Optical connectors and optical connection structures

Abstract

To provide an optical connector and optical connection structure that can suppress losses due to bending of optical fibers. [Solution] The optical connector 1A comprises a ferrule 10 having a plurality of fiber holes 11 and an introduction hole, and a plurality of optical fibers 20 inserted into the fiber holes 11 from the introduction hole. The introduction hole has a rear end opening on the rear end face 10b opposite to the connection end face 10a of the ferrule 10. The plurality of optical fibers 20 include a plurality of optical fiber groups 40, each containing a plurality of optical fibers 20. The plurality of optical fiber groups 40 are introduced into the introduction hole from the rear end opening and inserted into the fiber holes 11. The fiber holes 11 are formed at different positions in the first direction X on the connection end face 10a. Two or more of the plurality of optical fibers 20 included in the optical fiber group 40 have positions in the second direction Y at the rear end opening that are different from each other.

Description

Technical Field

[0001] The present invention relates to an optical connector and an optical connection structure.

Background Art

[0002] With the increase in transmission capacity in communication networks using optical fibers, the use of multi-core fibers is expected. To apply multi-core fibers to existing communication networks using single-core fibers, a structure for connecting multi-core fibers and single-core fibers is used (for example, see Patent Document 1).

[0003] To connect a multi-core fiber and a single-core fiber, a fan-in / fan-out (FIFO) device may be used. The FIFO device is a conversion device between a multi-core fiber and a single-core fiber.

[0004] The FIFO device includes, for example, a first optical connector for a single-core fiber and a second optical connector for a multi-core fiber. The first optical connector has a structure in which a plurality of optical fibers, which are single-core fibers, are inserted into the fiber holes of the ferrule. By connecting the first optical connector to the second optical connector for a multi-core fiber, a plurality of optical fibers (single-core fibers) can be connected to the multi-core fiber.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] To increase density, it is conceivable to use a multi-core optical connector that utilizes multiple multi-core fibers as the optical connector (second optical connector) on the multi-core fiber side. However, as the number of multicore fibers increases, the number of optical fibers in the optical connector on the single-core fiber side (first optical connector) also increases. Inserting a large number of optical fibers into the ferrule in the first optical connector could lead to increased bending of some of the optical fibers, potentially resulting in greater losses.

[0007] One aspect of the present invention aims to provide an optical connector and an optical connection structure that can suppress losses due to bending of optical fibers. [Means for solving the problem]

[0008] A first aspect of the present invention provides an optical connector comprising a ferrule having a plurality of fiber holes opening on a connection end face and an introduction hole communicating with the fiber holes, and a plurality of optical fibers inserted into the fiber holes from the introduction hole, wherein the introduction hole has a rear end opening on the rear end face of the ferrule opposite to the connection end face, the plurality of optical fibers include a plurality of optical fiber groups having a plurality of optical fibers, the plurality of optical fiber groups are introduced into the introduction hole from the rear end opening and inserted into the fiber holes, the fiber holes are formed at different positions in a first direction on the connection end face, the direction perpendicular to the first direction along the plane perpendicular to the longitudinal direction of the fiber hole is a second direction, and two or more of the plurality of optical fibers included in the optical fiber group have different positions in the second direction at the rear end opening.

[0009] According to a first aspect of the present invention, the dimensions of multiple optical fibers in the first direction can be reduced. Therefore, compared to the case where multiple optical fibers are arranged side by side in the first direction, the bending applied to optical fibers located outside the first direction can be reduced. Thus, losses due to bending of optical fibers can be suppressed.

[0010] A second aspect of the present invention is the optical connector of the first aspect, wherein the plurality of optical fibers included in the optical fiber group are positioned differently from each other in the second direction at the rear end opening.

[0011] A third aspect of the present invention is an optical connector according to the first or second aspect, wherein the plurality of optical fibers included in the optical fiber group are aligned in the second direction at the rear end opening.

