Alignment device and alignment method

Abstract

An alignment device (101) that aligns a plurality of MCFs (2) included in a ribbon cable (1) comprises: alignment mechanisms (3) that are provided to the MCFs (2) separated individually from the ribbon cable (1), and that align the respective MCFs (2); and an interval converter (4) that changes the interval between the MCFs (2) aligned by the alignment mechanisms (3). The position of each of the alignment mechanisms (3) is set such that the distance from an end surface (P2) of the alignment mechanism (3) to an end part (P1) of the corresponding MCF (2) is constant among the MCFs (2).

Description

Alignment Device and Alignment Method

[0001] The present disclosure relates to an alignment device and an alignment method for aligning a multi-core optical fiber.

[0002] Non-Patent Document 1 discloses a multi-core optical fiber (hereinafter abbreviated as "MCF") that employs a cladding diameter highly compatible with existing optical fibers. Since an MCF has a plurality of core regions, alignment needs to be performed when connecting to devices such as connectors. "Alignment" refers to a process of adjusting the positions of each core included in the MCF so that they reach predetermined positions by rotating the MCF around the axis in the longitudinal direction by a certain angle.

[0003] When aligning an MCF, an alignment mechanism that can rotate the MCF around the axis is used. Specifically, one alignment mechanism is attached to one MCF, and alignment is performed by rotating the MCF while observing the MCF from the end face direction or the side face direction. Also, when connecting a plurality of MCFs to a multi-core connector, alignment is individually performed for each MCF, and the tip of the MCF after alignment is connected to the multi-core connector.

[0004] T. Matsuiet al., "Design and applicability of multi-core fiberswith standard claddingdiameter", J. Lightwave Technol., vol. 38, pp. 6065,2020.

[0005] When aligning a plurality of MCFs included in a ribbon optical fiber, it is required to align all the MCFs simultaneously. A ribbon optical fiber refers to a cable having a tape structure in which a plurality of MCFs are arranged in parallel and coated. For example, when connecting an MCF of a ribbon optical fiber to a silica-based planar optical waveguide circuit, or when fusion-connecting MCFs of a ribbon optical fiber to each other, it is necessary to align each MCF included in the ribbon optical fiber simultaneously.

[0006] Each MCF (Multi-Chip Fiber) contained in the tape fiber is arranged in parallel at intervals of several hundred micrometers. Therefore, it is difficult to align each MCF while maintaining the spacing between them. Furthermore, if each MCF is separated from the tape fiber and the spacing between them is increased before aligning, it becomes difficult to return the spacing between the MCFs to their original state after aligning.

[0007] This disclosure has been made in view of the above circumstances, and its purpose is to provide a centering device and centering method that can center multiple MCFs included in a tape core wire with simple operation, and return the spacing between each MCF after centering to its original state.

[0008] A centering device according to one aspect of the present disclosure is a centering device for centering a plurality of multicore optical fibers included in a ribbon fiber, and comprises a centering mechanism provided on each multicore optical fiber separated as a single core from the ribbon fiber for centering each multicore optical fiber, and a spacing converter for changing the spacing between each multicore optical fiber centered by the centering mechanism, wherein the position of each centering mechanism is set such that the distance from the end face of each centering mechanism to the end of each multicore optical fiber is constant for each multicore optical fiber.

[0009] A method for aligning multiple multicore optical fibers included in a ribbon fiber is a method for aligning multiple multicore optical fibers included in a ribbon fiber, wherein each multicore optical fiber is separated from the ribbon fiber into single cores, each separated multicore optical fiber is temporarily fixed to an alignment mechanism, each temporarily fixed multicore optical fiber is inserted into a spacing converter, the ends of each multicore optical fiber are adjusted to coincide, and each multicore optical fiber is aligned by the alignment mechanism.

[0010] According to this disclosure, it becomes possible to align multiple MCFs contained in a tape core wire with a simple operation, and to return the spacing between each MCF to its original state after alignment.

