Magnetic material-containing optical fiber, magnetic material-containing optical fiber tape core, magnetic material-containing multi-fiber optical connector, and method of aligning magnetic material-containing optical fiber

Abstract

According to the present disclosure, precise core position alignment can be performed without end-face observation when inserting and arranging a plurality of MCFs into a multi-fiber optical connector.　The magnetic material-containing optical fiber (FB) according to the present disclosure comprises: a core region (RA); a magnetic region (MR) containing a magnetic material and disposed along the central axis of the core region; and a cladding region (CL) disposed such that the core region and the magnetic region are contained therein. The rotational position of the core region with respect to the central axis of the cladding region is adjusted by a magnetic force acting between the magnetic material contained in the magnetic region and magnetic material contained in a ferrule in a magnetic material-containing multi-fiber optical connector.

Description

Magnetic material-containing optical fiber, magnetic material-containing optical fiber ribbon, magnetic material-containing multi-core optical connector, and method for aligning magnetic material-containing optical fiber

[0001] The present disclosure relates to a magnetic-material-containing optical fiber, a magnetic-material-containing optical fiber ribbon, a magnetic-material-containing multi-fiber optical connector, and a method for aligning a magnetic-material-containing optical fiber.

[0002] Non-Patent Document 1 discloses a technique for connecting an optical fiber cable using a multi-core fiber (MCF) with an optical connector. In order to align one MCF, it is necessary to adjust the horizontal and vertical positions of the cross section of the optical fiber, and further to adjust the rotation angle of the optical fiber around the center of the cross section perpendicular to the longitudinal direction of the optical fiber as the central axis.

[0003] Patent Document 1 discloses a technology in which, when producing a ribbon core wire by bundling multiple MCFs into a tape shape, a magnetic body is applied using a coating layer application device so that the magnetic body is positioned corresponding to the core position of the optical fiber, and the rotation angle of the optical fiber is aligned by the magnetic force of the magnetic body.

[0004] R. Nagase, K. Sakaime, K. Watanabe, and T. Saito, “MU-Type Multicore Fiber Connector”, Trans. IEICE, Vol. E96-C, No. 9, pp. 1173-1177, (2013).

[0005] Japanese Patent Application Laid-Open No. 2021-76632

[0006] According to the technology described in Patent Document 1, in order to align the rotation angle of the MCF, a magnetic material outlet is precisely positioned at a predetermined position in the rotation direction relative to the core position of the MCF, and the magnetic material is applied together with the coating layer. However, when an optical connector is fabricated using a ribbon fiber with an aligned MCF rotation angle, the magnetic material is also removed when the coating layer is removed. Therefore, when inserting the MCF into a multi-fiber optical connector, there is a problem in that end face observation is required to precisely align the core position.

[0007] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a magnetic-material-containing optical fiber, a magnetic-material-containing optical fiber ribbon, a magnetic-material-containing multi-fiber optical connector, and an aligning method for a magnetic-material-containing optical fiber, which are capable of precisely aligning core positions without observing the end faces when inserting and arranging multiple MCFs into a multi-fiber optical connector.

[0008] In order to solve the above-mentioned problems, a magnetic-material-containing optical fiber according to one aspect of the present disclosure comprises a core region, a magnetic region containing a magnetic material and arranged along the central axis of the core region, and a cladding region arranged to contain the core region and the magnetic region therein.

[0009] A magnetic-material-containing optical fiber ribbon according to an aspect of the present disclosure includes the above-described magnetic-material-containing optical fiber and a coating layer that coats the magnetic-material-containing optical fiber.

[0010] A magnetic-material-containing multi-fiber optical connector according to one aspect of the present disclosure includes the above-described magnetic-material-containing optical fiber and a ferrule to which a magnetic material is applied.

[0011] A method for aligning a magnetic-material-containing optical fiber according to one aspect of the present disclosure adjusts the rotational position of the core region relative to the central axis of the cladding region in the above-described magnetic-material-containing multi-core optical connector by using a magnetic force acting between the magnetic material contained in the magnetic region and the magnetic material contained in the ferrule.