[0012] A fourth aspect of the present invention is an optical connector according to any one of the first to third aspects, wherein the pitch of the fiber holes at the connection end face is smaller than the pitch of the optical fibers when the optical fibers are arranged without gaps in the first direction.

[0013] A fifth aspect of the present invention is an optical connector according to any one of the first to fourth aspects, wherein the number of optical fibers included in one optical fiber group is four.

[0014] An optical connection structure according to a sixth aspect of the present invention comprises an optical connector according to any one of the first to fifth aspects, and a second optical connector connected to the optical connector, wherein the second optical connector has a second connection end face that abuts against the connection end face, and a second fiber hole opening to the second connection end face, and a multicore fiber inserted into the second fiber hole and connected to a plurality of optical fibers. [Effects of the Invention]

[0015] According to one aspect of the present invention, it is possible to provide an optical connector and an optical connection structure that can suppress losses due to bending of optical fibers. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view of the optical connector according to the first embodiment. [Figure 2] This is a cross-sectional view of the optical connector according to the first embodiment. It is a view taken along the II-shaped cross-section in Figure 1. [Figure 3]It is a plan view of an optical connector according to the first embodiment. [Figure 4] It is a perspective view of an optical fiber used for the optical connector according to the first embodiment. [Figure 5] In the optical connector according to the first embodiment, it is a schematic diagram showing the arrangement of the optical fiber at the rear end opening of the ferrule. [Figure 6] It is a front view of a part of the connection end face of the optical connector according to the first embodiment. [Figure 7] It is a cross-sectional view of the optical fiber inserted into the fiber hole of the optical connector according to the first embodiment. [Figure 8] It is a perspective view of the second optical connector. [Figure 9] It is a front view of a part of the second connection end face of the second optical connector. [Figure 10] It is a front view of the multi-core fiber at the second connection end face of the second optical connector. [Figure 11] It is a plan view of an optical connection structure according to an embodiment. [Figure 12] It is a cross-sectional view of an optical connection structure according to an embodiment. [Figure 13] It is a perspective view of an optical connector according to the second embodiment. [Figure 14] It is a perspective view of an optical fiber used for the optical connector according to the second embodiment. [Figure 15] In the optical connector according to the second embodiment, it is a schematic diagram showing the arrangement of the optical fiber at the rear end opening of the ferrule. [Figure 16] In the optical connector according to the third embodiment, it is a schematic diagram showing the arrangement of the optical fiber at the rear end opening of the ferrule. [Figure 17] In the optical connector according to the fourth embodiment, it is a schematic diagram showing the arrangement of the optical fiber at the rear end opening of the ferrule.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, an optical connector and an optical connection structure according to an embodiment of the present invention will be described based on the drawings.

[0018] [Optical connector] (First embodiment) Figure 1 is a perspective view of the optical connector 1A according to the first embodiment. Figure 2 is a cross-sectional view of the optical connector 1A. Figure 2 is a view taken along the II-section arrow in Figure 1. Figure 3 is a plan view of the optical connector 1A. Figure 4 is a perspective view of the optical fiber 20 used in the optical connector 1A. Figure 5 is a schematic diagram showing the arrangement of the optical fiber 20 in the rear end opening 10c of the ferrule 10. Figure 6 is a front view of a part of the connection end face 10a of the optical connector 1A. Figure 7 is a cross-sectional view of the bare fiber 21 inserted into the fiber hole 11.

[0019] As shown in Figure 1, the optical connector 1A comprises a ferrule 10 and a plurality of optical fibers 20.

[0020] The ferrule 10 has a connecting end face 10a, a rear end face 10b, a fiber hole 11, two positioning holes 13, and an introduction hole 14 (see Figure 2). The connecting end face 10a is the surface that abuts against other connectors when the optical connector 1A is connected to other connectors. The rear end face 10b is the surface of the ferrule 10 opposite to the connecting end face 10a. The fiber hole 11 and the two positioning holes 13 open to the connecting end face 10a.