[0011] Figure 1 is a schematic diagram illustrating the centering device and the tape core to be centered according to the first embodiment. Figure 2 is a schematic diagram illustrating a sliding mechanism that slides the centering mechanism in the axial direction. Figure 3 is a schematic diagram illustrating a moving stage that moves the spacing converter in a direction perpendicular to the axial direction. Figure 4 is a schematic diagram illustrating the centering device and the tape core to be centered according to the second embodiment. Figure 5 is a schematic diagram illustrating the centering device and the tape core to be centered according to the third embodiment. Figure 6 is a schematic diagram illustrating the centering device and the tape core to be centered according to the fourth embodiment.

[0012] Embodiments will be described below with reference to the drawings. However, this disclosure is not limited to the embodiments shown below. These embodiments are merely illustrative, and this disclosure can be implemented in various modified and improved forms based on the knowledge of those skilled in the art. In this specification and in the drawings, components with the same reference numerals refer to the same components.

[0013] [Description of the First Embodiment] Figure 1 is a schematic diagram showing the alignment device 101 and the ribbon fiber 1 to be aligned according to the first embodiment. "Ribbon fiber" refers to a cable that forms a ribbon structure by installing and covering multiple multicore optical fibers (hereinafter abbreviated as "MCF") in parallel. In this embodiment, the case in which the ribbon fiber 1 has four MCFs 2 will be described. Each of the four MCFs 2 has multiple cores. The number of cores in each MCF 2 is, for example, four. Also, below, as shown in Figure 1, the longitudinal direction of the MCF 2 will be defined as the "axial direction".

[0014] The alignment device 101 according to this embodiment includes a function to adjust the path length of each MCF2 and a function to adjust the spacing between each MCF2, thereby aligning the end faces of each MCF2 and setting the spacing between each MCF2 after alignment to be the same as the spacing of the MCF2 included in the tape core wire 1.

[0015] As shown in Figure 1, the alignment device 101 according to this embodiment includes four alignment mechanisms 3 (3-1 to 3-4) and a spacing converter 4. In the following, when each alignment mechanism is specifically identified, it will be indicated with a suffix such as "alignment mechanism 3-1," and when not specifically identified or when referring to them collectively, it will be indicated without a suffix as "alignment mechanism 3."

[0016] The alignment mechanism 3 has a cylindrical shape with an insertion portion that extends in the axial direction. The MCF2 is inserted into the insertion portion of the alignment mechanism 3. That is, each of the four alignment mechanisms 3-1 to 3-4 has one of the four MCF2s contained in the tape core wire 1 that has been separated into individual cores inserted into it. The four alignment mechanisms 3 are arranged so that their central axes are aligned on the same plane. The alignment mechanism 3 aligns the MCF2 by rotating it about the axial direction or by offsetting it in a direction perpendicular to the axial direction, with the MCF2 inserted into the insertion portion.

[0017] The spacing converter 4 takes each MCF2 that has passed through each alignment mechanism 3 as input and changes the spacing of each MCF2. Specifically, the spacing converter 4 narrows the spacing of each MCF2, which has been separated into single cores and widened to the spacing of each alignment mechanism 3, to the spacing of each MCF2 contained in the tape core 1. That is, each MCF2 taken out from the output side of the spacing converter 4 is made to be approximately the same as the spacing of each MCF2 contained in the tape core 1. Note that the spacing of the MCF2 on the input surface of the spacing converter 4 is about a few centimeters, and the spacing of the MCF2 on the output surface is several hundred micrometers. Therefore, the spacing of the MCF2 on the input surface of the spacing converter 4 is about a hundred times the spacing of the MCF2 on the output surface. Figure 1 is shown at a different scale to facilitate understanding.

[0018] The spacing d1 of each MCF2 input to the spacing converter 4 is determined by the outer diameter (approximately several centimeters) of the self-aligning mechanism 3. Specifically, the spacing d1 is set to be the same as, or slightly larger than, the outer diameter of the self-aligning mechanism 3. Note that the spacing d1 may be set to a value unrelated to the outer diameter of the self-aligning mechanism 3, depending on the application.

[0019] Next, we will describe the procedure for aligning the four MCF2 contained in the tape core 1 using the alignment device 101 configured as described above, returning the spacing between each MCF2 to its original spacing (the spacing in the tape core 1), and aligning the end faces of each MCF2.

