Multi-core optical fiber cord with optical components, method for manufacturing a multi-core optical fiber cord with optical components

Abstract

To provide a multi-fiber optical fiber cord with an optical component etc., capable of securely protecting optical fibers by a cladding.SOLUTION: Optical fibers 5 can be exposed from a small-diameter cladding 11 and a large-diameter cladding 13 with the large-diameter cladding 13 arranged at an outer peripheral part of a small-diameter cladding 11. Consequently, the exposed optical fibers 5 can be rotated respectively, and an optical component 3b can be aligned with and connected to other-end sides of the respective optical fibers 5. Then the large-diameter cladding 13 is slid toward the optical component 3b to fix an end part of the large-diameter cladding 13 to the optical component 3b. Both end parts of the plurality of optical fibers 5 are rotated to be aligned with and connected to the optical components 3a, 3b respectively, so that a multi-fiber optical fiber cord 1 can be obtained which has the optical fibers 5 protected by at least the small-diameter cladding 11 and the large-diameter cladding 13.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a multi-core optical fiber cord with an optical component in which optical components are connected to ends of a plurality of optical fibers, and a method for manufacturing the same.

Background Art

[0002] Conventionally, optical fiber cords having an optical fiber incorporated therein have been used. In an optical fiber cord, an optical fiber is inserted into a tubular jacket together with a tensile strength member, and an end portion of the optical fiber cord is used by connecting an optical connector connectable to another optical component, or an optical component such as a light-emitting element or a light-receiving element.

[0003] As such an optical fiber cord, for example, there has been proposed a fiber cord with a connector including: a ferrule attached to an end of an optical fiber; a housing that accommodates the ferrule and the optical fiber cord such that the ferrule is exposed to the outside from a front end thereof and the optical fiber cord extends from a rear end thereof; a protective tube attached to a portion where the optical fiber is exposed; and a boot member attached to a rear end of the housing (for example, Patent Document 1).

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] In recent years, multi-core optical fiber cords have become increasingly common. Such multi-core optical fiber cords house multiple optical fibers, and their ends are connected to components such as multi-core optical connectors or light-emitting / receiving devices. For example, a so-called MT connector (Mechanically Transferable Splicing Connector) is used as a multi-core optical connector, featuring multiple holes through which each optical fiber is inserted and guide pins at both ends. Using such a multi-core optical connector allows for easy connection of multi-core optical fiber cords to other optical components.

[0006] On the other hand, polarization-maintaining fibers are sometimes used instead of ordinary single-mode fibers. Ordinary single-mode fibers have two orthogonal polarization modes, and ideally this polarization state is maintained. However, when lateral pressure or bending is applied to the optical fiber, the phase change causes the polarization to fluctuate, making the polarization state unstable. In contrast, polarization-maintaining fibers can improve their polarization-maintaining performance by, for example, forming stress-applying sections at both ends of the core.

[0007] Furthermore, due to the recent surge in optical communication traffic, multi-core fibers, which have multiple cores formed in a single fiber, have been proposed as an alternative to the single-core optical fibers currently in use. By using multi-core fibers, it becomes possible to reduce the cost of laying optical fibers and expand transmission capacity.

[0008] However, polarization-maintaining fibers and multi-core fibers have directionality in the circumferential direction, and require rotational alignment in addition to XY alignment, as is the case with ordinary single-mode fibers. Therefore, when connecting to a multi-core connector as described above, rotational alignment must be performed for each optical fiber.

[0009] However, as mentioned above, optical fiber cords are used by being inserted into a tubular outer sheath. That is, the exposed optical fibers between the optical components connected at both ends are protected by the outer sheath. Therefore, while inserted into the outer sheath, it is not possible to rotate the individual optical fibers separately. However, after connecting the optical components at both ends, it is not possible to insert the exposed optical fibers between the optical components into the outer sheath.

[0010] In response to this, methods such as making vertical slits in the outer sheath or making the outer sheath spiral-shaped have been considered. However, these methods can lead to the internal optical fibers protruding when routing the optical cord. Therefore, a method is desired that allows for rotational alignment of the optical fiber even when using a completely tubular outer sheath without slits or cuts.

