JP5846758B2 - Optical fiber cable and optical fiber cable branching method - Google Patents

Description

  The present invention relates to an optical fiber cable excellent in branching workability and a method for branching an optical fiber cable.

  Conventionally, an optical fiber cable in which an optical fiber core wire is covered with a jacket is used. In use, such an optical fiber cable is branched and wired to a plurality of houses.

  As such an optical fiber cable, for example, a slot type optical fiber that uses a slot rod in which a plurality of grooves capable of installing a plurality of optical tape cores are formed on the outer periphery, and a tension member is arranged at the center of the slot rod. There is a cable (Patent Document 1).

  There is also a loose type optical fiber cable in which a plurality of loose tubes containing a plurality of optical fiber cores are arranged and a tension member is arranged in the center (Patent Document 2).

JP-A-8-262294 JP 2009-86637 A

  However, when the inner optical fiber core is branched with respect to the conventional optical fiber cable having a substantially circular cross section, it is necessary to remove the outer sheath. For removing the sheath, a nipper, a cutter, or the like is used, but the operation is dangerous and the inner core wire may be damaged.

  On the other hand, as a tool for removing the sheath of the optical fiber cable having a substantially circular cross-sectional shape, there is a tool for cutting the sheath by inserting a blade into the sheath at a predetermined depth in the circumferential direction from the outer periphery (for example, “Fine” manufactured by Furukawa Electric Co., Ltd.). “Sheath stripper” (hereinafter simply referred to as “sheath stripper”). By setting such a sheath stripper on the outer periphery of the optical fiber cable and making the outer periphery of the optical fiber cable make one round in the circumferential direction, a circumferential cut can be made in the sheath. Therefore, the work is safe.

  However, when a jig such as a “Fine sheath stripper” is used for a cable having a tension member at the center as shown in Patent Documents 1 and 2, it is difficult to know the cutting allowance of the blade. Further, when a tension member or the like is arranged in a part of the sheath cross section (central core cable), it is not possible to make a cut in the circumferential direction. For this reason, when taking out an optical fiber core wire from the inside, it is necessary to use the above-mentioned nipper, cutter, etc.

  The present invention has been made in view of such problems, and an object thereof is to provide an optical fiber cable or the like that can be easily branched.

In a cross section of an optical fiber cable comprising an optical fiber core, a protective layer for protecting the optical fiber core, and a sheath formed on the outer periphery of the protective layer, a tension member is embedded in the protective layer. The protective layer has a continuous division in the longitudinal direction, and the protective layer can be divided into a plurality of sections in the cross section, and the divided sections are formed in at least two places in the cross section, and any two places the divided portion is not parallel to one another, an optical fiber cable which is formed at an angle, the extension line of the inner periphery side end portion of the protective layer of the divided portion of the arbitrary two points in the cross section is light in the direction not suited to the center of the fiber cable is a fiber optic cable, wherein the chevron of one by the extension line of the divided portions of the arbitrary two points are formed

The two arbitrary divided portions divide the protective layer into a first divided piece and a second divided piece smaller than the first divided piece, and the divided portions are formed in a straight line in a cross section. It is desirable that Moreover, an uneven shape may be formed in a cross section in the divided portion, and the divided pieces of the respective protective layers that are divided into a plurality of pieces may be engaged with each other in the uneven shape.

  Each of the divided pieces of the protective layer divided into a plurality of pieces may be divided into a divided piece provided with a tension member and a divided piece provided with no tension member.

  The protective layer is preferably made of a resin having a melting point higher than that of the resin constituting the sheath. A peeling member may be provided between the protective layer and the sheath.

  A resin tape having a melting point equal to or lower than the melting point of the resin constituting the sheath may be wound around the outer periphery of the protective layer, and the resin tape and the sheath may be fused and integrated. The optical fiber core wire may be held by a holding member inside the protective layer.

  According to the first invention, since the tension member is embedded in the protective layer, even if the sheath stripper is used for cutting from the outer periphery, only the depth of the tension member is cut from the outer surface of the sheath in the circumferential direction. The optical fiber core wire inside the protective layer is not damaged. Further, since the protective layer is divided into a plurality of sections in the cross section, the inner optical fiber can be easily taken out from the divided portion of the protective layer by peeling off the outer sheath.

  In particular, when the concavo-convex shape is formed in the divided portion and these mesh with each other, even when the optical fiber cable is bent, a deviation between the divided portions can be prevented. It can prevent mouth opening. Therefore, an inner optical fiber core or the like is not caught between the divided portions.