[0020] First, the tape core 1 is cut using a fiber cutter or the like. Next, the tip of the cut tape core 1 is separated into individual cores. By separating each MCF2 contained in the tape core 1 into individual cores, four MCF2 are exposed. Note that the order of cutting the tape core 1 and separating the individual cores may be reversed. That is, each MCF contained in the tape core 1 may be cut together, or each MCF2 may be cut one by one after being separated into individual cores. If each MCF2 is cut one by one, it is preferable to make the length of each MCF2 after separation the same.

[0021] Next, each MCF2 that has been separated into individual cores is temporarily fixed to each alignment mechanism 3. Furthermore, the temporarily fixed MCF2 is inserted into the space converter 4. After that, the axial position of the temporarily fixed MCF2 is adjusted and fixed in each alignment mechanism 3. That is, each alignment mechanism 3 is fixed so that the MCF2 does not move in the axial direction. The alignment mechanism 3 should be structured to fix the MCF2 inserted into the insertion part so that it does not rotate relative to it. For example, the MCF2 can be clamped using rubber or the like within the insertion part of the alignment mechanism 3. In this case, it is desirable that the distance from the end P1 of the MCF2 to the end face P2 of each alignment mechanism 3 is the same.

[0022] The spacing between each MCF1 contained in the tape core 1 is generally several hundred μm. Therefore, the path length of the MCF2 within the spacing converter 4 is shorter the closer the MCF2 is to the axial centerline C1, unless it meanders internally. Specifically, the distance Lb1 of the MCF2 passing through the alignment mechanism 3-1 to the end P1 within the spacing converter 4 is shorter than the distance Lb2 of the MCF2 passing through the alignment mechanism 3-2 to the end P1 within the spacing converter 4.

[0023] Similarly, if Lb3 is the distance that the MCF2 passing through the alignment mechanism 3-3 travels through the spacing converter 4 to reach end P1, and Lb4 is the distance that the MCF2 passing through the alignment mechanism 3-4 travels through the spacing converter 4 to reach end P1, then Lb1 = Lb4, Lb2 = Lb3, and Lb1, Lb4 > Lb2, Lb3. In this embodiment, the axial position of each alignment mechanism 3 is adjusted in order to make the distance from the end face P2 of each alignment mechanism 3 to end P1 of the MCF2 the same. The distance from the end face P2 of each alignment mechanism 3 to the input surface P3 of the spacing converter 4 is set to La1 to La4.

[0024] Specifically, let La1 be the distance from end face P2 to input face P3 of the alignment mechanism 3-1, La2 be the distance from end face P2 to input face P3 of the alignment mechanism 3-2, La3 be the distance from end face P2 to input face P3 of the alignment mechanism 3-3, and La4 be the distance from end face P2 to input face P3 of the alignment mechanism 3-4. Furthermore, if L1 = La1 + Lb1, L2 = La2 + Lb2, L3 = La3 + Lb3, and L4 = La4 + Lb4, then the settings are made so that L1 = L2 = L3 = L4 holds true. By doing this, the path lengths of each MCF2 can be made the same.

[0025] It is preferable to set the distance from the end face P2 of each centering mechanism 3 to the input surface P3 of the spacing converter 4 symmetrically, using the axial center line C1 of the spacing converter 4 as a reference. Specifically, it is preferable to set the distances La1 and La4 shown in Figure 1 to be the same, and the distances La2 and La3 to be the same.

[0026] Each centering mechanism 3 can be operated electrically or manually. A commercially available centering mechanism 3, for example, can be a rotary stage. The spacing converter 4 is preferably made of plastic or metal. If a bent portion is provided in the spacing converter 4, it is desirable that the curvature be such that it can follow the centering of the centering mechanism 3.

[0027] Furthermore, a mechanism for adjusting the axial position of each MCF2 may be added to align the end P1 of each MCF2. Alternatively, a function for adjusting the axial position may be added to the centering mechanism 3. A manual stage or an electric stage can be used as the mechanism for adjusting the axial position of the MCF2.

