Optical system and optical connector

Abstract

This optical system (1) comprises: a reflective surface (30); a plurality of first lenses (21) that are disposed between a second plane (P2) and the reflective surface (30) and that each form a first focal point (F1) on a first plane (P1) side via the reflective surface (30); and a plurality of second lenses (22) that are disposed between the second plane (P2) and the plurality of first lenses (21), that each form a plurality of second focal points (F2) on a second plane (P2) side, and that form one-to-one pairs with the plurality of first lenses (21). The end surfaces of a plurality of cores (51) are respectively positioned at the plurality of second focal points (F2), and a plurality of light-emitting elements (41) are respectively positioned at the plurality of first focal points (F1). Light (L1) (optical signal) is transmitted via an optical path formed between a first lens (21) and a second lens (22) that form a pair.

Description

Optical System and Optical Connector

[0006] ,

[0005] ,

[0001] The present invention relates to an optical system for transmitting light between an optical fiber and a light-emitting element or a light-receiving element, and an optical connector using the same.

[0002] Conventionally, optical transmission systems that transmit optical signals through optical fibers have been used in various communication systems. For example, in a data center where a large number of servers are installed, adjacent servers are connected by optical fibers for data transfer. By using multiple cores for the transmission of optical signals, it is possible to increase the speed and capacity of data transmission. Such a multi-core configuration can be realized by using a multi-core optical fiber in which multiple cores are arranged in one optical fiber, or by bundling multiple single-core optical fibers.

[0003] In such an optical transmission system, an optical connector is used to convert an electrical signal into an optical signal and incident it on the optical fiber, or to receive the optical signal emitted from the optical fiber and convert it into an electrical signal. In the optical connector described in Patent Document 1, the optical signal emitted from the optical fiber is reflected by the first lens and collimated by the second lens disposed below the first lens. Thereafter, the optical signal is converted into an electrical signal by a photoelectric conversion element disposed below the second lens. ​​​​​​​Furthermore, when optical connectors are installed on a server as described above, the light-emitting or light-receiving elements of the optical connector are connected to the server-side circuitry (e.g., the CPU) by wiring. In this case, the longer the wiring, the more susceptible the electrical signal is to noise, and the greater the loss of electrical signals. This problem becomes more pronounced as the transmission frequency of the electrical signal is increased to improve data transmission efficiency. For this reason, it is preferable that the wiring connecting the light-emitting or light-receiving elements of the optical connector to the server-side circuitry (e.g., the CPU) be as short as possible. Therefore, if the optical signal transmission path within the optical connector can be made longer and part of the wiring can be supplemented by this transmission path, the wiring can be shortened accordingly, and the loss of electrical signals can be suppressed.

[0007] In view of these challenges, the present invention aims to provide an optical system and an optical connector that can achieve a low profile while extending the optical signal transmission path.

[0008] A first aspect of the present invention relates to an optical system for transmitting optical signals. The optical system according to this aspect includes: a reflective surface arranged at a predetermined angle with respect to a first plane and a second plane that are substantially orthogonal to each other; a plurality of first lenses arranged between the second plane and the reflective surface, each forming a first focal point on the first plane side via the reflective surface; and a plurality of second lenses arranged between the second plane and the plurality of first lenses, each forming a plurality of second focal points on the second plane side, and paired one-to-one with the plurality of first lenses. The end faces of a plurality of cores for optical transmission are positioned at the plurality of second focal points, and a plurality of light-emitting elements or a plurality of photodetectors are positioned at the plurality of first focal points. An optical path for transmitting the optical signal is formed between the pair of first lenses and second lenses, and the optical signal is transmitted between the core and the light-emitting element or photodetector corresponding to each optical path.

[0009] In the optical system according to this embodiment, both the multiple first lenses and the multiple second lenses are arranged between the second plane and the reflective surface, and these lenses are within the height range of the reflective surface, so the height of the optical system can be effectively suppressed. Furthermore, since the light passing through the optical paths formed between the multiple first lenses and the multiple second lenses is substantially parallel light, the optical signal can be transmitted well even if the distance between the multiple first lenses and the multiple second lenses is extended to lengthen these optical paths. Therefore, the optical signal transmission path between the reflective surface and the end faces of the multiple cores, including this optical path, can be lengthened. Thus, in the optical system according to this embodiment, the optical signal transmission path in the optical system can be lengthened while achieving a low profile for the optical system.

[0010] A second aspect of the present invention relates to an optical connector. The optical connector according to this aspect comprises an optical system according to the first aspect, at least one optical fiber constituting the plurality of cores, the plurality of light-emitting elements or the plurality of light-receiving elements, and a support member that supports the optical system, the optical fiber, and the plurality of light-emitting elements or the plurality of light-receiving elements.

[0011] According to the optical connector of this embodiment, since the optical system of the first embodiment is used, the same effects as in the first embodiment can be achieved.

[0012] As described above, the present invention provides an optical system and optical connector that can achieve a low profile while extending the optical signal transmission path.

[0013] The effects and significance of the present invention will become even clearer from the description of the embodiments shown below. However, the embodiments shown below are merely examples of how to implement the present invention, and the present invention is not limited in any way to those described in the embodiments below.

