Ferrule, optical connector, and method for manufacturing ferrule

Abstract

To provide a ferrule capable of preventing deterioration of optical characteristics, an optical connector, and a method for manufacturing such a ferrule.SOLUTION: The ferrule includes a front end surface, a rear end surface located on a side opposite to the front end surface in a first direction, and fiber holes that open in the front end surface and into which end portions of a plurality of optical fibers arranged in a second direction intersecting the first direction can be inserted. The fiber hole includes a plurality of first hole portions each extending along the first direction and into which an end portion of a corresponding optical fiber of the plurality of optical fibers can be inserted, and a plurality of connection portions each connecting adjacent first hole portions of the plurality of first hole portions.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] An optical connector is known that includes a plurality of optical fibers and a ferrule that holds the ends of the plurality of optical fibers (see, for example, Patent Document 1). The ferrule has a plurality of holes formed in a row in a predetermined direction, and the plurality of optical fibers are inserted into the corresponding holes. Such a ferrule is manufactured by placing a plurality of core pins, each having a shape corresponding to the holes, in a mold and filling the mold with ferrule material (for example, molten resin). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-119622 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, optical fibers (thin-diameter fibers) with coating diameters smaller than those of conventional optical fibers have been developed. Compared to conventional optical fibers, thin-diameter fibers have thinner coating layers, allowing for optical fibers to be arranged at a narrower pitch. However, as the pitch of optical fibers becomes narrower, the pitch of holes formed in ferrules and the pitch of core pins used to form the holes during ferrule manufacturing also become narrower. This can lead to the risk that the ferrule material filled into the mold during ferrule manufacturing may not be properly filled between the core pins, resulting in holes for inserting optical fibers not being formed in the desired position and shape. This can increase loss when connecting an optical connector to a mating optical connector, potentially resulting in degraded optical characteristics.

[0005] An object of the present disclosure is to provide a ferrule, an optical connector, and a method for manufacturing such a ferrule that can prevent degradation of optical properties. [Means for solving the problem]

[0006] A ferrule according to an embodiment of the present disclosure includes a front end face, a rear end face located on the opposite side of the front end face in a first direction, and fiber holes that open at the front end face and into which ends of a plurality of optical fibers aligned in a second direction intersecting the first direction can be inserted. Each of the fiber holes extends along the first direction and has a plurality of first hole portions into which ends of corresponding optical fibers among the plurality of optical fibers can be inserted, and a plurality of connection portions that respectively connect adjacent first hole portions among the plurality of first hole portions. [Effects of the Invention]

[0007] According to the present disclosure, a ferrule, an optical connector, and a method for manufacturing such a ferrule are provided that can prevent degradation of optical properties. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an optical connector according to a first embodiment. [Figure 2] FIG. 2 is a plan view of the optical connector shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view of the optical fiber shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the ferrule taken along line IV-IV shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view of the ferrule taken along line VV shown in FIG. [Figure 6] FIG. 6 is a view showing the front end face of the ferrule shown in FIG. [Figure 7] FIG. 7 is a perspective view showing a part of a structure used in manufacturing the ferrule according to the first embodiment. [Figure 8]FIG. 8 is a view showing the front end face of the ferrule according to the second embodiment. [Figure 9] FIG. 9 is a perspective view showing a part of a structure used in manufacturing a ferrule according to the second embodiment. [Figure 10] FIG. 10 is a plan view showing a part of a structure used in manufacturing a ferrule according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] First, the contents of the embodiments of the present disclosure will be listed and described. (1) The ferrule of the present disclosure comprises a front end face, a rear end face located on the opposite side of the front end face in a first direction, and fiber holes that open at the front end face and into which ends of a plurality of optical fibers aligned in a second direction that intersects the first direction can be inserted, each of the fiber holes extending along the first direction and having a plurality of first hole portions into which ends of corresponding optical fibers among the plurality of optical fibers can be inserted, and a plurality of connection portions that respectively connect adjacent first hole portions among the plurality of first hole portions.

[0010] In this ferrule, the fiber holes each extend along a first direction and include a plurality of first hole portions into which ends of corresponding optical fibers from among the plurality of optical fibers can be inserted, and a plurality of connecting portions that respectively connect adjacent first hole portions from among the plurality of first hole portions. In other words, in this ferrule, because connecting portions are formed between the first hole portions, the amount of ferrule material that needs to be filled between the first hole portions (core pins for forming the first hole portions) during the ferrule manufacturing process is reduced compared to a configuration in which connecting portions are not formed. This reduces the possibility of unintended regions between the first hole portions that are not filled with ferrule material, and allows fiber holes to be formed in desired positions and shapes. Therefore, this ferrule can prevent degradation of optical characteristics.

[0011] (2) In the ferrule of (1) above, the pitch of the multiple first holes in the second direction may be 150 μm or more and 180 μm or less. In this case, even if the pitch of the first holes is narrowed due to the use of an optical fiber with a small diameter (thin-diameter fiber), it is possible to reduce the possibility of unintended regions of the ferrule material being unfilled between the first holes, and to prevent degradation of optical properties.

[0012] (3) In the ferrule of (1) or (2) above, when viewed from the first direction, the inner surface of each of the plurality of first hole portions may extend along a circle centered on an axis along the first direction. In this case, it is possible to prevent displacement of the end of the optical fiber in the first hole portion.

[0013] (4) In the ferrule of (3) above, the positions of the multiple connection portions may coincide with the centers of the multiple first holes in a third direction intersecting the first and second directions. If the inner surfaces of the first holes are circular when viewed from the first direction, the spacing between adjacent first holes is narrowest at a height (position in the third direction) that coincides with the centers of the first holes. The narrower the spacing between the first holes, the more likely it is that an unintended region will be left unfilled with ferrule material. However, in this ferrule, the positions of the connection portions coincide with the centers of the first holes in the third direction (because the connection portions are formed at the locations where the spacing between the first holes is narrowest), further reducing the likelihood of an unfilled region occurring. This further reduces the degradation of optical properties.

[0014] (5) In the ferrule of (3) or (4) above, the fiber hole may be located closer to the rear end face than the plurality of first hole portions in the first direction, and may further include a plurality of second hole portions into each of which an end of a corresponding optical fiber among the plurality of optical fibers can be inserted, and when viewed from the first direction, the inner surface of each of the plurality of second hole portions may extend along a circle centered on an axis along the first direction, and the inner diameter of each of the plurality of second hole portions may be larger than the inner diameter of each of the plurality of first hole portions. In this case, the end of the optical fiber can be easily inserted into the corresponding first hole portion via the second hole portion.

