TW202331325A - Optical fiber assembly, optical fiber cable, and method for manufacturing optical fiber assembly - Google Patents

Abstract

This optical fiber assembly comprises: a plurality of optical fibers; and a plurality of intermittently fixing tape core wires including a plurality of fixing parts for intermittently fixing the optical fibers in the longitudinal direction. The intermittently fixing tape core wires are periodically twisted. In a cross-section perpendicular to the longitudinal direction and in one of the intermittently fixing tape core wires, when the middle point and the center of gravity between two of the optical fibers located at both ends are respectively denoted by M and G, a vector being defined by the middle point M as the start point and the center of gravity G as the end point is denoted by MG, and the magnitude of the vector MG is defined as the scalar amount LT, each periodical twisting includes at least one set of the intermittently fixing tape core wires, in which the magnitude relationship in the scalar amount LT switches.

Description

Optical fiber assembly, optical fiber cable, and method for manufacturing optical fiber assembly

The invention relates to an optical fiber assembly, an optical fiber cable, and a method for manufacturing the optical fiber assembly. This application claims priority based on Japanese Patent Application No. 2021-212150 filed in Japan on December 27, 2021, the contents of which are incorporated herein.

Patent Document 1 discloses an optical fiber cable including a plurality of optical fiber units collectively covered with an outer covering. Each optical fiber unit includes a plurality of intermittent fixed ribbon cores. prior art literature patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2014-16530

The problem to be solved by the invention

However, for example, in the optical fiber cable disclosed in Patent Document 1, when bending occurs or the sheath shrinks in a low-temperature environment, strain may concentrate on specific intermittently fixed tape cores. Such concentration of strain may increase the maximum transmission loss of the optical fiber cable (optical fiber assembly).

The present invention was made in consideration of such circumstances, and an object of the present invention is to provide an optical fiber assembly, an optical fiber cable, and a method for manufacturing an optical fiber assembly capable of suppressing an increase in the maximum transmission loss. means to solve problems

In order to solve the above-mentioned problems, an optical fiber assembly according to an aspect of the present invention includes a plurality of intermittently fixed tape cores, the plurality of intermittently fixed tape cores include a plurality of optical fibers and a plurality of optical fibers that intermittently fix the plurality of optical fibers in the longitudinal direction. In the fixing part, the plurality of intermittent fixed belt core wires are periodically twisted, and in the section perpendicular to the aforementioned long side direction, one of the aforementioned plurality of intermittent fixed belt core wires is located at two ends of the intermittent fixed belt core wires. The midpoint of the above-mentioned optical fiber is set as M, the center of gravity is set as G, the vector with the aforementioned midpoint M as the starting point and the aforementioned center of gravity G as the end point is set as MG, and when the magnitude of the aforementioned vector MG is set as the scalar LT, In each of the twisting cycles, at least one set of the intermittent fixed tape core wires in which the magnitude relationship of the scalar LT is reversed exists.

In addition, the manufacturing method of an optical fiber assembly according to an aspect of the present invention is to include at least one set of intermittently fixed tape cores in which the magnitude relationship of the scalar LT is reversed in each of the twisting cycles. The plurality of intermittently fixed core wires are periodically twisted. Invention effect

According to the above aspects of the present invention, it is possible to provide an optical fiber assembly, an optical fiber cable, and a method of manufacturing an optical fiber assembly capable of suppressing an increase in the maximum transmission loss.

form for carrying out the invention

Hereinafter, an optical fiber assembly 1 and an optical fiber cable 100 according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1 , an optical fiber cable 100 of the present embodiment includes an optical fiber assembly 1 including a plurality of optical fiber units U. As shown in FIG. 2 , each optical fiber unit U has a plurality of intermittent fixed tape core wires 10 . In other words, a plurality of intermittent fixed tape core wires 10 constitute a plurality of optical fiber units U. In addition, each intermittent fixed tape core wire 10 includes a plurality of optical fibers 11 . In other words, a plurality of optical fibers 11 constitute a plurality of intermittent fixed tape core wires 10 . The outer diameter of each optical fiber 11 is, for example, 250 μm. However, the outer diameter of the optical fiber 11 may be 200 μm or other values.

(direction definition) Here, in this embodiment, the longitudinal direction of the optical fiber assembly 1 (optical fiber cable 100 ) is simply referred to as the longitudinal direction Z. The longitudinal direction Z is also a direction parallel to the central axis O of the optical fiber assembly 1 (optical fiber cable 100 ). One direction along the longitudinal direction Z is referred to as the direction of +Z or the front. The direction opposite to the +Z direction is referred to as the -Z direction or the rear. A section perpendicular to the longitudinal direction Z is called a transverse section. Viewing the cross-section from the longitudinal direction Z is called a cross-sectional viewing angle. A direction perpendicular to the central axis O of the optical fiber assembly 1 (optical fiber cable 100 ) is called a radial direction. Along the radial direction, the direction closer to the central axis O is referred to as the radially inner side, and the direction farther from the central axis O is referred to as the radially outer side. Seen from the longitudinal direction Z, the direction around the central axis O is referred to as the circumferential direction.

As shown in FIG. 1 , the optical fiber cable 100 of this embodiment is a so-called slotless optical fiber. That is, the optical fiber cable 100 of this embodiment does not have a groove bar forming a groove (groove) for accommodating the optical fiber 11 (intermittent fixed tape core wire 10). However, the fiber optic cable 100 can also be a grooved fiber with grooved rods. In this case, the optical fiber assembly 1 of this embodiment can also be accommodated in the groove of the optical fiber cable 100 .

As shown in FIG. 1 , the optical fiber cable 100 of this embodiment includes: the above-mentioned optical fiber assembly 1 , a crimping member 120 covering the optical fiber assembly 1 , and an outer covering and accommodating the optical fiber assembly 1 through the crimping member 120 . Quilt 110. That is, the optical fiber assembly 1 can be regarded as a part of the optical fiber cable 100 except for the sheath 110 and the crimping member 120 . In addition, the optical fiber assembly 1 and crimp 120 may be collectively referred to as a core material.

