Optical connecting part

Abstract

To provide an optical connection component capable of appropriately transmitting an optical signal.SOLUTION: The optical connection component includes a plurality of optical fibers, a boot having a first through-hole into which the plurality of optical fibers are inserted, a support member that accommodates the boot, and a positioning member having a plurality of holes into which end portions of the plurality of optical fibers exposed from the boot are respectively inserted. The thermal expansion coefficient of the positioning member is 1 * 10-6 / K or more and 1 * 10-5 / K or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to optical connecting components. [Background technology]

[0002] Optical connecting components including a plurality of optical fibers and a holding member that holds the ends of the plurality of optical fibers are known (for example, Patent Documents 1 and 2). In such optical connecting components, the holding member is fixed to a substrate such as a silicon photonic integrated circuit (Si-PIC) substrate with an adhesive. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 5,619,604 [Patent Document 2] International Publication No. 2020 / 027125 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when heat is applied to the optical connecting component and the substrate during the process of fixing the holding member to the substrate, the optical connecting component may peel off from the substrate due to the difference in thermal expansion coefficients between the holding member and the substrate. Furthermore, optical connecting components are sometimes used with optical fibers bent to reduce their height, and bending can cause damage (breakage) to the optical fiber. Such peeling of the optical connecting component and damage to the optical fiber may prevent proper transmission of optical signals.

[0005] An object of the present disclosure is to provide an optical connecting part that can appropriately transmit an optical signal. [Means for solving the problem]

[0006] An optical connecting part according to an embodiment of the present disclosure includes a plurality of optical fibers, a boot having first through holes into which the plurality of optical fibers are inserted, a support member that houses the boot, and a positioning member having a plurality of holes into which the ends of the plurality of optical fibers exposed from the boot are inserted, respectively. The thermal expansion coefficient of the positioning member is 1×10 -6 / K or more 1×10 -5 / K or less. [Effects of the Invention]

[0007] According to the present disclosure, an optical connecting part capable of appropriately transmitting an optical signal is provided. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an optical connecting part according to one embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the optical connecting part taken along line II-II shown in FIG. [Figure 3] FIG. 3 is an enlarged view of a cross section of the optical connecting part shown in FIG. [Figure 4] FIG. 4 is a diagram showing the optical connecting part fixed to the substrate. [Figure 5] FIG. 5 is a view showing the boot shown in FIG. [Figure 6] FIG. 6 is a view showing the boot shown in FIG. [Figure 7] FIG. 7 is a view showing the positioning member 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.

[0010] [Description of the embodiments of the present disclosure] First, the contents of the embodiments of the present disclosure will be listed and described.

[0011] (1) An optical connecting component according to the present disclosure includes a plurality of optical fibers, a boot having first through holes into which the plurality of optical fibers are inserted, a support member that houses the boot, and a positioning member having a plurality of holes into which the ends of the plurality of optical fibers exposed from the boot are inserted, the positioning member having a thermal expansion coefficient of 1×10 -6 / K or more 1×10 -5 / K or less.

[0012] This optical connecting part is provided with a boot having a first through hole into which a plurality of optical fibers are inserted. As a result, the boot protects the optical fibers and prevents excessive bending of the optical fibers, making it difficult for damage (disconnection) to occur to the optical fibers. Also, in this optical connecting part, the thermal expansion coefficient of the positioning member is 1×10 -6 / K or more 1×10 -5 / K or less. Therefore, it is possible to reduce the difference between the thermal expansion coefficient of the positioning member and the base material (e.g., silicon) of a silicon photonic integrated circuit (Si-PIC) substrate or the like to which the optical connecting component is fixed. This makes it possible to prevent the optical connecting component from peeling off from the substrate due to the difference in the thermal expansion coefficients of the positioning member and the substrate when heat is applied in the process of fixing the positioning member to the substrate. Therefore, the optical connecting component allows for proper transmission of optical signals.

[0013] (2) The optical connecting part of (1) above may further include a first adhesive disposed in the plurality of holes and fixing the ends of the plurality of optical fibers to the positioning member. In this case, displacement of the ends of the plurality of optical fibers is prevented, and optical signals can be transmitted more appropriately.

[0014] (3) In the optical connecting part of (2) above, the first adhesive may be an ultraviolet-curing adhesive, and the positioning member may be made of a material that transmits ultraviolet light. In this case, ultraviolet light can be irradiated onto the first adhesive through the positioning member, so that the optical fiber can be efficiently fixed to the positioning member (the first adhesive can be cured). Also, even when the optical connecting part is fixed to another member (e.g., a substrate) with an ultraviolet-curing adhesive, ultraviolet light can be irradiated onto the adhesive through the positioning member, so that the optical connecting part can be efficiently fixed to the other member.

[0015] (4) In the optical connecting part of (2) or (3) above, the hardness of the first adhesive may be 80 or more. In this case, the optical fiber can be firmly fixed to the positioning member, and therefore, the optical fiber can be prevented from falling off the positioning member.

[0016] (5) In the optical connecting component of any one of (1) to (4), the positioning member has a first main surface on which the tip faces of the optical fibers are exposed and a second main surface located on the opposite side to the first main surface in a first direction in which the ends of the optical fibers extend, and each of the plurality of holes may be open in the first main surface and the second main surface, and the openings of the plurality of holes in the second main surface may be larger than the openings of the plurality of holes in the first main surface. In this case, the optical fibers can be easily inserted into the holes.