[0012] According to the present disclosure, when inserting and arranging a plurality of MCFs into a multi-fiber optical connector, precise alignment of core positions can be performed without observing the end face.

[0013] FIG. 1 is a schematic diagram showing rotational alignment of a magnetic-material-containing optical fiber according to a first embodiment of the present disclosure. FIG. 2 is a diagram showing the appearance of a magnetic-material-containing multi-fiber optical connector according to a first embodiment of the present disclosure. FIG. 3 is a side cross-sectional view of the magnetic-material-containing multi-fiber optical connector according to a first embodiment of the present disclosure. FIG. 4 is a front cross-sectional view of the magnetic-material-containing multi-fiber optical connector according to a first embodiment of the present disclosure. FIG. 5 is a diagram showing an arrangement of components when a preform for the magnetic-material-containing optical fiber according to the first embodiment of the present disclosure is fabricated. FIG. 6 is a diagram showing a modified example of an arrangement of components when a preform for the magnetic-material-containing optical fiber according to the first embodiment of the present disclosure is fabricated. FIG. 7 is a diagram showing the configuration of an apparatus for manufacturing the magnetic-material-containing optical fiber according to the first embodiment of the present disclosure. FIG. 8 is a side cross-sectional view of a magnetic-material-containing multi-fiber optical connector according to a second embodiment of the present disclosure. FIG. 9 is a side cross-sectional view of a magnetic-material-containing multi-fiber optical connector according to a third embodiment of the present disclosure. FIG. 10 is a front cross-sectional view of a magnetic-material-containing multi-fiber optical connector according to a third embodiment of the present disclosure. FIG. 11 is a front cross-sectional view of a V-groove included in a magnetic-material-containing multi-fiber optical connector according to a fourth embodiment of the present disclosure. FIG. 12 is a side cross-sectional view of a magnetic-material-containing multi-fiber optical connector according to a fifth embodiment of the present disclosure.

[0014] Next, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description, the same components are designated by the same reference numerals and redundant description will be omitted.

[0015] [Description of First Embodiment] Fig. 1 is a schematic diagram showing rotational alignment of a magnetic material-containing optical fiber according to a first embodiment of the present disclosure. The magnetic material-containing optical fiber FB includes a core region RA, a magnetic region MR, and a cladding region CL. The core region RA includes a magnetic material and is arranged along the central axis of the core region RA. The cladding region CL is arranged to include the core region RA and the magnetic region MR therein.

[0016] 1, each magnetic-material-containing optical fiber FB is shown to have four core regions RA and two magnetic regions MR. The number of core regions RA and magnetic regions MR is not limited to the example given here. The magnetic-material-containing optical fiber FB has at least two core regions RA and at least one magnetic region MR.

[0017] In the magnetic-substance-containing optical fiber FB, the magnetic region MR is arranged at a position eccentric from the central axis of the cladding region CL (the central axis of the outer periphery of the magnetic-substance-containing optical fiber FB). Alternatively, the arrangement of the magnetic regions MR in the magnetic-substance-containing optical fiber FB may be determined so that another magnetic region MR is not arranged at a position that is point-symmetric with respect to the position where one magnetic region MR is arranged with respect to the central axis of the cladding region CL.

[0018] 1 shows four core regions RA arranged at equal intervals around the central axis of the cladding region CL, while two magnetic regions MR are arranged unequal intervals and are arranged close to a specific core region RA. By arranging the magnetic regions MR at positions eccentric to the central axis of the cladding region CL in this way, when an external magnetic field acts on the magnetic-substance-containing optical fiber FB, the magnetic regions MR are aligned in a predetermined direction.

[0019] When an external magnetic field acts on the magnetic-material-containing optical fiber FB, the magnetic-material-containing optical fiber FB changes from the pre-alignment state ST1 in Fig. 1 to the post-alignment state ST2. In the post-alignment state ST2, an external magnetic field acting in the vertical direction of the page acts on the magnetic-material-containing optical fiber FB. The external magnetic field attracts the magnetic region MR in a specific direction, thereby adjusting the rotational position of the core region RA with respect to the central axis of the cladding region CL.

