Optical fiber ribbon and method for manufacturing optical fiber ribbon

Abstract

Provided is an optical fiber ribbon (100) comprising a plurality of coated optical fibers (10) including a first coated optical fiber (10A) and a second coated optical fiber (10B) adjacent to the first coated optical fiber (10A), wherein the first coated optical fiber (10A) and the second coated optical fiber (10B) are intermittently connected in the direction in which they extend, the optical fiber ribbon (100) satisfying Formula (1) wherein: δi is the maximum value of the slack length of the first coated optical fiber (10A) in the width direction of the optical fiber ribbon (100), δi+1 is the maximum value of the slack length of the second coated optical fiber (10B) in the width direction, and di, i+1 is the distance in the width direction between the center of the first coated optical fiber (10A) and the center of the second coated optical fiber (10B) when slack does not occur in the first coated optical fiber (10A) and the second coated optical fiber (10B).　Formula (1): δi+δi+1<di, i+1

Description

Optical fiber ribbon and method of manufacturing the same

[0001] This disclosure relates to an optical fiber ribbon and a method for manufacturing the same. This application claims priority to Japanese Application No. 2024-146632, filed on August 28, 2024, and incorporates by reference all of the contents of said Japanese application.

[0002] Conventionally, optical fiber ribbons including a plurality of optical fiber core wires have been developed. For example, Patent Document 1 discloses an intermittent optical fiber ribbon in which a plurality of optical fiber core wires are arranged in a parallel row, and in which connected portions and non-connected portions are intermittently formed between adjacent optical fiber core wires.

[0003] Japanese Patent Application Publication No. 2014-228688

[0004] The optical fiber ribbon of the present disclosure includes a plurality of optical fibers, each having a first optical fiber and a second optical fiber adjacent to the first optical fiber, and is an optical fiber ribbon in which the first optical fiber and the second optical fiber are intermittently connected in an extending direction, and the maximum value of the slack length of the first optical fiber in the width direction of the optical fiber ribbon is defined as δ ｉ and the maximum value of the slack length of the second optical fiber in the width direction is δ ｉ＋１ and the distance in the width direction between the center of the first optical fiber and the center of the second optical fiber when no slack occurs in the first optical fiber and the second optical fiber is d ｉ，ｉ＋１ When this is the case, the formula (1) is satisfied.

[0005] FIG. 1 is a diagram illustrating an optical fiber ribbon according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view of the optical fiber ribbon illustrated in FIG. 1. FIG. 3 is a diagram illustrating a slack portion of the first optical fiber indicated by the dashed line A1 in FIG. 1. FIG. 4 is a table illustrating experimental results of investigating the correspondence between the excess length ratio of each of the first optical fiber and the second optical fiber illustrated in FIG. 1 and the presence or absence of overlap between the first optical fiber and the second optical fiber. FIG. 5 is a diagram illustrating an optical fiber ribbon according to a first modified example of the first embodiment of the present disclosure. FIG. 6 is a cross-sectional view of the optical fiber ribbon illustrated in FIG. 5. FIG. 7 is a diagram illustrating an optical fiber ribbon according to a second modified example of the first embodiment of the present disclosure. FIG. 8 is a cross-sectional view of the optical fiber ribbon illustrated in FIG. 7. FIG. 9 is a diagram illustrating an optical fiber ribbon according to a third modified example of the first embodiment of the present disclosure. FIG. 10 is a diagram illustrating an optical fiber ribbon according to a fourth modified example of the first embodiment of the present disclosure. FIG. 11 is a cross-sectional view of the optical fiber ribbon illustrated in FIG. 10. FIG. 12 is a diagram illustrating an optical fiber ribbon according to a second embodiment of the present disclosure. FIG. 13 is a cross-sectional view of the optical fiber ribbon illustrated in FIG. 12. Figure 14 is a table showing the results of an experiment investigating the correspondence between the excess length ratio of each of the second optical fiber core wire and the third optical fiber core wire shown in Figure 12 and whether or not there is overlap between the second optical fiber core wire and the third optical fiber core wire.

[0006] [Problem to be Solved by the Invention] However, there is a possibility that slack may occur in some of the optical fibers. If an optical fiber ribbon is made using optical fibers with such slack, adjacent optical fibers may overlap each other during bulk fusion splicing or the like, which may result in damage to some of the optical fibers.

[0007] An object of the present disclosure is to provide an optical fiber ribbon and a method for manufacturing the optical fiber ribbon that can prevent adjacent optical fiber core wires from overlapping each other.

[0008] Effect of the Invention According to the present disclosure, it is possible to prevent adjacent optical fibers from overlapping each other.

[0009] <Description of Embodiments of the Present Disclosure> First, embodiments of the present disclosure will be listed and described. An optical fiber ribbon according to an embodiment of the present disclosure is an optical fiber ribbon including a plurality of optical fibers, each having a first optical fiber and a second optical fiber adjacent to the first optical fiber, the first optical fiber and the second optical fiber being intermittently connected in an extending direction of the first optical fiber, wherein a maximum value of a slack length of the first optical fiber in a width direction of the optical fiber ribbon is δ ｉ and the maximum value of the slack length of the second optical fiber in the width direction is δ ｉ＋１ and the distance in the width direction between the center of the first optical fiber and the center of the second optical fiber when no slack occurs in the first optical fiber and the second optical fiber is d ｉ，ｉ＋１ An optical fiber ribbon that satisfies formula (1) when

[0010] This configuration can prevent adjacent optical fibers from overlapping each other.

