Optical connection structure

Abstract

To provide an optical connection structure which facilitates alignment work in optical connection between a core of an optical fiber and a core group.SOLUTION: An optical connection structure according to one embodiment includes a multi-core fiber array holding a multi-core fiber and a first alignment part, a single-core fiber array holding a plurality of single-core fibers and a second alignment part, and an optical waveguide substrate having a core group and an alignment core optically connected to each of the first alignment part and the second alignment part. The first alignment element has a core portion for guiding light. The area of the core part exposed to the end face of the first alignment component facing the optical waveguide substrate is larger than the area of the alignment core exposed to the end face of the optical waveguide substrate facing the multi-core fiber array.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an optical connection structure. [Background technology]

[0002] Patent Document 1 discloses an optical circuit component. The optical circuit component aligns and connects the input / output terminals of an optical waveguide substrate having a predetermined function and composed of at least three core groups to an optical fiber array component in which a plurality of optical fibers are arranged. The optical waveguide substrate has, in addition to the core groups having the predetermined function, independent optical waveguides that are not involved in the function. The optical circuit component aligns the optical waveguides with the optical fibers of the optical fiber array component corresponding to the optical waveguides, thereby connecting the optical waveguide substrate and the optical fiber array component. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 08-313744 Summary of the Invention [Problem to be solved by the invention]

[0004] As mentioned above, when aligning an optical fiber array in which a plurality of optical fibers are arranged, the alignment of the optical fibers may not be easy depending on the size of the optical fiber cores. When aligning at both the first end and the second end of the optical waveguide substrate, the alignment work may have to be continued until the optical fibers of the optical fiber array are optically connected to the core groups at both the first end and the second end of the optical waveguide substrate simultaneously. Therefore, there is room for improvement in the efficiency of the alignment work when optically connecting the cores of the optical fibers to the core groups.

[0005] An object of the present disclosure is to provide an optical connection structure that facilitates alignment work in optically connecting a core and a core group of an optical fiber. [Means for solving the problem]

[0006] The optical connection structure according to the present disclosure optically connects a multicore fiber having multiple cores to multiple single-core fibers. This optical connection structure includes: a multicore fiber array holding the multicore fiber and a first alignment component extending along the multicore fiber; a single-core fiber array holding multiple single-core fibers and a second alignment component extending along the single-core fibers; and an optical waveguide substrate having core groups optically connected to the multicore fiber and the multiple single-core fibers, respectively, and alignment cores optically connected to the first alignment component and the second alignment component, respectively. The first alignment component has a core portion that guides light. The area of ​​the core portion exposed at the end face of the first alignment component facing the optical waveguide substrate is larger than the area of ​​the alignment core exposed at the end face of the optical waveguide substrate facing the multicore fiber array. [Effects of the Invention]

[0007] According to the present disclosure, the alignment work for optically connecting the core and core group of an optical fiber becomes easier. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing an optical connection structure according to a first embodiment. [Figure 2] FIG. 1 is a perspective view showing an optical connection structure in which a multi-core fiber array, an optical waveguide substrate, and a single-core fiber array are separated from each other. [Figure 3] FIG. 2 is a plan view showing an optical connection structure. [Figure 4] FIG. 2 is a side view showing the optical connection structure. [Figure 5] FIG. 2 is a front view showing an end face of the multi-core fiber array. [Figure 6] FIG. 2 is a front view showing the end face of the single-core fiber array. [Figure 7] FIG. 2 is a front view showing a first end face of the optical waveguide substrate. [Figure 8] FIG. 4 is a front view showing a second end face of the optical waveguide substrate. [Figure 9] FIG. 10 is a plan view showing an optical connection structure according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiment of the present invention] First, embodiments of the optical connection structure according to the present disclosure will be listed and described. (1) The optical connection structure according to the present embodiments is an optical connection structure that optically connects a multicore fiber having multiple cores to multiple single-core fibers. This optical connection structure includes: a multicore fiber array that holds a multicore fiber and a first alignment component extending along the multicore fiber; a single-core fiber array that holds multiple single-core fibers and a second alignment component extending along the single-core fiber; and an optical waveguide substrate that has core groups optically connected to the multicore fiber and the multiple single-core fibers, respectively, and alignment cores optically connected to the first alignment component and the second alignment component, respectively. The first alignment component has a core portion that guides light. The area of ​​the core portion exposed at the end face of the first alignment component facing the optical waveguide substrate is larger than the area of ​​the alignment core exposed at the end face of the optical waveguide substrate facing the multicore fiber array.

