Ferrule, optical connector, and optical fiber ribbon

Abstract

To provide a ferrule, an optical connector, and a coated optical fiber ribbon capable of preventing deterioration in optical characteristics.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 are open to the front end surface and into which end portions of a plurality of glass fibers arranged in a second direction intersecting the first direction can be inserted. A width of the fiber hole along the second direction is larger than a width of the fiber hole along a third direction intersecting the first direction and the second direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a ferrule, an optical connector, and a ribbon optical fiber. [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 ribbon optical fiber that can prevent degradation of optical properties. [Means for solving the problem]

[0006] A ferrule according to one embodiment 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 a fiber hole that opens into the front end face and into which ends of multiple glass fibers aligned in a second direction that intersects the first direction can be inserted, and the width of the fiber hole along the second direction is greater than the width of the fiber hole along a third direction that intersects the first and second directions. [Effects of the Invention]

[0007] According to the present disclosure, a ferrule, an optical connector, and a ribbon optical fiber 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 an embodiment. [Figure 2] FIG. 2 is a plan view of the optical connector shown in FIG. [Figure 3] FIG. 3 is a perspective view showing the optical fiber ribbon 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 view showing the front end face of the ferrule shown in FIG. [Figure 6] FIG. 6 is a diagram showing the internal structure of the ferrule shown in FIG. [Figure 7] FIG. 7 is a perspective view showing a portion of a structure used in manufacturing the ferrule shown in FIG. 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 a fiber hole opening in the front end face and into which ends of multiple glass fibers aligned in a second direction intersecting the first direction can be inserted, and the width of the fiber hole along the second direction is greater than the width of the fiber hole along a third direction intersecting the first and second directions.

[0010] In this ferrule, the fiber holes are holes into which the ends of multiple glass fibers aligned in a second direction intersecting the first direction can be inserted, and the width of the fiber hole along the second direction is greater than the width of the fiber hole along a third direction intersecting the first and second directions. Conventional ferrules, in which one optical fiber is inserted into each of multiple independent (separate) hole portions, are manufactured by placing multiple independent core pins in a ferrule mold and filling the mold with ferrule material (e.g., molten resin). However, for example, the narrower the spacing between the core pins used to form the ferrule holes, the less material is properly filled between the core pins, which can result in unintended areas of the ferrule that are unfilled with material. In contrast, in the above ferrule, the ends of multiple glass fibers are inserted into a single fiber hole that is formed with a wide width in the second direction in which the ends of the glass fibers are aligned. The fiber hole can be formed, for example, using a single member formed by connecting multiple core pins. This reduces the amount of ferrule material that needs to be filled between the core pins during the ferrule manufacturing process. This reduces the possibility of unintended unfilled areas of the ferrule material (e.g., air traps, weld lines) occurring in the areas that form the fiber holes, and allows the fiber holes to be formed in the desired positions and shapes, thereby preventing degradation of the optical properties of the ferrule.

[0011] (2) In the ferrule of (1) above, the fiber holes may each extend along the first direction and have a plurality of hole portions into which ends of corresponding glass fibers among the plurality of glass fibers can be inserted, the plurality of hole portions may be aligned in the second direction, and adjacent hole portions among the plurality of hole portions may be connected to each other in the second direction. In this case, it is possible to prevent displacement of the ends of the plurality of glass fibers inserted into the fiber holes.

[0012] (3) In the ferrule of (1) or (2) above, the pitch of the plurality of holes in the second direction may be 110 μm or more and 140 μm or less. In this case, the ferrule can be made smaller. Furthermore, since more holes can be formed in the ferrule, the number of glass fibers inserted into the ferrule can be increased, thereby improving the optical characteristics.

[0013] (4) The ferrule according to any one of (1) to (3) above may further include a plurality of grooves each extending along the first direction, and the plurality of grooves may be located closer to the rear end face than the fiber holes in the first direction. In this case, the ends of the plurality of glass fibers can be easily inserted into the fiber holes using the grooves.