[0011] (2) In the optical fiber ribbon of (1) above, an adhesive resin that connects adjacent optical fiber cores may be intermittently applied to one of the two parallel surfaces formed by arranging the plurality of optical fiber cores in parallel.

[0012] With this configuration, in an optical fiber ribbon in which adhesive resin is intermittently provided on one of the two parallel surfaces, it is possible to prevent adjacent optical fibers from overlapping each other.

[0013] (3) In the optical fiber ribbon of (1) above, the optical fiber ribbon may include a plurality of sub-ribbons, each having two or more of the optical fiber cores, and the adhesive resin may be intermittently applied between adjacent sub-ribbons on one of two parallel surfaces formed by arranging the sub-ribbons in parallel.

[0014] With this configuration, in an optical fiber ribbon in which adhesive resin is intermittently provided on one of the two parallel surfaces, overlapping of the optical fiber core wires of each sub-ribbon can be prevented.

[0015] (4) In the optical fiber ribbon of (1) above, on one of the two parallel surfaces formed by arranging a plurality of the optical fiber core wires in parallel, an adhesive resin connecting adjacent optical fiber core wires may be continuously applied in a line shape so as to move back and forth in the width direction of the parallel surface.

[0016] This configuration makes it possible to prevent adjacent optical fiber cores from overlapping in an intermittent optical fiber ribbon in which adhesive resin is continuously applied in a line on one of two parallel surfaces formed by arranging multiple optical fiber cores in parallel.

[0017] (5) In the optical fiber ribbon of (1) above, the optical fiber ribbon may include a plurality of sub-ribbons, each having two or more of the optical fiber core wires, and on one of the two parallel surfaces formed by arranging the plurality of sub-ribbons in parallel, an adhesive resin connecting adjacent optical fiber core wires may be continuously applied in a line shape so as to move back and forth in the width direction of the parallel surface.

[0018] With this configuration, in an intermittent optical fiber ribbon consisting of multiple cores in which adhesive resin is continuously provided in a line on one of the two parallel surfaces, overlapping of the optical fiber cores of each sub-ribbon can be prevented.

[0019] (6) In the optical fiber ribbon of (1) above, an adhesive resin may be applied to the entire optical fiber ribbon, and the adhesive resin between adjacent optical fiber cores may be intermittently removed.

[0020] With this configuration, in an optical fiber ribbon in which adhesive resin is applied to the entirety of multiple optical fiber cores and the adhesive resin between adjacent optical fiber cores is intermittently removed, overlapping of adjacent optical fiber cores can be prevented.

[0021] (7) In the optical fiber ribbon according to any one of (2) to (5) above, the adhesive resin may be applied until it reaches the other of the two parallel surfaces.

[0022] With this configuration, in an optical fiber ribbon in which adhesive resin is intermittently provided from one parallel surface to the other parallel surface, overlapping of adjacent optical fibers can be prevented.

[0023] An optical fiber ribbon according to another embodiment of the present disclosure is (8) an optical fiber ribbon including a first optical fiber, a second optical fiber adjacent to the first optical fiber, a third optical fiber adjacent to the second optical fiber, and a fourth optical fiber adjacent to the third optical fiber, wherein the first optical fiber, the second optical fiber, the third optical fiber, and the fourth optical fiber are different from one another, and in an extending direction of the optical fiber ribbon, a position of a first adhesive resin intermittently connecting the first optical fiber and the second optical fiber, a position of a second adhesive resin intermittently connecting the second optical fiber and the third optical fiber, and a position of a third adhesive resin intermittently connecting the third optical fiber and the fourth optical fiber are different from one another, and a maximum value of a slack length of the second optical fiber in a width direction of the optical fiber ribbon is δ ｉ and the maximum value of the slack length of the third optical fiber in the width direction is δ ｉ＋１ When no slack occurs in the second optical fiber core and the third optical fiber core, the distance in the width direction between the center of the second optical fiber core and the center of the third optical fiber core is defined as d ｉ，ｉ＋１ The longer of the distances between the first adhesive resin and the second adhesive resin in the extending direction is defined as S ｉ and the longer of the distances between the second adhesive resin and the third adhesive resin in the extending direction is S ｉ＋１ The shorter of the distance between the end of the first adhesive resin in the extending direction and the end of the second adhesive resin in the extending direction is defined as G ｉ，ｉ＋１ When this is the case, the formula (2) and the formula (3) are satisfied.

[0024] This configuration makes it possible to prevent overlapping of adjacent optical fiber core wires in an optical fiber ribbon in which the positions at which the slack length between adjacent optical fiber core wires are at their maximum are likely to be shifted from each other in the direction in which the optical fiber ribbon extends.

[0025] (9) A method for manufacturing an optical fiber ribbon according to an embodiment of the present disclosure is a method for manufacturing an optical fiber ribbon including a first optical fiber and a second optical fiber adjacent to the first optical fiber, the first optical fiber and the second optical fiber being intermittently connected in an extending direction, wherein a maximum value of a slack length of the first optical fiber in a width direction of the optical fiber ribbon is set to δ ｉ and the maximum value of the slack length of the second optical fiber in the width direction is δ ｉ＋１ and the distance in the width direction between the center of the first optical fiber and the center of the second optical fiber when no slack occurs in the first optical fiber and the second optical fiber is d ｉ，ｉ＋１ In this case, the excess length ratios of the first optical fiber and the second optical fiber are controlled so as to satisfy the formula (1).

