Method for manufacturing multicore optical fiber connector, and multicore optical fiber connector

Abstract

According to this method for manufacturing a multicore optical fiber connector and this multicore optical fiber connector, a reference connector ferrule (14) and a ferrule member (10) are connected, a light source is connected to one core included in a first multicore fiber (15) fixed to the reference connector ferrule (14), and a light receiver is connected to one core included in a second multicore fiber (17) installed in the ferrule member (10). The second multicore fiber (17) is suctioned via a suction hole (21) provided in a groove (11) of the ferrule member (10), and the second multicore fiber (17) is disposed in the groove (11) in a state in which the second multicore fiber (17) is rotatable around the axis thereof. The power of light delivered from the light source via the first multicore fiber (15) and the second multicore fiber (17) is acquired by the light receiver, and the positioning of the second multicore fiber (17) around the axis thereof with respect to the groove (11) is performed on the basis of the power.

Description

Method for manufacturing a multi-fiber optical fiber connector, and multi-fiber optical fiber connector

[0001] The present disclosure relates to a method for manufacturing a multi-fiber optical fiber connector and to a multi-fiber optical fiber connector.

[0002] With the spread of the Internet, the transmission capacity of information networks is expanding year by year. Methods for expanding the transmission capacity of optical fibers include time division multiplexing, wavelength division multiplexing, and space division multiplexing. In particular, space division multiplexing is a technology that realizes increased transmission capacity by using multicore fibers, which have multiple cores in one optical fiber, and few-mode fibers, which can multiplex multiple modes into one core.

[0003] In order to use multicore fibers in data centers and access networks, a multicore optical fiber connector capable of connecting multicore fiber cables is required to maintain the scalability of fiber cable installation. In multicore fiber connector technology, fiber cores are positioned off-center relative to the outer diameter of the fiber, so they need to be mounted by rotational alignment to achieve low connection loss. Non-Patent Document 1 discloses a mounting technique in which multicore fibers are arrayed after rotational alignment on a V-groove substrate and the multicore fiber array is inserted into an MT (Mechanically Transferable) ferrule as a method for reducing rotational misalignment to achieve low connection loss in multicore optical fiber connectors.

[0004] T. Morishima, Y. Saito, O. Shimakawa, K. Manabe, T. Nakanishi, T. Sano, and T. Hayashi, "Multicore fiber splicing technology," IEICE General University, BCI-1-5, 2021.

[0005] According to the technology described in Non-Patent Document 1, when aligning the core position of a multi-core fiber on a V-groove substrate, a desired core position is specified in position coordinates on the V-groove substrate using an image from a microscope or the like, and the multi-core fiber is rotated on the V-groove substrate while being adjusted so that the core position of the multi-core fiber is as close as possible to the specified core position. By adjusting the deviation between the core position of the multi-core fiber and the specified core position to be as small as possible, it is possible to suppress rotational deviation. However, since the amount of rotational deviation that can be suppressed depends on the image accuracy of the microscope or the like, there is a problem in that connection loss due to core position deviation such as rotational deviation increases.

[0006] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a method for manufacturing a multi-core optical fiber connector, and a multi-core optical fiber connector, which are capable of aligning a multi-core fiber without relying on the image accuracy in image observation and achieving a connection with low loss.

[0007] In order to solve the above-described problems, a method for manufacturing a multi-core optical fiber connector and a multi-core optical fiber connector according to one aspect of the present disclosure include connecting a reference connector ferrule and a ferrule member, connecting a light source to one core included in a first multi-core fiber fixed to the reference connector ferrule, and connecting a photodetector to one core included in a second multi-core fiber installed in the ferrule member. The second multi-core fiber is sucked through a suction hole provided in a groove of the ferrule member, and the second multi-core fiber is placed in the groove in a state where it can rotate freely around its axis. The power of light arriving from the light source via the first multi-core fiber and the second multi-core fiber is obtained by the photodetector, and the second multi-core fiber is positioned around its axis with respect to the groove based on the power.

[0008] According to the present disclosure, it is possible to align a multi-core fiber without relying on the image accuracy in image observation, and to achieve connection with low loss.