[0014] (5) The ferrule according to any one of (1) to (4) above may further include an internal space that opens at the rear end face and communicates with the fiber hole. In this case, the internal space can accommodate the ends of multiple glass fibers.

[0015] (6) The optical connector of the present disclosure includes a ribbon fiber having a plurality of glass fibers, each having a core and a cladding, and a coating layer covering the plurality of glass fibers; a ferrule having a front end face, a rear end face located opposite the front end face in a first direction, and a fiber hole opening in the front end face, wherein the width of the fiber hole along a second direction intersecting the first direction is greater than the width of the fiber hole along a third direction intersecting the first and second directions, and the ends of the plurality of glass fibers are aligned in the second direction and inserted into the fiber hole while exposed from the coating layer, and the ends of adjacent glass fibers among the plurality of glass fibers are in contact with each other. In this optical connector, for the same reasons as those described above, the fiber hole can be formed in a desired position and shape. Therefore, this optical connector can prevent degradation of optical characteristics.

[0016] (7) In the optical connector of (6), the ferrule may further have an internal space that opens at the rear end face and is connected to the fiber hole, and the portions of the plurality of glass fibers that are covered with the coating layer may be accommodated in the internal space. In this case, the ends of the plurality of glass fibers may be accommodated in the internal space.

[0017] (8) The ribbon core wire of the present disclosure comprises a plurality of glass fibers, each including a core and a cladding, and a coating layer that collectively covers the plurality of glass fibers, the ends of the plurality of glass fibers being aligned in a predetermined direction, and the ends of adjacent glass fibers among the plurality of glass fibers being in contact with each other.

[0018] In this ribbon fiber, the coating layer collectively coats multiple glass fibers, and the ends of adjacent glass fibers among the multiple glass fibers are in contact with each other. This prevents the ends of the glass fibers from shifting position when inserted into the fiber holes of the ferrule described above, for example. Therefore, this ribbon fiber can prevent degradation of optical characteristics. Furthermore, compared to when each glass fiber is individually coated with an independent coating layer, the width of the ribbon fiber can be made smaller, allowing for the miniaturization of the ferrule into which the ribbon fiber is inserted.

[0019] [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.

[0020] The configuration of an optical connector 1 according to one embodiment will be described with reference to Fig. 1 to Fig. 6. Fig. 1 is a perspective view showing an optical connector according to this embodiment. Fig. 2 is a plan view of the optical connector shown in Fig. 1. Fig. 3 is a perspective view showing the ribbon optical fiber shown in Fig. 1. Fig. 4 is a cross-sectional view of the ferrule taken along line IV-IV shown in Fig. 1. Fig. 5 is a view showing the front end face of the ferrule shown in Fig. 1. Fig. 6 is a view showing the internal structure of the ferrule shown in Fig. 1.

[0021] 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 ribbon fiber 2 and a ferrule 3.

[0022] The ribbon fiber 2 transmits input light (optical signal). As shown in FIG. 3, the ribbon fiber 2 has a plurality of glass fibers (optical fibers) 21 and a coating layer 22. In this example, the number of the glass fibers 21 is 12. The end 21a of each glass fiber 21 extends along the X-axis direction. The glass fiber 21 includes a core 23 and a cladding 24 surrounding the core 23. The cladding 24 has a refractive index different from that of the core 23. The refractive index of the core 23 is higher than that of the cladding 24. As a result, the light input to the ribbon fiber 2 is guided in the core 23. The cross section of the glass fiber 21 is circular.

[0023] The coating layer 22 coats the plurality of glass fibers 21 collectively. That is, the plurality of glass fibers 21 are covered by one continuous coating layer 22. The coating layer 22 covers the outer periphery of the glass fiber 21. The coating layer 22 is in direct contact with the surface (clad 24) of the glass fiber 21. A portion of the tip of the coating layer 22 is removed from the ribbon fiber 2. That is, the end 21a of the glass fiber 21 has an exposed portion that is not covered by the coating layer 22. The exposed portion of the glass fiber 21 is located closer to the tip surface of the glass fiber 21 than the portion of the glass fiber 21 that is covered by the coating layer 22. The coating layer 22 is formed of, for example, a resin.

