Optical connection structure, optical module, and method for manufacturing optical module

Abstract

To provide an optical connection structure capable of optically connecting an optical fiber to an optical element simply and easily, and to provide an optical module and a method for manufacturing the same.SOLUTION: An optical connection structure according to one embodiment comprises: an optical element that is provided with a substrate, and a first optical waveguide formed on the substrate and extending in a first direction; and an optical fiber including a second optical waveguide extending in the first direction. The optical element has a connection surface crossing the first direction. In a plane view of the substrate, the connection surface has a first recessed part recessed in the first direction and a second recessed part further recessed in the first direction inside the first recessed part. The optical fiber enters the first recessed part to be connected to the optical element. The second optical waveguide is optically connected to the first optical waveguide in the second recessed part.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to an optical connection structure, an optical module, and a method for manufacturing an optical module. [Background technology]

[0002] Patent Document 1 describes an optical connection structure including an optical waveguide element, an optical fiber, and a connection part that optically connects the optical waveguide element and the optical fiber to each other. The optical waveguide element is a silicon photonics (SiPh) element. The optical waveguide element includes a Si substrate, a BOX (Buried Oxide) layer provided on the Si substrate, a Si waveguide provided on the BOX layer, and an overclad provided on the Si waveguide. A V-groove is formed in the Si substrate. The optical fiber is disposed in the V-groove formed in the Si substrate. The optical fiber is disposed so that its end face faces the end face of the optical waveguide element. Signal light is emitted from the optical fiber, and this signal light is incident on the Si waveguide.

[0003] The connection portion has a self-forming waveguide formed between the optical waveguide element and the optical fiber, and a cladding covering the self-forming waveguide. In a self-forming waveguide, the portion where the refractive index changes due to light irradiation becomes the core. The cladding is a refractive index matching agent applied between the optical fiber and the optical waveguide element. The optical waveguide element has an inclined surface facing the end face of the optical fiber. In a cross section along the optical axis of the optical fiber, the inclined surface is inclined with respect to the end face of the optical fiber so as to approach the bottom of the V-groove as it moves away from the Si waveguide. The self-forming waveguide is formed between this inclined surface and the end face of the optical fiber.

[0004] Patent Document 2 describes an optical module and a manufacturing method thereof. The optical module has a semiconductor chip, an optical fiber, and a support member that supports the optical fiber. The semiconductor chip has an optical waveguide and an optical element on a silicon substrate. The silicon substrate is rectangular plate-shaped. The silicon substrate has a side surface on which an input / output part of the optical waveguide is formed. The optical semiconductor chip is cut out from the semiconductor wafer by stealth dicing technology. The side surface has a laser light irradiation region and a cleavage region. The support member that supports the optical fiber has a surface that is bonded to the side surface. By bonding this surface to the side surface, the optical fiber is optically connected to the input / output part of the optical waveguide. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2022 / 102053 [Patent Document 2] JP 2020-106678 A Summary of the Invention [Problem to be solved by the invention]

[0006] An optical waveguide, such as the above-mentioned self-written waveguide, for optically connecting an optical fiber to an optical element is formed by irradiation with a laser beam. However, there are cases where the laser beam cannot be appropriately irradiated between the optical fiber and the optical element, and in such cases, it may be difficult to form an optical waveguide. Therefore, there is a demand for an optical waveguide that can be easily formed and optically connected to an optical element.

[0007] An object of the present disclosure is to provide an optical connection structure, an optical module, and a method for manufacturing an optical module that can easily optically connect an optical fiber to an optical element. [Means for solving the problem]

[0008] The optical connection structure according to the present disclosure includes a substrate, an optical element including a first optical waveguide formed on the substrate and extending in a first direction, and an optical fiber including a second optical waveguide extending in the first direction. The optical element has a connection surface intersecting the first direction. In a plan view of the substrate, the connection surface has a first recess recessed in the first direction, and a second recess inside the first recess and further recessed in the first direction. The optical fiber enters the first recess and is connected to the optical element. The second optical waveguide is optically connected to the first optical waveguide in the second recess. Effect of the Invention