[0028] For example, as shown in Figure 2, a slide mechanism 11 may be mounted on each centering mechanism 3, and the axial position of each centering mechanism 3 may be adjusted by operating the slide mechanism 11. This makes it possible to easily adjust the distances La1, La2, La3, and La4 shown in Figure 1. The slide mechanism 11 is an example of a slide mechanism that slides at least one of the centering mechanisms 3 in the longitudinal direction (axial direction) of the MCF2.

[0029] Cameras may be installed at appropriate locations near each alignment mechanism 3, and the alignment of the end faces of the MCF2 may be confirmed based on the images captured by the cameras. Alignment may also be performed while observing the axial position of the MCF2 using the camera images.

[0030] It is desirable to match the height of the MCF2 to the component to which it will be connected (quartz plenary circuit, tape core wire, etc.). Specifically, as shown in Figure 3, a moving stage 12 for adjusting the height of the spacing converter 4 may be installed, and the height of the spacing converter 4 may be adjusted by driving the moving stage 12. The moving stage 12 moves the spacing converter 4 in a direction perpendicular to the central axis of the centering mechanism 3.

[0031] When connecting the MCF2 to a quartz plenary circuit or the like, light may be incident from one end of the MCF2, a power meter may be placed on the other end, and the system may be aligned to maximize the light intensity. When checking whether the end faces of the MCF2 are aligned using images captured by a camera, the position of the end faces may be measured from the side of each alignment mechanism 3.

[0032] The portion of the space converter 4 through which the MCF2 passes may be cylindrical, or it may be a V-groove with a cover placed over it from above. When cutting the tape core wire 1 and MCF2, it is desirable to remove the coating beforehand. After removing the coating, it is desirable to clean them with ethanol, an ultrasonic cleaner, or the like.

[0033] As described above, the alignment device 101 according to the first embodiment is an alignment device 101 for aligning a plurality of MCF2 (multicore optical fibers) included in a tape core 1, and comprises an alignment mechanism 3 provided on each MCF2 separated as a single core from the tape core 1 for aligning each MCF2, and a spacing converter 4 for changing the spacing between each MCF2 aligned by the alignment mechanism 3, and the position of each alignment mechanism 3 is set such that the distance from the end face P2 of each alignment mechanism 3 to the end P1 of each MCF2 is constant for each MCF2.

[0034] The alignment device 101 according to this embodiment makes it possible to easily align each MCF2 by operating the alignment mechanism 3 installed on each MCF2 that has been separated individually from the tape core wire 1. Furthermore, it is possible to align the end faces of each MCF2 when aligning them, and to set the spacing between each MCF2 after alignment to be the same as the spacing between the MCF2 included in the tape core wire 1. As a result, it becomes possible to align each MCF2 with high precision. In addition, it is possible to prevent the MCF2 from buckling when axial stress is applied to the MCF2.

[0035] Since each alignment mechanism 3 is arranged parallel to each other and their central axes are aligned on the same plane, the distance from the end face P2 of each alignment mechanism 3 to the end face P1 of the MCF2 can be easily adjusted by manipulating the axial position of each alignment mechanism 3. Therefore, each MCF2 can be connected to a silica-based planar optical circuit or the like while maintaining its tape structure.

[0036] In other words, because the outer diameter of the alignment mechanism 3 is extremely large compared to the outer diameter of the MCF2, it was difficult to arrange the alignment mechanism 3 in parallel with the spacing of the MCF2 included in the tape core wire 1. In contrast, by adopting the alignment device 101 according to this embodiment, even when the alignment mechanism 3 is arranged in parallel, it becomes possible to draw out the aligned MCF2 at the same spacing as the tape core wire 1.

[0037] [Description of the Second Embodiment] Next, a second embodiment will be described. Figure 4 is a schematic explanatory diagram showing the alignment device 102 and the tape core wire 1 to be aligned according to the second embodiment. As shown in Figure 4, the alignment device 102 according to the second embodiment includes four alignment mechanisms 3 (3-1 to 3-4) and a spacing converter 4.

[0038] Similar to the first embodiment described above, the alignment mechanism 3 has a cylindrical shape with an insertion portion that extends in the axial direction. The MCF2 is inserted through the insertion portion of the alignment mechanism 3. That is, each of the four alignment mechanisms 3-1 to 3-4 has one of the four MCF2s contained in the tape core wire 1 that has been separated into individual cores inserted through it.