[0026] By using this method, it is possible to prevent adjacent optical fibers from overlapping each other.

[0027] Another embodiment of the present disclosure provides a method for manufacturing an optical fiber ribbon, which is (10) a method for manufacturing an optical fiber ribbon including a first optical fiber, a second optical fiber adjacent to the first optical fiber, a third optical fiber adjacent to the second optical fiber, and a fourth optical fiber adjacent to the third optical fiber, wherein the first optical fiber, the second optical fiber, the third optical fiber, and the fourth optical fiber are different from one another, and in an extending direction of the optical fiber ribbon, a position of a first adhesive resin intermittently connecting the first optical fiber and the second optical fiber, a position of a second adhesive resin intermittently connecting the second optical fiber and the third optical fiber, and a position of a third adhesive resin intermittently connecting the third optical fiber and the fourth optical fiber are different from one another, and a maximum value of a slack length of the second optical fiber in a width direction of the optical fiber ribbon is set to δ ｉ and the maximum value of the slack length of the third optical fiber in the width direction is δ ｉ＋１ When no slack occurs in the second optical fiber core and the third optical fiber core, the distance in the width direction between the center of the second optical fiber core and the center of the third optical fiber core is defined as d ｉ，ｉ＋１ The longer of the distances between the first adhesive resin and the second adhesive resin in the extending direction is defined as S ｉ and the longer of the distances between the second adhesive resin and the third adhesive resin in the extending direction is S ｉ＋１ The shorter of the distance between the end of the first adhesive resin in the extending direction and the end of the second adhesive resin in the extending direction is defined as G ｉ，ｉ＋１ A method for manufacturing an optical fiber ribbon, wherein the excess length ratios of the second optical fiber and the third optical fiber are controlled so as to satisfy equations (2) and (3) when

[0028] This method makes it possible to prevent overlapping of adjacent optical fiber core wires in an optical fiber ribbon in which the positions at which the slack length between adjacent optical fiber core wires are at their maximum are likely to be shifted from each other in the direction in which the optical fiber ribbon extends.

[0029] <Details of the Embodiments of the Present Disclosure> Specific examples of the optical fiber ribbon of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0030] [First embodiment] (Overall configuration of optical fiber ribbon) Fig. 1 is a diagram showing an optical fiber ribbon 100 according to a first embodiment of the present disclosure. Fig. 2 is a cross-sectional view of the optical fiber ribbon 100 shown in Fig. 1. More specifically, Fig. 2(A) is a cross-sectional view taken along line IIA-IIA shown in Fig. 1, Fig. 2(B) is a cross-sectional view taken along line IIB-IIB shown in Fig. 1, and Fig. 2(C) is a cross-sectional view taken along line IIC-IIC shown in Fig. 1.

[0031] 1 and 2, an optical fiber ribbon 100 includes a plurality of optical fiber core wires 10 arranged in parallel and an adhesive resin 20 connecting the plurality of optical fiber core wires 10. In Fig. 1, as an example, the optical fiber ribbon 100 includes 12 optical fiber core wires 10. Hereinafter, the direction in which the optical fiber core wires 10 extend is defined as the Y direction, and the direction in which the plurality of optical fiber core wires 10 are arranged is defined as the X direction. Each optical fiber core wire 10 is, for example, a single-core fiber (SCF).

[0032] The adhesive resin 20 is applied so as to intermittently connect adjacent coated optical fibers 10. For example, the adhesive resin 20 is applied intermittently using a dispenser to one of two parallel surfaces formed by arranging a plurality of coated optical fibers 10 side by side, between the outer peripheries of adjacent coated optical fibers 10, and then hardened. Note that the adhesive resin 20 may be applied until it reaches the other of the two parallel surfaces.

[0033] As shown by the dashed line A1 in Fig. 1 and (C) in Fig. 2 , the optical fiber 10 is relatively susceptible to displacement because adjacent optical fibers 10 are not fixed between the adhesive resins 20 in the Y direction. If the length of the displaceable optical fiber 10 is longer than a specified value, slack may occur in the optical fiber 10. If the slack in the optical fiber 10 is large, adjacent optical fibers 10 may overlap during a bulk fusion splicing operation, which may result in damage to a portion of the optical fiber 10. Therefore, in the optical fiber ribbon 100 according to the present disclosure, the amount of slack in the optical fiber 10 is adjusted as described below so that adjacent optical fibers 10 do not overlap.

[0034] (Adjusting slack in optical fiber cores) Here, as shown by dashed line A1 in Figure 1 and (C) in Figure 2, it is assumed that slack occurs in the first optical fiber core 10A, which is the optical fiber core 10, and the second optical fiber core 10B, which is the optical fiber core 10.

[0035] The maximum value of the slack length of the first optical fiber 10A in the width direction (X direction) of the optical fiber ribbon 100 is defined as δ ｉ The maximum value of the slack length of the second optical fiber 10B in the X direction is δ ｉ＋１ 2B, when no slack occurs in the first optical fiber 10A and the second optical fiber 10B, the distance in the X direction between the center of the first optical fiber 10A and the center of the second optical fiber 10B is defined as d ｉ，ｉ＋１ Let's say.

[0036] In such an optical fiber ribbon 100, if the following formula (1) is satisfied, the first optical fiber core wire 10A and the second optical fiber core wire 10B can be prevented from overlapping, making them less likely to break during bulk fusion splicing operations, etc.