[0021] (direction definition) In this specification, the direction parallel to the central axis O of the fiber hole 11 is referred to as the longitudinal direction Z. Along the longitudinal direction Z, the direction from the rear end face 10b of the ferrule 10 toward the connecting end face 10a is referred to as the +Z direction, forward, or tip side. The direction opposite to the +Z direction is referred to as the -Z direction, rear, or base side. One direction perpendicular to the longitudinal direction Z is referred to as the first direction X. The first direction X is the direction in which the two positioning holes 13 are aligned. The direction perpendicular to both the longitudinal direction Z and the first direction X is referred to as the second direction Y, vertical direction, or height direction. One of the directions of the second direction Y is referred to as the +Y direction, or upward. The direction opposite to the +Y direction is referred to as the -Y direction, or downward. The second direction Y is perpendicular to the X direction along the plane perpendicular to the longitudinal direction Z.

[0022] At the connection end face 10a, the multiple fiber holes 11 are arranged between two positioning holes 13. The multiple fiber holes 11 are formed at different positions in the first direction X. The multiple fiber holes 11 are formed side by side in the first direction X. The multiple fiber holes 11 may be formed at intervals in the first direction X, or they may be formed without any intervals.

[0023] The optical connector 1A shown in Figure 1 is the female side, and the relative position of optical connector 1A and the other optical connector is determined by inserting the positioning pin of the other optical connector into the positioning hole 13. However, optical connector 1A may also be the male side. That is, optical connector 1A may have positioning pins instead of positioning holes 13.

[0024] As shown in Figure 2, the introduction hole 14 opens on the rear end surface 10b. The opening of the introduction hole 14 formed on the rear end surface 10b is the rear end opening 10c. The introduction hole 14 communicates with the fiber hole 11.

[0025] The connecting end face 10a is inclined with respect to a virtual plane P that is perpendicular to the longitudinal direction Z when viewed from the first direction X. The inclined connecting end face 10a is formed, for example, by polishing the end face of the ferrule 10. The angle between the connecting end face 10a and the virtual plane P is, for example, 8°. However, this angle can be changed. By inclining the connecting end face 10a in this way, the amount of light reflected at the connection point can be reduced. However, the connecting end face 10a does not have to be inclined.

[0026] The ferrule 10 is formed from, for example, a resin or ceramic. Examples of resins include polyetheretherketone resin (PEEK), polyarylene sulfide resin (PAS) (e.g., polyphenylene sulfide resin (PPS)), polyethersulfone resin (PES), polyetherimide resin (PEI), and liquid crystalline resin (LCP) (melting point of 300°C or higher). An example of a ceramic is zirconia.

[0027] As shown in Figure 4, the optical fiber 20 has a bare fiber 21 and a coating 22. The bare fiber 21 is made of, for example, quartz glass. The coating 22 partially covers the bare fiber 21. The coating 22 is made of a resin or the like. For example, the material of the coating 22 may be a UV-curable resin. The portion of the optical fiber 20 including the tip has the bare fiber 21 exposed.

[0028] The bare fiber 21 has a small diameter portion 21a, a large diameter portion 21b, and a tapered portion 21c. The small diameter portion 21a is the portion of the bare fiber 21 that includes the tip. The outer diameter of the small diameter portion 21a is smaller than the outer diameter of the large diameter portion 21b. The tapered portion 21c is located between the small diameter portion 21a and the large diameter portion 21b. The tapered portion 21c has an outer diameter that gradually decreases towards the tip. The small diameter portion 21a and the tapered portion 21c can be formed by thinning the bare fiber 21 by etching or the like.

[0029] As shown in Figure 7, the optical fiber 20 is a single-core fiber. The bare fiber 21 has a core 21d and a cladding 21e surrounding the core 21d.

