Patent Application
20240393553
The present invention relates to a fiber assembly including a bundle of a plurality of multi-core fibers and a method for manufacturing the fiber assembly.
In the field of optical communications, a multi-core fiber including a plurality of cores is widely used. A document disclosing the multi-core fiber is, for example, Patent Literature 1. A fiber assembly (e.g., a fiber ribbon, a bundle unit, a cable, or a transmission path) including a bundle of a plurality of multi-core fibers is also widely used.
The multi-core fiber may have a marker formed therein, the marker being used to identify the cores. A multi-core fiber in which cores are line-symmetrically arranged and a marker is arranged so as not to overlap the symmetry axis has two kinds of ends (hereinafter, referred to as a “first end” and a “second end”) which are distinguishable from each other by a position of the marker relative to the symmetry axis of the cores. Here, in some cases, multi-core fibers in a fiber assembly are bundled so as to satisfy the following condition.
Condition: First ends of the multi-core fibers are located closer to a first end of the fiber assembly and second ends of the multi-core fibers are located closer to a second end of the fiber assembly.
Given that n multi-core fibers are bundled, the number of patterns of combinations of orientations of the multi-core fibers is 2n. Meanwhile, the number of combinations of orientations of the multi-core fibers satisfying the above condition is only two. That is, conventional fiber assemblies has a quite low degree of freedom in combinations of orientations of the multi-core fibers.
Further, in manufacturing a fiber assembly, each multi-core fiber is typically supplied in a state in which the multi-core fiber is wound around a bobbin or the like. As a method for winding the multi-core fiber, there is one way for winding the multi-core fiber from its first end and another method for winding the multi-core fiber from its second end. In manufacturing a fiber assembly, multi-core fibers should be wound around all bobbins or the like by the same method. Thus, checking and managing the bobbins or the like are difficult. This is a factor that makes it difficult to manufacture the fiber assembly.
Note that such an issue can occur not only in a fiber assembly including a bundle of multi-core fibers each of which has a first end and a second end distinguishable from each other by a position of a marker formed inside a cladding but also in general fiber assemblies including a bundle of multi-core fibers each of which has a first end and a second end distinguishable from each other by an arbitrary means.
One or more embodiments of the present invention provide a fiber assembly that has a relatively high degree of freedom in combinations of orientations of multi-core fibers or that is relatively easy to be manufactured.
A fiber assembly in accordance with one or more embodiments of the present invention is a fiber assembly including: a cladding, a plurality of cores disposed inside the cladding so as to be arranged line-symmetrically when viewed in a cross section of the multi-core fiber, and a marker arranged inside the cladding such that a center of the marker is positioned at a location that does not overlap a symmetry axis of the plurality of cores when viewed in the cross section of the multi-core fiber, each of the plurality of multi-core fibers having a first end and a second end whose arrangement of the plurality of cores and the marker is in a line symmetric relation with that of the first end, the plurality of multi-core fibers being bundled such that there exist (i) a multi-core fiber having a first end located closer to a first end of the fiber assembly and (ii) a multi-core fiber having a second end closer to the first end of the fiber assembly.
A method in accordance with one or more embodiments of the present invention for manufacturing a fiber assembly is a method for manufacturing a fiber assembly that includes a plurality of multi-core fibers each having a cladding, a plurality of cores disposed inside the cladding so as to be arranged line-symmetrically when viewed in a cross section of the multi-core fiber, and a marker arranged inside the cladding such that the marker is positioned at a location that does not overlap a symmetry axis of the plurality of cores when viewed in the cross section of the multi-core fiber, the method including the steps of: arranging the plurality of multi-core fibers each having a first end and a second end whose arrangement of the plurality of cores and the marker is in a line symmetric relation with that of the first end such that there exist (i) a multi-core fiber having a first end located closer to a first end of the fiber assembly and (ii) a multi-core fiber having a second end closer to the first end of the fiber assembly; and bundling the plurality of multi-core fibers.
According to one or more embodiments of the present invention, it is possible to provide a fiber assembly that has a relatively high degree of freedom in combinations of orientations of multi-core fibers or that is relatively easy to be manufactured.
The following description will discuss, with reference to the drawings, a fiber assembly in accordance with one or more embodiments of the present invention. Note that the fiber assembly is a bundle of a plurality of multi-core fibers. The following description will first discuss a multi-core fiber, which is a constituent element of the fiber assembly, and then will discuss a fiber ribbon, a bundle unit, a cable, and a transmission path, each of which is a specific example of the fiber assembly.
The following will describe a multi-core fiber MF with reference to
The multi-core fiber MF includes n (n is a natural number of not less than 2) cores a1 to an and a cladding b. The cladding b is a cylindrical member. The cladding b is made of silica glass, for example. Each core ai (i is a natural number of not less than 1 and not more than n) is a cylindrical-shape area that is provided inside the cladding b, that has a higher refractive index than that of the cladding b, and that extends in a direction in which the cladding b extends. Each core ai is made of, for example, silica glass doped with an updopant such as germanium. The cladding b only needs to have a columnar shape, and may have any cross-sectional shape. For example, the cross-sectional shape of the cladding b may be a polygonal shape such as a quadrangular shape or a hexagonal shape, or may be a barrel shape.
In each of the ends σ1 and σ2, cores a1 to an are arranged line-symmetrically or so as to be in a line symmetric-like form with respect to an axis L1 orthogonal to a central axis L0 of the multi-core fiber MF. Here, the expression that the cores a1 to an are “arranged line-symmetrically” with respect to the axis L1 means that centers of the cores a1 to an are arranged line-symmetrically with respect to the axis L1. Further, the expression that the cores a1 to an are “arranged so as to be in a line symmetric-like form” with respect to the axis L1 means that, with regard to n points x1, x2, . . . , xn arranged line-symmetrically with respect to the axis L1, the core a1 includes the point x1, the core a2 includes the point x2, . . . , and the core an includes the point xn. In the ends σ1 and σ2, the cores a1 to an are arranged so as to avoid the axis L1. In other words, in the ends σ1 and σ2, the cores a1 to an are arranged at locations that do not overlap the axis L1. An aspect in which the cores are “arranged so as to be in a line symmetric-like form” includes, as one specific example, an aspect in which the cores are “arranged line-symmetrically”.
The multi-core fiber MF further includes a marker c. The marker c is an area that is provided inside the cladding b, that has a different refractive index from that of the cladding b, and that extends in a direction in which the cladding b extends. The marker c may have any cross-sectional shape. For example, the cross-sectional shape of the marker c may be a circular shape, a triangular shape, or a quadrangular shape. The marker c is made of, for example, silica glass doped with a downdopant such as fluorine or boron. In this case, the marker c has a refractive index lower than that of the cladding b. Alternatively, the marker c is made of silica glass doped with an updopant such as germanium, aluminum, phosphorus, or chlorine. In this case, the marker c has a refractive index higher than that of the cladding b. The marker c may be formed by, for example, a drilling process or a stack-and-draw process.
