Optical fiber ribbon core, mold, and method for manufacturing optical fiber ribbon core

Abstract

An optical fiber ribbon core wire has a plurality of optical fiber core wires and a common cladding layer integrally covering the plurality of optical fiber core wires. A plurality of intermittent link portions are formed between every prescribed number of 2 or more of the optical fiber core wires in the length direction of the plurality of optical fiber core wires, alternately with first link portions formed of the common cladding layer and non-link portions formed of notches opened in the common cladding layer. A plurality of continuous link portions are formed of second link portions formed of the common cladding layer between the optical fiber core wires other than the optical fiber core wires in which the plurality of intermittent link portions are formed. The plurality of optical fiber core wires is an even number. The plurality of intermittent link portions has a central intermittent link portion in the central portion in the width direction of the optical fiber ribbon core wire. The plurality of continuous link portions has adjacent continuous link portions between each pair of optical fiber core wires at both pairs of optical fiber core wires sandwiching the central portion in the width direction. The adjacent continuous link portions have a thickness that is thicker than the thickness of the central intermittent link portion and thicker than the thickness of the continuous link portions other than the adjacent continuous link portions.

Description

Technical Field

[0001] This disclosure relates to optical fiber ribbon cores, molds for manufacturing optical fiber ribbon cores, and methods for manufacturing optical fiber ribbon cores using the molds.

[0002] This application claims priority based on Japanese Application No. 2020-169681, filed on October 7, 2020, the entire contents of which are incorporated herein by reference. Background Technology

[0003] Patent Document 1 discloses a method for manufacturing an intermittently connected fiber ribbon core (also known as an intermittent ribbon core) capable of being separated into two fiber cores. The document describes that in the intermittent ribbon core, connecting and non-connecting portions are alternately formed in the length direction, adjacent fiber cores are intermittently connected to each other, and periodic cuts penetrating in the thickness direction are made by a cutting roller.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-74644 Summary of the Invention

[0007] One aspect of this disclosure relates to an optical fiber ribbon core comprising: a plurality of optical fiber cores; and a common cladding layer covering the plurality of optical fiber cores and integrating them into one unit. The optical fiber ribbon core has: a plurality of intermittent connecting portions, wherein, along the length direction of the plurality of optical fiber cores, a first connecting portion and a non-connecting portion are alternately formed between every two or more predetermined numbers of the optical fiber cores, the first connecting portion being constituted by the common cladding layer, and the non-connecting portion being formed by a cut in the common cladding layer; and a plurality of continuous connecting portions, wherein, along the length direction, the plurality of... A second connection formed by the common cladding layer is continuously formed between the optical fiber cores other than those between the intermittent connection sections. The plurality of optical fiber cores are an even number. The plurality of intermittent connection sections have a central intermittent connection section at the center of the optical fiber core in the width direction. At the two pairs of optical fiber cores sandwiching the central part in the width direction, the plurality of continuous connection sections have adjacent continuous connection sections between each pair of optical fiber cores. The thickness of the adjacent continuous connection section is thicker than the thickness of the central intermittent connection section and thicker than the thickness of the continuous connection sections other than the adjacent continuous connection section.

[0008] One aspect of this disclosure relates to a mold for manufacturing optical fiber ribbon cores. The mold has multiple holes through which multiple parallel optical fiber cores pass, the number of which is even. Adjacent holes are connected, and multiple holes are formed in the connecting portion of adjacent holes to sandwich the parallel surfaces of the multiple optical fiber cores. Each hole has: a first opposing portion formed at the center of the width direction of the optical fiber ribbon core; and a second opposing portion formed to the left and right of the center of the width direction of the optical fiber ribbon core. The ratio of the opposing distance of the first opposing portion to the opposing distance of the second opposing portion is 1:1.1 or more.

[0009] One aspect of this disclosure relates to a method for manufacturing optical fiber ribbon cores using the mold. Attached Figure Description

[0010] Figure 1 This is a perspective view of an optical fiber ribbon core wire according to one embodiment of the present disclosure.

[0011] Figure 2 This is a cross-sectional view of an optical fiber ribbon core according to one embodiment of this disclosure.