[0010] In this optical connection structure, the area of ​​the core portion exposed on the end face of the first alignment component facing the optical waveguide substrate is larger than the area of ​​the alignment core exposed on the end face of the optical waveguide substrate facing the multicore fiber array. This allows the alignment light to be incident from the alignment core to the first alignment component without requiring excessively precise alignment work when irradiating the alignment light from the second alignment component toward the first alignment component. As a result, it becomes easier to detect the alignment light, facilitating the alignment work between the second alignment component and the alignment core. This facilitates the alignment work for optical connection between the cores of the multicore fiber and the multiple single-core fibers and the core group formed on the optical waveguide substrate.

[0011] (2) In the above (1), the multi-core fiber array may hold a plurality of first alignment components. The single-core fiber array may hold a plurality of second alignment components. The optical waveguide substrate may have a plurality of alignment cores. The arrangement interval of the plurality of first alignment components may match the arrangement interval of the plurality of alignment cores. In this case, it is possible to improve the accuracy of both the alignment between the first alignment components and the alignment cores and the alignment between the second alignment components and the alignment cores.

[0012] (3) In the above (1) or (2), the multicore fiber array may hold a plurality of first alignment components. The single-core fiber array may hold a plurality of second alignment components. The optical waveguide substrate may have a plurality of alignment cores. A multicore fiber may be arranged between a plurality of first alignment components. A plurality of single-core fibers may be arranged between a plurality of second alignment components. A core group may be arranged between a plurality of alignment cores. In this case, the plurality of first alignment components are arranged at positions sandwiching the multicore fiber, and the plurality of second alignment components are arranged at positions sandwiching the plurality of single-core fibers. The plurality of alignment cores are arranged at positions sandwiching the core group. This makes it possible to improve the positional accuracy of the multicore fiber, the optical waveguide substrate, and the plurality of single-core fibers when each first alignment component is aligned with each alignment core, and when each second alignment component is aligned with each alignment core.

[0013] (4) In any of the above (1) to (3), the first alignment component may include a multimode fiber. In this case, a multimode fiber having a core portion larger than the core diameter of a single-core fiber can be used for alignment.

[0014] (5) In any of (1) to (4) above, the optical waveguide substrate may have a marker that allows the position of the alignment core to be determined. In this case, the position of the alignment core on the optical waveguide substrate can be determined by looking at the marker. This makes it easier to align the alignment core with the first alignment component and the alignment core with the second alignment component.

[0015] [Details of the embodiment of the present invention] Specific examples of optical connection structures according to embodiments of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to the examples below, but is defined by the claims, and is intended to include all modifications within the scope equivalent to the claims. In the description of the drawings, identical or corresponding elements are given the same reference numerals, and redundant description will be omitted as appropriate. The drawings may be partially simplified or exaggerated for ease of understanding, and dimensional proportions and the like are not limited to those shown in the drawings.

[0016] (First embodiment) Fig. 1 is a perspective view showing an optical connection structure 1 according to a first embodiment. The optical connection structure 1 includes a multicore fiber array 10, a single-core fiber array 20, and an optical waveguide substrate 30. The optical connection structure 1 optically connects a multicore fiber 3 having a plurality of cores 3a (see Fig. 5) to a plurality of single-core fibers 4. In the optical connection structure 1, the multicore fiber array 10, the optical waveguide substrate 30, and the single-core fiber array 20 are arranged in this order.

[0017] In the optical connection structure 1, optical signals are distributed and aggregated by an optical waveguide substrate 30, which will be described in detail later. The optical connection structure 1 has a function as a FIFO (Fan-In / Fan-Out).

[0018] In the following description, the direction in which the multi-core fiber 3 and the single-core fiber 4 extend is referred to as a first direction D1, the direction in which the multiple single-core fibers 4 are arranged is referred to as a second direction D2, and the direction orthogonal to both the first direction D1 and the second direction D2 is referred to as a third direction D3. However, these directions are used for convenience of description and do not limit the arrangement positions or directions of objects.

[0019] The multicore fiber array 10 holds a multicore fiber 3 and a first alignment component 2. In this embodiment, the multicore fiber array 10 holds a multicore fiber 3 and a plurality of first alignment components 2. In one example, the multicore fiber array 10 holds one multicore fiber 3. In one example, the multicore fiber array 10 holds two first alignment components 2.