[0009] According to the present disclosure, an optical fiber can be easily optically connected to an optical element. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a side view diagrammatically illustrating an optical module according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing an optical connection structure according to an embodiment. [Diagram 3] FIG. 3 is a cross-sectional view showing an optical connection structure according to an embodiment. [Figure 4] FIG. 4 is a diagram illustrating a manufacturing process of the optical element according to the embodiment. [Diagram 5] 5A to 5C are plan and cross-sectional views showing a further manufacturing process for the optical element of FIG. [Figure 6] FIG. 6 is a plan view showing a subsequent manufacturing process for the optical element of FIG. [Figure 7] 7 is a cross-sectional view showing a further manufacturing process for the optical element shown in FIG. [Figure 8] FIG. 8 is a cross-sectional view showing an example of a support base for an optical fiber according to the embodiment. [Figure 9] FIG. 9 is a perspective view and a cross-sectional view showing a modified example of the support base for the optical fiber according to the embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing an optical connection structure according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Description of the embodiment of the present invention] First, the contents of the embodiments of the present disclosure will be listed and described. (1) An optical connection structure according to one embodiment includes a substrate, an optical element including a first optical waveguide formed on the substrate and extending in a first direction, and an optical fiber including a second optical waveguide extending in the first direction. The optical element has a connection surface intersecting the first direction. In a plan view of the substrate, the connection surface has a first recess recessed in the first direction, and a second recess further recessed in the first direction inside the first recess. The optical fiber enters the first recess and is connected to the optical element. The second optical waveguide is optically connected to the first optical waveguide in the second recess.

[0012] (5) An optical module according to an embodiment includes the optical connection structure described above.

[0013] (6) A method for manufacturing an optical module according to an embodiment is a method for manufacturing an optical module including the optical connection structure described above. The method for manufacturing an optical module includes the steps of forming a first recess that is recessed in a first direction in a connection surface of a substrate in a plan view, and forming a second recess that is further recessed in the first direction inside the first recess.

[0014] The optical connection structure, the optical module, and the manufacturing method of the optical module include an optical element having a substrate and a first optical waveguide, and an optical fiber including a second optical waveguide. The optical element has a connection surface to which the optical fiber is connected. In a plan view of the substrate, the connection surface has a first recess recessed in a first direction in which the first optical waveguide extends, and a second recess recessed further in the first direction from the first recess. The optical fiber enters the first recess, and the second optical waveguide of the optical fiber is optically connected to the first optical waveguide of the optical element in the second recess. Since the first recess and the second recess are formed, the second recess can be appropriately irradiated with a laser beam while the optical fiber is inserted in the first recess. Therefore, the second optical waveguide of the optical fiber can be easily optically connected to the first optical waveguide of the optical element by appropriately irradiating the laser beam.

[0015] (2) In the above (1), the first optical waveguide may have a first end face facing the second recess, and the second optical waveguide may have a second end face facing the second recess. The second recess may include a resin waveguide that optically connects the second end face to the first end face. In this case, the second optical waveguide of the optical fiber can be easily connected to the first optical waveguide via the resin waveguide.

[0016] (3) In the above (1) or (2), the first recess may have a length greater than the width of the optical fiber in a plan view of the substrate. In this case, the optical fiber can be inserted into the first recess in a plan view of the substrate. This makes it possible to easily optically connect the second optical waveguide of the optical fiber to the first optical waveguide.

[0017] (4) In any of the above (1) to (3), the second recess may have a length smaller than the width of the optical fiber in a plan view of the substrate. In this case, the optical fiber can be prevented from entering the second recess in a plan view of the substrate. This allows the second recess to be more appropriately irradiated with laser light, making it easier to optically connect the optical fiber to the optical element.