[0011] The present invention has been made in view of these problems, and aims to provide a multi-core optical fiber cord with optical components that can reliably protect the optical fibers with an outer sheath, even when multiple optical fibers requiring rotational alignment, such as polarization-maintaining fibers or multi-core fibers, are incorporated. [Means for solving the problem]

[0012] To achieve the aforementioned objective, the first invention comprises a plurality of optical fibers, optical components connected to the ends of the plurality of optical fibers, and an outer sheath through which the plurality of optical fibers are inserted collectively, wherein each optical fiber is rotationally aligned and connected to the optical component, and the outer sheath has at least a small diameter outer sheath and a large diameter outer sheath through which the small diameter outer sheath can be inserted. Furthermore, the small-diameter outer sheath and the large-diameter outer sheath are each at least 10 cm shorter than the total length of the optical fiber exposed from the optical component, and the combined length of the small-diameter outer sheath and the large-diameter outer sheath is longer than the total length of the optical fiber exposed from the optical component. The large-diameter outer sheath is positioned on the outer circumference of the small-diameter outer sheath, and when the large-diameter outer sheath is placed over the small-diameter outer sheath, the optical fiber is exposed from both the small-diameter outer sheath and the large-diameter outer sheath, and when the large-diameter outer sheath is slid toward the optical component, the end of the large-diameter outer sheath can be fixed to the optical component. This is a multi-core optical fiber cord with optical components, characterized by the following:

[0014] The second invention comprises a plurality of optical fibers, optical components connected to the ends of the plurality of optical fibers, and an outer sheath through which the plurality of optical fibers are inserted collectively, wherein each optical fiber is rotationally centered and connected to the optical component, and the outer sheath has at least a small diameter outer sheath and a large diameter outer sheath through which the small diameter outer sheath can be inserted. The aforementioned small diameter outer covering is It has a divided end and an undivided end, The aforementioned small diameter outer covering undivided partThe length from the end of the divided portion to the base of the two divided portions is 10 cm or more shorter than the total length of the optical fiber exposed from the optical component, and the sum of the length of the undivided portion of the small diameter outer sheath and the length of the large diameter outer sheath is longer than the total length of the optical fiber exposed from the optical component. The multi-core optical fiber cord with optical components is characterized in that the two divided sections extend longitudinally from the end face of the small diameter outer sheath on the end side of the divided section to the base, and are integrally formed with the non-divided section on the base side, and when the large diameter outer sheath slides toward the end side of the divided section, the large diameter outer sheath is arranged on the outer circumference of the small diameter outer sheath so as to cover the entire length of the divided section, and the end of the large diameter outer sheath is fixed to the optical component.

[0015] The optical components are connected to both ends of the plurality of optical fibers, and at least one of the optical components may be an optical connecting member.

[0016] The optical components are connected to both ends of the plurality of optical fibers, and at least one of the optical components may be equipped with a light-emitting element or a light-receiving element.

[0017] A tensile strength body is arranged along the optical fiber, and both ends of the tensile strength body are connected to the optical component, and it is desirable that the length of the tensile strength body exposed from the optical component is shorter than the length of the optical fiber exposed from the optical component.

[0018] The tensile strength material may be aramid fibers, or it may be twisted aramid fibers.

[0019] The optical fiber may be a polarization-maintaining fiber, and the optical fiber may be a multicore fiber.

[0020] According to the first invention, the outer sheath is separated into at least a small diameter outer sheath and a large diameter outer sheath, and by placing the large diameter outer sheath over the small diameter outer sheath and retracting it, the optical fiber can be exposed. Therefore, the optical fiber can be rotated by this part to perform rotational centering. Furthermore, after connecting to the optical components, by returning the retracted outer sheath to its original position and fixing it, the optical components are connected to both ends, and the optical fiber between the optical components can be protected by the outer sheath along its entire length.

[0021] For example, by setting the lengths of the small-diameter jacket and the large-diameter jacket to be 10 cm or more shorter than the total length of the optical fiber exposed from the optical component respectively, the exposed length of the optical fiber sufficient for performing minimal rotational alignment can be secured. Further, by making the total length of the small-diameter jacket and the large-diameter jacket longer than the total length of the optical fiber exposed from the optical component, the optical fiber between the optical components can be protected over the entire length by the jackets.

[0022] Further, at least one end side of the small-diameter jacket is split into two parts, and when performing rotational alignment, the alignment work can also be performed by opening this split part to expose the optical fiber. On the other hand, by making the total length of the undivided part of the small-diameter jacket and the large-diameter jacket longer than the total length of the optical fiber exposed from the optical component, all split parts of the small-diameter jacket can be covered with the large-diameter jacket after connection. Therefore, the optical fiber between the optical components can be protected over the entire length by the jackets.

[0023] Such an optical component may be an optical connection member such as an optical connector connected to another optical component, or may be a light-emitting element or a light-receiving element. In any case, a plurality of optical fibers are respectively rotationally aligned and optically connected to the optical component.

[0024] Further, a tensile strength member is disposed along the optical fiber, and by making the length of the tensile strength member exposed from the optical component slightly shorter than the length of the optical fiber exposed from the optical component, tension can be reliably borne by the tensile strength member, and application of tensile force to the optical fiber can be suppressed.

