Optical module and optical member

Abstract

An optical module (100) is provided with a substrate (10), a light source (21), a first waveguide (24), a light-transmitting-side vertical waveguide, an optical bench (5), and a refractive member (6). The light source (21) is disposed on an upper surface (110) of the substrate (10). The first waveguide (24) has a diffraction member (25) and is disposed on the upper surface (110) of the substrate (10). The light-transmitting-side vertical waveguide (26) is disposed above the diffraction member (25) so as to be inclined with respect to the upper surface (110) of the substrate (10). The optical bench (5) has a second waveguide (53) and a light-transmitting-side mirror (551), and is disposed above the light-transmitting-side vertical waveguide. The refractive member (6) is disposed between the optical bench (5) and the light-transmitting-side vertical waveguide. The refractive member (6) has a first recessed part (61) provided in a surface facing the light-transmitting-side vertical waveguide or a surface facing the light-transmitting-side mirror (551).

Description

Optical module and optical member

[0001] The present disclosure relates to an optical module and an optical member.

[0002] The opto-electrical hybrid device described in Patent Document 1 includes an opto-electrical hybrid substrate, a sealing structure, and a vertical optical waveguide. The opto-electrical hybrid substrate is provided with an optical waveguide for transmitting an optical signal, an electrical signal path for transmitting an electrical signal, and an electronic circuit, as well as an optical modulator, a light source, and / or a photodetector. The sealing structure is provided on the opto-electrical hybrid substrate and covers the opto-electrical hybrid substrate except for a specific portion responsible for inputting and outputting optical signals. The vertical optical waveguide has an optically flat surface and forms an optical path in the specific portion responsible for inputting and outputting optical signals of the opto-electrical hybrid substrate.

[0003] Patent Document 1 describes an optoelectronic hybrid device incorporated into a data transmission module such as an interposer and used as a signal conversion element. When incorporating the optoelectronic hybrid device into the interposer, the optoelectronic hybrid device is fitted into the interposer so that the top surface of the optoelectronic hybrid device faces the top surface of the interposer. The optoelectronic hybrid device and the interposer are mechanically aligned using an alignment jig, and then the two are fixed together. Next, solder bumps on the optoelectronic hybrid device are electrically connected to the top surface terminals of the interposer using a flexible bridge circuit. Then, by fitting the mating pins of the optical connector into the mating holes of the interposer, the alignment between the optical connector and the optoelectronic hybrid device is completed. The optical waveguide and the optical fiber provided in the optical connector are aligned, allowing light emitted from the optical waveguide to be incident on the optical fiber via a 45-degree mirror.

[0004] International Publication No. 2014 / 156962

[0005] In the opto-electric hybrid device described in Patent Document 1, the efficiency of light transmission between the opto-electric hybrid device and the optical fiber may decrease.

[0006] An optical module according to one aspect of the present disclosure includes a substrate, a light source, a first waveguide, a vertical waveguide, an optical bench, and a refractive member. The light source is disposed on an upper surface of the substrate. The first waveguide has a diffractive member and is disposed on the upper surface of the substrate. The vertical waveguide is disposed above the diffractive member and inclined with respect to the upper surface of the substrate. The optical bench has a second waveguide and a mirror and is disposed above the vertical waveguide. The refractive member is disposed between the optical bench and the vertical waveguide. The refractive member has a recess provided on a surface facing the vertical waveguide or a surface facing the mirror.

[0007] An optical module according to one aspect of the present disclosure includes a substrate, a light-receiving component, a vertical waveguide, an optical bench, and a refractive member. The light-receiving component is disposed on an upper surface of the substrate. The vertical waveguide is disposed above the light-receiving component and inclined with respect to the upper surface of the substrate. The optical bench has a waveguide and a mirror and is disposed above the vertical waveguide. The refractive member is disposed between the optical bench and the vertical waveguide. The refractive member has a recess provided on a surface facing the vertical waveguide or a surface facing the mirror.

[0008] An optical element according to one aspect of the present disclosure is used together with an optical chip that emits light. The optical element includes an optical bench and a refractive element. The optical bench has a mirror and is disposed above a vertical waveguide of the optical chip. The refractive element is disposed between the optical bench and the vertical waveguide. The refractive element has a recess provided on a surface facing the vertical waveguide or a surface facing the mirror.

[0009] An optical element according to one aspect of the present disclosure is used together with an optical chip that receives light. The optical element includes an optical bench and a refractive element. The optical bench has a mirror and is disposed above a vertical waveguide of the optical chip. The refractive element is disposed between the optical bench and the vertical waveguide. The refractive element has a recess provided on a surface facing the vertical waveguide or a surface facing the mirror.

[0010] The present disclosure has the advantage that it is possible to improve the light transmission efficiency.

[0011] FIG. 1 is a top view of an optical module according to an embodiment of the present disclosure. FIG. 2 is a perspective view of an optical chip included in the optical module. FIG. 3 is a perspective view of the optical module from below. FIG. 4 is an explanatory diagram showing an outline of a main part of the light-transmitting side of the optical module. FIG. 5 is an explanatory diagram showing an outline of a main part of the optical module, and is an enlarged view of a part of FIG. 4. FIG. 6 is an explanatory diagram showing an outline of a main part of the light-receiving side of the optical module. FIG. 7 is an explanatory diagram showing an outline of a main part of an optical member included in the optical module on the light-receiving side. FIG. 8 is a perspective view of a refractive member included in the optical module from below. FIG. 9 is an explanatory diagram for explaining the path of light passing through a main part of the light-emitting side of the optical module. FIG. 10 is an explanatory diagram for explaining the path of light passing through a main part of the light-emitting side of the optical module. FIG. 11 is an explanatory diagram for explaining the path of light passing through a main part of the light-emitting side of the optical module of Variation 1. FIG. 12 is an explanatory diagram for explaining the path of light passing through a main part of the light-emitting side of the optical module. Fig. 13 is a perspective view from below of a refractive member provided in the optical module of Modification 2. Fig. 14 is an explanatory diagram showing an outline of the main parts of the light-emitting side of the optical module of Modification 3. Fig. 15 is an explanatory diagram showing an outline of the main parts of the light-receiving side of the optical module of Modification 4. Fig. 16 is an explanatory diagram showing an outline of the main parts of the light-receiving side of the optical module of Modification 5.

[0012] Optical modules and optical members according to embodiments of the present disclosure will be described below with reference to the accompanying drawings. However, the following embodiment is merely one of various embodiments of the present disclosure. The following embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Furthermore, each diagram described in the following embodiment is a schematic diagram, and the ratios of the sizes and thicknesses of the components in the diagram do not necessarily reflect the actual dimensional ratios.

[0013] (1) Embodiments (1.1) Overview of the Optical Module The optical module 100 of this embodiment is a device used to transmit and receive optical signals between, for example, two electrical devices. The optical module 100 is electrically connected to, for example, one of the two electrical devices. As shown in FIG. 1 , the optical module 100 also includes an optical fiber cable 9 for optically connecting to the other optical module 100. The optical module 100 has, for example, a function of converting an electrical signal from an electrical device into an optical signal and transmitting the converted optical signal to the other optical module 100 via the optical fiber cable 9. The optical module 100 also has, for example, a function of converting an optical signal received from the other optical module 100 via the optical fiber cable 9 into an electrical signal and transmitting the converted electrical signal to the electrical device. The two electrical devices may be two circuit boards included in one electrical device (e.g., a processor). Alternatively, the two electrical devices may be one circuit board or terminal, etc. included in one electrical device and another circuit board or terminal, etc. included in the other electrical device. However, the optical module 100 may be used to transmit and receive optical signals between one part of a circuit board (or an electronic component / chip) and another part of the circuit board (or an electronic component / chip).The optical module 100 may also be used to transmit and receive light other than optical signals (unmodulated light).

[0014] As described above, the optical module 100 is configured to transmit and receive optical signals via the optical fiber cable 9. Therefore, compared to transmitting and receiving electrical signals via electric wires, the optical module 100 has advantages such as being capable of high-speed, long-distance transmission of large amounts of data, being less susceptible to noise, and being able to achieve electrical isolation by separating electrical devices from each other.

[0015] As shown in FIGS. 1 to 3, the optical module 100 of this embodiment includes an optical chip 1, an optical member 4, and an optical fiber cable 9.

[0016] For convenience, the following description will be given by defining three axes (X-axis, Y-axis, and Z-axis) of a right-handed three-dimensional Cartesian coordinate system for the optical module 100 as shown in FIGS. 1 to 3 . That is, the thickness direction of the rectangular plate-shaped optical chip 1 (see FIG. 2 ) is defined as the Z-axis direction. The direction perpendicular to the Z-axis direction, in which the optical chip 1 and the optical fiber cable 9 are aligned, is defined as the X-axis direction. The width direction of the optical fiber cable 9, perpendicular to both the X-axis direction and the Z-axis direction, is defined as the Y-axis direction. For convenience, the Z-axis direction is defined as the up-down direction, and the side on which the optical member 4 is located relative to the optical chip 1 (positive direction of the Z-axis) is defined as "up," and the opposite side is defined as "down." The X-axis direction is defined as the front-rear direction, and the side on which the optical fiber cable 9 is located relative to the optical chip 1 (positive direction of the X-axis) is defined as "front," and the opposite side is defined as "rear." The Y-axis direction is defined as the left-right direction, and the positive direction of the Y-axis is defined as "left," and the opposite side is defined as "right." However, the definitions of axes and directions in this disclosure merely indicate the relative positional relationships between the components of the optical module 100, and do not limit the orientation of the optical module 100 when in use.

[0017] (1.2) Optical Fiber Cable As shown in FIG. 3, the optical fiber cable 9 includes an optical fiber 91 and a jacket 92 .

[0018] The optical fiber cable 9 includes, for example, a plurality (here, ten) of optical fibers 91. The optical fibers 91 extend parallel to one another along the longitudinal direction of the optical fiber cable 9.

[0019] The jacket 92 is made of resin. The jacket 92 covers and holds the optical fibers 91. The front (rear) ends of the optical fibers 91 are exposed from the jacket 92. As shown in Fig. 4, each of the optical fibers 91 has a core 911 and a cladding 912. For convenience, the configuration of the optical module 100 is shown schematically in each of the explanatory diagrams such as Fig. 4.

[0020] (1.3) Optical Chip As shown in Fig. 2, the optical chip (optical sensor chip) 1 includes a substrate 10. The optical chip 1 also includes, as components on the light-transmitting side, a light source 21, a light-transmitting circuit 22, and a light-transmitting waveguide 23. The optical chip 1 also includes, as components on the light-receiving side, a light-receiving component 31 (see Fig. 6), a light-receiving circuit 32, and a light-receiving waveguide 33.

[0021] The substrate 10 is formed, for example, from a silicon substrate. The substrate 10 is, for example, a rectangular plate in plan view, and is formed, for example, with dimensions of approximately 5 mm x 5 mm. The substrate 10 is provided with a plurality of terminals (pads) 101 that are electrically connected to an external electrical device.

[0022] The substrate 10 is provided with a light source 21, a light-transmitting circuit 22, a light-transmitting waveguide 23, a light-receiving component 31, a light-receiving circuit 32, and a light-receiving waveguide 33. As shown in FIG. 6 , the light-receiving component 31 is provided below the light-receiving waveguide 33 on the substrate 10. As shown in FIG. 2 , the substrate 10 has a recess 102, and the light source 21, the light-transmitting circuit 22, the light-transmitting waveguide 23, the light-receiving component 31, the light-receiving circuit 32, and the light-receiving waveguide 33 are disposed within the recess 102. The substrate 10 is formed in a rectangular plate shape having the recess 102, for example, by placing (bonding) a rectangular frame-shaped second substrate 12 on a rectangular plate-shaped first substrate 11. In this embodiment, the top surface 110 of the substrate 10 includes a bottom surface 111 of the recess 102 (the exposed portion of the top surface of the first substrate 11). The recess 102 of the substrate 10 may be sealed with a glass material or the like.

