JP2002072005A - Optical fiber cord having single fiber cord branching part of multiple optical fiber and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber cord having a single fiber cord branching part of a multiple optical fiber excellent in high reliability as a whole by improving reinforcement of a fusion spliced part and workability for treating high- tensile bodies. SOLUTION: The optical fiber cord having the single fiber cord branching part 31 of the multiple optical fiber is formed by connecting plural number of single optical fiber cords 29 to whose one end optical connectors 30 are connected respectively to a multiple optical fiber tape cord 28 by fusion splicing 20. Optical fibers 13 of plural number of single optical fiber cords 29 are fusion spliced in the fusion splicing part in the shaped that the optical fibers are aligned so as to coincide with the pitch of the coated optical fiber of the multiple optical fiber tape cord and are formed into a tape. The high-tensile bodies 18 and 19 are prepared in at least one side of the single optical fiber cords 29 or the multiple optical fiber cord 28, and the high-tensile bodies are arranged in the outside of a heat shrinkable member 23 protecting fusion splicing and are separately fixed by another heat shrinkable members 24a and 24b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cord in which a multi-core optical fiber tape cord or a ribbon is separated into single fibers, and an optical connector is connected to each of the separated optical fiber cords, and a manufacturing method thereof. It is about the method.

[0002]

2. Description of the Related Art A multi-core optical fiber tape cord is separated into single-core optical fibers by removing a common cord jacket and a tape core coating on a terminal side of a communication line, and each separated optical fiber is separated. Is converted into a single-core optical fiber, and an optical connector is connected to the end of the optical fiber. Regarding the technology for converting a multi-core optical fiber tape cord from multi-core to single-core, various proposals have been made to reduce the size of the separation structure, provide mechanical protection from external force, and provide durability.

[0003] The terms used in this specification are defined and used as follows. Optical fiber: An optical fiber coated with a urethane acrylate ultraviolet-curing resin or a thermosetting silicone resin when the optical fiber is drawn. Single core wire: 0.4m outer diameter with nylon etc. on the optical fiber
A single-core optical fiber with a coating of at least m. Tape core wire: A tape-shaped optical fiber in which a plurality of optical fiber strands are arranged in a line and bundled with a common coating. Single-core optical fiber cord: An optical fiber in which a sheath is sheathed on a single-core wire (hereinafter, abbreviated as a single-core cord). Multi-core optical fiber tape cord: An optical fiber in which a sheath is sheathed on a tape core wire (hereinafter, abbreviated as a tape cord). Single core branching: Dividing a tape cord or tape core from multiple cores to single core.

FIG. 4 shows an example of a conventional single core branch (Japanese Patent Publication No.
In the figure, reference numeral 1 denotes a 4-core ribbon, 2 denotes a manifold, 3, 9 denotes a protective tube, 4 denotes a heat-shrinkable member, 5 denotes an optical connector, 6 denotes a protective tube, Reference numeral 7 denotes an adhesive filler, and reference numerals 3a and 9a denote strength members. The manifold 2 includes a branch storage section 2a and a wire protection section 2b. The branch housing portion 2a is formed as a space for accommodating the mouth portion of the optical fiber 8 that is opened in a fan shape from the coating-removed end of the tape core 1 and is branched.
Is formed of a large number of thin tubes into which the branched optical fiber wires 8 are individually inserted.

[0005] In the above-described configuration, when the tape core 1 is branched into a single core, after removing the coating of the tape core at the end of the tape core 1 and exposing the optical fibers 8 individually, the optical fibers 8 are separated. The separated optical fiber wires 8 are separated and inserted into respective thin tubes of the optical fiber wire protection portion 2b,
The tip is made to protrude from the manifold 2. After that, protection is performed by covering the front of the manifold with a protective tube 3 having a tensile strength member 3a. Similarly, the tape core 1 is covered with a protection tube 9 having a tensile strength member 9a for protection.

After the single-branch of the tape core wire 1 is performed as described above, the heat-shrinkable adhesive 7 having a hot-melt type adhesive 7 applied in advance to include the ends of the protective tubes 3 and 9 is provided. The conductive member 4 is covered and shrunk by heating, and the branch portion is integrated with an adhesive 7 and sealed as shown in the figure.
Further, after that, the whole is covered with a protective tube 6 to provide mechanical protection, and finally, the protective tube 3 placed on the optical fiber 8 is covered.
The optical connector 5 is connected at the end of the optical connector 5.