[0009] FIG. 1 is a perspective view showing an example of a ferrule member of a multi-core optical fiber connector according to the present disclosure. FIG. 2 is a perspective view showing an example of a ferrule of a multi-core optical fiber connector according to the present disclosure. FIG. 3 is a view showing an example of holding a second multi-core fiber in a ferrule member. FIG. 4 is a view showing a modified example of holding a second multi-core fiber in a ferrule member. FIG. 5 is a view showing an example of holding a first multi-core fiber in a reference connector ferrule. FIG. 6 is a perspective view showing a state in which a ferrule member and a reference connector ferrule are connected. FIG. 7 is a flowchart showing an example of a method of manufacturing a multi-core optical fiber connector according to the present disclosure. FIG. 8 is a top view showing an example of an arrangement of suction holes in a ferrule member. FIG. 9 is a top view showing a modified example of an arrangement of suction holes in a ferrule member.

[0010] 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.

[0011] 1 is a perspective view showing an example of a ferrule member of a multi-core optical fiber connector according to the present disclosure. The ferrule member 10 is a member for manufacturing ferrules that constitute the multi-core optical fiber connector. The ferrule member 10 is provided with grooves 11 in which multiple second multi-core fibers 17 can be placed, guide pin holes 12, and suction holes 21.

[0012] For example, the outer dimensions of the ferrule member 10 may be the same as the ferrule of an MT connector, also known as an F12-type multi-fiber connector. The outer dimensions of the ferrule member 10 may be the same as the ferrule of an MPO connector, also known as an F13-type multi-fiber connector. In this case, the end face of the MT ferrule may be formed at an angle (not shown). The MT ferrule may be built into an MPO plug housing, and the MPO plug may be connected within an MPO adapter. The multi-fiber connector is not limited to an MT connector or an MPO connector, as long as it can connect multiple optical fibers collectively and detachably.

[0013] 1, four grooves are provided as the grooves 11, each capable of accommodating four optical fibers. The number of grooves 11 need only correspond to the desired number of optical fibers to be arranged, and is not limited to the number given here. Furthermore, V-grooves having a V-shaped cross section are provided as the grooves 11. The cross section of the grooves 11 may be a semicircular or U-shaped cross section, or any other shape capable of accommodating optical fibers, and is not limited to the example given here.

[0014] 2 is a perspective view showing an example of a ferrule of a multi-core optical fiber connector according to the present disclosure. In particular, the ferrule constituting the multi-core optical fiber connector includes a ferrule member 10, a second multi-core fiber 17, and a fiber holding member 22. By installing the fiber holding member 22 in the ferrule member 10, the second multi-core fiber 17 is held in the ferrule member 10 more stably.

[0015] Fig. 3 is a diagram showing an example of holding the second multi-core fiber in the ferrule member. Fig. 4 is a diagram showing a modified example of holding the second multi-core fiber in the ferrule member. As shown in Figs. 3 and 4 , one second multi-core fiber 17 is arranged in each groove 11 of the ferrule member 10.

[0016] The fiber holding member 22 may have a rectangular shape relative to the ferrule end face as shown in Fig. 3, or may have a T-shape relative to the ferrule end face as shown in Fig. 4. The fiber holding member 22 is not limited to these shapes as long as it can stably hold the second multi-core fiber 17 in the ferrule member 10.

[0017] By adjusting the outer dimensions of the ferrule member 10, it is possible to make the shape produced by adhesively fixing the ferrule member 10 and the fiber holding member 22 equivalent to the outer dimensions of the desired multi-fiber connector. In particular, by adjusting the thickness of the ferrule member 10, it is possible to make the shape produced by adhesively fixing the ferrule member 10 equivalent to the outer dimensions of the desired multi-fiber connector.

[0018] In addition, by applying adhesive to the entire surface that comes into contact with the ferrule member 10 and adhesively fixing the T-shaped fiber holding member 22 shown in Figure 4, it is possible to more reliably adhesively fix the second multi-core fiber 17 to the ferrule member 10.

[0019] Although each second multicore fiber 17 has been shown to have a structure having four cores 20, the present invention is not limited to this example. For example, the number of cores in the second multicore fiber 17 may be two or more and is not limited to four. Furthermore, the arrangement of the cores 20 in the second multicore fiber 17 is not limited to a square shape. In addition, although an example in which four second multicore fibers 17 are installed is shown in Figures 3 and 4, the number of second multicore fibers 17 installed in the ferrule member 10 is not limited to four.

[0020] 5 is a diagram showing an example of holding a first multicore fiber in a reference connector ferrule. The reference connector ferrule 14 includes a plurality of first multicore fibers 15, and the core 16 of each first multicore fiber 15 is disposed at a desired position with respect to the center CP between the two guide pin holes 12. In this manner, the first multicore fiber 15 is fixed to the reference connector ferrule 14.