  In addition, a split member that is not provided with a tension member can be easily deformed by providing a tension member on a part of the split piece that is divided into a plurality and a tension member not provided on the other. It is also possible to partly cut off this segment. Therefore, it is excellent in the take-out property of the optical fiber core wire.

  If the melting point of the resin constituting the protective layer is higher than the sheath melting point, the sheath and the protective layer are not fused at the time of sheath sheath extrusion, and the sheath can be easily peeled off. Further, by providing a peeling member such as a resin film between the protective layer and the sheath, the sheath and the protective layer can be easily peeled off.

  Further, since the resin tape is provided on the outer periphery of the protective layer, the protective layer is pressed by the resin tape at the time of manufacturing the optical fiber cable, and the divided pieces are not separated. Moreover, since the resin tape is fused to the sheath, the dismantling workability is excellent.

  Moreover, it can prevent that an optical fiber core wire is pinched | interposed into a division | segmentation part by providing a holding member in the inside of a protective layer.

A second invention uses the optical fiber cable according to the first invention, and makes a cut from the outer peripheral side of the optical fiber cable to the depth where the tip of the blade contacts the tension member in the circumferential direction of the sheath. as a depth substantially the same depth of cut, the sheath by the add cut along the longitudinal direction of the optical fiber, to expose the protective layer, to divide the protective layer by the division unit, the dividing unit A branching method for an optical fiber cable, wherein an internal optical fiber core wire is taken out and branched.

  After taking out the optical fiber core, a hole through which the branched optical fiber core can be penetrated is formed in the protective layer, and the branched optical fiber core is branched to the outside through the hole, and then the entire branch portion May be waterproofed.

  According to the second invention, since the blade does not enter the inner side of the protective layer, the inner optical fiber core wire is not damaged by the blade and can be easily branched. Moreover, the taken-out optical fiber core wire can be branched reliably.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where a tension member etc. are embed | buried in a protective layer, the optical fiber cable etc. which can be branched easily can be provided.

1 is a cross-sectional view of an optical fiber cable 1. FIG. The figure which shows the state which put the blade 19 in the optical fiber cable 1. FIG. The figure which shows the optical fiber cable 1 provided with the notches 21a and 21b. The figure which shows the state which divided | segmented the division part 12. FIG. The figure which shows the state which provided the hole 23 in the protective layer 11 and took out the branched optical fiber 3a. The figure which shows the state which provided the wiring member 25 in the protective layer 11, and took out the branched optical fiber 3a. (A) is the figure which shows the state which wound the resin tape 27 around the outer periphery of the protective layer 11, (b) is the figure which shows the state which coat | covered the sheath 7 on the protective layer 11, (c) removes a part of sheath FIG. (A) is sectional drawing of the optical fiber cable 1a, (b) is sectional drawing of the optical fiber cable 1b. (A) is sectional drawing of the optical fiber cable 1c, (b) is sectional drawing of the optical fiber cable 1d. (A) is sectional drawing of the optical fiber cable 1e, (b) is sectional drawing of the optical fiber cable 1f. The figure which shows other embodiment of the site | part of the notch | incision 21b.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the optical fiber cable 1. The optical fiber cable 1 includes an optical fiber core wire 3, an optical fiber holding part 5, a sheath 7, a tension member 9, a protective layer 11, and the like.

  A plurality of optical fiber core wires 3 are arranged at a substantially central position of the cross section of the optical fiber cable 1. The optical fiber core wire 3 may be a single core fiber, a unit in which single fiber fibers are bundled, or a tape core wire. In addition, when an optical fiber core such as a single core fiber or a tape core is placed inside a protective layer, which will be described later, the entire optical fiber core is further vertically extended by a film or a tape member (tape-like material such as nonwoven fabric or PET). You may wind up and integrate. In addition, the optical fiber core wire 3 may be fixed with a UV material or the like at a predetermined interval, water-absorbing interposition or water-absorbing powder may be mixed, and the tape member itself is a water-absorbing tape member You can also.

  An optical fiber holding part 5 is provided on the outer periphery of the optical fiber core 3 as necessary. The optical fiber holding portion 5 is a portion that is made of a fiber such as polypropylene yarn, UV resin, or the like and holds the optical fiber core wire 3. In addition, the optical fiber holding | maintenance part 5 is only arrange | positioned only at the outer periphery of the optical fiber core wire 3, and can be removed easily.

