Optical module and manufacturing method of optical module

Abstract

To provide an optical module that can be aligned easily.SOLUTION: An optical module 20 includes: a first clad layer 50 formed on a board 30; a first groove section 51 penetrating the first clad layer 50 in a thickness direction; and a second clad layer 60 formed on an upper surface of the first clad layer 50. The optical module 20 includes: a second groove section 62 penetrating the first clad layer 50 and the second clad layer 60 in the thickness direction; a silicon photonics component 70 mounted on the upper surface of the first clad layer 50; and a single mode fiber 80 fitted to the second groove section 62. The silicon photonics component 70 has a light axis A1 positioned below a lower surface of a body section 71. The lower surface of the body section 71 is in contact with the upper surface of the first clad layer 50. The light axis A1 is housed in the first groove section 51. An outer peripheral surface of the single mode fiber 80 abuts on a bottom surface of the second groove section 62 and also abuts on an inner wall surface 64 of the second groove section 62.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an optical module and a method for manufacturing the optical module. [Background technology]

[0002] Conventionally, optical modules used in optical communications are known that have silicon photonics components and optical fibers (see, for example, Patent Document 1). In an optical module, it is necessary to align the optical axis of the silicon photonics component with the core of the optical fiber with high precision. That is, in an optical module, it is necessary to perform highly accurate core alignment to align the optical axes of the silicon photonics component and the optical fiber. In particular, when the optical fiber is a single mode fiber, the core diameter of the single mode fiber is about 10 μm, so that only a few μm of positional deviation can be tolerated in the alignment, and high-precision core alignment is required. For such core alignment, active alignment is used. In active alignment, light is emitted from the silicon photonics component, while the distribution of the light is monitored, and the single mode fiber is aligned with the silicon photonics component so that the light is most intense. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-079061 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, active alignment requires dedicated equipment and a long operation time, so there is a need for a technology that can align silicon photonics components and single-mode fibers in a simple manner. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a silicon photonics component mounted on the upper surface of the first clad layer exposed from the second clad layer, and a single mode fiber fitted in the second groove portion, the silicon photonics component having a main body and an optical axis provided at a position protruding downwardly from a lower surface of the main body, the lower surface of the main body being in contact with an upper surface of the first clad layer, a side surface of the main body being in contact with a side surface of the second clad layer, the optical axis being accommodated in the first groove portion, an outer peripheral surface of the single mode fiber being in contact with a bottom surface of the second groove portion and in contact with an inner wall surface of the second groove portion, and the optical axis facing a core of the single mode fiber. Effect of the Invention

[0006] According to one aspect of the present invention, there is an effect that alignment can be easily performed. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic perspective view showing an optical module according to an embodiment. [Diagram 2] FIG. 2 is a schematic plan view showing an optical module according to an embodiment. [Diagram 3] FIG. 3 is a schematic cross-sectional view (cross-sectional view taken along line 3-3 in FIG. 2) showing the optical module according to an embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view (cross-sectional view taken along line 4-4 in FIG. 2) showing the optical module according to an embodiment. [Diagram 5] FIG. 5 is a schematic cross-sectional view (cross-sectional view taken along line 5-5 in FIG. 2) showing an optical module according to an embodiment. [Figure 6] FIG. 6 is a schematic plan view showing a method for manufacturing an optical module according to an embodiment. [Figure 7]FIG. 7 is a schematic plan view showing a method for manufacturing an optical module according to an embodiment. [Figure 8] FIG. 8 is a schematic cross-sectional view (cross-sectional view taken along line 8-8 in FIG. 7) showing a method for manufacturing the optical module according to an embodiment. [Figure 9] FIG. 9 is a schematic plan view showing a method for manufacturing an optical module according to an embodiment. [Figure 10] FIG. 10 is a schematic cross-sectional view (cross-sectional view taken along line 10-10 in FIG. 9) showing a method for manufacturing an optical module according to an embodiment. [Figure 11] FIG. 11 is a schematic perspective view showing a method for manufacturing the optical module according to an embodiment. [Figure 12] FIG. 12 is a schematic plan view showing a method for manufacturing an optical module according to an embodiment. [Figure 13] FIG. 13 is a schematic cross-sectional view (cross-sectional view taken along line 13-13 in FIG. 12) showing a method for manufacturing the optical module according to an embodiment. [Figure 14] FIG. 14 is a schematic cross-sectional view (cross-sectional view taken along line 14-14 in FIG. 12) showing a method for manufacturing the optical module according to an embodiment. [Figure 15] FIG. 15 is a schematic perspective view showing a method for manufacturing the optical module according to an embodiment. [Figure 16] FIG. 16 is a schematic cross-sectional view showing a method for manufacturing an optical module according to an embodiment. [Figure 17] FIG. 17 is a schematic cross-sectional view showing a method for manufacturing an optical module according to an embodiment. [Figure 18] FIG. 18 is a schematic cross-sectional view showing a method for manufacturing an optical module according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment will be described with reference to the accompanying drawings. In addition, for convenience, the attached drawings may show characteristic parts in an enlarged manner to make the characteristics easier to understand, and the dimensional ratios of each component may differ from one drawing to another. In addition, in the cross-sectional views, in order to make the cross-sectional structure of each member easier to understand, the hatching of some members is shown instead of a matte pattern, and the hatching of some members is omitted. In each drawing, the X-axis, Y-axis, and Z-axis, which are mutually perpendicular, are illustrated. In the following description, for convenience, the direction extending along the X-axis is referred to as the X-axis direction, the direction extending along the Y-axis is referred to as the Y-axis direction, and the direction extending along the Z-axis is referred to as the Z-axis direction. In this specification, the term "planar view" refers to viewing an object from the Z-axis direction unless otherwise specified. In this specification, the term "planar shape" refers to the shape of an object viewed from the Z-axis direction unless otherwise specified. In addition, in this specification, "opposite" refers to surfaces or members being in front of each other, and includes not only the case where each is completely in front of the other, but also the case where each is partially in front of the other. In this specification, the term "facing" includes not only the case where two members are separated from each other, but also the case where two members are in contact with each other.