[0024] The ends 21a of the multiple glass fibers 21 are aligned in the Y-axis direction (a predetermined direction). The ends 21a of adjacent glass fibers 21 among the multiple glass fibers 21 are in contact with each other. The clad 24 of each glass fiber 21 is in contact with the clad 24 of an adjacent glass fiber 21 in the Y-axis direction. As an example, the outer diameter of the glass fiber 21 is approximately 125 μm. The pitch of the multiple glass fibers 21 in the Y-axis direction is approximately 125 μm. The pitch of the glass fibers 21 is the distance between the centers of adjacent glass fibers 21 when viewed from the X-axis direction.

[0025] The ferrule 3 is, for example, an MT ferrule. The ferrule 3 holds the ends of the ribbon fiber 2 (ends 21a of the multiple glass fibers 21). 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 to the front end face 3a in the X-axis direction. The side face 3d is located on the opposite side to the side face 3c in the Y-axis direction. The main face 3f is located on the opposite side to the main face 3e in the Z-axis direction.

[0026] 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.

[0027] 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 21a of the plurality of glass fibers 21 can be inserted. The fiber hole 31 has a hollow shape and opens at the front end face 3a. The ends 21a of the plurality of glass fibers 21 aligned in the Y-axis direction can be inserted into the fiber hole 31.

[0028] The fiber hole 31 includes a plurality of hole portions 41. Each of the plurality of hole portions 41 is a hole extending along the X-axis direction. One end of each hole portion 41 opens to the front end face 3a, and the other end is connected to the corresponding groove portion 32. In this example, the number of the plurality of hole portions 41 matches the number of the plurality of glass fibers 21 to be inserted. In this example, the number of the hole portions 41 is 12.

[0029] As shown in Fig. 5, each hole 41 can receive an end 21a of a corresponding glass fiber 21 among the plurality of glass fibers 21. That is, one glass fiber 21 is inserted into one hole 41. For ease of explanation, Fig. 5 illustrates only the glass fibers 21 inserted into three of the plurality of holes 41, and does not illustrate the glass fibers 21 inserted into the other holes 41. An exposed portion of the end 21a of the glass fiber 21 that is not covered with the coating layer 22 is inserted into the hole 41. That is, the end 21a of the plurality of glass fibers 21 is inserted into the fiber hole 31 in a state where it is exposed from the coating layer 22.

[0030] When viewed from the X-axis direction, the inner surfaces 41a of each of the plurality of holes 41 extend (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 hole 41 is approximately equal to the outer diameter of the glass fiber 21. In this example, the inner diameter of the hole 41 is approximately 125 μm.

[0031] The multiple holes 41 are lined up in the Y-axis direction. The pitch P of the multiple holes 41 in the Y-axis direction matches the pitch of the multiple glass fibers 21. The pitch P of the holes 41 is the distance between the centers C1 of adjacent holes 41 when viewed from the X-axis direction. In this example, the pitch P of the holes 41 is approximately 125 μm. The pitch P of the holes 41 may be, for example, 110 μm or more and 140 μm or less. The pitch P of the holes 41 does not have to match exactly the pitch of the glass fibers 21.

[0032] The multiple holes 41 are lined up without any gaps in the Y-axis direction. Adjacent holes 41 among the multiple holes 41 are connected to each other in the Y-axis direction. Adjacent holes 41 are directly connected to each other spatially without any intervening space. That is, the internal space of each hole 41 is not divided. The internal spaces of the multiple holes 41 are connected to each other and form one fiber hole 31 (one space). When viewed from the X-axis direction, the circle along the inner surface 41a of each hole 41 contacts or overlaps with the circle along the inner surface 41a of an adjacent hole 41. The inner surface 41a of each hole 41 is directly connected to the inner surface 41a of an adjacent hole 41. The end 21a of the glass fiber 21 inserted in each hole 41 contacts the end 21a of the glass fiber 21 inserted in the adjacent hole 41.