A protective layer 11 is provided on the outer periphery of the optical fiber holding unit 5. The protective layer 11 is made of a resin such as high density polyethylene, for example. The protective layer 11 is divided into a plurality of pieces (two pieces of divided pieces 11 a and 11 b in the drawing), and has a substantially cylindrical shape in a state where the divided pieces are combined in the divided portion 12. In addition, the division | segmentation piece 11b is small with respect to the division | segmentation piece 11a (about 1/3 of the whole in the cross section of the protective layer 11). Further, in the cross section, the divided portions 12 formed at two places are not parallel to each other but formed at an angle. That is, the division part 12 is not formed on one straight line but is configured at different angles (positions). By doing in this way, when the force is applied from the outside, it can prevent that the division | segmentation part 12 deform | transforms in the opening direction. Therefore, the internal fiber is not caught between the open portions of the divided pieces.
On the other hand, if the dividing portion 12 is formed on a straight line (if formed in parallel), when a force is applied in the linear direction, the dividing piece is deformed (or shifted) in the direction in which the dividing portion opens. There is a fear. Therefore, it is desirable that the division parts 12 have an angle rather than being parallel to each other.
In addition, as shown in FIG. 1, it is desirable for the dividing part 12 to have an angle in a mountain shape (a direction in which the extending direction of the dividing part in the cross section does not face the center direction of the cable). For example, when a load is applied in the left-right direction or the up-down direction in FIG. 1, the opening of the split piece 11a is deformed in a direction to close inward. For this reason, it is hard to produce a clearance gap in the division part 12. On the other hand, when the split part 12 is formed at an angle in the opposite direction (when the split part is formed radially from the center of the cable), one split piece is pushed into the interior when receiving a load. The split piece deforms in the direction. Therefore, as shown in the drawing, the dividing portion 12 is preferably formed in a mountain shape.

  A tension member 9 is embedded in the protective layer 11 (one divided piece 11a). That is, the tension member 9 is not provided on the other divided piece 11b. Therefore, it can be divided into a divided piece in which the tension member 9 is provided and a divided piece not provided in the plurality of divided pieces. The tension member 9 is a part responsible for the tension of the optical fiber cable 1. As the tension member 9, for example, a fiber reinforced plastic made of steel wire, monofilament, aramid fiber or the like can be used. The tension member 9 is a member that is sufficiently hard with respect to the protective layer 11 and the sheath 7.

  A sheath 7 is provided on the outer periphery of the protective layer 11. As the sheath 7, for example, a resin such as polyethylene can be used. A mark portion 13 is provided on the outer surface corresponding to the tension member 9 of the sheath 7. The mark part 13 is formed of colored resin, for example. The mark portion 13 may be formed as a concave portion or a convex portion as long as the position of the tension member 9 can be determined from the outer periphery.

  Next, a branching method using the optical fiber cable 1 according to the present invention will be described. First, as shown in FIG. 2, the tool 17 cuts the outer periphery of the optical fiber cable 1. As the tool 17, the above-described sheath stripper can be used. In other words, the tool 17 is capable of adjusting the allowance of the blade 19 and easily responds to the allowance of the blade in the circumferential direction with respect to the outer periphery of the sheath 7 while maintaining the allowance of the blade of a predetermined amount. A depth cut can be made.

  FIG. 2 shows an example in which an incision of a predetermined depth (B) is made in the sheath 7 by making the outer margin of the blade 19 one turn around the outer periphery of the sheath 7 (in the direction of arrow A in the figure). The depth of cut is set as follows. First, the blade 19 is slightly protruded from the tool 17 and a cut is made in the outer periphery of the sheath 7. When the cut is made with respect to the entire circumference, the blade 19 is further extended to make a cut into the entire circumference of the sheath 7 again. The above operation is repeated until the tip of the blade 19 contacts the tension member 9.

  Since the position of the tension member 9 can be visually recognized from the outside by the mark portion 13, after adjusting the protrusion of the blade so that the tip of the blade 19 contacts the tension member 9 at the position of the mark portion 13, Cuts may be made over the circumference. In any case, when the tip of the blade 19 comes into contact with the tension member 9, the blade 19 does not enter deeper than that. For this reason, the cutting depth B is approximately the arrangement depth of the tension member 9.

  FIG. 3 is a view showing a state in which a circumferential cut 21a is made on the outer periphery of the sheath 7 by the above-described method. For example, the cuts 21a may be provided at two positions on both ends of the range where the branching operation is performed.

