Multi-fiber optical ferrule, optical connector, and method for manufacturing multi-fiber optical ferrule

Abstract

To provide a multi-fiber optical ferrule capable of improving bonding strength of a bare fiber of an optical fiber to a multi-fiber optical ferrule in a connection end face, and to provide an optical connector and a method for manufacturing the multi-fiber optical ferrule.SOLUTION: A multi-fiber optical ferrule comprises: a body having a connection end face connected to a connection object; and a plurality of insertion holes which extend from the connection end face toward an inside of the body and into which optical fibers can be inserted. Each of the plurality of insertion holes has a first inner diameter part opening at the connection end face and a second inner diameter part having a larger diameter than that of the first inner diameter part. An inner wall of the first inner diameter part has a plurality of minute holes.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a multi-fiber optical ferrule, an optical connector, and a method for manufacturing the multi-fiber optical ferrule. [Background technology]

[0002] Patent Document 1 discloses a ferrule having an insertion hole for inserting an optical fiber in its longitudinal direction. In Patent Document 1, the ferrule is formed with a main chamber for holding the coating of the optical fiber. By providing a plurality of recesses on the inner wall of the main chamber, the amount of adhesive filled in the main chamber can be increased, and the coating of the optical fiber can be firmly bonded to the main chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2022 / 0381998 Summary of the Invention [Problem to be solved by the invention]

[0004] In the structure of Patent Document 1, the coating of the optical fiber can be firmly bonded to the ferrule, but the coating of the optical fiber and the bare fiber disposed inside the coating move relative to each other. In order to reduce connection loss in connecting an optical connector to a connection target, it is required to stabilize the position of the bare fiber of the optical fiber exposed at the connection end surface of the ferrule to the connection target. Therefore, it is desired to firmly bond the bare fiber of the optical fiber to the ferrule near the connection end surface.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a multi-core optical ferrule, an optical connector, and a method for manufacturing a multi-core optical ferrule that are capable of improving the adhesive strength of the bare fibers of an optical fiber to the multi-core optical ferrule in the vicinity of the connection end face. [Means for solving the problem]

[0006] In order to solve the above problems, a multi-core optical ferrule according to a first aspect of the present invention comprises a main body having a connection end face to be connected to a connection target, and a plurality of insertion holes extending from the connection end face toward the inside of the main body and through which optical fibers can be inserted, each of the plurality of insertion holes having a first inner diameter portion opening to the connection end face and a second inner diameter portion having a larger diameter than the first inner diameter portion, and an inner wall of the first inner diameter portion has a plurality of fine holes.

[0007] A second aspect of the present invention is the multi-core optical ferrule of the first aspect, further comprising a receiving portion that communicates with the second inner diameter portion and is capable of receiving a coating of the optical fiber.

[0008] A third aspect of the present invention is the multi-core optical ferrule of the second aspect, wherein the second inner diameter portion has the plurality of fine holes.

[0009] A fourth aspect of the present invention is the multi-core optical ferrule according to any one of the first to third aspects, wherein at least some of the plurality of micropores have an opening width of 1 μm or more.

[0010] An optical connector according to aspect 5 of the present invention comprises a multi-core optical ferrule according to any one of aspects 1 to 4, a plurality of optical fibers inserted into the plurality of insertion holes, and an adhesive for adhering the plurality of optical fibers to the multi-core optical ferrule, wherein the adhesive is disposed at least between a bare fiber of the optical fiber and the first inner diameter portion.