[0014] Figure 1 is a diagram showing the configuration of the optical system according to Embodiment 1. Figure 2 is a perspective view showing the configuration of the support member according to Embodiment 1. Figure 3 is a plan view showing the configuration of the support member according to Embodiment 1. Figure 4 is a schematic perspective view showing the configuration of the light guide member according to Embodiment 1. Figure 5 is a perspective view showing the configuration of the optical connector according to Embodiment 1. Figure 6 is a schematic cross-sectional view showing the configuration of the optical connector according to Embodiment 1. Figures 7(a) and 7(b) are graphs showing the results of simulations obtained for the light intensity distribution at the incident end face of the core according to Embodiment 1, respectively. Figure 8 is a schematic cross-sectional view showing the configuration of the optical connector according to a modified example of Embodiment 1. Figure 9 is a schematic cross-sectional view showing the configuration of the optical connector according to Embodiment 2. Figure 10 is a schematic cross-sectional view showing the configuration of the optical connector according to Embodiment 3. Figure 11 is a graph showing the results of simulations obtained for the light intensity distribution at the incident end faces of the two lower cores out of four cores according to Embodiment 3. Figure 12 is a graph showing the results of a simulation of the light intensity distribution at the incident end faces of the two upper cores out of four cores according to Embodiment 3. Figures 13(a) to (c) are schematic diagrams showing various installation configurations for installing the light guide member on the support member according to Embodiment 4. Figures 14(a) to (c) are schematic diagrams showing various installation configurations for installing the light guide member on the support member according to Embodiment 4. Figures 15(a) and (b) are schematic side and plan views showing the configuration for installing the light guide member on the support member according to installation configuration 7 of Embodiment 4, respectively. Figures 16(a) and (b) are schematic side and plan views showing the configuration for installing the light guide member on the support member according to installation configuration 8 of Embodiment 4, respectively. Figures 17(a) and (b) are schematic side and plan views showing the configuration for installing the light guide member on the support member according to installation configuration 9 of Embodiment 4, respectively. Figures 18(a) and 18(b) are schematic side and plan views, respectively, showing the configuration for installing the light guide member on the support member according to the installation configuration 10 of Embodiment 4. Figures 19(a) and 19(b) are schematic side and plan views, respectively, showing the configuration for installing the light guide member on the support member according to the installation configuration 11 of Embodiment 4.Figure 20 is a schematic side view and a plan view showing the configuration for installing the light guide member on the support member according to the installation configuration 12 of Embodiment 4.

[0015] However, the drawings are for illustrative purposes only and do not limit the scope of this invention.

[0016] Embodiments of the present invention will be described below with reference to the figures. For convenience, each figure is labeled with mutually orthogonal X, Y, and Z axes. The positive Y-axis direction is the height direction of the optical system 1 and the optical connector 2, and the X-axis direction is the width direction of the optical system 1 and the optical connector 2.

[0017] <Embodiment 1> Figure 1 is a perspective view showing the configuration of the optical system 1 according to Embodiment 1. Figures 2 and 3 are a perspective view and a plan view, respectively, showing the configuration of the support member 10 according to Embodiment 1.

[0018] As shown in Figure 1, in Embodiment 1, three optical systems 1 are arranged in a line along the X-axis. Each optical system 1 comprises a support member 10, a light guide member 20, and a reflective surface 30. Here, one support member 10 common to the three optical systems 1 is used. The support member 10 is made of, for example, silicon. The outer shape of the support member 10 is formed by etching a cubic prototype of the support member 10.

[0019] As shown in Figures 2 and 3, the support member 10 has a rectangular shape that is elongated in the Z-axis direction when viewed from above. The lower surface of the support member 10 is a plane that is parallel to the X-Z plane over its entire length. The upper surface 11 of the support member 10 on the positive Z-axis side is higher than the upper surface 12 of the support member 10 on the negative Z-axis side. Multiple wirings 13, which will be connected to the substrate 40 (see Figure 5) described later, are arranged on the upper surface 11 by thin film formation. The multiple wirings 13 are divided into sections for each optical system 1 in Figure 1. The wirings 13 in each section have a similar layout to each other.

[0020] Three recesses 15 are formed at the Z-axis negative end of the upper surface 11. The three recesses 15 are all the same shape. The three recesses 15 are provided within the range of the three optical systems 1 in Figure 1. Each recess 15 is open on the Z-axis negative side. When viewed in the Z-axis positive direction, each recess 15 is rectangular in shape. That is, each recess 15 has a bottom surface 15a parallel to the X-Z plane and two inner surfaces facing each other in the X-axis direction and parallel to the Y-Z plane. The bottom surface 15a constitutes the mounting surface (first mounting surface) on which the light guide member 20 in Figure 1 is installed.

[0021] The inner surface of each recess 15 on the positive Z-axis side is an inclined surface tilted at 45° with respect to the X-Z plane in a direction parallel to the Y-Z plane. A reflective surface 30 is positioned on this inclined surface. Each reflective surface 30 is formed, for example, by depositing a highly reflective metallic material onto each inclined surface. If the inclined surface itself has high reflectivity, the inclined surface itself may be used as the reflective surface 30.

[0022] Three fiber support sections 14 are arranged on the upper surface 12 on the negative Z-axis side. The three fiber support sections 14 are provided within the range of the three optical systems 1 shown in Figure 1. Each fiber support section 14 has a valley shape of a certain depth that extends in the Z-axis direction. When viewed in the Z-axis direction, each valley shape is V-shaped. The deepest part of the valley shape extends parallel to the Z-axis, and two inclined surfaces are connected to this deepest part. The angle between each inclined surface and the X-Z plane is the same. This angle is set to, for example, 35°. This allows the valley shape of the fiber support section 14 to be formed accurately at a predetermined depth by etching, in relation to the crystal orientation of silicon.

[0023] Three light guide members 20 are fitted into the three recesses 15 in Figure 2, and these light guide members 20 are installed on the bottom surface 15a (first installation surface) of these recesses 15. This constitutes three optical systems 1 as shown in Figure 1. Each light guide member 20 is fixed to the support member 10 by applying adhesive to the boundary between each light guide member 20 and the recess 15.

[0024] Figure 4 is a schematic perspective view showing the configuration of the light guide member 20.

[0025] The light guide member 20 is made of a material with high light transmittance. The light guide member 20 has a rectangular parallelepiped shape that is long in the Z-axis direction. Four first lenses 21 are integrally arranged on the positive Z-axis side of the light guide member 20, and four second lenses 22 are integrally arranged on the negative Z-axis side of the light guide member 20. The four first lenses 21 and the four second lenses 22 are made of refractive lenses.