[0018] [Details of the embodiment of the present disclosure] Specific examples of the optical connection structure, the optical module, and the manufacturing method of the optical module according to the embodiment of the present disclosure will be described below with reference to the drawings. Note that the present invention is not limited to the following examples, but is intended to include all modifications within the scope of the claims and equivalents thereto. In the description of the drawings, the same or corresponding elements are given the same reference numerals, and duplicated descriptions are omitted as appropriate. The drawings may be partially simplified or exaggerated for ease of understanding, and the dimensional ratios and the like are not limited to those shown in the drawings.

[0019] FIG. 1 is a side view showing an optical module 1 according to this embodiment. For example, the optical module 1 has a base 2, an optical element 10, and an optical fiber 20. The base 2 has a mounting surface 2b extending in both a first direction D1 and a second direction D2 intersecting the first direction D1. The base 2 has a thickness in a third direction D3 intersecting both the first direction D1 and the second direction D2. The base 2 is made of, for example, copper tungsten (CuW) or copper molybdenum (CuMo). The base 2 may be made of ceramic.

[0020] For example, the optical element 10 and the optical fiber 20 are located above the base 2. The optical element 10 and the optical fiber 20 are aligned along the first direction D1. The optical module 1 has a support base 30 that supports the optical fiber 20. Hereinafter, the direction in which the optical fiber 20 is provided as viewed from the support base 30 may be referred to as the top, upper side, or upper side, and the direction in which the support base 30 is provided as viewed from the optical fiber 20 may be referred to as the bottom, lower side, or lower side. The state of an object viewed from the top, upper side, or upper side may be referred to as a planar view. However, these directions and terms are for convenience of explanation and do not limit the arrangement position, direction, etc. of an object.

[0021] The support 30 and the optical element 10 are mounted on the mounting surface 2b of the base 2. The support 30 and the optical element 10 are aligned along the first direction D1. The support 30 will be described in detail later. The optical element 10 is, for example, a SiPh chip manufactured by SiPh (Silicon Photonics) technology. The optical axis of the optical fiber 20 extends along the first direction D1. The optical module 1 may have a package that houses the optical element 10 and the optical fiber 20, and an optical input / output unit that inputs and outputs optical signals to and from the optical fiber 20 to the outside of the optical module 1. Hereinafter, the direction in which the optical element 10 is provided as viewed from the optical fiber 20 may be referred to as the front, front side, or front, and the direction in which the optical fiber 20 is provided as viewed from the optical element 10 may be referred to as the rear, rear side, or rear. Note that these directions and terms are for convenience of explanation and do not limit the arrangement position, direction, etc. of objects.

[0022] The optical element 10 has a connection surface 11 that intersects with the first direction D1. The connection surface 11 is a surface to which the optical fiber 20 is connected. The connection surface 11 is inclined with respect to the third direction D3 so as to move away from the support base 30 as it approaches the mounting surface 2b. That is, the connection surface 11 is inclined with respect to the third direction D3 so as to move closer to the optical fiber 20 as it moves upward. The inclination angle θ of the connection surface 11 with respect to the third direction D3 is, for example, 0° or more and 10° or less. For example, when viewed along the second direction D2, a part of the connection surface 11 overlaps a part of the optical fiber 20. For example, the connection surface 11 includes an opposing surface 11b that faces the support base 30 along the first direction D1.

[0023] FIG. 2 is a cross-sectional view of the optical connection structure 40, the cross section of which is taken along a plane extending in both the first direction D1 and the third direction D3. The optical connection structure 40 according to this embodiment is a structure in which an optical fiber 20 is connected to an optical element 10. As shown in FIG. 2, the optical element 10 has, for example, a substrate 12, a first optical waveguide 13 located above the substrate 12, and a clad 14 surrounding the first optical waveguide 13 above the substrate 12. The first optical waveguide 13 is formed on the substrate 12. The first optical waveguide 13 propagates an optical signal. The first optical waveguide 13 extends along the first direction D1. The optical fiber 20 includes a second optical waveguide 21 extending along the first direction D1. The second optical waveguide 21 is a core that propagates an optical signal, and the optical fiber 20 has a clad 22 surrounding the second optical waveguide 21. The optical fiber 20 is disposed, for example, such that the second optical waveguide 21 is located on an extension of the first optical waveguide 13 of the optical element 10 .

