Optical fiber arrangement method, optical fiber splicing method, production method for optical fiber tape with connector, and intermittently-connected optical fiber tape

Abstract

[Problem] In the work of making a holder hold multiple optical fibers detached and separated into single fibers, handling of the optical fibers is cumbersome and workability is poor. [Solution] An optical fiber arrangement method according to the present disclosure includes: preparing an intermittently connected optical fiber ribbon including a plurality of optical fibers arranged side by side at a first pitch larger than a fiber diameter; reducing a width of the optical fiber ribbon in an interior of a holder by making the holder hold a non-connecting region of the optical fiber ribbon; and arranging the plurality of optical fibers, extending out from the holder, at a second pitch smaller than the first pitch by removing connecting portions in a state where the holder is holding the plurality of optical fibers, the connecting portions connecting the plurality of optical fibers extending out from the holder to each other.

Description

Optical fiber alignment method, optical fiber fusion splicing method, manufacturing method of optical fiber ribbon with connector, and intermittently connected optical fiber ribbon

[0001] The present invention relates to an optical fiber alignment method, an optical fiber fusion splicing method, a method for manufacturing an optical fiber ribbon with connectors, and an intermittently connected optical fiber ribbon.

[0002] Patent Document 1 describes an optical fiber ribbon in which the outer diameter of optical fibers is reduced from 250 μm to 200 μm and optical fibers with an outer diameter of 200 μm are arranged in parallel at a pitch of 250 μm. Patent Document 1 also describes an intermittently connected optical fiber ribbon in which a plurality of parallel optical fibers are intermittently connected.

[0003] Patent No. 5564026

[0004] When a 250 μm-pitch optical fiber ribbon is fused at a mass fusion splicer for a 200 μm pitch, the optical fibers arranged parallel to each other at a 250 μm pitch must be aligned at a 200 μm pitch. In the past, this alignment process involved separating the ends of the 250 μm-pitch optical fiber ribbon into individual fibers and holding the separated optical fibers in a holder for a 200 μm pitch, thereby aligning the optical fibers at a 200 μm pitch. However, the process of holding the separated optical fibers in a holder makes handling the optical fibers inconvenient and reduces workability. This workability issue is not limited to aligning the optical fibers of a 250 μm-pitch optical fiber ribbon at a 200 μm pitch, nor is it limited to mass fusion splicing. It can also occur when aligning the optical fibers of an optical fiber ribbon arranged parallel to a certain pitch (a first pitch) at a different pitch (a second pitch).

[0005] An object of the present invention is to simplify the alignment work of optical fibers.

[0006] The main invention for achieving the above object is an optical fiber alignment method that includes preparing an intermittently connected optical fiber tape having multiple optical fibers arranged in parallel at a first pitch wider than the fiber diameter, narrowing the width of the optical fiber tape inside the holder by holding the non-connected areas of the optical fiber tape with a holder, and aligning the multiple optical fibers extending from the holder at a second pitch narrower than the first pitch by removing the connecting portions that connect the multiple optical fibers extending from the holder while the multiple optical fibers are held in the holder.

[0007] Other features of the present invention will become apparent from the following description and drawings.

[0008] According to the present invention, the alignment work of optical fibers is simplified.

[0009] FIGS. 1A and 1B are explanatory diagrams of an optical fiber ribbon 1 according to a first embodiment. FIG. 2A is a cross-sectional view of two optical fibers 2 connected by a connecting portion 11, showing the location where the connecting portion 11 is formed. FIG. 2B is an explanatory diagram of the connecting portion 11 according to a first modified example. FIG. 2C is an explanatory diagram of the connecting portion 11 according to a second modified example. FIG. 3 is an explanatory diagram of the relationship between the length of the non-connecting region 30 of the optical fiber ribbon 1 and the holder 50. FIG. 4 is a flow chart of a process for batch fusion splicing of a 250 μm-pitch optical fiber ribbon 1 using a fusion splicing device 40 for a 200 μm-pitch optical fiber ribbon. FIGS. 5A and 5B are explanatory diagrams of the non-connecting region 30 being clamped by the holder 50. FIG. 5B is an enlarged view of the B-B cross section of FIG. 5A. FIG. 5C is an explanatory diagram of a holder 50 according to a modified example. FIG. 6A is an explanatory diagram of the removal of the coating from the optical fibers 2 using a coating removal device 60. FIG. 6B is an explanatory diagram of the optical fiber ribbon 1 held by the holder 50 after the coating has been removed. FIG. 7 is an explanatory diagram of the state during fusion splicing. FIG. 8 is a model diagram of the curvature of the Nth fiber. FIG. 9A is an explanatory diagram of a modified example of the optical fiber ribbon 1 of the first embodiment. FIG. 9B is an explanatory diagram of a method of using the mark 8. FIGS. 10A and 10B are explanatory diagrams of the optical fiber ribbon 1 of the second embodiment. FIGS. 11A and 11B are explanatory diagrams of the optical fiber ribbon 1 of the third embodiment. FIG. 12 is an explanatory diagram of the optical fiber ribbon 1 of the third embodiment placed on a holder 50. FIG. 13A is an explanatory diagram of the optical fiber ribbon 1 of the third embodiment held by the holder 50. FIG. 13B is an enlarged view of the B'-B' cross section of FIG. 13A. FIG. 13C is an explanatory diagram of the optical fiber ribbon 1 held by the holder 50 after the coating has been removed. FIG. 14 is an explanatory diagram of the allowable number of connection portions 11 in the second connection section 21B. FIGS. 15A and 15B are explanatory diagrams of the optical fiber ribbon 1 of the fourth embodiment. Fig. 16 is an enlarged view of the XX cross section of Fig. 15B. Fig. 17 is a flow chart of the manufacturing process of the connectorized optical fiber ribbon 1. Fig. 18 is an explanatory diagram of the process of S106 in the fifth embodiment.

[0010] At least the following points will become clear from the description and drawings to be described later.

[0011] The present invention provides an optical fiber alignment method that includes preparing an intermittently connected optical fiber ribbon having a plurality of optical fibers arranged in parallel at a first pitch wider than the fiber diameter, narrowing the width of the optical fiber ribbon inside the holder by holding the non-connected regions of the optical fiber ribbon with a holder, and aligning the plurality of optical fibers extending from the holder at a second pitch narrower than the first pitch by removing connecting portions connecting the plurality of optical fibers extending from the holder while the plurality of optical fibers are held in the holder. Such an optical fiber alignment method simplifies the optical fiber alignment process.

[0012] It is desirable to remove the connecting portions by removing the coatings of the optical fibers extending from the holder while the optical fibers are held in the holder, which allows the removal of the connecting portions of the optical fiber ribbon and the removal of the coatings of the optical fibers to be performed simultaneously, making it easier to align the optical fibers.

[0013] It is desirable that a mark be formed in the non-connected region, and that the optical fiber ribbon and the holder be aligned based on the position of the mark, thereby facilitating the operation of holding the non-connected region of the optical fiber ribbon in the holder.

[0014] The optical fiber ribbon is configured such that a plurality of connecting sections, each having the connecting portions intermittently arranged in the width direction thereof, are arranged longitudinally, and the number of connecting portions arranged in the connecting sections adjacent to the non-connecting regions is preferably smaller than the number of connecting portions arranged in the connecting sections not adjacent to the non-connecting regions. This reduces the influence of the connecting portions when the non-connecting regions of the optical fiber ribbon are clamped by the holder, making it easier to narrow the width of the optical fiber ribbon.

[0015] The optical fiber ribbon includes a plurality of optical fiber sections, each of which has a lengthwise intermittent arrangement of connecting portions, and the optical fiber ribbon includes a non-connecting portion arranged in the lengthwise direction of the optical fiber ribbon, the non-connecting portion being arranged outward in the widthwise direction of the optical fiber ribbon. This arrangement makes it easier for the optical fibers located at the ends of the optical fiber ribbon to be displaced inward, thereby making it easier to narrow the spacing between the optical fibers inside the holder.

[0016] It is desirable that the region where the clamping portion of the holder clamps the optical fiber ribbon be the non-connected region, whereby by holding the non-connected region of the optical fiber ribbon with the holder, it becomes easier to narrow the width of the optical fiber ribbon inside the holder.

[0017] On the other hand, a part of the connecting region in which the connecting portions are provided may be included in the region where the clamping portions of the holder clamp the optical fiber ribbon. In this case, the connecting region is configured by intermittently arranging a plurality of first connecting sections, in which the connecting portions are arranged intermittently in the width direction of the optical fiber ribbon, and second connecting sections arranged adjacent to the non-connecting region in the longitudinal direction, the longitudinal distance between the first connecting sections and the second connecting sections being longer than the longitudinal distance between the first connecting sections and the first connecting sections, and the second connecting section is preferably included in the region where the clamping portions of the holder clamp the optical fiber ribbon. In this way, the second connecting sections clamped by the holder are arranged so as to be biased toward the non-connecting region, making it easier to narrow the distance between the optical fibers not restrained by the connecting portions in the second connecting section.

[0018] The optical fiber aligning method described above clarifies an optical fiber fusion method that includes aligning the plurality of optical fibers extending from the holder at the second pitch narrower than the first pitch, cutting the ends of the plurality of optical fibers extending from the holder and from which the coatings have been removed to a predetermined length while the plurality of optical fibers are held in the holder, and setting the holder in a fusion splicing device while the plurality of optical fibers are held in the holder, and fusing the plurality of optical fibers aligned at the second pitch using the fusion splicing device. Such an optical fiber fusion method simplifies the optical fiber alignment operation, and therefore the fusion operation.