[0020] The first alignment component 2 extends along the multi-core fiber 3. The first alignment component 2 is a component for aligning the multi-core fiber 3 with a core group 32, which will be described later. The first alignment components 2 are lined up in the second direction D2. The multiple first alignment components 2 and the multi-core fiber 3 are lined up in the second direction D2. The multi-core fiber 3 is arranged between the multiple first alignment components 2. The multiple first alignment components 2 are arranged with the multi-core fiber 3 sandwiched between them. In one example, one multi-core fiber 3 is arranged between two first alignment components 2. The multiple first alignment components 2 are arranged with an interval d1 between them (see FIG. 5 ). The first alignment components 2 will be described in detail later.

[0021] The multicore fiber array 10 has a base 11 and a lid 12. The base 11 has a rectangular parallelepiped shape. The length of the base 11 in the first direction D1 is longer than the length of the base 11 in the second direction D2 and the length of the base 11 in the third direction D3. FIG. 2 is a perspective view showing the optical connection structure 1 in a state in which the multicore fiber array 10, the optical waveguide substrate 30, and the single-core fiber array 20 are separated from each other. As shown in FIG. 2, the base 11 has an end face 11a. The end face 11a is a face of the base 11 facing in the direction opposite to the first direction D1. The end face 11a faces the optical waveguide substrate 30. The end face 11a may be inclined with respect to the third direction D3 when viewed from the second direction D2.

[0022] The base 11 has an upper surface 11b. The upper surface 11b is the surface of the base 11 facing the third direction D3. The first alignment component 2 and the multi-core fiber 3 are placed on the upper surface 11b. The first alignment component 2 has, for example, a coating that protects the core portion 2a, which will be described later. The boundary between the portion where both the first alignment component 2 and the multi-core fiber 3 are coated and the portion where the coatings of both the first alignment component 2 and the multi-core fiber 3 have been removed is located on the upper surface 11b.

[0023] A protruding portion 11c protruding in the third direction D3 is formed in a portion of the base 11 closer to the optical waveguide substrate 30. The protruding portion 11c has a rectangular parallelepiped shape. A plurality of V-shaped grooves 11d are formed on the surface of the protruding portion 11c facing the third direction D3. In one example, three V-shaped grooves 11d are formed. The V-shaped grooves 11d extend along the first direction D1. The plurality of V-shaped grooves 11d are lined up along the second direction D2. A multicore fiber 3 is disposed in the central V-shaped groove 11d. First alignment components 2 are disposed in the V-shaped grooves 11d located on both sides of the central V-shaped groove 11d. The coatings of both the multicore fiber 3 and the first alignment component 2 placed in the V-shaped groove 11d have been removed.

[0024] FIG. 3 is a plan view showing the optical connection structure 1. FIG. 4 is a side view showing the optical connection structure 1. As shown in FIGS. 3 and 4, the lid 12 has a rectangular parallelepiped shape. The length of the lid 12 in the third direction D3 is smaller than the length of the lid 12 in the first direction D1 and the length of the lid 12 in the second direction D2. The lid 12 is fixed to the base 11. For example, the lid 12 is fixed to the protrusion 11c of the base 11 with an adhesive. The multi-core fiber 3 and the multiple first alignment components 2 are sandwiched between the V-groove 11d and the lid 12.

[0025] The lid 12 has an end face 12a. The end face 12a is a surface of the lid 12 facing the direction opposite to the first direction D1. The end face 12a faces the optical waveguide substrate 30. The end face 12a may be inclined with respect to the third direction D3 when viewed from the second direction D2.

[0026] The single-core fiber array 20 holds a plurality of single-core fibers 4 and a plurality of second alignment components 5. In one example, the single-core fiber array 20 holds four single-core fibers 4. In one example, the single-core fiber array 20 holds two second alignment components 5. The second alignment components 5 may be, for example, a single-core fiber other than the single-core fiber 4.

[0027] The second alignment component 5 extends along the single-core fiber 4. The second alignment component 5 is a component for aligning the multiple single-core fibers 4 with a core group 32, which will be described later. The multiple second alignment components 5 are lined up along the second direction D2. The multiple second alignment components 5 and the multiple single-core fibers 4 are lined up along the second direction D2. The multiple single-core fibers 4 are arranged between the multiple second alignment components 5. The multiple second alignment components 5 are arranged with the multiple single-core fibers 4 sandwiched between them. In one example, four single-core fibers 4 are arranged between two second alignment components 5. The multiple second alignment components 5 are arranged at intervals d2 (see FIG. 6 ).