[0017] (6) In the optical connecting component of any one of (1) to (5), the boot may have a first end face and a second end face located on the opposite side to the first end face in a first direction in which the ends of the optical fibers extend, and the first through hole may be open at the first end face and the second end face. In this case, the optical fiber can be easily inserted into the first through hole.

[0018] (7) In the optical connecting part of (6) above, the outer edge of the first end face may be smaller than the outer edge of the second end face when viewed along the first direction. In this case, for example, if the support member has a tubular portion, the boot can be easily accommodated in the tubular portion of the support member.

[0019] (8) In the optical connecting component of (6) or (7), the support member may have a wall portion having a first surface and a second surface located on the opposite side of the first surface in the first direction, and a tubular portion formed on the second surface, the wall portion having second through holes into which the optical fibers are inserted, and the boot may be housed in the tubular portion so that the first end face faces the second surface. In this case, the boot can be appropriately protected by the wall portion and the tubular portion located so as to surround the boot, and the optical fibers can be exposed to the outside of the support member through the second through holes in the wall portion.

[0020] (9) The optical connecting part of (8) may further include a second adhesive for fixing the optical fibers to the support member, the boot may be housed in the tubular part so as to form a space between the first end face and the second surface, and the second adhesive may be disposed across the second through hole and the space. In this case, the second adhesive prevents the optical fibers from shifting, allowing for more appropriate transmission of optical signals.

[0021] (10) In the optical connecting component of (8) or (9), the second through hole may be open on the first surface and the second surface, and the opening of the second through hole on the second surface may be larger than the opening of the second through hole on the first surface. In this case, the optical fiber can be easily inserted into the second through hole.

[0022] (11) In any of the optical connecting components (8) to (10) above, the volume fraction of the boot occupying the internal space of the support member defined by the second surface and the inner surface of the tubular portion may be 50% or more and 90% or less. If too much second adhesive is placed in the space between the first end face and the second surface, the second adhesive may shrink when hardened, causing stress that may cause deformation or damage to the optical connecting component. In the optical connecting component, the volume fraction of the boot is 50% or more, making it possible to prevent these problems caused by an excess of second adhesive. Furthermore, in the optical connecting component, the volume fraction of the boot is 90% or less, making it possible to maintain a sufficient amount of second adhesive filling the space between the first end face and the second surface.

[0023] (12) In the optical connecting component of any one of (8) to (11) above, the tubular portion may have a third end face located on the opposite side of the wall portion in the first direction, the third end face may extend in an annular shape to surround the boot when viewed along the first direction, and the shape of the outer edge of the second end face may match the shape of the inner edge of the third end face when viewed along the first direction. In this case, it is possible to prevent the boot from falling off the support member.

[0024] (13) In any one of the optical connecting components (1) to (12), the flexural modulus of the boot may be lower than the flexural modulus of the support member, which further prevents damage to the optical fiber.

[0025] (14) In the optical connecting component of any one of (1) to (13) above, the first through hole may extend along a first direction, which is a direction in which the ends of the plurality of optical fibers extend, and the width of the first through hole along a second direction intersecting the first direction may be larger than the width of the first through hole along a third direction intersecting the first and second directions. In this case, a row including a plurality of optical fibers aligned in the second direction (e.g., a ribbon fiber cable) can be easily inserted into the first through hole. In other words, the plurality of optical fibers can be inserted into the first through hole in tape units, which simplifies the assembly work of the optical connecting component.

[0026] (15) In the optical connecting component of (14), the boot may have a plurality of first through holes, each of which is a first through hole, and the plurality of first through holes may be aligned in the third direction. In this case, the plurality of optical fibers can be aligned in an appropriate order in the third direction. For example, by inserting the plurality of optical fibers into the plurality of first through holes aligned in the third direction, it is less likely that the plurality of optical fibers will be misaligned or mixed up in the third direction, and each optical fiber can be aligned in an appropriate position.

[0027] [Details of the embodiments of the present disclosure] Specific examples of optical connecting components 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 duplicate explanations 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.

[0028] The configuration of an optical connecting part 100 according to one embodiment will be described with reference to FIGS. 1 to 4. FIG. 1 is a perspective view showing the optical connecting part 100. FIG. 2 is a cross-sectional view of the optical connecting part 100 taken along line II-II in FIG. 1. FIG. 3 is an enlarged view of the cross-section of the optical connecting part 100 shown in FIG. 2. FIG. 4 is a view showing the optical connecting part 100 fixed to a substrate 200. The optical connecting part 100 includes a plurality of optical fibers 1, a boot 2, a support member 3, and a positioning member 4. Hereinafter, the direction in which the ends 13 of the plurality of optical fibers 1 extend is referred to as the X-axis direction (first direction), a direction intersecting the X-axis direction is referred to as the Y-axis direction (second direction), and a direction intersecting the X-axis and Y-axis directions is referred to as the Z-axis direction (third direction). In this example, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to one another.