[0019] The optical fiber aligning method described above also clarifies a method for manufacturing a connectorized optical fiber ribbon, which includes aligning the plurality of optical fibers extending from the holder at the second pitch narrower than the first pitch, and then, while the plurality of optical fibers are held in the holder, cutting the ends of the plurality of optical fibers extending from the holder and from which the coating has been removed to a predetermined length, and, while the plurality of optical fibers are held in the holder, inserting the plurality of optical fibers aligned at the second pitch into fiber holes in a ferrule to attach the ends of the plurality of optical fibers to the ferrule. Such a method for manufacturing a connectorized optical fiber ribbon simplifies the alignment of the optical fibers, thereby simplifying the manufacturing process of the connectorized optical fiber ribbon.

[0020] The present invention provides an intermittently connected optical fiber ribbon comprising a plurality of optical fibers arranged in parallel at a pitch wider than the fiber diameter and a plurality of connecting portions connecting two adjacent optical fibers, the plurality of connecting portions being intermittently arranged, the intermittently connected optical fiber ribbon having a connecting region where the plurality of connecting portions are intermittently arranged to connect the plurality of optical fibers, and a non-connecting region between the connecting region and the connecting region where no connecting portions are formed. With such an optical fiber ribbon, the task of aligning a plurality of optical fibers arranged in parallel at a pitch wider than the fiber diameter to a narrower pitch is simplified.

[0021] It is desirable that a mark used for aligning the optical fiber tape with a holder that holds the optical fiber tape be formed in the non-connected region, whereby the optical fiber tape can be aligned with the holder based on the position of the mark, and the non-connected region of the optical fiber tape can be held by the holder.

[0022] The connecting region is configured by a plurality of connecting sections, each having the connecting portions intermittently arranged in the width direction of the optical fiber ribbon, arranged longitudinally, and the number of connecting portions arranged in the connecting section adjacent to the non-connecting region is preferably smaller than the number of connecting portions arranged in the connecting section not adjacent to the non-connecting region. This reduces the influence of the connecting portions when the non-connecting region of the optical fiber ribbon is clamped by the holder, making it easier to narrow the width of the optical fiber ribbon.

[0023] The optical fiber ribbon includes a plurality of optical fibers arranged in a direction perpendicular to the optical fiber ribbon, the optical fiber ribbon being arranged in a direction perpendicular to the optical fiber ribbon, and the optical fiber ribbon is arranged in a direction perpendicular to the optical fiber ribbon.

[0024] The connecting region is configured by disposing a plurality of first connecting sections, each having the connecting portions disposed intermittently in the width direction of the optical fiber ribbon, and a second connecting section disposed adjacent to the non-connecting region, intermittently in the longitudinal direction, and the longitudinal distance between the first connecting section and the second connecting section is preferably longer than the longitudinal distance between the first connecting section and the second connecting section. This allows the second connecting sections held by the holder to be positioned so as to be biased toward the non-connecting region, making it easier to narrow the distance between the optical fibers not restrained by the connecting portions in the second connecting section.

[0025] FIRST EMBODIMENT === Structure of Optical Fiber Ribbon 1 Figures 1A and 1B are explanatory diagrams of an optical fiber ribbon 1 according to a first embodiment. Figure 1A is an explanatory diagram of a connection region 20 and a non-connection region 30. Figure 1B is an explanatory diagram of a connection region 20. Figure 1B shows the arrangement of a plurality of connection portions 11 formed in the connection region 20.

[0026] In the following description, each direction is defined as follows. As shown in the figure, the longitudinal direction of the optical fiber ribbon 1 is simply referred to as the "longitudinal direction." Note that the direction parallel to the optical fibers 2 constituting the optical fiber ribbon 1 when the optical fibers 2 are arranged on a plane so as to be approximately parallel (as shown in the figure) is also referred to as the "longitudinal direction." The optical axis direction of the optical fibers 2 constituting the optical fiber ribbon 1 is also referred to as the "longitudinal direction." The direction in which the optical fibers 2 are arranged in the illustrated state is referred to as the "width direction." The direction perpendicular to the tape surface of the optical fiber ribbon 1 in the illustrated state (the direction perpendicular to the paper surface in the figure) is referred to as the "tape thickness direction."

[0027] The optical fiber ribbon 1 of this embodiment is a so-called intermittently connected (intermittently fixed) optical fiber ribbon. The intermittently connected optical fiber ribbon 1 is an optical fiber ribbon in which a plurality of optical fibers 2 are arranged in parallel and intermittently connected. Adjacent pairs of optical fibers 2 are connected by connection portions 11. The connection portions 11 connecting the adjacent pairs of optical fibers 2 are arranged intermittently in the longitudinal direction. The connection portions 11 of the optical fiber ribbon 1 are also arranged two-dimensionally intermittently in the longitudinal and width directions. The connection portions 11 are formed by applying an ultraviolet-curable resin as an adhesive (tape material) and then hardening it by irradiating it with ultraviolet light. The connection portions 11 can also be made of a thermoplastic resin. The areas other than the connection portions 11 between the adjacent pairs of optical fibers 2 are non-connection portions 13 (separation portions). In the non-connection portions 13, the adjacent pairs of optical fibers 2 are not constrained to each other. The non-connection portions 13 are arranged in the width direction of the connection portions 11. The optical fiber ribbon 1 can be rolled into a cylindrical shape (bundle shape) or folded, and can accommodate a large number of optical fibers 2 at high density.

[0028] The intermittently connected optical fiber ribbon 1 is not limited to the configuration shown in Fig. 1A. For example, the number of fibers (the number of optical fibers 2) in the optical fiber ribbon 1 may be changed. Furthermore, the arrangement of the connecting portions 11 may be changed within the scope of the present application.

[0029] In this embodiment, multiple optical fibers 2 are arranged in parallel at intervals wider than the outer diameter of the optical fibers 2. Here, the outer diameter (fiber diameter D) of the optical fibers 2 is 200 μm, and the widthwise interval (first fiber pitch Pf1) of the optical fibers 2 is 250 μm. In the following description, the outer diameter of the optical fibers 2 may be referred to as the "fiber diameter D." Also, in the following description, the widthwise interval of the optical fibers 2 in the optical fiber ribbon 1 may be referred to as the "first fiber pitch Pf1." Note that the fiber diameter D is not limited to 200 μm, but may be 220 μm or less. Also, the first fiber pitch Pf1 is not limited to 250 μm, but may be 250±30 μm (within a range of 220 μm to 280 μm), as long as a gap is formed between two adjacent optical fibers 2.

[0030] As shown in FIG. 1A , the intermittently connected optical fiber ribbon 1 has connected regions 20 and non-connected regions 30. The connected regions 20 are regions in which a plurality of connection portions 11 are formed so as to connect all of the optical fibers 2 (here, 12 optical fibers 2). The non-connected regions 30 are regions between the connected regions 20 where no connection portions 11 are present. The connected regions 20 and the non-connected regions 30 are alternately formed in the longitudinal direction. In other words, the non-connected regions 30 are formed between the connected regions 20, and the connected regions 20 are formed between the non-connected regions 30. As shown in FIG. 1A , the connected regions 20 are repeatedly arranged in the longitudinal direction at a predetermined interval P1. In the following description, the longitudinal interval between the connected regions 20 may be referred to as the "region pitch P1."

[0031] As shown in FIG. 1B , a plurality of connection sections 21 are provided in the connection region 20. Here, two connection sections 21 are provided in one connection region 20. Five to six connection portions 11 are formed intermittently in the width direction in each connection section 21. In each connection section 21, connection portions 11 and non-connection portions 13 are formed alternately in the width direction. The positions of the connection portions 11 in each connection section 21 are different from each other. In other words, the connection portions 11 in each connection section 21 are arranged alternately in the width direction. As a result, two adjacent optical fibers 2 are connected by at least one connection portion 11 in the connection region 20, and all of the optical fibers 2 are intermittently connected by the connection portions 11 belonging to one connection region 20. Note that when the number of connection sections 21 in one connection region 20 is i, i is not limited to 2 and may be 3 or more (described later). Furthermore, when the number of connecting portions 11 in one connecting section 21 is j, j is not limited to 5 or 6, and may be another number (described later).

[0032] Between the connecting sections 21, there are provided non-connecting sections 23 in which no connecting portion 11 exists in the width direction. As shown in FIG. 1B , the multiple (here, two) connecting sections 21 in the connecting region 20 are arranged at a predetermined interval P2 in the longitudinal direction. In the following description, the longitudinal interval between the connecting sections 21 in the connecting region 20 may be referred to as the "section pitch P2." Because the section pitch P2 is longer than the longitudinal dimension of the connecting portion 11, a non-connecting section 23 is formed between the connecting sections 21. The longitudinal length of the non-connecting region 30 is set to be longer than the section pitch P2.

[0033] FIG. 2A is a cross-sectional view of two optical fibers 2 connected by a connecting portion 11, and is a cross-sectional view of the portion where the connecting portion 11 is formed.

[0034] The optical fiber 2 has a bare optical fiber 4, a coating layer 5, and a colored layer 6. The bare optical fiber 4 is composed of a core and a cladding. The coating layer 5 is a layer that coats the bare optical fiber 4. The coating layer 5 is composed of, for example, a primary coating layer (primary coat) and a secondary coating layer (secondary coat). The colored layer 6 is a layer formed on the surface of the coating layer 5. The colored layer 6 is formed by applying a colorant to the surface of the coating layer 5.