[0025] In this case, as the tensile strength member, aramid fiber such as Kevlar (registered trademark) can be used, and twisted aramid fiber may also be used.

[0026] No. 3The invention according to the first aspect is a method for manufacturing an optical fiber cord, wherein one end of each of the plurality of optical fibers is connected to a first optical component, and after the plurality of optical fibers are inserted into the small-diameter outer sheath and the large-diameter outer sheath, the method comprises: covering the small-diameter outer sheath with the large-diameter outer sheath, and exposing the other end side of the optical fibers from the outer sheath; rotating each of the exposed optical fibers to align and connect a second optical component to the other end side of the optical fibers; and sliding the small-diameter outer sheath or the large-diameter outer sheath to fix the other end side of the small-diameter outer sheath or the large-diameter outer sheath to the second optical component. The invention is characterized in that this is a method for manufacturing a multi-core optical fiber cord with optical components.

[0027] According to the 3 invention, for example, starting from a state where ends of the optical fibers and the small-diameter outer sheath are fixed to the first optical component, by covering the small-diameter outer sheath with the large-diameter outer sheath and retracting the large-diameter outer sheath, the optical fibers can be exposed from the outer sheath and rotational alignment can be performed. Furthermore, after the alignment connection between the optical fibers and the second optical component is completed, by sliding the large-diameter outer sheath and fixing the other end side of the large-diameter outer sheath to the second optical component, the entire length of the optical fibers can be protected by the outer sheath.

[0028] According to the 4 invention, the invention according to the 2 aspect is a method for manufacturing a multi-core optical fiber cord with optical components, wherein one end of each of the plurality of optical fibers is connected to a first optical component, and the plurality of optical fibers are inserted into the small-diameter outer sheath, and starting from a state where the small-diameter outer sheath is covered with the large-diameter outer sheath, the method comprises: opening the split portion of the small-diameter outer sheath to expose the other end side of the optical fibers from the outer sheath; rotating each of the exposed optical fibers to align and connect a second optical component to the other end side of the optical fibers; and sliding the large-diameter outer sheath to cover the split portion of the small-diameter outer sheath, and fixing an end of the large-diameter outer sheath to the second optical component. The invention is characterized in that this is a method for manufacturing a multi-core optical fiber cord with optical components.

[0029] According to the 4According to this invention, for example, from a state in which the ends of the optical fiber and the small diameter outer sheath are fixed to the first optical component, the large diameter outer sheath is placed over the small diameter outer sheath and retracted, and the divided portion of the small diameter outer sheath is opened to expose the optical fiber from the outer sheath and perform rotational alignment. After the alignment connection between the optical fiber and the second optical component is completed, the large diameter outer sheath is slid to cover the divided portion of the small diameter outer sheath, and the other end of the large diameter outer sheath is fixed to the second optical component, thereby protecting the entire length of the optical fiber with the outer sheath. [Effects of the Invention]

[0030] According to the present invention, it is possible to provide a multi-core optical fiber cord with optical components that can reliably protect the optical fibers with an outer sheath, even when multiple optical fibers requiring rotational alignment, such as polarization-maintaining fibers or multi-core fibers, are incorporated. [Brief explanation of the drawing]

[0031] [Figure 1] A diagram illustrating the manufacturing process of a multi-core optical fiber cord 1 with optical components. [Figure 2] A diagram illustrating the manufacturing process of a multi-core optical fiber cord 1 with optical components. [Figure 3] A diagram illustrating the manufacturing process of a multi-core optical fiber cord 1 with optical components. [Figure 4] A diagram showing an example of optical component 3b. [Figure 5] A diagram showing another embodiment of the multi-core optical fiber cord 1 with optical components. [Figure 6] A diagram illustrating the manufacturing process of a multi-core optical fiber cord 1a with optical components. [Modes for carrying out the invention]

[0032] The following describes a multi-core optical fiber cord 1 with optical components according to an embodiment of the present invention. Figures 1 to 3 show the manufacturing process of the multi-core optical fiber cord 1 with optical components, and the manufacturing method of the multi-core optical fiber cord 1 with optical components will be described below. In the following description, an example is shown where the optical fiber 5 is a polarization-maintaining fiber, but any optical fiber having directionality in the circumferential direction, such as a multi-core fiber, is applicable.

[0033] First, prepare multiple optical fibers 5 and optical components 3a for connecting to the ends of the multiple optical fibers 5. Next, as shown in Figure 1(a), connect the first optical component, the optical component 3a, to one end of the multiple optical fibers 5. The optical component 3a may be, for example, an optical connection member such as a multi-core optical connector used for connecting to other optical fibers, or it may be a light-emitting member or a light-receiving member equipped with a light-emitting element or a light-receiving element. For example, a light source may be connected to each optical fiber 5 as the optical component 3a.