However, it takes time to insert each optical fiber 8 into the thin tube of the wire protection part 2b. Further, since the optical fiber 8 has a loose structure in this tube, the tube becomes shorter than the optical fiber due to a difference in linear expansion coefficient, and the meandering of the optical fiber cannot be sufficiently absorbed. The wire may bend and cause loss. In connection with the optical connector, it is necessary to position the loose optical fiber 8 in order to hold it in the center of the protective tube 3, which is also a labor-intensive operation. Furthermore, the connection of the optical connector must be performed after all branching operations have been completed, and there is a limit to shortening the lead time.
If the delivery date was short, we could not handle it.

FIG. 5 shows another example of a conventional single fiber branch (Japanese Patent Laid-Open No.
In the figure, reference numeral 1 'denotes a tape code, 5' denotes an optical connector, and 9 denotes a conversion section (multi-core).
(Single core), 10 indicates an optical fiber ribbon cord. In this conventional example, an optical fiber ribbon cord (hereinafter, referred to as a single fiber branch)
(Abbreviated as a ribbon code) 10. In the ribbon cord 10, a plurality of single-core cords 10a are arranged in parallel, and adjacent cord jackets 10d are fused to each other.
It is of a shape that can be cut into a single-core cord by fusing the fused part. Each single-core optical fiber cord 10a longitudinally attaches a tensile member 10c to the outside of the optical fiber strand 10b,
It is covered with a jacket 10d.

One end of the ribbon cord 10 is separated from each other to form a single-core cord 10a, and an optical connector 5 'is connected to the end in advance. The other end of the ribbon cord 10 is connected to the tape cord 1 ′ by the converter 9. For the connection in the conversion unit 9, the sheath 10d on the ribbon cord 10 side is peeled off and the optical fiber 10b (0.25 m
The mUV-coated state) is aligned and integrated by fusing or resin bonding to have the same dimensions as the tape cord 1 '. It is said that this enables batch connection (fusion connection, mechanical connection, connector connection), but no specific connection is disclosed.

In the example shown in FIG. 5, compared to the example shown in FIG. 4, the operation time can be reduced because no branch pipe is used, and the lead time can be reduced because the optical connector can be connected to the ribbon cord in advance. Can be achieved. However, in the case where the fusion splicing is used for the collective connection, other operations, such as reinforcement of the fusion splicing and fixing of the tensile strength member, which are not performed in the example of FIG. 4, are added. For this reason, new work, further miniaturization of the connection portion, and further improvement for high reliability are desired.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and uses a fusion splicing technique capable of shortening the lead time to perform a single-fiber branch to reinforce a fusion spliced portion. It is an object of the present invention to provide an optical fiber cord having a single-branch portion of a multi-core optical fiber which is improved in workability of a tensile strength member and has high reliability as a whole, and a method of manufacturing the same.

[0012]

According to the present invention, there is provided an optical fiber cord having a single-branch portion of a multi-core optical fiber, comprising: a plurality of single-core optical fiber cords each having an optical connector connected to one end; The tape cord or the tape core is connected by fusion splicing. The optical fiber strands of the plurality of single-core optical fiber cords are arranged in a line at the fusion spliced portion so as to match the core pitch of the multi-core optical fiber tape cord or tape core wire, and are taped. Spliced. A strength member is provided on at least one of the single-core fiber optic cord and the multi-core fiber optic tape cord or the tape core wire, and the strength member is disposed outside the heat-shrinkable member for protecting the fusion splicing, and is individually separated by another heat-shrinkable member. Characterized in that it is fixed to

Further, according to the present invention, there is provided a method for manufacturing an optical fiber cord having a single-core branch portion of a multi-core optical fiber, comprising: a plurality of single-core optical fiber cords each having an optical connector connected to one end; Prepare the cord or tape core. The optical fibers at the other ends of the plurality of single-core optical fiber cords are exposed, and the single-core optical fiber cords are taped by being arranged in a line so as to coincide with the core pitch of the multi-core optical fiber tape cord or tape core. After that, the coating necessary for fusion splicing is removed and the end face is treated, and the end of the multi-core optical fiber tape cord on the single-branch side is subjected to the coating removal and the end face necessary for fusion splicing, and the single-core optical fiber cord is removed. And a multi-core optical fiber tape cord. Thereafter, the fusion spliced portion is reinforced by a heat-shrinkable member, and then the strength members of the single-core optical fiber cord and the multi-core optical fiber tape cord are fixed by a heat-shrinkable member different from the heat-shrinkable member. Is attached.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. FIG. 1A shows a state in which a four-core tape cord is branched into a single core, FIG. 1B shows an enlarged cross-sectional view of the single-core branch portion, and FIG. FIG. 1D is a cross-sectional view seen from the direction of arrow CC in FIG.
It is a figure which shows the arrangement | sequence relationship of the single core code seen from the direction of arrow DD of (C).