[0015] (6) In the ferrule of (1) or (2) above, the inner surface of the fiber hole may have a first surface and a second surface facing each other in a third direction intersecting the first and second directions, the first surface may have a plurality of grooves aligned in the second direction and extending along the first direction, the plurality of first hole portions may be a plurality of spaces formed between the inner surfaces of the plurality of grooves and the second surface, and the plurality of connection portions may be a plurality of spaces formed between a plurality of regions of the first surface located between the plurality of grooves and the second surface. In this case, it is possible to prevent misalignment of the end of the optical fiber in the first hole portion.

[0016] (7) In the ferrule of (6) above, when viewed from the first direction, the inner surfaces of each of the plurality of grooves may extend in a V-shape. In this case, it is possible to prevent the end of the optical fiber from being displaced in the fiber hole.

[0017] (8) In the ferrule of (6) above, when viewed from the first direction, the inner surfaces of each of the plurality of grooves may extend in a U-shape. In this case, it is possible to prevent the end of the optical fiber from being displaced in the fiber hole.

[0018] (9) An optical connector according to the present disclosure includes a plurality of optical fibers and a ferrule that holds the ends of the plurality of optical fibers. The ferrule has a front end face, a rear end face located opposite the front end face in a first direction, and fiber holes that open in the front end face. The fiber holes each have a plurality of first hole portions that extend along the first direction and a plurality of connection portions that respectively connect adjacent first hole portions among the plurality of first hole portions. The ends of the plurality of optical fibers are inserted into corresponding first hole portions among the plurality of first hole portions. For the same reasons as those described above, this optical connector allows the fiber holes to be formed in desired positions and shapes. Therefore, this optical connector can prevent degradation of optical characteristics.

[0019] (10) In the optical connector of (9) above, the outer diameter of each of the plurality of optical fibers may be 150 μm or more and 180 μm or less. In this case, since optical fibers having a smaller outer diameter (coating diameter) than general optical fibers are used, the arrangement space of the optical fibers in the ferrule can be reduced, and the ferrule can be made more compact. In addition, the number of optical fibers inserted into the ferrule can be increased, and optical characteristics can be improved.

[0020] (11) The method for manufacturing a ferrule according to the present disclosure includes the steps of: preparing a ferrule mold; arranging in the mold a structure having a plurality of pins arranged in a predetermined direction and a plurality of pin connection portions that connect adjacent core pins among the plurality of core pins; and filling the mold with ferrule material to form the ferrule.

[0021] In this ferrule manufacturing method, the structure placed in the ferrule mold has multiple pins aligned in a predetermined direction and multiple pin connection portions that connect adjacent core pins among the multiple core pins. This reduces the amount of ferrule material that needs to be filled between the core pins compared to a configuration without connection portions. This reduces the possibility of unintended regions of the ferrule material being formed between the holes (holes formed by the core pins) into which the ends of the optical fibers are inserted. Therefore, this ferrule manufacturing method prevents degradation of the optical properties of the ferrule.

[0022] (12) In the ferrule manufacturing method described in (11) above, the structure may have a main body portion, and the multiple core pins may extend so as to protrude from the main body portion. Each of the multiple core pins may include a large-diameter portion and a small-diameter portion located farther from the main body portion than the large-diameter portion and having an outer diameter smaller than the outer diameter of the large-diameter portion. The multiple pin connecting portions may connect the small-diameter portions of adjacent core pins. For example, when filling a ferrule material (e.g., molten resin) in a mold from the main body portion toward the tip of the core pin, it is difficult for the ferrule material to fill between the small-diameter portions farther from the main body portion, and there is a high possibility that an unintended unfilled area of ​​the ferrule material will occur between the small-diameter portions. In the ferrule manufacturing method described above, the multiple pin connecting portions connect the small-diameter portions of adjacent core pins, thereby further reducing the possibility of such an unfilled area occurring. This further prevents deterioration of the optical properties of the ferrule.

[0023] [Details of the embodiments of the present disclosure] Specific examples of ferrules, optical connectors, and ferrule manufacturing methods according to embodiments of the present disclosure will be described below with reference to the drawings. In the following description, identical elements or elements having identical functions will be designated by the same reference numerals, and duplicated descriptions will be omitted. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0024] [Optical connector configuration] The configuration of an optical connector 1 according to a first embodiment will be described with reference to Figs. 1 to 6. Fig. 1 is a perspective view showing an optical connector according to the first embodiment. Fig. 2 is a plan view of the optical connector shown in Fig. 1. Fig. 3 is a cross-sectional view of the optical fiber shown in Fig. 1. Fig. 3 shows cross-sections of some (three) optical fibers among a plurality of optical fibers provided in the optical connector. Fig. 4 is a cross-sectional view of the ferrule taken along line IV-IV shown in Fig. 1. Fig. 5 is a cross-sectional view of the ferrule taken along line VV shown in Fig. 1. Fig. 6 is a view showing the front end face of the ferrule shown in Fig. 1.

[0025] The optical connector 1 is optically connected to an external mating optical connector. In the following description, the connection direction of the optical connector 1 is referred to as the X-axis direction (first direction), a direction perpendicular to the X-axis direction is referred to as the Y-axis direction (second direction), and a direction perpendicular to the X-axis and Y-axis directions is referred to as the Z-axis direction (third direction). The optical connector 1 includes a plurality of optical fibers 2 and a ferrule 3.

[0026] The multiple optical fibers 2 transmit input light (optical signals). In this example, the number of the multiple optical fibers 2 is 12. An end 2a of each optical fiber 2 extends along the X-axis direction. Each optical fiber 2 has a glass fiber 21 and a coating layer 22. As shown in FIG. 3, the glass fiber 21 includes a core 23 and a clad 24 surrounding the core 23. The clad 24 has a refractive index different from that of the core 23. The refractive index of the core 23 is higher than the refractive index of the clad 24. As a result, the light input to the optical fiber 2 is guided in the core 23. The optical fiber 2 and the glass fiber 21 have a circular cross section.