[0011] A manufacturing method for a multi-core optical ferrule according to aspect 6 of the present invention is a manufacturing method for a multi-core optical ferrule having a main body having a connection end face and a plurality of insertion holes extending from the connection end face toward the inside of the main body, comprising the steps of: preparing a mold body that forms the outer surface of the main body; and insertion hole pins that form the insertion holes; adhering fine particles to the insertion hole pins; placing the insertion hole pins with the fine particles attached within the mold body; injecting resin into the mold body and solidifying it; and removing the fine particles remaining in the solidified resin. Effect of the Invention

[0012] According to the above aspects of the present invention, it is possible to provide a multi-core optical ferrule, an optical connector, and a method for manufacturing a multi-core optical ferrule that can improve the adhesive strength of the bare fiber of an optical fiber to the multi-core optical ferrule in the vicinity of the connection end face. [Brief description of the drawings]

[0013] [Figure 1] 1 is a perspective view of an optical connector according to an embodiment; [Diagram 2] FIG. 2 is a cross-sectional view taken along the line II-II in FIG. [Diagram 3] FIG. 3 is a perspective view of FIG. 2. [Figure 4] 4 is a flowchart showing an example of a method for manufacturing a multi-core optical ferrule according to the present embodiment. [Diagram 5] 10A to 10C are diagrams illustrating a step of adhering fine particles to an insertion hole pin in the manufacturing method of the multi-core optical ferrule according to the embodiment. [Figure 6] 4A to 4C are diagrams illustrating an injection molding step in the manufacturing method of the multi-core optical ferrule according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multi-core optical ferrule and an optical connector according to an embodiment will be described below with reference to the drawings. As shown in FIG. 1, the optical connector 1 includes a multi-core optical ferrule 10, a plurality of optical fibers 20, two guide pins 30, a boot 40, and an adhesive 50. Note that the optical connector 1 may not include the guide pins 30 and the boot 40.

[0015] The multi-core optical ferrule 10 includes a ferrule body 11 (main body). A plurality of insertion holes 12 into which the plurality of optical fibers 20 can be individually inserted are formed in the ferrule body 11. The ferrule body 11 has a connection end face 11a at which the insertion holes 12 open.

[0016] (Direction definition) In this specification, the longitudinal direction of the insertion hole 12 is referred to as the axial direction. Also, the side of the connection end face 11a in the axial direction is referred to as the front or tip side, and the opposite side is referred to as the rear or base end side.

[0017] The multi-core optical ferrule 10 has a ferrule body 11, a plurality of insertion holes 12, two guide holes 13, an introduction hole 14 (receiving portion) (see FIG. 2), and an injection hole 15.

[0018] The ferrule body 11 has a connection end face 11a which is the front end face and a rear end face 11b. The connection end face 11a is the face that abuts against a connection target when the optical connector 1 is connected to a connection target such as another connector. A plurality of openings 11a1 are formed in the connection end face 11a. The plurality of insertion holes 12 each extend from the plurality of openings 11a1 toward the inside of the ferrule body 11. The introduction hole 14 is located rearward of the insertion holes 12. The introduction hole 14 communicates with the insertion holes 12 and extends axially from the rear end of the insertion holes 12. The introduction hole 14 opens at the rear end face 11b. The optical fibers 20 are introduced into the insertion holes 12 through the introduction hole 14.

[0019] The two guide holes 13 are formed in the ferrule body 11. The two guide holes 13 open to the connection end face 11a. A guide pin 30 is inserted into each of the two guide holes 13. The injection hole 15 is formed in the upper surface of the ferrule body 11. The injection hole 15 communicates with the internal space of the ferrule body 11.

[0020] The material of the ferrule body 11 may be PEEK (polyether ether ketone), LCP (liquid crystal polymer), PEI (polyetherimide), PPS (polyphenylene sulfide), or a mixture of these. A filler such as glass fiber may be added to the above materials. The material of the ferrule body 11 may be a resin other than the above.

[0021] As shown in FIG. 2, the optical fiber 20 has a bare fiber 21 and a coating 22. The bare fiber 21 has a core 21a and a clad 21b. The clad 21b covers the core 21a. The bare fiber 21 is made of, for example, quartz glass. The bare fiber 21 may be made of resin. The clad 21b has a lower refractive index than the core 21a. Therefore, light can be confined within the core 21a. The coating 22 partially covers the bare fiber 21 and plays a role in protecting the bare fiber 21. The coating 22 is made of resin or the like. For example, the material of the coating 22 may be a UV-curable resin. At the front end of the optical fiber 20, the coating 22 is not provided and the bare fiber 21 is exposed. The bare fiber 21 is inserted into the insertion hole 12 of the multi-core optical ferrule 10. The introduction hole 14 of the multi-core optical ferrule 10 is capable of receiving the coating 22 of the optical fiber 20.