[0039] When viewed from the axial direction, each of the four alignment mechanisms 3 is arranged in close contact with each other at each corner of the rectangle. That is, the end faces of each alignment mechanism 3 are located on a plane perpendicular to the axial direction, and are arranged to be equidistant from an arbitrary point (reference point) set on that plane.

[0040] The alignment mechanism 3 aligns the MCF2 by rotating it around its axial direction while the MCF2 is inserted into the insertion section. The MCF2 on the output side of the alignment mechanism 3 is input to the spacing converter 4, as in the first embodiment described above, and the spacing between each MCF2 is changed to be the same as that of the tape core wire 1.

[0041] When installing five or more self-aligning mechanisms 3, it is preferable to arrange each self-aligning mechanism 3 radially at equal angles with respect to a reference point on a plane perpendicular to the axial direction.

[0042] The spacing converter 4 may be manufactured in a planar or three-dimensional manner. To align the ends P1 of each MCF2, the axial position of each centering mechanism 3 may be adjusted, or the path length of each MCF2 within the spacing converter 4 may be adjusted.

[0043] As a method of three-dimensionally manufacturing the interval converter 4, a 3D printer can be used. It is preferable to use a metal material as the material of the 3D printer. The tape core wire 1 desirably has an intermittent tape structure in order to arrange four single-core separated MCF2s at each corner of a square.

[0044] Thus, in the centering device 102 according to the second embodiment, it is possible to achieve miniaturization as compared with the case where the centering mechanisms 3 are arranged in parallel on a plane. In addition, since the radius of curvature of the path of the MCF2 in the interval converter 4 can be increased, it is easy to make the MCF2 follow the rotation when the centering mechanism 3 is rotated.

[0045] That is, inside the interval converter 4, it is necessary to bend the MCF2, and the larger the radius of curvature at this bent portion, the easier it is to operate the MCF2. In the centering device 102 according to the second embodiment, since the lengths of the respective MCF2s from the end face P2 of the centering mechanism 3 to the input face P3 of the interval converter 4 are equal, the radius of curvature in the interval converter 4 can be increased, so that the path length can be easily adjusted.

[0046] [Description of the Third Embodiment] Next, the third embodiment will be described. FIG. 5 is an explanatory diagram schematically showing a centering device 103 according to the third embodiment and a tape core wire 1 to be centered. As shown in FIG. 5, the centering device 103 according to the third embodiment includes four centering mechanisms 3 (3-1 to 3-4) and an interval converter 4.

[0047] Similar to the first embodiment described above, the centering mechanism 3 has a cylindrical shape in which an insertion portion extending in the axial direction is formed. The MCF2 is inserted into the insertion portion of the centering mechanism 3. That is, each of the four centering mechanisms 3-1 to 3-4 is inserted with each of the four MCF2s obtained by single-core separation of the four MCF2s included in the tape core wire 1.

[0048] The output-side end faces of the four centering mechanisms 3 are set to be equidistant from the reference point P10 on the input face of the interval converter 4. The four interval converters 4 are arranged along an arc centered on the reference point P10. That is, each centering mechanism 3 is arranged at a position having the same distance from the reference point P10 set on the input face of the interval converter 4.

[0049] The spacing converter 4 may be straight along the path of all MCF2, or it may have a large radius of curvature so that it can follow the rotation of the centering mechanism 3. In the centering device 103 according to the third embodiment, since the length of each MCF2 from the end face P2 of the centering mechanism 3 to the input face P3 of the spacing converter 4 is equal, the path length in the spacing converter 4 can be easily adjusted.

[0050] [Description of the Fourth Embodiment] Next, the fourth embodiment will be described. Figure 6 is a schematic explanatory diagram showing the alignment device 104 and the tape core wire 1 to be aligned according to the fourth embodiment. As shown in Figure 6, the alignment device 104 according to this embodiment is equipped with four alignment mechanisms 3 (3-1 to 3-4) and a spacing converter 4.

[0051] Similar to the first embodiment described above, the alignment mechanism 3 has a cylindrical shape with an insertion portion that extends in the axial direction. The MCF2 is inserted through the insertion portion of the alignment mechanism 3. That is, each of the four alignment mechanisms 3-1 to 3-4 has one of the four MCF2s contained in the tape core wire 1 that has been separated into individual cores inserted through it.