[0027] The coating layer 22 is formed in a cylindrical shape and covers the outer periphery of the glass fiber 21. A portion of the tip of the coating layer 22 is removed from the optical fiber 2. That is, the end of the glass fiber 21 has an exposed portion that is not covered with the coating layer 22. The exposed portion of the glass fiber 21 is located closer to the tip surface of the optical fiber 2 than the portion of the glass fiber 21 that is covered with the coating layer 22. The coating layer 22 is formed of, for example, resin.

[0028] The ends 2a of the multiple optical fibers 2 are arranged side by side in the Y-axis direction. The coating layer 22 of each optical fiber 2 is in contact with the coating layer 22 of the adjacent optical fiber 2. The exposed portion of the glass fiber 21 of each optical fiber 2 that is not covered with the coating layer 22 is separated from the exposed portion of the glass fiber 21 of the adjacent optical fiber 2 without contacting them.

[0029] The optical fiber 2 is a small-diameter fiber with a small coating diameter. In this example, the outer diameter of the optical fiber 2 (coating layer 22) is approximately 165 μm. The outer diameter of the optical fiber 2 may be 150 μm or more and 180 μm or less. The outer diameter of the glass fiber 21 is approximately 125 μm. The thickness of the coating layer 22 is approximately 20 μm. The distance between adjacent glass fibers 21 in the Y-axis direction is approximately 40 μm. The pitch of the multiple optical fibers 2 in the Y-axis direction is approximately 165 μm. The pitch of the optical fibers 2 is the distance between the centers of adjacent optical fibers 2 when viewed from the X-axis direction.

[0030] The ferrule 3 is, for example, an MT ferrule. The ferrule 3 holds the ends 2a of multiple optical fibers 2. The ferrule 3 is formed in a substantially rectangular parallelepiped shape. In this example, the ferrule 3 is made of resin. The ferrule 3 has a front end face 3a, a rear end face 3b, a side face 3c, a side face 3d, a main face 3e, and a main face 3f. The rear end face 3b is located on the opposite side of the front end face 3a in the X-axis direction. The side face 3d is located on the opposite side of the side face 3c in the Y-axis direction. The main face 3f is located on the opposite side of the main face 3e in the Z-axis direction.

[0031] The front end face 3a is a surface that abuts against the ferrule of a mating optical connector to be connected to the optical connector 1 in the X-axis direction. The front end face 3a has a first region A1 and a second region A2 that is continuous with the first region A1. The second region A2 is located closer to the main surface 3f in the Z-axis direction than the first region A1. The first region A1 is along (parallel to) the Z-axis direction. The second region A2 is inclined with respect to the Z-axis direction so as to approach the rear end face 3b as it moves from the main surface 3e toward the main surface 3f. The inclination angle of the second region A2 with respect to the Z-axis direction may be, for example, 8 degrees.

[0032] The ferrule 3 has a fiber hole 31, a plurality of grooves 32, an internal space 33, and a pair of guide holes 34. The fiber hole 31 is a hole into which the ends 2a of a plurality of optical fibers 2 can be inserted. The fiber hole 31 has a hollow shape and opens at the front end face 3a. The fiber hole 31 includes a plurality of first hole portions 41, a plurality of connection portions 42, a plurality of tapered portions 43, and a plurality of second hole portions 44.

[0033] Each of the multiple first hole portions 41 is a hole extending along the X-axis direction. One end of each first hole portion 41 opens to the front end face 3a, and the other end is connected to the tapered portion 43. In this example, the number of the multiple first hole portions 41 matches the number of the multiple optical fibers 2 to be inserted. In this example, the number of first hole portions 41 is 12. As shown in FIG. 6 , an end portion 2a of a corresponding optical fiber 2 among the multiple optical fibers 2 can be inserted into each first hole portion 41. That is, one optical fiber 2 is inserted into one first hole portion 41. For ease of explanation, FIG. 6 illustrates only the optical fibers 2 inserted into three of the multiple first hole portions 41, and does not illustrate the optical fibers 2 inserted into the other first hole portions 41.

[0034] When viewed from the X-axis direction, the inner surface 41a of each of the multiple first hole portions 41 extends (in an arc shape) along a circle whose center is an axis along the X-axis direction. When viewed from the X-axis direction, the inner diameter of the first hole portion 41 is approximately the same as the outer diameter of the glass fiber 21. In this example, the inner diameter of the first hole portion 41 is approximately 125 μm.

[0035] The multiple first holes 41 are arranged at predetermined intervals in the Y-axis direction. The pitch P of the multiple first holes 41 in the Y-axis direction matches the pitch of the multiple optical fibers 2. The pitch P of the first holes 41 is the distance between the centers C1 of adjacent first holes 41 when viewed from the X-axis direction. In this example, the pitch P of the first holes 41 is approximately 165 μm. The pitch P of the first holes 41 may be, for example, not less than 150 μm and not more than 180 μm. The pitch P of the first holes 41 does not have to perfectly match the pitch of the optical fibers 2.

[0036] The multiple connection portions 42 connect adjacent first holes 41 among the multiple first holes 41. The multiple first holes 41 and the multiple connection portions 42 are alternately formed in the Y-axis direction. That is, one connection portion 42 is formed between a pair of adjacent first holes 41. Each connection portion 42 has a hollow shape and connects the internal spaces of adjacent first holes 41. Each connection portion 42 opens at the front end face 3a. The openings of the multiple connection portions 42 at the front end face 3a and the openings of the multiple connection portions 42 at the front end face 3a form a single opening at the front end face 3a.

[0037] The width of each connection portion 42 along the Y-axis direction is equal to the distance in the Y-axis direction between adjacent glass fibers 21. The width of each connection portion 42 along the Y-axis direction is equal to the sum of the thicknesses of the two coating layers 22 that are in contact with each other. In this example, the width of each connection portion 42 along the Y-axis direction is about 40 μm.

[0038] In the Y-axis direction, the width of each of the multiple connection portions 42 is smaller than the width of each of the multiple first holes 41. In the Z-axis direction, the width of each of the multiple connection portions 42 is smaller than the width of each of the multiple first holes 41. The width of each connection portion 42 along the Z-axis direction may be, for example, 50 μm or more. In the Z-axis direction, the position of each connection portion 42 coincides with the position of the center C1 of each first hole 41, that is, the connection portion 42 is connected to the central portion of each first hole 41 in the Z-axis direction. The connection position of each first hole 41 with the connection portion 42 may be the position where the distance to the adjacent first hole 41 is smallest (narrowest).