[0012] Figure 3 This is a diagram illustrating a method for manufacturing an optical fiber ribbon core according to an embodiment of the present disclosure.

[0013] Figure 4 This is a cross-sectional view of a mold according to one embodiment of this disclosure.

[0014] Figure 5 It is used for explanation Figure 4 The diagram shows the dimensions of the mold. Detailed Implementation

[0015] [The technical problem this disclosure aims to solve]

[0016] In the manufacture of fiber optic ribbon cores, when the ribbon resin, which serves as the common cladding layer, is applied, the shear stress in the central portion of the fiber optic ribbon core is greater than that at the ends, and the resin pressure in the central portion is also higher than that at the ends. Resin tends to flow into the central portion, widening the gap between the fibers therein, resulting in a tendency for the thickness of the common cladding layer in the central portion to be greater than that at the ends in the width direction. Therefore, when manufacturing intermittent ribbon cores by making cuts at predetermined locations between the fiber cores, as in Patent Document 1, it is difficult to stably make these cuts between the fiber cores in the central portion of the width direction. The difference between the resin pressure at the ends and the central portion of the fiber optic ribbon core increases with the increased manufacturing speed. To achieve higher manufacturing speeds for fiber optic ribbon cores, it is desirable to implement measures to prevent the thickness increase between the fiber cores after making cuts.

[0017] The purpose of this disclosure is to provide fiber optic ribbon cores, molds, and methods for manufacturing intermittent ribbon cores.

[0018] [Description of embodiments of this disclosure]

[0019] First, the contents of the embodiments of this disclosure will be described.

[0020] The fiber ribbon core involved in this disclosure

[0021] (1) It comprises: multiple optical fiber cores; and a common cladding layer covering the multiple optical fiber cores to integrate them, wherein each optical fiber core has: multiple intermittent connection portions, wherein in the length direction of the multiple optical fiber cores, a first connection portion and a non-connection portion are alternately formed between every two or more predetermined number of optical fiber cores, the first connection portion being constituted by the common cladding layer, and the non-connection portion being formed by a cut in the common cladding layer; and multiple continuous connection portions, wherein in the length direction, the multiple intermittent connection portions are formed. A second connection portion, consisting of the common cladding layer, is continuously formed between the fiber cores other than those between the fiber cores. The plurality of fiber cores are an even number. Each of the plurality of intermittent connections has a central intermittent connection portion at the center of the fiber core in the width direction. At the two pairs of fiber cores sandwiching the central connection portion in the width direction, the plurality of continuous connections have adjacent continuous connections between each pair of fiber cores. The thickness of the adjacent continuous connections is greater than the thickness of the central intermittent connection portion and also greater than the thickness of the continuous connections other than the adjacent continuous connections. This structure prevents the thickness of the central portion from increasing, making it easier to make the cut.

[0022] The mold (2) disclosed herein is used to manufacture optical fiber ribbon cores. The mold has multiple holes through which multiple parallel optical fiber cores pass, the number of which is even. Adjacent holes are connected, and a plurality of holes are formed between the connected portions of adjacent holes, sandwiching the parallel surfaces of the multiple optical fiber cores. Each hole has: a first opposing portion formed at the center of the width direction of the optical fiber ribbon core; and a second opposing portion formed to the left and right of the center of the width direction of the optical fiber ribbon core. The ratio of the opposing distance of the first opposing portion to the opposing distance of the second opposing portion is 1:1.1 or more. This mold, relative to the optical fiber ribbon core covered with a common cladding layer, has a first opposing portion with a cut and a second opposing portion without a cut. Since the ratio of the opposing distance of the first opposing portion to the opposing distance of the second opposing portion is 1:1.1 or more, resin is more easily retained in the second opposing portion compared to the portion of the first opposing portion which is opposed with a narrower interval. Therefore, at the first opposing portion, the thickness of the common cladding layer between the optical fiber cores can be prevented from increasing, and when manufacturing intermittent band cores, it is easy to make a cut in the center.