[0022] The insertion hole 12 has a small-diameter portion 12a (first inner diameter portion) and a large-diameter portion 12b (second inner diameter portion). The small-diameter portion 12a opens to the connection end face 11a. The large-diameter portion 12b is located behind the small-diameter portion 12a. The inner diameter of the large-diameter portion 12b is larger than the inner diameter of the small-diameter portion 12a. The large-diameter portion 12b has a function as a guide to facilitate the entry of the bare fiber 21 into the small-diameter portion 12a. The small-diameter portion 12a has a function of defining the position of the bare fiber 21. Inside the small-diameter portion 12a, the positions of the respective bare fibers 21 are determined, thereby achieving an optical connection between the optical connector 1 and the connection target.

[0023] The boot 40 is a cylindrical member through which a plurality of optical fibers 20 are inserted. The boot 40 is fixed to the rear end portion of the multi-core optical ferrule 10. The boot 40 has a role of protecting the optical fiber 20.

[0024] The adhesive 50 has a function of fixing the plurality of optical fibers 20 to the multi-core optical ferrule 10. As the material of the adhesive 50, for example, a thermosetting resin can be used. More specifically, the material of the adhesive 50 may be an epoxy resin. The adhesive 50 is injected into the internal space of the ferrule main body 11 through the injection hole 15. The injected adhesive 50 enters the inside of the introduction hole 14 and the inside of the insertion hole 12. That is, the adhesive 50 is disposed between the optical fiber 20 and the introduction hole 14, between the bare fiber 21 of the optical fiber 20 and the large-diameter portion 12b of the insertion hole 12, and between the bare fiber 21 of the optical fiber 20 and the small-diameter portion 12a of the insertion hole 12.

[0025] As shown in FIG. 3, a plurality of fine holes are formed in the inner wall of the insertion hole 12. The fine holes are recessed portions that are recessed from the inner wall of the insertion hole 12. The width of the opening of the fine hole is 1.0 μm or more. The width of the opening of the fine hole is preferably, for example, 1.0 to 9.0 μm. In the present embodiment, the plurality of fine holes are formed on both the inner wall of the small-diameter portion 12a and the inner wall of the large-diameter portion 12b. Note that the plurality of fine holes may be formed at least in a portion of the small-diameter portion 12a that is at a predetermined distance in the axial direction from the end on the connection end face 11a side.

[0026] Here, in order to reduce connection loss in connecting the optical connector 1 to a connection target, it is required to stabilize the position of the bare fiber 21 exposed at the connection end face 11a. Therefore, it is desired that the bare fiber 21 of the optical fiber 20 is firmly bonded to the multi-core optical ferrule 10 in the vicinity of the connection end face 11a.

[0027] In this embodiment, since a plurality of micropores are formed on the inner wall of the insertion hole 12, the adhesion area between the insertion hole 12 and the adhesive 50 can be increased. In addition, since the adhesive 50 enters the plurality of micropores, the adhesive strength between the insertion hole 12 and the adhesive 50 increases due to an anchor effect. Therefore, the adhesive 50 can firmly adhere the bare fiber 21 of the optical fiber 20 to the multi-core optical ferrule 10 (insertion hole 12). In particular, since the plurality of micropores are formed on the inner wall of the small diameter portion 12a that opens to the connection end face 11a, the bare fiber 21 can be firmly adhered to the multi-core optical ferrule 10 in the vicinity of the connection end face 11a.

[0028] An example of a method for manufacturing the multi-core optical ferrule 10 will be described below. In this embodiment, the multi-core optical ferrule 10 is formed by injection molding. Fig. 4 is a flowchart showing an example of a method for manufacturing the multi-core optical ferrule 10 according to this embodiment.