[0035] Two adjacent optical fibers 2 are connected by a taping material (ultraviolet curable resin; connecting agent) that constitutes a connecting portion 11. A taping material layer 15 made of the taping material is formed around the entire circumference of the colored layer 6. In addition, a taping material layer 15 made of the taping material is formed on the surface of the colored layer 6 over the entire longitudinal area of ​​the optical fibers 2. The connecting portion 11 has a recessed shape in the middle portion between the two optical fibers 2.

[0036] FIG. 2B is an explanatory diagram of the connecting portion 11 of a first modified example. As shown in the first modified example, the connecting portion 11 does not have to be recessed in the middle portion between the two optical fibers 2. FIG. 2C is an explanatory diagram of the connecting portion 11 of a second modified example. As shown in the second modified example, the taping material layer 15 made of a taping material does not have to be formed around the entire circumference of the colored layer 6. According to the second modified example, the diameter of the optical fiber 2 can be further reduced. Note that the connecting portion 11 (or the taping material layer 15) does not have to be formed on both the upper and lower sides of the line connecting the centers of two adjacent optical fibers 2, and the connecting portion 11 (or the taping material layer 15) may be formed only on one side, either the upper or lower side, of the line connecting the centers of two adjacent optical fibers 2. Furthermore, the connecting portion 11 (or the taping material layer 15) does not have to be formed evenly above and below the line connecting the centers of two adjacent optical fibers 2.

[0037] FIG. 3 is an explanatory diagram of the relationship between the length of the non-connected region 30 of the optical fiber ribbon 1 and the holder 50. As shown in FIG.

[0038] The holder 50 is a member that holds the optical fiber ribbon 1. The holder 50 has a base portion 51 and a lid portion 52.

[0039] The base portion 51 is a member on which the optical fiber ribbon 1 is placed, and has a placement surface 51A for placing the optical fiber ribbon 1. The placement surface 51A is formed with V-grooves (see FIG. 5B ) for aligning the optical fibers 2 at a predetermined pitch.

[0040] The lid portion 52 is a member that can be opened and closed relative to the base portion 51. When the lid portion 52 is closed, the optical fiber ribbon 1 is sandwiched (held) between the mounting surface 51A of the base portion 51 and the lid portion 52. Therefore, the mounting surface 51A of the base portion 51 and the lid portion 52 form a clamping portion that clamps the optical fiber ribbon 1. Here, the longitudinal length Lh of the clamping portion is determined by the width (longitudinal dimension) of the lid portion 52. However, in cases where a pad that comes into contact with the optical fiber ribbon 1 is provided on the inner surface of the lid portion 52, the longitudinal length Lh of the clamping portion is determined by the width (longitudinal dimension) of the pad, not the width (longitudinal dimension) of the lid portion 52.

[0041] When the lid portion 52 is closed and the optical fiber ribbon 1 is held in the holder 50, the optical fibers 2 extend from both sides of the holder 50 (or the clamping portion). In the following description, the side from which the optical fibers 2 extending from the holder 50 extend that will be processed later (the side from which the coating is removed or cut: the tip side of the optical fibers 2) will be referred to as the "processing side," and the opposite side will be referred to as the "base side."

[0042] In the present embodiment, the length of the non-connected region 30 of the optical fiber ribbon 1 is set to be longer than the width Lh (longitudinal dimension) of the clamping portion. Therefore, in the present embodiment, the clamping portion is configured to be able to clamp the non-connected region 30 of the optical fiber ribbon 1 (the holder 50 is configured to hold the optical fiber ribbon 1 without clamping the region where the connecting portion 11 is formed in the clamping portion). As a result, as will be described later, when the optical fiber ribbon 1 is held in the holder 50, the gaps between the multiple optical fibers 2 inside the holder 50 (clamping portion) can be made narrower than the first fiber pitch Pf1, making it easier to narrow the width of the optical fiber ribbon 1 (see FIG. 5B ).

[0043] Furthermore, in this embodiment, when the clamping portion clamps the non-connecting region 30 of the optical fiber ribbon 1, the non-connecting region 30 of the optical fiber ribbon 1 extends from both sides of the clamping portion (see also FIG. 5A ). Here, when the clamping portion clamps the non-connecting region 30 of the optical fiber ribbon 1, the longitudinal length of the non-connecting region 30 extending from the base end side of the clamping portion (the left side in FIG. 3 (or FIG. 5A )) is defined as L1, and the longitudinal length of the non-connecting region 30 extending from the processing side of the holder 50 (the right side in the figure) is defined as L2. As will be described later, the length L1 is desirably set so that the bending radius of the optical fiber 2 when held by the holder 50 is longer than the allowable bending radius R. Specifically, the length L1 is desirably 9.42 mm or more. Furthermore, the length L2 is desirably a length that allows the pair of blades 61A of the sheath removal device 60 to clamp the non-connecting region 30. Specifically, the length L2 is desirably 2 mm or more. Therefore, it is desirable that the length of the non-connected region 30 of the optical fiber ribbon 1 be longer than the length (Lh + L1 + L2) obtained by adding the width Lh of the clamping portion to the length L1 and the length L2, and specifically, it is desirable that the length be longer than the length (Lh + 11.42 mm) obtained by adding 11.42 mm to the length Lh.

[0044] <Method of Fusion Splicing Optical Fibers 2> Figure 4 is a process flow diagram for batch-fusion splicing an optical fiber ribbon 1, in which optical fibers 2 with a fiber diameter of 200 μm are intermittently connected in parallel at a 250 μm pitch, using a fusion splicing device 40 for 200 μm pitches. The diagram also includes a process flow (S001 to S004) for aligning the optical fibers 2 constituting the optical fiber ribbon 1, in which optical fibers 2 with a fiber diameter of 200 μm are intermittently connected in parallel at a 250 μm pitch, at a 200 μm pitch. In the following description, the widthwise spacing of the optical fibers 2 for batch-fusion splicing using the fusion splicing device 40 may be referred to as the "second fiber pitch Pf2." The second fiber pitch Pf2 need only be narrower than the first fiber pitch Pf1, and is not limited to 200 μm.

[0045] First, the worker prepares the 250 μm pitch optical fiber ribbon 1 to be fusion spliced ​​and the holder 50 for 200 μm pitch (S001). In other words, the worker prepares the optical fiber ribbon 1 with a first fiber pitch Pf1 and the holder 50 for a second fiber pitch Pf2. In this example, the worker prepares the optical fiber ribbon 1 shown in FIG. 1A as the 250 μm pitch optical fiber ribbon 1. The holder 50 for 200 μm pitch is a holder for setting the optical fiber ribbon 1 in the fusion splicing device 40 for 200 μm pitch. In this embodiment, a plurality of V-grooves (described later; see FIG. 5B ) are formed at a 200 μm pitch (second fiber pitch Pf2) on the mounting surface 51A of the base portion 51 of the holder 50.

[0046] Next, the worker places the non-connecting region 30 of the optical fiber ribbon 1 on the placement surface 51A of the holder 50 (S002). In this embodiment, as shown in Fig. 3 , the length of the non-connecting region 30 of the optical fiber ribbon 1 is set to be longer than the width Lh of the lid portion 52, and the worker places the non-connecting region 30 of the optical fiber ribbon 1 on the placement surface 51A of the holder 50 so that the non-connecting region 30 of the optical fiber ribbon 1 faces the lid portion 52.

[0047] When the non-connected region 30 of the optical fiber ribbon 1 is placed on the mounting surface 51A of the holder 50, the end of the optical fiber 2 (the part on the right side in the figure) extends outward (to the right side in the figure) from the holder 50. In this embodiment, when the non-connected region 30 of the optical fiber ribbon 1 is placed on the mounting surface 51A of the holder 50, a part of the non-connected region 30 (the part on the right side in the figure) extends outward (to the right side in the figure) from the holder 50.

[0048] Next, the worker closes the lid portion 52 to cause the holder 50 to hold the optical fiber ribbon 1 (S003). Note that in S002, the optical fiber ribbon 1 is placed on the mounting surface 51A of the holder 50 so that the non-connected region 30 faces the lid portion 52. Therefore, when the lid portion 52 is closed in S003, the non-connected region 30 of the optical fiber ribbon 1 is sandwiched between the mounting surface 51A of the base portion 51 and the lid portion 52. If necessary, the worker may hold the optical fiber ribbon 1 in the holder 50 while narrowing the non-connected region 30 of the optical fiber ribbon 1 in the width direction with his or her fingers (while narrowing the spacing between the multiple optical fibers 2 in the non-connected region 30).

[0049] 5A and 5B are explanatory diagrams showing the state in which the non-connected region 30 is held by the holder 50. Fig. 5B is an enlarged view of the cross section BB of Fig. 5A.

[0050] Because no connecting portions 11 are formed in the non-connecting region 30 of the optical fiber ribbon 1, non-connecting portions 13 (separation portions) are formed between the optical fibers 2, and the optical fibers 2 are not constrained to each other in the non-connecting region 30. Therefore, when the non-connecting region 30 is clamped by the holder 50, the spacing between the multiple optical fibers 2 in the non-connecting region 30 narrows in accordance with the pitch (second fiber pitch Pf2) of the V-grooves on the mounting surface 51A. As a result, by holding the non-connecting region 30 of the optical fiber ribbon 1 in the holder 50, the multiple optical fibers 2 can be aligned at a pitch narrower than the first fiber pitch Pf1 (=250 μm) inside the holder 50 (more specifically, inside the clamping portion of the holder 50), and the width of the optical fiber ribbon 1 can be narrowed.