[0034] As mentioned above, the optical fibers 5 have directionality in the circumferential direction. Therefore, each optical fiber 5 needs to be rotationally aligned with respect to the optical component 3a. The connection between each optical fiber 5 and the optical component 3a can be performed by conventional known methods. For example, the connection end of the optical fiber 5 can be magnified, the rotational position in the circumferential direction can be adjusted, and once the orientation of each part on the end face is set to a predetermined orientation, it can be connected and fixed to the optical component 3a one by one or all at once. In this case, since the optical fibers 5 are exposed, the rotational alignment of each individual optical fiber 5 can be easily performed.

[0035] Furthermore, as shown in Figure 1(b), one end of the tensile strength member 9 is connected to the optical component 3a. For example, aramid fibers (e.g., "Kevlar" (registered trademark)) can be used as the tensile strength member 9. Alternatively, twisted aramid fibers may be used. Multiple tensile strength members 9 may also be used. Additionally, a boot 7 is fixed to the end of the optical component 3a as needed. The boot 7 is usually a molded product of silicone rubber or an elastomer such as a thermoplastic elastomer. Furthermore, in the following description, the boot may also be referred to as the optical component.

[0036] Next, as shown in Figure 1(c), the thin outer sheath 11 is placed over the multiple optical fibers 5 and the tensile strength body 9, and one end of the thin outer sheath 11 (the end on the optical component 3a side) is fixed to the optical component 3a (boot 7). Furthermore, as shown in Figure 1(d), the multiple optical fibers 5 and the tensile strength body 9 are inserted through the thick outer sheath 13. Here, the inner diameter of the thick outer sheath 13 is larger than the outer diameter of the thin outer sheath 11, so the thin outer sheath 11 can be inserted through the thick outer sheath 13. For this reason, the thick outer sheath 13 can be moved to the outer circumference of the thin outer sheath 11 and the thick outer sheath 13 can be placed over the thin outer sheath 11 (direction of arrow C in the figure).

[0037] In this embodiment, the small-diameter outer sheath 11 and the large-diameter outer sheath 13 are sometimes collectively referred to simply as the outer sheath. That is, in the state shown in Figure 1(d), the multiple optical fibers 5 and tensile strength members 9 are inserted together into the outer sheath (small-diameter outer sheath 11 and large-diameter outer sheath 13). The outer sheath is made of a soft resin such as PVC or PE, and can be manufactured by extrusion molding. For this reason, it is softer and thinner than the boot 7.

[0038] Figure 2(a) shows the state in which the large diameter outer sheath 13 is moved to the optical component 3a side and positioned on the outer circumference of the small diameter outer sheath 11. With the large diameter outer sheath 13 covering the small diameter outer sheath 11, the other end of the optical fiber 5 (the side opposite to the optical component 3a) can be exposed from both the small diameter outer sheath 11 and the large diameter outer sheath 13.

[0039] The exposed optical fiber 5 is fitted with various components associated with the second optical component, optical component 3b. In the illustrated example, a spring 14, a spring push 16, a crimping ring 18, an outer sheath crimping ring 20, etc., are used. The other end of the optical fiber 5 is connected to the optical component 3b. At this time, the optical fiber 5 is exposed between the outer sheath and the optical component 3b (part F in the figure). Therefore, each exposed optical fiber 5 can be rotated, and the optical component 3b can be centered and connected to the other end of each optical fiber 5.

[0040] Figure 4 shows an example where the optical component 3b is an MT ferrule and an MPO connector is attached. Multiple holes 17 are formed in the optical component 3b. The holes 17 are the parts through which the tip of the optical fiber 5 is inserted. Guide holes 19 are also formed on both sides of the multiple holes 17 on the end face of the optical component 3b. Guide pins 21 are inserted into the guide holes 19. The guide pins 21 are used to position the optical component 3b relative to the connector to be connected.

[0041] The rotational alignment of the optical fibers 5 can be performed, for example, by magnifying the end face of each optical fiber 5 from the end face side of the optical component 3b with a microscope and adjusting the direction of each optical fiber 5. Therefore, as shown in the figure, the rotational alignment can be performed so that the stress application part 25 and the core 23 are aligned in a straight line (line H in the figure) in the parallel direction of the optical fibers 5. In this state, the optical fibers 5 can be aligned and fixed to the optical component 3b by injecting adhesive from the top of the optical component 3b and allowing it to harden. Note that, as long as the orientation of the optical fibers 5 is aligned, the stress application part 25 and the core 23 of each optical fiber 5 can be aligned in a direction perpendicular to this straight line, as shown in the figure.