In FIG. 1A, reference numeral 28 denotes a tape cord, 29 denotes a single-core cord, 30 denotes an optical connector connected to one end of the single-core cord, and 31 denotes a single-branch. FIG.
(B), FIG. 1 (C) and FIG. 1 (D)
Numeral 11 is a four-core tape coating, 12 is a single-core single-core coating, 13 is a single-core optical fiber coating, 1
Reference numerals 4 and 15 denote bare optical fibers from which the coating has been removed, 16 denotes a cord jacket of a tape cord, 17 denotes a cord jacket of a single-core cord, 18 and 19 are tensile members, 20 is a fusion splicing part, and 21 is a fusion splicing part. Protection member, 22 is a hot melt adhesive, 23, 24
Reference numerals a and 24b denote heat-shrinkable members, reference numeral 25 denotes a protective tube, and reference numerals 26 and 27 denote rubber boots.

Tape cord 28 in which single core branching is performed
Are prepared in the form of a cord with a pitch of 0.25 mm, that is, a cord pitch, with a tensile strength member 18 vertically attached, or a tape with no sheath 16. You. Then, the cord jacket 16 is removed while leaving the strength member 18 at the end thereof, and the core wire coating and the wire coating at the tip are further removed, thereby exposing the bare optical fiber 14 having a nominal outer diameter of 125 μm.

A plurality of single-core cords 29 are prepared according to the number of branches in a form having a cord jacket 17 with a tensile member 19 longitudinally attached, and an optical connector 30 is previously connected to one end thereof. You. At the other end, the cord jacket 17 is removed leaving the tensile strength member 19, then the single-core wire coating 12 is removed, and the optical fiber wire coating 13 is exposed. 13 is removed to expose the bare optical fiber 15.

The single-core cords 29 for the number of branches are shown in FIG.
As shown in (D), they are assembled so that their outer circumferences are in contact with the circle R. When there are four single-core cords as in the specific example in the figure, they are assembled in two rows and two columns. Each of the optical fiber sheaths 13 from which the cord jacket 17 and the single core sheath 12 have been removed,
They are arranged in a line so as to pass through the center of the circle R. Thereby, each optical fiber can be aligned with almost the same degree of bending. Then, the arrangement pitch of the bare optical fibers 15 of each single-core cord is aligned so as to match the core pitch of the tape cord 28, and the portion aligned in one line of the optical fiber sheath 13 is made of adhesive resin or the like. Be taped.

The use of the above-described single-core cord side tape makes it possible to perform batch fusion splicing using a multi-core batch fusion splicer. The connection end faces of the bare optical fibers 14 and 15 are processed and spliced. The fusion splicing portion 20 and the end portions of the optical fiber sheath 13 and the tape core sheath 11 are covered with a heat-shrinkable member 23 having a hot-melt adhesive 22 inside together with a fusion protection member 21. Thereby, integration of the fusion spliced portion and reinforcement of the connection can be performed.

On the outer surface of the heat-shrinkable member 23, the exposed tensile strength members 18 on the tape cord 28 side are uniformly arranged and attached, and the heat-shrinkable member 24a is put thereon from above, and the tensile strength members 18 It is held and fixed so as to be sandwiched between the contracting members 23 and 24a. Further, on the outer surface of the heat-shrinkable member 24a, the single-core cord 2 which is also exposed and separate
The strength member 19 on the 9th side is uniformly aligned and attached, and the heat-shrinkable member 24b is covered from above.
It is held and fixed so as to be sandwiched between 4a and 24b. The heat treatment of the heat-shrinkable members 24a and 24b may be performed individually or simultaneously.

As described above, by separately holding and fixing the strength members 18 and 19 with the different heat-shrinkable members, it is possible to avoid troublesome work due to the entanglement of both strength members,
Further, the holding of the tensile strength member is ensured, and the strength can be increased. In the present embodiment, a configuration is used in which both the tape cord 28 and the single-core cord 29 have a tensile member. However, the tape cord 28 may not be provided with a tensile member, for example, a tape core may be used. In this case, it goes without saying that the heat-shrinkable member 24a is unnecessary.