[0023] (1.3.1) Configuration of the Light-Transmitting Side As shown in Fig. 2 , the light source 21 is disposed on the upper surface 110 of the substrate 10. In the present disclosure, "a predetermined member is disposed on the upper surface 110 of the substrate 10" means that the predetermined member is disposed on the upper surface 110 of the substrate 10 (the bottom surface 111 of the recess 102), or is disposed inside the substrate 10 and embedded slightly below the upper surface 110 (the bottom surface 111 of the recess 102). In this embodiment, the light source 21 is disposed on the upper surface 110 of the substrate 10.

[0024] As shown in Fig. 2, the light source 21 is disposed in the recess 102 of the substrate 10. The light source 21 is disposed in a relatively left rear position within the recess 102 of the substrate 10. As shown in Fig. 4, a placement recess 103 is formed in the bottom surface 111 of the recess 102 of the substrate 10, and the light source 21 is disposed in this placement recess 103. A portion of the light source 21 including an exit port for light A1 is located within the placement recess 103. As shown in Fig. 4, the light source 21 emits light A1 forward.

[0025] The light source 21 is, for example, a laser diode (semiconductor laser). Specific examples of the light source 21 include a Fabry-Perot laser, a DFB (Distributed Feedback) laser, a quantum dot laser, and a surface-emitting laser. However, the light source 21 is not limited to these, and may also be another light-emitting element such as a light-emitting diode.

[0026] The light-transmitting circuit 22 is electrically connected to the terminals 101 of the substrate 10. As shown in FIGS. 2 and 4 , the light-transmitting circuit 22 includes a driver IC (Integrated Circuit) 221. The driver IC 221 is disposed on the upper surface 110 of the substrate 10. The driver IC 221 is disposed in front of the light source 21 in the recess 102 of the substrate 10. The light-transmitting circuit 22 has, for example, a function of controlling the drive of the light source 21, a function of controlling a modulator in response to an electrical signal from an external electrical device, and a function of modulating the light A1 from the light source 21 to generate an optical signal, etc.

[0027] 2 and 4, the light-sending-side waveguide 23 includes a first waveguide 24 and a light-sending-side vertical waveguide 26. For convenience, the light-sending-side vertical waveguide 26 will also be referred to as a "light-sending-side optical pin 26" below.

[0028] The first waveguide 24 is an optical waveguide for guiding light A1 from the light source 21. As shown in FIG. 4 , the first waveguide 24 is disposed on the upper surface 110 of the substrate 10. Here, the first waveguide 24 is embedded in the substrate 10 so that the upper surface of the first waveguide 24 is exposed on the upper surface 110 of the substrate 10 (the bottom surface 111 of the recess 102). The first waveguide 24 extends in the front-to-rear direction along the upper surface 110 of the substrate 10. The first waveguide 24 has a first end 241 (rear end) and a second end 242 (front end) in the longitudinal direction. The first end 241 of the first waveguide 24 faces the light source 21. The first waveguide 24 extends along the optical axis of the light source 21.

[0029] The driver IC 221 is disposed above the first waveguide 24. The light-sending circuit 22 modulates the light A1 passing through the first waveguide 24 by controlling a modulator or the like.

[0030] 5 , the first waveguide 24 has a first waveguide core 248 through which the light A1 mainly propagates, and a first waveguide clad 249 disposed around the first waveguide core 248. The refractive index of the first waveguide clad 249 is smaller than the refractive index of the first waveguide core 248. The first waveguide clad 249 includes a first waveguide upper clad 2491 disposed above the first waveguide core 248, and a first waveguide lower clad 2492 disposed below the first waveguide core 248. The first waveguide upper clad 2491 and the first waveguide lower clad 2492 may be integrally formed from the same material.

[0031] The first waveguide 24 has, for example, a plurality of (four in this example) first waveguide cores 248. Each of the plurality of first waveguide cores 248 may be, for example, a rod-shaped one with a square cross section, a rod-shaped one with a regular hexagonal cross section, or a rod-shaped one with a circular cross section. The plurality of first waveguide cores 248 are aligned in the width direction (left-right direction) of the first waveguide 24. The plurality of first waveguide cores 248 extend parallel to one another along the longitudinal direction of the first waveguide 24.

[0032] 4 and 5, the first waveguide 24 has a diffractive member 25. Note that Fig. 5 is an enlarged view of a region R1 in Fig. 4.

[0033] The diffraction element 25 is provided in the first waveguide 24 near the second end 242 (front end) away from the light source 21. Here, the diffraction element 25 includes a grating coupler 250. The grating coupler 250 has a plurality of recesses (grooves) 251 aligned in the longitudinal direction of the first waveguide 24 and a plurality of protrusions (ridges) 252 between the recesses 251. In other words, the grating coupler 250 has a diffraction grating structure including a periodic uneven structure. In the optical chip 1 of this embodiment, the diffraction grating structure of the grating coupler 250 is formed in the first waveguide core 248. However, this is not a limitation, and the grating coupler 250 (diffraction element 25) may be a separate member from the first waveguide core 248.

[0034] Light A1 emitted from the light source 21 propagates through the first waveguide 24 and reaches the grating coupler 250, where it is diffracted by the grating coupler 250.

[0035] Generally, the emission angle θ of light (emitted light / diffracted light) A1 with respect to the normal N1 of the grating coupler 250 is expressed by the following equation (1) based on the condition that the light beams constructively interact with each other in the diffraction grating.

[0036]

[0037] where λ is the wavelength of light A1 in vacuum, n ｕ－ｃｌａｄ is the refractive index of the first waveguide upper cladding 2491, n ｅｆｆ is the effective refractive index of the first waveguide 24, Λ is the period of the diffraction grating (see FIG. 5), and m is the order of the diffracted light (m=0, ±1, ±2, . . . ).

[0038] By modifying equation (1), the following equation (2) is obtained.

[0039]

[0040] Generally, the effective refractive index is a value between the refractive index of the core and the refractive index of the cladding, so n ｕ－ｃｌａｄ <n ｅｆｆ <n ｃｏｒｅ is satisfied, where n ｃｏｒｅ is the refractive index of the first waveguide core 248. Therefore, the following equation (3) holds:

[0041]

[0042] From equations (2) and (3), m<0 holds, and the order m of the diffracted light by the grating coupler 250 takes a negative value (m=−1, −2, . . . ).

[0043] Generally, it is known that in a grating coupler 250 in which the line width of the recessed portion 251 and the protruding portion 252 is close to 1:1 (Λ=2w, where w is the width of the protruding portion 252), the high-order radiation (m≠-1) is 0 or an extremely small value. Therefore, most (e.g., 90% or more) of the emitted light A1 from such a grating coupler 250 has an emission angle θ that satisfies the following equation (4), which is obtained when m=-1 in equation (1): －１ And then it is emitted.

[0044]

[0045] Hereinafter, for convenience, the emitted light A1 having an order m of −1 emitted from the grating coupler 250 will also be referred to as “−1st order light A11”.

[0046] As shown in Figures 4 and 5, the sending-side optical pins 26 are arranged above the diffraction member 25 (grating coupler 250). The sending-side optical pins 26 are optical waveguides for guiding light A1 emitted from the light source 21 and diffracted by the diffraction member 25 (light emitted from the diffraction member 25). The sending-side optical pins 26 are arranged relatively to the front left in the recess 102 of the substrate 10. The sending-side optical pins (sending-side vertical waveguides) 26 are arranged above the diffraction member 25 (grating coupler 250) and inclined with respect to the top surface 110 of the substrate 10. "The sending-side optical pins 26 are inclined with respect to the top surface 110 of the substrate 10" means that the sending-side vertical waveguide cores (optical pin cores) 268 described below are inclined with respect to the top surface 110 of the substrate 10.

[0047] 5, the sending-side optical pin 26 is disposed on the upper surface of the grating coupler 250 portion of the first waveguide 24. Here, the lower surface of the sending-side optical pin 26 is in contact with the upper surface of the first waveguide 24 (the upper surface of the first waveguide upper clad 2491).

[0048] 2 and 5 , the light-sending optical pin (light-sending vertical waveguide) 26 has a light-sending vertical waveguide core 268 through which light A1 mainly propagates, and a light-sending vertical waveguide clad 269 arranged around the light-sending vertical waveguide core 268. The refractive index of the light-sending vertical waveguide clad 269 is smaller than that of the light-sending vertical waveguide core 268. Note that, for convenience, the light-sending vertical waveguide core 268 will also be referred to as the "optical pin core 268" and the light-sending vertical waveguide clad 269 will also be referred to as the "optical pin clad 269" hereinafter. Also, for convenience, the light-sending vertical waveguide core 268 will also be referred to as the "optical pin clad 269" in FIG. 4 .

[0049] As shown in FIG. 2 , the light-transmitting side optical pin 26 has, for example, a plurality of (here, nine) optical pin cores 268. The optical pin cores 268 are aligned in the same direction (left-right direction) as the plurality of first waveguide cores 248 of the first waveguide 24. The number of optical pin cores 268 may be the same as or greater than the number of first waveguide cores 248. The plurality of optical pin cores 268 may be provided in a number that corresponds to at least each of the plurality of first waveguide cores 248. Here, four of the nine optical pin cores 268 are provided corresponding to the four first waveguide cores 248. Each of the plurality of optical pin cores 268 may be, for example, a rod-shaped rod having a square cross section, a rod-shaped rod having a regular hexagonal cross section, a rod-shaped rod having a circular cross section, or the like. The plurality of optical pin cores 268 extend parallel to each other while being inclined at the same angle relative to the upper surface 110 of the substrate 10.

[0050] 4 and 5, the optical pin core 268 is inclined forward with respect to the normal direction of the upper surface 110 of the substrate 10. The angle β of the optical pin core 268 ｐ (see FIG. 5) is set to an angle suitable for the propagation of the −1st order light A11 from the grating coupler 250. This point will be explained below.

[0051] Generally, from Snell's law, the following equation (5) holds for the light A1 refracted between the first waveguide 24 and the light-sending side optical pin 26.

[0052]

[0053] Here, θ and β1 are the incident angle and the refraction angle (outgoing angle) of the light A1 incident on the optical pin core 268 from the first waveguide upper clad 2491 (see FIG. 5), and n ｐ１ is the refractive index of the optical pin core 268. Here, the incident angle θ is equal to the above-mentioned exit angle θ of the exit light (diffracted light) A1 with respect to the normal N1 of the diffractive member 25.

[0054] When equation (5) is transformed with respect to the refraction angle β1, the following equation (6) is obtained.

[0055]

[0056] In this embodiment, the angle β of the optical pin core 268 ｐ is, for example, the output angle θ in the above formula (4). －１ is set to a value obtained by substituting the angle β of the optical pin core 268 into equation (6). ｐ is set to a value expressed by the following equation (7).

[0057]

[0058] Angle β of the optical pin core 268 ｐ By setting in accordance with equation (7), the −1st order light A11 propagates within the optical pin core 268 along (parallel to) the extension direction of the optical pin core 268. This allows the −1st order light A11 to propagate within the sending-side optical pin 26 with almost no reflection, reducing loss within the sending-side optical pin 26 and improving transmission efficiency.

[0059] In reality, the light A1 incident on the optical pin core 268 from the first waveguide 24 may include not only the above-mentioned −1st-order light A11 but also higher-order (order m=−2, −3, . . . ) diffracted light and light scattered within the first waveguide 24. Light other than the −1st-order light A11 may propagate within the optical pin core 268 in a direction different from the extension direction of the optical pin core 268.

[0060] Generally, the condition (critical angle condition) under which light A12 propagating through the optical pin core 268 is totally reflected at the boundary B1 between the optical pin clad 269 on the front side (left side of Figure 5) and the optical pin core 268 is expressed by the following equation (8).