[0021] Although the embodiment shows a structure in which each first multicore fiber 15 has four cores 16, the present invention is not limited to this example. For example, the number of cores that the first multicore fiber 15 has may be two or more, and is not limited to four. In particular, the number of cores that the first multicore fiber 15 has is the same as the number of cores that the second multicore fiber 17 has.

[0022] Furthermore, the arrangement of the cores 16 in the first multicore fiber 15 is not limited to a square shape. In particular, the arrangement of the cores 16 in the first multicore fiber 15 is the same as the arrangement of the cores 20 in the second multicore fiber 17.

[0023] 5 shows an example in which four first multicore fibers 15 are installed in the reference connector ferrule 14, but the number of first multicore fibers 15 installed in the reference connector ferrule 14 is not limited to four. In particular, the number of first multicore fibers 15 installed in the reference connector ferrule 14 may be the same as the number of second multicore fibers 17 installed in the ferrule member 10.

[0024] Fig. 6 is a perspective view showing the state in which the ferrule member and the reference connector ferrule are connected. As shown in Fig. 6, guide pins 13 are inserted into guide pin holes 12 of the ferrule member 10, and the reference connector ferrule 14 is connected so as to be in close contact with the ferrule member 10. At this time, the guide pins 13 are inserted into the guide pin holes 12 of the reference connector ferrule 14. Note that the connection between the ferrule member 10 and the reference connector ferrule 14 may be made using a method that uses the guide pin holes 12 and the guide pins 13, or may be made using a method other than the method described here.

[0025] By connecting the ferrule member 10 and the reference connector ferrule 14, the end face of the second multicore fiber 17 provided in the ferrule member 10 and the end face of the first multicore fiber 15 provided in the reference connector ferrule 14 come into close contact. Here, it is necessary to rotate and align the second multicore fiber 17 so that the arrangement of the cores 20 of the second multicore fiber 17 matches the arrangement of the cores 16 of the first multicore fiber 15. Furthermore, when inserting the guide pins 13 into the two guide pin holes 12 of the ferrule member 10 and connecting the reference connector ferrule 14 to the ferrule member 10, spacers of a desired thickness may be sandwiched between the ferrule end faces on the outside of each guide pin. By sandwiching the spacer, it is possible to fix the second multicore fiber 17 in a shape that protrudes from the end face of the ferrule member 10. By configuring the second multicore fiber 17 to protrude from the end face of the ferrule member 10, it is possible to manufacture a multi-core optical fiber connector in which the fiber end faces are reliably in close contact with each other.

[0026] [Method of Manufacturing a Multi-Fiber Optical Fiber Connector] FIG. 7 is a flowchart showing an example of a method of manufacturing a multi-fiber optical fiber connector according to the present disclosure.

[0027] In step S101, the ferrule member 10 and the reference connector ferrule 14 are connected.

[0028] In step S103, a light source is connected to one core 16 of the first multicore fiber 15, which is connected to the second multicore fiber 17 to be aligned. When connecting the light source, a fan-in (not shown) may be used. The fan-in may be a system that connects the first multicore fiber 15 and a single-core optical fiber using a spatial optical system, or may be a fiber bundle type system. Alternatively, the first multicore fiber 15 to which the light source is connected may have multiple cores 16.

[0029] In step S105, a photoreceiver is connected to one core 20 of the second multicore fiber 17 to be aligned. When connecting the photoreceiver, a fan-out (not shown) may be used. The fan-out may be a type that connects the second multicore fiber 17 and a single-core optical fiber using a spatial optical system, or may be a bundle fiber type. Alternatively, the second multicore fiber 17 to which the photoreceiver is connected may have multiple cores 20.

[0030] In step S107, the second multi-core fiber 17 to be aligned is sucked through the suction hole 21 provided in the groove 11 in which the second multi-core fiber 17 is placed.

[0031] For example, it is possible to attach a suction tube or the like (not shown) from the bottom surface of the ferrule member 10 to the suction hole 21 of the groove 11, and connect a rotary pump to the tube to perform suction. The suction method is not limited to these methods as long as it can suck the second multi-core fiber 17 placed in the groove 11.

[0032] The suction holes 21 may be arranged in various ways in the grooves 11. As shown in Figure 1, one suction hole 21 may be provided near the center of the valley of each groove in the longitudinal direction.