Finally, the fusion spliced portion is placed in a protective tube 25, where protection from external force and reinforcement are performed. Rubber boots 26 and 27 are provided at both ends of the protection tube 25 to reduce stress at the portion where the tape cord jacket 16 and the single-core cord jacket 17 are introduced into the protection tube 25. The rubber boots 26 and 27 are preferably passed through the tape cord 16 and the fiber cord 17 before fusion splicing.
In addition, the protective tube 25 may have a shape that can be opened and closed, such as a lunch box type, in addition to the tube shape.

Next, the manufacturing method of the present invention will be described with reference to the flowchart of FIG. Note that the description refers to the reference numerals shown in FIG. First, prior to manufacturing, a tape cord 28 for performing single-core branching and an optical connector 30 are provided.
Are prepared in advance. In the present embodiment, the tape cord has a core wire pitch of 0.25 mm and the nominal diameter of the bare fiber 14 is 125 μm.
m, a single-core cord 29 with four optical connectors 30 is used as a single-core cord for branching.
Use In this single-core cord 29, the outer diameter of the cord jacket 17 is 2 mm, the outer diameter of the single-core coating 12 is 0.9 mm, the outer diameter of the wire coating 13 is 0.25 mm, and the nominal diameter of the bare fiber 15 is 125 μm. Use those. The single-core coating 12 preferably has an outer diameter of 0.4 mm or more. The tape cord and the single-core cord each having a tensile strength member were used.

(Step S1 ') First, the coating for fusion splicing the tape cord 28 and the single-core cord 29 is removed. The cord jacket 16 of the tape cord 28 is removed, and the tensile strength member 18 is separated by removing the cord jacket 16,
Wrap it behind the code. Next, tape core coating 1
1 and the bare optical fiber coating (not shown) are removed, exposing the bare fiber 14 leaving the required length of coating. The exposure of the bare fiber 14 may not be performed in this step but may be performed in the subsequent S3 step.

(Step S1) To remove the coating of the single-core cord 29, removing the cord jacket 17 and folding the strength member 19 backward of the cord are the same as in the case of the tape cord. Next, the single-core covering 12 having an outer diameter of 0.9 mm is removed while leaving the strand covering 13 having an outer diameter of 0.25 mm. Outer diameter 0.
The reason for leaving the 25 mm optical fiber wire coating 18 is that the coated portions are brought into close contact with each other and arranged in a line so as to match the core wire pitch of the bare fiber 14 on the tape cord side, thereby enabling fusion splicing. It is. To remove only the core coating 12 having an outer diameter of 0.9 mm, advanced technology is required, but it has been made possible by improving the coating removing jig.

(Step S2) After the end of the single core cord 29 is removed, a plurality of cords 29 are bundled, and the optical fiber wires 13 are arranged in a line, and this part is taped. For this tape formation, a tape forming jig 40 as shown in FIG. 3 described later is used. By making the portion of the optical fiber coating 13 into a tape, the core wire pitch of the bare fiber 15 is reduced to the bare fiber 1 on the tape cord side.
4 core wire pitches can be matched. Further, the root portion of the cord coating 17 is tied and bound by using a rubber boot 27 or other appropriate means such as adhesion so as to prevent the tape from being broken during handling.

(Steps S3 and S3 ') After the single-core cord is taped, the coating of the optical fiber sheath 13 having an outer diameter of 0.25 mm is removed, and the sheath having a predetermined length is left bare. The optical fiber 15 is exposed. To remove this coating,
A remover used for removing the covering of the tape core wire can be used. Thereafter, the exposed bare optical fiber 15 is exposed.
Is cut to the length required for fusion splicing using a fiber cutter. The bare optical fiber 14 on the tape cord side is similarly cut to a length required for fusion splicing, and an end face treatment is performed as necessary.

At this stage, the heat-shrinkable members 21, 24a and 24b are inserted in advance into the single-core cord side or the tape cord side. Further, a rubber boot 27 attached to the end of the protection tube 25 is fitted in advance on the single core cord side, and the rubber boot 26 is also fitted on the tape cord side. In particular, the rubber boot 27 also has a function of bundling discrete single-core cords 29 into one, and may be fitted at the stage before the tape formation in the S2 step. Furthermore, when the protective tube 25 is formed in a tubular shape, it is preferable that the protective tube 25 is previously fitted on a cord.