[0061]

[0062] However, β ｐ is the angle of the optical pin core 268, β ｐ１ is the refraction angle of the light A12 incident on the optical pin core 268 from the first waveguide upper clad 2491, and n ｐ１ is the refractive index of the optical pin core 268, n ｐ２ is the refractive index of the optical pin clad 269.

[0063] Therefore, the condition for light A12 propagating through the optical pin core 268 toward the boundary B1 to be reflected at the boundary B1 and propagate through the optical pin core 268 is expressed by the following equation (9).

[0064]

[0065] Refraction angle β ｐ１ By modifying equation (9) with respect to, the following equation (10) is obtained.

[0066]

[0067] Furthermore, with regard to the boundary B2 between the rear side (right side of Figure 5) of the optical pin clad 269 and the optical pin core 268, the condition for light A13 traveling within the optical pin core 268 toward the boundary B2 to be reflected at the boundary B2 and propagate within the optical pin core 268 is expressed by the following equation (11).

[0068]

[0069] However, β ｐ２ is the refraction angle of the light A13 incident on the optical pin core 268 from the first waveguide upper clad 2491.

[0070] In this way, not only the −1st order light A11 but also other light can propagate through the light-sending-side light pin 26. Therefore, light other than the −1st order light A11 can also be emitted from the light-sending-side light pin 26.

[0071] A method for forming the light-sending side optical pins 26 inclined with respect to the upper surface 110 of the substrate 10 will be briefly described below.

[0072] To form the transmitting optical pins 26, for example, a transparent plate 13 (see FIG. 9 ) is first placed so as to cover the area in the recess 102 of the substrate 10 where the transmitting optical pins 26 are to be formed. The transparent plate 13 is, for example, a glass plate. Next, the space below the transparent plate 13 is filled with resin for forming the optical pin cores 268. Next, a photomask having openings corresponding to the shape of the optical pin cores 268 is placed on the transparent plate 13, and ultraviolet light for curing the resin is irradiated obliquely from above the photomask at a desired angle relative to the normal direction of the upper surface of the transparent plate 13 to harden the resin, thereby forming the optical pin cores 268. Next, after removing the unhardened resin, a resin for forming the optical pin clads 269 is filled, and the filled resin is photo-hardened. This allows the transmitting optical pins 26 to be formed. The optical chip 1 including the transmitting optical pins 26 thus formed includes a transparent plate 13 (see FIG. 9 ) covering the transmitting optical pins 26. The upper surface of the light-sending side light pin 26 is in contact with the transparent plate 13 .

[0073] In the optical chip 1, light A1 emitted from the light source 21 propagates through the first waveguide 24, is diffracted by the grating coupler 250, propagates through the light-sending side optical pin 26, and is emitted to the outside of the optical chip 1 from the top surface of the light-sending side optical pin 26.

[0074] (1.3.2) Configuration of the Light-Receiving Side As shown in FIG. 6 , the light-receiving component 31 is disposed on the upper surface 110 of the substrate 10. The light-receiving component 31 is disposed in the recess 102 of the substrate 10. The light-receiving component 31 is disposed in a relatively front right position within the recess 102 of the substrate 10. The light-receiving component 31 is a surface-receiving element. The light-receiving component 31 is embedded in the upper surface 110 of the substrate 10 (the bottom surface 111 of the recess 102) so that the light-receiving surface is exposed upward.

[0075] The light receiving component 31 receives the light A2 and generates an electrical signal corresponding to the received light A2. The light receiving component 31 is, for example, a photodiode. Specific examples of the light receiving component 31 include a PIN photodiode and an avalanche photodiode. The photodiode serving as the light receiving component 31 can be formed, for example, by epitaxially growing germanium (Ge) directly on a silicon substrate.

[0076] 2 and 6, the light-receiving side waveguide 33 includes a light-receiving side vertical waveguide 34. For convenience, the light-receiving side vertical waveguide 34 will also be referred to as a "light-receiving side optical pin 34" below.

[0077] The light-receiving side optical pin 34 is disposed above the light-receiving component 31. The light-receiving side optical pin 34 is an optical waveguide for guiding light A2 from the optical fiber 91. The light-receiving side optical pin (light-receiving side vertical waveguide) 34 is disposed above the light-receiving component 31 and inclined with respect to the upper surface 110 of the substrate 10. "The light-receiving side optical pin 34 is inclined with respect to the upper surface 110 of the substrate 10" means that a light-receiving side vertical waveguide core (optical pin core) 348, which will be described later, is inclined with respect to the upper surface 110 of the substrate 10.

[0078] As shown in Fig. 6, the light-receiving-side light pins 34 are arranged on the upper surface of the light-receiving component 31. Here, the lower surfaces of the light-receiving-side light pins 34 are in contact with the upper surface of the light-receiving component 31. As shown in Fig. 2, the light-receiving-side light pins 34 are arranged alongside the light-sending-side light pins 26 in the left-right direction.

[0079] As shown in Figures 2 and 6, the light-receiving side optical pin (light-receiving side vertical waveguide) 34 has a light-receiving side vertical waveguide core 348 through which light A2 mainly propagates, and a light-receiving side vertical waveguide clad 349 arranged around the light-receiving side vertical waveguide core 348. The refractive index of the light-receiving side vertical waveguide clad 349 is smaller than the refractive index of the light-receiving side vertical waveguide core 348. Note that, for convenience, the light-receiving side vertical waveguide core 348 will also be referred to as the "optical pin core 348," and the light-receiving side vertical waveguide clad 349 will also be referred to as the "optical pin clad 349." Also, for convenience, the optical pin clad 269 is not shown in Figure 6.

[0080] 2 , the light-receiving side optical pin 34 has, for example, a plurality of (here, nine) optical pin cores 348. Here, the plurality of optical pin cores 348 are aligned along the direction (left-right direction) in which the plurality of optical pin cores 268 are aligned. Each of the plurality of optical pin cores 348 may be, for example, a rod-shaped one having a square cross section, a rod-shaped one having a regular hexagonal cross section, a rod-shaped one having a circular cross section, or the like. The plurality of optical pin cores 348 extend parallel to one another while being inclined at the same angle relative to the upper surface 110 of the substrate 10.

[0081] The receiving-side optical pins 34 are formed, for example, at the same time as the transmitting-side optical pins 26 using the same formation procedure as the transmitting-side optical pins 26. This simplifies the manufacturing procedure for the optical chip 1 compared to when the transmitting-side optical pins 26 and the receiving-side optical pins 34 are formed separately. Because the receiving-side optical pins 34 are formed at the same time using the same formation procedure as the transmitting-side optical pins 26, the inclination angle of the receiving-side optical pins 34 (the inclination angle of the optical pin cores 348) is the same as the inclination angle of the transmitting-side optical pins 26 (the inclination angle of the optical pin cores 268). Furthermore, like the transmitting-side optical pins 26, the receiving-side optical pins 34 are also covered by the transparent plate 13. The top surfaces of the receiving-side optical pins 34 are in contact with the transparent plate 13.

[0082] Light A2 incident on the upper surface of the light-receiving side optical pin 34 from the outside propagates through the light-receiving side optical pin 34 and is incident on the light-receiving surface of the light-receiving component 31 .

[0083] The light-receiving circuit 32 is electrically connected to a terminal 101 of the substrate 10 (e.g., a terminal 101 different from the terminal 101 to which the light-transmitting circuit 22 is connected). As shown in FIGS. 2 and 6 , the light-receiving circuit 32 includes a receiver IC 321. The receiver IC 321 is disposed on the upper surface 110 of the substrate 10. The light-receiving circuit 32 has, for example, a function of amplifying an electrical signal from the light-receiving component 31 and a function of transmitting the electrical signal to an external electrical device via the terminal 101.

[0084] (1.4) Optical Member The optical member 4 is a member for optically connecting the optical chip 1 and the optical fiber cable 9. The optical member 4 is optically coupled to the optical chip 1 and the optical fiber cable 9.

[0085] The optical member 4 transmits the light A1 from the optical chip 1 to the optical fiber cable 9. As shown in FIG. 4 , the optical member 4 transmits the light A1 from the light-transmitting side optical pin 26 of the optical chip 1 to the optical fiber 91 of the optical fiber cable 9.

[0086] 6, the optical member 4 transmits the light A2 from the optical fiber cable 9 to the optical chip 1. As shown in FIG.

[0087] As shown in FIGS. 4 and 6, the optical member 4 includes an optical bench 5 and a refractive member 6.

[0088] (1.4.1) Optical Bench As shown in Fig. 3, the optical bench 5 has a bench substrate 51, a bench waveguide 52, a mirror 55 (see Figs. 4 and 6), and a fiber holder 56. The optical bench 5 is disposed above the light-sending-side optical pins (light-sending-side vertical waveguides) 26 of the optical chip 1. The optical bench 5 is also disposed above the light-receiving-side optical pins (light-receiving-side vertical waveguides) 34 of the optical chip 1.

[0089] The bench substrate 51 is, for example, a rectangular plate in a plan view. The optical bench 5 is disposed above the optical chip 1 so that the lower surface of the bench substrate 51 faces the upper surfaces of the light-sending side optical pins 26 and the light-receiving side optical pins 34 of the optical chip 1.

[0090] The bench substrate 51 is formed of, for example, a silicon substrate. That is, the optical bench 5 is a silicon bench. By forming a large number of bench substrates 51 on a silicon wafer and dicing the formed silicon wafer, the optical benches 5 can be easily mass-produced.

[0091] As shown in Figure 3, the underside of the bench substrate 51 is formed with a recess 511 for arranging the tips (rear ends) of multiple optical fibers 91 of the optical fiber cable 9, and a groove 512 for arranging the bench waveguide 52.

[0092] The recess 511 is formed in a rectangular shape recessed upward in a relatively front portion of the lower surface of the bench substrate 51. The front end of the recess 511 reaches the front end of the bench substrate 51.

[0093] The groove 512 is connected to the rear end of the recess 511 and extends in the front-to-rear direction of the bench substrate 51. However, the rear end of the groove 512 does not reach the rear end of the bench substrate 51. The left and right sides of the groove 512 are inclined surfaces that are inclined so that the width of the groove 512 narrows from bottom to top. The rear side of the groove 512 is an inclined surface that slopes forward (see FIGS. 4 and 6 ). Each side of the groove 512 is inclined at an angle of 45° with respect to the bottom surface of the bench substrate 51, for example. Note that the inclination angle of each side of the groove 512 with respect to the bottom surface of the bench substrate 51 is not limited to 45° and may be other angles such as 35.3°, 54.7°, etc.

[0094] 3, a plurality of grooves 512 (eight in this example) are formed on the lower surface of the bench substrate 51. The grooves 512 extend parallel to one another from the rear end of the recess 511 rearward.

[0095] The recess 511 and the plurality of grooves 512 are formed by etching the silicon substrate, which allows the recess 511 and the plurality of grooves 512 to be formed with high precision.

[0096] The mirror 55 is provided on the bench substrate 51. The mirror 55 is, for example, a metal film. As shown in FIGS. 4 and 6 , the mirror 55 is provided on the rear side of the groove 512 in the bench substrate 51. The mirror 55 is inclined so that its normal direction faces diagonally downward. The inclination angle of the mirror 55 (the inclination angle with respect to the underside of the bench substrate 51) is the same as the inclination angle of the rear side of the groove 512. This allows the inclination angle of the mirror 55 to be set with high precision. A mirror 55 is provided on the rear side of each of the multiple grooves 512.

[0097] The bench waveguide 52 is provided on the bench substrate 51. The bench waveguide 52 is disposed below the bench substrate 51.

[0098] The optical bench 5 includes, for example, a plurality of (here, eight) bench waveguides 52 .

[0099] The bench waveguides 52 are respectively arranged in the grooves 512 in the lower surface of the bench substrate 51. The bench waveguides 52 extend parallel to each other in the front-rear direction along the lower surface of the bench substrate 51.