[0037] Next, using Figs. 1 to 3, δ in Equation (1) ｉ and δ ｉ＋１3 is a diagram for explaining the slack portion of the first optical fiber 10A indicated by the dashed line A1 in FIG.

[0038] Here, as shown in FIG. 2C, the distance between the center of the first optical fiber 10A when no slack occurs in the first optical fiber 10A and the center of the first optical fiber 10A when slack occurs is defined as Δ ｉ 1, the distance between adjacent adhesive resins 20 in the Y direction is defined as S.

[0039] 3, when a slack that describes a part of a sine curve occurs in the extra length portion of the first optical fiber 10A, the amplitude of the sine curve shown by the solid line is greater than the distance Δ ｉ In addition, when the sine curve shown by the solid line is approximated by a triangle shown by the dashed line, Δ ｉ By using ', Δ ｉ = 0.9 × Δ ｉ ' can be expressed as

[0040] The length of the solid line shown in FIG. ｉ Then, the excess length ratio e of the first optical fiber 10A is ｉ = (L ｉ The length of the hypotenuse of the triangle shown by the dashed line in FIG. ｉ / 2, and L ｉ / 2=S / 2×(1+e ｉ ) Then, by using Pythagoras' theorem, the following equation (4) holds.

[0041] Furthermore, by using the formula (4), the maximum value δ of the slack length of the first optical fiber 10A can be calculated as the following formula (5). ｉ The same calculation method can be used for the second optical fiber 10B to calculate the maximum value δ of the slack length of the second optical fiber 10B. ｉ＋１ can be calculated.

[0042] Then, in the manufacturing process of the optical fiber ribbon 100, δ calculated using the formula (5) ｉ and δ ｉ＋１ The excess length ratio e of the first optical fiber 10A and the second optical fiber 10B is determined so that the formula (1) holds when the formula (1) is applied to the formula (1). ｉ For example, by managing the feeding control of the first optical fiber 10A and the second optical fiber 10B so that there is no deviation when applying the adhesive resin 20, the excess length ratio e of the first optical fiber 10A and the second optical fiber 10B can be controlled. ｉ This makes it possible to prevent the first optical fiber 10A and the second optical fiber 10B from overlapping each other.

[0043] (Experimental Example) FIG. 4 shows the relationship between the extra length ratio e of each of the first optical fiber 10A and the second optical fiber 10B shown in FIG. ｉ , e ｉ＋１ 10B and the presence or absence of overlap between the first optical fiber 10A and the second optical fiber 10B.

[0044] Here, the excess length ratio e of each of the first optical fiber 10A and the second optical fiber 10B is ｉ , e ｉ＋１ By changing the thickness of the coated optical fiber 10A, seven types of optical fiber ribbons 100 were manufactured. Then, for each optical fiber ribbon 100, a portion of the coating film covering the plurality of coated optical fibers 10 was removed to check whether the first coated optical fiber 10A and the second coated optical fiber 10B overlapped with each other.

[0045] In all seven types of optical fiber ribbons 100, the distance S between the adhesive resins 20 is 20 mm. In addition, in all seven types of optical fiber ribbons 100, the distance d in the X direction between the center of the first optical fiber 10A and the center of the second optical fiber 10B when no slack occurs in the first optical fiber 10A and the second optical fiber 10B is 20 mm. ｉ，ｉ＋１ = 0.25 mm.

[0046] In the table shown in Fig. 4, when the first optical fiber 10A and the second optical fiber 10B do not overlap, it is marked as "A." On the other hand, when the first optical fiber 10A and the second optical fiber 10B overlap, it is marked as "C."

[0047] As shown in "1" in the table of FIG. 4, the excess length ratio e ｉ = 0.00%, and the excess length ratio e ｉ＋１ = 0.00%, the maximum value δ of the slack length of the first optical fiber 10A in the X direction ｉ and the maximum value δ of the slack length of the second optical fiber 10B. ｉ＋１ The sum of δ ｉ +δ ｉ＋１ In this case, the total δ ｉ +δ ｉ＋１ is the distance d ｉ，ｉ＋１ In the optical fiber ribbon 100 including such a first optical fiber 10A and a second optical fiber 10B, the first optical fiber 10A and the second optical fiber 10B do not overlap each other.

[0048] Similarly, as shown in "2" to "7" in the table of FIG. 4, the excess length ratio e ｉ , and the extra length ratio e of the second optical fiber 10B ｉ＋１ When the overlap between the optical fiber core wires was checked by changing the number, the results were as shown in the table. In the cases of "2", "4", and "5", the first optical fiber core wire 10A and the second optical fiber core wire 10B did not overlap, but in the cases of "3", "6", and "7", the first optical fiber core wire 10A and the second optical fiber core wire 10B partially overlapped.

[0049] The control of the excess length ratio e so that the above formula (1) holds is not limited to the first optical fiber 10A and the second optical fiber 10B, but is performed for each optical fiber 10 in the optical fiber ribbon 100. The experimental results shown in the table in Fig. 4 confirmed that such control of the excess length ratio e of each optical fiber 10 can prevent adjacent optical fibers 10 in the optical fiber ribbon 100 from overlapping with each other.