[0030] As shown in Figures 1 and 5, the multiple optical fibers 20 include multiple optical fiber groups 40. Each optical fiber group 40 has multiple optical fibers 20. In this embodiment, there are four optical fiber groups 40. Each optical fiber group 40 has four optical fibers 20.

[0031] As shown in Figure 2, the multiple optical fibers 20 included in the optical fiber group 40 are arranged in a line in the second direction Y at the rear end opening 10c. The multiple optical fibers 20 included in the optical fiber group 40 may be arranged with intervals between them in the second direction Y, or they may be arranged without any intervals between them.

[0032] As shown in Figure 5, the multiple optical fibers 20 included in the optical fiber group 40 all have different positions in the second direction Y at the rear end opening 10c. In this embodiment, of the four optical fibers 20, the first optical fiber 20A is at the highest position. The second optical fiber 20B is at the second highest position. The third optical fiber 20C is at the third highest position. The fourth optical fiber 20D is at the lowest position. The four optical fibers 20 do not overlap when viewed from the first direction X. Note that of the multiple optical fibers 20 included in the optical fiber group 40, it is sufficient that two or more of them have different positions in the second direction Y at the rear end opening 10c.

[0033] Multiple optical fiber groups 40 are formed in a row in the first direction X at the rear end opening 10c. The multiple optical fiber groups 40 may be arranged with intervals between them in the first direction X, or they may be arranged without any intervals between them. In this embodiment, since four optical fiber groups 40 are arranged in the first direction X, the multiple optical fibers 20 are arranged in a rectangular grid (matrix) of 4 rows and 4 columns at the rear end opening 10c.

[0034] As shown in Figure 2, the optical fiber group 40 is introduced into the introduction hole 14 from the rear end opening 10c. Multiple optical fibers 20 belonging to the optical fiber group 40 are bundled as bare fibers 21 and inserted into the fiber hole 11. Multiple bare fibers 21 are inserted into one fiber hole 11 at the small diameter portion 21a. As shown in Figure 6, the tip surfaces of the bare fibers 21 are exposed to the connection end surface 10a. In this embodiment, at the connection end surface 10a, four bare fibers 21 belonging to one optical fiber group 40 are arranged in a 2x2 rectangular grid (matrix).

[0035] As shown in Figure 3, each of the multiple optical fiber groups 40 is inserted into a different fiber hole 11. In this embodiment, the first optical fiber group 40A of the four optical fiber groups 40 is inserted into the first fiber hole 11A of the four fiber holes 11. The second optical fiber group 40B is inserted into the second fiber hole 11B. The third optical fiber group 40C is inserted into the third fiber hole 11C. The fourth optical fiber group 40D is inserted into the fourth fiber hole 11D.

[0036] As shown in Figure 2, the adhesive 30 has the function of fixing multiple optical fibers 20 to the ferrule 10. The adhesive 30 is filled in the gap between the inner surface of the fiber hole 11 and the outer surface of the optical fiber 20. For example, a thermosetting resin can be used as the adhesive 30. The adhesive 30 may also be an epoxy resin.

[0037] As shown in Figure 3, the pitch P1 of the fiber holes 11 at the connection end face 10a is compared with the pitch P2 of the optical fibers 20 when the optical fibers 20 with the covering 22 are arranged without gaps in the first direction X. The relationship between pitch P1 and pitch P2 is not particularly limited. Pitch P1 may be smaller than pitch P2. Pitch P1 may be equal to pitch P2. Pitch P1 may be larger than pitch P2. Pitch P2 is, for example, the pitch at the rear end opening 10c. Pitch P2 is, for example, equal to the outer diameter of the covering 22.

[0038] [How to assemble an optical connector] The assembly of optical connector 1A is performed, for example, by following the procedure below.

[0039] Multiple optical fibers 20 are prepared. The coating 22 of the optical fibers 20 is partially removed to expose the bare fibers 21. A portion of the exposed bare fiber 21 is reduced in diameter by etching or the like. By adjusting the immersion time in the etching solution for each position along the longitudinal direction of the bare fiber 21, a small-diameter portion 21a and a tapered portion 21c can be formed (see Figure 4).