[0026] The four first lenses 21 are collimator lenses, and the four second lenses 22 are also collimator lenses. When viewed in the Z-axis direction, the positions of the four first lenses 21 and the positions of the four second lenses 22 overlap. In Embodiment 1, the optical axis of each first lens 21 is aligned with the optical axis of the second lenses 22 which are aligned in the Z-axis direction.

[0027] The four first lenses 21 and four second lenses 22 and the light guide member 20 are integrally formed, for example, by glass molding. In this case, the four first lenses 21, four second lenses 22 and the light guide member 20 are made of high-transmittance glass. However, the invention is not limited to this, and the four first lenses 21, four second lenses 22 and the light guide member 20 may be made of a transparent resin material. Alternatively, the four first lenses 21 and four second lenses 22 may not be integrally formed, but may be separately fixed to two sides of the light guide member 20 by transparent adhesive means. Alternatively, the four first lenses 21 and four second lenses 22 and the light guide member 20 may be integrally formed from light-transmitting silicon. In this case, the four first lenses 21 and four second lenses 22 are formed on the light guide member 20 by etching the silicon substrate.

[0028] Returning to Figure 1, with the light guide member 20 installed in the recess 15, the upper surface of the light guide member 20 and the upper surface 11 of the support member 10 are in the same plane. That is, with the light guide member 20 installed in the recess 15, the height of the upper surface of the light guide member 20 is the same as the height of the upper surface 11.

[0029] Figure 5 is a perspective view showing the configuration of the optical connector 2 according to Embodiment 1.

[0030] Three optical systems 1 are combined with three substrates 40 and three optical fibers 50 to form an optical connector 2. The three substrates 40 are placed on the upper surface 11 of the support member 10 and the upper surface of the light guide member 20 so as to cover the three reflective surfaces 30 in Figure 1.

[0031] At this time, each terminal located on the lower surface of the substrate 40 overlaps with the end of the corresponding wiring 13. Bumps (solder) 42 (see Figure 6) are placed between each terminal and the end of the corresponding wiring 13, thereby electrically and mechanically joining the terminal and the end of the corresponding wiring 13. Bumps (solder) 42 (see Figure 6) are also placed where the upper surface of the light guide member 20 and the substrate 40 overlap, thereby mechanically joining the substrate 40 and the light guide member 20. In this way, the three substrates 40 are installed on the upper surface 11 of the support member 10. The area of ​​the upper surface 11 where the substrates 40 overlap constitutes the installation surface (second installation surface) of the substrates 40.

[0032] The three optical fibers 50 are each installed in three fiber support portions 14 formed on the upper surface 12 of the support member 10 on the negative Z-axis side. Each optical fiber 50 is a multicore fiber having four cores 51 (see Figure 6). Each core 51 is a single-mode core. Therefore, each core 51 has high coupling efficiency with light having a Gaussian light intensity distribution.

[0033] Each optical fiber 50 is installed in the corresponding fiber support portion 14 such that the four cores 51 located on the Z-axis positive end face face the four second lenses 22 of the light guide member 20. At this time, an adhesive such as ultraviolet-curing resin is applied between each optical fiber 50 and the valley shape of the corresponding fiber support portion 14, thereby fixing each optical fiber 50 to the corresponding fiber support portion 14. In this way, the ends of the three optical fibers 50 are installed on the upper surface 12 of the support member 10. Although multi-core fibers are mentioned here, a configuration in which multiple single-core fibers are arranged may also be used.

[0034] In the optical connector 2 for transmitting an optical signal to the optical fiber 50, four light-emitting elements are arranged on the underside of the substrate 40. The optical signals emitted from these four light-emitting elements are incident on the four cores 51 of the optical fiber 50 via the reflective surface 30 and the light guide member 20. On the other hand, in the optical connector 2 for receiving an optical signal from the optical fiber 50, four light-receiving elements are arranged on the underside of the substrate 40. The optical signals emitted from the four cores 51 of the optical fiber 50 are received by the four light-receiving elements arranged on the underside of the substrate 40 via the light guide member 20 and the reflective surface 30.

[0035] Figure 6 is a schematic cross-sectional view showing the configuration of the optical connector 2.

[0036] Figure 6 shows a cross-sectional view of the optical connector 2 when it has only one optical system 1. Here, four light-emitting elements 41 are arranged on the substrate 40. The lower part of Figure 6 shows a cross-section of the optical connector 2 when it is cut by a plane that includes the center positions of the two light-emitting elements 41 on the positive X-axis side and is parallel to the Y-Z plane. When the optical connector 2 has multiple optical systems 1 as shown in Figure 5, the cross-sectional view of each part of the optical system 1 is the same as in Figure 6.

[0037] The top right figure in Figure 6 shows the configuration of the substrate 40, enclosed by the dashed-dotted line of the rectangle in the bottom right of Figure 6, when viewed in the positive Y-axis direction. The top left figure in Figure 6 shows the configuration of the optical fiber 50, enclosed by the dashed-dotted line of the rectangle in the bottom left of Figure 6, when viewed in the negative Z-axis direction. The second figure from the right in the top row of Figure 6 shows the configuration of the light guide member 20 (four first lenses 21), enclosed by the dashed-dotted line of the rectangle in the second figure from the right in the bottom row of Figure 6, when viewed in the negative Z-axis direction. The second figure from the left in the top row of Figure 6 shows the configuration of the light guide member 20 (four second lenses 22), enclosed by the dashed-dotted line of the rectangle in the second figure from the left in the bottom row of Figure 6, when viewed in the positive Z-axis direction.