[0023] (3) In one aspect of the mold disclosed herein, a third opposing portion is provided between the plurality of holes. The third opposing portion is a portion other than the first opposing portion and the second opposing portion, formed in every two or more predetermined numbers of the connecting portions. The ratio of the opposing distance of the third opposing portion to the opposing distance of the second opposing portion is 1:1.03 or more. This mold has a third opposing portion that, like the second opposing portion, does not have a cut. Since the ratio of the opposing distance of the third opposing portion to the opposing distance of the second opposing portion is 1:1.03 or more, resin is more likely to remain in the second opposing portion compared to the portion of the third opposing portion that is opposed at a narrow interval. Therefore, compared to the portion of the first opposing portion, resin is more likely to accumulate in the portion of the second opposing portion. Consequently, in the portion of the first opposing portion, the thickness of the common cladding layer between the optical fiber cores can be formed more reliably and thinner.

[0024] (4) In one aspect of the fiber ribbon core manufacturing method disclosed herein, it is a method for manufacturing fiber ribbon cores using the aforementioned mold. By using the mold, it is possible to form a thinner common cladding layer between specified fiber cores. Therefore, when manufacturing intermittent ribbon cores, it is easy to make cuts between the fiber cores of the fiber ribbon core.

[0025] [The Effects of This Disclosure]

[0026] Based on the above, it is possible to provide an optical fiber ribbon core suitable for manufacturing intermittent ribbon cores, a mold for manufacturing the optical fiber ribbon core, and a method for manufacturing the optical fiber ribbon core using the mold.

[0027] [Details of the embodiments of this disclosure]

[0028] Hereinafter, specific examples of the optical fiber ribbon core, mold, and manufacturing method of the optical fiber ribbon core according to embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the following examples, which are shown through the claims and are intended to include all modifications with the same meaning and scope as the claims. Furthermore, the present disclosure includes the content after combining any of the multiple embodiments, as long as multiple embodiments can be combined. It should be noted that in the following description, the same reference numerals used in different figures indicate the same configuration, and their description may sometimes be omitted.

[0029] Figure 1 This is a perspective view of an optical fiber ribbon core wire according to one embodiment of the present disclosure. Figure 2 This is a cross-sectional view of an optical fiber ribbon core according to one embodiment of this disclosure. The optical fiber ribbon core 10 is obtained by arranging (side-by-side) a plurality of even-numbered optical fiber cores 11 (11a to 11l) in a parallel row in a contacting state, and integrating the outer surfaces, including the upper and lower side-by-side surfaces, over the entire length of the ribbon through a common cladding layer 12. Figure 1 and Figure 2 The image shows an optical fiber ribbon core with the optical fiber cores 11 in contact with each other, but the optical fiber cores 11 can also be separated without contacting each other.

[0030] The optical fiber core 11 is a single-core optical fiber. The optical fiber core 11 has a glass fiber 13, a protective cladding 14, and a coloring layer 15. The glass fiber 13 has a core 13a and a cladding 13b, with an outer diameter of 125 μm. The protective cladding 14 covers the outer periphery of the glass fiber 13 and is, for example, an acrylic resin. The coloring layer 15 covers the outer periphery of the protective cladding 14 and has an outer diameter of approximately 255 μm. It should be noted that the outer diameters of the glass fiber 13 and the optical fiber core 11 are not limited to 125 μm and 255 μm respectively; they can also be finer, for example, approximately 100 μm and 200 μm respectively. In this embodiment, the common cladding layer 12 is a UV-curable resin, but it can also be a thermoplastic resin, a thermosetting resin, or the like. Furthermore, the protective cladding 14 can also consist of two layers.

[0031] The fiber ribbon core 10 of this embodiment is an intermittent ribbon core 10 in which a common cladding layer 12 periodically has cuts 17 extending through the thickness direction between every two or more fiber ribbon cores 11. Specifically, the fiber ribbon cores 11 with cuts 17 form intermittent connection portions 31 along the entire length of the fiber ribbon core 10, where first connection portions 18 and non-connection portions are alternately formed. The first connection portions 18 are composed of the common cladding layer 12, while the non-connection portions lack the common cladding layer 12 and are formed by cuts 17 extending through the thickness direction. Furthermore, the fiber ribbon cores 11 without cuts 17 form continuous connection portions 32 along the entire length of the fiber ribbon core 10, where second connection portions 19 composed of the common cladding layer 12 are continuously formed. Since the fiber ribbon core 10 consists of an even number of fibers, the fiber ribbon cores 11 are located at the center of the fiber ribbon core 10 in the width direction.