[0052] The centering device 104 according to the fourth embodiment differs from the first embodiment described above in that, instead of installing each centering mechanism 3 in parallel on a single plane, they are arranged offset in a direction perpendicular to the axial direction. That is, each centering mechanism 3 is arranged such that its end face is located on a plane perpendicular to the axial direction of the centering mechanism 3, and is offset in a direction perpendicular to the axial direction so that the distance to the end P1 of the MCF2 is constant.

[0053] Specifically, the alignment mechanisms 3-2 and 3-3 corresponding to the MCF2 passing through the centerline C1 of the spacing converter 4 are set to have a larger offset in the direction perpendicular to the axial direction than the alignment mechanisms 3-1 and 3-4 corresponding to the MCF2 passing at a position further away from the centerline C1. This configuration makes it possible to set the path length from the end face P2 of each alignment mechanism 3 to the end P1 of each MCF2 to be constant.

[0054] As a result, similar to the first embodiment, each MCF2 can be easily aligned by operating the alignment mechanism 3 installed on each MCF2 that has been separated from the tape core 1. Furthermore, it becomes possible to align the end faces of each MCF2 when performing alignment, and to set the spacing between each MCF2 after alignment to the same spacing as the MCF2 included in the tape core 1. In addition, by offsetting the alignment mechanism 3 in a direction perpendicular to the axial direction, it becomes possible to miniaturize the device.

[0055] The spacing converter 4 may be manufactured in a planar or three-dimensional manner. To align the end P1 of the MCF2, the position of the centering mechanism 3 may be adjusted, or the path length of the spacing converter 4 may be adjusted.

[0056] This disclosure is not limited to the embodiments described above, and numerous modifications are possible within the scope of its essence.

[0057] 1. Ribbon fiber 2. Multicore optical fiber (MCF) 3. (3-1 to 3-4) Alignment mechanism 4. Spacing converter 11. Slide mechanism 12. Moving stage 101, 102, 103, 104. Alignment device C1. Centerline

Claims

1. A centering device for centering multiple multicore optical fibers contained in a ribbon fiber, comprising: a centering mechanism provided on each multicore optical fiber separated as a single core from the ribbon fiber for centering each multicore optical fiber; and a spacing converter for changing the spacing between each multicore optical fiber centered by the centering mechanism, wherein the position of each centering mechanism is set such that the distance from the end face of each centering mechanism to the end of each multicore optical fiber is constant for each multicore optical fiber.

2. The centering device according to claim 1, wherein each of the centering mechanisms is arranged such that its central axis lies on the same plane.

3. The alignment device according to claim 2, wherein each of the alignment mechanisms is set in the spacing converter and is arranged symmetrically with respect to a center line that faces the axial direction of the alignment mechanism.

4. The alignment device according to claim 2, wherein each of the alignment mechanisms is positioned at the same distance from a reference point set on the input surface of the spacing converter.

5. The centering device according to claim 1, wherein each of the centering mechanisms has an end face located on a plane perpendicular to the axial direction of the centering mechanism and is arranged to be equidistant from a reference point set on the plane.

6. The alignment device according to claim 1, wherein each of the alignment mechanisms is arranged such that its end face lies on a plane perpendicular to the axial direction of the alignment mechanism, and the distance to the end face of the multicore optical fiber is constant by offsetting in a direction perpendicular to the axial direction.

7. The alignment device according to claim 1, further comprising at least one of the following: a sliding mechanism for sliding at least one of the alignment mechanisms in the longitudinal direction of the multicore optical fiber; and a moving stage for moving the spacing converter in a direction perpendicular to the central axis of the alignment mechanism.

8. A method for aligning multiple multicore optical fibers contained in a ribbon fiber, comprising: separating each multicore optical fiber from the ribbon fiber; temporarily fixing each separated multicore optical fiber to an alignment mechanism; inserting each temporarily fixed multicore optical fiber into a spacing converter; adjusting so that the ends of each multicore optical fiber coincide; and aligning each multicore optical fiber using the alignment mechanism.

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