[0039] The multiple tapered portions 43 are holes formed between the multiple first hole portions 41 and the multiple second hole portions 44 in the X-axis direction. The multiple tapered portions 43 are aligned in the Y-axis direction. The number of the multiple tapered portions 43 matches the number of the multiple first hole portions 41. In this example, the number of tapered portions 43 is 12. One end of each tapered portion 43 is connected to the corresponding first hole portion 41, and the other end is connected to the corresponding second hole portion 44. The tapered portion 43 has a tapered shape whose diameter decreases from the rear end face 3b to the front end face 3a. In a cross section perpendicular to the X-axis direction, the tapered portion 43 has a circular shape. An end portion 2a of a corresponding optical fiber 2 among the multiple optical fibers 2 can be inserted into each tapered portion 43. In other words, one optical fiber 2 is inserted into one tapered portion 43.

[0040] The multiple second hole portions 44 are located closer to the rear end face 3b in the X-axis direction than the multiple first hole portions 41 and the multiple tapered portions 43. That is, in the direction from the front end face 3a toward the rear end face 3b, the first hole portion 41, the tapered portion 43, and the second hole portion 44 are located in this order. Each of the multiple second hole portions 44 is a hole extending along the X-axis direction. One end of each second hole portion 44 is connected to the corresponding tapered portion 43, and the other end is connected to the corresponding groove portion 32. An end portion 2a of a corresponding optical fiber 2 among the multiple optical fibers 2 can be inserted into each second hole portion 44. That is, one optical fiber 2 is inserted into one second hole portion 44.

[0041] In FIG. 6, the multiple second holes 44 are indicated by dashed lines. When viewed from the X-axis direction, the inner surface 44a of each of the multiple second holes 44 extends (in an arc shape) along a circle whose center is an axis along the X-axis direction. The inner diameter of each of the multiple second holes 44 is larger than the inner diameter of each of the multiple first holes 41. When viewed from the X-axis direction, the center of each second hole 44 coincides with the center of the corresponding first hole 41 and tapered portion 43. When viewed from the X-axis direction, the inner diameter of each second hole 44 is larger than the outer diameter of the coating layer 22 of the optical fiber 2. In this example, the inner diameter of the second hole 44 is approximately 200 μm.

[0042] The multiple second holes 44 are arranged side by side without any gaps in the Y-axis direction. That is, adjacent second holes 44 among the multiple second holes 44 are connected to each other in the Y-axis direction. More specifically, adjacent second holes 44 are directly connected in space without any intervening space (such as the connection portion 42). When viewed from the X-axis direction, the circle along the inner surface 44a of each second hole 44 contacts or overlaps with the circle along the inner surface 44a of the adjacent second hole 44. That is, the inner surface 44a of each second hole 44 is directly connected to the inner surface 44a of the adjacent second hole 44. The coating layer 22 of the optical fiber 2 inserted into a second hole 44 contacts the coating layer 22 of the optical fiber 2 inserted into the adjacent second hole 44.

[0043] The pitch of the second hole portions 44 in the Y-axis direction matches the pitch P of the first hole portions 41. The pitch of the second hole portions 44 is the distance between the centers of adjacent second hole portions 44 when viewed from the X-axis direction. In this example, the pitch of the second hole portions 44 is approximately 165 μm. The pitch of the second hole portions 44 may be, for example, not less than 150 μm and not more than 180 μm. The pitch of the second hole portions 44 does not have to perfectly match the pitch P of the first hole portions 41.

[0044] The multiple grooves 32 are formed on the inner surface of the ferrule 3 located closer to the rear end face 3b in the X-axis direction than the multiple second holes 44. Each groove 32 extends along the X-axis direction. Each groove 32 is recessed in a direction from the main surface 3e toward the main surface 3f of the ferrule 3. One end of each groove 32 is connected to the corresponding second hole 44, and the other end is connected to the internal space 33 (described later). In each groove 32, an end 2a of a corresponding optical fiber 2 among the multiple optical fibers 2 can be disposed. That is, one optical fiber 2 is disposed in one groove 32. When viewed from the X-axis direction, the inner surface 32a of each groove 32 coincides with the inner surface 44a of the corresponding second hole 44. That is, when viewed from the X-axis direction, the inner surface 32a of each groove 32 extends (in an arc shape) along a circle whose center is an axis along the X-axis direction.

[0045] The pitch of the grooves 32 in the Y-axis direction matches the pitch P of the first holes 41 and the pitch of the second holes 44. The pitch of the grooves 32 is the distance between the centers of adjacent grooves 32 when viewed from the X-axis direction. In this example, the pitch of the grooves 32 is approximately 165 μm. The pitch of the grooves 32 may be, for example, 150 μm or more and 180 μm or less. The pitch of the grooves 32 does not have to completely match the pitch P of the first holes 41 and the pitch of the second holes 44.

[0046] The internal space 33 is a storage section capable of storing multiple optical fibers 2. The internal space 33 opens to the rear end face 3b and is spatially connected to the fiber holes 31. The internal space 33 is spatially connected to the outside of the ferrule 3 via a window portion 35 that opens to the main surface 3e of the ferrule 3. The internal space 33 stores a portion of the optical fiber 2 that is covered with the coating layer 22. When viewed from the X-axis direction, the width of the internal space 33 along the Y-axis direction is larger than the width of the fiber holes 31 along the Y-axis direction, and the width of the internal space 33 along the Z-axis direction is larger than the width of the fiber holes 31 along the Z-axis direction.

[0047] Ends 2a of the multiple optical fibers 2 are accommodated in the internal space 33 through openings in the rear end face 3b. The end 2a of each optical fiber 2 accommodated in the internal space 33 is placed in the corresponding groove 32 and then inserted into the second hole 44, tapered portion 43, and first hole 41 in that order. The tip end face of the optical fiber 2 inserted into the first hole 41 is exposed to the outside of the ferrule 3 through the opening of the first hole 41 in the front end face 3a.

[0048] The ferrule 3 is disposed in the internal space 33 and further includes an adhesive (not shown) for fixing the plurality of optical fibers 2 to the ferrule 3. The adhesive may be injected into the internal space 33 through the window 35. The adhesive may be disposed so as to reach the groove 32 and the fiber hole 31.

