereof.

  As shown in FIG. 1 and FIG. 2, the optical drop cable 101 of this embodiment has a plurality of single-core optical fiber wires 12 (in FIG. 1) around an intervention 11 made of, for example, polyethylene. 12) 1st strength member 14a which consists of the core wire gathering part 13 which gathers, and the steel wire or FRP (fiber reinforced plastic) etc. which were arranged in parallel at intervals up and down the core wire gathering part 13 And the second tensile strength member 14b, the support wire 15 made of a steel wire or the like arranged in parallel at a distance above the first tensile strength member 14a, and the thermoplastic resin that is extrusion-coated collectively on the outer periphery thereof. And a jacket 16 made of resin. Between the first strength member 14a of the jacket 16 and the support wire 15, a cable is connected to the support wire portion 17 including the support wire 15, the core wire assembly portion 13, the first and second strength members 14a, A neck portion 19 is provided to divide the cable portion 18 including 14 b and to easily separate the support wire portion 17 from the cable portion 18. Further, a tear notch 20 is provided in the approximate center of both side surfaces of the jacket 16 of the cable portion 18.

  In this embodiment, the single-core optical fiber cores 12 are assembled by being twisted around the interposition 11 in the SZ direction, and a colored layer is provided on the surface as the single-core optical fiber cores 12. Colored cords are used. The colored layer is colored in different colors such as red, green, purple, yellow,... For each of the cores, thereby making it possible to identify each single-core optical fiber 12 from each other.

  In addition, you may make it wind further around the single core optical fiber core wire 12 as needed. Moreover, as a thermoplastic resin which comprises the jacket 16, polyethylene, a polypropylene, an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-propylene copolymer, etc. are mentioned. These resins may contain a flame retardant, a colorant and the like.

  In the optical fiber cable 101 of this embodiment, since the single-core optical fiber core wire 12 is twisted in the SZ direction, not only a local bending strain is added to the optical fiber when the cable is bent. Further, it is possible to suppress the elongation strain from being applied to the optical fiber when the cable is pulled. Also, when the single-core optical fiber 12 is twisted in the SZ direction, it does not require equipment for rotating the optical fiber core-feeding device as in the case of conventional unidirectional twist. The equipment cost can be reduced.

  FIG. 3 is a cross-sectional view according to the second embodiment of the present invention, and parts common to FIG.

  The optical fiber cable 102 according to the present embodiment is used as a so-called underground drop cable wired underground, or an optical indoor cable for wiring indoors after being pulled in by an underground or overhead optical drop cable. The configuration is the same as that of the first embodiment shown in FIG. 1 except that the support line portion 17 and the neck portion 19 are not provided.

  That is, a core assembly 13 formed by gathering a plurality of optical fiber cores 12 (12 in FIG. 3) around an intervening 11 made of polyethylene or the like, and this core assembly 13 The first tensile strength member 14a and the second tensile strength member 14b made of steel wire or FRP, which are arranged in parallel at intervals above and below the outer periphery, and an outer portion made of a thermoplastic resin that is extrusion-coated collectively on the outer periphery thereof. A tearing notch 20 is provided at substantially the center of both side surfaces of the jacket 16. The single-core optical fiber core 12 is assembled by being twisted in the SZ direction around the interposition 11, and a single-core optical fiber 12 having a colored layer provided on the surface is used as the single-core optical fiber core 12. Has been. The colored layers of the single-core optical fibers 12 are colored in different colors such as red, green, purple, yellow, and so on, so that the single-core optical fibers 12 can be distinguished from each other. It has become.

  Also in the optical fiber cable 102 configured in this manner, as in the case of the first embodiment, the single-core optical fiber core wire 12 is twisted in the SZ direction. As a result, not only bending strain is added, but also elongation strain is added to the optical fiber when the cable is pulled. Also, when the single-core optical fiber 12 is twisted in the SZ direction, it does not require equipment for rotating the optical fiber core-feeding device as in the case of conventional unidirectional twist. The equipment cost can be reduced.