[0028] The first alignment component 2 and the second alignment component 5 may be disconnected after completing the optical connection between the core group 32 and the single-core fiber 4, and the optical connection between the core group 32 and the multi-core fiber 3. In this case, it becomes easier to accommodate the optical connection structure 1 in a housing that accommodates the optical connection structure 1.

[0029] 1 and 2, the single-core fiber array 20 has a base 21 and a lid 22. The shape and size of the base 21 are, for example, similar to the shape and size of the above-described base 11. The base 21 has an end face 21a.

[0030] The base 21 has an upper surface 21b. A plurality of second alignment components 5 and single-core fibers 4 are placed on the upper surface 21b. The second alignment components 5 are, for example, optical fibers with a coating. The boundary between the portion where both the second alignment components 5 and the single-core fibers 4 are coated and the portion where the coatings of both the second alignment components 5 and the single-core fibers 4 have been removed is located on the upper surface 21b.

[0031] A protrusion 21c that protrudes toward the third direction D3 is formed in a portion of the base 21 closer to the optical waveguide substrate 30. FIG. 6 is a front view showing the end faces 21a, 22a of the single-core fiber array 20. A plurality of V-shaped grooves 21d are formed on the surface of the protrusion 21c facing the third direction D3. In one example, six V-shaped grooves 21d are formed. The V-shaped grooves 21d extend along the first direction D1. The plurality of V-shaped grooves 21d are lined up along the second direction D2. Single-core fibers 4 are placed in the central four V-shaped grooves 21d of the plurality of V-shaped grooves 21d. Second alignment components 5 are placed in the V-shaped grooves 21d located on both sides of the central four V-shaped grooves 21d. The coatings of both the single-core fibers 4 and the second alignment components 5 placed in the V-shaped grooves 21d have been removed.

[0032] As shown in FIGS. 1 and 2, the lid 22 has a rectangular parallelepiped shape. The length of the lid 22 in the third direction D3 is shorter than the length of the lid 22 in the first direction D1 and the length of the lid 22 in the second direction D2. The lid 22 is fixed to the protruding portion 21c of the base 21. The lid 22 is fixed to the protruding portion 21c of the base 21, for example, by an adhesive. The multiple single-core fibers 4 and the multiple second alignment components 5 are sandwiched between the V-groove 21d and the lid 22 (see FIG. 6). The multiple V-grooves 21d are formed, and the multiple single-core fibers 4 and the multiple second alignment components 5 are placed in the multiple V-grooves 21d, thereby enabling the lid 22 to be stably fixed.

[0033] The lid 22 has an end face 22a. The end face 22a is a surface of the lid 22 facing the first direction D1. The end face 22a faces the optical waveguide substrate 30. The end face 22a may be inclined with respect to the third direction D3 when viewed from the second direction D2.

[0034] The optical waveguide substrate 30 is, for example, a three-dimensional optical waveguide. The material of the optical waveguide substrate 30 is, for example, glass. The optical waveguide substrate 30 has a base 33, a first lid 34, and a second lid 35. The base 33 has a rectangular parallelepiped shape. The length of the base 33 in the first direction D1 is longer than the length of the base 33 in the second direction D2 and the length of the base 33 in the third direction D3.

[0035] The base 33 has a first end face 33a (end face) and a second end face 33b. The first end face 33a is the face of the base 33 facing the first direction D1. The second end face 33b is the face of the base 33 facing the opposite direction to the first direction D1. The first end face 33a faces the multicore fiber array 10. The first end face 33a is fixed to the end face 11a of the base 11 of the multicore fiber array 10. The first end face 33a may be inclined with respect to the third direction D3 when viewed from the second direction D2.

[0036] The second end face 33b faces the single-core fiber array 20. The second end face 33b is fixed to the end face 21a of the base 21 of the single-core fiber array 20. The second end face 33b may be inclined with respect to the third direction D3 when viewed from the second direction D2.

[0037] The base 33 has an upper surface 33c. The upper surface 33c is the surface of the base 33 facing the third direction D3. The first lid 34 is disposed on the upper surface 33c of the base 33. The first lid 34 is disposed at an end of the upper surface 33c closer to the multicore fiber array 10. The first lid 34 has a rectangular parallelepiped shape. The length of the first lid 34 in the second direction D2 is longer than the length of the first lid 34 in the third direction D3 and the length of the first lid 34 in the first direction D1.