[0049] The pair of guide holes 34 are positioned so as to sandwich the fiber hole 31 in the Y-axis direction. Each guide hole 34 extends in the X-axis direction and opens to the front end face 3a and the rear end face 3b. A guide pin (not shown) for aligning the optical connector 1 with the mating optical connector is inserted into each guide hole 34. One end of the guide pin is inserted into each guide hole 34 from an opening formed in the front end face 3a. The other end of the guide pin is inserted into a guide hole formed in the mating optical connector. The guide holes 34 and the guide pins inserted into the guide holes 34 function as positioning parts for positioning the optical connector 1 with the mating optical connector.

[0050] [Ferrule manufacturing method] Next, a method for manufacturing the ferrule 3 according to the first embodiment will be described with reference to FIG. 7. FIG. 7 is a perspective view showing a portion of the structure 6 used in manufacturing the ferrule 3. For ease of explanation, detailed configuration of the structure 6 is omitted from FIG. 7. The structure 6 is a component for forming the internal configuration of the ferrule 3 (fiber hole 31, groove 32, internal space 33, etc.), and is used by being placed in a mold for the ferrule 3 during the manufacturing process of the ferrule 3. The structure 6 is, for example, a slider. The structure 6 has a main body 61, a plurality of core pins 62 aligned in a predetermined direction (Y-axis direction), and a plurality of pin connection portions 63. The main body 61 is a portion for forming the internal space 33 of the ferrule 3. The surface of the main body 61 has a shape corresponding to the shape of the inner surface of the ferrule 3 that defines the internal space 33.

[0051] The multiple core pins 62 and the multiple pin connection portions 63 are portions for forming the fiber holes 31 and the groove portions 32. The multiple core pins 62 extend so as to protrude from the main body portion 61. The multiple core pins 62 are lined up in the Y-axis direction. Each core pin 62 extends along the X-axis direction. Each core pin 62 includes a large diameter portion 65, a tapered portion 66, and a small diameter portion 67. The tapered portion 66 and the small diameter portion 67 are located farther from the main body portion 61 (closer to the tip of the core pin 62) than the large diameter portion 65. The small diameter portion 67 is located farther from the main body portion 61 than the large diameter portion 65 and the tapered portion 66. In the direction from the main body portion 61 toward the tip of the core pin 62, the large diameter portion 65, the tapered portion 66, and the small diameter portion 67 are lined up in this order.

[0052] The large diameter portion 65 has a circular shape in a cross section perpendicular to the extension direction (X-axis direction) of the core pin 62. The outer diameter of the large diameter portion 65 matches the inner diameter of the second hole portion 44 and the groove portion 32 of the ferrule 3. The large diameter portions 65 of adjacent core pins 62 are in contact with or connected to each other. The tapered portion 66 has a circular shape in a cross section perpendicular to the extension direction of the core pin 62. The tapered portion 66 has a tapered shape in which the diameter decreases from the large diameter portion 65 toward the small diameter portion 67. The small diameter portion 67 has a circular shape in a cross section perpendicular to the extension direction of the core pin 62. The small diameter portion 67 has an outer diameter smaller than the outer diameter of the large diameter portion 65. The outer diameter of the small diameter portion 67 matches the inner diameter of the first hole portion 41 of the ferrule 3.

[0053] The multiple pin connection portions 63 connect adjacent core pins 62 among the multiple core pins 62. The multiple core pins 62 connect the thin diameter portions 67 of adjacent core pins 62. The multiple thin diameter portions 67 and the multiple pin connection portions 63 are formed alternately in the Y-axis direction. That is, one pin connection portion 63 is formed between a pair of adjacent thin diameter portions 67. Each pin connection portion 63 reaches a tip end surface 67a of the thin diameter portion 67. The tip end surface 67a is the end face of the thin diameter portion 67 in the X-axis direction and is the surface located on the opposite side from the tapered portion 66 in the X-axis direction.

[0054] In the manufacturing process of the ferrule 3, first, a mold for the ferrule 3 is prepared. The mold for the ferrule 3 has, for example, a shape corresponding to the outer shape of the ferrule 3. Next, the structure 6 is placed in the mold (the internal space of the mold). At this time, a catcher that holds the ends of the core pin 62 and the pin connecting portion 63 may be used to fix the core pin 62 and the pin connecting portion 63. Specifically, the catcher has holes formed that correspond to the shapes of the core pin 62 and the pin connecting portion 63, and the ends of the core pin 62 and the pin connecting portion 63 are inserted into the holes to fix them.

[0055] Next, the material of the ferrule 3 is filled into the mold for the ferrule 3, and the ferrule 3 is molded (injection molding is performed). Specifically, the material of the ferrule 3 (resin in this example) is melted, and the molten material is filled into the mold. The molten material of the ferrule 3 is filled into the mold so as to cover the main body 61, the core pin 62, and the pin connection portion 63. Next, the filled material is cooled and hardened. After the material has hardened, the mold and the structure 6 are removed. In this way, the ferrule 3 is formed.

[0056] When the material of the ferrule 3 is filled into the mold, the area where the main body portion 61, the core pin 62, and the pin connecting portion 63 are located is not filled with the material of the ferrule 3. Therefore, when the structure 6 is removed, the area where the main body portion 61, the core pin 62, and the pin connecting portion 63 were located is formed as a hollow area in the ferrule 3. The area where the main body portion 61 was located corresponds to the internal space 33, the area where the core pin 62 was located corresponds to the first hole portion 41, the tapered portion 43, the second hole portion 44, and the groove portion 32, and the area where the pin connecting portion 63 was located corresponds to the connecting portion 42.

[0057] In the optical connector 1 and the ferrule 3, the fiber holes 31 each extend along the X-axis direction and include a plurality of first hole portions 41 into which the ends 2a of the corresponding optical fibers 2 can be inserted, and a plurality of connecting portions 42 connecting adjacent first hole portions 41. That is, in the ferrule 3, the connecting portions 42 are formed between the first hole portions 41. This reduces the amount of ferrule 3 material that needs to be filled between the first hole portions 41 (core pins 62) during the manufacturing process of the ferrule 3 compared to a configuration in which the connecting portions 42 are not formed. This reduces the possibility of unintended unfilled regions (air traps, weld lines, etc.) of the ferrule 3 material occurring between the first hole portions 41, and allows the fiber holes 31 to be formed in the desired position and shape (improving mold transferability). Therefore, the optical connector 1 and the ferrule 3 can prevent degradation of optical characteristics.