[0032] exist Figure 1 and Figure 2 In the example shown, a notch 17 is provided between every two fiber cores 11. More specifically, notches 17 are provided on the common cladding layer 12 between fiber cores 11b and 11c, between fiber cores 11d and 11e, between fiber cores 11f and 11g, between fiber cores 11h and 11i, and between fiber cores 11j and 11k. Therefore, multiple intermittent connections 31 are formed between the fiber cores between fiber cores 11b and 11c, between fiber cores 11d and 11e, between fiber cores 11f and 11g, between fiber cores 11h and 11i, and between fiber cores 11j and 11k. Therefore, multiple continuous connection parts 32 are respectively formed between optical fiber cores 11a and 11b, between optical fiber cores 11c and 11d, between optical fiber cores 11e and 11f, between optical fiber cores 11g and 11h, between optical fiber cores 11i and 11j, and between optical fiber cores 11k and 11l.

[0033] On the common cladding layer 12 between adjacent optical fiber cores 11, recesses 16a, 16aa, and 16c formed by the indentation of the common cladding layer 12 and a flat portion 16b that is flat in the width direction of the common cladding layer 12 are formed. The flat portion 16b is formed at the two pairs of optical fiber cores (one pair of optical fiber cores 11e and 11f, and one pair of optical fiber cores 11g and 11h) sandwiching the central portion of the optical fiber ribbon core in the width direction, forming an adjacent continuous connection portion 32' between each pair of optical fiber cores (between optical fiber cores 11e and 11f, and between optical fiber cores 11g and 11h). The recess 16aa is formed at the central intermittent connection portion 31' of the central portion of the optical fiber ribbon core in the width direction (between optical fiber cores 11f and 11g). Recess 16a is formed in the intermittent connection portion 31 (between fiber cores 11b and 11c, between fiber cores 11d and 11e, between fiber cores 11h and 11i, and between fiber cores 11j and 11k) outside the central portion (between fiber cores 11f and 11g) in the width direction of the fiber core. Recess 16c is formed in the continuous connection portion 32 (between fiber cores 11a and 11b, between fiber cores 11c and 11d, between fiber cores 11i and 11j, and between fiber cores 11k and 11l) outside the left and right adjacent portions of the central portion in the width direction.

[0034] In this embodiment, the flat portion 16b is thicker than the recessed portion 16aa and also thicker than the recessed portion 16c. The recessed portion 16a is thicker than the recessed portion 16aa. The recessed portion 16a may be thicker or thinner than the recessed portion 16c.

[0035] It should be noted that the thickness of the intermittent connecting portion 31 (recess 16aa) indicates the thickness of the connecting portion in the intermittent connecting portion where a common covering layer exists.

[0036] It should be noted that, in the case of an optical fiber ribbon core 10 with an outer diameter of 200 μm, the thickness d1 of the intermittent connection portion 31 at the center of the width direction of the optical fiber ribbon core 10 is preferably 160–180 μm. In the case of an optical fiber ribbon core 10 with an outer diameter of 250 μm, the thickness d1 of the intermittent connection portion 31 at the center of the width direction of the optical fiber ribbon core 10 is preferably 200–220 μm.

[0037] In this embodiment, the thickness (thickness of the flat portion 16b) d2 ​​of the continuous connection portion 32 at the left and right adjacent positions of the central portion of the fiber optic ribbon core 10 in the width direction is thicker than the thickness (thickness of the recess 16aa) d1 of the intermittent connection portion 31 at the central portion of the fiber optic ribbon core 10 in the width direction, and is also thicker than the thickness (thickness of the recess 16c) d3 of the continuous connection portion 32 at the portion other than the left and right adjacent positions of the central portion of the fiber optic ribbon core 10 in the width direction.