The crimp 120 is a tape-shaped member, and bundles a plurality of optical fiber units U. The type of the crimping member 120 is not particularly limited as long as the optical fiber units U can be bundled, and the crimping member 120 may also be non-woven fabric or polyester tape, for example. The crimping member 120 can also have water absorption. The crimping member 120 can also wind the optical fiber assembly 1 longitudinally or transversely, for example. For example, when the crimping member 120 is an adhesive tape extending in the longitudinal direction Z, the crimping member 120 may be formed in a cylindrical shape covering the optical fiber unit U. In this case, both ends of the crimping member 120 in the circumferential direction may overlap each other to form a covering portion. In addition, the crimping member 120 may not be a ribbon, but may be a tube forming body covering the optical fiber unit U. Since the optical fiber unit U is covered by the crimping member 120 in the longitudinal direction Z, the optical fiber 11 can be protected. In addition, there may be a position in the longitudinal direction Z where the optical fiber 11 is not covered by the crimping member 120 , and the optical fiber cable 100 may not have the crimping member 120 .

As the material of the outer covering 110, polyethylene (PE), polypropylene (PP), ethylene ethyl acrylate copolymer (EEA), ethylene vinyl acetate copolymer (EVA), ethylene propylene copolymer (EP), etc. can be used. Polyolefin (PO) resin, polyvinyl chloride (PVC), etc. In addition, a mixture (alloy, mixture) of the above-mentioned resins may be used to form the outer covering 110 . Also, various additives may be added to the outer covering 110 according to the purpose. As an example of an additive, a flame retardant, a coloring agent, an anti-deterioration agent, an inorganic filler, etc. are mentioned. Also, the outer covering 110 may have a two-layer structure or other multi-layer structures. For example, a protective layer covering the outer covering 110 may also be provided outside the outer covering 110 (the first outer covering) in the illustrated example, and a second outer covering covering the protective layer may be provided outside the protective layer. Quilt pieces. The protective layer can also be made of, for example, metal or fiber reinforced plastic (FRP). Alternatively, the outer covering 110 may not have a protective layer, but only be formed by a plurality of outer coverings.

The outer shape of the quilt 110 in this embodiment is substantially circular when viewed in cross section, except for the protrusion 110a described later. However, the shape of the outer covering material 110 may be appropriately changed. As shown in FIG. 1 , a plurality of (four in the illustrated example) tensile members 130 and a pair of tear cords 140 are arranged in the quilt 110 in addition to the present embodiment.

The tensile body 130 is a member having a spring constant or a higher tensile strength in the longitudinal direction Z than the outer covering 110 . As the material of the tensile body 130 , for example, metal wires (steel wires, etc.), materials with bundled metal wires, glass fibers, or materials with bundled glass fibers, etc. can be used. Alternatively, fiber reinforced plastic (FRP) or the like may also be used as the tensile body 130 . When tension is applied to the optical fiber assembly 1 (optical fiber cable 100 ) along the longitudinal direction Z, the tension-resistant body 130 has the function of protecting the optical fibers 11 by receiving the tension. A plurality of tensile members 130 are arranged on the outer covering 110 . The plurality of tensile members 130 in this embodiment are disposed so as to sandwich the optical fiber assembly 1 therebetween in the radial direction. However, a plurality of tensile members 130 may also be isotropically arranged on the jacket 110 to surround the optical fiber assembly 1 (core material). In addition, the tensile body 130 may not be embedded in the outer covering. For example, the tensile body 130 can also be included in the center or core material of the optical fiber assembly 1 . Alternatively, depending on the application of the optical fiber cable 100 , the optical fiber cable 100 may not have the tensile body 130 .

The tear cord 140 is a member used to tear the outer jacket 110 . As the material of the rip cord 140 , for example, a thread of synthetic fiber (such as polyester), polypropylene (PP), or a cylindrical rod made of nylon can be used. The tear cord 140 is disposed on the outer jacket 110 . In addition, from a cross-sectional perspective, the tearing cord 140 can also be configured to be completely embedded in the outer covering member 110 , or be configured to be partially exposed from the outer peripheral surface or inner peripheral surface of the outer covering member 110 . One of the pairs of rip cords 140 in this embodiment is disposed so as to sandwich the optical fiber assembly 1 in the radial direction. Moreover, in the circumferential direction, the positions of the tension-resistant bodies 130 and the tearing cords 140 are staggered from each other. In addition, the number of tear cords 140 may be one, or three or more. Also, the tear cord 140 may not be embedded in the outer covering 110 . For example, the rip cord 140 can also be attached longitudinally to the optical fiber assembly 1 . Alternatively, the fiber optic cable 100 may not have the rip cord 140 .

In the outer covering material 110 of this embodiment, a pair of protrusions 110a protruding radially outward from the outer peripheral surface of the outer covering material 110 are provided. The positions of the protrusions 110a in the circumferential direction and the positions of the tear cords 140 correspond to each other. The protrusion 110 a serves as a mark for the user to easily identify the position of the tear cord 140 from the outside of the optical fiber cable 100 . In addition, the outer cover 110 may not have the protrusion 110a. In this case, the linear coloring of the outer covering material 110 may be used instead of the protrusion 110a. However, the outer covering 110 may not have the protrusion 110a, and the outer covering 110 may not be colored.

As described above, the optical fiber assembly 1 has a plurality of (twelve in the example shown in FIG. 1 ) optical fiber units U. As shown in FIG. 1 , an optical fiber assembly 1 including a plurality of optical fiber units U of this embodiment has a two-layer structure. That is, the plurality of optical fiber units U includes a plurality (nine in the illustrated example) of outer units Uout and a plurality (three in the illustrated example) of inner units Uin. Each outer layer unit Uout is located on the outer periphery of the optical fiber assembly 1 . The plurality of inner-layer units Uin are surrounded by the plurality of outer-layer units Uout from the outside in the radial direction. That is to say, the plurality of inner layer units Uin are located at the center of the optical fiber assembly 1 in the cross-sectional view. However, the number of inner units Uin and the number of outer units Uout can be changed appropriately. In addition, the optical fiber assembly 1 does not need to have a two-layer structure.

As shown in FIG. 2 , the optical fiber unit U of this embodiment includes the above-mentioned plurality of intermittent fixed tape core wires 10 and a bundle material 20 for bundling the plurality of intermittent fixed tape core wires 10. The intermittent fixed tape included in one optical fiber unit U The number of core wires 10 should just be 2 or more, and may be 6 etc., for example.