[0009] (Overall configuration of optical module 20) 1 and 2, the optical module 20 has a substrate 30, a metal layer 40, a first cladding layer 50, and a second cladding layer 60. The optical module 20 has one or more (in this embodiment, one) silicon photonics components 70 mounted on the substrate 30, and one or more (in this embodiment, one) single mode fibers 80 mounted on the substrate 30.

[0010] As shown in Fig. 1, the single mode fiber 80 has a core 81 that propagates an optical signal, and a cladding 82 that surrounds the outer periphery of the core 81. The single mode fiber 80 is formed in a cylindrical shape. The size of the single mode fiber 80 can be set to any size. The diameter (outer diameter) of the single mode fiber 80 in this embodiment is 125 µm. The core diameter of the single mode fiber 80, i.e., the diameter of the core 81, is, for example, about 10 µm.

[0011] (Configuration of substrate 30) The substrate 30 is formed, for example, in a flat plate shape. The substrate 30 is formed, for example, in a rectangular shape in a plan view. A silicon photonics component 70 is mounted on the substrate 30. The substrate 30 may be equipped with optical functional elements and electronic components other than the silicon photonics component 70. Examples of optical functional elements include a light emitting element, an optical modulator, an optical amplifier, and an optical attenuator. The substrate 30 is, for example, a wiring substrate having wiring electrically connected to the electronic components and the like mounted on the substrate 30.

[0012] (Configuration of Metal Layer 40) The metal layer 40 is provided on the upper surface of the substrate 30. The metal layer 40 is, for example, formed in a solid shape on the upper surface of the substrate 30. As shown in Fig. 2, the metal layer 40 is, for example, formed in a rectangular shape in a plan view. The material of the metal layer 40 may be, for example, copper or a copper alloy. The thickness of the metal layer 40 may be, for example, about 10 µm to 15 µm.

[0013] (Configuration of the first cladding layer 50 and the second cladding layer 60) 3 and 4, the first cladding layer 50 is provided, for example, on the upper surface of the substrate 30. The first cladding layer 50 is provided, for example, on the upper surface of the metal layer 40. As shown in FIG. 3, the first cladding layer 50 is formed, for example, on the upper surface of the substrate 30 so as to cover a portion of the upper surface of the metal layer 40. The first cladding layer 50 is formed, for example, so as to expose a portion of the upper surface of the metal layer 40. The first cladding layer 50 is formed, for example, so as to extend in the X-axis direction.

[0014] The second cladding layer 60 is provided on the upper surface of the first cladding layer 50. The second cladding layer 60 is formed so as to cover a part of the upper surface of the first cladding layer 50. The second cladding layer 60 is formed so as to cover, for example, a part of the upper surface of the first cladding layer 50 on the right side in the figure in the X-axis direction. The second cladding layer 60 has a side surface 61 facing the silicon photonics component 70. The side surface 61 is an end surface facing the left side in the figure among the end surfaces of the second cladding layer 60 in the X-axis direction.

[0015] The material of the first cladding layer 50 and the second cladding layer 60 may be, for example, an epoxy resin. The material of the first cladding layer 50 and the second cladding layer 60 is preferably, for example, a resin material that does not contain a filler. The material of the first cladding layer 50 and the material of the second cladding layer 60 may be the same material as each other, or may be different materials from each other. In this embodiment, the material of the first cladding layer 50 and the material of the second cladding layer 60 are the same material as each other.

[0016] As shown in FIG. 5, the thickness T1 of the first cladding layer 50, specifically, the thickness T1 from the upper surface of the metal layer 40 to the upper surface of the first cladding layer 50, can be about 55 μm to 65 μm. The thickness T1 of the first cladding layer 50 is set, for example, according to the diameter of the single mode fiber 80. The thickness T1 of the first cladding layer 50 is set, for example, according to the protrusion amount of the optical waveguide 75 of the silicon photonics component 70. The thickness T1 of the first cladding layer 50 in this embodiment is 62.5 μm. The thickness T2 of the second cladding layer 60, specifically, the thickness T2 from the upper surface of the first cladding layer 50 to the upper surface of the second cladding layer 60, can be about 55 μm to 65 μm. The thickness T2 of the second cladding layer 60 is set, for example, according to the diameter of the single mode fiber 80. The thickness T2 of the second cladding layer 60 in this embodiment is 60 μm.

[0017] A first groove 51 is formed in the first cladding layer 50. The first groove 51 is formed so as to penetrate the first cladding layer 50 in the thickness direction (here, the Z-axis direction). The first groove 51 is formed so as to expose the upper surface of the metal layer 40 or the upper surface of the substrate 30. The inner wall surface of the first groove 51 is formed so as to extend perpendicularly to the upper surface of the first cladding layer 50, for example. As shown in FIG. 2, the first groove 51 extends along the X-axis direction, for example. The first groove 51 is provided in the center of the first cladding layer 50 in the Y-axis direction, for example. The planar shape of the first groove 51 is formed in a rectangular shape extending in the X-axis direction, for example. The opening width of the first groove 51 along the Y-axis direction can be, for example, about 55 μm to 65 μm.