[0042] Here, it is desirable that the length of the small-diameter outer sheath 11 (A in Figure 1(c)) and the length of the large-diameter outer sheath 13 (B in Figure 1(d)) be at least 10 cm shorter than the total length of the optical fibers exposed from the optical components 3a and 3b (D in Figure 2(a)). In other words, in Figure 2(a), it is desirable that the length of the optical fiber 5 that can be exposed from the outer sheath between the optical components 3a and 3b (E in Figure 2(a)) be at least 10 cm. By doing so, rotational alignment of each optical fiber 5 can be performed using the conventional method.

[0043] Next, as shown in Figures 2(b) and 2(c), the optical component 3b is housed in the housing 10 and secured by the spring push 16. The housing 10 consists of, for example, an inner housing, an outer housing, a spring, etc., and is pre-assembled. The claws of the spring push 16 can be fitted into a latch inside the housing 10 to secure the two. In addition, since the spring 14 is sandwiched between the optical component 3b and the housing 10, when the optical component 3b is pushed from its front end face, the spring 14 is compressed, applying a pressing force to the end face of the optical component 3b.

[0044] Furthermore, as shown in Figure 3(a), the tensile strength member 9 is sandwiched between the rear end of the spring push 16 and the crimping ring 18 and crimped by the crimping ring 18, thereby fixing the tensile strength member 9 to the optical component 3b. In other words, the tensile strength member 9 is positioned along the optical fiber 5. Here, with both ends of the tensile strength member 9 connected to the optical components 3a and 3b respectively, it is desirable that the length of the tensile strength member 9 exposed from the optical components 3a and 3b is slightly shorter than the length of the optical fiber 5 exposed from the optical components 3a and 3b. That is, it is desirable that a slight deflection of the optical fiber 5 is allowed even when tension is applied to the tensile strength member 9. In this way, the tension applied to the optical fiber 5 can be suppressed.

[0045] Next, as shown in Figure 3(b), the large diameter outer sheath 13 is slid towards the optical component 3b, and the end of the large diameter outer sheath 13 is sandwiched between the rear end of the crimping ring 18 and the outer sheath crimping ring 20 to fix the large diameter outer sheath 13 to the optical component 3b. Alternatively, instead of using the outer sheath crimping ring 20, the end of the large diameter outer sheath 13 may be inserted into the crimping ring 18 to fix it. Finally, as shown in Figure 3(c), the boot 15 is slid and fitted onto each component to complete the assembly of the MPO connector.

[0046] In this embodiment, an example is shown where the optical component 3b is an MT ferrule and the optical connector is an MPO connector, but this is not the only example. Furthermore, even if it is an optical connector, it is not limited to optical connectors having the internal structure shown in the figure. Also, as mentioned above, the optical component 3b may be not only an optical connection member but also one that has an optical light-emitting element or the like. Alternatively, one of the optical components 3a and 3b may be an optical connection member and the other may be an optical component with an optical light-emitting element or the like built in, or both optical components 3a and 3b may be optical connectors. In addition, other known methods such as adhesive bonding or crimping can be applied to fix the outer sheath or tensile strength member 9 to the optical component 3b (3a).

[0047] Here, the total length (A+B) of the thin outer sheath 11 and the thick outer sheath 13 is longer than the total length (E) of the optical fiber exposed from the optical components 3a and 3b. Therefore, when the thin outer sheath 11 and the thick outer sheath 13 are fixed to the optical components 3a and 3b respectively, an overlapping outer sheath portion 12 is formed where the thin outer sheath 11 and the thick outer sheath 13 overlap. In other words, the optical fiber 5 is not exposed from the outer sheath.

[0048] As described above, a multi-core optical fiber cord 1 with optical components can be obtained in which multiple optical fibers 5 are connected to optical components 3a and 3b at both ends by rotational alignment, and the optical fibers 5 are protected by at least a small diameter outer sheath 11 and a large diameter outer sheath 13.

[0049] The overlapping portion 12 where the thin outer sheath 11 and the thick outer sheath 13 overlap may be further fixed by adhesive or heat shrink tubing. Fixing the overlapping portion 12 prevents water from entering the interior through the gap in the overlap. On the other hand, the overlapping portion 12 may be left unfixed and remain overlapped. In this case, when the multi-core optical fiber cord 1 with optical components is bent, the parts can slide against each other, suppressing crushing of the outer sheath due to bending. In this case, the overlapping portion 12 must be long enough so that the thin outer sheath 11 and the thick outer sheath 13 do not come apart when the multi-core optical fiber cord 1 with optical components is bent.