[0024] 3 is a cross-sectional view of the optical connection structure 40 taken along a plane extending in both the first direction D1 and the second direction D2. As shown in FIGS. 2 and 3, the connection surface 11 of the optical element 10 has a first recess 15 recessed forward along the first direction D1 in a plan view of the substrate 12 (when the substrate 12 is viewed along the third direction D3). The first recess 15 is recessed forward in a rectangular shape in a plan view of the substrate 12. For example, the first recess 15 is defined by a first surface 15b, a second surface 15c, a third surface 15d, a fourth surface 15f, and a fifth surface 15h.

[0025] The first surface 15b extends in the first direction D1 from the opposing surface 11b of the connection surface 11. The first surface 15b extends, for example, in both the first direction D1 and the third direction D3. As an example, the first surface 15b is a flat surface. The second surface 15c extends in the second direction D2 from an end of the first surface 15b opposite the opposing surface 11b. The second surface 15c extends, for example, along the second direction D2 toward the third surface 15d. As an example, the second surface 15c is a flat surface. For example, the second surface 15c is inclined with respect to the third direction D3 so as to move away from the optical fiber 20 as it goes downward. The second surface 15c is a surface facing the optical fiber 20. The third surface 15d extends in the first direction D1 from the opposing surface 11b. The third surface 15d faces the first surface 15b along the second direction D2. The third surface 15d extends in both the first direction D1 and the third direction D3. As an example, the third surface 15d is a flat surface.

[0026] The fourth surface 15f extends in the direction opposite to the second direction D2 from the end of the third surface 15d opposite to the facing surface 11b. For example, the fourth surface 15f is formed on an extension line of the second surface 15c in a plan view of the substrate 12. The fourth surface 15f extends toward the first surface 15b along the second direction D2. As an example, the fourth surface 15f is a flat surface. For example, the fourth surface 15f is inclined with respect to the third direction D3 so as to move away from the optical fiber 20 as it goes downward. The fourth surface 15f is a surface facing the optical fiber 20. The fifth surface 15h is located at the lower end of the first surface 15b, the second surface 15c, the third surface 15d, and the fourth surface 15f. The fifth surface 15h extends in both the first direction D1 and the second direction D2. As an example, the fifth surface 15h is a flat surface. The fifth surface 15h is a surface located below the optical fiber 20 in the third direction D3.

[0027] The optical fiber 20 enters the first recess 15 and is connected to the optical element 10. For example, the optical fiber 20 abuts against the first recess 15. More specifically, the optical fiber 20 has an optical fiber end face 20b at an end in the first direction D1. The optical fiber end face 20b is, for example, a plane perpendicular to the first direction D1 in which the optical fiber 20 extends. The optical fiber end face 20b abuts against the second face 15c and the fourth face 15f along the first direction D1 above the fifth face 15h. The second face 15c and the fourth face 15f are abutment portions of the first recess 15. The first recess 15 has a length L2 that is greater than the width L1 of the optical fiber 20 (the length of the optical fiber 20 in the second direction D2) in a plan view of the substrate 12.

[0028] In a state where the optical fiber 20 is inserted in the first recess 15, a gap S is formed at least between the optical fiber 20 and the first surface 15b and between the optical fiber 20 and the third surface 15d. FIG. 3 shows an example in which a gap S is formed both between the optical fiber 20 and the first surface 15b and between the optical fiber 20 and the third surface 15d. The width L1 of the optical fiber 20 corresponds to, for example, the diameter of the optical fiber 20. As an example, the width L1 of the optical fiber 20 is 125 μm, and the length L2 of the first recess 15 in the second direction D2 is 135 μm.