[0051] 5C is an explanatory diagram of a modified holder 50. A pair of step portions is formed on the mounting surface 51A of the modified holder 50, and the pair of step portions defines the spacing between the optical fibers 2 at both ends in the width direction, thereby aligning the multiple optical fibers 2 at a pitch of 200 μm. As described above, the mounting surface 51A of the holder 50 for a 200 μm pitch is not limited to having V-grooves with a pitch of 200 μm, and other shapes may be used. In other words, it is sufficient that when the non-connected region 30 of the optical fiber ribbon 1 is held in the holder 50, the gaps between the multiple optical fibers 2 inside the holder 50 can be narrowed, thereby narrowing the width of the optical fiber ribbon 1.

[0052] 5A , when the non-connecting region 30 of the optical fiber ribbon 1 is clamped by the holder 50, the optical fibers 2 extend from both sides of the clamping portion. In this embodiment, when the non-connecting region 30 of the optical fiber ribbon 1 is clamped by the holder 50, a portion of the non-connecting region 30 extends outward beyond the clamping portion. Here, the non-connecting region 30 extends a length L1 from the base end side of the clamping portion, and the non-connecting region 30 extends a length L2 from the processing side of the holder 50.

[0053] 5A , at the stage S003, the connecting portions 11 are present between the optical fibers 2 outside the lid portion 52 of the holder 50 (outside the clamping portion), and the spacing between the optical fibers 2 is constrained to 250 μm at the connecting portions 11. Therefore, at the stage S003, the multiple optical fibers 2 outside the lid portion 52 of the holder 50 (outside the clamping portion) are affected by the connecting portions 11 and are therefore arranged at approximately the first fiber pitch Pf1.

[0054] Next, the worker removes the coating from the optical fiber 2 (S004).

[0055] FIG. 6A is an explanatory diagram showing how the coating of the optical fiber 2 is removed by the coating removal device 60.

[0056] The sheath removal device 60 is a device that removes the sheaths of the multiple optical fibers 2 that make up the optical fiber ribbon 1. The sheath removal device 60 is a so-called hot jacket stripper. The sheath removal device 60 has a main body 61 having a pair of blades 61A and a gripping part 62 that grips the holder 50. An operator sets the holder 50 that holds the optical fiber ribbon 1 in the gripping part 62 of the sheath removal device 60, clamps the optical fiber 2 (optical fiber ribbon 1) with the pair of blades 61A of the main body 61 to make an incision in the sheath of the optical fiber 2, and then separates the main body 61 from the gripping part 62, thereby pulling out the sheath of the optical fiber 2 with the pair of blades 61A, thereby removing the sheath of the optical fiber 2. In this embodiment, a portion of the non-connected region 30 (the portion on the right side in the figure) extends outward from the holder 50 (the right side in the figure: the processing side), and the pair of blades 61A clamp the optical fiber 2 (optical fiber tape 1) in the non-connected region 30, removing the coating of the optical fiber 2 on the end side of the clamped portion.

[0057] Incidentally, when the holder 50 is set in the gripping portion 62 of the sheath removal device 60, connecting portions 11 are present between the multiple optical fibers 2 extending from the holder 50 (see FIG. 5A). The connecting portions 11 are located outside the coating layer 5 of the optical fibers 2 (see FIG. 2A). Therefore, when the sheath removal device 60 removes the coating of the optical fibers 2, the connecting portions 11 (taping material layer 15) of the optical fiber ribbon 1 are also removed along with the coating of the optical fibers 2. In other words, when the sheath removal device 60 removes the coating of the optical fibers 2, the multiple optical fibers 2 (bare optical fibers 4) are separated into individual fibers.

[0058] FIG. 6B is an explanatory diagram of the optical fiber ribbon 1 held by the holder 50 after the coating has been removed.

[0059] A plurality of optical fibers 2 (bare optical fibers 4) extend from the processing side (right side in the figure) of the holder 50. On the processing side (right side in the figure), the coupling portions 11 have been removed, so that the optical fibers 2 are no longer constrained by the coupling portions 11. As a result, the influence of the coupling portions 11 is eliminated on the processing side (right side in the figure) of the holder 50, and the spacing between the plurality of optical fibers 2 (bare optical fibers 4) becomes the second fiber pitch Pf2 (=200 μm) in accordance with the pitch of the V-grooves on the mounting surface 51A. In other words, on the processing side (right side in the figure) of the holder 50, the coatings of the optical fibers 2 are removed in S004, so that the optical fibers 2 (bare optical fibers 4) are aligned at the second fiber pitch Pf2 (note that on the base end side (left side in the figure) of the holder 50, the optical fibers 2 are aligned at the first fiber pitch Pf1 due to the influence of the coupling portions 11).

[0060] In this embodiment, the coatings of the multiple optical fibers 2 extending from the processing side (right side in the figure) of the holder 50 are removed to remove the connection portions 11 of the optical fiber ribbon, thereby aligning the multiple optical fibers on the processing side (right side in the figure) of the holder 50 at the second fiber pitch Pf2. However, even if the coatings of the optical fibers 2 are not removed, by removing the connection portions 11 of the optical fiber ribbon 1 extending from the processing side (right side in the figure) of the holder 50, the multiple optical fibers 2 extending from the processing side (right side in the figure) of the holder 50 can be separated into individual fibers, and the multiple optical fibers can be aligned at the second fiber pitch Pf2. On the other hand, by using the coating removal device 60 as in this embodiment, the removal of the connection portions 11 of the optical fiber ribbon 1 and the removal of the coatings of the multiple optical fibers 2 can be performed simultaneously, making the optical fiber alignment work easier.

[0061] In Figure 6B, the length from the end of the processing side of the holder 50 to the edge of the coating where it is stripped is 2 mm. The edge of the coating where it is stripped corresponds to the location where the pair of blades 61A of the coating removal device 60 sandwich the non-connecting region 30 and make an incision in the coating. As shown in Figure 6B, the aforementioned length L2 (see Figure 5A: the longitudinal length of the non-connecting region 30 extending from the processing side of the holder 50) is desirably longer than the length from the end of the processing side of the holder 50 to the edge of the coating where it is stripped (the location where the pair of blades 61A of the coating removal device 60 make an incision in the coating). In other words, the length L2 is desirably 2 mm or more.

[0062] After removing the coating from the optical fiber 2, the worker cuts the end of the optical fiber 2 so that the bare optical fiber 4 has a predetermined length (S005). Typically, the holder 50 holding the optical fiber ribbon 1 is set in a fiber cutter, and the end of the optical fiber 2 is cut using the fiber cutter.

[0063] Next, the worker uses the fusion splicing device 40 to fusion splice the optical fibers 2 together (S006). The worker sets the holder 50 holding the optical fiber ribbon 1 in the fusion splicing device 40, and then uses the fusion splicing device 40 to fusion splice the optical fibers 2 of the optical fiber ribbon 1 together.

[0064] FIG. 7 is an explanatory diagram of the state during fusion splicing.

[0065] The fusion splicing device 40 has an electrode unit 41 and a pair of holder setting units 42. The electrode unit 41 has a pair of electrodes for fusion splicing the optical fibers 2. An arc discharge is generated in the electrode unit 41 to heat the tip ends of the optical fibers 2, causing the tip ends of the optical fibers 2 to melt, thereby fusion splicing the optical fibers 2 together. The holder setting unit 42 is a portion where the holder 50 is set (holder placement unit). The holder setting unit 42 is configured to be movable so that the optical fibers 2 can be aligned together during fusion splicing.

[0066] 7 , the worker holds a plurality of optical fibers 2 in the holders 50, and then sets the holders 50 in the holder setting units 42. When the holders 50 are set in the pair of holder setting units 42, the end faces of the optical fibers 2 (bare optical fibers 4) extending from the processing sides of the holders 50 are arranged opposite each other in the electrode unit 41.

[0067] The fusion splicing device 40 of this embodiment is a 200 μm pitch fusion splicing device 40 and is configured to batch-fuse a plurality of optical fibers 2 aligned at a 200 μm pitch. In this embodiment, the optical fibers 2 (bare optical fibers 4) are aligned at the second fiber pitch Pf2 on the processing side of the holder 50 (the side of the electrode unit 41 when the holder 50 is set in the holder setting unit 42), so that the 250 μm pitch optical fiber ribbon 1 can be batch-fused using the 200 μm pitch fusion splicing device 40.

[0068] 5A , when the holder 50 clamps the non-connected region 30 of the optical fiber ribbon 1, the optical fibers 2 are arranged at a first fiber pitch Pf1 outside the holder 50 (outside the clamping portion), whereas the optical fibers 2 are arranged at a second fiber pitch Pf2 inside the holder 50 (inside the clamping portion). Therefore, when the holder 50 clamps the non-connected region 30 of the optical fiber ribbon 1, the optical fibers 2 are bent near both ends of the holder 50 (clamping portion). In particular, at the base end of the clamping portion, the optical fibers 2 continue to bend for a long period of time, so it is desirable to set the bending radius of the optical fibers 2 equal to or greater than the allowable bending radius. Furthermore, among the optical fibers 2 constituting the optical fiber ribbon 1, the optical fiber 2 located at the end (fiber 1 or fiber N in the case of an N-core optical fiber ribbon 1) has the steepest bending, so it is desirable to set the bending radius of the optical fiber 2 located at the end equal to or greater than the allowable bending radius. Here, the minimum value L0 of the length L1 required to allow an allowable bending radius for the optical fibers will be described.