[0038] The first lid 34 has a first end face 34a (end face). The first end face 34a is a face of the first lid 34 facing the first direction D1. The first end face 34a faces the multicore fiber array 10. The first end face 34a of the first lid 34 is fixed to the end face 12a of the lid 12 of the multicore fiber array 10. The first end face 34a may be inclined with respect to the third direction D3 when viewed from the second direction D2.

[0039] The second lid 35 is disposed on the upper surface 33c of the base 33. The second lid 35 is disposed at an end of the upper surface 33c closer to the single-core fiber array 20. The second lid 35 has a rectangular parallelepiped shape. The length of the second lid 35 in the second direction D2 is longer than the length of the second lid 35 in the third direction D3 and the length of the second lid 35 in the first direction D1.

[0040] The second lid 35 has a second end face 35b. The second end face 35b is a surface of the second lid 35 facing in the opposite direction to the first direction D1. The second end face 35b of the second lid 35 is fixed to the end face 22a of the lid 22 of the single-core fiber array 20. The second end face 35b may be inclined with respect to the third direction D3 when viewed from the second direction D2.

[0041] An adhesive may be used to fix the end faces 11a and 12a of the multi-core fiber array 10 to the first end faces 33a and 34a of the optical waveguide substrate 30, and to fix the end faces 21a and 22a of the single-core fiber array 20 to the second end faces 33b and 35b of the optical waveguide substrate 30. An ultraviolet-curing adhesive may be used as the adhesive.

[0042] The core group 32 is a waveguide through which an optical signal is transmitted. The core group 32 and the alignment core 31 are formed, for example, by drawing with a laser on the optical waveguide substrate 30. The core group 32 and the alignment core 31 are, for example, high refractive index regions formed by altering glass due to multiphoton absorption.

[0043] The core group 32 is formed inside the optical waveguide substrate 30. Specifically, the core group 32 is formed inside the base 33. The core group 32 extends along the first direction D1. The core group 32 is located in the center of the optical waveguide substrate 30 (base 33) in the second direction D2. The core group 32 is also located close to the upper surface 33c of the base 33.

[0044] The core group 32 has a plurality of waveguides 32a. In one example, the core group 32 has four waveguides 32a. The plurality of waveguides 32a are aligned along the second direction D2. The intervals between the plurality of waveguides 32a in the second direction D2 become smaller as they approach the multicore fiber array 10. At a position of the optical waveguide substrate 30 closer to the multicore fiber array 10, the plurality of waveguides 32a are aligned along both the second direction D2 and the third direction D3. In one example, two waveguides 32a are aligned along the second direction D2, and two waveguides 32a are aligned along the third direction D3 (see FIG. 7 ).

[0045] The spacing between the multiple waveguides 32a may be constant at a position closer to the multi-core fiber array 10 than the center of the optical waveguide substrate 30. The spacing between the multiple waveguides 32a may increase from the center of the optical waveguide substrate 30 toward the single-core fiber array 20 toward the single-core fiber array 20. On the second end face 35b of the optical waveguide substrate 30, the multiple waveguides 32a are aligned along the second direction D2.

[0046] The core group 32 is optically connected to each of the multicore fiber 3 and the plurality of single-core fibers 4. The multicore fiber 3 is optically connected to an end of the core group 32 closer to the multicore fiber array 10. The single-core fiber 4 is optically connected to an end of the core group 32 closer to the single-core fiber array 20. The end of each waveguide 32a closer to the multicore fiber array 10 is optically connected to each core 3a (see FIG. 5) of the multicore fiber 3. The end of each waveguide 32a closer to the single-core fiber array 20 is optically connected to a core of the single-core fiber 4. Optical signals are distributed and aggregated by the core group 32. The core group 32 has a FIFO function.

[0047] The alignment core 31 is formed inside the optical waveguide substrate 30. Specifically, the alignment core 31 is formed inside the base 33. The alignment core 31 is linear. The alignment core 31 extends along the first direction D1. The alignment core 31 is disposed near the end of the optical waveguide substrate 30 (base 33) in the second direction D2. The alignment core 31 is also located near the top surface 33c of the base 33. The optical waveguide substrate 30 has a plurality of alignment cores 31. In one example, the optical waveguide substrate 30 has two alignment cores 31. The plurality of alignment cores 31 are formed, for example, parallel to each other.

[0048] The alignment core 31 is optically connected to each of the first alignment component 2 and the second alignment component 5. Specifically, the first alignment component 2 is optically connected to the end of the alignment core 31 closer to the multi-core fiber array 10. The second alignment component 5 is optically connected to the end of the alignment core 31 closer to the single-core fiber array 20.