In the ends σ1 and σ2, a center of the marker c is positioned so as to avoid the axis L1. In other words, in each of the ends σ1 and σ2, the center (geometric center) of the marker c is positioned at a location that does not overlap the axis L1. Note that the marker c only needs to be positioned so that the center of the marker c does not overlap the axis L1, and the marker c may partially overlap the axis L1. In a case where the marker c does not overlap the axis L1, it is easy to visually find the position of the marker c. This makes it possible to easily identify the cores a1 to an on the basis of the position of the marker c. In a case where the marker c partially overlaps the axis L1, it is possible to secure a great distance between the marker c and the cores a1 to an. Thus, it is possible to inhibit a phenomenon that the marker c gives an adverse effect on optical characteristics of the cores a1 to an.
Note that, with regard to an arbitrary multi-core fiber MF, arrangement of the cores a1 to an and the marker c in the one end σ1 viewed from the front and arrangement of the cores a1 to an and the marker c in the other end σ2 viewed from the front are in a line symmetric relation or in a line symmetric-like relation. Here, the “line symmetric relation” refers to the following relation. That is, when the one end σ1 and the other end σ2 are in plane contact with each other, a center of the core a1 in the one end σ1 overlaps a center of the core a1 in the other end σ2, a center of the core a2 in the one end σ1 overlaps a center of the core a2 in the other end σ2, . . . , a center of the core an in the one end σ1 overlaps a center of the core an in the other end σ2, and a center of the marker c in the one end σ1 overlaps a center of the marker c in the other end σ2. The line symmetric relation is an ideal relation achieved only when (i) a positional relation between the cores a1 to an and the marker c and (ii) sizes and shapes of the cores a1 to an and the marker are strictly maintained along an entire length of the multi-core fiber MF, for example. Meanwhile, the “line symmetric-like relation” refers to the following relation. That is, when the one end σ1 and the other end σ2 are in plane contact with each other, the core a1 in the one end σ1 at least partially overlaps the core a1 in the other end σ2, the core a2 in the one end σ1 at least partially overlaps the core a2 in the other end σ2, . . . , the core an in the one end σ1 at least partially overlaps the core an in the other end σ2, and the marker c in the one end σ1 at least partially overlaps the marker c in the other end σ2. The line symmetric-like relation is a realistic relation achieved when (i) a positional relation between the cores a1 to an and the marker c and (ii) sizes and shapes of the cores a1 to an and the marker are not strictly maintained along an entire length of the multi-core fiber MF due to a production error and/or the like, for example. The “line symmetric-like relation” includes, as one specific example, the “line symmetric relation”.
The following description will discuss, with reference to
(a) of
(b) of
(c) of
(d) of
(e) of
(f) of
The following will describe a fiber ribbon T with reference to
The fiber ribbon T is a fiber assembly including a bundle of na multi-core fibers MF1 to MFna. na is a natural number of not less than 2. In one or more embodiments, na=12. Each multi-core fiber MFi (i is a natural number of not less than 1 and not more than na) has a similar configuration to that of the above-described multi-core fiber MF. The multi-core fibers MF1 to MFna are bundled by a plurality of connecting members 11 (i.e., connectors) provided at distances, for example. For example, each of the connecting members 11 is made of a resin material such as an ultraviolet curable resin, and is used to connect two adjacent multi-core fibers MF (e.g., the multi-core fiber MF1 and the multi-core fiber MF2). Note that the multi-core fibers MF1 to MFna may or may not have, in their cross sections, the same arrangement of cores a1 to an and a marker c. The former configuration can provide an effect of making it possible to carry out connection easily, given that a plurality of multi-core fibers constituting a fiber assembly that is to be connected have, in their cross sections, the same arrangement of cores and a marker.
In the fiber ribbon T, na multi-core fibers MF (multi-core fibers MF1 to MFna) are bundled so as to satisfy the following condition α.
Condition α: There exist (i) a multi-core fiber MF having a first end σ1 located closer to a first end τ1 of the fiber ribbon T and a second end σ2 located closer to a second end τ2 of the fiber ribbon T and (ii) a multi-core fiber MF having a second end σ2 located closer to the first end τ1 of the fiber ribbon T and a first end σ1 located closer to the second end τ2 of the fiber ribbon T.
In the fiber ribbon T illustrated in
Given that na multi-core fibers MF are bundled so as to satisfy the above-indicated condition α, the number of patterns of orientations of the na multi-core fibers MF realizing the fiber ribbon T is 2na-2. That is, it is possible to realize the fiber ribbon T having a high degree of freedom in combinations of orientations of the na multi-core fibers MF. Further, it is possible to reduce the effort required in manufacturing the fiber ribbon T, specifically, the effort of checking and managing bobbins and/or the like so that all the na multi-core fibers MF of which the fiber ribbon T is made are wound in the same manner. This makes it easier to manufacture the fiber ribbon T. Further, as described above, since the fiber ribbon T has a high degree of freedom in combinations of orientations of the na multi-core fibers MF, the fiber ribbon T eliminates the need to carry out a detailed inspection on an end of an obtained fiber assembly, thereby making it possible to reduce the burden caused by an inspection.
In other words, it is possible to achieve a configuration in which a plurality of fiber ribbons include at least one fiber ribbon in which orientations of first and second ends are not the same but are different. Consequently, it is possible to achieve an effect of making it possible to carry out manufacturing relatively easily or to increase a degree of freedom in combinations of orientations of multi-core fibers in a single fiber ribbon, as compared to a fiber ribbon in which first and second ends face the same orientations.
In the fiber ribbon T shown in
Note that each of the multi-core fibers MFi constituting the fiber ribbon T may or may not have, on its outer surface, a printed marker indicating that the core arrangement is positive arrangement or reverse arrangement. Here, the expression that the multi-core fiber MFi has positive arrangement means that the first end σ1 of the multi-core fiber MFi is located closer to the first end τ1 of the fiber ribbon T and the second end σ2 of the multi-core fiber MFi is located closer to the second end τ2 of the fiber ribbon T. Meanwhile, the expression that the multi-core fiber MFi has reverse arrangement means that the second end σ2 of the multi-core fiber MFi is located closer to the first end τ1 of the fiber ribbon T and the first end σ1 of the multi-core fiber MFi is located closer to the second end τ2 of the fiber ribbon T.
Note that the condition α may be replaced with a condition that “there exist (i) a multi-core fiber MF having a first end σ1 located closer to a first end τ1 of the fiber ribbon T and (ii) a multi-core fiber MF having a second end σ2 located closer to the first end τ1 of the fiber ribbon T”. That is, on the side closer to the second end τ2 of the fiber ribbon T, the na multi-core fibers MF may not be bundled so as to satisfy the condition α.
Note that, with regard to the connecting members 11a to 11c which are closest to the first end τ1 of the fiber ribbon T or the connecting members 11d to 11f which are closest to the second end τ2 of the fiber ribbon T, the below-indicated condition A may be satisfied. With this, identifying an orientation of an end of one of multi-core fibers connected by a certain one of the connecting members 11a to 11c allows identification of orientations of ends of the other multi-core fibers connected by the certain one of the connecting members 11a to 11c. Similarly, identifying an orientation of an end of one of multi-core fibers connected by a certain one of the connecting members 11d to 11f allows identification of orientations of ends of the other multi-core fibers connected by the certain one of the connecting members 11d to 11f.