[0018] The second groove 62 is formed in the second cladding layer 60. The second groove 62 extends, for example, along the X-axis direction. The second groove 62 extends over the entire length of the second cladding layer 60 in the X-axis direction. The second groove 62 is formed so as to divide the second cladding layer 60 into two. The second groove 62 is provided in the center of the second cladding layer 60 in the Y-axis direction, for example. The second groove 62 is formed so as to communicate with the first groove 51. The second groove 62 is formed so as to communicate with the first groove 51 in the X-axis direction. The second groove 62 is formed so as to extend, for example, to the first cladding layer 50 exposed from the second cladding layer 60. That is, the second groove 62 has an extension groove 63 that extends to the single-layer portion of only the first cladding layer 50. In this embodiment, the extension groove 63 is formed so as to extend further to the left side in the figure than the side surface 61 of the second cladding layer 60. The planar shape of the second groove 62 is formed, for example, in a rectangular shape extending in the X-axis direction. The second groove 62 has a predetermined opening width in the Y-axis direction.

[0019] As shown in FIG. 5, the second groove 62 is formed so as to penetrate the second cladding layer 60 and the first cladding layer 50 in the thickness direction. The second groove 62 is formed so as to expose the upper surface of the metal layer 40. In other words, the upper surface of the metal layer 40 exposed from the second groove 62 constitutes the bottom surface of the second groove 62. The second groove 62 has a pair of inner wall surfaces 64. The pair of inner wall surfaces 64 face each other in the width direction of the second groove 62 (here, the Y-axis direction). Each inner wall surface 64 is formed, for example, inclined so as to approach the center of the width direction of the second groove 62 from the upper surface of the second cladding layer 60 toward the metal layer 40. For this reason, the second groove 62 is formed, for example, in a tapered shape in which the opening width becomes smaller from the upper surface of the second cladding layer 60 toward the metal layer 40. Each inner wall surface 64 is formed, for example, in a plane inclined so as to extend linearly without any steps in a cross-sectional view. That is, each inner wall surface 64 is formed so as to be inclined at a certain inclination angle. Here, in this specification, the inclination angle refers to an acute angle between the inner wall surface 64 and the upper surface of the metal layer 40. The inner wall surface 64 of this embodiment is formed so as to be inclined at an inclination angle of 83 degrees. In other words, the second groove portion 62 of this embodiment has a taper angle inwardly inclined at 7 degrees on one side. That is, the second groove portion 62 of this embodiment has a taper angle inwardly inclined at 14 degrees on both sides.

[0020] The opening width of the second groove portion 62, i.e., the opening width of the second groove portion 62 along the Y-axis direction, is larger than the opening width of the first groove portion 51, i.e., the opening width of the first groove portion 51 along the Y-axis direction. The opening width at the lower end of the second groove portion 62 is larger than the opening width of the first groove portion 51. The opening width at the upper end of the second groove portion 62 is, for example, larger than the opening width at the lower end of the second groove portion 62 and larger than the opening width of the first groove portion 51. The opening width at the upper end of the second groove portion 62 can be, for example, about 140 μm to 150 μm. In this embodiment, the opening width at the upper end of the second groove portion 62 is set to 142 μm.

[0021] 2, the extension groove portion 63 is formed so as to communicate with the first groove portion 51. The extension groove portion 63 is formed so as to penetrate the first cladding layer 50 exposed from the second cladding layer 60 in the thickness direction. The opening width of the extension groove portion 63 along the Y-axis direction is larger than the opening width of the first groove portion 51 along the Y-axis direction. Therefore, a step is formed at the boundary portion between the extension groove portion 63 and the first groove portion 51.

[0022] (Configuration of 70 silicon photonics components) The silicon photonics component 70 is mounted on the upper surface of the first cladding layer 50 exposed from the second cladding layer 60. The silicon photonics component 70 is adhered to the upper surface of the first cladding layer 50 by, for example, an adhesive (not shown). For example, a thermosetting adhesive can be used as the adhesive. The silicon photonics component 70 includes, for example, optical elements such as a light emitting element and a light receiving element.

[0023] As shown in Fig. 4, the silicon photonics component 70 has a main body 71 and an optical waveguide 75 protruding from the lower surface of the main body 71. The main body 71 is formed, for example, in a rectangular parallelepiped shape. As shown in Fig. 2, the main body 71 has a side surface 72 facing the side surface 61 of the second cladding layer 60. The side surface 72 is an end surface facing the right side in the figure among the end surfaces of the main body 71 in the X-axis direction.

[0024] As shown in FIG. 4, the optical waveguide 75 is formed so as to protrude downward from the lower surface of the main body 71. The optical waveguide 75 extends along the X-axis direction. The optical waveguide 75 has an optical axis A1 extending along the X-axis direction. The optical axis A1 is provided at a position protruding downward from the lower surface of the main body 71. For example, the optical axis A1 is provided at the center of the plane of the optical waveguide 75 in a plan view seen from the X-axis direction. Although not shown, the optical waveguide 75 has, for example, a core that propagates an optical signal and a cladding that surrounds the outer periphery of the core. The size (for example, core diameter) of the optical axis A1 of the optical waveguide 75 is, for example, smaller than the size (for example, core diameter) of the core 81 of the single mode fiber 80. The size of the optical axis A1 of the optical waveguide 75 is, for example, 1 μm or less. The amount of protrusion of the optical waveguide 75 from the lower surface of the main body 71 can be, for example, about 2 μm to 5 μm.

[0025] The optical waveguide 75 has an end face 76 facing the single mode fiber 80. The end face 76 is an end face of the optical waveguide 75 in the optical axis direction along which the optical axis A1 extends, and is an end face facing the right side in the figure. For example, the end face 76 is a light emitting surface (light emitting surface) when the silicon photonics component 70 has a light emitting capability, and is a light receiving surface when the silicon photonics component 70 does not have a light emitting capability. The end face 76 is formed so as to be flush with the side surface 72 of the main body 71, for example.