[0033] As shown in FIG. 5, the width W1 of the fiber hole 31 along the Y-axis direction is larger than the width W2 of the fiber hole 31 along the Z-axis direction. The widths W1 and W2 of the fiber hole 31 are the maximum widths of the openings of the fiber holes 31 at the front end face 3a. The width W1 is, for example, about 1500 μm, and the width W2 is, for example, about 125 μm. The width W3 along the Z-axis direction of the connection portion 42 between each hole 41 and an adjacent hole 41 is smaller than the width W2 and the outer diameter of the glass fiber 21. Because the width W3 is smaller than the outer diameter of the glass fiber 21, the end 21a of the glass fiber 21 inserted into the corresponding hole 41 is prevented from moving to another hole 41 (misalignment of the glass fiber 21 in the Y-axis direction).

[0034] The multiple grooves 32 are formed on the inner surface of the ferrule 3 at positions closer to the rear end face 3b in the X-axis direction than the multiple hole portions 41. That is, the multiple grooves 32 are positioned closer to the rear end face 3b in the X-axis direction than the fiber holes 31. 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 hole portion 41, and the other end is connected to the internal space 33, which will be described later.

[0035] In each groove 32, an end 21a of a corresponding glass fiber 21 among the plurality of glass fibers 21 can be placed. That is, one glass fiber 21 is placed in one groove 32. When viewed from the X-axis direction, the inner surface 32a of the groove 32 coincides with the inner surface 41a of the corresponding hole 41. That is, when viewed from the X-axis direction, the inner surface 32a of the groove 32 extends (in an arc shape) along a circle whose center is an axis along the X-axis direction.

[0036] The pitch of the grooves 32 in the Y-axis direction matches the pitch P of the holes 41. 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 125 μm. The pitch of the grooves 32 may be, for example, 110 μm or more and 140 μm or less. The pitch of the grooves 32 does not have to match the pitch P of the holes 41 exactly.

[0037] The internal space 33 is a housing portion capable of housing an end portion of the ribbon fiber 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 houses portions of the multiple glass fibers 21 that are 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.

[0038] Ends 21a of the multiple glass fibers 21 are accommodated in the internal space 33 through openings in the rear end face 3b. The end 21a of each glass fiber 21 accommodated in the internal space 33 is placed in the corresponding groove 32 and then inserted into the corresponding hole 41. The tip end face of the glass fiber 21 inserted into the hole 41 is exposed to the outside of the ferrule 3 through the opening of the hole 41 in the front end face 3a.

[0039] The ferrule 3 is disposed in the internal space 33 and further includes an adhesive (not shown) for fixing the end of the ribbon fiber 2 (the plurality of glass fibers 21) 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.

[0040] 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.

[0041] [Ferrule manufacturing method] Next, a method for manufacturing the ferrule 3 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 in 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 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 and a plurality of core pins 62 aligned in a predetermined direction (Y-axis direction). The main body 61 is a part 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.

[0042] The multiple core pins 62 are portions for forming the fiber hole 31 and the groove portion 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. The core pins 62 have a circular shape in a cross section perpendicular to the direction in which the core pins 62 extend (the X-axis direction). The outer diameter of the core pins 62 matches the inner diameter of the hole portion 41 and the groove portion 32 of the ferrule 3. Adjacent core pins 62 are connected to each other. That is, the multiple core pins 62 constitute a single member 63 that is integrally formed.

[0043] 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 (internal space of the mold). At this time, a catcher that holds the end of the core pin 62 may be used to fix the core pin 62. Specifically, a hole corresponding to the shape of the core pin 62 is formed in the catcher, and the end of the core pin 62 is inserted into the hole to fix it.

[0044] 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 and the core pin 62. Next, the filled material is cooled and hardened. After the material has hardened, the mold and structure 6 are removed. In this way, the ferrule 3 is formed.