  In the present invention, the number of single-core optical fiber cores 12 to be assembled is not particularly limited as long as it is plural, that is, two or more. Further, in each of the above-described embodiments, the core assembly 13 has a structure in which the single-core optical fiber 12 is twisted around the intervening 11, but as shown in FIG. The fiber core wires 12 may be simply assembled and SZ twisted. Further, as illustrated in FIG. 5, an optical fiber ribbon 12 </ b> A may be used instead of the single-fiber ribbon 12. In the example shown in FIG. 5, a plurality of optical fiber ribbons 12 </ b> A (in FIG. 5, three in FIG. 5), in which a plurality (four in FIG. 5) of optical fiber strands are arranged in parallel and the outer periphery is collectively coated. The core wire assembly 13 is formed by stacking and twisting in the SZ direction.

  Furthermore, in the present invention, as shown in FIGS. 6 to 8, a buffer material 21 is arranged around the twisted single optical fiber core 12 or the optical fiber tape core 12A, and the outer cover 16 is disposed outside thereof. May be provided. 6, 7, and 8, the cushioning material 21 is disposed around the core assembly 13 in the examples illustrated in FIGS. 2, 4, and 5, respectively. By disposing the buffer material 21, it is possible to prevent a decrease in transmission characteristics of the optical fiber due to external stress. The buffer material 21 may be a yarn such as a polypropylene string, an aramid fiber, or a polyester string, or a string-like body.

  Furthermore, in the example described above, each of the two strength members 12a and 12b is arranged in parallel with a space between the upper and lower sides of the core assembly 13, with a single core light. You may make it arrange | position only in either one of the upper and lower sides of the fiber core wire 12 or the optical fiber tape core wire 12A.

  FIG. 9 and FIG. 10 are sectional views showing third and fourth embodiments of the optical fiber cable of the present invention, respectively, and parts common to FIG.

  As shown in FIG. 9, the optical fiber cable 103 according to the third embodiment is an optical fiber tape core in which a plurality of (four in FIG. 9) optical fiber strands are arranged in parallel and the outer periphery thereof is collectively covered. A plurality of the wires 12A (10 in FIG. 9) are gathered to form the core wire gathering portion 13, and the cushioning material 21 is disposed around the wire 12A, and the outer cover 16 made of a thermoplastic resin such as polyethylene is applied to the outside thereof. Has the structure. Strength members 14a and 14b made of two steel wires or FRP and tearing cords 22a and 22b made of polyester cords are vertically embedded in the jacket 16, and the tearing cords 22a and 22b are embedded. On the outer periphery of the outer cover 16 in a portion where the is embedded, a convex portion 23 indicating the embedded position is provided. And in this embodiment, the optical fiber tape core wire 12A which comprises the core wire aggregate | assembly part 13 is twisted in the SZ direction in the laminated state. In the example of FIG. 9, six optical fiber ribbons 12A are laminated in the thickness direction, and two optical fiber ribbons 12A are laminated and assembled on both side surfaces in the SZ direction. .

  Moreover, the optical fiber cable 104 of 4th Embodiment has the structure which attached the support wire 15 which consists of a steel wire etc. to the jacket 16 of the optical fiber cable 103 of 3rd Embodiment, as shown in FIG. . A coating 24 provided integrally with the jacket 16 is provided on the outer periphery of the support wire 15, and a neck portion 19 is provided between the coating 24 and the jacket 16.

  Also in the optical fiber cables 103 and 104 of the third and fourth embodiments configured as described above, since the optical fiber ribbon 12A is twisted in the SZ direction, the optical fiber cables 103 and 104 are locally attached to the optical fiber when the cable is bent. As a result, not only bending strain is added, but also elongation strain is added to the optical fiber when the cable is pulled. Also, when the single-core optical fiber 12 is twisted in the SZ direction, it does not require equipment for rotating the optical fiber core-feeding device as in the case of conventional unidirectional twist. The equipment cost can be reduced.

  FIG. 11 is a cross-sectional view showing the main configuration of the fifth embodiment of the optical fiber cable of the present invention.

  The optical fiber cable according to the present embodiment is the same as that in the first and second embodiments described above, except that the core assembly 13 is configured as shown in FIG. The configuration is the same as in each embodiment. Hereinafter, the difference will be mainly described.

  As shown in FIG. 11, in the present embodiment, the core assembly 13 includes a unit 26 in which a plurality of single-core optical fibers 12 (five in FIG. 11) are assembled and a coating 25 is applied to the outer periphery thereof. It is composed of a plurality (three in FIG. 11). The plurality of units 26 and the plurality of single-core optical fibers 12 in each unit are all twisted in the SZ direction. The coating 25 of the unit 26 is configured by extrusion coating with a thermoplastic resin such as polyethylene or winding of a resin tape. The method of winding the resin tape may be either horizontal winding or vertical attachment.