[0029] The connection surface 11 of the optical element 10 has a second recess 16 recessed forward along the first direction D1 inside the first recess 15. The first recess 15 and the second recess 16 are formed by etching. The second recess 16 is recessed forward in a rectangular shape in a plan view of the substrate 12. For example, in a plan view of the substrate 12, the first recess 15 and the second recess 16 are symmetrical with respect to a reference line A extending in the first direction D1 along the first optical waveguide 13. The reference line A is, for example, the center line of the first optical waveguide 13. The second recess 16 is defined by a sixth surface 16b, a seventh surface 16c, an eighth surface 16d, and a ninth surface 16f.

[0030] The sixth surface 16b extends forward from the first recess 15 (the second surface 15c) along the first direction D1. The sixth surface 16b extends, for example, in both the first direction D1 and the third direction D3. As an example, the sixth surface 16b is a flat surface. The seventh surface 16c extends from an end of the sixth surface 16b opposite the first recess 15 toward the eighth surface 16d along the second direction D2. As an example, the seventh surface 16c is a flat surface. For example, the seventh surface 16c is inclined with respect to the third direction D3 so as to be separated from the optical fiber 20 as it extends downward. The seventh surface 16c is a surface facing the optical fiber 20.

[0031] The eighth surface 16d faces the sixth surface 16b along the second direction D2. The eighth surface 16d extends forward from the first recess 15 along the first direction D1. The eighth surface 16d extends in both the first direction D1 and the third direction D3. As an example, the eighth surface 16d is a flat surface. The ninth surface 16f is located at the lower ends of the sixth surface 16b, the seventh surface 16c, and the eighth surface 16d. The ninth surface 16f extends in both the first direction D1 and the second direction D2. As an example, the ninth surface 16f is a flat surface.

[0032] In the second recess 16, the second optical waveguide 21 of the optical fiber 20 is optically connected to the first optical waveguide 13 of the optical element 10. The optical connection structure 40 has a resin layer 41 filled in the second recess 16, and a resin waveguide 42 formed inside the resin layer 41. The resin layer 41 is formed in the second recess 16 so as to cover the resin waveguide 42. That is, the resin waveguide 42 is encapsulated in the resin layer 41.

[0033] The resin waveguide 42 functions as a core through which an optical signal passes, and the resin layer 41 functions as a cladding located around the resin waveguide 42. For example, the resin layer 41 is formed in the second recess 16. However, the resin layer 41 may be formed in the first recess 15 (for example, the gap S). In this case, the resin layer 41 filled and formed in the first recess 15 can be used as an adhesive for fixing the tip of the optical fiber 20 to the optical element 10. The type of the resin layer 41 formed in the first recess 15 may be different from the type of the resin layer 41 formed in the second recess 16.

[0034] In a plan view of the substrate 12, the length L3 in the first direction D1 of the second recess 16 (the length in the first direction D1 of the sixth face 16b and the length in the first direction D1 of the eighth face 16d) is, for example, 300 μm or less. As an example, the length L3 is 100 μm. In a plan view of the substrate 12, the second recess 16 has a length L4 that is smaller than the width L1 of the optical fiber 20. For example, the length L4 is larger than the length in the second direction D2 of the first optical waveguide 13, larger than the length in the second direction D2 of the second optical waveguide 21, and smaller than the width L1 of the optical fiber 20.

[0035] The first optical waveguide 13 has a first end face 13b facing the second recess 16. The second optical waveguide 21 has a second end face 21b facing the second recess 16. The first end face 13b and the second end face 21b face each other along the first direction D1. The first end face 13b may reach the second recess 16 (seventh face 16c) in the first direction D1, or may be separated from the second recess 16. The second recess 16 includes a resin waveguide 42 that optically connects the second end face 21b to the first end face 13b. The resin waveguide 42 is a 3D waveguide formed by irradiating the resin layer 41 with the laser light R. The resin waveguide 42 is formed by irradiating the resin layer 41 with the laser light R from above. The second end face 21b may be on the same plane as the optical fiber end face 20b.