[0020] 2 is a diagram showing the appearance of a magnetic-material-containing multi-fiber optical connector according to a first embodiment of the present disclosure. The magnetic-material-containing optical fiber ribbon TP includes a magnetic-material-containing optical fiber FB and a coating layer CV that coats the magnetic-material-containing optical fiber FB. The magnetic-material-containing multi-fiber optical connector 10 includes the magnetic-material-containing optical fiber FB and a ferrule 11 to which a magnetic material MG is applied.

[0021] The manner in which the magnetic material MG is applied to the ferrule 11 will be described later. The shape of the ferrule 11 is not limited to the example given here. The shape of the magnetic material-containing multi-fiber optical connector 10 is not limited to the shape shown in this embodiment. The magnetic material-containing multi-fiber optical connector 10 may be an MT connector or may be something else. Furthermore, the shape of the magnetic material MG is not limited to the shape shown in this embodiment.

[0022] The coating layer CV is removed from the end of the magnetic-material-containing optical fiber ribbon TP, exposing the magnetic-material-containing optical fiber FB. The exposed magnetic-material-containing optical fiber FB is inserted into the insertion hole SH of the ferrule 11, and the magnetic-material-containing optical fiber FB is arranged in the ferrule 11. When the magnetic-material-containing optical fiber FB is arranged in the ferrule 11, the magnetic-material-containing optical fiber FB is supported by a V-groove 13 inside the ferrule 11. The V-groove 13 has a groove with a V-shaped cross section that supports the magnetic-material-containing optical fiber FB.

[0023] 2 shows the guide hole GH and the insertion hole SH. The vicinity of the guide hole GH and the vicinity of the insertion hole SH require precise processing to suppress axial misalignment when aligning the core region RA of the magnetic-substance-containing optical fiber FB.

[0024] 3 and 4 are side and front cross-sectional views of the magnetic-material-containing multi-fiber optical connector according to the first embodiment of the present disclosure.

[0025] Note that Fig. 3 shows a cross-sectional view of the magnetic-material-containing multi-fiber optical connector 10 in a plane parallel to the YZ plane in Fig. 2. Fig. 4 shows a cross-sectional view of the magnetic-material-containing multi-fiber optical connector 10 in a plane parallel to the XZ plane in Fig. 2, and is a cross-sectional view of line A-A in Fig. 3.

[0026] As shown in Fig. 3, the magnetic material MG is disposed near the end (near the exit of the insertion hole SH) of the magnetic-material-containing optical fiber FB inserted into the magnetic-material-containing multi-fiber optical connector 10. In particular, as shown in Fig. 4, the magnetic material MG is disposed below the row of multiple magnetic-material-containing optical fibers FB.

[0027] The width of the magnetic material MG may be approximately the same as or greater than the width of the arrangement of the magnetic-material-containing optical fibers FB. Here, "width" refers to the X-axis direction in FIG. 1 .

[0028] When adjusting the rotational position of the core region RA with respect to the central axis of the cladding region CL, the magnetic substance-containing optical fiber FB is inserted into the insertion hole SH of the ferrule 11 .

[0029] Thereafter, the position of the magnetic region MR relative to the central axis of the cladding region CL is changed by the magnetic force acting between the magnetic material contained in the magnetic region MR of the magnetic-material-containing optical fiber FB and the magnetic material MG, and as a result, the rotational position of the core region RA relative to the central axis of the cladding region CL is adjusted.

[0030] Next, a method for manufacturing the magnetic material-containing optical fiber FB will be described. Fig. 5 is a diagram showing the arrangement of components when manufacturing a preform for the magnetic material-containing optical fiber according to the first embodiment of the present disclosure. Fig. 6 is a diagram showing a modified example of the arrangement of components when manufacturing a preform for the magnetic material-containing optical fiber according to the first embodiment of the present disclosure. Fig. 7 is a diagram showing the configuration of an apparatus for manufacturing the magnetic material-containing optical fiber according to the first embodiment of the present disclosure.

[0031] 5 shows a base material for the magnetic-material-containing optical fiber FB, in which four core regions RA are arranged in a square lattice pattern and five cladding regions CL are arranged between the core regions RA. One of the cladding regions CL incorporates a magnetic region MR. Glass particles are deposited around the cladding region CL to form the cladding region CLa. The glass particles are deposited using, for example, an outside vapor deposition (OVD) method. The cladding region CLa is integrated with the cladding region CL after drawing.