  Next, as shown in the figure, a cut 21 b is provided in the longitudinal direction of the optical fiber cable 1. The cut position of the cut 21 b is, for example, the position of the mark portion 13 on the outer periphery of the sheath 7. The notch 21b is formed using the tool 17 used when forming the aforementioned notch 21a as it is. That is, the notch depth of the notch 21b is the arrangement depth of the tension member 9, and substantially coincides with the depth B in FIG.

  By providing the cuts 21b on both sides of the optical fiber cable 1, the sheath 7 can be excised as shown in FIG. In this state, the opening portion can be formed in a part of the exposed protective layer 11 by bending the optical fiber cable 1 or the like. That is, the divided pieces 11a and 11b can be separated by the divided portion 12 to form a gap. The optical fiber core wire can be branched by taking out the internal optical fiber core wire 3 from the gap.

  Even if the sheath 7 is not completely excised, as shown in FIG. 4B, the sheath 7 may be peeled with the cut 21a as one place. Even in this case, the internal optical fiber core wire 3 can be taken out by forming a gap in the exposed divided portion 12 of the protective layer 11. In addition, since the tension member 9 is not provided in the division | segmentation piece 11b, a deformation | transformation is easier. For this reason, a gap can be easily formed by slightly bending the optical fiber cable 1 on the divided piece 11b side.

  FIG. 5 is a view showing a state in which the branched optical fiber 3a is taken out. As shown in FIG. 5A, a hole 23 is provided in a part of the divided piece 11b. The hole 23 may be formed in the protective layer 11 in advance. The branched optical fiber 3a is taken out from the hole 23, and the protective layer 11 (divided pieces 11a and 11b) is integrated at the divided portion and returned to a cylindrical shape. Further, the branched optical fiber is completed by returning the cut sheath 7 or waterproofing the branch portion by another method.

  In addition, as shown in FIG.5 (b), after partly cutting off the division | segmentation piece 11b and performing a branch operation | work in this site | part, it is branched light from the hole 23 provided in the said division | segmentation piece 11c concerned. The fiber 3a may be taken out. Since the split piece 11b is not provided with a tension member, it can be easily cut off.

  Moreover, as shown in FIG. 6, the internal branch optical fiber 3a may be taken out by separately inserting a wire member 25 between the divided pieces 11a and 11b (divided portion 12). FIG. 6B is a cross-sectional view taken along the line CC of FIG.

  The through member 25 is, for example, an L-shaped member divided into two parts, and a notch is formed in part. By combining the L-shaped member, a rod-shaped member having a substantially T-shaped cross section is formed, and the hole 23 is formed by attaching the notch portions to each other.

  After the branched optical fiber 3a is taken out from the hole 23, the sheath 7 cut out to the outside together with the wiring member 25 can be returned, or the branched portion can be waterproofed by other methods. Note that the method of taking out the branched optical fiber 3a from the protective layer 11 is not limited to the above-described example. For example, the technique used for the protective layer 11 may be formed on the sheath 7 with a part of the protective layer 11 removed. In addition, in the state where the protective layer 11 and the sheath 7 are removed, the method may be used for other members, and the entire branch portion may be protected by the other members.

  The optical fiber cable 1 may be configured as follows. FIG. 7 is an example showing a manufacturing method of the optical fiber cable 1. First, as shown in FIG. 7A, a plurality of optical fiber core wires are arranged in the protective layer 11 in advance. Next, the outer periphery of the protective layer 11 is wound with the resin tape 27 in a state where the divided pieces 11 a and 11 b are combined. The resin tape 27 can prevent the split pieces 11a and 11b from being displaced or a gap from being generated in the split portion 12.

  From this state, as shown in FIG.7 (b), the sheath 7 is extrusion-coated on the outer periphery. Here, the melting point of the resin constituting the resin tape 27 is equal to or lower than the melting point of the resin constituting the sheath 7. Therefore, when the sheath 7 is extrusion-coated, the resin tape 27 is melted and fused to the sheath 7. The resin constituting the protective layer 11 is higher than the melting point of the resin constituting the sheath 7. For this reason, the sheath 7 and the protective layer 11 are not fused. In order to more reliably prevent the sheath 7 and the protective layer 11 from being fused, a resin film or the like as a peeling member may be provided on the outer periphery of the protective layer 11. By providing the peeling member, it is possible to more reliably prevent the sheath 7 and the protective layer 11 from being fused. As described above, the melting point of the resin constituting the protective layer 11 is desirably higher than the melting point of the resin constituting the sheath 7, but the present invention is not limited to this. As long as the above-described branching portion can be formed, the melting point of the resin constituting the protective layer 11 and the melting point of the resin constituting the sheath 7 may be substantially the same. It is also possible to configure with the amount of the resin material.