[0058] Conventional ferrules, in which one optical fiber is inserted into each of a plurality of independent (separate) holes, are manufactured by placing a plurality of independent core pins in a ferrule mold and filling the mold with ferrule material (e.g., molten resin). The inventors have determined through resin flow analysis that the narrower the spacing between the core pins that form the holes in such conventional ferrules, the more likely it is that the material will not be properly filled between the core pins, resulting in unintended areas of the ferrule that are unfilled with material. In the ferrule 3, because the connection portion 42 is formed between the first hole portions 41, even if the spacing between the ferrule's holes is narrowed to use a small-diameter fiber, for example, unintended areas of the ferrule that are unfilled with material are unlikely to occur, preventing a deterioration in optical properties.

[0059] The pitch P of the multiple first holes 41 in the Y-axis direction may be 150 μm or more and 180 μm or less. In this case, even if the pitch P of the first holes 41 is narrowed due to the use of an optical fiber 2 with a small diameter (thin-diameter fiber), for example, it is possible to reduce the possibility that an unintended region unfilled with the material of the ferrule 3 will occur between the first holes 41, and it is possible to prevent a deterioration in optical characteristics.

[0060] When viewed from the X-axis direction, the inner surfaces 41a of the plurality of first holes 41 extend along a circle centered on an axis along the X-axis direction. This makes it possible to prevent the ends 2a of the optical fibers 2 from shifting in position within the first holes 41.

[0061] In the Z-axis direction, the positions of the multiple connection portions 42 coincide with the positions of the centers C1 of the multiple first holes 41. When the inner surface 41a of the first holes 41 is circular as viewed in the X-axis direction, the distance between adjacent first holes 41 is narrowest at a height (position in the Z-axis direction) that coincides with the position of the center C1 of the first holes 41. The narrower the distance between the first holes 41, the more likely it is that an unintended region will be left unfilled with the material of the ferrule 3. However, in the ferrule 3, the positions of the connection portions 42 coincide with the positions of the centers C1 of the first holes 41 in the Z-axis direction (because the connection portions 42 are formed at the locations where the distance between the first holes 41 is narrowest), further reducing the possibility of an unfilled region occurring. This further prevents degradation of optical characteristics.

[0062] The fiber hole 31 is located closer to the rear end face 3b in the X-axis direction than the multiple first hole portions 41, and has multiple second hole portions 44 into which the end portion 2a of the corresponding optical fiber 2 can be inserted. When viewed from the X-axis direction, the inner surface 44a of each of the multiple second hole portions 44 extends along a circle whose center is an axis along the X-axis direction, and the diameter of each of the multiple second hole portions 44 is larger than the diameter of each of the multiple first hole portions 41. This allows the end portion 2a of the optical fiber 2 to be easily inserted into the corresponding first hole portion 41 via the second hole portion 44.

[0063] The outer diameter of each of the plurality of optical fibers 2 may be 150 μm or more and 180 μm or less. In this case, since optical fibers 2 having a smaller outer diameter (coating diameter) than general optical fibers are used, the arrangement space of the optical fibers 2 in the ferrule 3 can be reduced, and the ferrule 3 can be made more compact. Furthermore, the number of optical fibers 2 inserted into the ferrule 3 can be increased, and optical characteristics can be improved. Specifically, by increasing the number of optical fibers 2, it is possible to increase the speed and capacity of communication.

[0064] In the method for manufacturing the ferrule 3, the structure 6 placed in the mold for the ferrule 3 has a plurality of core pins 62 lined up in the Y-axis direction and a plurality of pin connecting portions 63 that connect adjacent core pins 62. This reduces the amount of material of the ferrule 3 that needs to be filled between the core pins 62 compared to a configuration in which the pin connecting portions 63 are not formed. This reduces the possibility of unintended regions of the ferrule 3 that are not filled with the material of the ferrule 3 occurring between the first hole portions 41 into which the ends 2a of the optical fibers 2 are inserted. Therefore, this method for manufacturing the ferrule 3 makes it possible to prevent degradation of the optical properties of the ferrule 3.

[0065] Furthermore, because the structure 6 has the pin connecting portions 63 that connect the core pins 62, the strength of the core pins 62 can be improved compared to conventional configurations in which the core pins 62 are independent of each other. This makes it possible to prevent deformation of the core pins 62 and the fiber holes 31 formed by the core pins 62. The improved strength of the core pins 62 allows injection molding to be performed under higher pressure conditions in the manufacturing process of the ferrule 3. The improved strength of the core pins 62 increases the number of times the core pins 62 can be used, and the manufacturing cost of the ferrules 3 can be reduced.

[0066] The structure 6 has a main body 61, and multiple core pins 62 extend so as to protrude from the main body 61. Each of the multiple core pins 62 includes a large-diameter portion 65 and a small-diameter portion 67 that is located farther from the main body 61 than the large-diameter portion 65 and has an outer diameter smaller than that of the large-diameter portion 65. The multiple pin connecting portions 63 connect the small-diameter portions 67 of adjacent core pins 62 to each other. For example, when filling a mold for the ferrule 3 with material for the ferrule 3 (e.g., molten resin) in a direction from the main body 61 toward the tip of the core pin 62, it is difficult for the material for the ferrule 3 to fill between the small-diameter portions 67 that are far from the main body 61, and there is a high possibility that an unintended region where the material of the ferrule 3 is not filled between the small-diameter portions 67 is generated. In the method for manufacturing the ferrule 3, the multiple pin connecting portions 63 connect the small-diameter portions 67 of adjacent core pins 62 to each other, thereby further reducing the possibility of such an unfilled region being generated. Therefore, the optical characteristics of the ferrule 3 can be further prevented from being deteriorated.

[0067] [Second embodiment] The configuration of the optical connector 1 according to the second embodiment will be described with reference to Fig. 8. The optical connector 1 according to the second embodiment includes a ferrule 3A instead of the ferrule 3. The ferrule 3A differs from the ferrule 3 in the shape of the fiber holes.