[0036] However, conventionally, there have been cases where laser light could not be properly applied between an optical fiber and an optical element. Fig. 10 is a cross-sectional view showing an optical connection structure 100 according to a comparative example that does not have the first recess 15 and the second recess 16. Note that the support base 30 is not shown in Fig. 10. The optical connection structure 100 is different from the optical connection structure 40 described above in that the optical element 110 does not have the first recess 15 and the second recess 16, but is otherwise the same as the optical connection structure 40.

[0037] The optical element 110 has a connection surface 111 to which the optical fiber 20 is connected, and the connection surface 111 is inclined with respect to the third direction D3 so as to move away from the optical fiber end surface 20b of the optical fiber 20 as it approaches downward. In this case, the butt portion P of the optical fiber 20 against the optical element 110 is located above the first optical waveguide 13 and the second optical waveguide 21. The state in which the connection surface 111 is inclined as shown in FIG. 10 is also called a reverse taper. That is, as the connection surface 111 approaches the mounting surface 2b along the connection surface 111, the distance between that point and the optical fiber end surface 20b in the first direction D1 gradually increases. Therefore, there are cases in which the laser light R cannot be irradiated between the first optical waveguide 13 and the second optical waveguide 21, and it may be difficult to form the resin waveguide 42 between the first optical waveguide 13 and the second optical waveguide 21.

[0038] 2 and 3, in the optical connection structure 40 according to this embodiment, the optical element 10 has a first recess 15 and a second recess 16. The optical fiber 20 is abutted against the first recess 15, and the second recess 16 located deeper than the first recess 15 is filled with a resin layer 41. Therefore, the laser light R can be easily irradiated between the first optical waveguide 13 and the second optical waveguide 21, and the resin waveguide 42 can be easily formed between the first optical waveguide 13 and the second optical waveguide 21.

[0039] Next, an example of a method for manufacturing an optical module according to this embodiment will be described. First, a method for manufacturing an optical element 10 will be described. First, as shown in FIG. 4, a wafer W that is the base of the optical element 10 is prepared (a process for preparing a wafer). Then, as shown in FIG. 4 and FIG. 5, the first optical waveguides 13 are formed in the wafer W in the number equal to the number of optical elements 10 (a process for forming the first optical waveguides). FIG. 4 shows an example in which 25 (5×5) first optical waveguides 13 are formed in one wafer W. Note that in the optical element 10, optical circuits such as optical waveguides other than the first optical waveguide 13, optical splitters, or optical multiplexers may be formed together with the first optical waveguide 13. The first recess 15 and the second recess 16 are formed by etching, which will be described later, and therefore are not included in the cross-sectional view of FIG. 5. However, FIG. 4 illustrates the shapes after etching in order to show the positions where the first recess 15 and the second recess 16 are formed.

[0040] After the first optical waveguide 13 is formed, a mask M is placed on the upper surface of the wafer W to perform patterning, and the regions in which the first recess 15 and the second recess 16 are to be formed are exposed and etched (see FIG. 6). This etching forms the first recess 15 and the second recess 16. At this time, as shown in FIG. 7, the first recess 15 having the second surface 15c and the fourth surface 15f inclined with respect to the third direction D3 so as to move away from the optical fiber 20 as it goes downward, and the second recess 16 having the seventh surface 16c inclined in the same manner are formed on the connection surface 11 (step of forming the first recess, step of forming the second recess). After the first recess 15 and the second recess 16 are formed, dicing is performed along the scribe line B as shown in FIG. 4 (step of performing dicing). As a result, a plurality of optical elements 10 are obtained from the wafer W, and a series of steps in the method of manufacturing the optical element 10 is completed.

[0041] Next, the optical fiber 20 and the support base 30 are prepared (a step of preparing an optical fiber and a support base). Fig. 8 is a cross-sectional view of the optical fiber 20 and the support base 30 cut along a plane perpendicular to the first direction D1. The support base 30 is a support base for fixing the optical fiber 20. The support base 30 supports the optical fiber 20 so that the optical fiber 20 extends along the first direction D1. The support base 30 has a V-groove 31 in which the optical fiber 20 is placed, and for example, the optical fiber 20 is fixed to the V-groove 31 by an adhesive. Note that instead of the support base 30 having the V-groove 31, a support base 30 having a U-groove 32 may be used.