[0038] The height of the upper surface of the light guide member 20 is the same as the height of the upper surface 11 of the support member 10. The substrate 40 is positioned to straddle the upper surface of the light guide member 20 and the upper surface 11 of the support member 10, and is joined to each upper surface by bumps 42. As described above, the inclination angle θ1 of the reflective surface 30 is 45°. That is, the reflective surface 30 is positioned at an inclination of only 45° with respect to the mutually orthogonal first plane P1 and second plane P2. The first plane P1 is parallel to the X-Z plane, and the second plane P2 is parallel to the X-Y plane. The first plane P1 and the second plane P2 only need to be substantially orthogonal. Also, the inclination angle θ1 only needs to be substantially 45°.

[0039] The four first lenses 21 are positioned between the second plane P2 and the reflective surface 30. Each of the four first lenses 21 has a first focal point F1 that is positioned at a different location on the first plane P1. That is, the optical axis of each first lens 21 is bent by 90° at the reflective surface 30 to reach the first plane P1. The length of the optical axis from each first lens 21 to the first plane P1 is equal to the focal length of each first lens 21. The focal lengths of these first lenses 21 are equal to each other. The substrate 40 is installed so that four light-emitting elements 41 are positioned at each of these four first focal points F1. The four first focal points F1 are positioned at the center of each of the four light-emitting elements 41.

[0040] The four second lenses 22 are positioned between the second plane P2 and the four first lenses 21. Each of the second focal points F2 of the four second lenses 22 is positioned at a different location on the second plane P2. That is, the length of the optical axis of each second lens 22 from each second lens 22 to the second plane P2 is equal to the focal length of each second lens 22. The focal lengths of these second lenses 22 are equal to each other. Optical fibers 50 are installed such that the end faces of multiple cores 51 for optical transmission are positioned at each of these four second focal points F2. The four second focal points F2 are positioned at the center of the end faces of the four cores 51.

[0041] The first lens 21 and the second lens 22 (the first lens 21 and the second lens 22 that form a pair) arranged in the Z-axis direction are aligned with each other's optical axes as described above. These optical axes are parallel to the Z-axis. The optical axes of the four second lenses 22 are respectively aligned with the optical axes of the four cores 51 at the end of the optical fiber 50. The focal lengths of the four first lenses 21 are equal to each other, and the focal lengths of the four first lenses 21 are also equal to each other. Also, the focal length of the first lens 21 and the focal length of the second lens 22 are equal to each other.

[0042] As an example, the mode field diameter (MFD) of the core 51 is about 6 to 8 μm. Also, as an example, the interval (center-to-center distance) between the cores 51 arranged in the X-axis direction is about 40 to 50 μm, and the interval (center-to-center distance) between the cores 51 arranged in the Y-axis direction is also about 40 to 50 μm. The four light-emitting elements 41, four first lenses 21, and four second lenses 22 are arranged with the same layout and interval (center-to-center distance) as the four cores 51.

[0043] Each light-emitting element 41 is composed of a surface-emitting laser such as a VCSEL. These light-emitting elements 41 are of the same type and have the same height (thickness). Each light-emitting element 41 emits light L1 (optical signal) in the negative Y-axis direction at a radiation angle of about NA 0.1 to 0.2. The wavelength of the light L1 is included in the range of 850 nm or more and 1550 nm or less. The light-emitting element "41" may be other light-emitting elements than the surface-emitting laser. This includes elements that emit light outside the chip from an IC chip provided with an Si photonics waveguide via a grating or a mirror. Each light-emitting element 41 is driven by its respective drive signal modulated according to the transmission data. These drive signals are input from the circuit unit to each light-emitting element 41 via the wiring 13.

[0044] The light L1 emitted from each light-emitting element 4' is reflected in the negative Z-axis direction by the reflecting surface <30> and enters the corresponding first lens 21. As described above, since each light-emitting element 4' is arranged at each first focal point F1, each light L1 is collimated by the corresponding first lens 21.

[0045] Thereafter, each light beam L1 propagates inside the light guide member 20 and enters the corresponding second lens 22. As described above, since the end faces of the respective cores 51 are arranged at the respective second foci F2, each light beam L1 is focused by the corresponding second lens 22 onto the end face of the corresponding core 51. The beam diameter of the light beam L1 at the end face of the core 51 is about the above-mentioned MFD.

[0046] Thus, an optical path for transmitting the light beam L1 (optical signal) is formed between the paired first lens 21 and second lens 22, and the light beam L1 (optical signal) is transmitted between the light emitting element

[41] corresponding to each optical path and the core 51. Here, since four transmission systems are used to simultaneously transmit different optical signals, the transmission capacity of the optical signals can be increased.

[0047] FIGS. 7(a) and 7(b) are graphs showing the results obtained by simulating the intensity distribution of the light beam L1 at the incident end face (second plane P2) of the core 51 in FIG. 6.

[0048] As described above, in the configuration of FIG. 6, the tilt angle θ1 is set to 45°, the optical axes of the paired first lens 21, second lens 22, and core 51 are aligned with each other, and the focal length of the first lens

[21] is equal to the focal length of the second lens 22. For this reason, as shown in FIGS. 7(a) and 7(b), the intensity distribution of the light beam L1 at the incident end face of the core [5]1 becomes a substantially similar Gaussian distribution over the entire circumference. Therefore, as described above, when the light beam L [1] is focused onto the incident end face of the single-mode core 5 [ [1]] with a beam diameter of about the MFD of the core 51, the optical coupling efficiency between the light beam L1 and the core 51 increases. For this reason, the optical loss when the light beam L1 enters the core 51 from the optical system [1] can be effectively suppressed.

[0049] As described above, according to the configuration of the first embodiment, it is possible to transmit a large-capacity optical signal through four transmission systems while suppressing the loss of the optical signal.

[0050] <Effects of the First Embodiment> According to the first embodiment, the following effects are obtained.