(Step S4) After processing necessary for fusion splicing is performed, the tape cord 28 and the single-core cord 29 are set in a known multi-core batch fusion splicing apparatus, and the bare fiber on the tape cord side is set. 14 and bare fiber 15 on the single-core cord side
Are aligned by a centering means such as a V-groove, and the four optical fibers are fusion-spliced at a time.

(Step S5) Since the coating is completely removed from the fusion spliced portion 20, the strength is reduced. Therefore, a fusion protection member 21 is attached to the fusion splicing portion 20 and is surrounded by a heat-shrinkable member 21 fitted and inserted in advance. A hot-melt adhesive 23 is previously applied to the inner surface of the heat-shrinkable member, and the heat-shrinkable member 21 shrinks and the hot-melt adhesive 23 is melted and solidified by heating to reinforce the fusion spliced portion 20. .

(Step S6) After the fusion splicing portion 20 is reinforced, the strength member 18 folded back on the cord jacket 16 is uniformly covered so as to cover the outer surface of the heat-shrinkable member 23. Heat-shrinkable member 24a with the outside fitted in advance
Cover with. Next, the strength member 19 on the single-core cord side is uniformly covered so as to cover the outside of the heat-shrinkable member 24a, and the outside is covered with the heat-shrinkable member 24b fitted in advance. Then, the heat-shrinkable members 23, 24a, and 24b are contracted by heating, the strength member 18 is tightly fitted between the heat-shrink members 23 and 24a, and the strength member 19 is tightly fitted between the heat-shrink members 24a and 24b. Fix it.

Thus, the strength members 18, 19 of the tape cord 28 and the single-core cord 29 can be fixed. Note that by applying a hot-melt adhesive in advance to the inner surfaces of the heat-shrinkable members 24a and 24b, the tensile strength members 18 and 19 may be bonded and integrated to increase the fixing force.

(Step S7) Then, the protective tubes 25, which have been inserted beforehand, are covered so as to surround the entire processing section after the fusion splicing and the processing of the tensile strength members are completed. Mechanical protection is performed by assembling certain rubber boots 26 and 27, and a fusion spliced body 31 shown in FIG.
Complete.

(Step S8) Eventually, the loss of the connection portion,
Manufacturing is completed by measuring mechanical strength, temperature characteristics, and the like, and performing a quality inspection.

Next, an example of the tape forming jig 40 used in the tape forming in the above-mentioned S2 step will be described with reference to FIG. In the figure, reference numeral 41 denotes a support base, and 44 denotes a clamp lid. The support base 41 is provided with a single-core cord storage groove 42 and an optical fiber element wire storage groove 43. The cord accommodating groove 42 is formed so that the distal end portion of the cord jacket 17 having an outer diameter of 2 mm of the single-core cord 29 is accommodated in two steps and two rows (when there are four single-core cords 29). On the outer surface of the cord jacket 17, a strength member 19 is folded back and held together in the groove.

The optical fiber wire storage groove 42 has an outer diameter of 0.9.
The optical fiber strand having the coating 13 having an outer diameter of 0.25 mm from which the single-core coating 12 mm has been removed is formed in a groove shape so as to be closely aligned in a line. Also,
The optical fiber wire accommodating groove 42 is provided so as to be located at the center position where the single-core cords are accommodated in multiple stages, so that the optical fiber wires can be closely aligned with substantially equal and uniform bending.

The clamp lid 44 is hingedly connected to the support base 41 so as to be openable and closable, and clamps the single core cords 29 arranged and stored in the respective grooves. Clamp lid 4
A tongue piece 45 is provided integrally with the tip of the optical fiber 4 and clamps the optical fiber with the tongue piece. The optical fiber wire storage groove 42 has a T
The tape is formed in the area indicated by T.

The clamp cover 44 is closed, and the cord jacket 17 is closed.
After the wire covering 13 is clamped, the taped area T
The excess resin is removed by pouring an adhesive resin into the surface of the optical fiber and patting the upper surface with a spatula, and the optical fiber coatings 13 of the aligned optical fibers are bonded and integrated to form a tape. Thereby, at least this taped portion can be made to match the core wire pitch of the tape code.

Although the specific example of the above-described single-fiber branch is for a tape cord, the present invention can also be applied to a case where a single-fiber branch is performed directly from a tape core wire having neither a cord jacket nor a tensile strength member. In this case, the tape core may be protected by separately covering the tape core with a protective tube and vertically attaching a tensile member.