[0029] First, a mold for injection molding is prepared (step S1). The mold has a mold body that forms the outer surface of the ferrule body 11 and molding pins that form each hole of the multi-core optical ferrule 10. The molding pins include insertion hole pins P that form the insertion holes 12.

[0030] Next, as shown in FIG. 5, a volatile solvent containing fine particles is sprayed onto the pins P for insertion holes, thereby adhering the fine particles to the pins P for insertion holes (step S2). The material of the fine particles is, for example, carbon such as graphite, or ceramics such as boron nitride. The particle diameter of the fine particles is, for example, preferably 1.0 to 9.0 μm. The median diameter of the fine particles is, for example, preferably 3.0 to 3.5 μm. As a specific example, good results were obtained when fine particles of graphite having an average diameter of 3.0 μm were used. Although the surface roughness (arithmetic mean roughness Ra) of the pins P for insertion holes was 0.02 to 0.03 μm, by adhering the fine particles of graphite to the pins P for insertion holes, micropores corresponding to the shape of the fine particles were formed on the inner wall of the insertion hole 12. Also, good results were obtained when fine particles of boron nitride having an average diameter of 8.5 μm were used.

[0031] Next, the molding pins including the through-hole pins P to which the fine particles are attached are placed in the cavity of the mold body (step S3).

[0032] Then, injection molding is performed (step S4). Specifically, molten high-temperature resin is injected into the cavity of the mold body, and the resin is cooled and solidified. The solidified resin is removed from the mold. Since the fine particles are attached to the insertion hole pin P, the insertion hole pin P can be easily pulled out from the solidified resin. As shown in Fig. 6, the insertion hole pin P forms an insertion hole 12 in the ferrule body 11. The shape of the particles attached to the insertion hole pin P is transferred to the inner wall of the insertion hole 12, thereby forming a plurality of micropores in the inner wall of the insertion hole 12. The size of the micropores can be adjusted by adjusting the particle size of the particles attached to the insertion hole pin P. The position where the micropores are formed in the insertion hole 12 can be adjusted by adjusting the position where the particles are attached on the insertion hole pin P.

[0033] Thereafter, any particles remaining on the inner wall of the insertion hole 12 are removed by cleaning (step S5), thereby completing the manufacture of the multi-core optical ferrule 10.

[0034] As described above, the multi-core optical ferrule 10 of this embodiment comprises a ferrule body 11 having a connection end face 11a to be connected to a connection target, and a plurality of insertion holes 12 extending from the connection end face 11a toward the inside of the ferrule body 11 and through which optical fibers 20 can be inserted, each of the plurality of insertion holes 12 having a small diameter portion 12a opening at the connection end face 11a and an enlarged diameter portion 12b having a diameter larger than that of the small diameter portion 12a, and the inner wall of the small diameter portion 12a has a plurality of fine holes. In addition, the optical connector 1 of this embodiment includes a multi-core optical ferrule 10, a plurality of optical fibers 20 inserted into a plurality of insertion holes 12, and an adhesive 50 that adheres the plurality of optical fibers 20 to the multi-core optical ferrule 10, and the adhesive 50 is disposed at least between the bare fiber 21 of the optical fiber 20 and the small diameter portion 12a. According to this configuration, multiple fine holes are formed in the inner wall of the small diameter portion 12a that opens to the connection end face 11a, thereby improving the adhesive strength of the bare fiber 21 of the optical fiber 20 to the multi-core optical ferrule 10 in the vicinity of the connection end face 11a.

[0035] The multi-core optical ferrule 10 also has an introduction hole 14 that communicates with the enlarged diameter portion 12 b and is capable of receiving the coating 22 of the optical fiber 20 .

[0036] In addition, the enlarged diameter portion 12b has a plurality of fine holes, which allows the bare fibers 21 of the optical fiber 20 to be bonded to the multi-core optical ferrule 10 more firmly.