[0038] Generally, if the manufacturing speed of the fiber ribbon core is high, there is a tendency for the cladding between the fiber cores in the central part to be thicker than that between the fiber cores at the ends in the width direction. However, in the two pairs of fiber cores sandwiching the central part in the width direction of the fiber ribbon core 10, the thickness d2 of the adjacent continuous connection portion 32' between each pair of fiber cores without the notch 17 is thicker than the thickness d1 of the central intermittent connection portion 31' with the notch 17, i.e., the central part in the width direction of the fiber ribbon core 10, and thicker than the thickness d3 of the continuous connection portions 32 outside the left and right adjacent (adjacent continuous connection portions 32') in the width direction of the central part. By forming such a structure, even if the shear stress in the central part increases, it is possible to prevent the thickness d1 of the central intermittent connection portion 31' in the central part of the fiber ribbon core 10 in the width direction from increasing. Furthermore, when manufacturing the intermittent ribbon core, it is easy to make a notch between the fiber cores 11 in the central part.

[0039] Next, the method for manufacturing the fiber ribbon core according to the embodiments of this disclosure will be described. Figure 3 This is a diagram illustrating a method for manufacturing an optical fiber ribbon core according to embodiments of this disclosure. Additionally, Figure 4 and Figure 5 This is a cross-sectional view of a mold according to one embodiment of the present disclosure. The fiber optic ribbon core manufacturing apparatus includes a supply device 100. Within the supply device 100 are N (12 in this embodiment) spools 101-112 corresponding to the number of fiber optic ribbon cores 10, N adjusting rollers 101a-112a, and a guide roller 120. Fiber optic cores 11 are wound onto each spool 101-112. The fiber optic cores 11 are drawn from each spool 101-112, subjected to tension of tens of gf by the adjusting rollers 101a-112a, and arranged on an alignment surface as they pass through the guide roller 120. The fiber optic cores 11 are further gathered by the overhead guide roller 130 and sent to a coating apparatus 200.

[0040] The optical fiber core 11 is inserted through the coating apparatus 200 and pulled from the downstream side with a specified tension. Thus, the inserted optical fiber core 11 is guided by the guide nozzle 210 into the desired arrangement and sent to the mold 220. Inside the mold 220, as... Figure 1 The UV-curable resin of the common cladding layer 12 shown is applied around the parallel optical fiber cores 11. UV-curable resin is supplied from a pressurized resin tank 230. The 12 optical fiber cores 11 coated with UV-curable resin are cured by UV irradiation in a UV irradiation device 240. The cured UV-curable resin becomes the common cladding layer 12, forming a 12-core optical fiber ribbon core 10.

[0041] The fiber ribbon core 10, cured by ultraviolet radiation from the ultraviolet irradiation device 240, is fed to the winding device 330 with a spool via the guide roller 250, the delivery winch 310, and the winding tension control roller 320, and then via the intermittent processing device 400. The intermittent processing device 400, for example, to form the intermittent connection portion 31 of the fiber ribbon core 10, makes a periodic cut in the common cladding layer 12 between predetermined fiber cores 11 of the fiber ribbon core 10, through the thickness direction, using a cutting roller (not shown). In the winding device 330, the intermittent fiber ribbon core 10 is wound onto the spool via a guide. The overall winding tension of the fiber ribbon core 10 is, for example, tens to hundreds of gf.

[0042] Manufacturing like this Figure 1 The fiber ribbon core 10 is illustrated, but the coating apparatus 200 may also coat it with a thermoplastic resin instead of a UV-curable resin as the ribbon resin forming the common coating layer 12. In this case, the coating apparatus 200 includes an extruder for extruding the thermoplastic resin and a cooling device for cooling the extruded resin. In either case, curing the resin as quickly as possible after passing through the die 220 is effective in maintaining the shape of the fiber ribbon core 10.

[0043] Next, mold 220 will be described. For example... Figure 4As shown, the mold 220 of this embodiment has, for example, 12 holes 221 (221a to 221l) through which 12 optical fiber cores 11 pass, and adjacent holes 221 are connected. The number of holes is even. Multiple hole gaps are formed at the connecting portions of adjacent holes 221, with parallel surfaces sandwiching multiple optical fiber cores. It should be noted that hole gaps refer to the interval at the connecting portions of adjacent holes 221. Each hole gap has a first opposing portion 222a-222a, a second opposing portion 222b-222b, and a third opposing portion 222c-222c. The first opposing portions 222a-222a are formed at the center portion of the optical fiber core 10 in the width direction. The second opposing portions 222b-222b are opposite each other at intervals wider in the thickness direction than the first opposing portions 222a-222a, and are formed to the left and right of the center portion of the optical fiber core 10 in the width direction. The third opposing portions 222c-222c are formed in the central portion of the fiber ribbon core 10 in the width direction and its left and right adjacent portions (excluding the portions other than the first opposing portions 222a-222a and the second opposing portions 222b-222b) in a predetermined number of connections other than every two. Through the mold 220, in the fiber ribbon core covered with the common cladding layer 12, the portion passing through the first opposing portions 222a-222a becomes the central intermittent connection portion 31', the portion passing through the second opposing portions 222b-222b becomes the adjacent continuous connection portion 32', and the portion passing through the third opposing portions 222c-222c becomes the continuous connection portion 32.