[0068] The ferrule 3A has a fiber hole 131. An inner surface 131a of the fiber hole 131 has a first surface 51 and a second surface 52 that face each other in the Z-axis direction. In this example, the first surface 51 and the second surface 52 are aligned along the X-axis direction and the Y-axis direction. A plurality of grooves 53 are formed in the first surface 51 and aligned in the Y-axis direction. Each of the plurality of grooves 53 extends along the X-axis direction. One end of the groove 53 reaches the front end face 3a of the ferrule 3.

[0069] The grooves 53 are V-grooves. Specifically, when viewed from the X-axis direction, the inner surfaces 53a of the grooves 53 extend in a V-shape. Ends 2a of the optical fibers 2 are inserted into spaces formed between the inner surfaces 53a of the grooves 53 and the second surface 52. That is, the spaces formed between the inner surfaces 53a of the grooves 53 and the second surface 52 form first holes 141 into which the ends 2a of the optical fibers 2 corresponding to the spaces can be inserted.

[0070] A plurality of spaces formed between the second surface 52 and a plurality of regions 51a located between the plurality of grooves 53 on the first surface 51 constitute a plurality of connection portions 142 that respectively connect adjacent first holes 141. In the Y-axis direction, the plurality of first holes 141 and the plurality of connection portions 142 are alternately formed. That is, one connection portion 142 is formed between a pair of adjacent first holes 141.

[0071] Each optical fiber 2 inserted into the fiber hole 131 is in contact with the inner surface 53a and the second surface 52 of the groove portion 53. When viewed from the X-axis direction, each optical fiber 2 has two contact points B1 and B2 with the inner surface 53a, and one contact point B1 with the second surface 52. When viewed from the X-axis direction, the contact point B3 is located between the contact points B1 and B2. Each optical fiber 2 is supported by the inner surface 53a and the second surface 52 at three contact points (contact points B1, B2, B3). Because the optical fiber 2 has three contact points (contact points B1, B2, B3), the position of the optical fiber 2 in the Y-axis direction and the Z-axis direction is regulated.

[0072] When viewed from the X-axis direction, the angle between the imaginary line connecting the center C2 and contact point B1 of the optical fiber 2 and the imaginary line connecting the center C2 and contact point B2 is angle θ1. When viewed from the X-axis direction, the angle between the imaginary line connecting the center C2 and contact point B2 and the imaginary line connecting the center C2 and contact point B3 is angle θ2. When viewed from the X-axis direction, the angle between the imaginary line connecting the center C2 and contact point B3 and the imaginary line connecting the center C2 and contact point B1 is angle θ3. The angles θ1, θ2, and θ3 are all equal to one another. Each of the angles θ1, θ2, and θ3 is 120 degrees.

[0073] The end 2a of the optical fiber 2 does not contact the first surface 51. The angle of the inner surface 53a of the groove 53, the depth of the groove 53 in the Z-axis direction, and the distance in the Z-axis direction from the first surface 51 to the second surface 52 may be set so that the end 2a of the optical fiber 2 inserted into the first hole 141 does not contact the first surface 51. In this example, the distance in the Z-axis direction from the first surface 51 to the second surface 52 is approximately 80 mm.

[0074] The configuration of the structure 6A used in manufacturing the ferrule 3A will be described with reference to Figures 9 and 10. The method for manufacturing the ferrule 3A is the same as the method for manufacturing the ferrule 3, except for the shape of the structure used. Figure 9 is a perspective view showing a portion of the structure 6A used in manufacturing the ferrule 3A. Figure 10 is a plan view showing a portion of the structure 6A used in manufacturing the ferrule 3A. For ease of explanation, detailed configuration of the structure 6A is omitted in Figures 9 and 10.

[0075] The structure 6A has a main body 161, a plurality of core pins 162, and a plurality of pin connection portions 163. The configuration of the main body 161 is similar to the configuration of the main body 61 according to the first embodiment. The plurality of core pins 162 extend so as to protrude from the main body 161. The plurality of core pins 162 are aligned in the Y-axis direction. Each core pin 162 extends along the X-axis direction. Each core pin 162 includes a base end 165, a connection portion 166, and a tip end 167. The connection portion 166 and the tip end 167 are located farther from the main body 161 (closer to the tip of the core pin 162) than the base end 165. The tip end 167 is located farther from the main body 161 than the base end 165 and the connection portion 166. In the direction from the main body 161 toward the tip of the core pin 162, the base end 165, the connection portion 166, and the tip end 167 are aligned in this order.

[0076] The configuration of the base end 165 is similar to the configuration of the large diameter portion 65. The connecting portion 166 is formed so that the shape thereof in a cross section perpendicular to the X-axis direction (extension direction of the core pin 162) becomes smaller from the base end 165 toward the tip end 167. The tip end 167 has a pentagonal shape (a shape combining a rectangle and a triangle) in a cross section perpendicular to the X-axis direction. When viewed from the X-axis direction, the outer edge of the tip end 167 is located more inward than the outer edge of the corresponding base end 165. The outer shape of the tip end 167 matches the inner shape of the first hole 141 of the ferrule 3A.

[0077] The multiple pin connection portions 163 connect adjacent core pins 162 among the multiple core pins 162. The multiple core pins 162 connect tip portions 167 of adjacent core pins 162, respectively. The multiple tip portions 167 and the multiple pin connection portions 163 are formed alternately in the Y-axis direction. That is, one pin connection portion 163 is formed between a pair of adjacent tip portions 167. Each pin connection portion 163 reaches a tip surface 167a of the tip portion 167. The tip surface 167a is an end surface of the tip portion 167 in the X-axis direction, and is a surface located on the opposite side from the connection portion 166 in the X-axis direction.

[0078] The ferrule 3A according to the second embodiment can also prevent degradation of optical characteristics for the same reasons as those described in the first embodiment. Furthermore, in the ferrule 3A, the inner surface 131a of the fiber hole 131 has a first surface 51 and a second surface 52 that face each other in the Z-axis direction. A plurality of grooves 53 are formed on the first surface 51, aligned in the Y-axis direction and each extending along the X-axis direction. The plurality of first hole portions 141 are a plurality of spaces formed between the second surface 52 and the inner surfaces 53a of the plurality of groove portions 53. The plurality of connection portions 142 are a plurality of spaces formed between the second surface 52 and a plurality of regions 51a of the first surface 51 located between the plurality of grooves 53. This prevents misalignment of the end 2a of the optical fiber 2 in the first hole portion 141.