[0032] In the magnetic region MR arranged inside the cladding region CL, for example, a hole-punching method may be used to partially include magnetic powder in the cladding region CL. Alternatively, instead of including the magnetic region MR in the cladding region CL, the magnetic region MR may be arranged in a void that occurs during the preparation of the base material, as shown in FIG. 6. As long as the magnetic region MR is arranged in the cladding region CL corresponding to the core region RA, the magnetic region MR may be in any of a powder, fiber, or rod-like state. The magnetic region MR is not limited to the examples given here.

[0033] The magnetic-material-containing optical fiber FB is manufactured by drawing a preform having members arranged as shown in Fig. 5 or 6 using the magnetic-material-containing optical fiber manufacturing apparatus shown in Fig. 7. The magnetic-material-containing optical fiber manufacturing apparatus includes a drawing furnace 23, a cooling device 24, and a magnetization device 25.

[0034] The drawing furnace 23 heats the base material to a high temperature equal to or higher than its softening point and draws it into a thin spun fiber. The cooling device 24 cools the base material in the spun fiber state after drawing to produce a pre-magnetized magnetic-substance-containing optical fiber FB. The magnetization device 25 places the pre-magnetized magnetic-substance-containing optical fiber FB in a strong magnetic field and magnetizes the magnetic-substance-containing optical fiber FB.

[0035] The magnetization device 25 may be, for example, a device that magnetizes the magnetic-substance-containing optical fiber FB by disposing a strong magnet therein, or a device that magnetizes the magnetic-substance-containing optical fiber FB by a magnetic field generated by passing a current through a coil. The method of magnetizing the magnetic-substance-containing optical fiber FB is not limited to the examples given here.

[0036] When the magnetic material in the magnetic region MR arranged in the base material is heated above the Curie temperature during the drawing process, the magnetic moment becomes fragmented and the material becomes paramagnetic. Then, by applying strong magnetization during cooling, the magnetic moment can be aligned by thermoremanent magnetization. As a result, a magnetic-material-containing optical fiber FB having the properties of a magnetic material can be produced.

[0037] [Description of Second Embodiment] Fig. 8 is a side cross-sectional view of a magnetic-material-containing multi-fiber optical connector according to a second embodiment of the present disclosure. Fig. 8 shows a cross-sectional view of the magnetic-material-containing multi-fiber optical connector 10 taken along a plane parallel to the YZ plane, similar to Fig. 3 .

[0038] 8, the magnetic material MG is disposed near the end (near the exit of the insertion hole SH) of the magnetic-material-containing optical fiber FB inserted into the magnetic-material-containing multi-fiber optical connector 10. The magnetic material MG is disposed above the array of the magnetic-material-containing optical fibers FB. In particular, the magnetic material MG is disposed near the surface of the ferrule 11.

[0039] The vicinity of the guide holes GH and the vicinity of the insertion holes SH of the magnetic-material-containing multi-fiber optical connector 10 require precise machining to prevent axial misalignment when aligning the core region RA of the magnetic-material-containing optical fiber FB. On the other hand, the vicinity of the surface of the ferrule 11 does not require precise machining. Therefore, the verification cost for changing the dimensions of the ferrule 11 to arrange the magnetic material MG in the ferrule 11 can be reduced.

[0040] [Description of Third Embodiment] Fig. 9 is a side cross-sectional view of a magnetic-material-containing multi-fiber optical connector according to a third embodiment of the present disclosure. Fig. 10 is a front cross-sectional view of a magnetic-material-containing multi-fiber optical connector according to the third embodiment of the present disclosure.

[0041] 9 shows a cross-sectional view of the magnetic-material-containing multi-fiber optical connector 10 in a plane parallel to the YZ plane. Fig. 10 shows a cross-sectional view of the magnetic-material-containing multi-fiber optical connector 10 in a plane parallel to the XZ plane, and is a cross-sectional view of line B-B in Fig. 9.