[0069] 8 is a model diagram of the curvature of fiber N. The curved solid line in the diagram indicates the center of fiber N.

[0070] The optical fiber 2 is curved between the position of the connecting portion 11 closest to the clamping portion of the holder 50 and the end (the end on the base end side) of the clamping portion of the holder 50 (see FIG. 5A ). Point A in FIG. 8 indicates the center position of the Nth fiber at the longitudinal position of the connecting portion 11 closest to the clamping portion of the holder 50. On the base end side of point A (left side in the figure), the multiple optical fibers 2 are arranged in parallel at a first fiber pitch Pf1. Point B in FIG. 8 indicates the center position of the Nth fiber at the end of the clamping portion of the holder 50. On the processing side of point B (right side in the figure), the multiple optical fibers 2 are arranged in parallel at a second fiber pitch Pf2. Between points A and B, the optical fiber 2 is curved in an S-shape. Point C is the center of the S-shape curve. Here, between points A and C, the optical fiber 2 is curved at an allowable bending radius R with the upper side in the figure convex. Point O1 is the bending center of the optical fiber 2 curved between points A and C. Point O1 is located at the longitudinal position of the connecting portion 11 closest to the clamping portion of the holder 50. Between C and B, the optical fiber 2 is bent at the allowable bending radius R, with the downward side in the figure convex. Point O2 is the bending center of the optical fiber 2 bent between C and B. Point O2 is located at the end of the clamping portion of the holder 50. As shown in FIG. 8 , point D is the intersection of an extension of the center line of fiber N when the fibers are arranged in parallel at the second fiber pitch Pf2 with a line connecting point A and point O1. Point E is the intersection of an extension of the center line of fiber N when the fibers are arranged in parallel at the second fiber pitch Pf2 with a line connecting point O2 and point O1. Here, the length between O1 and D is defined as y, and the length between O1 and E is defined as x.

[0071] The bending shown in the figure causes the widthwise position of fiber N to change by a shift amount Ls. The shift amount Ls corresponds to the value obtained by subtracting the widthwise coordinate of point B from the widthwise coordinate of point A. Therefore, Ls is calculated as follows: Ls = (Pf1-Pf2) x (N-1) / 2

[0072] The first fiber pitch Pf1 and the second fiber pitch Pf2 in the above formula are known values. Furthermore, N in the above formula is the number of fibers (the number of optical fibers 2) in the optical fiber ribbon 1, and is therefore also a known value. Therefore, the shift amount Ls can be calculated using the above formula.

[0073] The length y corresponds to the value obtained by subtracting the allowable bending radius R from the shift amount Ls (see FIG. 8). The allowable bending radius R is set to 5 mm, which is a known value. Therefore, the length y can be calculated as y = Ls - R.

[0074] As shown in Figure 8, triangles EBO2 and EDO1 are similar. Therefore, the ratio of length E-O2 to length E-O1 is the same as the ratio of length B-O2 to length D-O1. In other words, the relationship 2R + x:x = R:y holds. Based on this relationship, x can be calculated from R and y.

[0075] The length L0 required to make the bending radius of the optical fiber 2 longer than the allowable bending radius R when the holder 50 holds the optical fiber 2 corresponds to the length D-B in the figure, and can be expressed by the following formula and calculated from R and x.

[0076]

[0077] In this embodiment, Pf1 = 0.25 (mm), Pf2 = 0.20 (mm), N = 12, and R = 5 (mm). In this case, L0 is calculated to be 9.42 (mm). In other words, the length L0 required to make the bending radius of the optical fiber 2 longer than the allowable bending radius R when the holder 50 holds the optical fiber 2 is 9.42 mm.

[0078] 5A , when the clamping portion clamps the non-connected region 30 of the optical fiber ribbon 1, the length in the longitudinal direction of the non-connected region 30 extending from the base end side (left side of FIG. 5A ) of the clamping portion is defined as L1, and in order to set the length L1 so that the bending radius of the optical fiber 2 is longer than the allowable bending radius R when the holder 50 holds the optical fiber 2, it is desirable that the length L1 be equal to or greater than the length L0. For this reason, in the case of this embodiment, it is desirable that L1 be equal to or greater than 9.42 mm.

[0079] <Modification> Fig. 9A is an explanatory diagram of a modification of the optical fiber ribbon 1 of the first embodiment. The optical fiber ribbon 1 of the modification shown in Fig. 9A differs from the optical fiber ribbon 1 shown in Fig. 1A in that it has a mark 8.

[0080] The mark 8 is a mark formed in the non-connected region 30. In other words, the mark 8 is a mark that indicates the position of the non-connected region 30. The mark 8 also serves as a mark for aligning the optical fiber tape 1 with the holder 50. The marks 8 are formed in the same longitudinal position on each of the multiple optical fibers 2, thereby forming a band-like shape across the width of the optical fiber tape 1. The mark 8 may also serve as an identification function for the optical fiber tape 1. For example, the mark 8 on the optical fiber tape 1 in the figure is formed with a pattern that indicates that it is tape No. 2, and has the function of identifying the optical fiber tape 1.

[0081] The marks 8 in this embodiment are formed on all of the optical fibers 2 that make up the optical fiber ribbon 1, so that they are formed across the entire width of the optical fiber ribbon 1. However, it is sufficient that the marks 8 are formed on some of the optical fibers 2 among the plurality of optical fibers 2 that make up the optical fiber ribbon 1. Furthermore, when the marks 8 are formed on only some of the optical fibers 2, it is desirable that the marks 8 be formed on at least the optical fiber 2 (fiber No. 1 or fiber No. N) at the end in the width direction in order to facilitate alignment with the holder 50.

[0082] FIG. 9B is an explanatory diagram of how to use the mark 8.

[0083] In step S002 (see FIG. 4 ) of the above-described method for fusion splicing optical fibers 2 (or method for aligning optical fibers 2), the worker aligns the optical fiber tape 1 and the holder 50 based on the mark 8 so that the mark 8 on the optical fiber tape 1 is located at the center of the mounting surface 51A of the holder 50, as shown in FIG. 9B , and then places the optical fiber tape 1 on the holder 50. This allows the non-connected region 30 of the optical fiber tape 1 to be placed on the mounting surface 51A of the holder 50. Note that even if it is difficult for the worker to visually recognize the position of the connecting portion 11 or the position of the connected region 20 or the non-connected region 30, the mark 8 is easy to see, and therefore, according to the modified example, the task of placing the non-connected region 30 of the optical fiber tape 1 on the mounting surface 51A of the holder 50 (S002 in FIG. 4 ) is facilitated.

[0084] Note that alignment marks (not shown) may be formed on the mounting surface 51A of the holder 50 for alignment with the marks 8 of the optical fiber ribbon 1. This makes it easier to align the optical fiber ribbon 1 and the holder 50 based on the marks 8.

[0085] 9B , when the optical fiber ribbon 1 and the holder 50 are aligned based on the mark 8 and the optical fiber ribbon 1 is held by the holder 50, the non-connected region 30 extends by a predetermined length (the aforementioned length L1) from the base end side of the clamping portion, and also extends by a predetermined length (the aforementioned length L2) from the processing side of the holder 50. In this way, by forming the mark 8 on the optical fiber ribbon 1, it becomes easier to place the optical fiber ribbon 1 on the holder 50 so that the non-connected region 30 of the optical fiber ribbon 1 extends by the desired length from both sides of the clamping portion.

[0086] <Summary> According to the optical fiber aligning method (or fusion splicing method) of the present embodiment, an intermittently connected optical fiber ribbon is prepared, which includes a plurality of optical fibers 2 arranged in parallel at a first fiber pitch Pf1 wider than the fiber diameter D (S001 in FIG. 4 ). The non-connected region 30 of the optical fiber ribbon 1 is held by a holder 50, thereby narrowing the width of the optical fiber ribbon 1 inside the holder 50 (see S003 in FIG. 4 and FIG. 5B ). In this embodiment, the connecting portions 11 of the optical fiber ribbon 1 extending from the holder 50 are removed, thereby allowing the plurality of optical fibers 2 (bare optical fibers 4) separated into individual fibers to be aligned at the second fiber pitch Pf2 (see S004 in FIG. 4 and FIG. 6B ). In this embodiment, when the optical fiber ribbon 1 is held by the holder 50, the optical fibers 2 are not separated into individual fibers at the end (end on the processing side) of the optical fiber ribbon 1, but the plurality of optical fibers 2 are connected together, leaving the connecting portions 11 (see FIGS. 3 and 5A ). Therefore, compared to the task of holding a plurality of optical fibers separated into individual fibers in a holder, in this embodiment, the handling of a plurality of optical fibers 2 is simplified, and the workability of holding a plurality of optical fibers 2 in the holder 50 is improved. As a result, in this embodiment, the alignment task of the optical fibers 2 is simplified. Furthermore, in this embodiment, since the alignment task of the optical fibers 2 is simplified, the fusion splicing task is also simplified.

[0087] The optical fiber ribbon 1 is an intermittently connected optical fiber ribbon including a plurality of optical fibers arranged in parallel at a first fiber pitch Pf1 wider than the fiber diameter D, and a plurality of connection portions 11, the plurality of connection portions 11 being arranged intermittently. The intermittently connected optical fiber ribbon 1 of this embodiment has connection regions 20 in which a plurality of optical fibers (N optical fibers) are intermittently connected by intermittently arranging a plurality of connection portions 11, and non-connection regions 30 in which no connection portions 11 are formed between the connection regions 20. With this intermittently connected optical fiber ribbon 1, the non-connection regions 30 can be held in a holder 50 for the second fiber pitch Pf2 (see S003 in FIG. 4 and FIG. 5B ), and the connection portions 11 of the optical fiber ribbon 1 extending from the holder 50 can be removed, thereby aligning the plurality of optical fibers 2 at the second fiber pitch Pf2 (see S004 in FIG. 4 and FIG. 6B ). Therefore, according to the intermittently connected optical fiber ribbon 1 of this embodiment, the task of aligning multiple optical fibers 2 arranged in parallel at the first fiber pitch Pf1 to the second fiber pitch Pf2 (optical fiber alignment task) is simplified.