[0079] When viewed from the X-axis direction, the inner surface 53a of each of the multiple grooves 53 extends in a V-shape. This prevents misalignment of the end 2a of the optical fiber 2 in the first hole 141. Furthermore, the first hole 141 can be formed with a simple configuration. This improves shape reproducibility and analysis accuracy when, for example, analyzing the flow of material (resin) inside the mold for the ferrule 3A. In the analysis, the resin filling region is divided into tetrahedrons for calculation. Reproducing curves and curved surfaces using tetrahedrons increases the calculation cost, so calculations must be performed with reduced shape reproducibility. However, because the inner surface 53c of the ferrule 3A extends in a V-shape (does not include curves or curved surfaces), the difference between the analysis results and the actual molded product can be reduced.

[0080] Although the embodiments have been described above, the present disclosure is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure. In addition, the above-described embodiments may be combined as appropriate.

[0081] The pitch P of the first hole portions 41 may be smaller than 150 μm or larger than 180 μm. When viewed from the X-axis direction, the inner surface 41a of the first hole portion 41 may extend along a shape other than a circle (for example, an ellipse, a polygon, etc.). In the Z-axis direction, the position of the connecting portion 42 does not have to coincide with the position of the center C1 of the first hole portion 41. For example, the connecting portion 42 may be located closer to the main surface 3e or the main surface 3f of the ferrule 3 than the center C1 of the first hole portion 41.

[0082] The ferrule 3 does not have to have the tapered portion 43 and the second hole portion 44. The first hole portion 41 may be directly connected to the groove portion 32. The ferrule 3 does not have to have the groove portion 32.

[0083] In the second embodiment, the groove portions 53 may be U-grooves. Specifically, when viewed from the X-axis direction, the inner surface 53a of each of the plurality of groove portions 53 may extend in a U-shape. When viewed from the X-axis direction, the inner surface 53a of each of the plurality of groove portions 53 may extend in an arc shape. [Explanation of symbols]

[0084] 1...Optical connector 2...Optical fiber 2a...end 3,3A...Ferrule 3a...front end surface 3b…Rear end surface 3c,3d…side 3e, 3f...Main surface 6,6A…Structure 21...Glass fiber 22…Covering layer 23...Core 24...Clad 31,131...fiber holes 32...Groove 32a...Inside 33...Interior space 34...Guide hole 35...Window section 41,141...First hole 41a...Inside 42...Connection 43...Tapered section 44...Second hole 44a...Inner surface 51…1st surface 51a…area 52…Second surface 53...Groove 53a...Inside 61,161...Main body 62,162...Core pin 63,163...Pin connection 65...Thick diameter part 66...Tapered section 67...Small diameter section 67a…Tip surface 131a...Inside 142...Connection 165...Proximal end 166...Connection 167...Tip 167a…Tip surface A1…First area A2…Second area B1,B2,B3…Contact points C1,C2…center

Claims

1. A front end surface and a rear end surface located on the opposite side to the front end surface in the first direction; a fiber hole that opens in the front end surface and into which ends of a plurality of optical fibers aligned in a second direction intersecting the first direction can be inserted, the fiber holes each extend along the first direction and include a plurality of first hole portions into which ends of corresponding optical fibers among the plurality of optical fibers can be inserted, and a plurality of connection portions that respectively connect adjacent first hole portions among the plurality of first hole portions; Ferrule.

2. a pitch of the plurality of first holes in the second direction is 150 μm or more and 180 μm or less; 2. The ferrule according to claim 1.

3. When viewed from the first direction, the inner surfaces of the plurality of first hole portions extend along a circle centered on an axis along the first direction. The ferrule according to claim 1 or 2.

4. In a third direction intersecting the first direction and the second direction, positions of the plurality of connection portions coincide with positions of centers of the plurality of first hole portions.

4. The ferrule according to claim 3.

5. the fiber hole further includes a plurality of second hole portions, each of which is located closer to the rear end face than the plurality of first hole portions in the first direction and into which an end of a corresponding one of the plurality of optical fibers can be inserted; When viewed from the first direction, an inner surface of each of the plurality of second hole portions extends along a circle centered on an axis along the first direction, an inner diameter of each of the second hole portions is larger than an inner diameter of each of the first hole portions; 4. The ferrule according to claim 3.

6. an inner surface of the fiber hole has a first surface and a second surface facing each other in a third direction intersecting the first direction and the second direction; a plurality of grooves aligned in the second direction and each extending along the first direction are formed on the one surface; the plurality of first holes are a plurality of spaces formed between inner surfaces of the plurality of grooves and the second surface, the plurality of connection portions are a plurality of spaces formed between the second surface and a plurality of regions of the first surface located between the plurality of groove portions; The ferrule according to claim 1 or 2.

7. When viewed from the first direction, the inner surface of each of the plurality of grooves extends in a V-shape.

7. The ferrule according to claim 6.

8. When viewed from the first direction, the inner surface of each of the plurality of grooves extends in a U-shape.

7. The ferrule according to claim 6.

9. a plurality of optical fibers; a ferrule for holding the ends of the optical fibers; the ferrule has a front end face, a rear end face located on the opposite side of the front end face in a first direction, and a fiber hole opening in the front end face, the fiber hole has a plurality of first hole portions each extending along the first direction and a plurality of connection portions each connecting adjacent first hole portions among the plurality of first hole portions, an end portion of each of the plurality of optical fibers is inserted into a corresponding one of the plurality of first hole portions; Optical connector.

10. The outer diameter of each of the plurality of optical fibers is 150 μm or more and 180 μm or less.

10. The optical connector according to claim 9.

11. providing a ferrule mold; a step of placing a structure having a plurality of core pins arranged in a predetermined direction and a plurality of pin connection portions that respectively connect adjacent core pins among the plurality of core pins in the mold; and filling the mold with a material for the ferrule to form the ferrule. A method for manufacturing a ferrule.

12. The structure has a body portion, The plurality of core pins extend so as to protrude from the main body portion, Each of the plurality of core pins includes a large diameter portion and a small diameter portion that is located farther from the main body portion than the large diameter portion and has an outer diameter smaller than the outer diameter of the large diameter portion, The plurality of pin connection portions respectively connect the small diameter portions of the adjacent core pins. The method for manufacturing a ferrule according to claim 11.

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