[0042] 9 and 10 , the magnetic body MG is arranged on the opposite side of the V-groove 13 from the side on which the magnetic-material-containing optical fiber FB is arranged. That is, the magnetic body MG is arranged below the V-groove 13. The magnetic region MR inside the magnetic-material-containing optical fiber FB and the magnetic body MG of the ferrule 11 attract each other by magnetic force across the V-groove 13, thereby performing rotational alignment of the magnetic-material-containing optical fiber FB.

[0043] After inserting the magnetic-material-containing optical fiber FB into the ferrule 11, the magnetic-material-containing optical fiber FB is rotationally aligned on the upper surface of the V-groove 13. Then, with the rotational positions of the core regions RA aligned, the magnetic-material-containing optical fiber FB is inserted close to the end face of the ferrule 11 (the right end of the ferrule 11 shown in FIG. 9 ). After that, the magnetic-material-containing optical fiber FB is fixed with an adhesive.

[0044] According to this embodiment, rotational alignment can be performed using the magnetic force of the magnetic material in the V-groove 13, which has a relatively large space. As a result, rotational alignment is performed in a location where the frictional force between the magnetic-material-containing optical fiber FB and the ferrule 11 is relatively small, so that rotational alignment can be performed more reliably.

[0045] [Description of Fourth Embodiment] Fig. 11 is a front cross-sectional view of a V-groove included in a magnetic-material-containing multi-fiber optical connector according to a fourth embodiment of the present disclosure. Fig. 11 shows an example in which two magnetic materials MG are arranged in one V-groove 13. More specifically, the magnetic materials MG are provided on the support surface of the V-groove 13 that supports the magnetic-material-containing optical fiber FB.

[0046] This prevents the rotational position of the core region RA from shifting and fluctuating while the magnetic-material-containing optical fiber FB is supported in the V-groove 13. In particular, by arranging the magnetic material MG so as to sandwich the magnetic-material-containing optical fiber FB in one of the V-grooves 13, the rotational alignment of the magnetic-material-containing optical fiber FB can be more reliably performed. Furthermore, the magnetic-material-containing optical fiber FB can be reliably supported.

[0047] 12 is a side cross-sectional view of a magnetic-material-containing multi-fiber optical connector according to a fifth embodiment of the present disclosure. The magnetic-material-containing optical fiber FB is protruded from the end face of the ferrule 11 (the right end of the ferrule 11 shown in FIG. 12 ), and a magnetic material MG is brought close to the protruding portion FBa, thereby performing rotational alignment of the magnetic-material-containing optical fiber FB. The magnetic-material-containing optical fiber FB is then fixed with an adhesive.

[0048] Alternatively, the protruding portion FBa may be removed with a cutter or the like, or the protruding amount may be made uniform by polishing.

[0049] The outside of the ferrule 11 is a location that does not require precision machining, and therefore the cost of verifying changes to the dimensions of the ferrule 11 in order to arrange the magnetic body MG in the ferrule 11 can be reduced.

[0050] [Effects of the embodiment] As described above in detail, the magnetic material-containing optical fiber according to the present embodiment comprises a core region, a magnetic region that contains a magnetic material and is arranged along the central axis of the core region, and a cladding region that is arranged to contain the core region and the magnetic region therein.

[0051] This allows precise core alignment without observing the end face when inserting and arranging multiple MCFs into a multi-core optical connector, and also eliminates the need for a driving device for rotating the magnetic-material-containing optical fiber for core alignment.

[0052] In the magnetic-material-containing optical fiber according to this embodiment, the magnetic region may be disposed at a position eccentric from the central axis of the cladding region. This allows the magnetic region to be aligned in a predetermined direction based on the external magnetic field when an external magnetic field acts on the magnetic-material-containing optical fiber. As a result, precise core alignment can be achieved without observing the end face.

[0053] Furthermore, in the magnetic-substance-containing optical fiber according to this embodiment, no other magnetic region may be disposed at a position that is point-symmetrical with respect to the central axis of the cladding region with respect to the position where one magnetic region is disposed, so that when an external magnetic field acts on the magnetic-substance-containing optical fiber, the magnetic regions are more reliably aligned in a predetermined direction based on the external magnetic field.