[0100] The groove 512 of the bench substrate 51 is formed, for example, so that the depth of the groove 512 is equal to the vertical height of the bench waveguide 52. As a result, with the bench waveguide 52 accommodated in the groove 512, the bottom surface of the bench waveguide 52 coincides with the bottom surface of the bench substrate 51.

[0101] 3, the plurality of bench waveguides 52 include at least one (four in this example) light-transmitting-side bench waveguide 53 and at least one (four in this example) light-receiving-side bench waveguide 54. For convenience, hereinafter, the light-transmitting-side bench waveguide 53 will also be referred to as the "second waveguide 53," and the light-receiving-side bench waveguide 54 will also be referred to as the "waveguide 54."

[0102] As shown in FIG. 4, the light-sending bench waveguide (second waveguide) 53 is an optical waveguide for guiding the light A1 emitted from the light-sending optical pin 26.

[0103] 3 , the optical bench 5 includes a plurality of second waveguides 53. The number of second waveguides 53 is, for example, the same as the number of light-sending-side vertical waveguide cores (optical pin cores) 268, but is not limited to this and may be different. The plurality of second waveguides 53 should be provided in a number that corresponds to at least each of the plurality of optical pin cores 268. Here, four second waveguides 53 are provided so as to correspond to the four optical pin cores 268, respectively.

[0104] 4, the second waveguide (light-sending side bench waveguide) 53 has a light-sending side bench waveguide core 538 through which light A1 mainly propagates, and a light-sending side bench waveguide clad 539 arranged around the light-sending side bench waveguide core 538. The refractive index of the light-sending side bench waveguide clad 539 is smaller than the refractive index of the light-sending side bench waveguide core 538. For convenience, hereinafter, the light-sending side bench waveguide core 538 will also be referred to as the "second waveguide core 538," and the light-sending side bench waveguide clad 539 will also be referred to as the "second waveguide clad 539."

[0105] The second waveguide core 538 may be, for example, a rod-shaped one having a square cross section, a rod-shaped one having a regular hexagonal cross section, or a rod-shaped one having a circular cross section. The rear end of the second waveguide core 538 is inclined at the same angle as the inclination angle of the mirror 55 provided in the groove 512. For convenience, the mirror 55 provided in the groove 512 in which the second waveguide 53 is disposed, among the multiple mirrors 55, will hereinafter also be referred to as the "light-sending-side mirror 551." The rear end of the second waveguide core 538 is in contact with the light-sending-side mirror 551.

[0106] The second waveguide clad 539 is disposed below the second waveguide core 538. The second waveguide clad 539 is in contact with the lower surface of the second waveguide core 538.

[0107] As shown in FIG. 4 , in the second waveguide 53, light A1 incident on the lower surface of the second waveguide clad 539 from below is reflected forward by the light-sending side mirror 551, propagates forward within the second waveguide core 538, and can be output to the optical fiber 91 from the front end face of the second waveguide 53.

[0108] The second waveguide 53 may also include the second waveguide clad 539 at a position other than below the second waveguide core 538. The position other than below the second waveguide core 538 may be, for example, above or to the side (left or right) of the second waveguide core 538. The side surface (periphery) of the second waveguide core 538 may be surrounded by the second waveguide clad 539.

[0109] As shown in FIG. 6, the light-receiving bench waveguide (waveguide) 54 is an optical waveguide for guiding light A2 from an optical fiber 91.

[0110] 3, the optical bench 5 includes a plurality of waveguides 54. The number of waveguides 54 is, for example, the same as the number of light-receiving-side vertical waveguide cores (optical pin cores) 348, but is not limited to this and may be different. The plurality of waveguides 54 should be provided in a number that corresponds to at least each of the plurality of optical pin cores 348. Here, four waveguides 54 are provided so as to correspond to the four optical pin cores 348, respectively.

[0111] 6 , the waveguide (receiving-side bench waveguide) 54 has a receiving-side bench waveguide core 548 through which light A2 mainly propagates, and a receiving-side bench waveguide clad 549 arranged around the receiving-side bench waveguide core 548. The refractive index of the receiving-side bench waveguide clad 549 is smaller than the refractive index of the receiving-side bench waveguide core 548. Note that, for convenience, hereinafter the receiving-side bench waveguide core 548 will also be referred to as the "waveguide core 548," and the receiving-side bench waveguide clad 549 will also be referred to as the "waveguide clad 549."

[0112] The waveguide core 548 may be, for example, a rod-shaped one with a square cross section, a rod-shaped one with a regular hexagonal cross section, or a rod-shaped one with a circular cross section. The rear end of the waveguide core 548 is inclined at the same angle as the inclination angle of the mirror 55 provided in the groove 512. For convenience, the mirror 55 provided in the groove 512 in which the waveguide 54 is disposed, out of the multiple mirrors 55, will hereinafter also be referred to as the "receiving-side mirror 552." The rear end of the waveguide core 548 is in contact with the receiving-side mirror 552.

[0113] The waveguide clad 549 is disposed at least above and below the plurality of waveguide cores 548. The waveguide clad 549 contacts the upper and lower surfaces of the plurality of waveguide cores 548.

[0114] As shown in FIG. 6 , in the waveguide 54, light A2 incident from the optical fiber 91 onto the front end face of the waveguide core 548 is propagated backward within the waveguide core 548, reflected downward by the light-receiving side mirror 552, and emitted downward from the lower surface of the waveguide clad 549.

[0115] The waveguide 54 may also include a waveguide clad 549 at a position other than above and below the waveguide core 548. The position other than above and below the waveguide core 548 may be, for example, a side (left or right) of the waveguide core 548. The side surface (periphery) of the waveguide core 548 may be surrounded by the waveguide clad 549.

[0116] Here, the conditions for the light A2 from the optical fiber 91 to propagate through the waveguide 54 include the following equations (12) and (13), based on the condition that the light A2 is reflected at the boundary between the waveguide core 548 and the waveguide clad 549.

[0117]

[0118] However, ρ １ is the angle formed between the lower waveguide clad 549 and the light A2 when the light A2 is reflected by the lower waveguide clad 549, and ρ ２ is the angle formed between the upper waveguide clad 549 and the light A2 when the light A2 is reflected by the upper waveguide clad 549 (see FIG. 7). ３ , n ４ , n ５ are the refractive indices of the lower waveguide cladding 549, the waveguide core 548, and the upper waveguide cladding 549, respectively.

[0119] As shown in FIG. 3, the fiber holding portion 56 has an adjustment structure 561 , a fixing portion 562 , a holding substrate 563 , and a cable holding member 564 .

[0120] The adjustment structure 561 is formed in a recess 511 on the underside of the bench substrate 51. The adjustment structure 561 includes a plurality of protruding ribs extending parallel to each other in the front-rear direction inside the recess 511. A groove extending in the front-rear direction is formed between two adjacent protruding ribs. An optical fiber 91 of the optical fiber cable 9 can be placed in this groove. The groove of the adjustment structure 561 is connected to a groove 512 of the bench substrate 51 in the front-rear direction. Therefore, by placing the optical fiber 91 in the groove of the adjustment structure 561, the bench waveguide 52 and the optical fiber 91 placed in the groove 512 face each other and are optically coupled.

[0121] The fixing portion 562 has a plate shape (rectangular parallelepiped shape) that is long in the left-right direction. The fixing portion 562 is fixed to the lower surface of the bench substrate 51. With the optical fiber 91 placed in the groove of the adjustment structure 561, the fixing portion 562 is fixed to the bench substrate 51, whereby the optical fiber 91 is fixed in position relative to the bench substrate 51.

[0122] The holding substrate 563 is a rectangular plate and is fixed to the upper surface of the bench substrate 51. The front end of the holding substrate 563 protrudes forward beyond the front end of the bench substrate 51.

[0123] The cable holding member 564 holds the optical fiber cable 9. The cable holding member 564 is provided on the underside of the holding substrate 563 in a portion exposed from the bench substrate 51. The cable holding member 564 has a through-hole penetrating in the front-to-rear direction. The optical fiber cable 9 is passed through the through-hole, whereby the optical fiber cable 9 is held by the cable holding member 564. Since the optical bench 5 has the cable holding member 564, it is easy to position the optical fiber cable 9 relative to the optical bench 5, and the optical fiber 91 can be easily optically coupled to the bench waveguide 52. Note that instead of using the cable holding member 564, an adhesive may be used to adhesively fix the optical fiber cable 9 to the holding substrate 563, so that the fiber holding unit 56 holds the optical fiber cable 9.

[0124] (1.4.2) Refractive Member As shown in FIGS. 4 and 6, the refractive member 6 is disposed between the optical chip 1 and the optical bench 5.

[0125] The refractive member 6 adjusts the angle of incidence of the light A1 emitted from the light-sending vertical waveguide (light-sending optical pin) 26 of the optical chip 1 onto the light-sending bench waveguide (second waveguide) 53 of the optical bench 5.

[0126] That is, within second waveguide 53, the traveling direction of light A1 after being reflected by light-sending-side mirror 551 is determined by the angle of incidence of this light A1 on light-sending-side mirror 551. If the traveling direction of light A1 after being reflected by light-sending-side mirror 551 is significantly inclined with respect to the extension direction of second waveguide 53, light A1 may reach the boundary between second waveguide core 538 and bench substrate 51 or the boundary between second waveguide core 538 and second waveguide clad 539, and the intensity of light A1 may be attenuated.

[0127] 4 , the refractive member 6 of this embodiment is disposed between the optical bench 5 and the light-sending vertical waveguide (light-sending optical pin) 26. The refractive member 6 refracts the light A1 emitted from the light-sending optical pin 26 and adjusts the angle of incidence of this light A1 on the light-sending mirror 551. This reduces the angle between the traveling direction of the light A1 after reflection from the light-sending mirror 551 and the extension direction of the second waveguide 53 (making the traveling direction of the light A1 closer to parallel to the extension direction of the second waveguide 53), thereby suppressing attenuation of the light A1. This improves the transmission efficiency of the light A1 in the optical module 100.

[0128] In addition, the refractive member 6 adjusts the angle of incidence of light A2 emitted from the receiving side bench waveguide (waveguide) 54 of the optical bench 5 to the receiving side vertical waveguide (receiving side optical pin) 34 of the optical chip 1.

[0129] That is, the traveling direction of the light A2 inside the light-receiving side optical pin 34 is determined by the incident angle of the light A2 onto the light-receiving side optical pin 34. If the traveling direction of the light A2 is significantly inclined with respect to the extension direction of the light-receiving side optical pin 34, the light A2 may reach the boundary between the optical pin core 348 and the optical pin clad 349, and the intensity of the light A2 may be attenuated.

[0130] 6 , the refractive member 6 of this embodiment is disposed between the optical bench 5 and the receiving-side vertical waveguide (receiving-side optical pin) 34. The refractive member 6 refracts the light A2 emitted from the waveguide 54 and adjusts the angle of incidence of this light A2 on the receiving-side optical pin 34. This reduces the angle between the traveling direction of the light A2 within the receiving-side optical pin 34 and the extension direction of the receiving-side optical pin 34 (making the traveling direction of the light A2 closer to parallel to the extension direction of the receiving-side optical pin 34), thereby suppressing attenuation of the light A2. This improves the transmission efficiency of the light A2 in the optical module 100.

[0131] The refractive member 6 will be described in more detail below with reference to the drawings.

[0132] 8, the refractive member 6 is in the shape of a rectangular flat plate. The refractive member 6 is attached to the optical bench 5 so as to face the lower surface of the optical bench 5, for example. As shown in FIGS. 4 and 6, a lower surface 608 of the refractive member 6 contacts the optical chip 1, and an upper surface 609 of the refractive member 6 contacts the optical bench 5.

[0133] As shown in FIG. 9 , the refractive member 6 has a main body portion 601 and a refractive portion 602 .