[0040] As shown in Figure 2, multiple optical fibers 20 are introduced into the introduction hole 14 of the ferrule 10 from the rear end opening 10c, and a bare fiber 21 is inserted into the fiber hole 11. Uncured adhesive 30 is injected into the internal space of the ferrule 10. The adhesive 30 may be actively forced into the fiber hole 11 by suction from the opening of the connecting end face 10a. Alternatively, the adhesive 30 may be forced into the fiber hole 11 by capillary force generated within the fiber hole 11.

[0041] The optical fiber 20 is fixed to the ferrule 10 by curing the adhesive 30. For example, if the adhesive 30 is a thermosetting resin such as epoxy resin, the adhesive 30 is heated to a temperature above its curing temperature. For example, if the adhesive 30 is a UV-curing resin, the adhesive 30 is cured by irradiating it with UV light. This results in the optical connector 1A shown in Figure 1, etc.

[0042] [Second optical connector and optical connection structure C] Figure 8 is a perspective view of the second optical connector 100 of the optical connection structure C according to the embodiment. Figure 9 is a front view of a part of the second connection end face 110a of the second optical connector 100. Figure 10 is a front view of the multicore fiber 120 at the second connection end face 110a. Figure 11 is a plan view of the optical connection structure C according to the embodiment. Figure 12 is a cross-sectional view of the optical connection structure C according to the embodiment.

[0043] As shown in Figure 8, the second optical connector 100 comprises a second ferrule 110 and a plurality of multicore fibers 120. The second ferrule 110 has a second connection end face 110a, a plurality of second fiber holes 111 opening in the second connection end face 110a, two positioning pins 113, and an introduction hole 114 (see Figure 12).

[0044] At the second connection end face 110a, the multiple second fiber holes 111 are positioned between the two positioning pins 113. The second fiber holes 111 open to the second connection end face 110a. The multiple second fiber holes 111 are formed side by side in the first direction X. The multiple second fiber holes 111 may be formed at intervals in the first direction X, or they may be formed without any intervals. The pitch of the second fiber holes 111 is equal to the pitch of the fiber holes 11 of the optical connector 1A (see Figure 1).

[0045] As shown in Figures 11 and 12, the second connection end face 110a abuts against the connection end face 10a of the optical connector 1A. The second connection end face 110a contacts the connection end face 10a. As shown in Figure 12, the entry hole 114 opens on the rear end face of the second ferrule 110 (the face opposite to the second connection end face 110a). The entry hole 114 communicates with the second fiber hole 111.

[0046] The second ferrule 110 is formed from, for example, resin, ceramic, etc. Examples of resins include PEEK, PAS (e.g., PPS), PES, PEI, LCP (melting point of 300°C or higher), etc. Examples of ceramics include zirconia.

[0047] The multicore fiber 120 has a bare fiber 121 and a coating 122. The portion of the multicore fiber 120 including the tip has the bare fiber 121 exposed. The multicore fiber 120 is inserted from the entry hole 114 into the second fiber hole 111. As shown in Figure 9, the tip surface of the bare fiber 121 is exposed to the second connection end surface 110a.

[0048] As shown in Figure 10, the bare fiber 121 has multiple cores 121d and a cladding 121e surrounding the cores 121d. In this embodiment, the multicore fiber 120 has four cores 121d. The four cores 121d are arranged in a 2x2 rectangular grid (matrix).

[0049] As shown in Figure 11, the multiple multicore fibers 120 are arranged in a line in the first direction X. The multiple multicore fibers 120 may be spaced apart in the first direction X, or they may be arranged without any spacing. In this embodiment, there are four multicore fibers 120.

[0050] As shown in Figure 12, the adhesive 130 is injected into the second ferrule 110 to fix the multicore fiber 120 to the second ferrule 110.