Condition A: Ends of a plurality of multi-core fibers connected by the same connecting member face the same orientation. Here, the expression that the ends of the plurality of multi-core fibers face the same orientation means that the ends of the plurality of multi-core fibers which ends are closer to the first end τ1 of the fiber ribbon T are all (1) on the side closer to the first end σ1 or (2) on the side closer to the second end σ2, the ends of the plurality of multi-core fibers being two ends of each of the plurality of multi-core fibers.
In the specific example shown in
In a case where the number of multi-core fibers connected by the same connecting member is two, it is possible to provide the above effect even if the ends of the two multi-core fibers face different orientations. The reason is as follows. That is, when an orientation of an end of one of these multi-core fibers is identified, an orientation of an end of the other multi-core fiber can be identified as a reverse orientation.
Further, with regard to the connecting members 11a to 11c which are closest to the first end τ1 of the fiber ribbon T or the connecting members 11d to 11f which are closest to the second end τ2 of the fiber ribbon T, the below-indicated condition B may be satisfied. With this, identifying an order of arrangement of orientations of ends of multi-core fibers connected by any one of the connecting members 11a to 11c allows identification of an order of arrangement of orientations of ends of multi-core fibers connected by the other connecting members. Similarly, identifying an order of arrangement of orientations of ends of multi-core fibers connected by any one of the connecting members 11d to 11f allows identification of an order of arrangement of orientations of ends of multi-core fibers connected by the other connecting members.
Condition B: Arrangement orders of orientations of ends of a plurality of multi-core fibers connected by different connecting members are the same.
In the specific example shown in
Note that, with regard to the connecting members 11a to 11c which are closest to the first end ti of the fiber ribbon T, both the conditions A and B may be satisfied. In this case, identifying an orientation of an end of one of multi-core fibers connected by one of the connecting members 11a to 11c allows identification of orientations of ends of all the multi-core fibers MF1, MF2, MF5, MF6, MF9, and MF10 connected by the connecting members 11a to 11c. Similarly, with regard to the connecting members 11d to 11f which are closest to the second end τ2 of the fiber ribbon T, both the conditions A and B may be satisfied. In this case, identifying an orientation of an end of one of multi-core fibers connected by one of the connecting members 11d to 11f allows identification of orientations of ends of all the multi-core fibers MF1, MF2, MF5, MF6, MF9, and MF10 connected by the connecting members 11d to 11f.
The multi-core fibers MF1 to MFna included in the fiber ribbon T may be distinguishable from each other by way of distinguishing features that allow for visual differentiation. The reason is that this makes it easy to connect the multi-core fibers MF1 to MFna to their connection destinations properly. Here, a configuration that makes the multi-core fibers MF1 to MFna distinguishable from each other may be arbitrarily selected. For example, the multi-core fibers MF1 to MFn may have claddings of different shapes. This makes it possible to identify the multi-core fibers MF1 to MFn by visual observation. In a case where the multi-core fibers MF1 to MFn are respectively covered with coatings, colors or shapes of the coatings may be changed. Alternatively, different marks, characters, numbers, and/or the like may be formed (e.g., printed) on the coatings. This makes it possible to identify the multi-core fibers MF1 to MFn by visual observation. In a case where the multi-core fibers MF1 to MFn respectively have connectors provided to their ends, colors or shapes (e.g., positions where a key is provided) of the connectors may be changed. Alternatively, different marks, characters, numbers, and/or the like may be formed on the connectors. This makes it possible to identify the multi-core fibers MF1 to MFn by visual observation. In the description below, the structure (the shape of the cladding, the color or shape of the coating, the mark, character, or number formed on the coating, the color or shape of the connector, the mark, character, or number formed on the connector) that makes the multi-core fibers MF1 to MFna included in the fiber ribbon distinguishable from each other will be described as a distinguishing structure.
The following will describe a bundle unit B with reference to
The bundle unit B is a fiber assembly including a bundle of nb fiber ribbons T1 to Tnb. nb is a natural number of not less than 2. In one or more embodiments, na=12 and nb=6. Each fiber ribbon Tj (j is a natural number of not less than 1 and not more than nb) is configured similarly to the above-described fiber ribbon T. Thus, the bundle unit B can be regarded as a fiber assembly including a bundle of na×nb multi-core fibers MF. For example, the fiber ribbons T1 to Tnb are bundled by two bundle members. Each of the bundle members is a member in the form of thread, string, or tape. A bundle member wound around an upper half of the bundle unit B and a bundle member wound around a lower half of the bundle unit B are entangled with each other at inversion positions. Consequently, the nb fiber ribbons T1 to Tnb are bundled so that the bundle unit B is formed in a substantially columnar shape as a whole. Such a bundle unit B is sometimes called “slot-less type”. Alternatively, the fiber ribbons T1 to Tnb are bundled by a slot. The slot is a columnar structure having a side surface provided with a plurality of grooves (for example, see Japanese Patent Application Publication, Tokukai, No. 2022-92835). The fiber ribbons T1 to Tnb are housed in these grooves, respectively. Two or more fiber ribbons may be housed in a single groove. Alternatively, there may be a groove in which no fiber ribbon is housed. Such a bundle unit B is sometimes called “slot type”. In the slot type bundle unit, the fiber ribbons are arranged separately in respective different grooves. This provides an advantage of making it easy to identify the fiber ribbons. Further, the slot type bundle unit has a merit of allowing the fiber ribbons to be maintained at constant positions along a longitudinal direction of the bundle unit (preventing replacement of the fiber ribbon with another). Note that the na×nb multi-core fibers MF may or may not have, in their cross sections, the same arrangement of cores a1 to an and a marker c. The former configuration can provide an effect of making it possible to carry out connection easily, given that a plurality of multi-core fibers constituting a fiber assembly that is to be connected have, in their cross sections, the same arrangement of cores and a marker.
In a case where na multi-core fibers MF in any one of the fiber ribbons T1 to Tnb are bundled so as to satisfy the above-indicated condition α, a way of bundling the fiber ribbons T1 to Tnb may be arbitrarily selected. That is, the fiber ribbons T1 to Tn may be bundled so as to satisfy the below-indicated condition β′ or so as not to satisfy the below-indicated condition β′. In this case, with regard to the fiber ribbon T including na multi-core fibers MF bundled so as to satisfy the condition α, it is possible to achieve an effect of improving a degree of freedom in combinations of orientations of the multi-core fibers MF. Meanwhile, in a case where the na multi-core fibers MF constituting each fiber ribbon Tj are bundled so as not to satisfy the above-indicated condition α, i.e., in a case where the na multi-core fibers MF constituting each fiber ribbon Tj are bundled so as to satisfy the below-indicated condition α′, the fiber ribbons T1 to Tnb are bundled so as to satisfy the below-indicated condition β′.
Condition α′: The first ends σ1 of the multi-core fibers MF are located closer to the first end τ1 of the fiber ribbon Tj and the second ends σ2 of the multi-core fibers MF are located closer to the second end τ2 of the fiber ribbon Tj.