[0049] Fig. 5 is a front view showing the end faces 11a and 12a of the multicore fiber array 10. Fig. 7 is a front view showing the first end faces 33a and 34a of the optical waveguide substrate 30. Ends of the core group 32 and ends of the alignment cores 31 are exposed at the first end faces 33a and 34a. At the first end faces 33a and 34a, the core group 32 and the alignment cores 31 are aligned along the second direction D2.

[0050] The multiple alignment cores 31 are arranged at intervals d3. The arrangement interval d1 of the multiple first alignment components 2 matches the arrangement interval d3 of the multiple alignment cores 31. This makes it easy to position the multicore fiber array 10 and the optical waveguide substrate 30 in the rotation direction, which is the direction of rotation around an axis extending along the first direction D1, when connecting the multicore fiber array 10 and the optical waveguide substrate 30. Here, "matching" is not limited to perfect matching, but also includes being within a range in which a substantial effect can be obtained, taking into account manufacturing errors and variations.

[0051] Fig. 8 is a front view showing the second end faces 33b, 35b of the optical waveguide substrate 30. As shown in Fig. 8, the end of the core group 32 and the end of the alignment core 31 are exposed at the second end faces 33b, 35b. At the second end faces 33b, 35b, the core group 32 and the alignment core 31 are aligned along the second direction D2.

[0052] 6 and 8, the arrangement interval d2 of the multiple second alignment components 5 matches the arrangement interval d3 of the multiple alignment cores 31. This makes it easy to position the single-core fiber array 20 and the optical waveguide substrate 30 in the rotation direction described above when connecting the single-core fiber array 20 and the optical waveguide substrate 30.

[0053] In the optical waveguide substrate 30, a core group 32 is arranged between a plurality of alignment cores 31. The alignment cores 31, the core group 32, and the alignment core 31 are arranged in this order along the second direction D2. The plurality of alignment cores 31 are arranged with the core group 32 sandwiched between them.

[0054] 5 and 7, the first alignment component 2 will be described in further detail. The first alignment component 2 has a core portion 2a that guides light. The area of ​​the core portion 2a exposed at the end face 2b of the first alignment component 2 facing the optical waveguide substrate 30 is larger than the area of ​​the alignment core 31 exposed at the first end faces 33a, 34a of the optical waveguide substrate 30 facing the multicore fiber array 10.

[0055] The width of the end portion of the first alignment component 2 closer to the optical waveguide substrate 30 is larger than the width of the alignment core 31 exposed at the first end faces 33a, 34a of the optical waveguide substrate 30. The first alignment component 2 may have, for example, a shape in which the width of the end portion is enlarged. For example, the first alignment component 2 may have a shape that widens toward the optical waveguide substrate 30. In this way, the shape of the first alignment component 2 is not particularly limited.

[0056] Furthermore, the cross-sectional area of ​​the core portion 2a perpendicular to the first direction D1 may be larger than the area of ​​the alignment core 31 exposed at the first end faces 33a, 34a of the optical waveguide substrate 30 over the entire first direction D1. The first alignment component 2 may be a multimode fiber. However, the first alignment component 2 is not limited to a multimode fiber having a core-clad structure. The first alignment component 2 may be any component that has a core portion 2a that guides light, and may be, for example, a component with surrounding air as a cladding. The first alignment component 2 may be, for example, a quartz glass rod or an acrylic rod.

[0057] Next, an example of an alignment method for the optical connection structure 1 according to this embodiment will be described. First, a multicore fiber array 10 holding a multicore fiber 3 and a plurality of first alignment components 2 is brought close to an optical waveguide substrate 30. Furthermore, the first end face 33a and the end face 11a are adjusted so that they are parallel to each other. Then, a single-core fiber array 20 holding a plurality of single-core fibers 4 and a plurality of second alignment components 5 is brought close to the optical waveguide substrate 30. Furthermore, the second end face 33b and the end face 21a are adjusted so that they are parallel to each other. Next, the positions of the first alignment component 2 and the alignment core 31 in the second direction D2 are aligned. At this time, the distance between the approached end faces is preferably 3 μm or more and 20 μm or less.

[0058] Thereafter, alignment light is incident on the second alignment component 5 from the single-core fiber array 20 toward the optical waveguide substrate 30. Then, the intensity of the incident alignment light when it passes from the second alignment component 5 through the alignment core 31 and enters the first alignment component 2 is measured by an intensity measuring device. At the position where the intensity is highest, the optical waveguide substrate 30 and the single-core fiber array 20 are fixed to each other with an ultraviolet-curing adhesive or the like. The intensity measuring device is connected to the ends of the multi-core fiber 3 and the first alignment component 2 opposite to the optical waveguide substrate 30.