[0033] 8 is a top view showing an example of the arrangement of suction holes in a ferrule member. As shown in FIG. 8, the suction holes 21 may be arranged offset in the longitudinal direction of the valleys of each groove. By offsetting the suction holes 21 in the longitudinal direction of the valleys 27 of the grooves, it is possible to suck only the desired groove and prevent the adjacent grooves from being sucked.

[0034] 9 is a top view showing a modified example of the arrangement of suction holes in the ferrule member. As shown in FIG. 9, multiple short holes may be provided in the valleys of the grooves. By shortening the length of each hole, it is possible to prevent the optical fiber being sucked from bending even when a strong suction force is applied.

[0035] In step S109, the second multicore fiber 17 to be aligned is placed in a predetermined groove 11. Here, the second multicore fiber 17 is in a sucked state and is not completely fixed to the ferrule member 10. The second multicore fiber 17 is placed in the groove 11 in a state in which it is rotatable around the axis of the second multicore fiber 17. By sucking the second multicore fiber 17 through the suction hole 21, it is possible to prevent the second multicore fiber 17 from floating from the groove 11, and it is possible to stably adjust the core position by rotation for each second multicore fiber 17.

[0036] In step S111, the optical power obtained by the photodetector is acquired while rotating the second multi-core fiber 17 to be aligned. Then, the second multi-core fiber 17 is aligned based on the optical power.

[0037] Here, the light acquired by the photodetector is light that arrives from the light source via the first multicore fiber 15 and the second multicore fiber 17. By rotating the second multicore fiber 17, there exists a position of the second multicore fiber 17 where the arrangement of the cores 16 of the first multicore fiber 15 coincides with the arrangement of the cores 20 of the second multicore fiber 17. By positioning the second multicore fiber 17 in such a positional relationship, it becomes possible to reduce connection loss when fabricating the connector.

[0038] For example, when the power of light acquired by the photoreceiver becomes equal to or greater than a predetermined threshold, it may be determined that the arrangement of the cores 16 of the first multicore fiber 15 and the arrangement of the cores 20 of the second multicore fiber 17 match, and the second multicore fiber 17 may be positioned. Alternatively, when the power of light acquired by the photoreceiver becomes maximum with respect to the rotation angle of the second multicore fiber 17, it may be determined that the arrangement of the cores 16 of the first multicore fiber 15 and the arrangement of the cores 20 of the second multicore fiber 17 match, and the second multicore fiber 17 may be positioned.

[0039] Alternatively, the second multi-core fiber 17 may be rotated manually or by using, for example, a motor, etc. A mechanism may be provided that cooperates with a photodetector to stop the rotation of the motor when the optical power is at a maximum, thereby stopping the rotation of the second multi-core fiber 17.

[0040] In step S113, it is determined whether or not there is an unaligned second multi-core fiber 17. If there is an unaligned second multi-core fiber 17 (YES in step S113), the process returns to step S103.

[0041] On the other hand, if there is no unaligned second multi-core fiber 17 (NO in step S113), the second multi-core fiber 17 is fixed in step S115.

[0042] For example, the second multicore fiber 17 may be bonded and fixed to the ferrule member 10 by using a two-component thermosetting adhesive based on epoxy resin and heating the ferrule with the adhesive applied. Resins other than epoxy may also be used for bonding and fixing. Also, adhesives other than two-component, i.e., one-component adhesives may also be used.

[0043] Furthermore, it is also possible to use a curing adhesive other than a thermosetting adhesive. For example, it is also possible to use an ultraviolet curing adhesive. In this case, the second multi-core fiber 17 may be adhered and fixed to the ferrule member 10 by irradiating the adhesive with ultraviolet light. The adhesive is not limited to the examples given here as long as it can adhere and fix the second multi-core fiber 17 to the ferrule member 10.

[0044] When adhesively fixing the second multi-core fiber 17 to the ferrule member 10, an adhesive may be applied in advance to a portion of the groove 11 other than the suction holes, and then the second multi-core fiber 17 may be placed thereon. By applying adhesive in advance to the groove 11 located below the second multi-core fiber 17, the second multi-core fiber 17 can be adhesively fixed evenly at the top and bottom.

[0045] Then, in step S117, the fiber holding member 22 is fixed to the ferrule member 10. The ferrule fabricated by adhesively fixing the fiber holding member 22 to the ferrule member 10 is rotated up and down, and adhesive is applied through the suction holes 21, so that the second multi-core fiber 17 can be adhesively fixed to the ferrule member 10 more stably.