[0042] As shown in FIG. 9, instead of the optical fiber 20 and the support 30, an optical fiber 20 to which a capillary 50 is fixed may be used. The capillary 50 is made of, for example, glass or zirconia. The capillary 50 has, for example, an upper surface 51 and a lower surface 52 extending along both the first direction D1 and the second direction D2, a first side surface 53 extending along both the first direction D1 and the third direction D3, and a second side surface 54 extending along both the second direction D2 and the third direction D3. The capillary 50 has a pair of first side surfaces 53 aligned along the second direction D2 and a pair of second side surfaces 54 aligned along the first direction D1. The optical fiber 20 penetrates the capillary 50 along the first direction D1, and the optical fiber 20 protrudes in the first direction D1 from each of the pair of second side surfaces 54. Even when this capillary 50 is used, it is possible to support the optical fiber 20 so that the optical fiber 20 extends along the first direction D1.

[0043] 2 and 3, the end of the optical fiber 20 in the first direction D1 is inserted into the first recess 15, and the optical fiber end face 20b of the optical fiber 20 is butted against the first recess 15 (a step of butting the optical fiber against the first recess). The second recess 16 is filled with resin to form a resin layer 41 (a step of forming a resin layer). Then, the resin layer 41 is irradiated with laser light R to form a resin waveguide 42 (a step of forming a resin waveguide). The resin waveguide 42 is formed so as to extend from the first end face 13b of the first optical waveguide 13 to the second end face 21b of the second optical waveguide 21. The second optical waveguide 21 is optically coupled to the first optical waveguide 13 by the resin waveguide 42. Even if the position of second end face 21b in second direction D2 or third direction D3 is slightly deviated from the position of first end face 13b, the deviation of the position of second end face 21b relative to first end face 13b can be absorbed because a curved resin waveguide 42 can be formed by irradiating with laser light R. After forming resin waveguide 42 as described above, optical connection structure 40 is completed, and a series of steps in the method for manufacturing optical module 1 is completed.

[0044] Next, the effects obtained from the optical connection structure 40, the optical module 1, and the manufacturing method of the optical module according to the present embodiment will be described in detail. The optical connection structure 40, the optical module 1, and the manufacturing method of the optical module according to the present embodiment include an optical element 10 having a substrate 12 and a first optical waveguide 13, and an optical fiber 20 including a second optical waveguide 21. The optical element 10 has a connection surface 11 to which the optical fiber 20 is connected. In a plan view of the substrate 12, the connection surface 11 has a first recess 15 recessed forward in a first direction D1 in which the first optical waveguide 13 extends, and a second recess 16 recessed further forward from the first recess 15 in the first direction D1. An end of the optical fiber 20 fits into the first recess 15, and the second optical waveguide 21 of the optical fiber 20 is optically connected to the first optical waveguide 13 in the second recess 16. Therefore, by forming the first recess 15 and the second recess 16, the laser light R can be appropriately irradiated to the second recess 16 with the optical fiber 20 inserted in the first recess 15. Therefore, by appropriately irradiating the laser light R, the second optical waveguide 21 of the optical fiber 20 can be easily optically connected to the first optical waveguide 13 of the optical element 10.

[0045] In this embodiment, the first optical waveguide 13 has a first end face 13b facing the second recess 16, and the second optical waveguide 21 has a second end face 21b facing the second recess 16. The second recess 16 includes a resin waveguide 42 that optically connects the second end face 21b to the first end face 13b. In this case, the second optical waveguide 21 of the optical fiber 20 can be easily connected to the first optical waveguide 13 via the resin waveguide 42. The resin waveguide 42 is formed by irradiating the above-mentioned laser light R from a resin applied in the second recess 16 so as to contact the first end face 13b and the second end face 21b. The resin other than the resin waveguide 42 forms a resin layer 41.