[0134] The main body 601 has a rectangular plate shape. The main body 601 is made of a material that is transparent to the lights A1 and A2. The material of the main body 601 can be selected from, for example, glass, optically transparent resin (acrylic, epoxy, silicone, polycarbonate, polyetherimide, polystyrene, polyolefin, fluorine, polyimide, phenol, polyester, polysilane, polynorbornene, etc.), etc.

[0135] 8, the main body 601 of the refractive member 6 has a recess 60 provided on a lower surface 608. That is, the main body 601 is provided with the recess 60.

[0136] 8, the recess 60 includes a first recess 61 and a second recess 62. The first recess 61 and the second recess 62 are provided at different positions in the main body 601.

[0137] As shown in FIG. 8 , the first recess 61 is provided on the lower surface of the main body 601 at a relatively left position. The first recess 61 is a groove extending in the left-right direction. As shown in FIG. 4 , the first recess 61 is provided, for example, on the lower surface of the main body 601 at a position below the sending-side mirror 551 when the refractive member 6 is attached to the optical bench 5. The first recess 61 is located between the sending-side vertical waveguide (sending-side optical pin) 26 of the optical chip 1 and the sending-side bench waveguide (second waveguide) 53 of the optical bench 5 when the refractive member 6 is disposed between the optical chip 1 and the optical bench 5. In this way, the refractive member 6 has a recess (first recess 61) provided on the surface (lower surface 608) facing the sending-side vertical waveguide (sending-side optical pin) 26.

[0138] As shown in FIG. 8 , the second recess 62 is provided on the lower surface of the main body 601 at a relatively right position. The second recess 62 is a groove extending in the left-right direction. As shown in FIG. 6 , the second recess 62 is provided, for example, on the lower surface of the main body 601 at a position below the receiving-side mirror 552 when the refractive member 6 is attached to the optical bench 5. The second recess 62 is located between the receiving-side bench waveguide (waveguide) 54 of the optical bench 5 and the receiving-side vertical waveguide (receiving-side optical pin) 34 of the optical chip 1 when the refractive member 6 is disposed between the optical chip 1 and the optical bench 5. In this way, the refractive member 6 has a recess (second recess 62) provided on the surface (lower surface 608) facing the receiving-side vertical waveguide (receiving-side optical pin) 34.

[0139] In the optical module 100 of this embodiment, the light-sending side optical pins 26 and the light-receiving side optical pins 34 are arranged side by side in the left-right direction. Therefore, the first recess 61 and the second recess 62 provided in the refractive member 6 are connected in the left-right direction to form a single groove-shaped recess 60 extending in the left-right direction.

[0140] The refractive portion 602 is located inside the recess 60. The refractive portion 602 is formed from a material that is transparent to the light A1 and A2. The material of the refractive portion 602 can be selected from, for example, glass, optically transparent resin (acrylic, epoxy, silicone, polycarbonate, polyetherimide, polystyrene, polyolefin, fluorine, polyimide, phenol, polyester, polysilane, polynorbornene, etc.), etc. However, a material different from that of the main body portion 601 is selected for the refractive portion 602. The refractive portion 602 and the main body portion 601 have different refractive indices.

[0141] The material of the refraction portion 602 may be air, that is, the refraction portion 602 may be an air layer.

[0142] (1.4.2.1) First Recess As shown in FIGS. 4 and 8, the first recess 61 is formed in the shape of a groove having a triangular cross section.

[0143] 8 to 10 , the inner surface of the first recess 61 of the refractive member 6 includes a first surface 611 located below the light-sending side mirror 551. The first surface 611 is inclined with respect to the upper surface 110 of the substrate 10 (the bottom surface 111 of the recess 102). The first surface 611 is a flat surface.

[0144] The inner surface of the first recess 61 of the refractive member 6 further includes a second surface 612 located below the light-sending side mirror 551. The second surface 612 is a flat surface. In a cross-sectional view (a cross-section perpendicular to the left-right direction), the first recess 61 is surrounded by the first surface 611 and the second surface 612. The second surface 612 may or may not overlap the light-sending side mirror 551 in the vertical direction.

[0145] In the refractive member 6 of this embodiment, the first surface 611 of the first recess 61 is an inclined surface inclined at an inclination angle α (see FIGS. 9 and 10 ) with respect to the lower surface 608 of the refractive member 6 so that the normal direction faces diagonally downward and forward. Furthermore, the second surface 612 of the first recess 61 is perpendicular to the lower surface 608 of the refractive member 6. In other words, the first recess 61 has a cross section in the shape of a right triangle. However, this is not a limitation, and the second surface 612 of the first recess 61 may also be inclined with respect to the lower surface 608 of the refractive member 6.

[0146] In this way, since the first recess 61 includes the first surface 611, the light A1 incident on the refractive member 6 from the light-sending side light pin 26 can be refracted by the first surface 611 and incident on the second waveguide 53 at the desired angle.

[0147] 9 and 10 , conditions for propagating light A1 within second waveguide 53 along the extension direction of second waveguide 53 (parallel to the extension direction) in optical module 100 will be described. When light A1 propagates along the extension direction of second waveguide 53, it is most unlikely that light A1 will reach the boundary of second waveguide core 538. In other words, when light A1 propagates along this direction, attenuation of light A1 in second waveguide 53 can be most suppressed.

[0148] As explained in the section "(1.2.1) Configuration of the Light-Sending Side," light other than the −1st-order light A11 is also emitted from the light-sending-side optical pins 26. However, most (e.g., 90% or more) of the light A1 emitted from the light-sending-side optical pins 26 is the −1st-order light A11. Therefore, the following describes the conditions for propagating this −1st-order light A11 within the second waveguide 53 along the extension direction of the second waveguide 53.

[0149] As described above, the −1st order light A11 passes through the light-sending side optical pin 26 (inside the optical pin core 268) at an angle β ｐ 9 and 10 , the −1st order light A11 passes through the transparent plate 13, the refraction section 602, the main body section 601, and the second waveguide clad 539 in this order, enters the second waveguide core 538, is reflected by the light-sending side mirror 551, and propagates within the second waveguide core 538.

[0150] Here, when the −1st order light A11 propagates from the refraction portion 602 to the main body portion 601, the inclination angle α of the first surface 611 of the first recess 61, the refractive index n ２ , the refractive index n of the refractive portion 602 １ Depending on the above, there may be a case where the light is refracted forward with respect to the normal to the upper surface 110 of the substrate 10 as shown in FIG. 9 (hereinafter also referred to as the "first case"), or a case where the light is refracted backward with respect to the normal to the upper surface 110 of the substrate 10 as shown in FIG. 10 (hereinafter also referred to as the "second case").

[0151] In the first case (θ ｏ ≧α, see FIG. 9), the following equations (14) to (18) hold true from Snell's law.

[0152]

[0153] Here, δ is the refraction angle of the light A11 incident from the optical pin core 268 to the transparent plate 13 and the incident angle of the light A11 incident from the transparent plate 13 to the refraction portion 602, β is the refraction angle of the light A11 incident from the transparent plate 13 to the refraction portion 602, and θ ｉ is the angle of incidence of the light A11 incident on the main body 601 from the refraction portion 602, and θ ｏ is the refraction angle of the light A11 incident on the main body 601 from the refraction portion 602, and θ １is the incident angle of the light A11 incident from the main body 601 to the second waveguide clad 539, and θ ２ is the refraction angle of the light A11 incident from the main body 601 to the second waveguide clad 539 and the incident angle of the light A11 incident from the second waveguide clad 539 to the second waveguide core 538, θ ３ is the refraction angle of the light A11 incident from the second waveguide clad 539 to the second waveguide core 538. Ｇ , n ３ , n ４ are the refractive indices of the transparent plate 13, the second waveguide clad 539, and the second waveguide core 538, respectively.

[0154] Furthermore, due to the relationship between angles, the following equations (19) and (20) hold true.

[0155]

[0156] The condition for reflecting the light A11 by the light-sending side mirror 551 along (parallel to) the extending direction of the second waveguide 53 is expressed by the following equation (21).

[0157]

[0158] Here, γ is the tilt angle of the light-sending side mirror 551 with respect to the upper surface 110 of the substrate 10 (see FIG. 9).

[0159] From equations (14) and (15), the following equation (22) is obtained.

[0160]

[0161] Furthermore, the following formula (23) can be obtained from formulas (16) and (19), the following formula (24) can be obtained from formulas (17) and (20), and the following formula (25) can be obtained from formulas (18) and (21).

[0162]

[0163] When equations (22) to (25) are transformed with respect to γ, the following equation (26) is obtained.

[0164]

[0165] In addition, the first case is the condition θ ｏ≧α is expressed by the following equation (27).

[0166]

[0167] In the second case (θ ｏ <α, see FIG. 10), equations (14) to (18) and equation (22) hold true from Snell's law, just like in the first case.

[0168] Furthermore, due to the relationship between angles, the following equations (28) and (29) hold true.

[0169]

[0170] The condition for reflecting the light A11 by the light-sending side mirror 551 along (parallel to) the extending direction of the second waveguide 53 is expressed by the following equation (30).

[0171]

[0172] The following equation (31) is obtained from equations (16) and (28), the following equation (32) is obtained from equations (17) and (29), and the following equation (33) is obtained from equations (18) and (30).

[0173]

[0174] When equations (22) and (31) to (33) are transformed with respect to γ, the following equation (34) is obtained.

[0175]

[0176] In addition, the second case is the condition θ ｏ <α is expressed by the following equation (35).

[0177]

[0178] By designing the material and inclination angle α of the refractive member 6 (main body portion 601 and refractive portion 602) so that the above equations (26) and (27) are satisfied, or so that the above equations (34) and (35) are satisfied, a refractive member 6 having the desired first recess 61 can be obtained.

[0179] As shown in Figures 9 and 10, the front-rear width of the first surface 611 of the first recess 61 of the refractive member 6 is greater than the front-rear width of the sending-side vertical waveguide (sending-side optical pin) 26. The "front-rear width of the first surface 611 of the first recess 61 of the refractive member 6" refers to the dimension of the first surface 611 along a direction perpendicular to the vertical direction (front-rear direction) in a cross section including the normal direction (downward diagonal front) and the vertical direction of the sending-side mirror 551. The "front-rear width of the sending-side optical pin 26" refers to the dimension of the sending-side optical pin 26 along a direction perpendicular to the vertical direction (front-rear direction) in a cross section including the normal direction (downward diagonal front) and the vertical direction of the sending-side mirror 551. The "width of the sending-side optical pin 26" refers to the width of the upper surface of the optical pin core 268. If the upper surface of the optical pin core 268 is circular, for example, the "width of the sending-side optical pin 26" refers to the maximum width of the upper surface of the optical pin core 268. This makes it difficult for light A1 emitted from the light-sending-side light pin 26 to deviate from the first recess 61. Furthermore, even if the refractive member 6 is positioned relatively forward or backward from the light-sending-side light pin 26, light A1 emitted from the light-sending-side light pin 26 is easily received by the first recess 61. In short, this configuration has the advantage that light A1 from the light-sending-side light pin 26 is less likely to escape.

[0180] 9 and 10 , the width in the front-to-rear direction of the light sending side mirror 551 is larger than the width in the front-to-rear direction of the light sending side vertical waveguide (light sending side optical pin) 26. Note that the "width in the front-to-rear direction of the light sending side mirror 551" refers to the dimension of the light sending side mirror 551 along a direction (front-to-rear direction) perpendicular to the up-to-down direction in a cross section including the normal direction (diagonally downward front) and the up-to-down direction of the light sending side mirror 551. This makes it difficult for light A1 emitted from the light sending side optical pin 26 to deviate from the light sending side mirror 551. In short, this configuration has the advantage of making it difficult for light A1 from the light sending side optical pin 26 to escape.