Condition β′: There exist (i) a fiber ribbon T having a first end τ1 located closer to the first end μ1 of the bundle unit B and a second end τ2 located closer to the second end μ2 of the bundle unit B and (ii) a fiber ribbon T having a second end τ2 located closer to the first end μ1 of the bundle unit B and a first end τ1 located closer to the second end μ2 of the bundle unit B.
In the bundle unit B shown in
Given that nb fiber ribbons T are bundled so as to satisfy the above-indicated condition β′, the number of patterns of orientations of the nb fiber ribbons T realizing the bundle unit B is 2nb-2. That is, it is possible to improve the degree of freedom in combinations of orientations of the nb fiber ribbons T realizing the bundle unit B. Further, it is possible to reduce the effort required in manufacturing the bundle unit B, specifically, the effort of checking and managing bobbins and/or the like so that all the nb fiber ribbons T of which the bundle unit B is made are wound in the same manner. This makes it easier to manufacture the bundle unit B. Moreover, when the multi-core fibers MF constituting each fiber ribbon T satisfy the above-indicated condition α′, it is possible to easily assign the nb fiber ribbons T to connection destinations in a case where the fiber ribbons T are to be assigned to respective different connection destinations, in particular, in a case where each of the connection destinations requires the multi-core fiber MF to have an end whose marker arrangement is identical to that of the connection destination.
Note that, in a case where (1) na multi-core fibers MF in any one of the fiber ribbons T1 to Tnb are bundled so as to satisfy the above-indicated condition α and (2) na multi-core fibers MF constituting each fiber ribbon Tj are bundled so as to satisfy the above-indicated condition α′ and the fiber ribbons T1 to Tnb are bundled so as to satisfy the above-indicated condition β′, na×nb multi-core fibers MF constituting the bundle unit B satisfy the below-indicated condition β.
Condition β: There exist (i) a multi-core fiber MF having a first end σ1 located closer to the first end μ1 of the bundle unit B and a second end σ2 located closer to the second end μ2 of the bundle unit B and (ii) a multi-core fiber MF having a second end σ2 located closer to the first end μ1 of the bundle unit B and a first end σ1 located closer to the second end μ2 of the bundle unit B.
Note that the condition α′ may be replaced with a condition that “the first ends σ1 of the multi-core fibers MF are located closer to the first end τ1 of the fiber ribbon Tj”. That is, on the side closer to the second end τ2 of each fiber ribbon Ti, the na multi-core fibers MF may not be bundled so as to satisfy the condition α′.
Further, the condition β′ may be replaced with a condition that “there exist (i) a fiber ribbon T having a first end τ1 located closer to the first end μ1 of the bundle unit B and (ii) a fiber ribbon T having a second end τ2 located closer to the first end μ1 of the bundle unit B”. That is, on the side closer to the second end μ2 of the bundle unit B, the fiber ribbons T1 to Tnb may not be bundled so as to satisfy the condition β′.
Moreover, the condition β may be replaced with a condition that “there exist (i) a multi-core fiber MF having a first end σ1 located closer to the first end μ1 of the bundle unit B and (ii) a multi-core fiber MF having a second end σ2 located closer to the first end μ1 of the bundle unit B”. That is, on the side closer to the second end μ2 of the bundle unit B, the na×nb multi-core fibers MF may not be bundled so as to satisfy the condition β.
Note that, in the slot type bundle unit, a plurality of multi-core fibers housed in each groove may constitute a fiber ribbon (may be bundled) or may not constitute a fiber ribbon (may not be bundled). In the latter case, the multi-core fibers housed in the single groove are bundled by the groove. Further, the multi-core fibers housed in different grooves are separated from each other by a partition wall that partitions the grooves from each other, and thus would not be mixed.
In a case where the multi-core fibers MF1 to MFna in each of the fiber ribbons T1 to Tnb included in the bundle unit B are distinguishable from each other, in at least two of the fiber ribbons, multi-core fibers MFi having identical distinguishing structures may face the same orientation. With this, identifying orientations of the multi-core fibers MF1 to MFna in one of the at least two fiber ribbons enables to easily identify orientations of the multi-core fibers MF1 to MFna in the others of the at least two fiber ribbons by referring to the distinguishing structures.
In a case where the multi-core fibers MF1 to MFna in each of the fiber ribbons T1 to Tnb included in the bundle unit B are distinguishable from each other, in all the fiber ribbons T1 to Tnb, multi-core fibers MFi having identical distinguishing structures may face the same orientation. With this, identifying orientations of the multi-core fibers MF1 to MFna in one of the two fiber ribbons T1 to Tnb enables to easily identify orientations of the multi-core fibers MF1 to MFna in the others of the fiber ribbons T1 to Tnb by referring to the distinguishing structures.
The following will describe a cable C with reference to
The cable C is a fiber assembly including a bundle of nc bundle units B1 to Bnc. nc is a natural number of not less than 2. In one or more embodiments, na=12, nb=6, and nc=4. Each bundle unit Bk (k is a natural number of not less than 1 and not more than nc) has a similar configuration to that of the above-described bundle unit B. Thus, the cable C can be regarded as a fiber assembly including a bundle of na×nb×nc multi-core fibers MF. For example, the bundle units B1 to Bnc are bundled by a cylindrical sheath. The cable C configured in this manner may sometimes be called “slot-less type”. Alternatively, the bundle units B1 to Bnc are bundled by a slot. The slot is a columnar structure having a side surface provided with a plurality of grooves (for example, see Japanese Patent Application Publication, Tokukai, No. 2022-92835). The bundle units B1 to Bnc are housed in the grooves. Two or more bundle units may be housed in a single groove. Alternatively, there may be a groove in which no fiber ribbon is housed. The cable C configured in this manner may sometimes be called “slot type”. In the slot type cable, the bundle units are arranged separately in respective different grooves. This makes it easy to identify the bundle units, advantageously. Further, the slot type cable has a merit of allowing the bundle units to be maintained at constant positions along a longitudinal direction of the cable (preventing replacement of the bundle unit with another). Note that the na×nb×nc multi-core fibers MF may or may not have, in their cross sections, the same arrangement of cores a1 to an and a marker c. The former configuration can provide an effect of making it possible to carry out connection easily, given that a plurality of multi-core fibers constituting a fiber assembly that is to be connected have, in their cross sections, the same arrangement of cores and a marker.
In a case where na×nb multi-core fibers MF in any one of the bundle units B1 to Bn are bundled so as to satisfy the above-indicated condition β, a way of bundling the bundle units B1 to Bnc may be arbitrarily selected. In this case, with regard to the bundle unit B including na×nb multi-core fibers MF bundled so as to satisfy the condition β, it is possible to achieve an effect of improving a degree of freedom in combinations of orientations of the multi-core fibers MF. Meanwhile, in a case where the na×nb multi-core fibers MF constituting the bundle units Bk are bundled so as not to satisfy the above-indicated condition β, i.e., in a case where the na×nb multi-core fibers MF constituting each bundle unit Bk are bundled so as to satisfy the below-indicated condition β″, the bundle units B1 to Bnc are bundled so as to satisfy the below-indicated condition γ′.