[0026] As shown in FIG. 3, the silicon photonics component 70 is mounted on the upper surface of the first clad layer 50 with the lower surface of the main body 71 facing the upper surface of the first clad layer 50 and with the side surface 72 of the main body 71 in contact with the side surface 61 of the second clad layer 60. The silicon photonics component 70 is fixed to the upper surface of the first clad layer 50 by bonding the lower surface of the main body 71 and the upper surface of the first clad layer 50 to each other with an adhesive (not shown). As shown in FIG. 2, the silicon photonics component 70 is mounted on the upper surface of the first clad layer 50 so that the optical waveguide 75 is accommodated in the first groove portion 51 and the extension groove portion 63. The silicon photonics component 70 is mounted on the upper surface of the first clad layer 50 with the optical axis A1 aligned with the center of the second groove portion 62 in the Y-axis direction. That is, the optical axis A1 is provided so as to overlap with the center of the second groove portion 62 in the Y-axis direction in a plan view seen from the X-axis direction.

[0027] Here, the position of the optical axis A1 of the silicon photonics component 70 in the Z-axis direction is adjusted by bringing the lower surface of the main body 71 into contact with the upper surface of the first cladding layer 50. The position of the optical axis A1 of the silicon photonics component 70 in the X-axis direction is adjusted by bringing the side surface 72 of the main body 71 into contact with the side surface 61 of the second cladding layer 60.

[0028] (Configuration of single mode fiber 80) As shown in FIG. 1, the single mode fiber 80 is fitted into the second groove portion 62. The single mode fiber 80 is housed inside the second groove portion 62. As shown in FIG. 5, the single mode fiber 80 is mounted on the upper surface of the metal layer 40 exposed at the bottom of the second groove portion 62. The outer peripheral surface at the lower part of the single mode fiber 80 is in contact with the upper surface of the metal layer 40. The outer peripheral surface of the single mode fiber 80 is in contact with the inner wall surface 64 of the second groove portion 62. The outer peripheral surface of the single mode fiber 80 is in contact with both of the pair of inner wall surfaces 64 of the second groove portion 62.

[0029] The core 81 of the single mode fiber 80 faces the optical waveguide 75 of the silicon photonics component 70 in the X-axis direction. For example, the single mode fiber 80 and the silicon photonics component 70 are arranged so that the planar center of the core 81 overlaps with the planar center of the optical waveguide 75 (i.e., the optical axis A1) in a plan view seen from the X-axis direction. Here, the position of the core 81 of the single mode fiber 80 in the Z-axis direction is adjusted by contacting the upper surface of the metal layer 40 exposed from the second groove portion 62. Also, the position of the core 81 of the single mode fiber 80 in the Y-axis direction is adjusted by contacting the inner wall surface 64 of the second groove portion 62. Specifically, the outer peripheral surface of the single mode fiber 80 is contacted with both of the pair of inner wall surfaces 64 of the second groove portion 62, so that the core 81 of the single mode fiber 80 is adjusted to be disposed at the center of the width direction (here, the Y-axis direction) of the second groove portion 62. In other words, the second groove portion 62 is formed to a size capable of housing the single mode fiber 80 therein with both of a pair of inner wall surfaces 64 in contact with the outer peripheral surface of the single mode fiber 80. The second groove portion 62 is formed to a size such that both of a pair of inner wall surfaces 64 are in contact with the outer peripheral surface of the single mode fiber 80 with the outer peripheral surface of the lower part of the single mode fiber 80 in contact with the upper surface of the metal layer 40.

[0030] 4, the single mode fiber 80 is provided so that an end face 83 in the length direction (here, the X-axis direction) of the single mode fiber 80 abuts against the side face 72 and the end face 76 of the silicon photonics component 70. However, a gap may be generated between the single mode fiber 80 and the silicon photonics component 70.

[0031] The single mode fiber 80 is joined to the silicon photonics component 70 by an optical adhesive 90. The single mode fiber 80 is optically connected (optically coupled) to the optical waveguide 75 of the silicon photonics component 70 by, for example, the optical adhesive 90. The optical adhesive 90 is formed, for example, to fill a gap between the single mode fiber 80 and the silicon photonics component 70. By filling the gap between the single mode fiber 80 and the silicon photonics component 70 with the optical adhesive 90, air reflection can be prevented and the coupling efficiency between the single mode fiber 80 and the silicon photonics component 70 can be increased. The optical adhesive 90 is formed, for example, to cover the entire end surface 83 of the single mode fiber 80. The optical adhesive 90 is formed to cover the entire end surface 76 of the optical waveguide 75. The optical adhesive 90 is formed, for example, to cover a part of the lower surface of the optical waveguide 75. The optical adhesive 90 is formed, for example, to cover the outer peripheral surface at the upper part of the single mode fiber 80. The optical adhesive 90 is formed, for example, so as to rise above the outer peripheral surface at the upper part of the single mode fiber 80. The optical adhesive 90 is formed, for example, so as to cover a part of the side surface 72 of the main body 71 of the silicon photonics component 70. For example, an ultraviolet-curing optical adhesive can be used as the optical adhesive 90. For example, an optical adhesive having a refractive index close to the refractive index of the core of the optical waveguide 75 or the refractive index of the core 81 of the single mode fiber 80 can be used as the optical adhesive 90.

[0032] (Manufacturing method of optical module 20) Next, a method for manufacturing the optical module 20 will be described with reference to Fig. 6 to Fig. 18. For ease of explanation, the parts that will ultimately become the components of the optical module 20 will be described with the reference numerals of the final components.

[0033] First, in the process shown in FIG. 6, a metal layer 40 is formed on the upper surface of the substrate 30. Then, a first clad layer 50 is formed on the upper surface of the substrate 30 so as to cover the metal layer 40. At this time, the first clad layer 50 of this example is formed to have a first groove portion 51 extending over the entire length of the first clad layer 50 in the X-axis direction. For example, a photosensitive resin layer (not shown) that becomes the first clad layer 50 is formed on the entire upper surface of the substrate 30, and after performing exposure and development based on a photolithography method, the photosensitive resin layer is cured to form the first clad layer 50 having the first groove portion 51. By providing the first groove portion 51, the first clad layer 50 is divided into two in the Y-axis direction. The photosensitive resin layer may be formed, for example, by applying a liquid photosensitive resin to the upper surface of the substrate 30, or by laminating a semi-cured photosensitive resin sheet on the upper surface of the substrate 30.

