JP6268774B2 - Optical cable - Google Patents

Description

  The present invention relates to an optical cable in which an intermittent tape core wire in which three or more optical fiber core wires are arranged in parallel is housed in a slot rod.

  With the recent expansion of broadband services such as video distribution, IP (Internet Protocol) telephone, and data communication, the number of subscribers to home-use data communication service (FTTH: Fiber To The Home) using optical fiber is increasing. In this FTTH, a drop optical cable is used to drop a subscriber's house from a trunk optical cable.

  In order to transmit a large amount of data at a high speed and to simplify the storage and work in the optical cable, the optical cable such as the drop optical cable has a plurality of optical fiber cores (sometimes called optical fiber strands). Optical fiber tape core wires (hereinafter also referred to as tape core wires) that are arranged in parallel and bonded together are used. As the tape core wire, a fiber in which optical fiber core wires having the same length are juxtaposed with each other over the entire length is used.

  However, in order to drop the optical fiber to the subscriber's home, etc., the optical fiber tape core wire in which a plurality of optical fiber core wires are arranged in parallel is finally separated (branched) into a single optical fiber core wire. There is a need. In order to cope with this, an optical fiber core wire in which optical fiber core wires are bonded intermittently is also used. Intermittent bonding between optical fiber cores has features such as an increase in concentrating density, reduction in transmission loss due to bending, and ease of single-core operation, and is excellent for high-density fiber mounting.

For example, Patent Literature 1 discloses a tape core wire that facilitates single-fiber separation of optical fiber core wires by intermittently connecting adjacent optical fiber core wires in the longitudinal direction (hereinafter referred to as an intermittent tape core wire). An optical cable in which the intermittent tape core wire is housed in a slot rod and a method for manufacturing the intermittent tape core wire are disclosed. Patent Documents 2 and 3 also disclose a method for manufacturing an intermittent tape core wire.
Note that Patent Document 4 discloses a non-intermittent tape core wire having a feature in the thickness of the tape covering portion in order to reduce the difference in wire length of each optical fiber core wire at low cost.

JP 2011-232733 A JP 2013-3516 A JP 2012-208310 A JP 2005-43719 A

  However, in the optical cables as described in Patent Documents 1 to 3, the intermittent tape core wire is accommodated with an extra length with respect to the slot rod in consideration of later removal of the intermittent tape core wire from the slot groove. It is necessary to keep it.

  Therefore, in the optical cables as described in Patent Documents 1 to 3, the extra intermittent tape core wire is left in the slot, and the remaining optical fiber core wire (fiber single core portion) of the intermittent tape core wire is a slot groove. Interference with the side wall will deteriorate transmission characteristics. In particular, the end center of the intermittent tape core wire easily interferes with the slot groove as compared with other optical fiber core wires (non-end optical fiber core wires), and the transmission characteristics of the end core are particularly likely to deteriorate.

  If the slot groove is enlarged, the transmission characteristics are improved. However, the optical cable becomes thicker, or a rib (slot for forming a slot groove on the slot rod and separating it from other slot grooves). The thickness of the rib) is reduced, and the mechanical strength of the optical cable is lowered.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide an optical cable in which an intermittent tape core wire in which three or more optical fiber core wires are arranged in parallel is housed in a slot rod. An object of the present invention is to maintain good fusion workability of the optical fiber contained in the tape core and to prevent the end of the intermittent tape from interfering with the side wall of the slot groove of the slot rod.

An optical cable according to the present invention is an optical cable including a slot rod in which intermittent tape core wires each having three or more optical fiber core wires arranged in parallel are stacked and housed, and a jacket covering the slot rod. Therefore, the length of the other optical fiber cores not positioned at both ends of the intermittent tape core wire is necessarily 0.005% of the length of the optical fiber core wires positioned at both ends of the intermittent tape core wire. Increased by ~ 0.05%.

  According to the present invention, in an optical cable in which an intermittent tape core wire in which three or more optical fiber core wires are arranged in parallel is housed in a slot rod, the optical fiber core wires positioned at both ends of the intermittent tape core wire are connected to other light. By making the length shorter than the fiber core, the end center of the intermittent tape core can be prevented from interfering with the side wall of the slot groove of the slot rod, so that the end center also has the same transmission characteristics as other optical fiber cores. Can do. Further, according to the present invention, since the difference in the lengths of the optical fiber cores is not increased too much, the fusion workability when fusing the optical fiber cores contained in the tape core wire may deteriorate. Absent.