Condition β″: The first ends σ1 of the multi-core fibers MF are located closer to the first end 1 of the bundle unit Bk and the second ends a2 of the multi-core fibers MF are located closer to the second end μ2 of the bundle unit Bk.
Condition γ′: There exist (i) a bundle unit B having a first end μ1 located closer to the first end ν1 of the cable C and a second end μ2 located closer to the second end ν2 of the cable C and (ii) a bundle unit B having a second end μ2 located closer to the first end ν1 of the cable C and a first end μ1 located closer to the second end ν2 of the cable C.
In the cable C shown in
Given that nc bundle units are bundled so as to satisfy the above-indicated condition γ′, the number of patterns of orientations of the nc bundle units B realizing the cable C is 2nc-2. That is, it is possible to improve the degree of freedom in combinations of orientations of the nc bundle units B realizing the cable C. Further, it is possible to reduce the effort required in manufacturing the cable C, specifically, the effort of checking and managing bobbins and/or the like so that all the nc bundle units B of which the cable C is made are wound in the same manner. This makes it easier to manufacture the cable C. Moreover, when the multi-core fibers MF constituting each bundle unit B satisfy the above-indicated condition β″, it is possible to easily assign the nc bundle units B to connection destinations in a case where the bundle units B are to be assigned to respective different connection destinations, in particular, in a case where each of the connection destinations requires the multi-core fiber MF to have an end whose marker arrangement is identical to that of the connection destination.
Note that, in a case where (1) na×nb multi-core fibers MF in any one of the bundle units B1 to Bnc are bundled so as to satisfy the above-indicated condition β and (2) na×nb multi-core fibers MF constituting each bundle unit Bk are bundled so as to satisfy the above-indicated condition β″ and the bundle units B1 to Bnc are bundled so as to satisfy the above-indicated condition γ′, na×nb×nc multi-core fibers MF constituting the cable C satisfy the below-indicated condition γ.
Condition γ: There exist (i) a multi-core fiber MF having a first end σ1 located closer to the first end ν1 of the cable C and a second end σ2 located closer to the second end ν2 of the cable C and (ii) a multi-core fiber MF having a second end σ2 located closer to the first end ν1 of the cable C and a first end σ1 located closer to the second end ν2 of the cable C.
Note that the condition β″ may be replaced with a condition that “the first ends σ1 of the multi-core fibers MF are located closer to the first end μ1 of the bundle unit Bk”. That is, on the side closer to the second end μ2 of each bundle unit Bk, the na×nb multi-core fibers MF may not be bundled so as to satisfy the condition β″.
Further, the condition γ′ may be replaced with a condition that “there exist (i) a bundle unit B having a first end μ1 located closer to the first end ν1 of the cable C and (ii) a bundle unit B having a second end μ2 located closer to the first end ν1 of the cable C”. That is, on the side closer to the second end ν2 of the cable C, the bundle units B1 to Bnc may not be bundled so as to satisfy the condition γ′.
Moreover, the condition γ may be replaced with a condition that “there exist (i) a multi-core fiber MF having a first end σ1 located closer to the first end ν1 of the cable C and (ii) a multi-core fiber MF having a second end σ2 located closer to the first end ν1 of the cable C”. That is, on the side closer to the second end ν2 of the cable C, the na×nb×nc multi-core fibers MF may not be bundled so as to satisfy the condition γ.
Note that, in the slot type cable, a plurality of fiber ribbons housed in each groove may constitute a bundle unit (may be bundled) or may not constitute a bundle unit (may not be bundled). In the latter case, the fiber ribbons housed in a single groove are bundled by the groove. Further, the fiber ribbons housed in different grooves are separated from each other by a partition wall that partitions the grooves from each other, and thus would not be mixed.
In a case where the multi-core fibers MF1 to MFna in each of the fiber ribbons T1 to Tnb×nc in the cable C are distinguishable from each other, in at least two of the fiber ribbons, multi-core fibers MFi having identical distinguishing structures may face the same orientation. With this, identifying orientations of the multi-core fibers MF1 to MFna in one of the at least two fiber ribbons enables to easily identify orientations of the multi-core fibers MF1 to MFna in the other(s) of the at least two fiber ribbons by referring to the distinguishing structures. Further, the at least two fiber ribbons may be configured such that the multi-core fibers MF1 to MFna are arranged in the same order. For example, assume that one of the at least two fiber ribbons includes the multi-core fibers MF1 to MFna wherein the multi-core fiber MF1 covered with a blue coating, the multi-core fiber MF2 covered with a yellow coating, and the multi-core fiber MF3 covered with a green coating, . . . are arranged in this order. In this case, the other(s) of the at least two fiber ribbons may also include the multi-core fibers MF1 to MFna arranged in the same order. With this, identifying orientations of the multi-core fibers MF1 to MFna in one of the at least two fiber ribbons enables to easily identify orientations of the multi-core fibers MF1 to MFna in the other(s) of the at least two fiber ribbons on the basis of the order of the arrangement.
Further, in a case where the multi-core fibers MF1 to MFna in each of the fiber ribbons T1 to Tnb×nc in the cable C are distinguishable from each other, in all the fiber ribbons T1 to Tnb×nc, multi-core fibers MFi having identical distinguishing structures may face the same orientation. With this, identifying orientations of the multi-core fibers MF1 to MFna in one of the fiber ribbons T1 to Tnb×nc enables to easily identify orientations of the multi-core fibers MF1 to MFna in the others of the fiber ribbons T1 to Tnb×nc by referring to the distinguishing structures. Further, the fiber ribbons T1 to Tnb×nc may be configured such that the multi-core fibers MF1 to MFna are arranged in the same order. For example, assume that one of the fiber ribbons T1 to Tnb×nc includes the multi-core fibers MF1 to MFna wherein the multi-core fiber MF1 covered with a blue coating, the multi-core fiber MF2 covered with a yellow coating, and the multi-core fiber MF3 covered with a green coating, . . . are arranged in this order. In this case, the others of the fiber ribbons T1 to Tnb×nc may also include the multi-core fibers MF1 to MFna arranged in the same order. With this, if orientations of the multi-core fibers MF1 to MFna in one of the fiber ribbons T1 to Tnb×nc can be identified, it is possible to easily identify orientations of the multi-core fibers MF1 to MFna in the others of the fiber ribbons T1 to Tnb×nc on the basis of the order of the arrangement.