[0040]

As described above, according to the structure of the present invention, the following effects can be obtained. 1. By using a single-core cord on the single-core branch side, compared to the case of using a ribbon cord, the fusion splicing part for connection with the tape core wire should be easily made near the base of the single-core cord. And the shape of the single core branching portion can be reduced in size. Also, single-core cords having different colors of the jacket can be combined, and can be used for identifying connection to the communication terminal.

2. The workability can be improved by separating the heat-shrinkable member for reinforcing the fusion splicing and the heat-shrinkable member for fixing the tensile strength member. In addition, this makes it possible to reliably reinforce the fusion splicing and to securely fix the tensile strength member.

3. Coated outer diameter 0.25mm for single core cord
Outer diameter of 0.4 mm between the optical fiber having the
By using the one provided with the above coating, the strain of the optical fiber is strengthened, the workability at the single-branch portion and the optical connector connection, the stability is excellent, and the reliability without disconnection can be improved. .

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing an embodiment of the present invention, FIG. 1 (A) is a view showing an overall outline, and FIG. 1 (B) is a partially enlarged sectional view of a fusion spliced body. 1 (C) is a cross-sectional view of the same, and FIG. 1 (D) is a view showing an arrangement relationship of single-core cords.

FIG. 2 is a flowchart showing a manufacturing method according to the present invention.

FIG. 3 is a diagram showing an example of a tape-making jig used in the present invention.

FIG. 4 is a diagram illustrating an example of a conventional single core branch.

FIG. 5 is a diagram showing another example of a conventional single-fiber branch.

[Explanation of symbols]

Reference numeral 11: tape core coating, 12: single core coating, 13: optical fiber coating, 14, 15: bare optical fiber, 16, 1
7: Cord jacket, 18, 19: Tensile body, 20: Fusion connection part, 21: Fusion protection member, 22: Hot melt adhesive, 23, 24a, 24b: Heat shrink member, 25: Protection tube, 26 , 27 ... rubber boots, 28 ... tape cord, 2
9: Single core cord, 30: Optical connector, 31: Single core branch, 40: Tape jig.

Claims (4)

[Claims] 1. A plurality of single-core optical fiber cords each having an optical connector connected to one end thereof, and a multi-core optical fiber tape cord or a tape cord are connected by fusion splicing. At the fusion splicing portion, the optical fiber strands of the core optical fiber cord are aligned and taped in a line so as to match the core pitch of the multi-core optical fiber tape cord or tape core, and are spliced in a taped form. A tensile strength member is provided in at least one of the single-core optical fiber cord and the multi-core optical fiber tape cord or tape core wire,
An optical fiber cord having a single-branch portion of a multi-core optical fiber, wherein the tensile member is disposed outside a heat shrinkable member for protecting the fusion splicing member, and is individually fixed by another heat shrinkable member. . 2. The single-core optical fiber cord and the multi-core optical fiber tape cord each include a tensile member, and the tensile members are individually fixed by different heat-shrinkable members. An optical fiber cord having a single-fiber branch portion of the multi-fiber optical fiber according to claim 1. 3. The single-core optical fiber cord has a nominal diameter of 1.
A coating having an outer diameter of 0.25 mm is provided on a 25 μm bare optical fiber, and a coating having an outer diameter of 0.4 mm or more is provided between the coating and the jacket. 2. The tape core wire according to claim 1, wherein a bare optical fiber having a nominal diameter of 125 [mu] m and an optical fiber having a coating having an outer diameter of 0.25 mm are arranged at a core wire pitch of 0.25 mm. 3. An optical fiber cord having a single-fiber branch portion of the multi-fiber optical fiber according to 2. 4. A plurality of single-core optical fiber cords each having an optical connector connected to one end thereof, and a multi-core optical fiber tape cord or a tape core wire are prepared, and the other ends of the plurality of single-core optical fiber cords are provided. The multi-core optical fiber tape cord or tape is exposed and exposed in a line so as to match the core pitch of the tape core wire, and thereafter, the coating removal and end face treatment required for fusion splicing are performed, The end of the multi-core optical fiber tape cord on the single-branch side was subjected to coating removal and end face treatment necessary for fusion splicing, and the single-core optical fiber cord and the multi-core optical fiber tape cord were fusion-spliced. Thereafter, the fusion spliced portion is reinforced by a heat-shrinkable member, and thereafter, the strength members of the single-core optical fiber cord and the multi-core optical fiber tape cord are fixed by a heat-shrinkable member different from the heat-shrinkable member, and maintained. A method for manufacturing an optical fiber cord having a single-fiber branch portion of a multi-fiber optical fiber, comprising attaching a protective body.