[0051] As shown in Figures 11 and 12, the optical connection structure C comprises an optical connector 1A (see Figure 1), a second optical connector 100 (see Figure 8), and an adapter 2.

[0052] Optical connector 1A and second optical connector 100 are connected by butting their connection end faces 10a and 110a. The positioning pin 113 shown in Figure 8 is inserted into the positioning hole 13 (see Figure 1) of the ferrule 10 of the optical connector 1A, thereby determining the relative position between the second optical connector 100 and the optical connector 1A.

[0053] The adapter 2 has the function of maintaining a state in which the connection end face 10a of the optical connector 1A and the second connection end face 110a of the second optical connector 100 are in contact with each other at an appropriate position. The adapter 2 has a through hole 2a that penetrates the adapter 2 in the longitudinal direction Z. The optical connector 1A and the second optical connector 100 are inserted into the through hole 2a, respectively.

[0054] The leading ends of the optical fibers 20 of the multiple optical fiber groups 40 of the optical connector 1A (see Figure 6) are each butted with the leading ends of the multiple multicore fibers 120 of the second optical connector 100 (see Figure 9). The cores 21d of the optical fibers 20 (see Figure 7) are each optically connected to the cores 121d of the multicore fibers 120 (see Figure 10).

[0055] [Effects of the optical connector 1A and optical connection structure C according to this embodiment] In the optical connector 1A according to this embodiment (see Figure 1), two or more of the multiple optical fibers 20 included in the optical fiber group 40 have different positions in the second direction Y at the rear end opening 10c. Therefore, the dimensions of the multiple optical fibers 20 in the first direction X can be reduced. Consequently, the bending applied to the optical fibers 20 located outside the first direction X can be reduced compared to the case where the multiple optical fibers 20 are arranged in a line in the first direction X. Thus, losses due to bending of the optical fibers 20 can be suppressed.

[0056] In optical connector 1A (see Figure 1), the multiple optical fibers 20 included in the optical fiber group 40 have different positions in the second direction Y at the rear end opening 10c. In the example shown in Figure 5, all four optical fibers 20 included in one optical fiber group 40 have different positions in the second direction Y. Therefore, the dimension in the first direction X of the multiple optical fibers 20 can be reduced. Thus, losses due to bending of the optical fibers 20 can be suppressed.

[0057] In optical connector 1A (see Figure 1), the multiple optical fibers 20 included in the optical fiber group 40 are aligned in the second direction Y at the rear end opening 10c. Therefore, the dimension of the multiple optical fibers 20 in the first direction X can be reduced. Thus, losses due to bending of the optical fibers 20 can be suppressed.

[0058] As shown in Figure 3, when the pitch P1 of the fiber hole 11 is smaller than the pitch P2 of the optical fibers 20 when they are arranged without gaps in the first direction X, the optical connector 1A can particularly enhance the effect of reducing loss due to bending of the optical fibers 20 for the following reasons. When the pitch P1 is smaller than the pitch P2, the pitch of the optical fibers 20 at the rear end of the ferrule 10 is larger than that at the front end, so the bending applied to the optical fibers 20 tends to be larger. In contrast, with the optical connector 1A, the dimension of the multiple optical fibers 20 in the first direction X can be reduced at the rear end of the ferrule 10, so the bending of the optical fibers 20 can be reduced and loss can be reduced.

[0059] Since the optical fiber group 40 contains four optical fibers 20, the dimension of the optical fiber group 40 in the second direction Y can be reduced. Therefore, the dimension of the ferrule 10 in the second direction Y can be reduced. Thus, the thickness dimension of the optical connector 1A can be reduced.

[0060] The optical connection structure C according to this embodiment includes an optical connector 1A and a second optical connector 100. Therefore, the dimension of the multiple optical fibers 20 in the first direction X can be reduced in the optical connector 1A. Thus, losses due to bending of the optical fibers 20 can be suppressed.