  In this way, when the sheath 7 is peeled off, the sheath 7 and the protective layer 11 can be easily peeled off, and the resin tape 27 is removed integrally with the sheath 7. It is also easy to separate.

  As described above, according to the present embodiment, the optical fiber cable 1 can be easily branched without damaging the internal optical fiber. At this time, since the protective layer 11 is divided into a plurality of pieces in advance, it is easy to take out the optical fiber core wire from the inside of the protective layer 11 after removing the sheath 7.

  Further, since the tension member 9 is not provided in the divided piece 11b, the divided pieces 11a and 11b can be easily separated and the divided piece 11b can be cut off. In addition, since the split part 12 with the split pieces 11a and 11b is not formed in a straight line, when the optical fiber cable 1 is bent, the split piece is not deformed in the direction in which the split part 12 opens. It is possible to prevent the split pieces from being deformed in the opening direction. Moreover, since the optical fiber holding part 5 is provided, the inner optical fiber core wire 3 is not sandwiched between the split parts 12.

  Next, another embodiment will be described. In the following embodiment, the same reference numerals as those in FIG. 1 are used for the same functions as those of the optical fiber cable 1 shown in FIG.

  FIG. 8A is a cross-sectional view showing the optical fiber cable 1a. The optical fiber cable 1a is different from the optical fiber cable 1 in that the dividing portion 12 is formed in a straight line in the cross section. Even if it forms in this way, if the resin tape 27 etc. which were mentioned above are used, it can prevent that the division | segmentation pieces 11a and 11b slip | deviate to a horizontal direction at the time of manufacture. In addition, when a force is applied to the protective layer 11 or the cable from the outside, in order to prevent the split part from opening and the inner optical fiber core wire from being caught in the gap, a film or a tape is disposed in the split part. Alternatively, the optical fiber may be held at the approximate center of the protective layer 11 by the optical fiber holding unit 5.

  FIG. 8B is a cross-sectional view showing the optical fiber cable 1b. The optical fiber cable 1 b is different from the optical fiber cable 1 in the arrangement of the tension member 9 and the dividing portion 12. In the optical fiber cable 1b, the tension member 9 is provided only in one place. Further, the dividing portion 12 is formed so as to divide the protective layer 11 in half. Thus, it is not necessary to change the size of the divided pieces 11a and 11b. Moreover, you may form the division part 12 toward the radial direction from the center of the optical fiber cable 1b.

  Fig.9 (a) is sectional drawing which shows the optical fiber cable 1c. The optical fiber cable 1 c is different from the optical fiber cable 1 in the form of the dividing portion 12. In the optical fiber cable 1c, the dividing portion 12 is not formed in a straight line in the cross section but has an uneven shape. That is, the divided pieces 11a and 11b are formed into a cylindrical shape when the concave and convex shapes of the divided portions 12 mesh with each other. By doing in this way, it can prevent more reliably the division | segmentation piece 11a, 11b, and when the force which deform | transforms into the optical fiber cable 1c is added, it is more formed that a clearance gap is formed in the division part 12. Can be prevented.

  FIG. 9B is a cross-sectional view showing the optical fiber cable 1d. The optical fiber cable 1d is formed with a tensile member 9a on the side of the split piece 11b with respect to the optical fiber cable 1. By doing in this way, it is possible to hold | maintain the tension | tensile_strength of an optical fiber cable also on the split piece 11b side. At that time, the size and material of the strength member (tension member) may be changed in each divided piece. In order to improve the rear branching performance, it is preferable to use a tensile body having a smaller size or a lower tensile strength than that on the divided piece 11a side.

  FIG. 10A is a cross-sectional view showing the optical fiber cable 1e. The optical fiber cable 1 e is different from the optical fiber cable 1 in the aspect of the dividing portion 12. In the optical fiber cable 1e, the dividing portion 12 is not formed in a straight line in the cross section but has an uneven shape. That is, the divided pieces 11a and 11b are formed into a cylindrical shape when the concave and convex shapes of the divided portions 12 mesh with each other. In the optical fiber cable 1c, the concave and convex shape is a triangular wave shape with respect to the split surface. However, in the fiber cable 1e, a split surface that is concentric with the cylindrical shape of the protective layer 11 is formed. Therefore, the contact portion between the divided pieces is large, and it is possible to more reliably prevent the occurrence of a shift or a gap between the divided portions.