[0034] Next, in the process shown in FIG. 7 and FIG. 8, the second cladding layer 60 is formed on the upper surface of the first cladding layer 50. Specifically, the second cladding layer 60 is formed on the upper surface of each of the two first cladding layers 50 divided by the first groove portion 51. For example, a photosensitive resin layer (not shown) that becomes the second cladding layer 60 is formed on the entire upper surface of the first cladding layer 50, and after performing exposure and development based on a photolithography method, the photosensitive resin layer is cured to form the second cladding layer 60. By this process, the second cladding layer 60 is formed on the upper surface of each of the two first cladding layers 50, and two second cladding layers 60 provided separately from each other in the Y-axis direction are formed. As shown in FIG. 7, each second cladding layer 60 is formed only on a part of the upper surface of each first cladding layer 50 in the X-axis direction. Each second cladding layer 60 is formed so as to overlap with the metal layer 40 in a plan view. The dimension of each second cladding layer 60 along the Y-axis direction is smaller than the dimension of each first cladding layer 50 along the Y-axis direction. For this reason, as shown in Fig. 8, a groove 65 having an opening width larger than that of the first groove 51 is provided between the two second cladding layers 60. The opening width of the groove 65 along the Y-axis direction can be, for example, about 65 µm to 75 µm.

[0035] 9 and 10, the second groove 62 is formed in the first cladding layer 50 and the second cladding layer 60. As shown in FIG. 9, the second groove 62 is formed so as to extend over the entire length of the second cladding layer 60 in the X-axis direction. The second groove 62 is formed so as to have an extension groove 63 extended to the first cladding layer 50 exposed from the second cladding layer 60. The second groove 62 including the extension groove 63 is formed so as to widen the opening width of the first groove 51 and the groove 65 shown in FIG. 7 and FIG. 8, for example. The second groove 62 can be formed by a laser processing method using, for example, an excimer laser or a YAG laser. For example, when high dimensional accuracy is required for the second groove 62, it is preferable to use an excimer laser. In this embodiment, the second groove 62 is formed by irradiating the first cladding layer 50 and the second cladding layer 60 made of epoxy resin with a KrF excimer laser. By using the KrF excimer laser in this manner, as shown in Fig. 10, a pair of inner wall surfaces 64 are formed to have a taper angle inwardly inclined at 7 degrees on one side, i.e., 14 degrees on both sides. In this process, the metal layer 40 functions as a stopper layer for the laser processing. This makes it possible to prevent the substrate 30 below the first cladding layer 50 from being thinned due to, for example, excessive laser processing.

[0036] 11, a silicon photonics component 70 having a main body 71 and an optical waveguide 75 is prepared. Then, the silicon photonics component 70 is placed above a substrate 30 on which a metal layer 40, a first cladding layer 50 having a first groove 51, and a second cladding layer 60 having a second groove 62 are formed.

[0037] Next, in the steps shown in FIG. 12 to FIG. 14, the silicon photonics component 70 is mounted on the upper surface of the first clad layer 50. As shown in FIG. 13, the silicon photonics component 70 is mounted on the upper surface of the first clad layer 50 with the lower surface of the main body 71 in contact with the upper surface of the first clad layer 50. At this time, a thermosetting adhesive (not shown) is applied between the lower surface of the main body 71 and the upper surface of the first clad layer 50. Also, as shown in FIG. 14, the silicon photonics component 70 is mounted on the upper surface of the first clad layer 50 so that the optical waveguide 75 and the optical axis A1 protruding downward from the lower surface of the main body 71 are accommodated inside the first groove portion 51. As a result, the position of the optical axis A1 in the height direction (here, the Z-axis direction) of the optical waveguide 75 can be accurately positioned by the contact between the lower surface of the main body 71 and the upper surface of the first clad layer 50. 12 and 13, the silicon photonics component 70 is mounted on the upper surface of the first cladding layer 50 so that the side surface 72 of the main body 71 abuts against the side surface 61 of the second cladding layer 60. This allows the position of the optical axis A1 of the optical waveguide 75 in the optical axis direction (here, the X-axis direction), specifically the position of the end face 76 in the optical axis direction, to be accurately positioned by abutting the side surface 72 of the main body 71 against the side surface 61 of the second cladding layer 60. Furthermore, as shown in FIG. 12 and FIG. 14, the silicon photonics component 70 is mounted on the upper surface of the first cladding layer 50 in a state where the optical axis A1 of the optical waveguide 75 is aligned so as to coincide with the center of the second groove portion 62 in the width direction (here, the Y-axis direction). Such alignment of the optical axis A1 in the Y-axis direction can be performed, for example, by image recognition using an alignment mark or the like.

[0038] Through the above steps, the position of the optical axis A1 in the X-axis, Y-axis, and Z-axis directions can be suitably determined as shown in Figures 12 to 14. Thereafter, the structure shown in Figures 12 to 14 is subjected to a heat treatment to cure the thermosetting adhesive (not shown) applied between the lower surface of the main body 71 and the upper surface of the first cladding layer 50. As a result, the silicon photonics component 70 is fixed to the upper surface of the first cladding layer 50 with the optical axis A1 of the optical waveguide 75 positioned at a desired position.

[0039] 15 and 16, a single mode fiber 80 having a core 81 and a clad 82 is prepared. Then, the single mode fiber 80 is fitted into the second groove portion 62 from above the second clad layer 60. At this time, as shown in FIG. 16, each inner wall surface 64 of the second groove portion 62 is formed to be inclined so that the opening width of the second groove portion 62 increases as it approaches the upper surface of the second clad layer 60. Therefore, when the single mode fiber 80 is fitted into the second groove portion 62, it is possible to prevent the outer peripheral surface of the single mode fiber 80 from sliding while contacting the inner wall surface 64 of the second groove portion 62.