[0044] In this embodiment, between hole 221f and hole 221g, such as Figure 5 As shown, a first opposing portion 222a-222a with the shortest opposing distance a is formed, and a second opposing portion 222b-222b with the longest opposing distance b is formed between holes 221e and 221f and between holes 221g and 221h. In addition, for example, between holes 221a and 221b, between holes 221c and 221d, between holes 221i and 221j, and between holes 221k and 221l, a third opposing portion 222c-222c is formed with an opposing distance c longer than the opposing distance a of the first opposing portion 222a-222a and shorter than the opposing distance b of the second opposing portion 222b-222b.

[0045] More specifically, when the outer diameter of the optical fiber core 11 is 200 μm, the ratio of the opposition distance *a* of the first opposing portions 222a-222a to the opposition distance *b* of the second opposing portions 222b-222b is, for example, 1:1.6, and the ratio of the opposition distance *a* of the first opposing portions 222a-222a to the opposition distance *c* of the third opposing portions 222c-222c is, for example, set to 1:1.2. In this case, the ratio of the opposition distance *c* of the third opposing portions 222c-222c to the opposition distance *b* of the second opposing portions 222b-222b is 1:1.33.

[0046] Furthermore, when the outer diameter of the optical fiber core 11 is 250 μm, the ratio of the opposition distance *a* of the first opposing portions 222a-222a to the opposition distance *b* of the second opposing portions 222b-222b is set to, for example, 1:1.8, and the ratio of the opposition distance *a* of the first opposing portions 222a-222a to the opposition distance *c* of the third opposing portions 222c-222c is set to, for example, 1:1.7. In this case, the ratio of the opposition distance *c* of the third opposing portions 222c-222c to the opposition distance *b* of the second opposing portions 222b-222b is 1:1.06.

[0047] Even if the outer diameter of the optical fiber core 11 is 200μm or 250μm, the ratio of the opposition distance 'a' of the first opposing portion 222a-222a to the opposition distance 'b' of the second opposing portion 222b-222b is 1:1.1 or higher. Similarly, even if the outer diameter of the optical fiber core 11 is 200μm or 250μm, the ratio of the opposition distance 'c' of the third opposing portion 222c-222c to the opposition distance 'b' of the second opposing portion 222b-222b is 1:1.03 or higher.

[0048] The mold 220 has a first opposing portion and a second opposing portion relative to the optical fiber cores covered with the common cladding layer. The first opposing portion is the space between holes in the central portion where a cut is formed, and the second opposing portion is the space between adjacent holes in the central portion where no cut is formed. The second opposing portion has a wider spacing than the first opposing portion. Therefore, the resin pressure at the first opposing portion with the narrowest spacing (opposition distance a) is lower than the resin pressure at the second opposing portion with the widest spacing (opposition distance b). Resin is more likely to remain at the second opposing portion with the widest spacing (opposition distance b) compared to the portion with the narrowest spacing (opposition distance a). Therefore, at the portion of the first opposing portion, the thickness of the common cladding layer 12 between the optical fiber cores 11 can be prevented from increasing. Because it can suppress resin bulging at the first opposing portion, when manufacturing the intermittent ribbon core wire, it is easy to make a cut between the optical fiber core wires 11 of the optical fiber ribbon core wire 10 at the thin part of the common cladding layer 12 (the part of the opposing distance a).