[0051] It should be noted that there are some unclear references in the original text (such as

[41] ,

[21] , [5]1, [1] in the translation), which may need to be further clarified according to the actual context.As shown in Figures 1 and 6, the optical system 1 includes a reflective surface 30 positioned at a predetermined inclination angle θ1 (45°) with respect to a first plane P1 and a second plane P2 that are substantially orthogonal to each other, a plurality of first lenses 21 positioned between the second plane P2 and the reflective surface 30 and each forming a first focal point F1 on the first plane P1 side via the reflective surface 30, and a plurality of second lenses 22 positioned between the second plane P2 and the plurality of first lenses 21 and each forming a plurality of second focal points F2 on the second plane P2 side, and paired one-to-one with the plurality of first lenses 21. The end faces of a plurality of cores 51 for optical transmission are positioned at the plurality of second focal points F2, and a plurality of light-emitting elements 41 are positioned at the plurality of first focal points F1, and an optical path for transmitting an optical signal is formed between the paired first lenses 21 and second lenses 22, and light L1 (optical signal) is transmitted between the core 51 and the light-emitting element 41 corresponding to each optical path.

[0052] With this configuration, both the multiple first lenses 21 and the multiple second lenses 22 are arranged between the second plane P2 and the reflective surface 30, and since these lenses are within the height range of the reflective surface 30, the height of the optical system 1 can be effectively suppressed. Furthermore, since the light L1 passing through the optical paths formed between the multiple first lenses 21 and the multiple second lenses 22 is substantially parallel light, the optical signal can be transmitted well even if the distance between the multiple first lenses 21 and the multiple second lenses 22 is extended to lengthen these optical paths. Therefore, the optical signal transmission path between the reflective surface 30 and the end faces of the multiple cores 51, including this optical path, can be lengthened. Thus, the optical system 1 according to Embodiment 1 makes it possible to lengthen the optical signal transmission path in the optical system 1 while achieving a low profile for the optical system 1.

[0053] As shown in Figure 6, multiple first focal points F1 are formed on the first plane P1, and multiple second focal points F2 are formed on the second plane P2.

[0054] With this configuration, since it is sufficient to arrange multiple light-emitting elements 41 on the first plane P1, if these light-emitting elements 41 are of the same type and have the same height (thickness), then they can simply be mounted and arranged on a flat substrate 40. Furthermore, since the end faces of the multiple cores 51 all need to be arranged on the second plane P2, there is no need to adjust the position of the end faces of these cores 51 in the front-to-back direction (Z-axis direction). As described above, if the optical fiber 50 is a multi-core fiber and the end faces of the multiple cores 51 are already included in the same plane, then the end faces of these cores 51 can be easily positioned at their respective second focal points F2.

[0055] As shown in Figures 4 and 6, the multiple first lenses 21 and the multiple second lenses 22 are integrally arranged on the light guide member 20.

[0056] With this configuration, the positional relationship between the multiple first lenses 21 and the multiple second lenses 22 can be fixed, thereby suppressing the loss of light L1 (optical signal) due to misalignment of these lenses. Furthermore, by installing the light guide member 20 on the support member 10, the lenses of each group can be installed on the support member 10, thus simplifying the installation work of these lenses on the support member 10.

[0057] As described above, the multiple first lenses 21 and the multiple second lenses 22 are integrally formed on the light guide member 20 by glass molding or the like.

[0058] This configuration allows for the easy formation of a light guide member 20 having multiple first lenses 21 and multiple second lenses 22.

[0059] As shown in Figures 2, 5, and 6, the optical system 1 includes a support member 10 that supports the light guide member 20 and the substrate 40 on which a plurality of light-emitting elements 41 are mounted. The support member 10 has a bottom surface 15a (first mounting surface) of a recess 15 on which the light guide member 20 is installed, and an upper surface 11 (second mounting surface) on which the substrate 40 is installed, which is higher than the bottom surface 15a (first mounting surface) by the height of the light guide member 20.

[0060] With this configuration, by installing the substrate on the upper surface 11 (second mounting surface) of the support member 10, multiple light-emitting elements 41 can be positioned at the height of the first focal point F1.

[0061] As shown in Figures 4, 5, and 6, the light guide member 20 has a flat upper surface, and when the light guide member 20 is installed on the bottom surface 15a (first installation surface) of the recess 15, the upper surface of the light guide member 20 is at substantially the same height as the upper surface 11 (second installation surface) of the support member 10.

[0062] With this configuration, the upper surface of the light guide member 20 when it is installed on the bottom surface 15a (first installation surface) of the recess 15 is substantially the same height as the upper surface 11 (second installation surface) of the support member 10. Therefore, by installing the substrate 40 so as to straddle the upper surface of the light guide member 20 and the upper surface 11 (second installation surface) of the support member 10, the substrate 40 can be stably positioned, and each of the multiple light-emitting elements 41 can be positioned at the corresponding first focal point F1.

[0063] As shown in Figure 2, the support member 10 has a rectangular recess 15 into which the light guide member 20 fits, and the bottom surface 15a of the recess 15 constitutes a first installation surface for installing the light guide member 20.

[0064] With this configuration, the light guide member 20 can be positioned vertically by placing it on the bottom surface 15a of the recess 15 that constitutes the first mounting surface. In addition, the light guide member 20 can be positioned in the width direction by being sandwiched between the two inner surfaces of the recess 15 in the width direction (X-axis direction).

[0065] As shown in Figure 2, the support member 10 includes a fiber support portion 14 that supports the end of an optical fiber 50 having a plurality of cores 51, and the fiber support portion 14 has a V-shaped valley that extends along the longitudinal direction of the optical fiber 50.

[0066] With this configuration, as shown in Figure 5, the end of the optical fiber 50 can be aligned with the valley shape of the fiber support portion 14, thereby restricting the end of the optical fiber 50 in both the vertical and horizontal directions while it is installed on the support member 10.

[0067] As shown in Figure 6, the reflective surface 30 is substantially inclined at 45° with respect to the first plane P1 and the second plane P2, and each optical path formed between the plurality of first lenses 21 and the plurality of second lenses 22 is parallel to the first plane P1 and perpendicular to the second plane P2.