[0088] Second Embodiment In the first embodiment, when the number of connection sections 21 in one connection region 20 is i, i was 2. However, i is not limited to 2 and may be another number. Furthermore, when the number of connection portions 11 in one connection section 21 is j, j was 5 to 6 in the first embodiment. However, j is not limited to 5 or 6 and may be another number.

[0089] 10A and 10B are explanatory diagrams of the optical fiber ribbon 1 of the second embodiment. Fig. 10B shows the arrangement of a plurality of connecting portions 11 formed in the connecting region 20 of the optical fiber ribbon 1 of the second embodiment.

[0090] As shown in FIG. 10A , the optical fiber ribbon 1 of the second embodiment is also an intermittently connected optical fiber ribbon 1. The optical fiber ribbon 1 of the second embodiment also includes a connection region 20 and a non-connection region 30. As shown in FIG. 10B , the connection region 20 of the second embodiment also includes a plurality of connection sections 21. In the second embodiment, the number i of connection sections 21 in one connection region 20 is increased compared to the first embodiment, and four connection sections 21 are provided in one connection region 20. Meanwhile, in the second embodiment, the number of connection portions 11 in one connection section 21 is reduced compared to the first embodiment, and the number j of connection portions 11 in one connection section 21 is 2 to 3. In each connection section 21, three non-connection portions 13 are arranged between the connection portions 11. The positions of the connection portions 11 in each connection section 21 are different from each other. In other words, the connection portions 11 in each connection section 21 are arranged alternately in the width direction. As a result, two adjacent optical fibers 2 are connected by at least one connecting portion 11 in the connecting region 20, and all optical fibers 2 are intermittently connected by multiple connecting portions 11 belonging to one connecting region 20.

[0091] In the second embodiment, the number of connecting portions 11 (here, 2) arranged in the connecting section 21 adjacent to the non-connecting region 30 (the connecting section 21 on the rightmost side in FIG. 10B ) is smaller than the number of connecting portions 11 (here, 3) arranged in the connecting section 21 not adjacent to the non-connecting region 30 (for example, the connecting section 21 second from the right in FIG. 10B ). As a result, when the non-connecting region 30 of the optical fiber ribbon 1 of the second embodiment is clamped by the holder 50 as shown in FIG. 5A , the influence of the connecting portions 11 on the outside of the clamping portion is reduced, making it easier to narrow the spacing between the optical fibers 2 and to narrow the width of the optical fiber ribbon 1 inside the holder 50 (more specifically, inside the clamping portion of the holder 50).

[0092] In the second embodiment, the non-connecting portions 13 (three non-connecting portions 13 are arranged here) are located on the outer side in the width direction (upper or lower side in FIG. 10B ) of the connecting portions 11 arranged in the connecting section 21 (the rightmost connecting section 21 in FIG. 10B ) adjacent to the non-connecting region 30. As a result, when the non-connecting region 30 of the optical fiber ribbon 1 of the second embodiment is clamped by the holder 50 as shown in FIG. 5A , the optical fibers 2 located at the ends of the optical fiber ribbon 1 (the optical fibers 2 located on the outer sides in the width direction; fiber No. 1 and fiber No. N) are more likely to be displaced inward, which makes it easier to narrow the spacing between the optical fibers 2 inside the holder 50 (clamping portion) and to narrow the width of the optical fiber ribbon 1.

[0093] Third Embodiment In the above-described embodiment, the clamping portions of the holder 50 clamp the non-connected region 30 of the optical fiber ribbon 1 (the region where the connecting portion 11 is formed is not clamped by the clamping portions, and the holder 50 holds the optical fiber ribbon 1). However, the clamping portions of the holder 50 may clamp a part of the connected region 20 of the optical fiber ribbon 1.

[0094] 11A and 11B are explanatory diagrams of the optical fiber ribbon 1 of the third embodiment. Fig. 11B shows the arrangement of a plurality of connecting portions 11 formed in the connecting region 20 of the optical fiber ribbon 1 of the third embodiment.

[0095] In the third embodiment, one connection region 20 is provided with three connection sections 21 (i.e., i is 3). In the following description, of the three connection sections 21 in the figure, the two left connection sections 21 will be referred to as the first connection section 21A, and the connection section 21 on the right side in the figure will be referred to as the second connection section 21B. The second connection section 21B is a connection section 21 that is disposed adjacent to the non-connection region 30. Furthermore, the second connection section 21B is a connection section 21 that is disposed closer to the clamping portion than the first connection section 21A when the optical fiber ribbon 1 is clamped by the holder 50.

[0096] In the third embodiment, a non-connecting section 23 in which no connecting portion 11 exists in the width direction is also provided between the connecting sections 21. In the following description, the non-connecting section 23 between two first connecting sections 21A may be referred to as the first non-connecting section 23A. Furthermore, the non-connecting section 23 between the first connecting section 21A and the second connecting section 21B may be referred to as the second non-connecting section 23B.

[0097] In the third embodiment, the longitudinal length of the second non-connecting section 23B is longer than the longitudinal length of the first non-connecting section 23A. In other words, the longitudinal distance between the first connecting section 21A and the second connecting section 21B (section pitch P2' in the figure) is longer than the longitudinal distance between the first connecting section 21A and the first connecting section 21A (section pitch P2 in the figure). Therefore, the second connecting section 21B (the rightmost connecting section 21 in FIG. 11B) arranged adjacent to the non-connecting region 30 is arranged so as to be biased toward the non-connecting region 30 from the first connecting section 21A.

[0098] Fig. 12 is an explanatory diagram of the optical fiber ribbon 1 of the third embodiment placed on the holder 50. Fig. 13A is an explanatory diagram of the optical fiber ribbon 1 of the third embodiment held by the holder 50. Fig. 13B is an enlarged view of the B'-B' cross section of Fig. 13A.

[0099] In the third embodiment, the second connecting section 21B, which is disposed adjacent to the non-connecting region 30, is disposed so as to be biased toward the non-connecting region 30 from the first connecting section 21A, and therefore the second connecting section 21B may be included in the region that is clamped by the clamping portions of the holder 50 (here, the mounting surface 51A of the base portion 51 and the lid portion 52). In other words, in the third embodiment, the connecting portion 11 may be included in the region that is clamped by the clamping portions of the holder 50 (here, the mounting surface 51A of the base portion 51 and the lid portion 52).

[0100] In the third embodiment as well, the non-coupling region 30 of the optical fiber ribbon 1 is placed on the mounting surface 51A of the holder 50 so as to face the lid portion 52 (see FIG. 12 ), so when the lid portion 52 of the holder 50 is closed, the non-coupling region 30 of the optical fiber ribbon 1 is sandwiched between the mounting surface 51A of the base portion 51 and the lid portion 52. Since the optical fibers 2 are not constrained to each other in the non-coupling region 30, also in the third embodiment, when the non-coupling region 30 is sandwiched by the holder 50, the spacing between the multiple optical fibers 2 in the non-coupling region 30 narrows in accordance with the pitch (second fiber pitch Pf2) of the V-grooves on the mounting surface 51A.

[0101] In the third embodiment, the connecting portion 11 of the second connecting section 21B is clamped in the clamping portion of the holder 50, and the spacing between the two optical fibers 2 connected by the connecting portion 11 is approximately the first fiber pitch Pf1 (=250 μm) because the optical fibers 2 are constrained by the connecting portion 11. However, because the optical fibers 2 are not constrained in the non-connecting portion 13 included in the second connecting section 21B, the spacing between some of the optical fibers 2 in the second connecting section 21B is narrower than the first fiber pitch Pf1 in accordance with the pitch of the V-groove on the mounting surface 51A (see FIG. 13B ). In particular, in this embodiment, the second connecting section 21B clamped by the holder 50 is positioned so as to be biased toward the non-connecting region 30, and therefore the spacing between the optical fibers 2 not constrained by the connecting portion 11 in the second connecting section 21B is likely to be narrower than the first fiber pitch Pf1. As a result, the width dimension of the optical fiber tape 1 in the second connection section 21B (the width dimension of the optical fiber tape 1 in FIG. 13B) becomes narrower than before being held by the holder 50.

[0102] FIG. 13C is an explanatory diagram of the optical fiber ribbon 1 held by the holder 50 after the coating has been removed.

[0103] In the third embodiment, too, when the connecting portions 11 are removed on the processing side (right side in the figure) of the holder 50, the optical fibers 2 are no longer constrained by the connecting portions 11, and the spacing between the multiple optical fibers 2 (bare optical fibers 4) becomes the second fiber pitch Pf2 (=200 μm) in accordance with the pitch of the V-grooves on the mounting surface 51 A. In other words, on the processing side (right side in the figure) of the holder 50, the coatings of the optical fibers 2 are removed, and the optical fibers 2 (bare optical fibers 4) are aligned at the second fiber pitch Pf2.

[0104] <Number of Connecting Portions 11> FIG. 14 is an explanatory diagram of the allowable number of connecting portions 11 in the second connecting section 21B.