The bundle material 20 is a member capable of bundling a plurality of intermittent fixed tape core wires 10 . As the bundle material 20 , for example, a wire-shaped, rope-shaped, or belt-shaped member can be used. In this embodiment, the intermittent fixed tape core wires 10 are wound and bundled by a bundle material 20 . However, the configuration in which the bundle material 20 bundles the intermittently fixed tape core wires 10 is not limited to the illustrated example. For example, the bundle material 20 may be wound helically around the intermittent fixed tape core wire 10 . Alternatively, the optical fiber unit U may not have the bundle material 20 . In this case, for example, in the optical fiber unit U, the intermittent fixed tape core wires 10 may be bundled by twisting a plurality of intermittent fixed tape core wires 10 .

In addition, the optical fiber assembly 1 may not have the optical fiber unit U. In other words, the plurality of intermittent fixed tape core wires 10 may not constitute the optical fiber unit U. That is, the optical fiber assembly 1 may also have a structure in which the crimping member 120 or the sheathing member 110 directly covers the intermittent fixed tape core wire 10 . Also, in the example shown in FIG. 1, the inner unit Uin is formed in a fan shape, and the outer unit Uout is formed in a quadrangular shape. Not limited to the illustrated example, the cross-sectional shape of the optical fiber unit U may be circular, elliptical, or polygonal. In addition, even when the optical fibers 11 are bundled by the bundle material 20 , they appropriately move to an empty space inside the sheath material 110 while deforming the bundle material 20 . Therefore, for example, as shown in FIG. 5 , the cross-sectional shape of the optical fiber unit U can also be bent.

As shown in FIG. 3 , each intermittent fixed tape core wire 10 includes a plurality of (twelve in the illustrated example) optical fibers 11 and a plurality of fixing parts 12 . Each optical fiber 11 has a core material and a cladding material. A covering layer such as resin is provided on the outer periphery of the covering material. In the state before the optical fiber assembly 1 is formed, the plurality of optical fibers 11 in the intermittently fixed tape core wire 10 are arranged in a row. Thereby, the intermittently fixed tape core wire 10 has a tape-like shape. Hereinafter, for easier description, the direction in which the optical fibers 11 are arranged in the intermittently fixed tape core wire 10 may be referred to as the tape width direction W.

Each fixing portion 12 fixes two adjacent optical fibers 11 in the tape width direction W to each other. A gap may be provided between two adjacent optical fibers 11 . In this case, the plurality of fixing portions 12 are intermittently arranged in the gap in the longitudinal direction Z. As shown in FIG. Alternatively, there may be no gap between adjacent two optical fibers 11 . Also, two optical fibers 11 may be continuously fixed in the longitudinal direction Z to constitute an optical fiber group, and a plurality of optical fiber groups may be intermittently fixed by a plurality of fixing parts 12 . As shown in FIG. 3 , the plurality of fixing portions 12 are intermittently arranged two-dimensionally in the longitudinal direction Z and the tape width direction W. As shown in FIG. In addition, the arrangement of the fixing part 12 is not limited to the example of FIG. 3, It can change suitably. In addition, the arrangement pattern of the fixed portion 12 may not be a constant pattern in the longitudinal direction Z or the tape width direction W. The arrangement pattern of the fixed portion 12 may not be a fixed pattern between different intermittently fixed tape core wires 10 . For example, UV curable resin can also be used as the material of the fixing portion 12 . However, the material of the fixing portion 12 is not particularly limited as long as adjacent optical fibers can be fixed, and can be changed as appropriate.

As shown in FIG. 4A , in the optical fiber assembly 1 , a plurality of optical fiber units U and a plurality of intermittent fixed tape core wires 10 included in the optical fiber units U are periodically twisted. In this embodiment, a plurality of optical fiber units U and intermittently fixed tape core wires 10 are twisted into an SZ shape. In more detail, the optical fiber assembly 1 has an SZ twisted structure, and the aforementioned SZ twisted structure is such that the cycle 30 including the forward twisted portion 31 and the reverse twisted portion 32 repeats in the longitudinal direction Z. Period 30 is also referred to as twist pitch 30 . In each of the forward twisting part 31 and the reverse twisting part 32, a plurality of optical fiber units U and a plurality of intermittent fixed tape core wires 10 included in the optical fiber units U are twisted with each other. More specifically, in each of the forward-twisting section 31 and the reverse-twisting section 32 , each optical fiber unit U (intermittently fixed with a core wire 10 ) is wound around the central axis O of the optical fiber assembly 1 . As shown in FIG. 4A , the direction in which the optical fiber assembly 1 is twisted in the forward twist section 31 and the direction in which the optical fiber assembly 1 is twisted in the reverse twist section 32 are opposite to each other. In addition, in the forward twisting part 31 and the reverse twisting part 32, the twist angle (winding angle) of the inner layer unit Uin and the twist angle (winding angle) of the outer layer unit Uout may be equal or different.

Here, in this specification, in order to facilitate the following description, the inversion region 41 and the rotation region 42 are defined as shown in FIG. 4A for the optical fiber assembly 1 of the present embodiment. The reversed region 41 is a region extending in the longitudinal direction Z around the boundary B between the forward twisted portion 31 and the reversed twisted portion 32 . That is, the reverse region 41 is a region where the direction in which the intermittently fixed tape core wires 10 are twisted is reversed. Assume that the dimension of the period (twisting pitch) 30 is P, and the dimension in the longitudinal direction Z of the inversion region 41 is P/4. The rotation area 42 is an area other than the inversion area 41 . In other words, the rotation area 42 is an area located between the inversion areas 41 . The rotating area 42 is an area where the tape core wire 10 is intermittently fixed and twisted (wound) in one direction. In the optical fiber assembly 1 of the present embodiment, the inversion regions 41 and the rotation regions 42 alternately repeat in the longitudinal direction Z.

In addition, the configuration in which the optical fiber unit U and the intermittent fixed tape core wire 10 are periodically twisted is not limited to the above-mentioned SZ twisted structure. As shown in FIG. 4B , a plurality of optical fiber units U and a plurality of intermittent fixed tape core wires 10 may also be helically twisted. In other words, the optical fiber assembly 1 may have only one of the forward twisted portion 31 and the reverse twisted portion 32 . In this case, the period (twisting pitch) 30 is defined as a range in which a certain optical fiber unit U (intermittent fixed tape core 10) makes one turn around the central axis O of the optical fiber assembly 1 (see FIG. 4B ).