[0050] Furthermore, in this embodiment, the small diameter outer sheath 11 is fixed to the optical component 3a first, and the large diameter outer sheath 13 is fixed to the optical component 3b last. However, the large diameter outer sheath 13 may be fixed to the optical component 3a first, and the small diameter outer sheath 11 may be connected to the optical component 3b. In other words, with the small diameter outer sheath 11 and the large diameter outer sheath 13 inserted through the optical fiber 5, it is sufficient for one of the small diameter outer sheath 11 or the large diameter outer sheath 13 to be fixed to the optical component 3a and the other to the optical component 3b. Also, the fixing of the small diameter outer sheath 11 or the large diameter outer sheath 13 to the optical component 3a may be performed last.

[0051] In the embodiments described above, an example was shown where the small diameter outer sheath 11 and the large diameter outer sheath 13 were approximately the same length, but this is not the only example. For instance, if the total length of the optical fibers exposed from the optical components 3a and 3b (D in Figure 2(a)) is sufficiently longer than the length required for rotational alignment (E in Figure 2(a)), one length may be set to approximately D - 10 cm, and the other length to approximately 10 cm + α. In other words, the lengths of the small diameter outer sheath 11 and the large diameter outer sheath 13 do not have to be the same. However, if the length of the large diameter outer sheath 13 is longer than the length of the small diameter outer sheath 11, the small diameter outer sheath 11 may get trapped inside the large diameter outer sheath 13, making it difficult to remove. Therefore, it is desirable to make the small diameter outer sheath 11 longer.

[0052] Furthermore, the above-described embodiment shows an example in which the outer covering consists of a total of two parts: one small-diameter outer covering 11 and one large-diameter outer covering 13. However, it is not limited to this. For example, as shown in Figure 5(a), it may be composed of a total of three small-diameter outer coverings 11 and one large-diameter outer covering 13. In this case, since both ends of the large-diameter outer covering 13 become an overlapping portion 12, it is necessary to fix the small-diameter outer covering 11 and the large-diameter outer covering 13 in the overlapping portion 12 using adhesive or heat-shrink tubing. Thus, it is also possible to be composed of a total of three or more small-diameter outer coverings 11 and large-diameter outer coverings 13, arranged alternately in the longitudinal direction.

[0053] Furthermore, the above-described embodiment shows an example in which the outer covering consists of a total of two types: one small-diameter outer covering 11 and one large-diameter outer covering 13. However, it is not limited to this. For example, as shown in Figure 5(b), the outer covering may consist of a large-diameter outer covering 13 through which the small-diameter outer covering 11 can be inserted, and a large-diameter outer covering 13a through which the large-diameter outer covering 13 can be further inserted. In this case, the outer covering may consist of a total of three or more types of small-diameter outer coverings 11 and large-diameter outer coverings 13, 13a, etc., and arranged so that those with different outer diameters are lined up sequentially in the longitudinal direction (i.e., outer coverings with diameters that differ by only one step are lined up).

[0054] As described above, according to this embodiment, an optical fiber 5 with optical components 3a and 3b connected to both ends can be protected along its entire length by an outer sheath (small diameter outer sheath 11, large diameter outer sheath 13), and each optical fiber 5 can be rotated and centered before being connected to the optical components 3a and 3b. For this reason, it is applicable even when consisting of multiple polarization-maintaining fibers or multi-core fibers. Furthermore, since no cuts or other features are required in the outer sheath, the protrusion of the optical fiber 5 can be suppressed.

[0055] Next, a second embodiment will be described. Figure 6 shows the manufacturing process of a multi-core optical fiber cord with optical components according to the second embodiment. In the following description, components similar to those in the first embodiment will be denoted by the same reference numerals as in Figures 1 to 5, and redundant explanations will be omitted.

[0056] In the second embodiment, similar to the first embodiment, first, an optical component 3a is connected to one end of a plurality of optical fibers 5 together with a tensile strength body 9. From this state, as shown in Figure 6(a), a small diameter outer sheath 11a is placed over the optical fibers 5 and the tensile strength body 9 (arrow I in the figure). That is, the optical fibers 5 and the tensile strength body 9 are inserted together into the small diameter outer sheath 11a. Note that, unlike the small diameter outer sheath 11, at least one end of the small diameter outer sheath 11a is divided into two parts to form a divided portion 27.

[0057] In this configuration, the thin outer sheath 11a is positioned such that the divided portion 27 faces in the opposite direction to the optical component 3a. The other end of the thin outer sheath 11a (the non-divided portion side) is fixed to the optical component 3a.