[0105] The upper part of the figure shows a plurality of optical fibers 2 in the second connected section 21B. In the third embodiment, the worker holds the optical fiber ribbon 1 in the holder 50 while narrowing the second connected section 21B of the optical fiber ribbon 1 in the width direction with his or her fingers. For this reason, the optical fiber ribbon 1 in the figure is narrowed in the width direction. In the non-connected section 13, two adjacent optical fibers 2 are in contact with each other. In the connected section 11, the two adjacent optical fibers 2 are restrained by the connected section 11 and are therefore separated by the width C of the connected section 11.

[0106] The lower part of the figure shows a V-groove formed on the mounting surface 51A of the holder 50. In the third embodiment, the worker aligns the optical fiber 2 (here, fiber No. 1) at one end of the optical fiber ribbon 1 with the V-groove, and then aligns the other optical fibers 2 with the V-grooves while narrowing the spacing between the multiple optical fibers 2 in the second connection section 21B. For this reason, the center position of the V-groove on the left side of the figure (the V-groove for fiber No. 1) is shown to coincide with the position of the optical fiber 2 (fiber No. 1) on the left side of the figure.

[0107] If the number n of connecting portions 11 is too large, even if the spacing between the multiple optical fibers 2 in the second connecting section 21B is narrowed, the center position of the optical fiber 2 at the other end (fiber N on the right end in the figure) may be outside the V-groove, making it impossible to place the optical fiber 2 in the V-groove. For this reason, when the spacing between the multiple optical fibers 2 in the second connecting section 21B is narrowed, it is desirable that the center position of the optical fiber 2 (fiber N in this case) at the other end of the optical fiber ribbon 1 be positioned above the V-groove for fiber N.

[0108] Here, Wt is the center-to-center distance between the optical fibers 2 (fiber 1 and fiber N) at both ends when the spacing between the multiple optical fibers 2 in the second connecting section 21B is narrowed. Also, W1 is the width from the center position of the V-groove at one end (here, the V-groove for fiber 1) to the inner crest that constitutes the V-groove at the other end (here, the V-groove for fiber N). Also, W2 is the width from the center position of the V-groove at one end (here, the V-groove for fiber 1) to the outer crest that constitutes the V-groove at the other end (here, the V-groove for fiber N). In this case, it is desirable that Wt, W1, and W2 have the following relationship: W1 < Wt < W2

[0109] In other words, it is desirable that the number n of the connecting portions 11 of the second connecting section 21B be set to an extent that enables the above relationship (W1<Wt<W2) to be established.

[0110] As shown in the upper part of the figure, when the fiber diameter of the optical fiber 2 is D, the number of optical fibers 2 is N, the width of the connecting portion 11 is C, and the number of connecting portions 11 is n, the center-to-center distance Wt between the optical fibers 2 (fiber No. 1 and fiber No. N) at both ends of the optical fiber ribbon 1 is given by the following formula: Wt = D x (N - 1) + C x n

[0111] As shown at the bottom of the figure, the pitch of the V grooves corresponds to the second fiber pitch Pf2 described above. The number of V grooves is N, which is the same as the number of optical fibers 2 that make up the optical fiber ribbon 1. When the width of one V groove is Wv, the width W1 from the center position of the V groove for fiber 1 (or fiber N) to the inner crest that makes up the V groove for fiber N, and the width W2 from the center position of the V groove for fiber N to the outer crest that makes up the V groove for fiber N are respectively expressed by the following equations: W1 = Pf2 × (N-1) - (Wv / 2) W2 = Pf2 × (N-1) + (Wv / 2)

[0112] 15A and 15B are explanatory diagrams of an optical fiber ribbon 1 according to a fourth embodiment. Fig. 16 is an enlarged view of the XX cross section of Fig. 15B.

[0113] In the fourth embodiment, the optical fiber ribbon 1 is also an optical fiber ribbon in which a plurality of optical fibers 2 are arranged in parallel and intermittently connected. In the fourth embodiment, a tape-forming material is applied in a strip shape to the tape surface (a surface parallel to the longitudinal and width directions) of the optical fiber ribbon 1, and the tape-forming material is cured to form a strip-shaped tape-forming material layer 15. By applying and curing the tape-forming material between two optical fibers 2, a connection portion 11 is formed between the two optical fibers 2. In the fourth embodiment, a plurality of connection portions 11 are intermittently arranged in the longitudinal direction between two adjacent optical fibers 2. Furthermore, non-connection portions 13 (separation portions) are formed between the connection portions 11 intermittently formed in the longitudinal direction. In this embodiment, the strip-shaped tape-forming material layer 15 is arranged diagonally with respect to the width direction. As a result, the non-connection portions 13 are arranged in the width direction of the connection portion 11 formed by the tape-forming material layer 15.

[0114] Also in the fourth embodiment, a plurality of optical fibers 2 are arranged in parallel at intervals wider than the outer diameter of the optical fibers 2. Here, the outer diameter (fiber diameter D) of the optical fibers 2 is 200 μm, and the interval (first fiber pitch Pf1) in the width direction of the optical fibers 2 is 250 μm. Therefore, also in the fourth embodiment, a gap is formed between two adjacent optical fibers 2.

[0115] In the fourth embodiment, the intermittently connected optical fiber ribbon 1 also has connected regions 20 and non-connected regions 30, and the connected regions 20 and non-connected regions 30 are formed alternately in the longitudinal direction. In the fourth embodiment, all of the optical fibers 2 (here, 12 optical fibers 2) are connected in the connected regions 20 by a plurality of connecting portions 11. In the fourth embodiment, no connecting portions 11 are formed in the non-connected regions 30. The connected regions 20 are repeatedly arranged at a predetermined interval P1 in the longitudinal direction.

[0116] 15B , a plurality of connection sections 21 are provided in the connection region 20. Here, two connection sections 21 are provided in one connection region 20. Note that when the number of connection sections 21 in one connection region 20 is i, i is not limited to 2, and may be 1, 3 or greater.

[0117] In the fourth embodiment described above, the non-connected region 30 is held in the holder 50 for the second fiber pitch Pf2 (see S003 in FIG. 4 and FIG. 5B), and the coatings of the optical fibers 2 extending from the holder 50 are removed, thereby aligning the optical fibers 2 at the second fiber pitch Pf2 (see S004 in FIG. 4 and FIG. 6B). Therefore, in the intermittently connected optical fiber ribbon 1 of the fourth embodiment, the task of aligning the optical fibers 2 arranged in parallel at the first fiber pitch Pf1 to the second fiber pitch Pf2 (optical fiber alignment task) is also simplified.

[0118] Fifth Embodiment In the above-described embodiment, the method of aligning the optical fibers 2 arranged in parallel at a pitch of 250 μm to a pitch of 200 μm was used in the method of fusion splicing the optical fibers 2. However, the method of aligning the optical fibers 2 in this case may be used for something other than fusion splicing the optical fibers 2.

[0119] 17 is a flow diagram of a manufacturing process for a connectorized optical fiber ribbon 1. The diagram also includes a process flow (S001 to S004) for aligning the optical fibers 2, each having a fiber diameter of 200 μm, at a 200 μm pitch, which constitutes the optical fiber ribbon 1. The optical fibers 2 each having a fiber diameter of 200 μm are intermittently connected in parallel at a 250 μm pitch. In the following description, the spacing between the multiple fiber holes formed in the connector (specifically, the ferrule 70 shown in FIG. 18 ) may be referred to as the "second fiber pitch Pf2." The second fiber pitch Pf2 need only be narrower than the first fiber pitch Pf1, and is not limited to 200 μm.

[0120] Steps S001 to S005 in the figure are the same as steps S001 to S005 in the above-described Figure 4. Here, a description of steps S001 to S005 will be omitted.

[0121] FIG. 18 is an explanatory diagram of the process of S106 in the fifth embodiment.

[0122] In S106, the worker attaches a ferrule 70 to the end of the optical fiber 2. The ferrule 70 in the figure is an optical connector (MT ferrule) specified in JIS C 5981 (F12 type multi-core optical fiber connector). However, the optical connector attached to the end of the optical fiber 2 is not limited to this ferrule 70 (MT ferrule), and other optical connectors (for example, a lens ferrule with a lens formed on the end face) may also be used.

[0123] The ferrule 70 has a plurality of fiber holes (not shown) formed at a second fiber pitch Pf2. As shown in Fig. 18 , with a plurality of optical fibers 2 held in the holder 50, the worker inserts a plurality of optical fibers 2 (bare optical fibers 4) aligned and extending from the processing side of the holder 50 at the second fiber pitch Pf2 into the fiber holes of the ferrule 70. After inserting the ends of the optical fibers 2 into the fiber holes of the ferrule 70, the worker fills the adhesive filling window 71 of the ferrule 70 with adhesive to adhere and fix the optical fibers 2 to the ferrule 70. This attaches the ends of the optical fibers 2 to the ferrule 70.