As shown in FIG. 5 , in the optical fiber assembly 1 of the present embodiment, a plurality of intermittently fixed tape core wires 10 are stacked in a state of being bent when viewed in cross section. In FIG. 5 , optical fibers 11 belonging to the same intermittent fixed tape core wire 10 are connected by solid wires. In addition, the "crimped state" refers to a state in which at least one intermittent fixed tape core wire 10 included in the optical fiber assembly 1 is bent. In addition, the shape of the laminated layers of intermittent fixed tape core wires 10 changes in the longitudinal direction Z of the optical fiber assembly 1 . In other words, the crimped state of the intermittent fixed tape core wire 10 changes in the longitudinal direction Z of the optical fiber assembly 1 . In other words, the cross-sectional shape of the optical fiber assembly 1 changes in the longitudinal direction Z of the optical fiber assembly 1 .

In this specification, vectors MG, GU, and scalar quantities LT, LU defined as follows are introduced in order to evaluate the crepe state of the intermittent fixed tape core wire 10 . Here, FIG. 6 is a diagram depicting a cross-sectional view of the optical fiber assembly 1 (optical fiber unit U) shown in FIG. 5 on the xy plane. In FIG. 6 , the six intermittent fixed tape core wires 10 included in the optical fiber unit U are referred to as a first tape to a sixth tape, respectively.

The vector MG is a vector quantity defined for each position in the longitudinal direction Z of the optical fiber assembly 1 for each intermittent fixed tape core 10 . In the cross section, M is the midpoint of the two optical fibers 11 located at both ends among the optical fibers 11 constituting the intermittently fixed tape 10 , and G is the center of gravity of the intermittently fixed tape 10 . As shown in FIG. 6 , the vector MG is a vector starting from the midpoint M and ending at the center of gravity G. In FIG. 6 , the vector MG defined for the first band is called vector MG1 , and the vector MG defined for the second band is called vector MG2 . The same applies to the 3rd to 6th bands. In addition, it is extremely rare that the midpoint M coincides with the center of gravity G in a state where the intermittent fixed tape core wire 10 has been crimped (bent).

The scalar LT is a scalar defined for each position in the longitudinal direction Z of the optical fiber assembly 1 for every intermittent fixed tape core wire 10 . The scalar LT is the magnitude of the vector MG. As can be seen from the above definition, the scalar amount LT is an amount that characterizes the creped state of the intermittent fixed tape core wire 10 . More specifically, it is considered that the intermittent fixed tape core wire 10 is more largely creped as the scalar amount LT is larger. This is because it can be considered that the greater the curvature of the intermittent fixed tape core wire 10 (the more creped the intermittent fixed tape core wire 10 ), the larger the scalar (magnitude) LT of the vector MG.

The vector GU is a vector quantity defined for each optical fiber unit U for each position in the longitudinal direction Z of the optical fiber assembly 1 . The vector GU is a vector obtained by synthesizing the vector MG for all the intermittent fixed tape cores 10 included in the optical fiber unit U (see FIG. 6 ).

The scalar LU is a scalar defined for each optical fiber unit U for each position in the longitudinal direction Z of the optical fiber assembly 1 . The scalar LU is the size of the vector GU. As can be seen from the above definition, the scalar quantity LU is a quantity that characterizes the crimped state of the optical fiber unit U. More specifically, it can be considered that the larger the scalar amount LU is, the more greatly the optical fiber unit U is bent. This is because it can be considered that the greater the bending of the intermittent fixed tape core wire 10 included in the optical fiber unit U (the more curved the intermittent fixed tape core wire 10), the larger the magnitude of the vector MG, and the vector GU after the vector MG is synthesized The scalar (size) of LU will also be larger. [Example]

Hereinafter, the above-mentioned embodiments will be described using specific examples. In addition, this invention is not limited to a following Example.

(Example) The 864-core optical fiber assembly and optical fiber cable of the above-mentioned embodiment were produced as the optical fiber assembly 1 and optical fiber cable 100 of the example. The optical fiber assembly 1 of the embodiment has 12 optical fiber units U twisted into an SZ shape. Each optical fiber unit U has six intermittently fixed ribbon cores 10 bundled by a bundle material 20 . Each intermittent fixed tape core wire 10 includes 12 optical fibers 11 . Also, at each position in the longitudinal direction Z, the twist angle (winding angle) of the inner layer unit Uin and the twist angle (winding angle) of the outer layer unit Uout are considered to be substantially equal to each other. The outer diameter of the outer covering 110 is set to 18.2mm, and the inner diameter of the outer covering 110 is set to 11.5mm. The thickness of the crimping member 120 is set to 0.2 mm. The outer diameter of the optical fiber assembly 1 is about 11.1 mm.

Table 1 and Table 2 are tables compiled of the results of measuring the scalar quantity LU for each position in the longitudinal direction Z of the optical fiber assembly 1 of the embodiment. More specifically, the measurement of the scalar LU is performed for the inversion region 41 and the rotation region 42 included in the four consecutive cycles (twisting pitch) 30 in the longitudinal direction Z. In addition, in Table 1 and Table 2, the nine inversion regions 41 are respectively referred to as a first inversion region to a ninth inversion region sequentially in the +Z direction. Similarly, the eight rotation areas 42 are respectively referred to as a first rotation area to an eighth rotation area. In addition, the 12 optical fiber units U are respectively referred to as a first unit to a twelfth unit, and are displayed with unit numbers 1 to 12. In addition, in the first rotation area, the first rotation area is subdivided into eight positions in the longitudinal direction Z, and the measurement of the scalar quantity LU is performed. In Table 1, these eight measurement positions are sequentially shown as the first rotation area (1/8) to the first rotation area (8/8) in the +Z direction. Similarly, in the second rotation area, the measurement of the scalar LU is performed by subdividing the second rotation area into five positions in the longitudinal direction Z. The five measurement positions are sequentially displayed in the +Z direction as the second rotation area (1/5) to the second rotation area (5/5).