  In this embodiment, for each unit 26, a colored core wire having a colored layer colored in a different color on the surface is used as the single-core optical fiber core wire 12, whereby each unit 26 The plurality of single-core optical fiber core wires 12 can be distinguished from each other within 26. Also, each coating 25 constituting each unit 26 is also colored in different colors such as red, blue, yellow..., So that each single-core optical fiber 12 can be identified between the units 26. It has become.

  In the optical fiber cable configured as described above, a plurality of units 26 each including a plurality of single-core optical fiber cores 12 are assembled, and a plurality of single-core optical fibers are provided between the units 26 and in each unit 26. Since the cores 12 can be discriminated from each other, the single-core optical fiber cores 12 can be identified with a small number of colors. Can be easily identified.

  In addition, since the plurality of units 26 and the plurality of single-core optical fibers 12 in each unit 26 are all twisted in the SZ direction, local bending strain is applied to the optical fiber when the cable is bent. In addition to this, it is possible to suppress elongation strain from being applied to the optical fiber when the cable is pulled. Further, when the unit 26 and the single-core optical fiber core wire 12 are twisted in the SZ direction, large-scale equipment as in the case of unidirectional twisting is not required, so that productivity is high and equipment costs are greatly increased. Nor.

  In the example of FIG. 11, the units 26 can be identified by the coloring applied to the coating 25 of the unit 26. May be. Moreover, it is good also as a structure which can be discriminate | determined by the shape and the combination of a shape and color irrespective of a color. (A)-(e) shown in FIG. 12 shows the example of the parameter | index which can be identified with a shape.

  Further, the number of units 26 and the number of single-core optical fibers 12 gathered in each unit 26 are not particularly limited to the above example, and further, as shown in FIG. It is good also as a structure which gathers 26 centering on the intervention 27 which consists of synthetic fiber or a synthetic resin. In the example shown in FIG. 14, three single-core optical fibers 12 are gathered and five units 26 each having a coating 25 on the outer periphery are gathered, with an interposition 27 as the center. Further, as illustrated in FIG. 13, an optical fiber ribbon 12 </ b> A may be used in place of the single-fiber ribbon 12. In the example shown in FIG. 13, a plurality (two in FIG. 13) of optical fiber ribbons 12A (two in FIG. 13) are arranged in parallel and the outer periphery thereof is collectively covered. The core wire assembly portion 13 is formed by gathering and twisting in the SZ direction.

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

Example 1
An optical drop cable having the structure shown in FIG. 1 was manufactured. For the single-core optical fiber 12, eight kinds of colored cores having an outer diameter of 0.25 mm and different colored layers are used, and for the intervening 11, polyethylene intervention having an outer diameter of 0.7 mm is used. Aramid-FRP with an outer diameter of 0.4 mm was used for the second strength members 14 a and 14 b, and a galvanized single steel wire with an outer diameter of 1.2 mm was used for the support wire 15.
8 types of colored core wires are SZ twisted around the interposition 11, and the two strength members 14a and 14b and the support wire 15 are introduced into the extruder in a state of being arranged in parallel as shown in FIG. Then, black flame retardant polyethylene was collectively extrusion coated on the outer periphery to produce an optical fiber cable having a total width of about 3 mm and a height of about 7 mm.

Examples 2-5
2 types, 4 types, 8 types, and 12 types of colored core wires having an outer diameter of 0.25 mm and different colored layers are prepared, and an optical fiber cable having a core assembly 13 as shown in FIG. 4 is manufactured. did. As the first and second strength members 14a and 14b and the support line 15, the same ones as in Example 1 were used.
While two, four, eight, and twelve types of colored core wires are SZ twisted, two strength members 14a, 14b and a support wire 15 are arranged in parallel as shown in FIG. The fiber was introduced into an extruder, and black flame-retardant polyethylene was coated on the outer periphery at the same time to produce 2-fiber, 4-core, 8-core and 12-core optical fiber cables. The obtained two-core optical fiber cable has an overall width of about 2 mm and the same height of about 5 mm, and the four-core optical fiber cable has an overall width of about 2 mm and the same height of about 5 mm. The overall width was about 2 mm and the height was about 6 mm, and the 12-fiber optical fiber cable had an overall width of about 2 mm and the same height of about 6 mm.