[0181] 9 and 10, the inclination angle β of the light-sending vertical waveguide (light-sending optical pin) 26 with respect to the substrate 10 ｑ１is larger than the inclination angle γ of the light-sending side mirror 551 with respect to the substrate 10. This reduces the angle of the light A1 that needs to be refracted by the refractive member 6, thereby reducing the loss of the light A1 when it passes through the refractive member 6. Note that the inclination angle β of the light-sending side optical pin 26 with respect to the substrate 10 ｑ１ Here, is the angle formed by a line connecting the center of gravity of the upper surface of the light-sending side light pin 26 (the center in the case of a circle) and the center of gravity of the lower surface, and the upper surface 110 of the substrate 10. In this embodiment, the inclination angle β of the light-sending side light pin 26 with respect to the substrate 10 is ｑ１ The magnitude of is 90°-β ｐ It is expressed as:

[0182] (1.4.2.2) Second Recess As shown in FIGS. 6 and 8, the second recess 62 is formed in the shape of a groove having a triangular cross section.

[0183] 8 , the inner surface of the second recess 62 of the refractive member 6 includes a first surface 621 located below the light-receiving side mirror 552. The first surface 621 is inclined with respect to the upper surface 110 of the substrate 10 (the bottom surface 111 of the recess 102). The first surface 621 is a flat surface.

[0184] The inner surface of the second recess 62 of the refractive member 6 further includes a second surface 622 located below the light-receiving side mirror 552. The second surface 622 is flat. In a cross-sectional view (a cross section perpendicular to the left-right direction), the second recess 62 is surrounded by the first surface 621 and the second surface 622. The second surface 622 may or may not overlap with the light-receiving side mirror 552 in the vertical direction.

[0185] In the refractive member 6 of this embodiment, the first surface 621 of the second recess 62 is an inclined surface inclined at an inclination angle α with respect to the lower surface 608 of the refractive member 6 so that the normal direction faces diagonally downward and forward. Furthermore, the second surface 622 of the second recess 62 is perpendicular to the lower surface 608 of the refractive member 6. In other words, the second recess 62 has a cross section in the shape of a right triangle. However, this is not a limitation, and the second surface 622 of the second recess 62 may also be inclined with respect to the lower surface 608 of the refractive member 6.

[0186] In this way, since the second recess 62 includes the first surface 621, the light A2 incident on the refractive member 6 from the waveguide 54 can be refracted by the first surface 621 and incident on the light receiving side optical pin 34 at the desired angle.

[0187] Although detailed description will be omitted, light A2 propagating in the receiving-side bench waveguide (waveguide) 54 along the extending direction of the waveguide 54 is reflected by the receiving-side mirror 552 and passes through the refractive member 6, and is incident at an angle β ｐ The conditions for propagation in the receiving-side vertical waveguide (receiving-side optical pin) 34 along the extension direction of the receiving-side optical pin 34 that is inclined at α are also expressed by equations (26) and (27), or equations (34) and (35). Therefore, by designing the material and inclination angle α of the refractive member 6 (main body portion 601 and refractive portion 602) so as to satisfy these conditions, a refractive member 6 having a desired second recess 62 can be obtained.

[0188] As in the case of the light-sending vertical waveguide (light-sending optical pin) 26, the light-receiving vertical waveguide (light-receiving optical pin) 34 has an inclination angle β ｑ１ is larger than the inclination angle γ of the light-receiving side mirror 552 with respect to the substrate 10. This reduces the angle of the light A2 that needs to be refracted by the refractive member 6, thereby reducing the loss of the light A2 when it passes through the refractive member 6. Note that the inclination angle β of the light-receiving side optical pin 34 with respect to the substrate 10 ｑ１ Here, is the angle formed by a line connecting the center of gravity of the upper surface (or the center in the case of a circle) of the light-receiving side optical pin 34 and the center of gravity of the lower surface, and the upper surface 110 of the substrate 10. In this embodiment, the inclination angle β of the light-receiving side optical pin 34 with respect to the substrate 10 ｑ１ The magnitude of is 90°-β ｐ It is expressed as:

[0189] (1.4.2.3) Extension Portion As shown in FIG. 8 , the main body 601 includes a portion 603 (hereinafter also referred to as the "extension portion") that does not face the mirror 55 in the vertical direction. The extension portion 603 extends forward from the portion of the main body 601 where the recess 60 is provided. The upper surface of the extension portion 603 is flat. When the refractive member 6 is attached to the optical bench 5, the extension portion 603 contacts the lower surface of the bench waveguide clad (the second waveguide clad 539 and the waveguide clad 549) of the bench waveguide 52. As a result, a portion of the light A1 may be reflected by the refractive member 6 (extension portion 603) after being reflected by the transmitting-side mirror 551. Furthermore, a portion of the light A2 may be reflected by the receiving-side mirror 552 after being reflected by the refractive member 6 (extension portion 603).

[0190] In this way, since the refractive element 6 has the extension portion 603, it is possible to reflect a portion of the light A1 and A2 at the extension portion 603 and propagate through the bench waveguide 52, thereby making it possible to suppress light loss in the optical element 4.

[0191] (1.4.3) Summary of Optical Elements As described above, the optical element 4 is used together with the optical chip 1 that emits light A1. The optical element 4 includes an optical bench 5 and a refractive element 6. The optical bench 5 has a mirror 55 (light-sending mirror 551) and is disposed above the light-sending pins 26 of the optical chip 1. The refractive element 6 is disposed between the optical bench 5 and the light-sending pins 26. The refractive element 6 has a recess 60 (first recess 61) provided on the surface (lower surface 608) facing the light-sending pins 26. In the optical element 4, the refractive element 6 can adjust the angle of incidence of light A1 emitted from the light-sending pins 26 onto the optical bench 5. This allows the angle of incidence of light A1 onto the light-sending mirror 551 to be appropriately adjusted, reducing the loss of light A1 in the second waveguide 53 and improving the transmission efficiency of light A1.

[0192] The optical member 4 is used together with the optical chip 1 that receives the light A2. The optical member 4 includes an optical bench 5 and a refractive member 6. The optical bench 5 has a mirror 55 (a receiving-side mirror 552) and is disposed above the receiving-side optical pins 34 of the optical chip 1. The refractive member 6 is disposed between the optical bench 5 and the receiving-side optical pins 34. The refractive member 6 has a recess 60 (a second recess 62) provided on a surface (a lower surface 608) facing the receiving-side optical pins 34. In the optical member 4, the refractive member 6 can adjust the angle of incidence of the light A2 from the receiving-side mirror 552 onto the receiving-side optical pins 34. This reduces the loss of the light A2 at the receiving-side optical pins 34 and improves the transmission efficiency of the light A2.

[0193] (1.5) Summary of the Optical Module The optical module 100 includes a substrate 10, a light source 21, a first waveguide 24, a transmitting-side vertical waveguide (transmitting-side optical pin) 26, an optical bench 5, and a refractive member 6. The light source 21 is disposed on the upper surface 110 of the substrate 10. The first waveguide 24 has a diffractive member 25 and is disposed on the upper surface 110 of the substrate 10. The transmitting-side optical pin 26 is disposed above the diffractive member 25 and at an angle with respect to the upper surface 110 of the substrate 10. The optical bench 5 has a second waveguide (transmitting-side bench waveguide) 53 and a mirror 55 (transmitting-side mirror 551). The optical bench 5 is disposed above the transmitting-side optical pin 26. The refractive member 6 is disposed between the optical bench 5 and the transmitting-side optical pin 26. The refractive member 6 has a recess 60 (first recess 61 ) provided on the surface (lower surface 608 ) facing the light-sending side optical pin 26 .

[0194] In this optical module 100, light A1 emitted from light source 21 passes through first waveguide 24, light-sending vertical waveguide (light-sending optical pin) 26, refractive member 6, and light-sending mirror 551, in that order. In optical module 100, refractive member 6 can adjust the angle of incidence of light A1, emitted from light-sending pin 26 tilted with respect to top surface 110 of substrate 10, onto optical bench 5. This makes it possible to appropriately adjust the angle of incidence of light A1 onto light-sending mirror 551, reduce loss of light A1 in second waveguide 53, and improve the transmission efficiency of light A1.

[0195] According to an optical simulation performed by the inventors of the present application, the angle β of the light-sending side optical pin 26 ｐ When the inclination angle γ of the light-sending side mirror 551 is 8° and the inclination angle γ of the light-sending side mirror 551 is 45°, it was confirmed that by placing the refractive member 6 between the light-sending side optical pin 26 and the optical bench 5, the optical coupling loss is improved by about 5 dB compared to when the refractive member 6 is not present.

[0196] The optical module 100 also includes a substrate 10, a light-receiving component 31, a light-receiving vertical waveguide (light-receiving optical pin) 34, an optical bench 5, and a refractive member 6. The light-receiving component 31 is disposed on the upper surface 110 of the substrate 10. The light-receiving optical pin 34 is disposed above the light-receiving component 31 at an angle with respect to the upper surface 110 of the substrate 10. The optical bench 5 has a waveguide (light-receiving bench waveguide) 54 and a mirror 55 (light-receiving mirror 552). The optical bench 5 is disposed above the light-receiving optical pin 34. The refractive member 6 is disposed between the optical bench 5 and the light-receiving optical pin 34. The refractive member 6 has a recess 60 (second recess 62) provided on a surface (lower surface 608) facing the light-receiving optical pin 34.

[0197] In this optical module 100, the light-receiving component 31 receives light A2 that has passed through the light-receiving side mirror 552, the refractive member 6, and the light-receiving side vertical waveguide (light-receiving side optical pin) 34, in that order. In the optical module 100, the refractive member 6 can adjust the angle of incidence of light A2 from the light-receiving side mirror 552 onto the light-receiving side optical pin 34, which is inclined with respect to the top surface 110 of the substrate 10. This reduces the loss of light A2 in the light-receiving side optical pin 34, making it possible to improve the transmission efficiency of light A2.

[0198] According to an optical simulation performed by the inventors of the present application, the angle β of the light-receiving side optical pin 34 ｐ When the inclination angle γ of the light-receiving side mirror 552 is 8° and the inclination angle γ of the light-receiving side mirror 552 is 45°, it was confirmed that by placing the refractive member 6 between the light-receiving side optical pin 34 and the optical bench 5, the optical coupling loss is improved by about 2.5 dB compared to when the refractive member 6 is not present.

[0199] (2) Modifications The above embodiment is merely one of various embodiments of the present disclosure. The above embodiment can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Modifications of the embodiment are listed below. The above embodiment and the modifications described below can be applied in appropriate combinations. In the following description of each modification, the description of the same configuration as the above embodiment may be omitted as appropriate.

[0200] (2.1) Modification 1 An optical module 100 according to this modification will be described with reference to FIGS.

[0201] As shown in Figures 11 and 12, in the optical module 100 of this modified example, the first surface 611 of the first recess 61 of the refractive member 6 is an inclined surface inclined at an inclination angle α (see Figures 11 and 12) with respect to the lower surface 608 of the refractive member 6 so that the normal direction faces diagonally downward and rearward.

[0202] 11 and 12, conditions for propagating the light A1 within the second waveguide 53 along the extension direction of the second waveguide 53 (parallel to the extension direction) in the optical module 100 of this modified example will be described. In this modified example, the description will also focus on the −1st-order light A11.

[0203] In this modified example, when light A11 propagates from the refraction section 602 to the main body section 601, it may be refracted forward with respect to the normal to the upper surface 110 of the substrate 10 as shown in FIG. 11 (hereinafter also referred to as the "third case"), or it may be refracted backward with respect to the normal to the upper surface 110 of the substrate 10 as shown in FIG. 12 (hereinafter also referred to as the "fourth case").

[0204] In the third case (θ ｏ <α, see FIG. 11), equations (14) to (18) and equation (22) hold true from Snell's law, as in the first embodiment.

[0205] Furthermore, due to the relationship between angles, the following equations (36) and (37) hold true.

[0206]

[0207] Furthermore, the condition for reflecting the light A11 by the light-sending side mirror 551 along (parallel to) the extending direction of the second waveguide 53 is expressed by the following equation (38).