[Table 1]

[Table 2]

"TOTAL" in Table 1 and Table 2 indicates the magnitude of a vector (vector GU) obtained by synthesizing vector MG for all intermittent fixed tape core wires 10 included in optical fiber assembly 1 . In addition, "maximum" displays the maximum value of the scalar LU in the first to twelfth cells for each area. Similarly, "Minimum" displays the minimum value of the scalar LU in the first to twelfth cells for each area. "Difference" is a value obtained by subtracting the minimum value from the above-mentioned maximum value for each area. In addition, "average" indicates the average value of the scalar amount LU in the entire area to be measured for each optical fiber unit U.

FIG. 7 is a diagram showing Table 1 and Table 2 as a graph. In FIG. 7 , the four cycles 30 which are measurement objects are referred to as the first cycle to the fourth cycle in order in the +Z direction. In addition, in FIG. 7 , the scalar LU in the first rotation region (5/8) is used as a representative value, and is used as the scalar LU in the first rotation region. Similarly, the scalar LU in the second rotation region (3/5) is used as a representative value as the scalar LU in the second rotation region. However, the first rotation area (5/8) is considered to be located approximately in the center of the longitudinal direction Z of the first rotation area, and the second rotation area (3/5) is considered to be located on the long side of the second rotation area. Approximate central position in direction Z. FIG. 8 is a graph showing the results of measuring the scalar amount LU for only the inversion region 41 , that is, the first to ninth inversion regions). FIG. 9 is a measurement of the scalar value only for the rotation region 42 between the first rotation region and the second rotation region, that is, the first rotation region (1/8) to the first rotation region (8/8). The results of LU are displayed as a plot of the graph.

In addition, the measurement of the scalar LU at each position is performed by photographing the cross-section of the optical fiber assembly 1 at regular intervals in the longitudinal direction Z, and taking images obtained by the photographs on the xy plane. The image is traced. More specifically, the measurement of the scalar LU is performed in the following procedure. That is, light is incident on a predetermined optical fiber 11 with a cored wire 10 (optical fiber unit U) intermittently fixed, and how the optical fiber unit U including the optical fiber 11 propagating the incident light is twisted, thereby confirming that each intermittently fixed cored wire The winding angle of 10 (optical fiber unit U) is used to distinguish the inversion area 41 and the rotation area 42 . Thereafter, the optical fiber assembly 1 is fixed with epoxy resin, and cut at each position in the longitudinal direction Z. After polishing the fixed optical fiber assembly 1 to make the cross-section clear, an image of the cross-section was photographed with a microscope. On the image obtained by the microscope, the position of each optical fiber 11 is plotted on the xy plane, and the scalar amount LU is measured. In addition, after fixing the optical fiber assembly 1 with epoxy resin, the optical fiber cable 100 may be cut at each position in the longitudinal direction Z. In this case, for example, the epoxy resin may be injected from one end in the longitudinal direction Z of the optical fiber cable 100, and the epoxy resin may be sucked from the other end, thereby filling the outer jacket with the epoxy resin. within 110 pieces.

As can be seen from FIG. 7 , in each of the first period to the fourth period of the optical fiber assembly 1 of the embodiment, there is at least one group of optical fiber units U in which the magnitude relationship of the scalar LU is reversed. In other words, as shown in FIG. 7 , when the transition in the longitudinal direction Z of the scalar LU of each unit is represented by a plurality of broken lines, there is at least one intersection point where two broken lines intersect in each period.

More specifically, an example will be given and described. For example, from Figure 7 and Table 1, in the first cycle, ・In unit 1, the scalar LU in the 1st inversion area is 0.7, the scalar LU in the 1st rotation area (5/8) is 0.3, ・In unit 2, the scalar LU in the 1st inversion area is 0.3, and the scalar LU in the 1st rotation area (5/8) is 0.4. In this way, between the first inversion area and the first rotation area in the first cycle, the magnitude relationship of the scalar LU of the first unit and the second unit is reversed, and there are the first unit and the second unit in FIG. 7 The intersection point where the 2 polylines of the cell intersect. In the above description, only the example in which the broken lines intersect between the first inversion area and the first rotation area in the first unit and the second unit was described, but in FIG. intersection point. Furthermore, when the transition in the longitudinal direction Z of the scalar LU of each unit is represented by a plurality of broken lines, at least one intersection point where two broken lines intersect exists in each period.

Furthermore, it can be seen that since the above relationship holds for the scalar quantity LU of the optical fiber unit U, the same relationship holds true mathematically for the scalar quantity LT of the intermittently fixed tape core 10 . That is, in each of the first period to the fourth period of the optical fiber assembly 1 , at least one set of intermittent fixed tape core wires 10 exists in which the magnitude relationship of the scalar LT is reversed. More specifically, as described above, the vector GU is a vector obtained by synthesizing the vector MG for all the intermittent fixed tape cores 10 included in the optical fiber unit U. The size of the vector GU is the scalar LU, and the size of the vector MG is the scalar LT. Between the first inversion region and the first rotation region of the first cycle, the magnitude relationship of the scalar LU of the first unit and the second unit will be reversed. In this case, it can be known mathematically that the first Inversion of the magnitude relationship between the scalar amount LT of any one of the intermittent fixed tape core wires 10 included in the first unit and the scalar amount LT of any one of the intermittent fixed tape core wires 10 included in the second unit occurs similarly.

To be more specific using an example from above, (1) In the first reverse region, "the scalar LU of the first unit > the scalar LU of the second unit", (2) In the first rotation region, "the scalar LU of the first unit<the scalar LU of the second unit". In this case, it can be clearly seen that the specific one intermittent fixed belt core wire included in the first unit is set as the first belt, and the specific one intermittent fixed belt core wire included in the second unit is set as the first belt. For the 2nd band, (1') In the first inversion region, when "the scalar LT of the first band included in the first unit > the scalar LT of the second band included in the second unit", (2') In the first rotation area, there will be at least one set of intermittent fixation where "the scalar LT of the first band included in the first unit < the scalar LT of the second band included in the second unit" holds With core wire. As such, in this embodiment, in each of the twisting cycles, there is at least one set of intermittent fixed belt core wires (including the first belt and the second belt in the above description) in which the magnitude relationship of the scalar LT is reversed. 1 set of intermittent fixed belt core wires).