It is sectional drawing which shows one structural example of the optical cable which concerns on one Embodiment of this invention. It is a figure which shows an example of the intermittent tape core wire accommodated in the slot groove | channel of the optical cable of FIG. It is sectional drawing in the BB line of FIG. 2A. It is sectional drawing in the CC line of FIG. 2A. It is sectional drawing in the DD line of FIG. 2A. It is a figure which shows the other example of the intermittent tape core wire accommodated in the slot groove | channel of the optical cable of FIG. It is sectional drawing in the BB line of FIG. 3A. It is sectional drawing in CC line of FIG. 3A. It is sectional drawing in the DD line of FIG. 3A. It is a figure which shows the result of having tested the transmission characteristic and the melt | fusion workability | operativity about the optical cable in which the 4-core intermittent tape core wire which concerns on one Embodiment of this invention was accommodated. It is a figure which shows the result of having tested the transmission characteristic and the melt | fusion workability | operativity about the optical cable in which the 8-core intermittent tape core wire which concerns on one Embodiment of this invention was accommodated.

[Description of Embodiment of the Present Invention]
First, embodiments of the present invention will be listed and described.
(1) An optical cable according to the present invention includes a slot rod in which intermittent tape cores in which three or more optical fiber cores are arranged in parallel are stacked and housed, and a jacket covering the slot rod. An optical cable in which the lengths of the other optical fiber cores are increased by 0.005% to 0.05% compared to the lengths of the optical fiber core wires positioned at both ends of the intermittent tape core wire. Yes. As a result, the end center of the intermittent tape core can be prevented from interfering with the side wall of the slot groove of the slot rod, and the end center can also ensure the same transmission characteristics as other optical fiber cores. Since the difference in the lengths of the optical fiber cores is not increased too much, the fusion workability when the optical fiber cores included in the tape core are fused is not deteriorated.

  (2) The slot rod preferably has a plurality of slot grooves formed in an SZ shape. Actually, the tape core wire in the slot groove of the SZ twisted TS (tape slot) type optical cable has a locus in the longitudinal direction of the slot groove curved in the SZ direction. It will be stored. Therefore, in the SZ twisted TS type optical cable, there is a greater possibility of contact (interference) between the slot groove and the end of the intermittent tape core wire than an optical cable having a slot groove twisted in one direction (spiral). The interference prevention effect of the present invention is more beneficial.

[Details of the embodiment of the present invention]
Hereinafter, specific examples of the optical cable according to the present invention will be described with reference to the accompanying drawings.
An optical cable 1 illustrated in FIG. 1 is an optical cable in which a jacket 14 is covered with a slot rod 11 in which intermittent tape core wires 20 are stacked and stored. The optical cable 1 may be an SZ twisted TS type optical cable or a unidirectional twisted TS type optical cable.

  Further, the optical cable 1 illustrated in FIG. 1 is provided with an upper winding tape (also referred to as a presser winding tape) 13 that is wound around the slot rod 11 in a vertical or horizontal manner. The outside of the covered slot rod 11 is covered. For example, the surface shape of the optical cable 1 is a circle having a diameter of about 5 to 25 mm. The upper tape 13 is generally provided, but may not be provided.

  The slot rod 11 is made of a resin such as plastic having a tension member 12 made of a steel wire, a steel stranded wire or the like embedded in the center portion and having a plurality of slot grooves 11a formed in an SZ shape or a spiral shape on the outer surface side. A rod, also called a spacer. The slot groove 11a is a groove for laminating and storing one or a plurality of intermittent tape core wires 20, and FIG. 1 shows an example having five slot grooves 11a.

  The slot rod 11 has a slot rib 11b to form a slot groove 11a and to be separated from other slot grooves 11a. That is, the slot groove 11a is a groove between adjacent slot ribs 11b. In addition, the slot groove 11a has a rectangular cross section, but is not limited to this, and may have any shape as long as the intermittent tape core wire 20 can be laminated.

  Although not shown, in order to identify the position of a predetermined slot groove 11a among a plurality of slots, a predetermined slot rib 11b dividing the slot groove 11a has a V shape, a rectangular shape, or a U shape. For example, colored resins having various cross-sectional shapes may be attached.