[0061] [Optical connector] (Second embodiment) Next, the optical connector 1B according to the second embodiment will be described. The basic configuration of the optical connector 1B is the same as that of the optical connector 1A (see Figure 1). Therefore, components that are the same as those of the optical connector 1A are given the same reference numerals and their descriptions are omitted, and only the differences will be described.

[0062] Figure 13 is a perspective view of the optical connector 1B. Figure 14 is a perspective view of the optical fiber 20 used in the optical connector 1B. Figure 15 is a schematic diagram showing the arrangement of the optical fiber 20 in the rear end opening 210c of the ferrule 10 of the optical connector 1B.

[0063] As shown in Figure 13, the optical connector 1B comprises a ferrule 10 and a plurality of optical fibers 20. As shown in Figure 14, multiple optical fibers 20 constitute multiple optical fiber groups 240. Each optical fiber group 240 has multiple optical fibers 20. In this embodiment, there are four optical fiber groups 240. Each optical fiber group 240 has four optical fibers 20.

[0064] As shown in Figure 15, the four optical fibers 20 belonging to one optical fiber group 240 are arranged in a 2x2 rectangular grid (matrix) at the rear end opening 210c. The four optical fibers 20 belonging to the optical fiber group 240 can be arranged in a configuration such as a first group consisting of multiple optical fibers 20E, 20F aligned in the first direction X, and a second group consisting of multiple optical fibers 20G, 20H aligned in the first direction X, both aligned in the second direction Y. Therefore, it can be said that two or more of the four optical fibers 20 are at different positions in the second direction Y at the rear end opening 210c.

[0065] Multiple optical fiber groups 240 are formed in a row in the first direction X at the rear end opening 210c. In this embodiment, since four optical fiber groups 240 are aligned in the first direction X, the multiple optical fibers 20 are arranged in a 2x8 rectangular grid (matrix) at the rear end opening 210c.

[0066] In the optical connector 1B according to this embodiment, two or more of the multiple optical fibers 20 included in the optical fiber group 240 have different positions in the second direction Y at the rear end opening 210c. Therefore, the dimensions of the multiple optical fibers 20 in the first direction X can be reduced. Consequently, the bending applied to the optical fibers 20 located outside the first direction X can be reduced compared to the case where the multiple optical fibers 20 are arranged in a line in the first direction X. Thus, losses due to bending of the optical fibers 20 can be suppressed.

[0067] [Optical connector] (Third embodiment) Next, the optical connector according to the third embodiment will be described. Components similar to those of optical connector 1A are denoted by the same reference numerals and their descriptions are omitted; only the differences will be described.

[0068] Figure 16 is a schematic diagram showing the arrangement of the optical fiber 20 at the rear end opening 310c of the ferrule. As shown in Figure 16, the four optical fibers 20 belonging to one optical fiber group 340 are arranged along a straight line that slopes upward in the first direction X (to the right in Figure 16) at the rear end opening 310c. Therefore, it can be said that two or more of the four optical fibers 20 have different positions in the second direction Y at the rear end opening 310c. Multiple optical fiber groups 340 are formed side by side in the first direction X at the rear end opening 310c.

[0069] In the optical connector according to this embodiment, two or more of the multiple optical fibers 20 included in the optical fiber group 340 have different positions in the second direction Y at the rear end opening 310c. Therefore, the dimensions of the multiple optical fibers 20 in the first direction X can be reduced. Consequently, the bending applied to the optical fibers 20 located outside the first direction X can be reduced compared to the case where the multiple optical fibers 20 are arranged in a line in the first direction X. Thus, losses due to bending of the optical fibers 20 can be suppressed.

[0070] [Optical connector] (Fourth embodiment) Next, the optical connector according to the fourth embodiment will be described. Components similar to those of optical connector 1A are denoted by the same reference numerals and their descriptions are omitted; only the differences will be described.