[0050] (Variation 1) Fig. 5 is a diagram showing an optical fiber ribbon 200 according to Variation 1 of the first embodiment of the present disclosure. Fig. 6 is a cross-sectional view of the optical fiber ribbon 200 shown in Fig. 5. More specifically, Fig. 6(A) is a cross-sectional view taken along the VIA-VIA line shown in Fig. 5, Fig. 6(B) is a cross-sectional view showing a state in which it is assumed that slack occurs in a portion of the optical fiber core 210 shown in Fig. 6(A), Fig. 6(C) is a cross-sectional view taken along the VIC-VIC line shown in Fig. 5, and Fig. 6(D) is a cross-sectional view taken along the VID-VID line shown in Fig. 5.

[0051] 5 and 6 , the optical fiber ribbon 200 includes a plurality of sub-ribbons 231, each having, for example, two coated optical fibers 210. Adjacent coated optical fibers 210 included in a sub-ribbon 231 are connected to each other over their entire lengths. The optical fiber ribbon 200 shown in Fig. 5 includes, as an example, six sub-ribbons 231, which are arranged in a plane along the width direction (the X direction shown in Fig. 5 ).

[0052] The number of optical fiber cores 210 included in each of the sub-ribbons 231 is not limited to two, but may be three or more.

[0053] Optical fiber ribbon 200 also includes adhesive resin 220 that connects adjacent sub-ribbons. More specifically, adhesive resin 220 is applied intermittently between adjacent sub-ribbons on one of two parallel surfaces formed by arranging six sub-ribbons 231 in parallel. Note that adhesive resin 220 may be applied until it reaches the other of the two parallel surfaces.

[0054] In such an optical fiber ribbon 200, as shown in Fig. 6B, slack may occur in at least one of the adjacent sub-ribbons, which may cause adjacent coated optical fibers 210 to overlap with each other. For this reason, in the optical fiber ribbon 200, similarly to the optical fiber ribbon 100 shown in Fig. 1, the δ calculated using equation (5) ｉ and δ ｉ＋１The excess length ratio e of each optical fiber 210 is controlled so that equation (1) holds when the following equation is applied to the optical fiber 210. This makes it possible to prevent adjacent optical fibers 210 from overlapping with each other.

[0055] (Modification 2) Figure 7 is a diagram showing an optical fiber ribbon 300 according to Modification 2 of the first embodiment of the present disclosure. Figure 8 is a cross-sectional view of the optical fiber ribbon 300 shown in Figure 7. More specifically, (A) of Figure 8 is a cross-sectional view taken along line VIIIA-VIIIA shown in Figure 7, (B) of Figure 8 is a cross-sectional view taken along line VIIIB-VIIIB shown in Figure 7, and (C) of Figure 8 is a cross-sectional view taken along line VIIIC-VIIIC shown in Figure 7.

[0056] 7 and 8, the optical fiber ribbon 300, like the optical fiber ribbon 100 shown in Fig. 1, includes a plurality of parallel-arranged optical fibers 310 and an adhesive resin 320 connecting the plurality of parallel-arranged optical fibers 310. The adhesive resin 320 is continuously applied in a line shape to one of two parallel surfaces formed by arranging the plurality of parallel-arranged optical fibers 310, so as to travel back and forth in the width direction of the parallel surface (the X direction shown in Fig. 6). Note that the adhesive resin 320 may be applied until it reaches the other of the two parallel surfaces.

[0057] In such an optical fiber ribbon 300, slack may occur in the optical fibers 310, which may cause adjacent optical fibers 310 to overlap with each other. For this reason, in the optical fiber ribbon 300, similarly to the optical fiber ribbon 100 shown in FIG. 1, the δ calculated using the formula (5) ｉ and δ ｉ＋１ The excess length ratio e of each optical fiber 310 is controlled so that equation (1) holds when the following equation is applied to the optical fiber 310. This makes it possible to prevent adjacent optical fibers 310 from overlapping with each other.

[0058] (Variation 3) Fig. 9 is a diagram showing an optical fiber ribbon 400 according to Variation 3 of the first embodiment of the present disclosure. The optical fiber ribbon 400 includes a plurality of sub-ribbons 411, each having two optical fibers 410. Adjacent optical fibers 410 included in a sub-ribbon 411 are connected to each other over their entire lengths. The optical fiber ribbon 400 shown in Fig. 9 includes, as an example, six sub-ribbons 411, which are arranged in a plane along the width direction (the X direction shown in Fig. 9 ).

[0059] The number of optical fiber cores 410 included in each of the sub-ribbons 411 is not limited to two, but may be three or more.

[0060] The optical fiber ribbon 400 also includes adhesive resin 420 that connects adjacent sub-ribbons 411. The adhesive resin 420 is applied continuously in a line on one of two parallel surfaces formed by arranging a plurality of sub-ribbons 411 in parallel, so that the adhesive resin 420 moves back and forth in the width direction of the parallel surface (the X direction shown in FIG. 9 ). Note that the adhesive resin 420 may be applied until it reaches the other of the two parallel surfaces.

[0061] In such an optical fiber ribbon 400, slack may occur in the optical fibers 410, which may cause adjacent optical fibers 410 to overlap with each other. For this reason, in the optical fiber ribbon 400, similarly to the optical fiber ribbon 100 shown in FIG. 1, the δ calculated using the formula (5) ｉ and δ ｉ＋１ The excess length ratio e of each optical fiber 410 is controlled so that equation (1) holds when the following equation is applied to the optical fiber 410. This makes it possible to prevent adjacent optical fibers 410 from overlapping with each other.