[0068] With this configuration, when light-emitting elements 41 with a Gaussian distribution of emission intensity are placed at the position of each first focal point F1, the intensity of light L1 at the incident end face of each core 51 can be brought closer to a Gaussian distribution, as shown in Figures 7(a) and (b). This increases the coupling efficiency of light L1 to each single-mode core 51 and effectively suppresses the loss of light L1 (optical signal).

[0069] As shown in Figures 5 and 6, the optical connector 2 comprises an optical system 1, optical fibers 50 constituting a plurality of cores 51, a plurality of light-emitting elements 41, and a support member 10 that supports the optical system 1, the optical fibers 50, and the plurality of light-emitting elements 41.

[0070] With this configuration, because the optical system 1 is included, the height of the optical connector 2 can be reduced while the transmission path of the optical signal in the optical connector 2 can be made longer.

[0071] As shown in Figure 6, the optical fiber 50 is a multicore fiber having multiple cores 51.

[0072] With this configuration, by installing one optical fiber 50 on the support member 10, multiple cores 51 for transmitting optical signals can be arranged, and the end faces of these cores 51 can be positioned at multiple second focal points F2 on the second plane P2.

[0073] As described above, each of the multiple light-emitting elements 41 is a surface-emitting laser.

[0074] With this configuration, by using a surface-emitting laser with a small emission angle as the light-emitting element 41, the beam diameter of the light L1 incident on the first lens 21 can be reduced. This allows the effective diameter of each first lens 21 to be reduced, and as a result, the increase in the height of the optical system 1 and the optical connector 2 can be suppressed.

[0075] As described above, it is preferable that the wavelength of light emitted from the multiple light-emitting elements 41 falls within the range of 850 nm to 1550 nm.

[0076] This allows for smooth transmission of optical signals while suppressing signal loss.

[0077] <Example of Modification> Figure 8 is a schematic cross-sectional view showing the configuration of the optical connector 2 according to an example of modification of Embodiment 1.

[0078] Similar to Figure 6, Figure 8 also shows a cross-sectional view of the optical connector 2 when the optical connector 2 has only one optical system 1.

[0079] In the above embodiment 1, four light-emitting elements 41 were arranged on the substrate 40, but in the modified example in Figure 8, four light-receiving elements 43 are arranged on the substrate 40. The four light-receiving elements 43 are, for example, PDs (photodetectors). These light-receiving elements 43 are of the same type and have equal height (thickness). The arrangement of the four light-receiving elements 43 is the same as the arrangement of the light-emitting elements 41 in Figure 6. The configuration is the same as the configuration shown in Figure 6, except that the four light-emitting elements 41 are replaced with four light-receiving elements 43.

[0080] In this modified example, light L1 (optical signal) is emitted from the end face of each core 51. The emitted light L1 travels in the reverse direction along the same optical path as in Figure 6 and is focused onto the photodetector 43. As a result, the photodetector 43 outputs an electrical signal modulated according to the light L1 (optical signal). This electrical signal is output to the circuit section via the wiring 13.

[0081] According to the configuration in Figure 8, although the mode of transmission and reception of optical signals differs, the same effects as in Embodiment 1 can be generally achieved. In the configuration of Figure 8, the optical system 1 and optical connector 2 can be made lower in height while the transmission path of optical signals in the Z-axis direction can be made longer.

[0082] <Embodiment 2> Figure 9 is a schematic cross-sectional view showing the configuration of the optical connector 2 according to Embodiment 2.

[0083] Similar to Figure 6, Figure 9 also shows a cross-sectional view of the optical connector 2 when the optical connector 2 has only one optical system 1.

[0084] In Embodiment 2, the arrangement of the cores 51 in the second plane P2 is different from that of Embodiment 1. That is, in Embodiment 2, the end of the optical fiber 50 is installed on the support member 10 rotated by 45° around the central axis of the optical fiber 50 from the state shown in Figure 6. For this reason, four second lenses 22 are arranged on the negative Z-axis side of the light guide member 20, each facing one of the four cores 51, and four first lenses 21 are arranged on the positive Z-axis side of the light guide member 20, each aligned with the four second lenses 22 in the Z-axis direction. Four light-emitting elements 41 are arranged on the substrate 40 at the positions of the first focal points F1 of each of the four first lenses 21. The centers of the incident end faces of the four cores 51 coincide with the second focal points F2 of each of the four second lenses 22.

[0085] Similar to Embodiment 1 described above, the optical axes of the first lens 21 and the second lens 22, which are aligned in the X-axis direction, are aligned with each other, and these optical axes are aligned with the central axis of the core 51 facing the second lens 22. The first lens 21, the second lens 22, and the core 51, which are aligned in the Z-axis direction, and the light-emitting element 41, which is positioned at the first focal point F1 of the first lens 21, form a single optical signal transmission system.

[0086] In the configuration of Embodiment 2, the inclination angle θ1 of the reflective surface 30 is set to 45°, the same as in Embodiment 1. Therefore, the intensity distribution of the light L1 (optical signal) emitted from each of the four light-emitting elements 41 is a Gaussian distribution over the entire circumference on the incident end face (second plane P2) of the corresponding core 51, similar to Figures 7(a) and (b). Thus, similar to Embodiment 1, each second lens 22 focuses the light L1 to the incident end face of the corresponding core 51 with a beam diameter approximately equal to the MFD of the corresponding core 51, thereby effectively suppressing optical loss when light L1 is incident from the optical system 1 to the core 51.

[0087] Thus, even with the configuration of Embodiment 2, it is possible to transmit a large amount of optical signal through four transmission systems while suppressing the loss of optical signals.

[0088] In the second embodiment, as in the modified example in Figure 8, four light-receiving elements 43 may be arranged on the substrate 40 in place of four light-emitting elements 41. This allows for the configuration of an optical connector 2 for receiving optical signals from the core 51.

[0089] <Effects of Embodiment 2> The same effects as those of Embodiment 1 can be achieved with the configuration of Embodiment 2.