Also, from Figure 7 and Table 1, in the fourth cycle, ・The scalar LU in the 7th inversion area, the 7th inversion area, the 8th inversion area, and the 8th inversion area of unit 9 are 0.4, 0.4, 0.2, 0.3, respectively, ・The scalar LU in the 7th inversion area, the 7th rotation area, the 8th inversion area, and the 8th rotation area of the 12th unit were 0.7, 0.9, 0.6, and 0.6, respectively. Here, the third cycle is defined as a cycle that includes a region in the longitudinal direction Z that includes the position where the measurement of the scalar LU in the fifth inversion region is performed, and that is on the +Z side of the position. area, the fifth rotation area, the sixth inversion area, the sixth rotation area, and the area on the -Z side from the position where the scalar LU was measured in the seventh inversion area. The fourth period is defined as a period including the area on the +Z side of the boundary B at the position where the measurement of the scalar LU of the seventh inversion area was performed in the longitudinal direction Z, the area on the The 7th rotation area, the 8th inversion area, the 8th rotation area, and the area on the −Z side from the position where the measurement of the scalar LU in the 9th inversion area was performed.

In the seventh inversion region, the seventh rotation region, the eighth inversion region, and the eighth rotation region in the fourth cycle, the scalar quantity LU of the 12th unit is larger than that of the ninth unit. Also, the scalar LU in the 9th inversion region of the 9th unit is 0.2, the scalar LU in the 9th inversion region of the 12th unit is 0.4, and in the 9th inversion region, the scalar LU in the 4th cycle The magnitude relationship of is not reversed. That is, as shown in FIG. 7 , the broken lines corresponding to the ninth unit and the twelfth unit do not cross each other in the fourth cycle. From this, it can be said that in the fourth cycle, the size relationship of the scalar LU of the ninth unit and the twelfth unit is not reversed.

In the 6th rotation area of the 3rd cycle, ・The scalar LU of Unit 9 is 0.2, ・The scalar LU of the 12th unit is 0.1. That is to say, in the 6th rotation area of the 3rd cycle, the scalar LU of the 12th unit will be smaller than the scalar LU of the 9th unit, compared with the 4th cycle, the magnitude relationship of the scalar LU is reversed of. Accordingly, as shown in FIG. 7 , in the third cycle, the broken lines corresponding to the two cells intersect each other. Like this, in one of the twisting cycles, that is, the Xth cycle (X is an arbitrary integer. In the above description, it is the fourth cycle), although at least one group of optical fiber units U (the ninth unit and the twelfth unit) The magnitude relationship of the scalar LUs will not be reversed, but in periods other than the X period (for example, the 3rd period), the magnitude relationship of the scalar LUs will be reversed.

Also, as can be seen from FIG. 8, in each of the first inversion region to the ninth inversion region of the optical fiber assembly 1 of the embodiment, there is at least one group of optical fiber units in which the magnitude relationship of the scalar LU is reversed. U. More specifically, among the first to ninth inversion regions, between two inversion regions 41 adjacent in the longitudinal direction Z, at least one of the magnitude relationships of the scalar LU is reversed. Group fiber unit U.

Also, as can be seen from FIG. 9, in each of the first rotation area (1/8) to the first rotation area (8/8) of the optical fiber assembly 1 of the embodiment, there is a scalar LU of the magnitude At least one group of optical fiber units U whose relationship is reversed. More specifically, in the first rotation area (1/8) to the first rotation area (8/8), there is a scalar LU between two adjacent areas in the longitudinal direction Z. At least one group of optical fiber units U whose relationship is reversed. That is, in the optical fiber assembly 1 of the embodiment, in one rotating region 42, there is at least one group of optical fiber units U in which the magnitude relationship of the scalar LU is reversed. In other words, there is at least one group of optical fiber units U in which the magnitude relationship of the scalar LU is reversed in the section not including the inversion region 41 but only the rotation region 42 .

In addition, in order to change the crepe state of the intermittent fixed tape core wire 10 so that the above-mentioned relationship with the scalar quantities LT, LU, and the vectors MG and GU holds true, in the manufacturing process of the optical fiber assembly 1, for example, the following technique. The first method is a method of temporally changing the tension applied to the optical fiber unit U and the intermittent fixed tape core wire 10 during twisting the optical fiber unit U and the intermittent fixed tape core wire 10 into an SZ shape. The second method is a method of temporally changing the rotation speed of a clamp used when twisting the optical fiber unit U and the intermittent fixed tape core wire 10 into an SZ shape. The third technique is to vary the distance between each through hole and the center of the clamp for the plurality of through holes formed in the clamp and through which the optical fiber unit U and the intermittently fixed tape core 10 are respectively inserted. The fourth method is a method of making the shapes or sizes of the through holes different for the above-mentioned plurality of through holes. The fifth method is a method of adjusting the time length of the temporary stop (rotation of the above-mentioned clamps) when the direction of twisting is reversed. The sixth method is a method of arranging optical fiber units U having different numbers of cores adjacent to each other. In addition, the first method to the sixth method described above are merely examples, and other methods may be used as long as the optical fiber assembly 1 in which the above-mentioned relationship regarding the scalars LT, LU, vectors MG, and GU is satisfied can be manufactured. In addition, some methods among the above-mentioned methods may be used in combination.

Next, the action of the optical fiber assembly 1 configured as above will be described.

Conventionally, an optical fiber cable (optical fiber assembly) having a plurality of optical fiber units collectively covered with a sheath is known. In such an optical fiber cable, when bending occurs or the sheath shrinks in a low-temperature environment, strain may concentrate on specific intermittent fixed ribbon core wires or optical fibers. Such concentration of strain may increase the maximum transmission loss of the optical fiber cable (optical fiber assembly). Also, as mentioned above, when the strain concentration of a specific intermittently fixed tape core (optical fiber) is present, when the cross-sectional shape of the optical fiber cable (optical fiber assembly), that is, the crimped state of the optical fiber unit (intermittently fixed tape core) is in a relatively long interval For fixed cases, it is especially easy to generate. In other words, strain concentration on a specific intermittent fixed tape core wire is particularly likely to occur when the same crimped state continues over a long section.

On the other hand, in the optical fiber assembly 1 of the present embodiment, at least one set of intermittently fixed cored wires 10 in which the magnitude relationship of the scalar LT is reversed exists for each twisting period (twisting pitch) 30 . That is, the cross-sectional shape of the optical fiber assembly 1 , that is, the crimped state of the intermittent fixed tape core wire 10 changes in each twisting cycle 30 . Therefore, the crimped state of the intermittently fixed tape core wire 10 is not easily fixed in the longitudinal direction Z, and the concentration of strain on a specific intermittently fixed tape core wire 10 or the optical fiber 11 can be suppressed. Thereby, an increase in the maximum transmission loss of the optical fiber assembly 1 can be suppressed.