[0062] (Modification 4) Figure 10 is a diagram showing an optical fiber ribbon 500 according to Modification 4 of the first embodiment of the present disclosure. Figure 11 is a cross-sectional view of the optical fiber ribbon 500 shown in Figure 10. More specifically, Figure 11(A) is a cross-sectional view taken along line XIA-XIA shown in Figure 10, Figure 11(B) is a cross-sectional view taken along line XIB-XIB shown in Figure 10, and Figure 11(C) is a cross-sectional view taken along line XIC-XIC shown in Figure 10.

[0063] 10 and 11 , the optical fiber ribbon 500, similar to the optical fiber ribbon 100 shown in Fig. 1 , includes a plurality of parallel-arranged optical fiber cores 510 and an adhesive resin 520 connecting the plurality of optical fiber cores 510. The adhesive resin 520 is applied to the entirety of the plurality of optical fiber cores 510, and then intermittently removed along the Y direction in the portions between the adjacent optical fiber cores 510 to form slit portions 521.

[0064] In such an optical fiber ribbon 500, slack may occur in the optical fibers 510, which may cause adjacent optical fibers 510 to overlap with each other. For this reason, in the optical fiber ribbon 500, similarly to the optical fiber ribbon 100 shown in FIG. 1, the δ calculated using the formula (5) ｉ and δ ｉ＋１ The excess length ratio e of each optical fiber 510 is controlled so that equation (1) holds when the following equation is applied to the optical fiber 510. This makes it possible to prevent adjacent optical fibers 510 from overlapping with each other.

[0065] [Second embodiment] (Overall configuration of optical fiber ribbon) Fig. 12 is a diagram showing an optical fiber ribbon 600 according to a second embodiment of the present disclosure. Fig. 13 is a cross-sectional view of the optical fiber ribbon 600 shown in Fig. 12. More specifically, Fig. 13(A) is a cross-sectional view taken along line XIIIA-XIIIA shown in Fig. 12, Fig. 13(B) is a cross-sectional view taken along line XIIIB-XIIIB shown in Fig. 12, and Fig. 13(C) is a cross-sectional view taken along line XIIIC-XIIIC shown in Fig. 12.

[0066] Referring to Figures 12 and 13, the optical fiber ribbon 600, similar to the optical fiber ribbon 100 shown in Figure 1, comprises a plurality of parallel-arranged optical fiber core wires 610 and an adhesive resin 620 connecting these plurality of optical fiber core wires 610.

[0067] The adhesive resin 620 is applied so as to intermittently connect adjacent coated optical fibers 610. As described above, the adhesive resin 20 (see FIG. 1) of the optical fiber ribbon 100 according to the first embodiment is applied intermittently to one of the two parallel surfaces formed by arranging the plurality of coated optical fibers 10 in parallel. In contrast, the adhesive resin 620 of the optical fiber ribbon 600 is applied until it reaches the other of the two parallel surfaces formed by arranging the plurality of coated optical fibers 610 in parallel, as shown in FIGS. 13A and 13C .

[0068] 12, one of the multiple optical fiber cores 610 is designated as a first optical fiber core 610A, and the optical fiber core 610 adjacent to the first optical fiber core 610A is designated as a second optical fiber core 610B. Also, the optical fiber core 610 adjacent to the second optical fiber core 610B and different from the first optical fiber core 610A is designated as a third optical fiber core 610C, and the optical fiber core 610 adjacent to the third optical fiber core 610C and different from the second optical fiber core 610B is designated as a fourth optical fiber core 610D.

[0069] Furthermore, the adhesive resin 620 connecting the first optical fiber core 610A and the second optical fiber core 610B is referred to as the first adhesive resin 620A, the adhesive resin 620 connecting the second optical fiber core 610B and the third optical fiber core 610C is referred to as the second adhesive resin 620B, and the adhesive resin 620 connecting the third optical fiber core 610C and the fourth optical fiber core 610D is referred to as the third adhesive resin 620C.

[0070] In this case, the first adhesive resin 620A, the second adhesive resin 620B, and the third adhesive resin 620C are applied at different positions in the Y direction, which is the direction in which the optical fiber core 610 extends.

[0071] (Adjusting Slack in Optical Fiber) In the above-described configuration, assume that slack occurs in the second optical fiber 610B and the third optical fiber 610C. In this case, the position A2 at which the slack length of the second optical fiber 610B in the width direction of the optical fiber ribbon 600 (the X direction shown in FIG. 12 ) is maximum is near the center of the longer distance between the first adhesive resin 620A and the second adhesive resin 620B, as shown by the dashed line in FIG. 12 .

[0072] In contrast, in the third optical fiber 610C, the position A3 where the slack length of the third optical fiber 610C in the X direction is maximum is near the center of the longer distance between the second adhesive resin 620B and the third adhesive resin 620C, as shown by the dashed line in Figure 12. In other words, the positions where the slack length is maximum in the Y direction differ between adjacent optical fiber 610. In such an optical fiber ribbon 600, the slack of the optical fiber 610 is adjusted as described below.

[0073] Here, the length of the slack of the second optical fiber 610B at the position A2 (i.e., the maximum value of the slack of the second optical fiber 610B) is defined as δ ｉ The length of the slack of the third optical fiber 610C at the position A3 (i.e., the maximum value of the slack of the third optical fiber 610C) is set to δ ｉ＋１ In addition, when no slack occurs in the second optical fiber 610B and the third optical fiber 610C, the distance in the X direction between the center of the second optical fiber 610B and the center of the third optical fiber 610C is defined as d ｉ，ｉ＋１ Let's say.