  As an accommodation state (accommodation form) of the tape core wire 20, it is sufficient that one or a plurality of sheets are stacked and accommodated for each slot groove 11 a. In particular, it is preferable to laminate one layer per layer from the viewpoint of the effect. In such an example, in FIG. 1, the intermittent tape core wires 20 are laminated in five layers one by one and stored in each slot groove 11a. An example is given.

In addition, for example, M (M is an integer of 2 or more) can be stacked, that is, N intermittent tape cores can be arranged in one layer, and N can be stacked. In this case as well, this embodiment is useful because adjacent end centers in the layer may come into contact with each other.
Further, one or more tape core wires 20 may be folded in the width direction and stored. In particular, in the present embodiment, since an intermittent tape core wire is used as the tape core wire 20, it can be bent sufficiently. However, from the feature of this embodiment described later, the side wall of the slot groove 11a is stored so that both end sides before bending are in contact.

In addition, the upper tape 13 is generally formed by forming a nonwoven fabric into a tape shape, or by bonding a base material such as PET and the nonwoven fabric. The upper tape 13 may be wound after a rough winding string (not shown) is wound around the outer periphery of the slot rod 11.
The jacket 14 is made of a resin such as polyethylene and is formed by extrusion molding.

  Next, an example of the intermittent tape core wire 20 will be described with reference to FIGS. 2A to 2D. FIG. 2A is a diagram illustrating an example of the intermittent tape core wire 20 accommodated in the slot groove 11a, and is a diagram illustrating a state in which the 4-fiber intermittent tape core wire is opened in the width direction. 2B, FIG. 2C, and FIG. 2D are cross-sectional views of the intermittent tape core line (cross-section perpendicular to the longitudinal direction of the intermittent tape core line) in the BB line, CC line, and DD line of FIG. 2A, respectively. Figure).

  The intermittent tape core accommodated in the slot groove 11a is an intermittent optical fiber ribbon in which three or more optical fiber cores are arranged in parallel. The intermittent tape core wire 20 illustrated in FIG. 2A is an intermittent tape core wire (that is, a 4-core intermittent tape core wire) composed of four optical fiber core wires 21 having an intermittent structure. That is, the four-fiber intermittent tape core wire 20 includes four optical fiber core wires 21 arranged in parallel (that is, arranged in a parallel line), and a connecting portion 22 in the longitudinal direction between the adjacent optical fiber core wires 21. The non-connection part 23 is formed intermittently.

  Further, the optical fiber core wire 21 is a single-fiber optical fiber including a so-called optical fiber element obtained by coating a glass fiber with a fiber coating, or a fiber core having a colored layer on its outer surface. (Single optical fiber).

  The optical fiber core 21 preferably has a glass diameter of approximately 125 μm, and the outer diameter of the optical fiber core coating (fiber coating) excluding the tape coating layer in the intermittent tape core 20 is 190 μm to 220 μm. Thereby, the intermittent tape core wire 20 having a pitch between the core wires of about 250 μm can be manufactured, and the diameter of the optical cable can be reduced. However, the outer diameter of the optical fiber core 21 is not limited to about 200 μm, and other outer diameter sizes may be adopted. For example, the coating diameter of the optical fiber core 21 may be around 250 μm. Further, the outer diameter of the optical fiber coated with a colored layer in order to give the identification of the core is, for example, about 205 μm when the coating diameter of the optical fiber is about 200 μm.

  As shown in FIG. 2B, a tape coating 24 made of an ultraviolet curable resin or the like is formed around the optical fiber core wire 21. As shown in FIGS. 2B to 2D, the tape coating 24 of the adjacent optical fiber core wires 21 is connected in the connecting portion 22, and the tape coating 24 of the adjacent optical fiber core wires 21 is connected in the non-connecting portion 23. It is not done, it is in a separated state. 2B to 2D show examples in which the entire circumference of each optical fiber core 21 is covered with the tape coating 24, but the adjacent optical fiber cores 21 are in direct contact with each other and covered with the tape coating. An unstructured form can also be adopted.