The following will describe a transmission path L with reference to
The transmission path L is a fiber assembly including a bundle of nd cables C1 to Cnd. nd is a natural number of not less than 2. In one or more embodiments, na=12, nb=6, nc=4, and nd=4. Each cable C1 (1 is a natural number of not less than 1 and not more than nd) has a similar configuration to that of the above-described cable C. Thus, the transmission path L can be regarded as a fiber assembly including a bundle of na×nb×nc×nd multi-core fibers MF. Here, the transmission path L can be realized in the following form. That is, the transmission path L can be realized by the cables C1 to Cnd bundled with a cylindrical duct, a binding band, and/or the like, for example. Further, the transmission path L can be realized by the cables C1 to Cnd buried in the ground and existing in a group. Furthermore, the transmission path L can be realized by the cables C1 to Cnd respectively housed in ducts in a certain duct or stored in a cable rack. Note that the na×nb×nc×nd multi-core fibers MF may or may not have, in their cross sections, the same arrangement of cores a1 to an and a marker c. The former configuration can provide an effect of making it possible to carry out connection easily, given that a plurality of multi-core fibers constituting a fiber assembly that is to be connected have, in their cross sections, the same arrangement of cores and a marker.
In a case where na×nb×nc multi-core fibers MF in any one of the cables C1 to Cnd are bundled so as to satisfy the above-indicated condition γ, a way of bundling the cables C1 to Cnd may be arbitrarily selected. In this case, with regard to the cable C including na×nb×nc multi-core fibers MF bundled so as to satisfy the condition γ, it is possible to achieve an effect of improving a degree of freedom in combinations of orientations of the multi-core fibers MF. Meanwhile, in a case where the na×nb×nc multi-core fibers MF constituting each cable C1 are bundled so as not to satisfy the above-indicated condition γ, i.e., in a case where the na×nb×nc multi-core fibers MF constituting each cable C1 are bundled so as to satisfy the below-indicated condition γ″, the cables C1 to Cnd are bundled so as to satisfy the below-indicated condition δ′.
Condition γ″: The first ends σ1 of the multi-core fibers MF are located closer to the first end ν1 of the cable C1 and the second ends a2 of the multi-core fibers MF are located closer to the second end ν2 of the cable C1.
Condition δ′: There exist (i) a cable C having a first end ν1 located closer to the first end ξ1 of the transmission path L and a second end ν2 located closer to the second end ξ2 of the transmission path L and (ii) a cable C having a second end ν2 located closer to the first end ξ1 of the transmission path L and a first end ν1 located closer to the second end ξ2 of the transmission path L.
In the transmission path L shown in
Given that nd cables C are bundled so as to satisfy the above-indicated condition δ′, the number of patterns of orientations of the nd cables C realizing the transmission path L is 2nd-2 That is, it is possible to improve the degree of freedom in combinations of orientations of the nd cables C realizing the transmission path C. Further, it is possible to reduce the effort required in manufacturing the transmission path L, specifically, the effort of checking and managing bobbins and/or the like so that all the nd cables C of which the transmission path L is made are wound in the same manner. This makes it easier to manufacture the transmission path L. Moreover, when the multi-core fibers MF constituting each cable C satisfy the above-indicated condition γ″, it is possible to easily assign the nd cables C to connection destinations in a case where the cables C are to be assigned to respective different connection destinations, in particular, in a case where each of the connection destinations requires the multi-core fiber MF to have an end whose marker arrangement is identical to that of the connection destination.
Note that, in a case where (1) na×nb×nc multi-core fibers MF in any one of the cables C1 to Cnd are bundled so as to satisfy the above-indicated condition γ and (2) na×nb×nc multi-core fibers MF constituting each cable C are bundled so as to satisfy the above-indicated condition γ″ and the cables C1 to Cnd are bundled so as to satisfy the above-indicated condition δ′, na×nb×nc×nd multi-core fibers MF constituting the transmission path L satisfy the below-indicated condition δ.
Condition δ: There exist (i) a multi-core fiber MF having a first end σ1 located closer to the first end ξ1 of the transmission path L and a second end σ2 located closer to the second end ξ2 of the transmission path L and (ii) a multi-core fiber MF having a second end σ2 located closer to the first end ξ1 of the transmission path L and a first end σ1 located closer to the second end ξ2 of the transmission path L.
Note that the condition γ″ may be replaced with a condition that “the first ends σ1 of the multi-core fibers MF are located closer to the first end ν1 of the cable C1”. That is, on the side closer to the second end ν2 of each cable C1, the na×nb×nc multi-core fibers MF may not be bundled so as to satisfy the condition γ″.
Further, the condition δ′ may be replaced with a condition that “there exist (i) a cable C having a first end ν1 located closer to the first end ξ1 of the transmission path L and (ii) a cable C having a second end ν2 located closer to the first end ξ1 of the transmission path L”. That is, on the side closer to the second end ξ2 of the transmission path L, the cables C1 to Cnd may not be bundled so as to satisfy the condition δ′.
Moreover, the condition δ may be replaced with a condition that “there exist (i) a multi-core fiber MF having a first end σ1 located closer to the first end ξ1 of the transmission path L and (ii) a multi-core fiber MF having a second end σ2 located closer to the first end ξ1 of the transmission path L”. That is, on the side closer to the second end ξ2 of the transmission path L, the na×nb×nc×nd multi-core fibers MF may not be bundled so as to satisfy the condition δ.
A fiber assembly in accordance with a first embodiment of the present invention may include: a plurality of multi-core fibers each having a first end which is designated as one end and a second end which is designated as the other end, the first end and the second end being distinguishable from each other by way of distinguishing features that allow for visual differentiation, the plurality of multi-core fibers being bundled such that there exist (i) a multi-core fiber having a first end located closer to a first end of the fiber assembly and (ii) a multi-core fiber having a second end located closer to the first end of the fiber assembly.
A fiber assembly in accordance with a second embodiment of the present invention may have the configuration of the first embodiment and may be configured such that: each of the plurality of multi-core fibers includes a cladding, a plurality of cores disposed inside the cladding so as to be arranged in a line symmetric-like form when viewed in a cross section of the multi-core fiber, and a marker arranged inside the cladding such that a center of the marker is positioned at a location that does not overlap a symmetry axis of the plurality of cores when viewed in the cross section of the multi-core fiber; and the first end and the second end of each of the plurality of multi-core fibers are distinguishable from each other by a position of the marker relative to the symmetry axis.
A fiber assembly in accordance with a third embodiment of the present invention may have the configuration of the first or second embodiment and may be configured such that: at least part of the plurality of multi-core fibers are bundled so as to constitute a single fiber ribbon.
A fiber assembly in accordance with a fourth embodiment of the present invention may have the configuration of the first or second embodiment and may be configured such that: the plurality of multi-core fibers are bundled so as to constitute a plurality of fiber ribbons; and at least part of the plurality of fiber ribbons are bundled so as to constitute a single bundle unit.
A fiber assembly in accordance with a fifth embodiment of the present invention may have the configuration of the fourth embodiment and may be configured such that: multi-core fibers constituting each of the plurality of fiber ribbons are bundled such that first ends of the multi-core fibers are located closer to a first end of said each of the plurality of fiber ribbons; and the plurality of fiber ribbons are bundled such that there exist (i) a fiber ribbon having a first end located closer to a first end of the bundle unit and (ii) a fiber ribbon having a second end located closer to the first end of the bundle unit.
A fiber assembly in accordance with a sixth embodiment of the present invention may have the configuration of the first or second embodiment and may be configured such that: the plurality of fiber ribbons are bundled so as to constitute a plurality of bundle units; and at least part of the plurality of bundle units are bundled so as to constitute a single cable.