[0074] As shown in FIG. 12, the longer distance between the first adhesive resin 620A and the second adhesive resin 620B in the Y direction is defined as S ｉ The longer distance between the second adhesive resin 620B and the third adhesive resin 620C is defined as S ｉ＋１ The shorter distance between the end of the first adhesive resin 620A in the Y direction and the end of the second adhesive resin 620B in the Y direction is defined as G ｉ，ｉ＋１ Let's say.

[0075] In this case, the slack length of the second optical fiber 610B at the position A3 can be expressed as follows:

[0076] The slack length of the third optical fiber 610C at the position A2 can be expressed as follows:

[0077] That is, when the following formulas (2) and (3) are satisfied, the second optical fiber 610B and the third optical fiber 610C can be prevented from overlapping with each other.

[0078] Therefore, in the optical fiber ribbon 600, δ calculated using the above-mentioned formula (5) ｉ and δ ｉ＋１ The excess length ratio e of each optical fiber 610 is controlled so that when Equation (2) and Equation (3) are applied to Equation (2) and Equation (3), the excess length ratio e of each optical fiber 610 is set to be valid. This makes it possible to prevent adjacent optical fibers 610 from overlapping with each other.

[0079] (Experimental Example) FIG. 14 shows the relationship between the extra length ratio e of the second optical fiber 610B and the third optical fiber 610C shown in FIG. ｉ , e ｉ＋１ 10B and the presence or absence of overlap between the second optical fiber core 610B and the third optical fiber core 610C.

[0080] Here, the extra length ratio e of each of the second optical fiber core 610B and the third optical fiber core 610C is ｉ , e ｉ＋１ By changing the thickness of the optical fiber ribbon 600, seven types of optical fiber ribbons 600 were manufactured. Then, for each optical fiber ribbon 600, a portion of the coating film covering the multiple optical fiber cores 610 was removed to check whether the second optical fiber cores 610B and the third optical fiber cores 610C overlapped with each other.

[0081] In all of the seven types of optical fiber ribbons 600, the distance S between the adhesive resins 620 is ｉ , S ｉ＋１In addition, for all seven types of optical fiber ribbons 600, when no slack occurs in the second optical fiber 610B and the third optical fiber 610C, the distance d ｉ，ｉ＋１ = 0.25 mm. The shorter distance G between the end of the first adhesive resin 620A in the Y direction and the end of the second adhesive resin 620B in the Y direction is ｉ，ｉ＋１ = 20 mm.

[0082] 14, when the second optical fiber core 610B and the third optical fiber core 610C do not overlap, it is marked as "A." On the other hand, when the second optical fiber core 610B and the third optical fiber core 610C overlap, it is marked as "C."

[0083] As shown in "1" in the table of FIG. 14, the excess length ratio e ｉ = 0.00%, and the excess length ratio e ｉ＋１ In this case, the maximum value δ of the slack length of the second optical fiber 610B is ｉ =0.00 mm, and the maximum value of the slack length δ of the third optical fiber core 610C ｉ＋１ = 0.00 mm. In other words, the left side of equation (2) is 0.00 mm, and the distance d ｉ，ｉ＋１ Furthermore, the left side of equation (3) is 0.00 mm, and the distance d ｉ，ｉ＋１ In the optical fiber ribbon 600 including such second optical fiber cores 610B and third optical fiber cores 610C, the second optical fiber cores 610B and the third optical fiber cores 610C do not overlap each other.

[0084] Similarly, as shown in "2" to "7" in the table of FIG. 14, the excess length ratio e ｉ and the excess length ratio e of the third optical fiber core 10B ｉ＋１When the number was changed and the overlap between the optical fiber cores was checked, the results were as shown in the table. In the cases of "2", "4", and "5", the second optical fiber core 610B and the third optical fiber core 610C did not overlap, but in the cases of "3", "6", and "7", the second optical fiber core 610B and the third optical fiber core 610C partially overlapped.

[0085] The control of the excess length ratio e so that the above formulas (2) and (3) hold is not limited to the second optical fiber 610B and the third optical fiber 610C, but is performed for each optical fiber 610 in the optical fiber ribbon 600. The experimental results in the table shown in Fig. 14 confirmed that by controlling the excess length ratio e of each optical fiber 610 in this way, it is possible to prevent adjacent optical fibers 610 in the optical fiber ribbon 600 from overlapping each other.

[0086] Although the present disclosure has been described above based on specific embodiments, the present disclosure is not limited to these examples, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0087] 10, 210, 310, 410, 510, 610 Optical fiber core wire 10A, 610A First optical fiber core wire 10B, 610B Second optical fiber core wire 20, 220, 320, 420, 520, 620 Adhesive resin 100, 200, 300, 400, 500, 600 Optical fiber ribbon 231, 411 Sub-ribbon 521 Slit portion 610C Third optical fiber core wire 610D Fourth optical fiber core wire 620A First adhesive resin 620B Second adhesive resin 620C Third adhesive resin

Claims

1. An optical fiber ribbon including a plurality of optical fiber core wires, each having a first optical fiber core wire and a second optical fiber core wire adjacent to the first optical fiber core wire, in which the first optical fiber core wires and the second optical fiber core wires are intermittently connected in the direction in which they extend, wherein the maximum value of the slack length of the first optical fiber core wire in the width direction of the optical fiber ribbon is δ ｉ and the maximum value of the slack length of the second optical fiber in the width direction is δ ｉ＋１ The distance in the width direction between the center of the first optical fiber and the center of the second optical fiber when no slack occurs in the first optical fiber and the second optical fiber is defined as d ｉ，ｉ＋１ An optical fiber ribbon that satisfies formula (1) when 2. An optical fiber ribbon as described in claim 1, in which an adhesive resin that connects adjacent optical fiber cores is intermittently applied to one of the two parallel surfaces formed by arranging multiple optical fiber cores in parallel.