  Further, when viewed in the tape width direction, the portions where the connecting portions 22 and the non-connecting portions 23 are alternately arranged and the portions where only the non-connecting portions 23 are arranged alternately appear at a predetermined pitch in the longitudinal direction. Examples like this are given. However, the arrangement pattern of the connecting portion 22 and the non-connecting portion 23 is not limited to this example. For example, the connecting part and the non-connecting part may be provided in common in the length direction as described in Patent Document 1. Further, in FIG. 2A, as a more preferable example, an intermittent pattern that is line symmetric with respect to the boundary between the second line and the third line located in the center in the width direction will be described, but the present invention is not limited to this. Absent. Of course, the cross-sectional shape of the connection part 22 and its connection method are not ask | required.

  As a main feature of the present embodiment, the optical cable 1 has a fiber length at an end center (a core that easily interferes with the slot) of the intermittent tape core wire 20 that is shorter than the others, thereby preventing interference with the slot groove 11a. I am doing so.

  Actually, the intermittent tape core wire 20 has a single core portion (non-connecting portion) and an adhesive portion (connecting portion), and the transmission characteristics deteriorate due to interference of the remaining single core portion with the slot groove 11a. Therefore, in this embodiment, the length of the end optical fiber core is made shorter than the length of other optical fiber cores (non-end center optical fiber cores including the center optical fiber core), The interference with the slot groove is prevented and the deterioration of the transmission characteristics is prevented. However, if the difference in the lengths of the optical fiber cores is too large, the fusion workability when fusing the tape cores (optical fiber cores included in the tape cores) deteriorates. Is not preferable.

  In consideration of these points, as a main feature of the present embodiment, the optical cable 1 is different from the length of the optical fiber cores 21 positioned at both ends of the intermittent tape core wire 20 (that is, the length of the end fiber core). The length of the optical fiber core 21 (in this example, the two central optical fiber cores 21) is increased by 0.005% to 0.05%.

  Thus, by making the optical fiber cores located at both ends of the intermittent tape core wire shorter than the other optical fiber core wires, the end center of the intermittent tape core wire does not interfere with the side wall of the slot groove of the slot rod. Therefore, the transmission characteristics similar to those of other optical fiber cores can be secured at the end center. In addition, since the difference in the lengths of the optical fiber cores is not increased too much, the fusion workability when the optical fiber cores included in the tape core are fused is not deteriorated.

  2A to 2D exemplify four-core intermittent tape cores (four-core intermittent adhesive tapes), but the number N of cores of the intermittent tape cores housed in the slot groove 11a is not limited to four. There are three or more. An even number is generally adopted as the number N of the cores of the tape core, but may be an odd number.

  Another example of the intermittent tape core wire will be described with reference to FIGS. 3A to 3D. FIG. 3A is a view showing another example of the intermittent tape core wire accommodated in the slot groove 11a, and is a view showing a state where the 4-fiber intermittent tape core wire is opened in the width direction. 3B, FIG. 3C, and FIG. 3D are cross-sectional views of intermittent tape cores along the BB line, the CC line, and the DD line in FIG. 3A, respectively.

  The intermittent tape core wire 30 illustrated in FIG. 3A is an intermittent tape core wire (hereinafter, also referred to as an 8-core intermittent tape core wire) composed of eight optical fiber core wires 31 having an intermittent structure. That is, in the four-fiber intermittent tape core 30, eight optical fiber cores 31 are arranged in parallel, and the connecting portion 32 and the non-connecting portion 33 are intermittent in the longitudinal direction between the adjacent optical fiber core wires 31. Is formed.

  The optical fiber core wire 31 is the same as the optical fiber core wire 21 of FIG. 2A, and as shown in FIG. 3B, a tape coating 34 made of an ultraviolet curable resin or the like is formed around the optical fiber core wire 31. Yes. Other application examples of the 4-core intermittent tape core wire 20 illustrated in FIG. 2A and the like can be similarly applied to the 8-core intermittent tape core wire 30.

  Various shapes and manufacturing methods have been proposed so far for the intermittent tape core wires such as the 4-core intermittent tape core wire 20 and the 8-core intermittent tape core wire 30. For example, in the first method, the connecting portion to which the adhesive resin or the coating resin is applied for a predetermined length in the longitudinal direction between the adjacent optical fiber cores and the adhesive resin or the coating resin for the predetermined length are not applied. This is a method of alternately forming unconnected portions. In the second method, an ultraviolet curable resin is applied to the entire length of a plurality of optical fiber cores, and thereafter, ultraviolet (UV) irradiation is intermittently performed in the longitudinal direction to cure a cured portion (connecting portion) of the ultraviolet curable resin. And uncured portions (non-connecting portions) are alternately formed. The third method is a method in which a tape core wire is first formed, a cut is formed with a cutter blade in the longitudinal direction of the common coating of the tape core wire, and a connection portion and a non-connection portion are alternately formed. .