[0029] The multiple optical fibers 1 are arranged in a row. The multiple optical fibers 1 constitute multiple ribbon fiber cables (tape core wires) 10. In this example, the optical connecting part 100 includes 24 optical fibers 1. Eight optical fibers 1 constitute one ribbon fiber cable 10. That is, the optical connecting part 100 includes three ribbon fiber cables 10. The ends of the multiple ribbon fiber cables 10 are arranged side by side in the Z-axis direction. The ends 13 of the multiple optical fibers 1 included in each ribbon fiber cable 10 are arranged side by side in the Y-axis direction. The ends 13 of each optical fiber 1 extend along the X-axis direction.

[0030] Each optical fiber 1 has a core and a cladding surrounding the core. The cladding has a refractive index different from that of the core. The ribbon fiber cable 10 has a coating 11 that collectively covers the multiple optical fibers 1. Each optical fiber 1 includes a portion covered with the coating 11 and a portion not covered with the coating (where the coating 11 has been removed). The portion not covered with the coating 11 is located closer to the tip face of each optical fiber 1 than the portion covered with the coating 11.

[0031] The boot 2 is a member that protects a plurality of optical fibers 1. Here, a detailed configuration of the boot 2 will be described with reference to FIGS. 5 and 6. FIG. 5 is a view of the boot 2 as viewed along the X-axis direction. FIG. 6 is a view of the boot 2 as viewed along the Z-axis direction. The boot 2 has a substantially rectangular parallelepiped outer shape. The boot 2 has an end face (first end face) 21, an end face (second end face) 22, a surface 23, a surface 24, a surface 25, and a surface 26. The end face 22 is located on the opposite side to the end face 21 in the X-axis direction. The end faces 21 and 22 extend along the Y-axis direction and the Z-axis direction, respectively. The surface 24 is located on the opposite side to the surface 23 in the Y-axis direction. The surface 26 is located on the opposite side to the surface 25 in the Z-axis direction.

[0032] The boot 2 has a tapered shape that narrows as it approaches the end face 21 from the end face 22. Specifically, the surface 23 includes a portion 23a and a portion 23b that is located closer to the end face 22 than the portion 23a. The surface 24 includes a portion 24a and a portion 24b that is located closer to the end face 22 than the portion 24a. The portions 23a and 24a are inclined with respect to the X-axis direction so as to approach each other in the Y-axis direction as they approach the end face 21 from the end face 22. The portions 23b and 24b extend parallel to each other along the X-axis and Z-axis directions.

[0033] Surface 25 includes portion 25a and portion 25b, which is located closer to end face 22 than portion 25a. Surface 26 includes portion 26a and portion 26b, which is located closer to end face 22 than portion 26a. Portions 25a and 26a are inclined with respect to the X-axis direction so as to approach each other in the Z-axis direction as they approach from end face 22 toward end face 21. Portions 25b and 26b extend parallel to each other along the X-axis and Y-axis directions. As shown in FIG. 5 , when viewed along the X-axis direction, outer edge 21e of end face 21 is smaller than outer edge 22e of end face 22. When viewed along the X-axis direction, outer edge 21e is located inside outer edge 22e.

[0034] The boot 2 has a plurality of through holes (first through holes) 27. In this example, three through holes 27 are formed in the boot 2. The plurality of through holes 27 are aligned in the Z-axis direction. Each through hole 27 extends along the X-axis direction. Each through hole 27 opens at the end face 21 and the end face 22. Both ends of each through hole 27 in the X-axis direction are connected to the corresponding one of the end faces 21 and 22. In this example, when viewed along the X-axis direction, the through holes 27 (the inner surface 2a of the boot 2 defining each through hole 27) have a rectangular shape with long sides extending along the Y-axis direction. As shown in FIG. 5 , the width W1 of the through hole 27 along the Y-axis direction is smaller than the width W2 of the through hole 27 along the Z-axis direction. A plurality of optical fibers 1 (corresponding ribbon fiber cables 10) are inserted into each through hole 27.

[0035] The boot 2 is formed of a resin material, for example, a mixture of polyphenylene ether and hydrogenated styrene-based thermoplastic elastomer (SEBS). The material of the boot 2 may be, for example, FLEX NORYL™ Resin WCP921 from SABIC. The flexural modulus of the boot 2 is lower than that of the support member 3, which will be described later. In other words, the boot 2 is more flexible than the support member 3. The flexural modulus of the boot 2 may be, for example, 150 MPa to 200 MPa, 100 MPa to 250 MPa, or 180 MPa. The flexural modulus of the boot 2 is measured according to the ASTM D790 standard. The measurement is performed by placing the object to be measured on two supports and applying a load to the center. The stress and strain that occur as the object bends while increasing the load are measured. From these data, the flexural modulus is calculated. The crosshead (moving part of the measuring machine) movement speed (speed at which the measuring machine bends the object) during measurement is 12.5 mm / min. The length of the support span (distance between supports) used during measurement is 100 mm.

[0036] The support member 3 is a member that houses the boot 2. The support member 3 has a wall portion 31 and a tubular portion 35. The wall portion 31 is a plate-shaped member that extends along the Y-axis direction and the Z-axis direction. The wall portion 31 has a surface 32 and a surface 33. The surfaces 32 and 33 extend along the Y-axis direction and the Z-axis direction. The surface 33 is located on the opposite side of the surface 32 in the X-axis direction.