[0124] In the fifth embodiment, an intermittently connected optical fiber ribbon including a plurality of optical fibers 2 arranged in parallel at a first fiber pitch Pf1 wider than the fiber diameter D is also prepared (S001), and the non-connected region 30 of the optical fiber ribbon 1 is held by a holder 50, thereby narrowing the width of the optical fiber ribbon 1 inside the holder 50 (S003, see FIG. 5B). Therefore, in the fifth embodiment, by removing the connecting portion 11 of the optical fiber ribbon 1 extending from the holder 50, the plurality of optical fibers 2 (bare optical fibers 4) separated into individual fibers can be aligned at the second fiber pitch Pf2 (S004, see FIG. 6B). Also in the fifth embodiment, when the optical fiber ribbon 1 is held by the holder 50, the optical fibers 2 are not separated into individual fibers at the end (end on the processing side) of the optical fiber ribbon 1, but the plurality of optical fibers 2 are connected together, leaving the connecting portion 11 (see FIGS. 3 and 5A). Therefore, compared to the task of holding a plurality of optical fibers that have been separated into individual fibers in a holder, the fifth embodiment also simplifies the handling of a plurality of optical fibers 2, improving the workability of holding a plurality of optical fibers 2 in the holder 50. As a result, the fifth embodiment simplifies the work of aligning the optical fibers 2. Furthermore, the fifth embodiment simplifies the work of aligning the optical fibers, and therefore simplifies the work of manufacturing a connectorized optical fiber ribbon.

[0125] ===Other=== The above embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and it goes without saying that the present invention includes equivalents thereof.

[0126] DESCRIPTION OF SYMBOLS 1 Optical fiber ribbon, 2 Optical fiber, 4 Bare optical fiber, 5 Coating layer, 6 Colored layer, 8 Mark, 11 Connecting portion, 13 Non-connecting portion, 15 Tape material layer, 20 Connecting region, 21 Connecting section, 21A First connecting section, 21B Second connecting section, 23 Non-connecting section, 23A First non-connecting section, 23B Second non-connecting section, 30 Non-connecting region, 40 Fusion splicing device, 41 Electrode portion, 42 Holder setting portion, 50 Holder, 51 Base portion, 51A Mounting surface, 52 Lid portion, 60 Coating removal device, 61 Main body portion, 61A Blade, 62 Grip portion, 70 Ferrule, 71 Adhesive filling window

Claims

An optical fiber arrangement method comprising: preparing an intermittently connected optical fiber ribbon including a plurality of optical fibers arranged side by side at a first pitch larger than a fiber diameter; holding a non-connecting region of the optical fiber ribbon with a holder; reducing a width of the optical fiber ribbon in an interior of the holder; and arranging the plurality of optical fibers, extending out from the holder, with intervals of the plurality of optical fibers reduced from the first pitch to a second pitch smaller than the first pitch by removing connecting portions in a state where the holder is holding the plurality of optical fibers, the connecting portions connecting the plurality of optical fibers extending out from the holder to each other, wherein a region in which a sandwich portion of the holder sandwiches the optical fiber ribbon is the non-connecting region, and a bending radius of the optical fibers extending out from a base end side of the sandwich portion is equal to or larger than an allowable bending radius when the sandwich portion sandwiches the non-connecting region.The optical fiber arrangement method according to claim 1, further comprising: removing the connecting portions by removing coating of the plurality of optical fibers extending out from the holder in the state where the holder is holding the plurality of optical fibers.The optical fiber arrangement method according to claim 1 or 2, further comprising: aligning a position of the optical fiber ribbon in the holder based on a mark formed in the non-connecting region, the holder holding the non-connecting region of the optical fiber ribbon.The optical fiber arrangement method according to claim 1 or 2, wherein a connecting region is formed by intermittently arranging a plurality of connecting sections in a longitudinal direction, the connecting sections being sections in which the connecting portions are intermittently arranged in a width direction of the optical fiber ribbon, and the number of the connecting portions arranged in the connecting section adjacent to the non-connecting region is smaller than the number of the connecting portions arranged in the connecting section not adjacent to the non-connecting region.The optical fiber arrangement method according to claim 1 or 2, wherein a connecting region is formed by intermittently arranging a plurality of connecting sections in a longitudinal direction, the connecting sections being sections in which the connecting portions are intermittently arranged in a width direction of the optical fiber ribbon, and a non-connecting portion is arranged on an outer side, in the width direction, of the connecting portions arranged in the connecting section adjacent to the non-connecting region.The optical fiber arrangement method according to claim 1 or 2, wherein a length of the non-connecting region extending out from a base end side of the sandwich portion is 9.42 mm or more when the sandwich portion sandwiches the non-connecting region.The optical fiber arrangement method according to claim 1 or 2, wherein a length of the non-connecting region is larger than a length obtained by adding 11.42 mm to a length by which the sandwich portion of the holder sandwiches the optical fiber ribbon.An optical fiber arrangement method comprising: preparing an intermittently connected optical fiber ribbon including a plurality of optical fibers arranged side by side at a first pitch larger than a fiber diameter; holding a non-connecting region of the optical fiber ribbon with a holder; reducing a width of the optical fiber ribbon in an interior of the holder; and arranging the plurality of optical fibers, extending out from the holder, with intervals of the plurality of optical fibers reduced from the first pitch to a second pitch smaller than the first pitch by removing connecting portions in a state where the holder is holding the plurality of optical fibers, the connecting portions connecting the plurality of optical fibers extending out from the holder to each other, wherein a connecting region in which the connecting portions are located is partially included in a region in which a sandwich portion of the holder sandwiches the optical fiber ribbon, the connecting region is formed by intermittently arranging a plurality of first connecting sections and a second connecting section in a longitudinal direction, the first connecting sections being sections in which the connecting portions are intermittently arranged in the width direction of the optical fiber ribbon, the second connecting section being arranged adjacent to the non-connecting region, an interval between the first connecting section and the second connecting section in the longitudinal direction is larger than an interval between the first connecting sections in the longitudinal direction, and the second connecting section is included in the region in which the sandwich portion of the holder sandwiches the optical fiber ribbon.The optical fiber arrangement method according to claim 8, wherein            W1 < Wt < W2, where            Wt = D × (N - 1) + C × n            W1 = Pf2 × (N - 1) - (Wv / 2)            W2 = Pf2 × (N - 1) + (Wv / 2),             D is a diameter of the optical fiber,            N is the number of optical fibers forming the optical fiber ribbon and the number of V-grooves in the holder,            C is a width of each of the connecting portions,            n is the number of the connecting portions in the second connecting section,            Pf2 is the second pitch, and            Wv is a width of one of the V-grooves.An optical fiber fusion splicing method comprising: arranging the plurality of optical fibers, extending out from the holder, at the second pitch smaller than the first pitch by the optical fiber arrangement method according to claim 1; then cutting to a predetermined length end portions of the plurality of optical fibers that extend out from the holder and that have been removed of coating, in the state where the holder is holding the plurality of optical fibers; and fusing the plurality of optical fibers arranged at the second pitch by using the fusion splicing device by setting the holder in a fusion splicing device, in the state where the holder is holding the plurality of optical fibers.A method for manufacturing an optical fiber ribbon with a connector, comprising: arranging the plurality of optical fibers, extending out from the holder, at the second pitch smaller than the first pitch by the optical fiber arrangement method according to claim 1; then cutting to a predetermined length end portions of the plurality of optical fibers that extend out from the holder and that have been removed of coating, in the state where the holder is holding the plurality of optical fibers; and attaching the end portions of the plurality of optical fibers to the ferrule by inserting the plurality of optical fibers arranged at the second pitch into fiber holes of a ferrule, in the state where the holder is holding the plurality of optical fibers.An intermittently connected optical fiber ribbon comprising: a plurality of optical fibers arranged side by side at a pitch larger than a fiber diameter; and a plurality of connecting portions that connect adjacent two of the optical fibers to each other, the plurality of connecting portions being intermittently arranged, wherein the intermittently connected optical fiber ribbon has connecting regions in which the plurality of connecting portions are intermittently arranged to intermittently connect the plurality of optical fibers to each other, and a non-connecting region that is located between the connecting regions and in which the connecting portions are not formed, each of the connecting regions is a region in which the connecting portions are formed to connect all of the optical fibers, a plurality of connecting sections in which the connecting portions are intermittently arranged in a width direction of the optical fiber ribbon are located in the connecting regions, a length of the non-connecting region in the longitudinal direction is set to be larger than an interval between the connecting sections in the connecting regions in the longitudinal direction, and the length of the non-connecting region in the longitudinal direction is larger than a length of the connecting region in the longitudinal direction.The intermittently connected optical fiber ribbon according to claim 12, wherein a mark used for alignment of the optical fiber ribbon and a holder configured to hold the optical fiber ribbon is formed in the non-connecting region.The intermittently connected optical fiber ribbon according to claim 12 or 13, wherein the connecting regions are formed by intermittently arranging a plurality of connecting sections in a longitudinal direction, the connecting sections being sections in which the connecting portions are intermittently arranged in a width direction of the optical fiber ribbon, and the number of the connecting portions arranged in the connecting section adjacent to the non-connecting region is smaller than the number of the connecting portions arranged in the connecting section not adjacent to the non-connecting region.The intermittently connected optical fiber ribbon according to claim 12 or 13, wherein the connecting regions are formed by intermittently arranging a plurality of connecting sections in a longitudinal direction, the connecting sections being sections in which the connecting portions are intermittently arranged in a width direction of the optical fiber ribbon, and a non-connecting portion is arranged on an outer side, in the width direction, of the connecting portions arranged in the connecting section adjacent to the non-connecting region.The intermittently connected optical fiber ribbon according to claim 12 or 13, wherein the connecting regions are formed by intermittently arranging a plurality of first connecting sections and a second connecting section in a longitudinal direction, the first connecting sections being sections in which a plurality of the connecting portions are intermittently arranged in the width direction of the optical fiber ribbon, the second connecting section being arranged adjacent to the non-connecting region, and an interval between the first connecting section and the second connecting section in the longitudinal direction is larger than an interval between the first connecting sections in the longitudinal direction.

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