[0090] <Embodiment 3> Figure 10 is a schematic cross-sectional view showing the configuration of the optical connector 2 according to Embodiment 3.

[0091] Similar to Figure 6, Figure 10 also shows a cross-sectional view of the optical connector 2 when the optical connector 2 has only one optical system 1.

[0092] Compared to Embodiment 1 described above, Embodiment 3 has a tilt angle θ2 of the reflective surface 30 changed to 35°. Accordingly, in Embodiment 3, the arrangement of the four first lenses 21 is changed from the arrangement in Figure 6, and furthermore, the four first lenses 21 and the four second lenses 22 are tilted in a direction parallel to the Y-Z plane from the state in Figure 6. Also, the focal lengths of the two upper first lenses 21 and the two lower first lenses 21 are different so that the four first focal points F1 are formed on the first plane P1. The configuration of the optical connector 2 other than this is the same as the configuration in Figure 6. The tilt angle θ2 only needs to be substantially 35°.

[0093] The four second lenses 22 each face the four cores 51. The four first lenses 21 parallelize the light L1 emitted from each of the four light-emitting elements 41 and reflected by the reflective surface 30, and guide it to each of the four second lenses 22. In Embodiment 3, since the inclination angle θ2 is 35°, the light L1 emitted from the four light-emitting elements 41 is incident on the Z-axis positive side of the light guide member 20 at a lower position than in Figure 6. For this reason, the four first lenses 21 are positioned at a lower position than in Figure 6.

[0094] On the other hand, the four second lenses 22 focus the light L1 onto the incident end faces of the four cores 51 so that the central axis of the light L1 coincides with the central axis of the four cores 51, and then direct the light into each core 51. For this reason, the four second lenses 22 are arranged in the Z-axis direction with respect to the incident end faces of the four cores 51. Therefore, the arrangement of the four second lenses 22 is substantially the same as in the case of Figure 6.

[0095] As shown above, in the configuration of Figure 10, the positions of the four first lenses 21 and the four second lenses 22 are offset in the height direction (Y-axis direction). Therefore, the lens surfaces (incident surfaces) of the four first lenses 21 have a surface shape that directs each of the incident light L1, which is reflected by the reflection surface 30, towards the four second lenses 22 while making it parallel light. Furthermore, the lens surface (exit surface) of each second lens 22 has a surface shape that bends the optical path of the incident light L1 in a direction parallel to the Y-Z plane so that the central axis of the incident light L1 aligns with the central axis of the corresponding core 51, and positions the second focal point F2 of this light L1 on the incident end face (second plane P2) of the core 51.

[0096] Figure 11 is a graph showing the simulation results of the light intensity distribution L1 at the incident end faces of the two lower cores 51 out of the four cores 51. Figure 12 is a graph showing the simulation results of the light intensity distribution L1 at the incident end faces of the two upper cores 51 out of the four cores 51.

[0097] As shown in Figures 11 and 12, in both the lower core 51 and the upper core 51, the light L1 at the incident end face has a beam shape that is slightly compressed in the Y-axis direction, and the intensity distribution is also slightly deviated from the Gaussian distribution. For this reason, in the configuration of Embodiment 3, the optical coupling efficiency between the light L1 and the core 51 is slightly lower compared to Embodiment 1, and some optical loss may occur when the light L1 is incident from the optical system 1 to the core 51.

[0098] Furthermore, as can be seen by comparing Figures 11 and 12, the peak intensity of light L1 at the incident end face of the upper core 51 is slightly lower than the peak intensity of light L1 at the incident end face of the lower core 51. For this reason, in the configuration of Embodiment 3, the utilization efficiency of light L1 incident on the upper core 51 may be slightly lower compared to Embodiment 1.

[0099] Thus, in the configuration of Embodiment 3, by changing the inclination angle θ2 of the reflective surface 30 to 35°, the utilization efficiency of light L1 may be slightly reduced compared to Embodiment 1. However, even in the configuration of Figure 8 according to Embodiment 3, it is possible to lengthen the optical signal transmission path in the Z-axis direction while achieving a lower profile for the optical system 1 and the optical connector 2.

[0100] In Embodiment 3, as in the modified example in Figure 8, four light-receiving elements 43 may be arranged on the substrate 40 in place of the four light-emitting elements 41. This allows for the configuration of an optical connector 2 for receiving optical signals from the core 51.

[0101] <Effects of Embodiment 3> According to the configuration of Embodiment 3, although the utilization efficiency of light L1 is slightly reduced as described above, the same effects as those of Embodiment 1 can be generally achieved.

[0102] Furthermore, in the configuration of Embodiment 3, as shown in Figure 10, the reflective surface 30 is positioned on the support member 10, the reflective surface 30 is substantially inclined at 35° with respect to the first plane P1, and each optical path between the four first lenses 21 and the four second lenses 22 is inclined with respect to the first plane P1.

[0103] As described above, when the support member 10 is made of silicon, the accuracy of the inclination and height of the inclined surface of the support member 10 on which the reflective surface 30 is placed can be maximized when the inclined surface of the support member 10 is substantially inclined at 35° with respect to the first plane P1, due to the relationship with the crystal orientation of silicon. Therefore, by setting the inclination angle θ2 of the reflective surface 30 to 35° as described above, the reflective surface 30 can be accurately positioned at the target inclination and height, and optical signals can be transmitted smoothly.

[0104] <Embodiment 4> In embodiments 1 to 3 described above, the light guide member 20 was fitted into the recess 15 shown in Figure 2, and the light guide member 20 was installed on the support member 10. In contrast, embodiment 4 shows various installation configurations for installing the light guide member 20 on the support member 10. These installation configurations will be described below with reference to Figures 13(a) to 20.