[0071] Figure 17 is a schematic diagram showing the arrangement of the optical fiber 20 at the rear end opening 410c of the ferrule. As shown in Figure 17, the four optical fibers 20 belonging to one optical fiber group 440 are arranged in a configuration at the rear end opening 410c such that the first group consists of optical fibers 20I and 20J, and the second group consists of multiple optical fibers 20J and 20K aligned in the first direction X are aligned in the second direction Y. The optical fibers 20I and 20J of the first group are arranged along a straight line that slopes downward toward the first direction X (to the right in Figure 17). The optical fibers 20K and 20L of the second group are arranged along a straight line that slopes downward toward the first direction X (to the right in Figure 17). Therefore, it can be said that two or more of the four optical fibers 20 are at different positions in the second direction Y at the rear end opening 210c. Multiple optical fiber groups 440 are formed aligned in the first direction X at the rear end opening 410c.

[0072] In the optical connector according to this embodiment, two or more of the multiple optical fibers 20 included in the optical fiber group 440 have different positions in the second direction Y at the rear end opening 410c. Therefore, the dimensions of the multiple optical fibers 20 in the first direction X can be reduced. Consequently, the bending applied to the optical fibers 20 located outside the first direction X can be reduced compared to the case where the multiple optical fibers 20 are arranged in a line in the first direction X. Thus, losses due to bending of the optical fibers 20 can be suppressed.

[0073] The technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[0074] For example, the number of optical fiber groups 40 in an optical connector is not particularly limited. The number of optical fiber groups 40 may be multiple (any number of two or more). The number of optical fibers 20 constituting the optical fiber group 40 is not particularly limited. The number of optical fibers 20 constituting the optical fiber group 40 may be multiple (any number of two or more).

[0075] Furthermore, without departing from the spirit of the present invention, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments and modifications may be combined as appropriate. [Explanation of Symbols]

[0076] 1A, 1B…Optical connector 10, 210…Ferrule 10a…Connecting end face 10b…Rear end face 10c, 210c, 310c, 410c…Rear end opening 11…Fiber hole 14…Inlet hole 20, 20A~20L…Optical fiber 40, 240, 340, 440…Optical fiber group 100…Second optical connector 110…Second ferrule 110a…Second connecting end face 111…Second fiber hole 120…Multicore fiber C…Optical connection structure X…First direction Y…Second direction

Claims

1. A ferrule having a plurality of fiber holes opening on the connecting end face, and an introduction hole communicating with the fiber holes, Multiple optical fibers are inserted from the introduction hole into the fiber hole, Equipped with, The introduction hole has a rear end opening on the rear end face of the ferrule opposite to the connecting end face, The plurality of optical fibers include a plurality of optical fiber groups having a plurality of optical fibers, Multiple optical fiber groups are introduced from the rear end opening into the introduction hole and inserted into the respective fiber holes. The fiber holes are formed at the connection end face at different positions in the first direction, The direction perpendicular to the first direction along the plane perpendicular to the longitudinal direction of the fiber hole is the second direction. Of the multiple optical fibers included in the optical fiber group, two or more have different positions in the second direction at the rear end opening. Optical connector.

2. The plurality of optical fibers included in the optical fiber group have different positions in the second direction at the rear end opening. The optical connector according to claim 1.

3. Multiple optical fibers included in the optical fiber group are aligned in the second direction at the rear end opening. The optical connector according to claim 1.

4. The pitch of the fiber holes at the connecting end face is smaller than the pitch of the optical fibers when the optical fibers are arranged without gaps in the first direction. The optical connector according to claim 1.

5. The number of optical fibers included in one optical fiber group is four. The optical connector according to claim 1.

6. An optical connector according to any one of claims 1 to 5, A second optical connector connected to the aforementioned optical connector, Equipped with, The second optical connector is, A second ferrule having a second connecting end face that abuts against the aforementioned connecting end face, and a second fiber hole that opens into the second connecting end face, A multicore fiber inserted into the second fiber hole and connected to a plurality of optical fibers, Having, Optical connection structure.

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