[0037] The wall portion 31 has a plurality of through holes (second through holes) 34. In this example, 24 through holes 34 are formed in the wall portion 31. Eight through holes 34 are aligned along the Y-axis direction, and three through holes 34 are aligned along the Z-axis direction. Three rows, each including eight through holes 34 aligned along the Y-axis direction, are aligned along the Z-axis direction. Each through hole 34 penetrates the wall portion 31 in the X-axis direction. Each through hole 34 opens in the surface 32 and the surface 33. Both ends of each through hole 34 in the X-axis direction are connected to the corresponding surface of the surface 32 or the surface 33. In this example, when viewed along the X-axis direction, the through holes 34 (the inner surface 31a of the wall portion 31 defining each through hole 34) have a circular shape. The difference obtained by subtracting the diameter of the optical fiber 1 from the diameter of each through hole 34 may be, for example, 2 μm or less.

[0038] As shown in FIG. 3, the through hole 34 (inner surface 31a) includes a tapered portion 34a. In the tapered portion 34a, the diameter of the through hole 34 decreases from the surface 33 toward the surface 32. The tapered portion 34a is connected to the surface 33. An opening 33e of the through hole 34 on the surface 33 is larger than an opening 32e of the through hole 34 on the surface 32. When viewed along the X-axis direction, each through hole 34 overlaps with a corresponding through hole 27. Ends 13 of the multiple optical fibers 1 exposed from the boot 2 are inserted into the multiple through holes 34, respectively. A portion of the optical fiber 1 from which the coating 11 has been removed is inserted into each through hole 34.

[0039] The tubular portion 35 is formed on the surface 33 of the wall portion 31. The tubular portion 35 is formed integrally with, i.e., connected to, the wall portion 31. The tubular portion 35 extends continuously along the outer edge of the surface 33 so that a space (internal space) S1 is formed inside the tubular portion 35. The tubular portion 35 has an end face (third end face) 36 located on the opposite side to the wall portion 31 in the X-axis direction. When viewed along the X-axis direction, the end face 36 extends in an annular shape so as to surround the boot 2.

[0040] The support member 3 is formed of a resin material such as liquid crystal polymer (LCP). The material of the support member 3 may be, for example, LAPEROS LCP E130i by POLYPLASTICS. The flexural modulus of the support member 3 is higher than that of the boot 2. The flexural modulus of the support member 3 may be, for example, 12,000 MPa or more and 18,000 MPa or less, or 10,000 MPa or more and 20,000 MPa or less. The flexural modulus of the support member 3 is measured in accordance with the ISO 178 standard. When the flexural moduli of the boot 2 and the flexural moduli of the support member 3 are compared, these flexural moduli are measured using a common measurement method (measurement conditions). The standard to which the measurement method conforms may be adopted from, for example, either the ASTM D790 standard or the ISO 178 standard.

[0041] The boot 2 is accommodated in the space S1. The space S1 is defined by the surface 33 of the wall portion 31 and the inner surface 37 of the tubular portion 35. The boot 2 is inserted into the space S1 from an opening in the end face 36 of the tubular portion 35. The boot 2 is accommodated in the space S1 so that the end face 21 faces the surface 33. The boot 2 is accommodated in the tubular portion 35 so that a space S2 (gap) is formed between the end face 21 and the surface 33. The volume ratio of the boot 2 to the space S1 may be 50% or more and 90% or less, 60% or more and 80% or less, or 72%. The volume of the boot 2 includes the volume inside the through hole 27.

[0042] In this example, the boot 2 is accommodated in the space S1 so that the end face 22 is flush with the end face 36, i.e., so that they are even and have no steps (so that their positions in the X-axis direction are the same). When viewed along the X-axis direction, the shape of the outer edge 22e of the end face 22 matches the shape of the inner edge 36e of the end face 36. The shape of the outer edge 22e matching the shape of the inner edge 36e means that no gap is formed between the inner edge 36e and the outer edge 22e. The portions 23a, 24a, 25a, and 26a do not contact the inner surface 37 of the tubular portion 35 and are separated from the inner surface 37. A space (gap) S3 is formed between the portions 23a, 24a, 25a, and 26a and the inner surface 37. The portions 23b, 24b, 25b, and 26b contact the inner surface 37 of the tubular portion 35.

[0043] The positioning member 4 is a member that holds the end portions 13 of the multiple optical fibers 1 and determines the positions of the end portions 13. Here, a detailed configuration of the positioning member 4 will be described with reference to FIG. 7 as well. FIG. 7 is a view of the positioning member 4 as viewed along the X-axis direction. The positioning member 4 has a substantially rectangular plate shape. The thickness direction of the positioning member 4 is along the X-axis direction, the long side direction is along the Y-axis direction, and the short side direction is along the Z-axis direction. The positioning member 4 has a main surface (first main surface) 41, a main surface (second main surface) 42, a surface 43, a surface 44, a surface 45, and a surface 46. The main surface 42 is located on the opposite side to the main surface 41 in the X-axis direction. The main surfaces 41 and 42 extend along the Y-axis direction and the Z-axis direction, respectively. The surface 44 is located on the opposite side to the surface 43 in the Y-axis direction. The surfaces 43 and 44 extend along the X-axis direction and the Z-axis direction, respectively. The surface 46 is located on the opposite side to the surface 45 in the Z-axis direction. The surface 45 and the surface 46 extend along the X-axis direction and the Y-axis direction, respectively.