[0208]

[0209] The following equation (39) is obtained from equations (16) and (36), the following equation (40) is obtained from equations (17) and (37), and the following equation (41) is obtained from equations (18) and (38).

[0210]

[0211] When the formulas (22) and (39) to (41) are transformed with respect to γ, the following formula (42) is obtained.

[0212]

[0213] In addition, the third case is the condition θ ｏ <α is expressed by the following equation (42).

[0214]

[0215] In the fourth case (θ ｏ ≧α, see FIG. 12), equations (14) to (18) and equation (22) hold true from Snell's law, similarly to the third case.

[0216] Furthermore, due to the relationship between angles, the following equations (43) and (44) hold true.

[0217]

[0218] The condition for reflecting the light A11 by the light-sending side mirror 551 along (parallel to) the extending direction of the second waveguide 53 is expressed by the following equation (45).

[0219]

[0220] The following equation (46) is obtained from equations (16) and (43), the following equation (47) is obtained from equations (17) and (44), and the following equation (48) is obtained from equations (18) and (45).

[0221]

[0222] When the formulas (22) and (46) to (48) are transformed with respect to γ, the following formula (49) is obtained.

[0223]

[0224] In addition, the fourth case is the condition θ ｏ ≧α is expressed by the following equation (50).

[0225]

[0226] By designing the material and inclination angle α of the refractive member 6 (main body portion 601 and refractive portion 602) so that the above equations (41) and (42) are satisfied, or so that the above equations (49) and (50) are satisfied, a refractive member 6 having the desired first recess 61 can be obtained.

[0227] The refractive member 6 of this modified example further has a second recess 62. Note that a description of the second recess 62 will be omitted.

[0228] The optical module 100 of this modified example can also improve the optical transmission performance, similar to the optical module 100 of the embodiment.

[0229] (2.2) Modification 2 An optical module 100 of this modification will be described with reference to Fig. 13. In the optical module 100 of this modification, the configuration of the refractive member 6 is different from that of the optical module 100 of the embodiment.

[0230] As shown in FIG. 13 , in the optical module 100 of this modified example, the refractive member 6 includes a plurality of recesses 60 each having a first recess 61 and a second recess 62. Each recess 60 is a groove extending in the left-right direction. In each recess 60, the first recess 61 includes a first surface 611 inclined with respect to the upper surface 110 of the substrate 10 (the bottom surface 111 of the recess 102) and a second surface 612. In each recess 60, the second recess 62 includes a first surface 621 inclined with respect to the upper surface 110 of the substrate 10 (the bottom surface 111 of the recess 102) and a second surface 622. The plurality of recesses 60 have the same shape and extend in the left-right direction so as to be parallel to each other. In the refractive member 6, the plurality of recesses 60 form a repeated uneven structure 600. The repeated structure 600 may be a diffraction grating structure.

[0231] In the optical module 100 of this modified example, similarly to the optical module 100 of the embodiment, the transmission performance of the light A1 can be improved by refracting the light A1 with the refractive member 6 and adjusting the angle of incidence on the light-sending-side mirror 551. Also, the transmission performance of the light A2 can be improved by refracting the light A2 with the refractive member 6 and adjusting the angle of incidence on the light-receiving-side optical pin 34.

[0232] Furthermore, in the optical module 100 of this modified example, even if the refractive member 6 is positioned relatively forward or backward from the light-sending pins 26, the light A1 emitted from the light-sending pins 26 can be received by any of the plurality of first recesses 61. Moreover, even if the refractive member 6 is positioned relatively forward or backward from the light-receiving mirror 552, the light A2 emitted from the waveguide 54 can be received by any of the plurality of second recesses 62. In short, this configuration has the advantage that the light A1 and A2 from the light-sending pins 26 and the waveguide 54 are less likely to escape.

[0233] (2.3) Modification 3 An optical module 100 of this modification will be described with reference to Fig. 14. In the optical module 100 of this modification, the configuration of the refractive member 6 is different from that of the optical module 100 of the embodiment.

[0234] 14 , in the refractive member 6 of this modified example, the first recess 61 (recess 60) is provided on the upper surface 609 (surface facing the light-sending side mirror 551) of the refractive member 6. Although not shown, the second recess 62 (recess 60) is provided on the upper surface 609 (surface facing the light-receiving side mirror 552) of the refractive member 6.

[0235] In this modification as well, by appropriately designing the material of the refractive member 6 (main body portion 601 and refractive portion 602) and the inclination angle α of the first recess 61, it is possible to provide a refractive member 6 that can propagate light A1 after reflection by the light-sending side mirror 551 along the extension direction of the second waveguide 53. Furthermore, by appropriately designing the material of the refractive member 6 (main body portion 601 and refractive portion 602) and the inclination angle α of the second recess 62, it is possible to provide a refractive member 6 that can propagate light A2 along the extension direction of the light-receiving side optical pin 34. In short, in this modification as well, it is possible to improve the transmission performance of light A1 and A2.

[0236] (2.4) Modification 4 An optical module 100 of this modification will be described with reference to Fig. 15. In the optical module 100 of this modification, the configuration of the light-receiving side optical pins 34 is different from that of the optical module 100 of the embodiment.

[0237] 15 , in the optical chip 1 of this modified example, the light-receiving side vertical waveguide (light-receiving side optical pin) 34 is tapered from top to bottom. The phrase "the light-receiving side optical pin 34 is tapered" means that the optical pin core (light-receiving side vertical waveguide core) 348 is tapered.

[0238] In the optical module 100 of this modified example, the light-receiving side optical pins 34 are tapered downward, which has the advantage that the light A2 refracted by the refractive member 6 and incident on the light-receiving side optical pins 34 can be easily focused onto the light-receiving component 31 located below the light-receiving side optical pins 34. This is particularly useful when the size of the light-receiving component 31 is small.

[0239] The light-sending vertical waveguide (light-sending optical pin) 26 may also have a shape that tapers downward.

[0240] (2.5) Modification 5 The optical module 100 of this modification will be described with reference to FIG.

[0241] 16 , in the optical module 100 of this modified example, the width of the receiving-side vertical waveguide (receiving-side optical pin) 34 in the front-rear direction is larger than the width of the first surface 621 of the second recess 62 of the refractive member 6 in the front-rear direction. The "front-rear width of the receiving-side optical pin 34" refers to the dimension of the receiving-side optical pin 34 along a direction perpendicular to the up-down direction (front-rear direction) in a cross section including the normal direction (downward diagonal front) and the up-down direction of the receiving-side mirror 552. The "front-rear width of the first surface 621 of the second recess 62 of the refractive member 6" refers to the dimension of the first surface 621 along a direction perpendicular to the up-down direction (front-rear direction) in a cross section including the normal direction (downward diagonal front) and the up-down direction of the sending-side mirror 551. The "width of the receiving-side optical pin 34" refers to the width of the top surface of the optical pin core 348. When the upper surface of the optical pin core 348 is circular or the like, the "width of the light-receiving side optical pin 34" means the maximum width of the upper surface of the optical pin core 348. This makes it difficult for the light A2 that has passed through the second recess 62 to deviate from the light-receiving side optical pin 34. In short, this configuration has the advantage that it is difficult for the light A2 refracted by the second recess 62 of the refractive member 6 to escape.

[0242] 16 , in the optical module 100 of this modified example, the width in the front-to-rear direction of the light-receiving side vertical waveguide (light-receiving side optical pin) 34 is larger than the width in the front-to-rear direction of the light-receiving side mirror 552. Note that the "width in the front-to-rear direction of the light-receiving side mirror 552" refers to the dimension of the light-receiving side mirror 552 along a direction (front-to-rear direction) perpendicular to the up-to-down direction in a cross section including the normal direction (diagonally downward front) and the up-to-down direction of the light-receiving side mirror 552. This makes it less likely that light A2 reflected by the light-receiving side mirror 552 will deviate from the light-receiving side optical pin 34. In short, this configuration has the advantage that light A2 reflected by the light-receiving side mirror 552 is less likely to escape.

[0243] (2.6) Other Modifications In one modification, the optical member 4 may be used in combination with a device other than the optical chip 1 described in the embodiment. An example of such a device is a device in which the sending-side waveguide 23 does not include the first waveguide 24, the light source 21 is disposed below the sending-side optical pins 26, and light A1 is emitted obliquely from below the sending-side optical pins 26. Another example of such a device is a device in which the receiving-side waveguide 33 includes a diffractive member disposed below the receiving-side optical pins 34 and an additional waveguide extending in the direction of diffraction of light by the diffractive member, and the light-receiving component 31 is disposed at the output end of the light from the additional waveguide.

[0244] In one modified example, the cross-sectional shape of the recess 60 of the refractive member 6 is not limited to a triangle, and may be a polygon with four or more sides, a sector shape, etc. The first surface 611 (or 612) may be a bottom surface or a side surface of the first recess 61 (or the second recess 62). It is preferable that the first recess 61 (second recess 62) includes a first surface 611 (621) that is inclined with respect to the upper surface 110 of the substrate 10.

[0245] In one modification, the material of the bench substrate 51 is not limited to silicon, but may be an appropriate resin, metal, or the like.

[0246] In one modification, the optical chip 1 may have only one of the light transmitting and receiving configurations, rather than both, and in this case, the refractive member 6 may have only one of the first recess 61 and the second recess 62.

[0247] In one modified example, the light-sending side optical pins 26 and the light-receiving side optical pins 34 of the optical chip 1 do not have to be aligned in the left-right direction. In this case, the first recess 61 and the second recess 62 of the refractive member 6 do not have to be connected.

[0248] (3) Aspects As is clear from the above-described embodiments and modifications, the present specification discloses the following aspects.

[0249] The optical module (100) of the first aspect includes a substrate (10), a light source (21), a first waveguide (24), a vertical waveguide (transmitting-side optical pins 26), an optical bench (5), and a refractive member (6). The light source (21) is disposed on the upper surface (110) of the substrate (10). The first waveguide (24) has a diffractive member (25) and is disposed on the upper surface (110) of the substrate (10). The vertical waveguide (transmitting-side optical pins 26) is disposed above the diffractive member (25) and at an angle with respect to the upper surface (110) of the substrate (10). The optical bench (5) has a second waveguide (53) and a mirror (transmitting-side mirror 551) and is disposed above the vertical waveguide (transmitting-side optical pins 26). The refractive member (6) is disposed between the optical bench (5) and the vertical waveguide. The refractive member (6) has a recess (first recess 61) provided on the surface (lower surface 608) facing the vertical waveguide or the surface (upper surface 609) facing the mirror.

[0250] According to this aspect, the refractive element (6) makes it possible to appropriately adjust the angle of incidence of the light (A1) on the mirror (light-sending side mirror 551), thereby improving the transmission efficiency of the light (A1).

[0251] In the optical module (100) of the second aspect, the inner surface of the recess (first recess 61) of the refractive member (6) in the first aspect includes a first surface (611) below the mirror (light-transmitting side mirror 551). The first surface (611) is inclined with respect to the upper surface (110) of the substrate (10).

[0252] According to this aspect, light incident on the refractive member (6) from the vertical waveguide (light-sending side optical pin 26) can be refracted at the (A1) first surface (611) and incident on the second waveguide (53) at a desired angle.

[0253] In the optical module (100) of the third aspect, in the second aspect, the inner surface of the recess (first recess 61) of the refractive member (6) further includes a second surface (612) below the mirror (light-transmitting side mirror 551). In a cross-sectional view, the recess is surrounded by the first surface (611) and the second surface (612).

[0254] According to this aspect, the light (A1) incident on the refractive member (6) from the vertical waveguide (light-sending side optical pin 26) can be refracted at the first surface (611) and incident on the second waveguide (53) at a desired angle.

[0255] In the optical module (100) of the fourth aspect, in the second or third aspect, the front-to-rear dimension of the first surface (611) of the refractive member (6) is larger than the front-to-rear dimension of the vertical waveguide (light-sending side optical pin 26).