[0059] Next, alignment light is incident on the plurality of single-core fibers 4 from the single-core fiber array 20 toward the optical waveguide substrate 30. Then, the intensity of the incident alignment light when it passes from each single-core fiber 4 through the core group 32 and enters the multi-core fiber 3 is measured by an intensity measuring device. The multi-core fiber array 10 holding the multi-core fibers 3 is rotated in the rotation direction described above so that the intensity becomes the highest. At the position where the intensity becomes the highest, the multi-core fiber array 10 is fixed to the optical waveguide substrate 30 with an ultraviolet-curing adhesive or the like. This completes a series of steps in the alignment method for the optical connection structure 1.

[0060] Next, the effects obtained from the optical connection structure 1 according to this embodiment will be described in more detail. In the optical connection structure 1, the area of ​​the core portion 2a exposed at the end face 2b of the first alignment component 2 facing the optical waveguide substrate 30 is larger than the area of ​​the alignment core 31 exposed at the first end faces 33a, 34a of the optical waveguide substrate 30 facing the multicore fiber array 10. This makes it possible to make the alignment light incident from the alignment core 31 to the first alignment component 2 without performing an excessively precise alignment operation when illuminating the alignment light from the second alignment component 5. As a result, it becomes easier to detect the alignment light, and the alignment operation between the second alignment component 5 and the alignment core 31 becomes easier. This facilitates the alignment operation in optical connection between the cores of the multicore fiber 3 and the multiple single-core fibers 4 and the core group 32 formed in the optical waveguide substrate 30.

[0061] As described above, the multicore fiber array 10 may hold a plurality of first alignment components 2. The single-core fiber array 20 may hold a plurality of second alignment components 5. The optical waveguide substrate 30 may have a plurality of alignment cores 31. The arrangement interval d1 of the plurality of first alignment components 2 may match the arrangement interval d3 of the plurality of alignment cores 31. In this case, it is possible to improve the accuracy of both the alignment between the first alignment components 2 and the alignment cores 31 and the alignment between the second alignment components 5 and the alignment cores 31.

[0062] As described above, the multi-core fiber 3 may be arranged between a plurality of first alignment components 2. A plurality of single-core fibers 4 may be arranged between a plurality of second alignment components 5. A core group 32 may be arranged between a plurality of alignment cores 31. In this case, the plurality of first alignment components 2 are arranged at positions sandwiching the multi-core fiber 3, and the plurality of second alignment components 5 are arranged at positions sandwiching the plurality of single-core fibers 4. The plurality of alignment cores 31 are arranged at positions sandwiching the core group 32. This makes it possible to improve the positional accuracy of the multi-core fiber 3, the optical waveguide substrate 30, and the plurality of single-core fibers 4 when each first alignment component 2 is aligned with each alignment core 31, and when each second alignment component 5 is aligned with each alignment core 31.

[0063] As described above, the first alignment component 2 may include a multimode fiber. In this case, a multimode fiber having a core portion 2a larger than the core diameter of the single-core fiber 4 can be used for alignment.

[0064] (Second embodiment) 9 is a plan view showing an optical connection structure 1A according to the second embodiment. The optical connection structure 1A differs from the optical connection structure 1 described above in that markers 40 are formed on the optical waveguide substrate 30. Therefore, in the following, explanations that overlap with the above description will be omitted as appropriate. Note that in the optical connection structure 1A, the optical waveguide substrate 30 does not have a first lid 34 or a second lid 35.

[0065] The optical waveguide substrate 30 has a marker 40. The marker 40 enables the position of the alignment core 31 to be determined. The marker 40 serves as a guide indicating the position of the alignment core 31 when aligning the first alignment component 2 with the alignment core 31 and when aligning the second alignment component 5 with the alignment core 31. The marker 40 may be formed by a laser.

[0066] For example, the markers 40 are formed on the upper surface 33c of the base 33 of the optical waveguide substrate 30. The markers 40 are formed on an end of the upper surface 33c closer to the multi-core fiber array 10 and an end of the upper surface 33c closer to the single-core fiber array 20. That is, the markers 40 are formed on both ends of the upper surface 33c in the first direction D1.