  Any one of the first to third methods described above may be used as a method for manufacturing the intermittent tape core wire used in the present embodiment. However, in this embodiment, it is necessary to make the lengths of the optical fiber core wires different from both ends. For this purpose, for example, the length of the optical fiber core may be distributed by adjusting the tension applied to the optical fiber core during the manufacture of the intermittent tape.

Next, with reference to FIG. 4 and FIG. 5, test results of transmission characteristics and mechanical characteristics of the optical cable according to the present embodiment will be described, and test results of transmission characteristics and mechanical characteristics of the conventional optical cable will be described for comparison. To do.
FIG. 4 shows the results of testing the transmission characteristics and the fusion workability of the optical cable in which the four-fiber intermittent tape core according to the present embodiment is accommodated and the optical cable in which the conventional four-core intermittent tape core is accommodated. FIG. FIG. 5 is a diagram showing test results when an 8-core intermittent tape core is employed instead of the 4-core intermittent tape core of FIG.

  Also, the transmission characteristics and fusion workability of the optical cable can be evaluated by adjusting the tension applied to the optical fiber core during the manufacture of the intermittent tape, thereby changing the length of the optical fiber core and inserting the intermittent tape core into the slot groove. The SZ-twisted TS type optical cable with the upper tape and the outer cover was used. In FIG. 4 and FIG. 5, the evaluation results of both characteristics are expressed as “poor” when bad (in the case of NG) and as “good” when good.

  Further, after the evaluation, the length of the optical fiber core wire was measured. More specifically, as for the length of the optical fiber core, the intermittent tape core wire was used for 10 m, the resin of the connecting portion was peeled off, and the length was compared for each optical fiber core wire. 4 and 5, in the intermittent tape core, the k-th optical fiber core (k-th core) counted from the optical fiber core at one end is expressed as “kC”.

  First, in each of the five slot grooves in the optical cable as shown in FIG. 1, four-fiber intermittent tape cores as shown in FIG. Manufactured. FIG. 4 shows the test results of the optical cable.

  As the four-fiber intermittent tape core wire 20 having the characteristics according to the present embodiment, transmission characteristics and fusion workability at normal temperatures were confirmed for the following sample Nos. A-1 to A-5. Sample No. A-1 accommodates a 4-core intermittent tape core wire in which 2C and 3C are both 0.020% longer than 1C as the end center and 4C as the other end center. Sample No. A-2 accommodates a 4-fiber intermittent tape core wire in which 2C and 3C are both 0.010% longer than 1C and 4C.

Sample No. A-3 accommodates a 4-fiber intermittent tape core wire that is longer by 0.040% and 0.030 for 2C and 3C, respectively, for 1C and 4C. Sample No. A-4 contains a 4-fiber intermittent tape core wire in which 2C and 3C are both 0.050% longer than 1C and 4C. Sample No. A-5 accommodates a 4-fiber intermittent tape core wire in which 2C and 3C are longer by 0.005% and 0.010, respectively, for 1C and 4C.
As a result, Sample Nos. A-1 to A-5 all had good transmission characteristics and fusion workability.

  Moreover, the transmission characteristics and fusion workability | operativity at normal temperature were confirmed about the following sample No.P-1 to P-4 as a conventional 4-core intermittent tape core wire. Sample No. P-1 accommodates a 4-fiber intermittent tape core wire in which 2C and 3C are both 0.010% shorter than 1C and 4C. Sample No. P-2 accommodates a 4-core intermittent tape core wire in which 2C and 3C are shorter by 0.040% and 0.050% than 1C and 4C, respectively.

Sample No. P-3 accommodates a 4-fiber intermittent tape core wire that is longer by 0.100% and 0.110 for 2C and 3C, respectively, for 1C and 4C. Sample No. P-4 accommodates a 4-fiber intermittent tape core wire with 2C and 3C shorter than 0.080% and 0.095, respectively, for 1C and 4C.
As a result, sample Nos. P-1, P-2, and P-4 all had poor transmission characteristics, and sample Nos. P-3 and P-4 all had poor fusion workability.