[0040] As shown in FIG. 17, when the single mode fiber 80 is fitted into the second groove portion 62, the single mode fiber 80 is placed on the upper surface of the metal layer 40 exposed in the second groove portion 62. That is, the outer peripheral surface at the lower part of the single mode fiber 80 is brought into contact with the upper surface of the metal layer 40. As a result, the position of the core 81 in the depth direction of the second groove portion 62 (here, the Z-axis direction) can be accurately positioned by the contact between the outer peripheral surface of the single mode fiber 80 and the upper surface of the metal layer 40. Specifically, in the Z-axis direction, the center of the core 81 can be positioned at a position spaced apart from the upper surface of the metal layer 40 by a distance equal to the radius of the single mode fiber 80 (62.5 μm in this embodiment). As a result, the center of the core 81 is aligned so as to coincide with the optical axis A1 of the optical waveguide 75 in the Z-axis direction. In other words, the thickness T1 of the first cladding layer 50 is adjusted so that, when the single mode fiber 80 is placed on the upper surface of the metal layer 40, the center of the core 81 coincides with the optical axis A1 of the optical waveguide 75 in the Z-axis direction. In this embodiment, the thickness T1 from the upper surface of the metal layer 40 to the upper surface of the first cladding layer 50 is set to 62.5 μm.

[0041] Furthermore, when the single mode fiber 80 is fitted into the second groove portion 62, both of the pair of inner wall surfaces 64 of the second groove portion 62 come into contact with the outer circumferential surface of the single mode fiber 80. This allows the position of the core 81 in the width direction of the second groove portion 62 (here, the Y-axis direction) to be accurately positioned by the contact between the outer circumferential surface of the single mode fiber 80 and the inner wall surface 64 of the second groove portion 62. Specifically, in the Y-axis direction, the center of the core 81 can be positioned at the center of the width direction of the second groove portion 62. This allows the center of the core 81 to be aligned with the optical axis A1 of the optical waveguide 75 in the Y-axis direction.

[0042] Through the above steps, the center of the core 81 of the single mode fiber 80 is aligned so as to coincide with the optical axis A1 of the optical waveguide 75 in both the Y-axis direction and the Z-axis direction. That is, by the simple method of fitting the single mode fiber 80 into the second groove portion 62, the center of the core 81 and the optical axis A1 of the optical waveguide 75 can be aligned so as to coincide with each other.

[0043] 18, the single mode fiber 80 is fitted into the second groove portion 62 (see FIG. 17) such that an end face 83 in the length direction (here, the X-axis direction) of the second groove portion 62 abuts against the side face 72 of the silicon photonics component 70. This allows the position of the core 81 in the length direction of the second groove portion 62, particularly the position of the end face 83, to be accurately positioned by abutting the end face 83 against the side face 72 of the silicon photonics component 70. Note that a gap may be generated between the end face 83 of the single mode fiber 80 and the side face 72 of the silicon photonics component 70.

[0044] Through the above steps, the center of the core 81 of the single mode fiber 80 is aligned so as to coincide with the optical axis A1 of the silicon photonics component 70 in the three directions, the X-axis direction, the Y-axis direction, and the Z-axis direction. This allows the optical axis A1 of the silicon photonics component 70 and the core 81 of the single mode fiber 80 to be aligned with high precision.

[0045] 18, the single mode fiber 80 and the silicon photonics component 70 are bonded together with an optical adhesive 90. For example, a dispenser or the like is used to apply the uncured optical adhesive 90 between the single mode fiber 80 and the silicon photonics component 70. Thereafter, the optical adhesive 90 is cured by irradiation with ultraviolet light, so that the single mode fiber 80 and the silicon photonics component 70 are bonded together with the optical adhesive 90. Note that, if a gap is generated between the end face 83 of the single mode fiber 80 and the side face 72 of the silicon photonics component 70, the optical adhesive 90 is also filled into the gap.

[0046] Next, the effects of this embodiment will be described. (1) The optical module 20 includes a substrate 30, a first cladding layer 50 formed on the substrate 30, a first groove 51 penetrating the first cladding layer 50 in the thickness direction, and a second cladding layer 60 formed on the upper surface of the first cladding layer 50. The optical module 20 includes a second groove 62 penetrating the first cladding layer 50 and the second cladding layer 60 in the thickness direction and communicating with the first groove 51. The optical module 20 includes a silicon photonics component 70 mounted on the upper surface of the first cladding layer 50 exposed from the second cladding layer 60, and a single mode fiber 80 fitted in the second groove 62. The silicon photonics component 70 includes a main body 71 and an optical axis A1 provided at a position protruding downward from the lower surface of the main body 71. The lower surface of the main body 71 is in contact with the upper surface of the first cladding layer 50. The side surface 72 of the main body 71 is in contact with the side surface 61 of the second cladding layer 60. The optical axis A1 is housed in the first groove portion 51. The outer circumferential surface of the single mode fiber 80 is in contact with the bottom surface of the second groove portion 62 and is in contact with the inner wall surface 64 of the second groove portion 62. The optical axis A1 faces the core 81 of the single mode fiber 80.