[0044] The positioning member 4 has a plurality of holes 47. In this example, 24 holes 47 are formed in the positioning member 4. Eight holes 47 are aligned along the Y-axis direction, and three holes 47 are aligned along the Z-axis direction. Three rows, each including eight holes 47 aligned along the Y-axis direction, are aligned along the Z-axis direction. Each hole 47 penetrates the positioning member 4 in the X-axis direction. Each hole 47 opens in the main surface 41 and the main surface 42. Both ends of each hole 47 in the X-axis direction are connected to the corresponding one of the main surfaces 41 and 42. In this example, when viewed along the X-axis direction, the holes 47 (the inner surface 4a of the positioning member 4 that defines each hole 47) have a circular shape. The difference between the diameter of each hole 47 and the diameter of the optical fiber 1 may be, for example, 2 μm or less.

[0045] As shown in FIG. 3 , the hole 47 (inner surface 4a) includes a tapered portion 47a. In the tapered portion 47a, the diameter of the hole 47 decreases from the main surface 42 toward the main surface 41. The tapered portion 47a is connected to the main surface 42. The opening 42e of the hole 47 in the main surface 42 is larger than the opening 41e of the hole 47 in the main surface 41. When viewed along the X-axis direction, each hole 47 overlaps with the corresponding through hole 27 and through hole 34. Ends 13 of the multiple optical fibers 1 exposed from the boot 2 are inserted into the multiple holes 47, respectively. Portions of the optical fibers 1 from which the coating 11 has been removed are inserted into each hole 47. Tip surfaces 12 of the multiple optical fibers 1 are exposed from the main surface 41 to the outside of the positioning member 4.

[0046] The positioning member 4 is made of a glass material such as borosilicate glass. The material of the positioning member 4 may be, for example, BOROFLOAT glass by SCHOTT. When the positioning member 4 is made of a hard material such as glass, the positioning accuracy of the optical fiber 1 can be improved. In this example, the positioning member 4 is made of a material that transmits ultraviolet light. The ultraviolet transmittance of the positioning member 4 for ultraviolet light with a wavelength of 315 nm or more and 400 nm or less may be 70% or more. The thermal expansion coefficient of the positioning member 4 is 1×10 -6 / K or more 1×10-5 / K or less. The thermal expansion coefficient of the positioning member 4 is 2×10 -6 / K or more 5×10 -6 / K or less, or 3.25 × 10 -6 / K. The thermal expansion coefficient of the positioning member 4 is the average thermal expansion coefficient of the positioning member 4 at a temperature of 20° C. or higher and 300° C. or lower. The thermal expansion coefficient of the positioning member 4 is measured by the method of JIS R 3102, for example.

[0047] The optical connecting part 100 includes an adhesive 5. The adhesive 5 is arranged in the space S2, the space S3, the plurality of through holes 27, the plurality of through holes 34, between the surface 32 and the main surface 42, and across the plurality of holes 47. The portions of the adhesive 5 arranged across the space S2 and the plurality of through holes 34 (second adhesive) fix the plurality of optical fibers 1 to the support member 3. The portions of the adhesive 5 arranged in the space S3 fix the boot 2 to the support member 3. The portions of the adhesive 5 arranged in the plurality of through holes 27 fix the plurality of optical fibers 1 to the boot 2. The portions of the adhesive 5 arranged between the surface 32 and the main surface 42 fix the support member 3 to the positioning member 4. The portions of the adhesive 5 arranged in the plurality of holes 47 (first adhesive) fix the ends 13 of the plurality of optical fibers 1 to the positioning member 4.

[0048] For example, the adhesive 5 may be injected into the interior (space S2) of the support member 3 and then permeate into the space S3, the plurality of through holes 27, the plurality of through holes 34, the gap between the surface 32 and the main surface 42, and the plurality of holes 47. The adhesive 5 does not reach the openings 28 of the plurality of through holes 27 in the end face 22. Therefore, even if the portion of the ribbon fiber cable 10 exposed outside the boot 2 from the openings 28 is bent, the bent portion does not come into contact with the adhesive 5 at the openings 28. This makes it possible to prevent the bent portion of the ribbon fiber cable 10 from coming into contact with the adhesive 5 and being damaged when the hardened adhesive 5 is harder than the boot 2 (when the flexural modulus or Young's modulus is higher).

[0049] The material of the adhesive 5 may be a resin such as epoxy. The adhesive 5 may be, for example, EPO-TEK 353ND or NTT-AT EH4197. The hardness of the adhesive 5 may be 80 or more. The hardness of the adhesive 5 refers to the hardness of the adhesive 5 after it has hardened. The hardness of the adhesive 5 is measured using a Type D durometer. The adhesive 5 is an ultraviolet-curable adhesive. The adhesive 5 is a thermosetting adhesive. The adhesive 5 may be hardened in the following manner. That is, since the positioning member 4 is made of a material that transmits ultraviolet light, ultraviolet light can be irradiated through the positioning member 4 onto the portions of the adhesive 5 positioned in the holes 47. Therefore, the portions of the adhesive 5 positioned in the multiple holes 47 may first be hardened (temporarily fixed) by ultraviolet light irradiation through the positioning member 4. Then, the entire adhesive 5, including the remaining portions, may be heated to be fully hardened (fully hardened).