[0045] When the material of the ferrule 3 is filled into the mold, the area where the main body 61 and the core pin 62 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 61 and the core pin 62 were located is formed as a hollow area in the ferrule 3. The area where the main body 61 was located corresponds to the internal space 33, and the area where the core pin 62 was located corresponds to the hole 41 and the groove 32.

[0046] In the optical connector 1 and the ferrule 3, the fiber hole 31 is a hole into which the ends 21a of multiple glass fibers 21 aligned in the Y-axis direction can be inserted, and the width W1 of the fiber hole 31 along the Y-axis direction is greater than the width W2 of the fiber hole 31 along the Z-axis direction. Conventional ferrules, in which one optical fiber is inserted into each of multiple independent (separate) hole portions, are manufactured by arranging multiple independent core pins in a ferrule mold and filling the mold with ferrule material (e.g., molten resin). However, for example, the narrower the spacing between the core pins used to form the ferrule holes, the less material is properly filled between the core pins, which can result in unintended regions of the ferrule that are not filled with material. In contrast, in the ferrule 3, the ends 21a of multiple glass fibers 21 are inserted into a single fiber hole 31 that has a wide width W1 in the Y-axis direction, along which the ends 21a of the glass fibers 21 are aligned. The fiber hole 31 can be formed, for example, using a single member 63 formed by connecting multiple core pins 62. Therefore, during the manufacturing process of the ferrule 3, the amount of material of the ferrule 3 that needs to be filled between the core pins 62 is reduced. This reduces the possibility that unintended areas of the ferrule 3 that are not filled with material (for example, air traps or weld lines) will occur in the portions that form the fiber holes 31, and makes it possible to form the fiber holes 31 in the desired positions and shapes. Therefore, with this optical connector 1 and ferrule 3, it is possible to prevent degradation of optical characteristics.

[0047] Each fiber hole 31 extends along the X-axis direction and has a plurality of hole portions 41 into which the ends 21a of the corresponding glass fibers 21 can be inserted. The plurality of hole portions 41 are aligned in the Y-axis direction. Adjacent hole portions 41 are connected to each other in the Y-axis direction. This makes it possible to prevent the ends 21a of the plurality of glass fibers 21 inserted into the fiber holes 31 from shifting in position.

[0048] The pitch P of the plurality of holes 41 in the Y-axis direction may be 110 μm or more and 140 μm or less. In this case, it is possible to reduce the size of the ferrule 3. Furthermore, since more holes 41 can be formed in the ferrule 3, it is possible to increase the number of glass fibers 21 inserted into the ferrule 3, thereby improving the optical characteristics.

[0049] The ferrule 3 has a plurality of grooves 32 each extending along the X-axis direction. The grooves 32 are located closer to the rear end face 3b in the X-axis direction than the fiber holes 31. This allows the ends 21a of the glass fibers 21 to be easily inserted into the fiber holes 31 using the grooves 32.

[0050] The ferrule 3 has an internal space 33 that opens at the rear end face 3b and is connected to the fiber hole 31. This allows the internal space 33 to accommodate the ends 21a of the multiple glass fibers 21.

[0051] In the ribbon fiber 2, the coating layer 22 collectively coats a plurality of glass fibers 21, and the ends 21a of adjacent glass fibers 21 are in contact with each other. This prevents the ends 21a of the glass fibers 21 from shifting in position when the ends 21a are inserted into the fiber holes 31 of the ferrule 3. Therefore, the ribbon fiber 2 can prevent degradation of optical properties. Furthermore, compared to when each glass fiber is individually coated with an independent coating layer, the width of the ribbon fiber 2 can be made smaller, and the ferrule 3 into which the ribbon fiber 2 is inserted can be made smaller.

[0052] 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.