[0047] According to this configuration, the silicon photonics component 70 is mounted on the upper surface of the first cladding layer 50 with the lower surface of the main body 71 in contact with the upper surface of the first cladding layer 50. The silicon photonics component 70 is mounted on the upper surface of the first cladding layer 50 so that the optical axis A1, which is provided at a position protruding downward from the lower surface of the main body 71, is accommodated inside the first groove 51. As a result, the position of the optical axis A1 in the thickness direction of the first cladding layer 50 (in the present embodiment, the Z-axis direction) can be accurately positioned by the contact between the lower surface of the main body 71 and the upper surface of the first cladding layer 50. That is, the position of the optical axis A1 in the Z-axis direction can be accurately adjusted by adjusting the thickness T1 of the first cladding layer 50. The single mode fiber 80 is fitted inside the second groove 62 with the outer circumferential surface in contact with the bottom surface of the second groove 62. As a result, the position of the core 81 in the thickness direction of the first cladding layer 50 (in the present embodiment, the Z-axis direction) can be accurately positioned by the contact between the outer peripheral surface of the single mode fiber 80 and the bottom surface of the second groove portion 62. That is, the position of the core 81 in the Z-axis direction can be accurately adjusted by adjusting the depth of the second groove portion 62, that is, the thickness T1 of the first cladding layer 50 and the thickness T2 of the second cladding layer 60. Therefore, by adjusting the thickness T1 of the first cladding layer 50 according to the diameter of the single mode fiber 80 and fitting the single mode fiber 80 into the second groove portion 62, the optical axis A1 and the core 81 can be accurately aligned in the Z-axis direction. As a result, the optical axis A1 and the core 81 can be accurately aligned in the Z-axis direction by the simple method of fitting the single mode fiber 80 into the second groove portion 62. As a result, the silicon photonics component 70 and the single mode fiber 80 can be accurately aligned by the simple method.

[0048] (2) Furthermore, the silicon photonics component 70 and the single mode fiber 80 can be aligned without driving the silicon photonics component 70. Therefore, even if it is difficult to drive the silicon photonics component 70, the silicon photonics component 70 and the single mode fiber 80 can be aligned with high precision.

[0049] (3) The planar shape of the second groove portion 62 is formed into a rectangular shape extending in the X-axis direction (first direction). The second groove portion 62 has a pair of inner wall surfaces 64 that face each other in the Y-axis direction (second direction) perpendicular to the X-axis direction. The outer peripheral surface of the single mode fiber 80 is in contact with both of the pair of inner wall surfaces 64. The optical axis A1 is arranged to overlap with the center of the second groove portion 62 in the Y-axis direction in a plan view seen from the X-axis direction.

[0050] According to this configuration, the single mode fiber 80 is fitted inside the second groove portion 62 with the outer circumferential surface in contact with both of a pair of inner wall surfaces 64 facing each other in the Y-axis direction. As a result, the position of the core 81 in the width direction of the second groove portion 62 (here, the Y-axis direction) can be accurately positioned by the contact between the outer circumferential surface of the single mode fiber 80 and the pair of inner wall surfaces 64. Specifically, in the Y-axis direction, the center of the core 81 can be positioned at the center of the width direction of the second groove portion 62. As a result, the core 81 can be accurately positioned in the Y-axis direction and the Z-axis direction by a simple method of fitting the single mode fiber 80 into the second groove portion 62. At this time, when the optical axis A1 of the silicon photonics component 70 is aligned by image recognition or the like so as to coincide with the center of the width direction of the second groove portion 62, the optical axis A1 and the core 81 can be accurately aligned in the Y-axis direction. Here, the alignment of the silicon photonics component 70 by image recognition or the like only requires alignment of the optical axis A1 in one direction, the Y-axis direction. Therefore, the alignment of the optical axis A1 in the Y-axis direction can be performed more easily than when the alignment of the optical axis A1 in two directions, the Y-axis direction and the Z-axis direction, is performed by image recognition or the like.

[0051] (4) The silicon photonics component 70 is mounted on the upper surface of the first cladding layer 50 such that the side surface 72 of the main body 71 abuts against the side surface 61 of the second cladding layer 60. This allows the position of the optical axis A1 of the optical waveguide 75 in the optical axis direction (here, the X-axis direction), specifically the position of the end face 76 in the optical axis direction, to be accurately positioned by the abutment of the side surface 72 of the main body 71 with the side surface 61 of the second cladding layer 60. As a result, the position of the optical axis A1 in the X-axis direction can be accurately positioned by the simple method of abutting the silicon photonics component 70 against the side surface 61 of the second cladding layer 60.

[0052] (5) The single mode fiber 80 is fitted into the second groove portion 62 so that an end face 83 of the single mode fiber 80 in the length direction (here, the X-axis direction) abuts against the side surface 72 of the silicon photonics component 70. This allows the position of the core 81 in the length direction of the single mode fiber 80, particularly the position of the end face 83, to be accurately positioned by abutting the end face 83 against the side surface 72 of the silicon photonics component 70. As a result, the optical axis A1 and the core 81 can be accurately aligned in the X-axis direction by the simple method of abutting the single mode fiber 80 against the silicon photonics component 70.

[0053] (6) Each of the pair of inner wall surfaces 64 is inclined so as to approach the center of the second groove portion 62 in the Y-axis direction from the upper surface of the second cladding layer 60 toward the substrate 30. In this configuration, the second groove portion 62 is formed so that the opening width increases as it approaches the upper surface of the second cladding layer 60. Therefore, when the single mode fiber 80 is fitted into the second groove portion 62, it is possible to prevent the outer peripheral surface of the single mode fiber 80 from sliding while contacting the inner wall surface 64 of the second groove portion 62. This makes it possible to suitably prevent the outer peripheral surface of the single mode fiber 80 and the inner wall surface 64 of the second groove portion 62 from being worn.

[0054] (7) The metal layer 40 is formed on the upper surface of the substrate 30. The first cladding layer 50 is formed on the upper surface of the substrate 30 so as to cover the metal layer 40. The second groove portion 62 is formed so as to expose the upper surface of the metal layer 40. With this configuration, when the second groove portion 62 is formed by the laser processing method, the metal layer 40 can be used as a stopper layer for the laser processing. This can prevent the substrate 30 below the first cladding layer 50 from being thinned due to excessive laser processing. Therefore, the depth of the second groove portion 62 can be accurately formed to a desired depth. As a result, the alignment accuracy of the core 81 in the Z-axis direction can be further improved.