[0046] In this embodiment, the first recess 15 has a length L2 greater than the width L1 of the optical fiber 20 in a plan view of the substrate 12. In this case, the end of the optical fiber 20 can be inserted into the first recess 15 in a plan view of the substrate 12. This makes it possible to easily optically connect the second optical waveguide 21 of the optical fiber 20 to the first optical waveguide 13. More specifically, by inserting the end of the optical fiber 20 into the first recess 15, the positional deviation between the center of the second end face 21b and the first end face 13b in the second direction D2 and the third direction D3 can be kept within a range in which the resin waveguide 42 can be formed by irradiation with the laser light R.

[0047] In this embodiment, the second recess 16 has a length L4 smaller than the width L1 of the optical fiber 20 in a plan view of the substrate 12. In this case, the optical fiber 20 can be prevented from entering the second recess 16 in a plan view of the substrate 12. This allows the second recess 16 to be more appropriately irradiated with the laser light R, which facilitates optical connection of the optical fiber 20 to the optical element 10. In addition, by setting the length L3 of the second recess 16 in the first direction D1 to an appropriate value, the distance between the second end face 21b and the first end face 13b in the first direction D1 can be kept within a range in which the resin waveguide 42 can be formed by irradiation with the laser light R.

[0048] The above describes the embodiments of the optical connection structure, optical module, and manufacturing method of the optical module according to the present disclosure. However, the present invention is not limited to the above-mentioned embodiments, and may be further modified within the scope of the gist described in the claims. That is, the configuration, shape, size, material, number, and arrangement of each part of the optical connection structure and optical module according to the present disclosure, as well as the content and order of the steps of the manufacturing method of the optical module, are not limited to the above-mentioned embodiments and can be appropriately changed. [Explanation of symbols]

[0049] 1...Optical module 2. Base 2b…Mounting surface 10...Optical element 11...Connection surface 11b...Opposing surface 12...Substrate 13...First optical waveguide 13b...first end surface 14…Clad 15…First recess 15b...Side 1 15c…Second side 15d...Side 3 15f…Fourth side 15h...Side 5 16…Second recess 16b...Side 6 16c...Side 7 16d...Side 8 16f…Side 9 20...Optical fiber 20b...Optical fiber end face 21...Second optical waveguide 21b…Second end surface 22…Clad 30…Support stand 31...V groove 32...U-groove 40...Optical connection structure 41...Resin layer 42…Resin waveguide 50…Capillary 51…Top surface 52…Bottom surface 53...1st side 54…Second side A...Reference line B…Scribe line M...Mask P…butting part R…Laser light S…Gap W…wafer θ…Inclination angle

Claims

1. An optical element including a substrate and a first optical waveguide formed on the substrate and extending in a first direction; an optical fiber including a second optical waveguide extending in the first direction; Equipped with the optical element has a connection surface that intersects with the first direction, the connection surface has, in a plan view of the substrate, a first recess that is recessed in the first direction, and a second recess that is further recessed in the first direction within the first recess, the optical fiber is inserted into the first recess and connected to the optical element; the second optical waveguide is optically connected to the first optical waveguide in the second recess; Optical connection structure.

2. the first optical waveguide has a first end surface facing the second recess; the second optical waveguide has a second end surface facing the second recess; the second recess includes a resin waveguide that optically connects the second end surface to the first end surface; The optical connection structure according to claim 1 .

3. The first recess has a length greater than a width of the optical fiber in a plan view of the substrate. The optical connection structure according to claim 1 or 2.

4. The second recess has a length smaller than a width of the optical fiber in a plan view of the substrate. The optical connection structure according to claim 1 or 2.

5. An optical module comprising the optical connection structure according to claim 1 or 2.

6. A method for manufacturing an optical module having the optical connection structure according to claim 1 or 2, comprising the steps of: forming a first recess that is recessed in the first direction in a plan view of the substrate on the connection surface; forming a second recess inside the first recess so as to be further recessed in the first direction; Equipped with A method for manufacturing an optical module.

Images