Example 6
Two types of colored two-core optical fiber ribbons having a width of 0.6 mm and a thickness of 0.4 mm and different colored layers are prepared, and an optical fiber cable having a cord assembly 13 as shown in FIG. 5 is manufactured. did. As the first and second strength members 14a and 14b and the support line 15, the same ones as in Example 1 were used.
While laminating and twisting two types of colored optical fiber ribbons and SZ twisting, the two strength members 14a and 14b and the support wire 15 are introduced into the extruder in a state of being arranged in parallel as shown in FIG. A black flame retardant polyethylene was collectively extrusion coated on the outer periphery to produce an optical fiber cable having a total width of about 3 mm and a height of about 6 mm.

Examples 7-9
Two types, three types, and four types of four-core colored optical fiber ribbons each having a width of 1.1 mm and a thickness of 0.3 mm and having different colored layer colors are prepared. An optical fiber cable having As the first and second strength members 14a and 14b and the support line 15, the same ones as in Example 1 were used.
2 types, 3 types and 4 types of colored optical fiber ribbons were laminated and SZ twisted, and two strength members 14a and 14b and a support wire 15 were arranged in parallel as shown in FIG. The fiber was introduced into an extruder in a state, and black flame-retardant polyethylene was collectively extrusion coated on the outer periphery thereof to produce 8-core, 12-core, and 16-core optical fiber cables. The obtained 8-core optical fiber cable has an overall width of about 2 mm and the same height of about 6 mm, and the 12-core optical fiber cable has an overall width of about 3 mm and the same height of about 7 mm. The overall width was about 4 mm and the height was about 7 mm.

  When each of the obtained optical fiber cables was subjected to a temperature cycle of −30 ° C. to + 70 ° C. three times and examined for an increase in transmission loss, the increase in transmission loss was 0.04 dB / km or less, both of which were good. Had characteristics.

It is sectional drawing which shows 1st Embodiment of the optical fiber cable of this invention. It is sectional drawing which expands and shows the principal part of the optical fiber cable shown in FIG. It is sectional drawing which shows 2nd Embodiment of the optical fiber cable of this invention. It is sectional drawing which shows the modification of the 1st and 2nd embodiment of this invention. It is sectional drawing which shows the modification of the 1st and 2nd embodiment of this invention. It is sectional drawing which shows the modification of the 1st and 2nd embodiment of this invention. It is sectional drawing which shows the modification of the 1st and 2nd embodiment of this invention. It is sectional drawing which shows the modification of the 1st and 2nd embodiment of this invention. It is sectional drawing which shows 3rd Embodiment of the optical fiber cable of this invention. It is sectional drawing which shows 4th Embodiment of the optical fiber cable of this invention. It is sectional drawing which shows the principal part of 5th Embodiment of the optical fiber cable of this invention. It is a figure which shows the parameter | index example for the identification of the unit in the 5th Embodiment of this invention. It is sectional drawing which shows the modification of the 5th Embodiment of this invention. It is sectional drawing which shows the modification of the 5th Embodiment 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 12 ... Single-core optical fiber core, 12A ... Optical fiber tape core wire, 13 ... Core wire assembly part, 14a ... 1st tensile body, 14b ... 2nd tensile body, 15 ... Support wire, 16 ... Outer sheath, 21 ... cushioning material, 25 ... coating, 26 ... unit, 101-104 ... optical fiber cable

Claims (5)

A core assembly portion formed by collecting a plurality of optical fiber core wires, a tensile body arranged in parallel to the core assembly portion, and a jacket covering them all at once;
The optical fiber cable, wherein the plurality of optical fiber core wires are twisted in the SZ direction.   The optical fiber cable according to claim 1, wherein a buffer material is disposed around the core assembly. A unit assembly part formed by collecting a plurality of optical fiber cores and a plurality of units coated on the outer periphery thereof, a tensile body arranged in parallel to the unit assembly part, and a jacket covering them all together And
The plurality of units and the plurality of optical fiber cores in each unit are configured to be distinguishable from each other.   The optical fiber cable according to claim 3, wherein the plurality of optical fiber cores in each unit are twisted in the SZ direction.   The optical fiber cable according to claim 3 or 4, wherein a buffer material is disposed around the unit assembly portion.

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