  Next, each of the five slot grooves in the optical cable as shown in FIG. 1 is stacked with 10 layers of 8-fiber intermittent tape cores as shown in FIG. A 400-fiber optical cable was manufactured. FIG. 5 shows the test result of the optical cable.

  As the eight-fiber intermittent tape core wire 30 having the characteristics according to the present embodiment, transmission characteristics and fusion workability at room temperature were confirmed for sample Nos. A-1 to a-4 among the samples shown in FIG. In sample No. a-1, 2C, 3C, 4C, 5C, 6C, and 7C are 0.040%, 0.045%, 0.050%, and 0.035% with respect to 1C and 8C, which are the end centers, respectively. , 8-fiber intermittent tape core wires that are long by 0.050% and 0.020% are housed. In sample No. a-2, 2C, 3C, 4C, 5C, 6C, and 7C are 0.010%, 0.020%, 0.015%, 0.010%, and 0.025, respectively, for 1C and 8C. %, 0.010% long 8-fiber intermittent tape cord is housed.

In sample No. a-3, 2C, 3C, 4C, 5C, 6C, and 7C are 0.005%, 0.005%, 0.010%, 0.010%, and 0.015 for 1C and 8C, respectively. %, And an 8-fiber intermittent tape core wire long by 0.015% is housed. In sample No. a-4, 2C, 3C, 4C, 5C, 6C, and 7C are 0.005%, 0.045%, 0.035%, 0.035%, and 0.025, respectively, for 1C and 8C. %, 0.08% long 8-fiber intermittent tape cord is housed.
As a result, Sample Nos. A-1 to a-4 all had good transmission characteristics and fusion workability.

Moreover, as a conventional 8-fiber intermittent tape core wire, transmission characteristics and fusion workability at room temperature were confirmed for the following sample Nos. P-1 to p-3 among the samples shown in FIG. Sample No. p-1 is 0.010%, 0.020%, 0.015%, 0.025%, 0.020 for 2C, 3C, 4C, 5C, 6C, and 7C, respectively, for 1C and 8C %, It contains 8-fiber intermittent tape core wires which are short by 0.015%. Sample No. p-2 is 0.08%, 0.095%, 0.090%, 0.080%, and 0.105 for 2C, 3C, 4C, 5C, 6C, and 7C, respectively, for 1C and 8C. %, 0.085% long 8-fiber intermittent tape cord is housed. In sample No. p-3, 2C, 3C, 4C, 5C, 6C, and 7C are 0.080%, 0.080%, 0.090%, 0.060%, and 0.075, respectively, for 1C and 8C. %, 0.090% short 8-fiber intermittent tape cord is housed.
As a result, sample Nos. P-1 and p-2 both had poor transmission characteristics, and sample Nos. P-2 and p-3 both had poor fusion workability.

  From the above, as compared with the lengths of the optical fiber cores positioned at both ends of the intermittent tape core wire as in the present embodiment, the lengths of the other optical fiber core wires are 0.005% to 0.05%. It can be seen that when it is configured to be long, both transmission characteristics and fusion workability are improved. Moreover, although it showed with the SZ twisted TS type | mold optical cable, the same result was obtained even if it was the unidirectional twisted TS type | mold optical cable.

  As described above, the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is not limited to the examples described above, but is defined by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims. .

DESCRIPTION OF SYMBOLS 1 ... Optical cable, 11 ... Slot rod, 11a ... Slot groove, 11b ... Slot rib, 12 ... Tension member, 13 ... Top wound tape, 14 ... Outer jacket, 20, 30 ... Intermittent tape core wire, 21, 31 ... Optical fiber core Wires, 22, 32 ... connecting parts, 23, 33 ... non-connecting parts, 24, 34 ... tape coating.

Claims (2)

An optical cable comprising: a slot rod in which three or more optical fiber core wires are arranged in parallel; and a slot rod in which intermittent tape core wires are stacked and stored; and a jacket covering the slot rod,
Compared to the lengths of the optical fiber cores positioned at both ends of the intermittent tape core wire, the lengths of the other optical fiber cores not positioned at both ends of the intermittent tape core wire are necessarily 0.005% to 0. An optical cable that is 0.05% longer.   The optical cable according to claim 1, wherein the slot rod has a plurality of slot grooves formed in an SZ shape.

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