A fiber assembly in accordance with a seventh embodiment of the present invention may have the configuration of the sixth embodiment and may be configured such that: multi-core fibers constituting each of the plurality of bundle units are bundled such that first ends of the multi-core fibers are located closer to a first end of said each of the plurality of bundle units; and the plurality of bundle units are bundled such that there exist (i) a bundle unit having a first end located closer to a first end of the cable and (ii) a bundle unit having a second end located closer to the first end of the cable.
A fiber assembly in accordance with an eighth embodiment of the present invention may have the configuration of the first or second embodiment and may be configured such that: the plurality of multi-core fibers are bundled so as to constitute a plurality of fiber ribbons; the plurality of fiber ribbons are bundled so as to constitute a plurality of bundle units; the plurality of bundle units are bundled so as to constitute a plurality of cables; and at least part of the plurality of cables are bundled so as to constitute a single transmission path.
A fiber assembly in accordance with a ninth embodiment of the present invention may include the configuration of the fourth, sixth, or eighth embodiment and may be configured such that: multi-core fibers constituting at least one fiber ribbon are bundled such that there exist (i) a multi-core fiber having a first end located closer to a first end of the at least one fiber ribbon and (ii) a multi-core fiber having a second end located closer to the first end of the at least one fiber ribbon.
A fiber assembly in accordance with a tenth embodiment of the present invention may include the configuration of the sixth or eighth embodiment and may be configured such that: multi-core fibers constituting at least one bundle unit are bundled such that there exist (i) a multi-core fiber having a first end located closer to a first end of the at least one bundle unit and (ii) a multi-core fiber having a second end located closer to the first end of the at least one bundle unit.
A fiber assembly in accordance with an eleventh embodiment of the present invention may have the configuration of any one of the third to tenth embodiments and may be configured such that: each of the plurality of multi-core fibers includes a cladding, a plurality of cores disposed inside the cladding so as to be arranged in a line symmetric-like form when viewed in a cross section of the multi-core fiber, and a marker arranged inside the cladding such that a center of the marker is positioned at a location that does not overlap a symmetry axis of the plurality of cores when viewed in the cross section of the multi-core fiber; the first end and the second end of each of the plurality of multi-core fibers are distinguishable from each other by a position of the marker relative to the symmetry axis; and the plurality of multi-core fibers constituting the single fiber ribbon or each of the plurality of fiber ribbons are bundled such that the markers of the plurality of multi-core fibers are located on a same side relative to an imaginary plane extending through central axes of the plurality of multi-core fibers at least on a first end of the single fiber ribbon or the one of the plurality of fiber ribbons.
A fiber assembly in accordance with a twelfth embodiment of the present invention may have the configuration of any one of the third to eleventh embodiments and may be configured such that: the plurality of multi-core fibers constituting the single fiber ribbon or each of the plurality of fiber ribbons are bundled with use of a plurality of connecting members disposed at distances; and (i) ends of a plurality of multi-core fibers connected by a same one of some of the plurality of connecting members which are closest to the first end of the fiber assembly face a same orientation or (ii) ends of a plurality of multi-core fibers connected by a same one of some of the plurality of connecting members which are closest to the second end of the fiber assembly face a same orientation, or (i) ends of a plurality of multi-core fibers connected by different ones of some of the plurality of connecting members which are closest to the first end of the fiber assembly are arranged in a same order or (ii) ends of a plurality of multi-core fibers connected by different ones of some of the plurality of connecting members which are closest to the second end of the fiber assembly are arranged in a same order.
A fiber assembly in accordance with a thirteenth embodiment of the present invention may have the configuration of any one of the fourth to twelfth embodiments and may be configured such that: each of at least two of the plurality of fiber ribbons has a plurality of multi-core fibers each having a distinguishing structure with which the plurality of multi-core fibers are distinguishable from each other; and with regard to at least one type of distinguishing structure, multi-core fibers included in the at least two fiber ribbons which multi-core fibers have the at least one type of distinguishing structure face the same orientation.
A fiber assembly in accordance with a fourteenth embodiment of the present invention may have the configuration of the thirteenth embodiment and may be configured such that: at least two of the plurality of fiber ribbons are configured such that multi-core fibers included in the at least two fiber ribbons are arranged in a same order.
A method in accordance with a fifteenth embodiment of the present invention for manufacturing a fiber assembly may be a method for manufacturing a fiber assembly that includes a plurality of multi-core fibers each having a first end which is designated as one end and a second end which is designated as the other end, the first end and the second end being distinguishable from each other, the method comprising the steps of: arranging the plurality of multi-core fibers such that there exist (i) a multi-core fiber having a first end located closer to a first end of the fiber assembly and (ii) a multi-core fiber having a second end located closer to the first end of the fiber assembly; and bundling the plurality of multi-core fibers.
A fiber assembly in accordance with a first embodiment of the present invention may be a fiber assembly including a plurality of multi-core fibers each having a cladding, a plurality of cores disposed inside the cladding so as to be arranged line-symmetrically when viewed in a cross section of the multi-core fiber, and a marker arranged inside the cladding such that a center of the marker is positioned at a location that does not overlap a symmetry axis of the plurality of cores when viewed in the cross section of the multi-core fiber, each of the plurality of multi-core fibers having a first end and a second end whose arrangement of the plurality of cores and the marker is in a line symmetric relation with that of the first end, the plurality of multi-core fibers being bundled such that there exist (i) a multi-core fiber having a first end located closer to a first end of the fiber assembly and (ii) a multi-core fiber having a second end closer to the first end of the fiber assembly.
A fiber assembly in accordance with a second embodiment of the present invention may employ, in addition to the configuration of the first embodiment, a configuration in which: at least part of the plurality of multi-core fibers are bundled so as to constitute a single fiber ribbon.
A fiber assembly in accordance with a third embodiment of the present invention may employ, in addition to the configuration of the first embodiment, a configuration in which: the plurality of multi-core fibers are bundled so as to constitute a plurality of fiber ribbons; and at least part of the plurality of fiber ribbons are bundled so as to constitute a single bundle unit.
A fiber assembly in accordance with a fourth embodiment of the present invention may employ, in addition to the configuration of the third embodiment, a configuration in which: the multi-core fibers constituting each of the plurality of fiber ribbons are bundled such that first ends of the multi-core fibers are located closer to a first end of said each of the plurality of fiber ribbons; and the plurality of fiber ribbons are bundled such that there exist (i) a fiber ribbon having a first end located closer to a first end of the bundle unit and (ii) a fiber ribbon having a second end located closer to the first end of the bundle unit.
A fiber assembly in accordance with a fifth embodiment of the present invention may employ, in addition to the configuration of the first embodiment, a configuration in which: the plurality of multi-core fibers are bundled so as to constitute a plurality of fiber ribbons; the plurality of fiber ribbons are bundled so as to constitute a plurality of bundle units; and at least part of the plurality of bundle units are bundled so as to constitute a single the plurality of bundle units are bundled so as to constitute a single cable.