[0049] The mold 220 has a third opposing portion without a cut. The opposing distance of the third opposing portion has a narrower interval than that of the second opposing portion. Therefore, compared to the portion of the third opposing portion which is opposed with a narrow interval (opposite distance c), resin is more likely to remain in the portion of the second opposing portion which is opposed with a wide interval (opposite distance b). This further facilitates resin accumulation in the portion of the second opposing portion. Therefore, in the portion of the first opposing portion which is opposed with the narrowest interval (opposite distance a), the thickness of the common cladding layer between the optical fiber cores can be formed more reliably and thinner.

[0050] The above description of the optical fiber ribbon core wires involved in the embodiments of this disclosure refers to the case of 2 or more core wires, but any number other than 2 is acceptable. Similarly, the description of the molds refers to the case of 2 or more molds, but any number other than 2 is acceptable.

[0051] Explanation of reference numerals in the attached figures

[0052] 10…Fiber optic core; 11, 11a~11l…Fiber optic core; 12…Common cladding; 13…Glass fiber; 13a…Core; 13b…Cladding; 14…Protective cladding; 15…Coloring layer; 16a, 16aa, 16c…Recess; 16b…Flat portion; 17…Notch (non-connecting portion); 18…First connecting portion; 19…Second connecting portion; 31…Intermittent connecting portion; 31'…Central intermittent connecting portion; 32…Continuous connecting portion; 32'…Adjacent continuous connecting portion; 100…Supply device ; 101~112…Spindle; 101a~112a…Adjusting roller; 120…Guide roller; 130…Top guide roller; 200…Coating device; 210…Nozzle; 220…Mold; 221, 221a~221l…Hole; 222a, 222b, 222c…Opposing part; 230…Resin tank; 240…Ultraviolet irradiation device; 250…Guide roller; 310…Exit winch; 320…Winding tension control adjusting roller; 330…Winding device; 400…Intermittent processing device.

Claims

1. An optical fiber ribbon core wire, comprising: a plurality of optical fiber core wires; and a common cladding layer covering the plurality of optical fiber core wires to integrate the plurality of optical fiber core wires, the optical fiber ribbon core wire being formed with: a plurality of intermittent connection portions, a first connection portion composed of the common cladding layer and a non-connection portion formed of a cutout provided in the common cladding layer being alternately formed between a prescribed number of the optical fiber core wires of two or more in a length direction of the plurality of optical fiber core wires; and a plurality of continuous connection portions, a second connection portion composed of the common cladding layer being continuously formed between the optical fiber core wires other than the optical fiber core wires in which the plurality of intermittent connection portions are formed in the length direction, the plurality of optical fiber core wires being an even number, the plurality of intermittent connection portions having a central intermittent connection portion in a central portion in a width direction of the optical fiber ribbon core wire, the plurality of continuous connection portions having an adjacent continuous connection portion between each pair of optical fiber core wires at both pairs of optical fiber core wires sandwiching the central portion in the width direction, the adjacent continuous connection portion being thicker than the central intermittent connection portion and thicker than a continuous connection portion other than the adjacent continuous connection portion.

2. A mold for manufacturing the optical fiber ribbon core wire according to claim 1, the mold having a plurality of holes through which a plurality of optical fiber core wires are arranged in parallel, the number of the plurality of holes being an even number, adjacent ones of the plurality of holes being communicated, a plurality of inter-hole portions sandwiching parallel faces of the plurality of optical fiber core wires being formed in a communicated portion of adjacent ones of the plurality of holes, the plurality of inter-hole portions having: a first opposing portion formed in a central portion in a width direction of the optical fiber ribbon core wire; and a second opposing portion formed in left and right adjacent to the central portion in the width direction of the optical fiber ribbon core wire, a ratio of an opposing distance of the first opposing portion to an opposing distance of the second opposing portion being 1:1.1 or more.

3. The mold according to claim 2, wherein the plurality of inter-hole portions have a third opposing portion, which is a portion other than the first opposing portion and the second opposing portion, formed in the communicated portion other than a prescribed number of two or more, a ratio of an opposing distance of the third opposing portion to an opposing distance of the second opposing portion being 1:1.03 or more.

4. A method of manufacturing an optical fiber ribbon core wire using the mold according to claim 2 or 3. ​ ​ ​ ​ ​ ​ ​ ​

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