[0037] Furthermore, at least some of the micropores have a dimension of 1 μm or more, which allows the bare fiber 21 of the optical fiber 20 to be bonded to the multi-core optical ferrule 10 more firmly.

[0038] Furthermore, the manufacturing method for the multi-core optical ferrule 10 according to this embodiment involves preparing a mold body which forms the outer surface of the ferrule body 11 and insertion hole pins P which form the insertion holes 12, adhering fine particles to the insertion hole pins P, placing the insertion hole pins P with the fine particles attached within the mold body, injecting resin into the mold body and solidifying it, and removing any fine particles remaining in the solidified resin.

[0039] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0040] For example, in the manufacturing method of the multi-core optical ferrule 10 in the above embodiment, a mold release agent may be applied to the mold before step S4 in order to make it easier to remove the resin solidified in step S4 from the mold. Also, in order to remove internal stress of the multi-core optical ferrule 10, a heat treatment may be performed on the multi-core optical ferrule 10 after step S5.

[0041] In addition, for example, optical connectors may be applied to a CPO (Co-Packaged Optics) structure in which an optical fiber is brought into contact with an optical integrated circuit mounted on an electronic board for direct connection. In this case, when the electronic components of the optical integrated circuit are reflowed, the optical connector is heated together, which may cause part of the adhesive that bonds the optical fiber to the ferrule to peel off, resulting in axial retraction (pistoning) of the optical fiber. As described above, in this embodiment, since a plurality of micropores are formed in the inner wall of the insertion hole 12, the adhesion area between the insertion hole 12 and the adhesive 50 can be increased, and the anchor effect increases the adhesive strength between the insertion hole 12 and the adhesive 50. Therefore, even when the optical connector 1 is applied to a CPO structure, peeling of the adhesive 50 due to reflow of electronic components of the optical integrated circuit can be suppressed, and the occurrence of axial recession (pistoning) of the optical fiber 20 can be suppressed.

[0042] In addition, within the scope of the spirit of the present invention, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate. [Explanation of symbols]

[0043] REFERENCE SIGNS LIST 1...optical connector 10...multi-core optical ferrule 11...ferrule body (body) 11a...connection end face 12...insertion hole 12a...small diameter portion (first inner diameter portion) 12b...expanded diameter portion (second inner diameter portion) 14...introduction hole (receiving portion) 20...optical fiber 21...bare fiber 22...coating 50...adhesive

Claims

1. A main body having a connection end surface to be connected to a connection object; a plurality of insertion holes extending from the connection end surface toward the inside of the main body and through which optical fibers can be inserted; Each of the plurality of insertion holes has a first inner diameter portion that opens into the connection end surface and a second inner diameter portion that has a larger diameter than the first inner diameter portion, The inner wall of the first inner diameter portion has a plurality of micropores. Multi-core optical ferrule.

2. 2. The multi-core optical ferrule according to claim 1, further comprising a receiving portion communicating with said second inner diameter portion and capable of receiving a coating of said optical fiber.

3. The multi-core optical ferrule according to claim 2 , wherein the second inner diameter portion has the plurality of fine holes.

4. 4. The multi-core optical ferrule according to claim 1, wherein at least some of the plurality of micropores have an opening width of 1 μm or more.

5. A multi-core optical ferrule according to any one of claims 1 to 3, A plurality of optical fibers inserted into the plurality of insertion holes; an adhesive for bonding the plurality of optical fibers to the multi-core optical ferrule; The adhesive is disposed at least between a bare fiber of the optical fiber and the first inner diameter portion.

6. A method for manufacturing a multi-core optical ferrule including a body having a connection end face and a plurality of insertion holes extending from the connection end face toward an inside of the body, the method comprising the steps of: preparing a mold body for forming an outer surface of the body and an insertion hole pin for forming the insertion hole; Adhering fine particles to the insertion hole pin; The insertion hole pin to which the fine particles are attached is placed in the mold body; Injecting a resin into the mold body and solidifying it; removing the fine particles remaining in the solidified resin; A method for manufacturing a multi-core optical ferrule.

Images