  FIG.10 (b) is sectional drawing which shows the optical fiber cable 1f. The optical fiber cable 1 f differs from the optical fiber cable 1 in the internal shape of the cylinder of the protective layer 11. That is, in the optical fiber cable 1f, the space inside the protective layer 11 is not circular in cross section but is substantially rectangular. In the present invention, the internal shape of the protective layer 11 can be set arbitrarily.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, the configurations described in the above embodiments can be naturally combined. Moreover, a division | segmentation piece is good also as 3 divisions or more, and the shape of each division | segmentation piece can be set arbitrarily. Further, the arrangement and shape of the tension members and the like in the cross section are not limited to the illustrated example, and can be appropriately changed within a range in which the problem of the present invention can be solved.

  Further, in the above-described embodiment, the cuts 21b are formed at the diagonal positions of the cable, but the present invention is not limited to this. For example, as shown in FIG. 11A, the cut 21b may be formed with an angle in the cable cross section. Further, even if the sheath 7 is not completely excised, as shown in FIG. 11B, the cut 21b may be formed only at one place. Also. As shown in FIG. 11C, the portion where the cut 21b is formed does not necessarily have to be the position of the tension member 9.

1, 1a, 1b, 1c, 1d, 1e, 1f .... Optical fiber cable 3 ... Optical fiber core 5 ... Optical fiber holder 7 ... Sheath 9 ... Tension member 9a ... Strength member 11 ......... Protective layers 11a, 11b ......... Divided piece 12 ......... Divided part 13 ......... Mark part 17 ......... Tool 19 ......... Blade 21a, 21b ......... Incision 23 ......... Hole 25 .... Connection member 27 .... Resin tape

Claims (10)

In a cross section of an optical fiber cable comprising an optical fiber core, a protective layer protecting the optical fiber core, and a sheath formed on the outer periphery of the protective layer,
A tension member is embedded in the protective layer,
The protective layer has a continuous portion in the longitudinal direction, and the protective layer can be divided into a plurality of sections in a cross section,
The split part is an optical fiber cable formed in at least two places in a cross section, and the two split parts in any two places are not parallel to each other but formed at an angle,
In the direction of extension line is not suited to the center of the optical fiber cable of the inner peripheral surface end portion of the protective layer of the divided portion of the arbitrary two points in the cross section, the divided portions of the arbitrary two points An optical fiber cable characterized in that a single chevron is formed by the extension line . The two divided portions at any two locations divide the protective layer into a first divided piece and a second divided piece smaller than the first divided piece,
The optical fiber cable according to claim 1, wherein the divided portion is formed in a straight line in a cross section.   An uneven shape is formed in the section in the divided portion, and the divided pieces of the respective protective layers divided into a plurality of pieces can be meshed with each other in the uneven shape. The optical fiber cable according to 1.   The divided pieces of each of the protective layers divided into a plurality of pieces can be divided into a divided piece provided with a tension member and a divided piece provided with no tension member. An optical fiber cable according to any one of the above.   The optical fiber cable according to any one of claims 1 to 4, wherein the protective layer is made of a resin having a melting point higher than that of the resin constituting the sheath.   The optical fiber cable according to any one of claims 1 to 5, wherein a peeling member is provided between the protective layer and the sheath.   A resin tape having a melting point equal to or lower than the melting point of the resin constituting the sheath is wound around the outer periphery of the protective layer, and the resin tape and the sheath are fused and integrated. The optical fiber cable according to any one of claims 1 to 6.   The optical fiber cable according to claim 1, wherein the optical fiber core wire is held by a holding member inside the protective layer. Using the optical fiber cable according to any one of claims 1 to 8,
Cut from the outer peripheral side of the optical fiber cable to the depth where the tip of the blade contacts the tension member in the circumferential direction of the sheath, and the sheath is connected to the optical fiber cable so that the cut depth is substantially the same as the cut depth. The protective layer is exposed by cutting along the longitudinal direction, and the protective layer is divided by the divided portion, and an internal optical fiber core wire is taken out from the divided portion and branched. Branch method of optical fiber cable.   After taking out the optical fiber core, a hole through which the branched optical fiber core can be penetrated is formed in the protective layer, and the branched optical fiber core is branched to the outside through the hole, and then the entire branch portion The method for branching an optical fiber cable according to claim 9, wherein the optical fiber cable is waterproofed.

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