[0058] Here, the total length of the small-diameter outer sheath 11a may be considerably longer than the small-diameter outer sheath 11 in the first embodiment. For example, it may be approximately the same length as the total length of the optical fiber 5 exposed from the optical components 3a and 3b in the multi-core optical fiber cord with optical components after connection (corresponding to D in Figure 2(a)).

[0059] Next, as shown in Figure 6(b), the optical fiber 5 and the tensile strength member 9 are inserted into the large-diameter outer sheath 13. That is, the large-diameter outer sheath 13 is placed over the small-diameter outer sheath 11 (arrow J in the figure). At this time, by closing the divided portion 27 of the small-diameter outer sheath 11a, the small-diameter outer sheath 11a can be inserted into the large-diameter outer sheath 13.

[0060] Next, as shown in Figure 6(c), the large diameter outer sheath 13 is moved towards the optical component 3a, and from this state, the divided portion 27 of the small diameter outer sheath 11a is opened. By moving the large diameter outer sheath 13 towards the non-divided portion of the small diameter outer sheath 11a and opening the divided portion 27, a portion of the optical fiber 5 on the side opposite to the optical component 3a can be exposed from the small diameter outer sheath 11 and the large diameter outer sheath 13.

[0061] The exposed optical fiber 5 has the optical component 3b and the components associated with the optical connector arranged on it, and the optical component 3b is connected to the other end of the optical fiber 5 (the side opposite to the optical component 3a). At this time, the optical fiber 5 is exposed at the divided portion 27 of the small diameter outer sheath 11a (part K in the figure), so that each exposed optical fiber 5 can be rotated, and the optical component 3b can be centered and connected to the other end of each optical fiber 5.

[0062] After all the optical fibers 5 are fixed to the optical component 3b, as shown in Figure 6(d), the housing 10 and the like are assembled in the same manner as in the first embodiment, and the large diameter outer sheath 13 is slid towards the optical component 3b (arrow L in the figure) so as to cover the divided portion 27 of the small diameter outer sheath 11a, and the end of the large diameter outer sheath 13 is fixed to the optical component 3b.

[0063] Furthermore, by placing the boot 15 over the connector end, multiple optical fibers 5 are connected to optical components 3a and 3b at both ends, respectively, in a rotationally aligned manner, and a multi-core optical fiber cord 1a with optical components is obtained in which the optical fibers 5 are protected by a thin outer sheath 11a and a thick outer sheath 13.

[0064] Furthermore, it is desirable that the length of the undivided portion of the small diameter outer sheath 11 (the length from the end of the undivided portion of the small diameter outer sheath 11 to the base of the two divided portions 27 (M in Figure 6(d))) be at least 10 cm shorter than the total length of the optical fibers 5 exposed from the optical components 3a and 3b. By doing so, a sufficient exposure length can be secured to allow rotational alignment of each optical fiber 5 between the optical components 3a and 3b.

[0065] Furthermore, by making the total length of the undivided portion of the small-diameter outer sheath 11 and the large-diameter outer sheath 13 longer than the total length of the optical fiber 5 exposed from the optical components 3a and 3b, the large-diameter outer sheath 13 can reliably cover the divided portion 27 of the small-diameter outer sheath 11a. Therefore, when the small-diameter outer sheath 11a and the large-diameter outer sheath 13 are fixed to the optical components 3a and 3b respectively, the optical fiber 5 is not exposed from the outer sheath.

[0066] According to the second embodiment, the same effects as the first embodiment can be obtained. In this way, by exposing the optical fiber 5 for a predetermined length during rotational alignment, and then sliding a part of the outer sheath to cover the entire length of the optical fiber 5, the optical fiber 5 can be protected along its entire length by the outer sheath (small diameter outer sheath 11a, large diameter outer sheath 13), and each optical fiber 5 can be rotated and aligned to connect to the optical components 3a and 3b.

[0067] Although embodiments of the present invention have been described above with reference to the attached drawings, the technical scope of the present invention is not limited to the embodiments described above. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the technical idea described in the claims, and these will naturally also fall within the technical scope of the present invention. [Explanation of Symbols]

[0068] 1, 1a………Multi-core optical fiber cord with optical components 3a, 3b……Optical parts 5… Fiber optic 7, 15... Boots 9……Tensile strength body 10… Housing 11, 11a……Small diameter outer sheath 12… Overlapping parts of the outer covering 13, 13a……Large diameter outer sheath 14... Spring 16... Spring push 17……hole 18... Crimped ring 19… Guide hole 20… Outer crimping ring 21… Guide pin 23... Core 25... Stress application section 27……Divided part