[0053] The pitch P of the holes 41 may be smaller than 110 μm or larger than 140 μm. When viewed from the X-axis direction, the inner surface 41a of the hole 41 may extend along a shape other than a circle (for example, an ellipse, a polygon, etc.). The fiber holes 31 may be formed so that the width of the opening of the fiber hole 31 in the front end face 3a along the Z-axis direction is constant. As an example, the opening of the fiber hole 31 in the front end face 3a may have a rectangular shape with long sides along the Y-axis direction.

[0054] Each hole 41 may have multiple portions of different sizes in a cross-sectional view perpendicular to the X-axis direction. For example, each hole 41 may have a first hole opening to the front end face 3a, a second hole located closer to the rear end face 3b than the first hole and having a diameter larger than that of the first hole, and a tapered portion located between the first and second holes and having a diameter increasing from the front end face 3a to the rear end face 3b. In this case, one end of the second hole may be connected to the first hole via the tapered portion, and the other end of the second hole may be connected to the groove 32. The ferrule 3 does not necessarily have to have the groove 32.

[0055] Adjacent glass fibers 21 do not need to be in contact with each other over the entire length of the glass fibers 21, and only the ends 21a of the glass fibers 21 need to be in contact with each other. Specifically, the portions of each glass fiber 21 other than the ends 21a are covered with a coating layer that individually (one by one) covers each glass fiber 21, and do not need to be in contact with adjacent glass fibers 21. In this case, the coating layer that individually covers the ends 21a of the glass fibers 21 may be removed, and the ends 21a of adjacent glass fibers 21 may be collectively covered with the coating layer 22. [Explanation of symbols]

[0056] 1...Optical connector 2... Ribbon fiber 3...Ferrule 3a...front end surface 3b…Rear end surface 3c,3d…side 3e, 3f...Main surface 6...Structure 21...Glass fiber 21a...end 22…Covering layer 23...Core 24...Clad 31...Fiber hole 32...Groove 32a...Inside 33...Interior space 34...Guide hole 35...Window section 41...hole 41a...Inside 42...Connection part 61...Main body 62...Core pin A1…First area A2…Second area

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 to the front end surface and into which ends of a plurality of glass fibers aligned in a second direction intersecting the first direction can be inserted, a width of the fiber hole along the second direction is larger than a width of the fiber hole along a third direction intersecting the first direction and the second direction; Ferrule.

2. the fiber holes each extend along the first direction and have a plurality of hole portions into which ends of corresponding glass fibers among the plurality of glass fibers can be inserted; the plurality of holes are aligned in the second direction, Adjacent holes among the plurality of holes are connected to each other in the second direction.

2. The ferrule of claim 1.

3. The pitch of the plurality of holes in the second direction is 110 μm or more and 140 μm or less.

3. The ferrule according to claim 2.

4. further comprising a plurality of grooves each extending along the first direction; the plurality of grooves are located closer to the rear end face than the fiber holes in the first direction; The ferrule according to claim 1 or 2.

5. an internal space that opens to the rear end surface and communicates with the fiber hole; The ferrule according to claim 1 or 2.

6. a ribbon fiber having a plurality of glass fibers each including a core and a cladding, and a coating layer that collectively coats the plurality of glass fibers; a ferrule having a front end surface, a rear end surface located on the opposite side of the front end surface in a first direction, and a fiber hole opening in the front end surface, a width of the fiber hole along a second direction intersecting the first direction is larger than a width of the fiber hole along a third direction intersecting the first direction and the second direction; the ends of the plurality of glass fibers are aligned in the second direction and inserted into the fiber holes in a state where they are exposed from the coating layer; Ends of adjacent glass fibers among the plurality of glass fibers are in contact with each other. Optical connector.

7. the ferrule further has an internal space that opens to the rear end surface and communicates with the fiber hole; The portions of the plurality of glass fibers covered with the coating layer are accommodated in the internal space.

7. The optical connector according to claim 6.

8. a plurality of glass fibers each including a core and a cladding; a coating layer that collectively coats the plurality of glass fibers, The ends of the plurality of glass fibers are aligned in a predetermined direction, Ends of adjacent glass fibers among the plurality of glass fibers are in contact with each other. Ribbon fiber.

Images