A fiber assembly in accordance with a sixth embodiment of the present invention may employ, in addition to the configuration of the fifth embodiment, a configuration in which: the multi-core fibers constituting each of the plurality of bundle units are bundled such that first ends of the multi-core fibers are located closer to a first end of said each of the plurality of bundle units; and the plurality of bundle units are bundled such that there exist (i) a bundle unit having a first end located closer to a first end of the cable and (ii) a bundle unit having a second end located closer to the first end of the cable.
A fiber assembly in accordance with a seventh embodiment of the present invention may employ, in addition to the configuration of the first embodiment, a configuration in which: the plurality of multi-core fibers are bundled so as to constitute a plurality of fiber ribbons; the plurality of fiber ribbons are bundled so as to constitute a plurality of bundle units; the plurality of bundle units are bundled so as to constitute a plurality of cables; and at least part of the plurality of cables are bundled so as to constitute a single transmission path.
A fiber assembly in accordance with an eighth embodiment of the present invention may employ, in addition to the configuration of the seventh embodiment, a configuration in which: the multi-core fibers constituting each of the plurality of cables are bundled such that first ends of the multi-core fibers are located closer to a first end of said each of the plurality of cables; and the plurality of cables are bundled such that there exist (i) a cable having a first end located closer to a first end of the transmission path and (ii) a cable having a second end located closer to the first end of the transmission path.
A fiber assembly in accordance with a ninth embodiment of the present invention may employ, in addition to the configuration of the third, fifth, or seventh embodiment, a configuration in which: multi-core fibers constituting at least one fiber ribbon are bundled such that there exist (i) a multi-core fiber having a first end located closer to a first end of the at least one fiber ribbon and (ii) a multi-core fiber having a second end located closer to the first end of the at least one fiber ribbon.
A fiber assembly in accordance with a tenth embodiment of the present invention may employ, in addition to the configuration of the configuration of the fifth or seventh embodiment, a configuration in which: multi-core fibers constituting at least one bundle unit are bundled such that there exist (i) a multi-core fiber having a first end located closer to a first end of the at least one bundle unit and (ii) a multi-core fiber having a second end located closer to the first end of the at least one bundle unit.
A fiber assembly in accordance with an eleventh embodiment of the present invention may employ, in addition to the configuration of the seventh embodiment, a configuration in which: multi-core fibers constituting at least one cable are bundled such that there exist (i) a multi-core fiber having a first end located closer to a first end of the transmission path and (ii) a multi-core fiber having a second end located closer to the first end of the transmission path.
A fiber assembly in accordance with a twelfth embodiment of the present invention may employ, in addition to the configuration of any one of the second to eleventh embodiments, a configuration in which: the plurality of multi-core fibers constituting the single fiber ribbon or each of the plurality of fiber ribbons are bundled such that the markers of the plurality of multi-core fibers are located on a same side relative to an imaginary plane extending through central axes of the plurality of multi-core fibers at least on a first end of the single fiber ribbon or the one of the plurality of fiber ribbons.
A fiber assembly in accordance with a thirteenth embodiment of the present invention may employ, in addition to the configuration of any one of the first to twelfth embodiments, a configuration in which: the plurality of multi-core fibers have, in their first ends and second ends, a same arrangement of the cores and marker.
A fiber assembly in accordance with a fourteenth embodiment of the present invention may employ, in addition to the configuration of any one of the first to thirteenth embodiments, a configuration in which: in each of the plurality of multi-core fibers, the marker is arranged so as not to overlap a symmetry axis of the plurality of cores.
A method in accordance with a fifteenth embodiment of the present invention for manufacturing a fiber assembly may be a method for manufacturing a fiber assembly that includes a plurality of multi-core fibers each having a cladding, a plurality of cores disposed inside the cladding so as to be arranged line-symmetrically when viewed in a cross section of the multi-core fiber, and a marker arranged inside the cladding such that the marker is positioned at a location that does not overlap a symmetry axis of the plurality of cores when viewed in the cross section of the multi-core fiber, the method including the steps of: arranging the plurality of multi-core fibers each having a first end and a second end whose arrangement of the plurality of cores and the marker is in a line symmetric relation with that of the first end such that there exist (i) a multi-core fiber having a first end located closer to a first end of the fiber assembly and (ii) a multi-core fiber having a second end closer to the first end of the fiber assembly; and bundling the plurality of multi-core fibers.
The present invention is not limited to any of the above-described embodiments, but can be altered by a skilled person in the art within the scope of the claims. The present invention also encompasses, in its technical scope, any embodiments derived by combining technical means disclosed in differing embodiments. For example, one or both of the ends of the fiber assembly may be provided with a connector or a fan-in/fan-out device. Further, the scope of the present invention also includes a method for manufacturing the above-described fiber assembly, for example, a method for manufacturing a fiber assembly, the method including the steps of: arranging the plurality of multi-core fibers such that there exist (i) a multi-core fiber having a first end located closer to a first end of the fiber assembly and (ii) a multi-core fiber having a second end located closer to the first end of the fiber assembly; and bundling the plurality of multi-core fibers. Moreover, the fiber ribbon does not need to be constituted only by multi-core fibers. Alternatively, the fiber ribbon may be constituted by a multi-core fiber and a single-core fiber. Similarly, the bundle unit does not need to be constituted only by multi-core fibers. Alternatively, the bundle unit may be constituted by a multi-core fiber and a single-core fiber. Similarly, the transmission path does not need to be constituted only by multi-core fibers. Alternatively, the transmission path may be constituted by a multi-core fiber and a single-core fiber.
The foregoing embodiments have dealt with a fiber assembly including a bundle of multi-core fibers each of which has a first end and a second end being distinguishable from each other by way of distinguishing features that allow for visual differentiation, such as by a position of a marker formed inside a cladding. However, the present invention is not limited to this. For example, the scope of the present invention also encompass a fiber assembly including a bundled of multi-core fibers each having a first end and a second end being visually distinguishable from each other by a cross-sectional shape of a cladding. In this case, the cross-sectional shape of the cladding may be formed so as to be asymmetric with respect to a symmetry axis of the cores. In an example, the cladding may be formed to have a cross-sectional shape in the shape of “D”. For another example, the scope of the present invention also encompass a fiber assembly including a bundled of multi-core fibers each having a first end and a second end being visually distinguishable from each other by shapes of connectors. In this case, the shapes of the connectors provided to the ends of each multi-core fiber may be formed so as to be asymmetric with respect to a symmetry axis of the cores. For example, a key provided on a surface of each connector may be positioned at a location which does not overlap a symmetry axis of the cores. For further another example, the scope of the present invention also encompass a fiber assembly including a bundled of multi-core fibers each having a first end and a second end being visually distinguishable from each other by a position of a mark formed (e.g., printed) on a surface of a cladding or a coating covering the surface of the cladding. In this case, the mark may be formed so that its center (a center of the mark) does not overlap a symmetry axis of the cores.
Although the disclosure has been described with respect to only a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present invention. Accordingly, the scope of the invention should be limited only by the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-168288 | Oct 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/030311 | 8/8/2022 | WO |