[0050] As shown in FIG. 4, the optical connecting part 100 is fixed to a substrate 200. In this example, the substrate 200 is a silicon photonic integrated circuit (Si-PIC) substrate. The Si-PIC substrate is a substrate that uses silicon as the base material. Elements and circuits for processing optical signals are integrated on the substrate 200. With the optical connecting part 100 fixed to the substrate 200, the optical fiber 1 and the elements mounted on the substrate 200 are optically connected, and optical signals are transmitted between them.

[0051] The thermal expansion coefficient of the substrate 200 is 2×10 -6 / K or more 5×10 -6 / K or less. The thermal expansion coefficient of the substrate 200 is the average thermal expansion coefficient of the base material (silicon in this example) of the substrate 200 at temperatures between 20°C and 300°C. The thermal expansion coefficient of the substrate 200 is measured by a thermal dilatometer. As described above, the thermal expansion coefficient of the positioning member is 1×10 -6 / K or more 1×10 -5 / K or less. That is, the thermal expansion coefficient of the substrate 200 and the thermal expansion coefficient of the positioning member 4 are both approximately 10 -6 / K order, and the difference between the two is small.

[0052] The optical connecting part 100 is placed on the substrate 200 so that the main surface 41 of the positioning member 4 faces the main surface 200a of the substrate 200. An adhesive may be placed between the main surface 41 and the main surface 200a, and the optical connecting part 100 may be fixed to the substrate 200 by the adhesive. In the process of fixing the optical connecting part 100 (positioning member 4) to the substrate 200, a heat treatment may be performed on the optical connecting part 100 and the substrate 200. The optical connecting part 100 may be used with the plurality of optical fibers 1 (the plurality of ribbon fiber cables 10) bent. At this time, the ribbon fiber cables 10 may come into contact with the boot 2 (specifically, the inner surface 2a of the boot 2 that defines the through hole 27).

[0053] As described above, the optical connecting part 100 includes the boot 2 having the through holes 27 into which the plurality of optical fibers 1 are inserted. As a result, the boot 2 protects the optical fibers 1 and prevents excessive bending of the optical fibers 1, making it difficult for the optical fibers 1 to be damaged (broken). In addition, in this optical connecting part 100, the thermal expansion coefficient of the positioning member 4 is 1×10 -6 / K or more 1×10 -5 / K or less. Therefore, it is possible to reduce the difference in thermal expansion coefficient between the base material (silicon) of the silicon photonic integrated circuit (Si-PIC) substrate to which the optical connecting part 100 is fixed and the thermal expansion coefficient of the positioning member 4. This makes it possible to prevent the optical connecting part 100 from peeling off from the substrate 200 due to the difference in thermal expansion coefficient between the positioning member 4 and the substrate 200 when heat is applied in the process of fixing the positioning member 4 to the substrate 200. Therefore, the optical connecting part 100 can transmit optical signals appropriately.

[0054] The optical connecting part 100 is provided with adhesive 5 that is disposed in the plurality of holes 47 and fixes the ends 13 of the plurality of optical fibers 1 to the positioning member 4. This prevents the ends 13 of the plurality of optical fibers 1 from shifting in position, allowing for more appropriate transmission of optical signals.

[0055] The adhesive 5 is an ultraviolet-curing adhesive. The positioning member 4 is made of a material that transmits ultraviolet light. This allows ultraviolet light to be irradiated onto the adhesive 5 via the positioning member 4, making it possible to efficiently fix the optical fiber 1 to the positioning member 4 (hardening the adhesive 5). Also, even when the optical connecting part 100 is fixed to the substrate 200 with an ultraviolet-curing adhesive, ultraviolet light can be irradiated onto the adhesive disposed between the positioning member 4 and the substrate 200 via the positioning member 4, making it possible to efficiently fix the optical connecting part 100 to the substrate 200.

[0056] The hardness of the adhesive 5 is equal to or greater than 80. This allows the optical fiber 1 to be firmly fixed to the positioning member 4, thereby preventing the optical fiber 1 from falling off the positioning member 4.

[0057] The positioning member 4 has a main surface 41 on which the tip faces of the plurality of optical fibers 1 are exposed, and a main surface 42 located on the opposite side of the main surface 41 in the X-axis direction from the main surface 41. The plurality of holes 47 are each open on the main surface 41 and the main surface 42. Openings 42e of the plurality of holes 47 on the main surface 42 are larger than openings 41e of the plurality of holes 47 on the main surface 41. This allows the optical fibers 1 to be easily inserted into the holes 47.

[0058] The boot 2 has an end face 21 and an end face 22 located on the opposite side of the end face 21 in the X-axis direction. The through hole 27 is open at the end face 21 and the end face 22. This allows the optical fiber 1 to be easily inserted into the through hole 27.

[0059] When viewed along the X-axis direction, the outer edge 21e of the end face 21 is smaller than the outer edge 22e of the end face 22. This allows the boot 2 to be easily accommodated in the tubular portion 35 of the support member 3.