[0054] Furthermore, the magnetic-material-containing optical fiber ribbon according to this embodiment includes the above-described magnetic-material-containing optical fiber and a coating layer that coats the magnetic-material-containing optical fiber. This allows precise core alignment without end face observation after the magnetic-material-containing optical fiber ribbon is inserted into a multi-fiber optical connector. Furthermore, since the magnetic-material-containing optical fiber FB itself includes a magnetic region, the core alignment can be performed more precisely than when the magnetic-material-containing optical fiber is aligned via a coating layer.

[0055] Furthermore, the magnetic-material-containing multi-fiber optical connector according to this embodiment includes the above-described magnetic-material-containing optical fiber and a ferrule to which a magnetic material is applied, whereby after inserting and arranging the magnetic-material-containing optical fiber FB into the multi-fiber optical connector, precise alignment of the core positions can be performed without observing the end face.

[0056] In the magnetic-material-containing multi-fiber optical connector according to the present embodiment, the ferrule may have a V-groove that supports the magnetic-material-containing optical fiber, and a magnetic material may be applied to the support surface of the V-groove. This prevents the rotational position of the core region from shifting and fluctuating while the magnetic-material-containing optical fiber is supported in the V-groove.

[0057] Furthermore, the alignment method for the magnetic-material-containing optical fiber according to this embodiment adjusts the rotational position of the core region relative to the central axis of the cladding region by using the magnetic force acting between the magnetic material contained in the magnetic region and the magnetic material contained in the ferrule in the magnetic-material-containing multi-fiber connector described above. This allows precise alignment of the core positions when inserting and arranging multiple MCFs into the multi-fiber connector without observing the end faces.

[0058] Although the contents of the present disclosure have been described above based on the embodiments, the present disclosure is not limited to these descriptions, and various modifications and improvements are possible, which will be apparent to those skilled in the art. The descriptions and drawings that form part of this disclosure should not be understood as limiting the present disclosure. Various alternative embodiments, examples, and operating techniques will be apparent to those skilled in the art from this disclosure.

[0059] Of course, the present disclosure includes various embodiments not described herein. Therefore, the technical scope of the present disclosure is defined only by the invention-specifying matters according to the scope of the claims that are appropriate from the above description.

[0060] REFERENCE SIGNS LIST 10 Magnetic-material-containing multi-core optical connector 11 Ferrule 12 Hole 13 V-groove 23 Drawing furnace 24 Cooling device 25 Magnetization device CL Cladding region CV Coating layer FB Magnetic-material-containing optical fiber GH Guide hole MG Magnetic material MR Magnetic region RA Core region SH Insertion hole ST1 State before alignment ST2 State after alignment TP Magnetic-material-containing optical fiber ribbon

Claims

1. A magnetic-containing optical fiber comprising: a core region; a magnetic region containing a magnetic material and arranged along the central axis of the core region; and a cladding region arranged to contain the core region and the magnetic region therein.

2. The magnetic material-containing optical fiber according to claim 1, wherein the magnetic region is disposed at a position eccentric to the central axis of the cladding region.

3. The magnetic material-containing optical fiber according to claim 1, wherein the other magnetic regions are not arranged at positions that are point-symmetrical with respect to the central axis of the cladding region with respect to the position where one of the magnetic regions is arranged.

4. A magnetic material-containing optical fiber ribbon comprising: the magnetic material-containing optical fiber according to claim 1; and a coating layer that coats the magnetic material-containing optical fiber.

5. A magnetic material-containing multi-core optical connector comprising: the magnetic material-containing optical fiber according to claim 1; and a ferrule to which a magnetic material is applied.

6. A magnetic material-containing multi-core optical connector according to claim 5, wherein the ferrule has a V-groove that supports the magnetic material-containing optical fiber, and a magnetic material is applied to the supporting surface of the V-groove.

7. A method for aligning a magnetic-material-containing optical fiber, in a magnetic-material-containing multi-core optical connector as described in claim 5 or 6, comprising adjusting the rotational position of the core region relative to the central axis of the cladding region by a magnetic force acting between the magnetic material contained in the magnetic region and the magnetic material contained in the ferrule.

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