[0256] This embodiment has the advantage that the light (A1) emitted from the vertical waveguide (light-sending side optical pin 26) is less likely to deviate from the recess (first recess 61), making it less likely for the light (A1) to escape from the vertical waveguide.

[0257] In the optical module (100) of the fifth aspect, in any one of the first to fourth aspects, the light (A1) emitted from the light source (21) passes through the first waveguide (24), the vertical waveguide (light-sending side optical pin 26), the refractive member (6), and the mirror (light-sending side mirror 551) in that order.

[0258] According to this aspect, it is possible to improve the transmission efficiency of the light (A1).

[0259] In the optical module (100) of the sixth aspect, part of the light (A1) is reflected by the mirror (light-sending side mirror 551) and then reflected by the refractive member (6) in the fifth aspect.

[0260] According to this aspect, a part of the leaked light can be reflected by the refractive member (6), and the transmission efficiency of the light (A1) can be improved.

[0261] In the optical module (100) of the seventh aspect, in any one of the first to sixth aspects, the dimension of the mirror in the front-to-rear direction is larger than the dimension of the vertical waveguide (light-sending side optical pin 26) in the front-to-rear direction.

[0262] This embodiment has the advantage that the light (A1) emitted from the vertical waveguide (light-sending side optical pin 26) is less likely to deviate from the mirror (light-sending side mirror 551), making it less likely for the light (A1) to escape from the vertical waveguide.

[0263] The optical module (100) of the eighth aspect includes a substrate (10), a light-receiving component (31), a vertical waveguide (light-receiving-side optical pin 34), an optical bench (5), and a refractive member (6). The light-receiving component (31) is disposed on the upper surface (110) of the substrate (10). The vertical waveguide is disposed above the light-receiving component (31) and at an angle with respect to the upper surface (110) of the substrate (10). The optical bench (5) has a waveguide (54) and a mirror (light-receiving-side mirror 552), and is disposed above the vertical waveguide. The refractive member (6) is disposed between the optical bench (5) and the vertical waveguide. The refractive member (6) has a recess (second recess 62) provided on a surface (lower surface 608) facing the vertical waveguide or a surface (upper surface 609) facing the mirror.

[0264] According to this aspect, the refractive member (6) makes it possible to appropriately adjust the angle of incidence on the vertical waveguide (light-receiving side optical pin 34), thereby improving the transmission efficiency of the light (A2).

[0265] In the optical module (100) of the ninth aspect, the inner surface of the recess (second recess 62) of the refractive member (6) in the eighth aspect includes a first surface (621) below the mirror (light-receiving side mirror 552). The first surface (621) is inclined with respect to the upper surface (110) of the substrate (10).

[0266] According to this aspect, the light (A2) incident on the refractive member (6) from the waveguide (54) can be refracted at the first surface (621) and incident on the vertical waveguide (receiving side optical pin 34) at a desired angle.

[0267] In the optical module (100) of the tenth aspect, in the ninth aspect, the inner surface of the recess (second recess 62) of the refractive member (6) further includes a second surface (622) below the mirror (light-receiving side mirror 552). In a cross-sectional view, the recess is surrounded by the first surface (621) and the second surface (622).

[0268] According to this aspect, the light (A2) incident on the refractive member (6) from the waveguide (54) can be refracted at the first surface (621) and incident on the vertical waveguide (receiving side optical pin 34) at a desired angle.

[0269] In the optical module (100) of the eleventh aspect, in the ninth or tenth aspect, the front-to-rear dimension of the vertical waveguide (receiving side optical pin 34) is larger than the front-to-rear dimension of the first surface (621) of the refractive member (6).

[0270] According to this aspect, there is an advantage that the light (A2) that has passed through the recess (second recess 62) is less likely to deviate from the vertical waveguide (light-receiving side optical pin 34), and the light (A2) refracted in the recess of the refractive member (6) is less likely to escape.

[0271] In the optical module (100) of the twelfth aspect, in any one of the eighth to eleventh aspects, the light receiving component (31) receives light (A2) that has passed through the mirror (light receiving side mirror 552), the refractive member (6), and the vertical waveguide (light receiving side optical pin 34) in that order.

[0272] According to this aspect, it is possible to improve the transmission efficiency of the light (A2).

[0273] In the optical module (100) of the thirteenth aspect, in the twelfth aspect, the vertical waveguide (light-receiving-side optical pin 34) is tapered downward.

[0274] This embodiment has the advantage that the light (A2) incident on the vertical waveguide (light-receiving side optical pin 34) can be easily focused onto the light-receiving component (31) located below the vertical waveguide.

[0275] In the optical module (100) of the fourteenth aspect, in any one of the first to thirteenth aspects, the dimension in the front-to-rear direction of the vertical waveguide (light-receiving side optical pin 34) is larger than the dimension in the front-to-rear direction of the mirror.

[0276] According to this aspect, there is an advantage that the light (A2) reflected by the mirror (light-receiving side mirror 552) is less likely to deviate from the vertical waveguide (light-receiving side optical pin 34), and the light (A2) reflected by the mirror is less likely to escape.

[0277] In the optical module (100) of the fifteenth aspect, in any one of the first to fourteenth aspects, the inclination angle (β ｑ１) is larger than the inclination angle (γ) of the mirrors (light-sending side mirror 551, light-receiving side mirror 552) with respect to the substrate (10).

[0278] According to this aspect, it is possible to reduce the loss of the light (A1, A2) when it passes through the refractive member (6).

[0279] In the optical module (100) of the sixteenth aspect, in any one of the first to fifteenth aspects, the refractive member (6) has a main body portion (601) provided with recesses (first recess 61, second recess 62) and a refractive portion (602) located inside the recesses. The main body portion (601) and the refractive portion (602) have different refractive indices.

[0280] According to this aspect, it is possible to improve the transmission efficiency of the light (A1, A2).

[0281] The optical module (100) of the seventeenth aspect is the optical module of any one of the first to sixteenth aspects, further comprising an optical fiber (91) optically coupled to the optical bench (5).

[0282] According to this aspect, it is possible to improve the transmission efficiency of the light (A1, A2) between the optical fiber (91) and the vertical waveguide (light-sending side optical pin 26, light-receiving side optical pin 34).

[0283] An optical element (4) of an eighteenth aspect is used together with an optical chip (1) that emits light (A1). The optical element (4) includes an optical bench (5) and a refractive element (6). The optical bench (5) has a mirror (light-sending mirror 551) and is disposed above a vertical waveguide (light-sending pin 26) of the optical chip (1). The refractive element (6) is disposed between the optical bench (5) and the vertical waveguide. The refractive element (6) has a recess (first recess 61) provided on a surface (lower surface 608) facing the vertical waveguide or a surface (upper surface 609) facing the mirror.

[0284] According to this aspect, it is possible to improve the transmission efficiency of the light (A1).

[0285] The optical member (4) of the nineteenth aspect is used together with an optical chip (1) that receives light (A2). The optical member (4) includes an optical bench (5) and a refractive member (6). The optical bench (5) has a mirror (receiving-side mirror 552) and is disposed above the vertical waveguide (receiving-side optical pin 34) of the optical chip (1). The refractive member (6) is disposed between the optical bench (5) and the vertical waveguide. The refractive member (6) has a recess (second recess 62) provided on a surface (lower surface 608) facing the vertical waveguide or a surface (upper surface 609) facing the mirror.

[0286] According to this aspect, it is possible to improve the transmission efficiency of the light (A2).

[0287] 100 Optical module 1 Optical chip 10 Substrate 21 Light source 24 First waveguide 25 Diffraction member 26 Light-transmitting side optical pin (light-transmitting side vertical waveguide) 5 Optical bench 31 Light-receiving component 34 Light-receiving side optical pin (light-receiving side vertical waveguide) 4 Optical member 53 Light-transmitting side bench waveguide (second waveguide) 54 Light-receiving side bench waveguide (waveguide) 55 Mirror 551 Light-transmitting side mirror 552 Light-receiving side mirror 6 Refraction member 601 Main body 602 Refraction portion 60 Recess 61 First recess 611 First surface 612 Second surface 62 Second recess 621 First surface 622 Second surface 91 Optical fiber A1 Light A2 Light β ｑ１ Tilt angle γ Tilt angle

Claims

1. An optical module comprising: a substrate; a light source disposed on an upper surface of the substrate; a first waveguide having a diffractive member and disposed on the upper surface of the substrate; a vertical waveguide disposed above the diffractive member and tilted with respect to the upper surface of the substrate; an optical bench having a second waveguide and a mirror and disposed above the vertical waveguide; and a refractive member disposed between the optical bench and the vertical waveguide, wherein the refractive member has a recess provided on a surface facing the vertical waveguide or a surface facing the mirror.

2. The optical module according to claim 1, wherein the inner surface of the recess of the refractive member includes a first surface below the mirror, and the first surface is inclined with respect to the upper surface of the substrate.

3. An optical module according to claim 2, wherein the inner surface of the recess of the refractive member further includes a second surface located below the mirror, and the recess is surrounded by the first surface and the second surface in a cross-sectional view.

4. An optical module according to claim 2 or 3, wherein the width of the first surface of the refractive member in the front-to-rear direction is greater than the width of the vertical waveguide in the front-to-rear direction.

5. An optical module according to any one of claims 1 to 4, wherein light emitted from the light source passes through the first waveguide, the vertical waveguide, the refractive member, and the mirror in that order.

6. The optical module according to claim 5, wherein a portion of the light is reflected by the refractive member after being reflected by the mirror.

7. An optical module according to any one of claims 1 to 6, wherein the width of the mirror in the front-to-rear direction is greater than the width of the vertical waveguide in the front-to-rear direction.

8. An optical module comprising: a substrate; a light-receiving component arranged on an upper surface of the substrate; a vertical waveguide arranged above the light-receiving component and inclined with respect to the upper surface of the substrate; an optical bench having a waveguide and a mirror and arranged above the vertical waveguide; and a refractive member arranged between the optical bench and the vertical waveguide, wherein the refractive member has a recess provided on a surface facing the vertical waveguide or a surface facing the mirror.

9. The optical module according to claim 8, wherein the inner surface of the recess of the refractive member includes a first surface below the mirror, the first surface being inclined with respect to the upper surface of the substrate.

10. An optical module according to claim 9, wherein the inner surface of the recess of the refractive member further includes a second surface located below the mirror, and the recess is surrounded by the first surface and the second surface in a cross-sectional view.

11. An optical module according to claim 9 or 10, wherein the width of the vertical waveguide in the front-to-rear direction is greater than the width of the first surface of the refractive member in the front-to-rear direction.

12. An optical module according to any one of claims 8 to 11, wherein the light receiving component receives light that has passed through the mirror, the refractive member, and the vertical waveguide in that order.

13. The optical module according to claim 12, wherein the vertical waveguide tapers downward.

14. An optical module according to any one of claims 8 to 13, wherein the width of the vertical waveguide in the front-to-rear direction is greater than the width of the mirror in the front-to-rear direction.

15. An optical module according to any one of claims 1 to 14, wherein the vertical waveguide has an inclination angle relative to the substrate that is larger than the inclination angle of the mirror relative to the substrate.

16. An optical module according to any one of claims 1 to 15, wherein the refractive member has a main body portion in which the recess is provided and a refractive portion located inside the recess, and the main body portion and the refractive portion have different refractive indices.

17. The optical module according to any one of claims 1 to 16, further comprising an optical fiber optically coupled to the optical bench.

18. An optical element used together with an optical chip that emits light, or an optical element used together with an optical chip that receives light, comprising: an optical bench having a mirror and arranged above a vertical waveguide of the optical chip; and a refractive element arranged between the optical bench and the vertical waveguide, wherein the refractive element has a recess provided on a surface facing the vertical waveguide or a surface facing the mirror.

Images