[0060] The support member 3 has a wall portion 31 having a surface 32 and a surface 33 located opposite to the surface 32 in the X-axis direction, and a tubular portion 35 formed on the surface 33. The wall portion 31 has through holes 34 into which a plurality of optical fibers 1 are inserted. The boot 2 is housed in the tubular portion 35 so that the end face 21 faces the surface 33. This allows the boot 2 to be appropriately protected by the wall portion 31 and the tubular portion 35 located so as to surround the boot 2, and also allows the optical fibers 1 to be exposed to the outside of the support member 3 from the through holes 34 of the wall portion 31.

[0061] The optical connecting part 100 includes an adhesive 5 that fixes a plurality of optical fibers 1 to a support member 3. The boot 2 is housed in a tubular portion 35 so that a space S2 is formed between the end face 21 and the surface 33. The adhesive 5 is disposed across the through hole 34 and the space S2. This prevents the optical fibers 1 from shifting in position, allowing for more appropriate transmission of optical signals.

[0062] The through hole 34 is open on the surface 32 and the surface 33, and the opening 33e of the through hole 34 on the surface 33 is larger than the opening 32e of the through hole 34 on the surface 32. This makes it possible to easily insert the optical fiber 1 into the through hole 34.

[0063] The volumetric ratio of the boot 2 occupying the space S1 of the support member 3 defined by the surface 33 and the inner surface of the tubular portion 35 is 50% or more and 90% or less. If too much adhesive 5 is placed in the space S2 between the end face 21 and the surface 33, the adhesive 5 may shrink when it hardens, causing stress that may cause deformation or damage to the optical connecting part 100. In the optical connecting part 100, the volumetric ratio of the boot 2 is 50% or more, so it is possible to prevent these problems caused by an excess of adhesive 5. Furthermore, in the optical connecting part 100, the volumetric ratio of the boot 2 is 90% or less, so it is possible to maintain a sufficient amount of adhesive 5 filled in the space S2.

[0064] The tubular portion 35 has an end face 36 located on the opposite side of the wall portion 31 in the X-axis direction. When viewed along the X-axis direction, the end face 36 extends in an annular shape so as to surround the boot 2. When viewed along the X-axis direction, the shape of the outer edge 22e of the end face 22 matches the shape of the inner edge 36e of the end face 36. This makes it possible to prevent the boot 2 from falling off the support member 3.

[0065] The flexural modulus of the boot 2 is lower than the flexural modulus of the support member 3. This makes it possible to further prevent the optical fiber 1 from being damaged.

[0066] The through hole 27 extends along the X-axis direction. The width W1 of the through hole 27 along the Y-axis direction is larger than the width W2 of the through hole 27 along the Z-axis direction. This allows a row including a plurality of optical fibers 1 aligned in the Y-axis direction (e.g., a ribbon fiber cable) to be easily inserted into the through hole 27. In other words, a plurality of optical fibers 1 can be inserted into the through hole 27 in tape units, which simplifies the assembly work of the optical connecting part 100.

[0067] The boot 2 has a plurality of through holes 27. The plurality of through holes 27 are aligned in the Z-axis direction. This allows the plurality of optical fibers 1 to be aligned in an appropriate order in the Z-axis direction. For example, by inserting the plurality of optical fibers 1 into the plurality of through holes 27 aligned in the Z-axis direction, it is less likely that the plurality of optical fibers 1 will be misaligned or mixed up in the Z-axis direction, and each optical fiber 1 can be aligned in an appropriate position.

[0068] 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.

[0069] The boot 2 does not have to have a tapered shape that narrows from the end face 22 toward the end face 21. The outer edge shape of the boot 2 in a cross section perpendicular to the Y-axis direction may be constant. When viewed along the X-axis direction, the shape of the outer edge 21e of the end face 21 may be the same as the shape of the outer edge 22e of the end face 22. When viewed along the X-axis direction, the outer edge 21e of the end face 21 may be larger than the outer edge 22e of the end face 22. When viewed along the X-axis direction, the shape of the outer edge 22e of the end face 22 does not have to match the shape of the inner edge 36e of the end face 36. A gap may be formed between the inner edge 36e and the outer edge 22e.

[0070] The end surface 22 does not have to be flush with the end surface 36, i.e., it does not have to be a smooth, even surface with no steps. The boot 2 may be accommodated in the space S1 so that the end surface 22 is located closer to the wall 31 than the end surface 36 (so that the entire boot 2 is located inside the space S1). The boot 2 may be accommodated in the space S1 so that the end surface 22 is located farther from the wall 31 than the end surface 36 (so that the end surface 22 of the boot 2 is located outside the space S1).

[0071] The space S2 does not have to be formed. That is, the boot 2 may be accommodated in the space S1 so that the end face 21 contacts the surface 33. The volume ratio of the boot 2 occupying the space S1 may be less than 50% or more than 90%.

[0072] The through hole 34 (inner surface 31a) may not include a tapered portion 34a. The diameter of the through hole 34 may be constant. The size of the opening 33e of the through hole 34 on the surface 33 may be the same as the size of the opening 32e of the through hole 34 on the surface 32. The size of the opening 33e may be smaller than the size of the opening 32e.

[0073] The positioning member 4 does not have to be made of a material that transmits ultraviolet light. The hole 47 (inner surface 4a) does not have to include the tapered portion 47a. The diameter of the hole 47 may be constant. The size of the opening 42e of the hole 47 in the main surface 42 may be the same as the size of the opening 41e of the hole 47 in the main surface 41. The opening 42e may be smaller than the opening 41e.