Claims

1. Multiple optical fibers, Optical components connected to the ends of multiple optical fibers, An outer sheath through which multiple optical fibers are inserted collectively, It is equipped with, Each of the aforementioned optical fibers is rotationally aligned and connected to the aforementioned optical component. The aforementioned outer covering comprises at least a small diameter outer covering and a large diameter outer covering through which the small diameter outer covering can be inserted. The small-diameter outer sheath and the large-diameter outer sheath are each at least 10 cm shorter than the total length of the optical fiber exposed from the optical component, and the combined length of the small-diameter outer sheath and the large-diameter outer sheath is longer than the total length of the optical fiber exposed from the optical component. The large diameter outer sheath is positioned on the outer circumference of the small diameter outer sheath, and when the large diameter outer sheath is placed over the small diameter outer sheath, the optical fiber is exposed from both the small diameter outer sheath and the large diameter outer sheath. A multi-core optical fiber cord with an optical component, characterized in that when the large-diameter outer sheath is slid toward the optical component, the end of the large-diameter outer sheath can be fixed to the optical component.

2. Multiple optical fibers, Optical components connected to the ends of multiple optical fibers, An outer sheath through which multiple optical fibers are inserted collectively, It is equipped with, Each of the aforementioned optical fibers is rotationally aligned and connected to the aforementioned optical component. The aforementioned outer covering comprises at least a small diameter outer covering and a large diameter outer covering through which the small diameter outer covering can be inserted. The small diameter sheath has a divided end and an undivided end, and the length from the end of the undivided portion of the small diameter sheath to the base of the divided portion is 10 cm or more shorter than the total length of the optical fiber exposed from the optical component. The total length of the undivided portion of the small diameter outer sheath and the length of the large diameter outer sheath is longer than the total length of the optical fiber exposed from the optical component. The two divided sections extend longitudinally from the end face of the divided section of the small diameter outer shell to the base, and are formed integrally with the non-divided section at the base. A multi-core optical fiber cord with optical components, characterized in that when the large-diameter outer sheath is slid toward the end of the divided portion, the large-diameter outer sheath is positioned on the outer circumference of the small-diameter outer sheath so as to cover the entire length of the divided portion, and the end of the large-diameter outer sheath can be fixed to the optical component.

3. The optical component is connected to both ends of the plurality of optical fibers, The multi-core optical fiber cord with optical components according to claim 1 or 2, characterized in that at least one of the optical components is an optical connecting member.

4. The optical component is connected to both ends of the plurality of optical fibers, A multi-core optical fiber cord with optical components according to claim 1 or 2, characterized in that at least one of the optical components comprises a light-emitting element or a light-receiving element.

5. A tensile strength body is arranged along the optical fiber, and both ends of the tensile strength body are connected to the optical components, The multi-core optical fiber cord with an optical component according to claim 1 or 2, characterized in that the length of the tensile strength body exposed from the optical component is shorter than the length of the optical fiber exposed from the optical component.

6. The multi-core optical fiber cord with optical components according to claim 5, characterized in that the tensile strength material is an aramid fiber or a twisted aramid fiber.

7. The multi-core optical fiber cord with optical components according to claim 1 or 2, characterized in that the optical fiber is a polarization-maintaining fiber.

8. The multi-core optical fiber cord with optical components according to claim 1 or 2, characterized in that the optical fiber is a multi-core fiber.

9. A method for manufacturing a multi-core optical fiber cord with optical components according to claim 1, From a state in which one end of each of the multiple optical fibers is connected to the first optical component, and the multiple optical fibers are inserted into the small diameter outer sheath and the large diameter outer sheath, The steps include: placing the large-diameter outer sheath over the small-diameter outer sheath, thereby exposing the other end of the optical fiber from the outer sheath; The process involves rotating each of the exposed optical fibers and connecting a second optical component to the other end of each optical fiber in a centering manner. A step of sliding the small diameter outer cover or the large diameter outer cover to fix the other end of the small diameter outer cover or the large diameter outer cover to the second optical component, A method for manufacturing a multi-core optical fiber cord with optical components, characterized by comprising the following:

10. A method for manufacturing a multi-core optical fiber cord with optical components according to claim 2, The process involves connecting one end of a plurality of optical fibers to a first optical component, inserting the plurality of optical fibers into the narrow-diameter outer sheath, and then, from a state in which the wide-diameter outer sheath is placed over the narrow-diameter outer sheath, opening the divided portion of the narrow-diameter outer sheath to expose the other end of the optical fiber from the outer sheath, The process involves rotating each of the exposed optical fibers and connecting a second optical component to the other end of each optical fiber in a centering manner. The process of sliding the larger diameter outer cover over the divided portion of the smaller diameter outer cover, and fixing the end of the larger diameter outer cover to the second optical component, A method for manufacturing a multi-core optical fiber cord with optical components, characterized by comprising the following:

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