[0046] Additionally, the fabricated multi-fiber optical connector may be polished at the ferrule end faces, which makes it possible to reduce reflected light when optical communication transmission is performed with the fiber end faces connected by physical contact.

[0047] Furthermore, although the light source 18 is connected to one core 16 of the first multicore fiber 15 of the reference connector ferrule 14 and the photodetector 19 is connected to one core 20 of the second multicore fiber 17 arranged in the groove 11 of the ferrule member 10, in a state in which the photodetector 19 is connected to one core 16 of the first multicore fiber 15 of the reference connector ferrule 14 and the light source 18 is connected to one core 20 of the second multicore fiber 17 arranged in the groove 11 of the ferrule member 10, it may be determined that the arrangement of the cores 16 of the first multicore fiber 15 and the arrangement of the cores 20 of the second multicore fiber 17 match based on the power of light obtained by the photodetector, and the second multicore fiber 17 may be positioned.

[0048] [Effects of the Embodiments] As described above in detail, according to the method for manufacturing a multi-core optical fiber connector and the multi-core optical fiber connector according to the present disclosure, a reference connector ferrule and a ferrule member are connected, a light source is connected to one core included in a first multi-core fiber fixed to the reference connector ferrule, and a photoreceiver is connected to one core included in a second multi-core fiber installed in the ferrule member. The second multi-core fiber is sucked through a suction hole provided in a groove of the ferrule member, and the second multi-core fiber is placed in the groove in a state where it is rotatable around its axis. The power of light arriving from the light source via the first multi-core fiber and the second multi-core fiber is obtained by the photoreceiver, and the second multi-core fiber is positioned around its axis with respect to the groove based on the power.

[0049] This makes it possible to align the multi-core fiber without relying on the image accuracy of image observation, and to achieve low-loss connection. In particular, since the multi-core fiber can be aligned without observing the end face of the multi-core fiber with a microscope, work efficiency is improved. Furthermore, it is possible to easily mass-produce and provide multi-core optical fiber connectors that can be connected with low loss.

[0050] In addition, in the method for manufacturing a multi-core optical fiber connector and the multi-core optical fiber connector according to the present disclosure, the power may be maximized when the second multi-core fiber is positioned relative to the groove around its axis, thereby making it possible to more reliably reduce connection loss during connector manufacturing.

[0051] 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.

[0052] 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.

[0053] 10 Ferrule member 11 Groove 12 Guide pin hole 13 Guide pin 14 Reference connector ferrule 15 First multi-core fiber 16, 20 Core 17 Second multi-core fiber 21 Suction hole 22 Fiber holding member CP Center

Claims

1. A method for manufacturing a multi-core optical fiber connector, comprising: connecting a reference connector ferrule and a ferrule member; connecting a light source to one core included in a first multi-core fiber fixed to the reference connector ferrule; connecting a photodetector to one core included in a second multi-core fiber installed in the ferrule member; sucking the second multi-core fiber through a suction hole provided in a groove of the ferrule member, and arranging the second multi-core fiber in the groove in a state where it can rotate freely around its axis; obtaining the power of light received from the light source via the first multi-core fiber and the second multi-core fiber with the photodetector; and positioning the second multi-core fiber around its axis with respect to the groove based on the power.

2. The method for manufacturing a multi-core optical fiber connector according to claim 1, wherein the power reaches a maximum when the second multi-core fiber is positioned relative to the groove around the axis.

3. A multi-core optical fiber connector comprising: a reference connector ferrule; a ferrule member connected to the reference connector ferrule; a first multi-core fiber fixed to the reference connector ferrule; and a second multi-core fiber installed in the ferrule member, wherein a light source is connected to one core included in the first multi-core fiber; a photodetector is connected to one core included in the second multi-core fiber; the second multi-core fiber is sucked through a suction hole provided in a groove of the ferrule member, and the second multi-core fiber is placed in the groove in a state where it can rotate freely around its axis; the power of light arriving from the light source via the first multi-core fiber and the second multi-core fiber is obtained by the photodetector; and the second multi-core fiber is positioned relative to the groove around its axis based on the power.

4. The multi-core optical fiber connector according to claim 3, wherein the power reaches a maximum when the second multi-core fiber is positioned relative to the groove around the axis.

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