As described above, the optical fiber assembly 1 of the present embodiment includes a plurality of intermittently fixed tape core wires 10, the plurality of intermittently fixed tape core wires 10 include a plurality of optical fibers 11 and a plurality of optical fibers 11 intermittently fixed in the longitudinal direction Z. A fixed portion 12, a plurality of intermittently fixed core wires 10 are periodically twisted, in the cross section, one of the plurality of intermittently fixed core wires 10 is intermittently fixed with two optical fibers 11 located at both ends of the core wire 10 Set the midpoint of M as M, set the center of gravity as G, set the vector starting from the midpoint M and ending at the center of gravity G as MG, and set the magnitude of the vector MG as the scalar LT, in the aforementioned twisting period In each of 30, there is at least one set of intermittently fixed tape core wires 10 in which the magnitude relationship of the scalar LT is reversed.

According to this configuration, it is possible to suppress the concentration of strain on a specific intermittent fixed tape core wire 10 or optical fiber 11 , and to suppress an increase in the maximum transmission loss of the optical fiber assembly 1 .

Also, a plurality of intermittently fixed tape core wires 10 form a plurality of optical fiber units U, and in each of the plurality of optical fiber units U, at least two or more intermittently fixed tape core wires 10 among the plurality of intermittently fixed tape core wires 10 can also be bundled. bundle. According to this configuration, it is possible to suppress the concentration of strain on a specific optical fiber unit U, and to suppress an increase in the maximum transmission loss of the optical fiber assembly 1 .

Also, when a vector MG obtained by synthesizing a vector MG for all of the plurality of intermittent fixed tape core wires 10 included in one optical fiber unit U among the plurality of optical fiber units U is denoted as GU, and the magnitude of the vector GU is denoted as a scalar LU, In each of the aforementioned twisting periods 30, there may also be at least one group of optical fiber units U in which the magnitude relationship of the scalar LU is reversed. According to this configuration, the concentration of strain on the specific optical fiber unit U can be more reliably suppressed, and the increase in the maximum transmission loss of the optical fiber assembly 1 can be more reliably suppressed.

Also, when a vector MG obtained by synthesizing a vector MG for all of the plurality of intermittent fixed tape core wires 10 included in one optical fiber unit U among the plurality of optical fiber units U is denoted as GU, and the magnitude of the vector GU is denoted as a scalar LU, In one of the twisting cycles 30, that is, in the Xth cycle, there may also be at least one group of aforementioned optical fiber units U whose magnitude relationship of the scalar LU is not adjusted, and this group of aforementioned optical fiber units U is in the twisting cycle 30. In periods 30 other than the Xth period of , the size relationship of the scalar LU is reversed. According to this configuration, the concentration of strain on the specific optical fiber unit U can be more reliably suppressed, and the increase in the maximum transmission loss of the optical fiber assembly 1 can be more reliably suppressed.

Also, the aforementioned twisting cycle 30 may also include: forward twisting part 31, a plurality of intermittent fixed belt core wires 10 are twisted together; direction of twisting. In other words, a plurality of intermittent fixed tape core wires 10 can also be twisted into an SZ shape. According to this configuration, the concentration of strain on the specific optical fiber unit U can be more reliably suppressed, and the increase in the maximum transmission loss of the optical fiber assembly 1 can be more reliably suppressed.

Moreover, the optical fiber cable 100 of this embodiment is provided with the said optical fiber assembly 1, and the outer covering material 110 which accommodates the optical fiber assembly 1. As shown in FIG. According to this configuration, an increase in the maximum transmission loss of the optical fiber cable 100 can be suppressed.

Also, the manufacturing method of the optical fiber assembly 1 of the present embodiment is to combine a plurality of optical fiber assemblies 1 in such a manner that at least one group of intermittently fixed cored wires 10 in which the magnitude relationship of the scalar LT is reversed exists in each of the twisting cycles 30. The intermittent fixed tape core wire 10 is periodically twisted. According to this configuration, it is possible to manufacture the optical fiber assembly 1 in which the increase in the maximum transmission loss is suppressed.

In addition, the technical scope of this invention is not limited to the said embodiment, Various changes can be added in the range which does not deviate from the summary of this invention.

For example, the optical fiber assembly 1 may have inclusions (not shown) such as PP yarns or water-absorbent polymers. The inclusions can also be arranged between adjacent optical fiber units U, or between adjacent intermittent fixed tape core wires 10 . In the case where the optical fiber assembly 1 has the aforementioned inclusions, it becomes easier to bend the shape of the optical fiber assembly 1 . Accordingly, it is possible to more reliably suppress an increase in the maximum transmission loss of the optical fiber assembly 1 .

In addition, the number of optical fiber units U included in the optical fiber assembly 1 may be 11 or less, or may be 13 or more. In addition, the number of intermittent fixed tape core wires 10 included in each optical fiber unit U may be 2 or more and 5 or less, or may be 7 or more. In addition, the number of optical fibers 11 contained in each intermittent fixed tape core wire 10 may be 2 or more and 11 or less, or may be 13 or more.

Also, in any one cycle 30 or in all the cycles 30, there may not be a group of optical fiber units U in which the magnitude relationship of the scalar LU is reversed.

In addition, the configurations other than the optical fiber assembly 1 such as the sheath 110, the crimping member 120, the tensile member 130, and the tear cord 140 in the above-mentioned embodiment are all examples and can be changed as appropriate. For example, the optical fiber assembly 1 of this embodiment can also be applied to a loose tube cable or the like. In addition, the above-mentioned configurations other than the optical fiber assembly 1 may not be required. That is, the optical fiber assembly 1 may not constitute the optical fiber cable 100 .

Also, when the optical fiber unit U and the intermittent fixed tape core wire 10 are twisted in an SZ twisting structure, in the forward twisting part 31 and the reverse twisting part 32, the twist angle (winding angle) of the inner layer unit Uin is the same as that of the inner layer unit Uin. The twist angle (winding angle) of the outer unit Uout can also be equal, the cycle (twisting pitch) of the inner layer unit Uin and the cycle (twisting pitch) of the outer layer unit Uout can also be equal, the inner layer unit Uin and the outer layer unit Uout The position of the boundary B between the forward-twisting portion 31 and the reverse-twisting portion 32 in the longitudinal direction Z may be the same. In addition, it is not limited to this configuration, for example, the twist angle, the twist pitch, or the position of the boundary B may be different between the inner unit Uin and the outer unit Uout.