[0055] (8) The optical adhesive 90 is filled in the gap between the silicon photonics component 70 and the single mode fiber 80. As a result, even if a gap occurs between the silicon photonics component 70 and the single mode fiber 80, air reflection in the gap can be prevented, and the coupling efficiency between the single mode fiber 80 and the silicon photonics component 70 can be increased.

[0056] (Other embodiments) The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0057] The structure of the second groove 62 in the above embodiment can be modified as appropriate. For example, the extension groove 63 may be omitted. For example, each inner wall surface 64 of the second groove 62 may be formed to extend perpendicularly to the upper surface of the second cladding layer 60.

[0058] The first cladding layer 50 may be formed so as to cover the entire upper surface of the metal layer 40 . The first cladding layer 50 may be formed only on the upper surface of the metal layer 40. In other words, the first cladding layer 50 does not have to be formed on the upper surface of the substrate 30 exposed from the metal layer 40.

[0059] The formation area of ​​the first groove portion 51 can be changed as appropriate. For example, the length of the first groove portion 51 in the X-axis direction can be shortened as long as it is possible to accommodate the optical waveguide 75 of the silicon photonics component 70.

[0060] The formation region of the metal layer 40 can be changed as appropriate. As long as the metal layer 40 is provided at a position that overlaps with the second groove portion 62 in a plan view, the length of the metal layer 40 in the Y-axis direction may be shortened. The metal layer 40 may be omitted. [Explanation of symbols]

[0061] 20 Optical Module 30 Substrate 40 metal layer 50 First cladding layer 51 First groove 60 Second cladding layer 61 Side 62 Second groove 63 Extension groove 64 Inner Wall Surface 70 Silicon Photonics Parts 71 Main body 72 Side 75 Optical waveguide 76 End face 80 Single mode fiber 81 cores 82 Clad 83 End face 90 Optical Adhesives A1 Optical axis T1 Thickness T2 Thickness

Claims

1. A substrate; a first cladding layer formed on the substrate; a first groove portion penetrating the first cladding layer in a thickness direction; a second cladding layer formed on an upper surface of the first cladding layer; a second groove portion that penetrates the first cladding layer and the second cladding layer in a thickness direction and communicates with the first groove portion; a silicon photonics component mounted on an upper surface of the first cladding layer exposed from the second cladding layer; a single mode fiber fitted in the second groove portion, The silicon photonics component has a main body and an optical axis provided at a position protruding downward from a lower surface of the main body, a lower surface of the main body contacting an upper surface of the first clad layer; a side surface of the main body contacts a side surface of the second clad layer; The optical axis is accommodated in the first groove portion, an outer circumferential surface of the single mode fiber contacts a bottom surface of the second groove portion and an inner wall surface of the second groove portion; The optical module, wherein the optical axis faces a core of the single mode fiber.

2. The single mode fiber is formed in a cylindrical shape, The second groove portion has a planar shape that is rectangular and extends in a first direction, The second groove portion has a pair of inner wall surfaces opposed to each other in a second direction perpendicular to the first direction, an outer circumferential surface of the single mode fiber is in contact with both of the pair of inner wall surfaces; The optical module according to claim 1 , wherein the optical axis is arranged to overlap a center of the second groove portion in the second direction in a plan view seen from the first direction.

3. 3 . The optical module according to claim 2 , wherein each of the pair of inner wall surfaces is inclined so as to approach a center of the second groove portion in the second direction from the upper surface of the second cladding layer toward the substrate.

4. The optical module according to claim 2 , wherein an opening width of the second groove in the second direction is larger than an opening width of the first groove in the second direction.

5. a metal layer formed on an upper surface of the substrate; the metal layer is formed so as to overlap the second clad layer in a plan view, the first cladding layer is formed on the upper surface of the substrate so as to cover the metal layer; the second groove portion is formed so as to expose an upper surface of the metal layer, 2. The optical module according to claim 1, wherein an outer peripheral surface of the single mode fiber is in contact with an upper surface of the metal layer exposed from the second groove portion.

6. The optical module according to claim 1 , wherein the size of the optical axis is smaller than the size of the core.

7. an optical adhesive for bonding the silicon photonics component and the single mode fiber; The optical module according to claim 1 , wherein the optical adhesive is filled in a gap between the silicon photonics component and the single mode fiber.

8. the second groove portion has an extension groove portion extending to a single-layer portion of the first cladding layer, The optical module according to claim 1 , wherein the optical axis is accommodated in the first groove and the extension groove.

9. forming a first cladding layer having a first groove on a substrate; forming a second cladding layer on an upper surface of the first cladding layer; forming a second groove portion that penetrates the first cladding layer and the second cladding layer in a thickness direction and communicates with the first groove portion; a step of mounting a silicon photonics component having a main body and an optical axis provided at a position protruding downward from a bottom surface of the main body on an upper surface of the first cladding layer exposed from the second cladding layer; and fitting a single mode fiber into the second groove portion, the silicon photonics component is mounted on the upper surface of the first clad layer in a state in which a lower surface of the main body is in contact with an upper surface of the first clad layer, a side surface of the main body is in contact with a side surface of the second clad layer, and the optical axis is accommodated in the first groove portion; A method for manufacturing an optical module, comprising the steps of: fitting the single mode fiber into the second groove in a state in which the single mode fiber is in contact with a bottom surface of the second groove and an inner wall surface of the second groove.

10. forming a metal layer on an upper surface of the substrate; the first cladding layer is formed on the upper surface of the substrate so as to cover the metal layer; The method for manufacturing an optical module according to claim 9 , wherein the second groove portion is formed by laser processing so as to penetrate through the first cladding layer and the second cladding layer in a thickness direction and expose an upper surface of the metal layer.

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