3. The optical fiber ribbon according to claim 1, wherein the optical fiber ribbon comprises a plurality of sub-ribbons, each having two or more of the optical fiber cores, and an adhesive resin is intermittently applied between adjacent sub-ribbons on one of two parallel surfaces formed by arranging the sub-ribbons in parallel.

4. An optical fiber ribbon as described in claim 1, wherein, on one of the two parallel surfaces formed by arranging a plurality of the optical fiber core wires in parallel, adhesive resin connecting adjacent optical fiber core wires is continuously applied in a line shape so as to move back and forth in the width direction of the parallel surface.

5. The optical fiber ribbon according to claim 1, wherein the optical fiber ribbon comprises a plurality of sub-ribbons, each having two or more of the optical fiber cores, and on one of two parallel surfaces formed by arranging the plurality of sub-ribbons in parallel, an adhesive resin connecting adjacent optical fiber cores is continuously applied in a line shape so as to move back and forth in the width direction of the parallel surface.

6. An optical fiber ribbon according to claim 1, wherein an adhesive resin is applied to the entire optical fiber ribbon, and the adhesive resin between adjacent optical fibers is intermittently removed.

7. An optical fiber ribbon according to any one of claims 2 to 5, wherein the adhesive resin is applied until it reaches the other of the two parallel surfaces.

8. An optical fiber ribbon including a first optical fiber, a second optical fiber adjacent to the first optical fiber, a third optical fiber adjacent to the second optical fiber, and a fourth optical fiber adjacent to the third optical fiber, wherein the first optical fiber, the second optical fiber, the third optical fiber, and the fourth optical fiber are different from one another, and in the extending direction of the optical fiber ribbon, a position of a first adhesive resin intermittently connecting the first optical fiber and the second optical fiber, a position of a second adhesive resin intermittently connecting the second optical fiber and the third optical fiber, and a position of a third adhesive resin intermittently connecting the third optical fiber and the fourth optical fiber are different from one another, and a maximum value of a slack length of the second optical fiber in the width direction of the optical fiber ribbon is defined as δ ｉ The maximum value of the slack length of the third optical fiber in the width direction is defined as δ ｉ＋１ When no slack occurs in the second optical fiber core and the third optical fiber core, the distance in the width direction between the center of the second optical fiber core and the center of the third optical fiber core is defined as d ｉ，ｉ＋１ The longer of the distances between the first adhesive resin and the second adhesive resin in the extending direction is defined as S ｉ The longer of the distances between the second adhesive resin and the third adhesive resin in the extending direction is defined as S ｉ＋１ The shorter of the distance between the end of the first adhesive resin in the extending direction and the end of the second adhesive resin in the extending direction is defined as G ｉ，ｉ＋１ An optical fiber ribbon that satisfies formula (2) and formula (3) when 9. A method for manufacturing an optical fiber ribbon including a first optical fiber core wire and a second optical fiber core wire adjacent to the first optical fiber core wire, in which the first optical fiber core wire and the second optical fiber core wire are intermittently connected in the direction in which they extend, wherein the maximum value of the slack length of the first optical fiber core wire in the width direction of the optical fiber ribbon is δ ｉ and the maximum value of the slack length of the second optical fiber in the width direction is δ ｉ＋１ The distance in the width direction between the center of the first optical fiber and the center of the second optical fiber when no slack occurs in the first optical fiber and the second optical fiber is defined as d ｉ，ｉ＋１ a method for manufacturing an optical fiber ribbon, the method controlling the excess length ratio of the first optical fiber and the second optical fiber so as to satisfy formula (1) when 10. A method for manufacturing an optical fiber ribbon including a first optical fiber, a second optical fiber adjacent to the first optical fiber, a third optical fiber adjacent to the second optical fiber, and a fourth optical fiber adjacent to the third optical fiber, wherein the first optical fiber, the second optical fiber, the third optical fiber, and the fourth optical fiber are different from one another, and in the extending direction of the optical fiber ribbon, a position of a first adhesive resin intermittently connecting the first optical fiber and the second optical fiber, a position of a second adhesive resin intermittently connecting the second optical fiber and the third optical fiber, and a position of a third adhesive resin intermittently connecting the third optical fiber and the fourth optical fiber are different from one another, and a maximum value of a slack length of the second optical fiber in the width direction of the optical fiber ribbon is defined as δ ｉ The maximum value of the slack length of the third optical fiber in the width direction is defined as δ ｉ＋１ When no slack occurs in the second optical fiber core and the third optical fiber core, the distance in the width direction between the center of the second optical fiber core and the center of the third optical fiber core is defined as d ｉ，ｉ＋１ The longer of the distances between the first adhesive resin and the second adhesive resin in the extending direction is defined as S ｉ The longer of the distances between the second adhesive resin and the third adhesive resin in the extending direction is defined as S ｉ＋１ The shorter of the distance between the end of the first adhesive resin in the extending direction and the end of the second adhesive resin in the extending direction is defined as G ｉ，ｉ＋１ A method for manufacturing an optical fiber ribbon, wherein the excess length ratios of the second optical fiber and the third optical fiber are controlled so as to satisfy equations (2) and (3) when

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