In addition, the optical fiber assembly 1 may not have the bundle material 20, but may be formed by twisting a plurality of intermittent fixed tape core wires 10 into an SZ shape. In other words, the intermittent fixed tape core wire 10 may not form the optical fiber unit U. Even with this configuration, at least one set of intermittent fixed tape core wires 10 in which the magnitude relationship of the scalar LT is reversed exists in each of the twisting cycles 30, so that strain concentration on a specific intermittent fixed tape core wire 10 can be suppressed. Or in the case of the optical fiber 11, an increase in the maximum transmission loss of the optical fiber assembly 1 can be suppressed.

In addition, without departing from the gist of the present invention, the constituent elements in the above-described embodiments may be appropriately replaced with known constituent elements, and the above-described embodiments or modified examples may be appropriately combined.

1: Optical fiber assembly 10: Intermittent fixed belt core wire 11: Optical fiber 12: Fixed part 20: bundle material 30: twist pitch (period) 31: Twisting part 32: reverse twisting part 41: Reverse area 42: Rotation area 100: fiber optic cable 110: Outer quilt 110a: protrusion 120: roll pressing 130: Tension body 140: Rip Rope B: Boundary G: center of gravity LT, LU: scalar (size) M: Midpoint MG,MG1,MG2,MG3,MG4,MG5,MG6,GU: vector O: central axis P,P/4: size U: Optical fiber unit Uin: inner unit Uout: outer unit W: Belt width direction Z: Long side direction +Z, -Z: direction

Fig. 1 is a cross-sectional view showing an optical fiber assembly and an optical fiber cable according to an embodiment of the present invention. Fig. 2 is a perspective view showing an optical fiber unit according to an embodiment of the present invention. Fig. 3 is a perspective view showing an intermittently fixed tape core wire according to an embodiment of the present invention. Fig. 4A is a diagram illustrating an SZ twist structure according to an embodiment of the present invention. Fig. 4B is a diagram illustrating a helical twist structure according to an embodiment of the present invention. Fig. 5 is a cross-sectional view showing an optical fiber unit according to an embodiment of the present invention. Fig. 6 is a diagram illustrating vectors MG, GU. Fig. 7 is a diagram showing transition of scalar LU for an optical fiber assembly according to an embodiment of the present invention. Fig. 8 is a graph showing the transition of the scalar LU in the inversion region for the optical fiber assembly according to the embodiment of the present invention. Fig. 9 is a graph showing the transition of the scalar LU in the swivel region for the optical fiber assembly according to the embodiment of the present invention.

Claims (7)

An optical fiber assembly comprising a plurality of intermittently fixed ribbon cores, the plurality of intermittently fixed ribbon cores including a plurality of optical fibers and a plurality of fixing parts intermittently fixing the plurality of optical fibers in the longitudinal direction, The plurality of intermittent fixed belt core wires are periodically twisted, In a section perpendicular to the aforementioned long-side direction, Assuming that the midpoint of the two aforementioned optical fibers located at both ends of one of the aforementioned plurality of intermittent fixed-band core wires is M, and the center of gravity is G, the aforementioned midpoint M will be used as the starting point and the aforementioned center of gravity will be The vector with G as the end point is set to MG, and when the size of the aforementioned vector MG is set to the scalar LT, In each of the twisting cycles, at least one set of the intermittent fixed tape core wires in which the magnitude relationship of the scalar LT is reversed exists. The optical fiber assembly as claimed in item 1, wherein the aforementioned plurality of intermittent fixed ribbon core wires form a plurality of optical fiber units, In each of the plurality of optical fiber units, at least two or more of the intermittent fixed tape core wires among the plurality of intermittent fixed tape core wires are bundled. An optical fiber aggregate as claimed in claim 2, wherein the vector MG synthesized for all of the plurality of intermittent fixed tape cores contained in one of the aforementioned optical fiber units is set to GU, and the aforementioned vector is When the size of GU is set to scalar LU, In each of the twisting cycles, at least one group of the optical fiber units in which the magnitude relationship of the scalar LU is reversed exists. An optical fiber assembly as claimed in claim 2 or 3, wherein the vector MG synthesized for all of the aforementioned plurality of intermittent fixed tape cores included in one of the aforementioned plurality of optical fiber units is set to GU, and When the size of the aforementioned vector GU is set to the scalar LU, In one of the aforementioned twisting cycles, that is, in the Xth cycle, there is at least one group of the aforementioned optical fiber units in which the size relationship of the aforementioned scalar LU is not adjusted, In the period other than the X-th period among the twisting periods of the aforementioned group of optical fiber units, the magnitude relationship of the aforementioned scalar LU is reversed. The optical fiber assembly according to any one of Claims 1 to 4, wherein the twisting period includes respectively: a forward twisting part, the aforementioned plurality of intermittently fixed core wires are twisted; and a reverse twisting part, the aforementioned plurality of intermittently fixed The cored wire is twisted in the opposite direction to that of the aforementioned forward twist. A fiber optic cable having: An optical fiber assembly according to any one of Claims 1 to 5; and The outer jacket accommodates the aforementioned optical fiber assembly. A method for manufacturing an optical fiber assembly, which is a method for manufacturing an optical fiber assembly, wherein the optical fiber assembly includes a plurality of intermittently fixed tape cores, the plurality of intermittently fixed tape cores include a plurality of optical fibers and a plurality of fixing parts intermittently fixing the aforementioned plurality of optical fibers, In a section perpendicular to the aforementioned long-side direction, Assuming that the midpoint of the two aforementioned optical fibers located at both ends of one of the aforementioned plurality of intermittent fixed-band core wires is M, and the center of gravity is G, the aforementioned midpoint M will be used as the starting point and the aforementioned center of gravity will be The vector with G as the end point is set to MG, and when the size of the aforementioned vector MG is set to the scalar LT, The plurality of intermittent fixed tape core wires are periodically twisted so that at least one group of the intermittent fixed tape core wires in which the scalar LT is reversed exists in each twisting cycle.

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