[0067] For example, when viewed in the third direction D3, the marker 40 is formed at a position shifted in the second direction D2 from the alignment core 31. In other words, when viewed in the third direction D3, the marker 40 is formed at a position that does not overlap the alignment core 31. The optical waveguide substrate 30 has a plurality of markers 40. For example, the optical waveguide substrate 30 has two markers 40 formed at positions that sandwich the alignment core 31.

[0068] The marker 40 may be, for example, a recess recessed from the upper surface 33c of the optical waveguide substrate 30 toward the inside of the optical waveguide substrate 30 (base 33). In this case, the recess is located on the surface of the optical waveguide substrate 30, making it easy to view with a camera. The marker 40 is, for example, linear when viewed from above. The marker 40 extends along the first direction D1. However, the shape of the marker 40 is not limited to this. The shape of the marker 40 may be, for example, rectangular, circular, or spherical.

[0069] Incidentally, the optical waveguide substrate 30 has a three-dimensional optical waveguide, and the alignment core 31 is formed inside the optical waveguide substrate 30 by, for example, a laser. There may be a small difference in refractive index between the alignment core 31 formed by the laser and a portion of the optical waveguide substrate 30 where the alignment core 31 is not formed. In this case, it may not be easy to visually recognize the alignment core 31.

[0070] In contrast, the optical waveguide substrate 30 of the optical connection structure 1A has markers 40 that enable the position of the alignment core 31 to be determined. In this case, it is possible to distinguish between the alignment core 31 and a portion of the optical waveguide substrate 30 where the alignment core 31 is not formed. This makes it possible to identify the position of the alignment core 31. This makes it easier to align the alignment core 31 with the first alignment component 2 and the alignment core 31 with the second alignment component 5.

[0071] Various embodiments of the optical connection structure according to the present disclosure have been described above. However, the present disclosure is not limited to the above-described embodiments. In other words, those skilled in the art will easily recognize that various modifications and variations of the present invention are possible within the scope of the gist of the claims. In other words, the shape, size, number, material, and arrangement of each part of the optical connection structure can be changed as appropriate within the scope of the above-described gist. [Explanation of symbols]

[0072] 1,1A...Optical connection structure 2...First alignment part 2a...Core part 2b...end face 3...Multicore fiber 3a...Core 4...Single-core fiber 5...Second alignment part 10...Multicore fiber array 11...Base 11a...end face 11b…Top surface 11c...Protruding part 11d…V groove 12...Lid 12a...end face 20...Single-core fiber array 21...Base 21a...end face 21b…Top surface 21c...Protruding part 21d…V groove 22...Lid 22a...end face 30...Optical waveguide substrate 31...Alignment core 32...Core group 32a...Waveguide 33...Base 33a...first end surface 33b…Second end surface 33c…Top surface 34...First lid 34a...first end surface 35...Second lid 35b…Second end surface 40...Marker D1…first direction D2…Second direction D3…Third direction d1~d3...Placement interval

Claims

1. An optical connection structure for optically connecting a multicore fiber having a plurality of cores and a plurality of single-core fibers to each other, a multicore fiber array that holds the multicore fiber and a first alignment component that extends along the multicore fiber; a single-core fiber array holding a plurality of the single-core fibers and a second alignment component extending along the single-core fibers; an optical waveguide substrate having a core group optically connected to each of the multi-core fiber and the plurality of single-core fibers, and an alignment core optically connected to each of the first alignment component and the second alignment component; Equipped with the first alignment component has a core portion that guides light; an area of ​​the core portion exposed on an end surface of the first alignment component facing the optical waveguide substrate is larger than an area of ​​the alignment core exposed on an end surface of the optical waveguide substrate facing the multi-core fiber array; Optical connection structure.

2. the multi-core fiber array holds a plurality of the first alignment components; the single-core fiber array holds a plurality of the second alignment components; the optical waveguide substrate has a plurality of the alignment cores, the arrangement intervals of the plurality of first alignment components match the arrangement intervals of the plurality of alignment cores; The optical connection structure according to claim 1 .

3. the multi-core fiber array holds a plurality of the first alignment components; the single-core fiber array holds a plurality of the second alignment components; the optical waveguide substrate has a plurality of the alignment cores, the multi-core fiber is disposed between a plurality of the first alignment components; a plurality of the single-core fibers are disposed between a plurality of the second alignment components; the core group is disposed between a plurality of the alignment cores; The optical connection structure according to claim 1 .

4. the first alignment component includes a multimode fiber; The optical connection structure according to claim 1 .

5. the optical waveguide substrate has a marker that enables the position of the alignment core to be identified; The optical connection structure according to any one of claims 1 to 4.

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