[0074] Of the adhesive 5, at least one of the portion arranged in the space S2, the portion arranged in the space S3, the portion arranged in the plurality of through holes 27, the portion arranged in the plurality of through holes 34, the portion arranged between the surface 32 and the main surface 42, and the portion arranged in the plurality of holes 47 may be omitted or may be separate from the other portions. For example, the portion of the adhesive 5 arranged in the plurality of holes 47 (first adhesive) may be separate from the portion of the adhesive 5 arranged across the space S2 and the plurality of through holes 34 (second adhesive).

[0075] The adhesive 5 does not have to be an ultraviolet-curing adhesive. The adhesive 5 does not have to be a thermosetting adhesive. The hardness of the adhesive 5 may be less than 80. The number of through holes 27 formed in the boot 2, the number of through holes 34 formed in the support member 3, and the number of holes 47 formed in the positioning member 4 are not limited. [Explanation of symbols]

[0076] 1...Optical fiber 2. Boots 3...Support member 4... Positioning member 5...Adhesive 10...Ribbon fiber cable 11...Covering 12…Tip surface 13...End 21...End face 21e...outer edge 22...End face 22e...outer edge 23…Surface 23a, 23b...part 24…Surface 24a, 24b...part 25…Surface 25a, 25b...part 26…Surface 26a, 26b...part 27...Through hole 28…Aperture 31...Wall part 32…Surface 32e…Aperture 33…Surface 33e…Aperture 34...Through hole 34a...Tapered part 35...Cylinder part 36…End face 36e...Common Marriage 37...Inner 41...Main surface 41e…Aperture 42...Main surface 42e…Aperture 43, 44, 45, 46…Surface 47…hole 47a...Tapered section 100...Optical connection parts 200...Substrate 200a…main surface S1, S2, S3…space W1, W2...Width

Claims

1. a plurality of optical fibers; a boot having a first through hole into which the plurality of optical fibers are inserted; a support member that houses the boot; a positioning member having a plurality of holes into which the ends of the plurality of optical fibers exposed from the boot are inserted, The thermal expansion coefficient of the positioning member is 1×10 －６ / K or more 1×10 －５ / K or less, Optical connection parts.

2. a first adhesive disposed in the plurality of holes and fixing the ends of the plurality of optical fibers to the positioning member; The optical connecting part according to claim 1 .

3. the first adhesive is an ultraviolet curing adhesive, The positioning member is formed of a material that transmits ultraviolet light. The optical connecting part according to claim 2 .

4. The hardness of the first adhesive is 80 or more. The optical connecting part according to claim 2 .

5. the positioning member has a first main surface to which tip surfaces of the plurality of optical fibers are exposed, and a second main surface located on the opposite side to the first main surface in a first direction which is a direction in which the ends of the plurality of optical fibers extend, each of the plurality of holes is open to the first main surface and the second main surface; the openings of the plurality of holes in the second main surface are larger than the openings of the plurality of holes in the first main surface; The optical connecting part according to any one of claims 1 to 3.

6. the boot has a first end face and a second end face located on the opposite side to the first end face in a first direction, which is a direction in which the ends of the plurality of optical fibers extend; the first through hole is open at the first end surface and the second end surface; The optical connecting part according to any one of claims 1 to 3.

7. When viewed along the first direction, an outer edge of the first end surface is smaller than an outer edge of the second end surface. The optical connecting part according to claim 6 .

8. the support member includes a wall portion having a first surface and a second surface located on the opposite side to the first surface in the first direction, and a tubular portion formed on the second surface; the wall portion has second through holes into which the plurality of optical fibers are inserted; The boot is accommodated in the tubular portion such that the first end surface faces the second surface. The optical connecting part according to claim 6 .

9. a second adhesive that fixes the plurality of optical fibers to the support member; the boot is accommodated in the tubular portion such that a space is formed between the first end surface and the second surface, the second adhesive is disposed across the second through hole and the space; The optical connecting part according to claim 8 .

10. the second through hole is open at the first surface and the second surface, an opening of the second through hole in the second surface is larger than an opening of the second through hole in the first surface; The optical connecting part according to claim 8 .

11. a volume ratio of the boot occupying an internal space of the support member defined by the second surface and the inner surface of the tubular portion is 50% or more and 90% or less; The optical connecting part according to claim 8 .

12. the cylindrical portion has a third end surface located on the opposite side to the wall portion in the first direction, the third end surface extends annularly so as to surround the boot when viewed along the first direction, When viewed along the first direction, the shape of an outer edge of the second end surface coincides with the shape of an inner edge of the third end surface. The optical connecting part according to claim 8 .

13. The flexural modulus of the boot is lower than the flexural modulus of the support member. The optical connecting part according to any one of claims 1 to 3.

14. the first through hole extends along a first direction in which the ends of the optical fibers extend, a width of the first through hole along a second direction intersecting the first direction is larger than a width of the first through hole along a third direction intersecting the first direction and the second direction; The optical connecting part according to any one of claims 1 to 3.

15. the boot has a plurality of first through holes, each of which is the first through hole; The plurality of first through holes are aligned in the third direction. The optical connecting part according to claim 14.

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