[0105] The following describes the installation configuration of the light guide member 20 when the optical fiber 50 is installed on the support member 10 and the four cores 51 are arranged as in embodiments 1 and 3 described above. Therefore, in the following installation configuration, when the light guide member 20 is installed on the support member 10, the light guide member 20 and the installation surface are configured such that the four first lenses 21 and the four second lenses 22 are arranged in pairs in the vertical and horizontal directions, respectively.

[0106] Figures 13(a) to 13(c) and 14(a) to 14(c) schematically show various installation configurations for mounting the light guide member 20 to the support member 10, respectively.

[0107] These figures schematically show the configuration of the parts related to each installation configuration when viewed in the positive Z-axis direction. In each figure, the support member 10 is hatched. The upper part of each figure shows the state before the light guide member 20 is installed, and the lower part of each figure shows the state after the light guide member 20 is installed.

[0108] <Installation Configuration 1> In the installation configuration shown in Figure 13(a), the installation surface 16 of the support member 10 on which the light guide member 20 is installed has a surface shape in the width direction (X-axis direction) of the light guide member 20, where the center is lower than both ends. Here, the installation surface 16 has a V-shaped groove. The positive and negative ends of this groove shape along the Z axis are open.

[0109] When viewed in the Z-axis direction, the shape of the light guide member 20 is that of a circle with a portion cut out. That is, the light guide member 20 has a shape in which the outer circumference of a cylinder is cut out by a plane parallel to the central axis of the cylinder. Therefore, the light guide member 20 has a single flat upper surface 23 that is parallel to the central axis of the cylinder.

[0110] Four second lenses 22 are arranged on the negative Z-axis side of the light guide member 20, and four first lenses 21 (not shown) are arranged on the negative Z-axis side of the light guide member 20. The arrangement of these first lenses 21 and second lenses 22 is the same as in embodiments 1 and 3 described above. Two second lenses 22 are arranged along two rows parallel to the upper surface 23, and two second lenses 22 are arranged along two columns perpendicular to the upper surface 23. The four first lenses 21 (not shown) are similarly arranged along two rows and two columns.

[0111] The light guide member 20 is placed on the mounting surface 16 such that its upper surface 23 is parallel to the X-Z plane. At this time, adhesive 60 is applied to the gap between the light guide member 20 and the mounting surface 16. The adhesive 60 is preferably a highly viscous epoxy resin. Furthermore, the upper limit of the usable temperature range of the adhesive 60 is preferably high, up to about 100°C. With this installation, the four first lenses 21 and the four second lenses 22 are arranged in the same state as in Figure 6 or Figure 10.

[0112] Furthermore, in the installation state shown in the lower part of Figure 13(b), the upper surface 23 of the light guide member 20 is substantially the same height as the upper surface 11 of the support member 10 (see Figure 1), that is, the installation surface of the substrate 40 (second installation surface). The size of the light guide member 20 and the height of the upper surface 23 are set so as to satisfy this condition.

[0113] According to this installation configuration, the installation surface 16 (first installation surface) has a surface shape in the width direction (X-axis direction) of the light guide member 20 where the center is lower than both ends.

[0114] As a result, the light guide member 20 is restricted in the width direction (a direction parallel to both the first plane P1 and the second plane P2) by the surface shape of the installation surface 16 (first installation surface), so the light guide member 20 can be positioned in the width direction.

[0115] Furthermore, the light guide member 20 has a flat upper surface 23, and when the light guide member 20 is installed on the installation surface 16 (first installation surface), the upper surface 23 is substantially the same height as the upper surface 11 (second installation surface) of the support member 10.

[0116] Thus, since the upper surface 23 of the light guide member 20 when installed on the installation surface 16 (first installation surface) is substantially the same height as the upper surface 11 (second installation surface) of the support member 10, the substrate 40 can be stably positioned by installing it so as to straddle the upper surface 23 of the light guide member 20 and the upper surface 11 (second installation surface) of the support member 10, and each of the multiple light-emitting elements 41 can be positioned at the corresponding first focal point F1.

[0117] <Installation Configuration 2> In the installation configuration shown in Figure 13(b), the shape of the light guide member 20 differs from that of installation configuration 1. Specifically, the light guide member 20 has a shape in which the corners of a rectangular prism are cut out by a single plane parallel to the central axis of the rectangular prism. Therefore, the light guide member 20 has a single flat upper surface 23 parallel to the central axis of the rectangular prism. The lower surface of the light guide member 20 has a V-shape similar to that of the installation surface 16. Therefore, when the light guide member 20 is installed on the installation surface 16, the lower surface of the light guide member 20 and the surface shape of the installation surface 16 engage with each other.

[0118] In this installation configuration, the same adhesive 60 as described above is applied to the boundary between the light guide member 20 and the support member 10. In this installation configuration as well, when the light guide member 20 is installed, the upper surface 23 of the light guide member 20 is parallel to the X-Z plane and is at substantially the same height as the upper surface 11 of the support member 10 (see Figure 1), i.e., the installation surface of the substrate 40 (second installation surface). The size of the light guide member 20 and the height of the upper surface 23 are set so as to satisfy these conditions.

[0119] In this installation configuration, the installation surface 16 (first installation surface) has a surface shape in the width direction (X-axis direction) of the light guide member 20 where the center is lower than both ends, and the lower surface of the light guide member 20 has a surface shape that engages with the surface shape of the installation surface 16 (first installation surface).

[0120] In this way, since the lower surface of the light guide member 20 engages with the surface shape of the mounting surface 16 (first mounting surface), the light guide member 20 can be positioned not only in the lateral direction but also in the rotational direction. Therefore, the light guide member 20 can be installed on the support member 10 with high precision, and the loss of optical signals due to misalignment of the multiple first lenses 21 and multiple second lenses 22 can be suppressed. Furthermore, similar to the mounting configuration 1, the effects of the upper surface 23 can also be achieved.

[0121] <Installation Configuration 3> In the installation configuration shown in Figure 13(c), the shape of the light guide member 20 differs from that of installation configuration 1. Specifically, the cross-section of the light guide member 20 when cut by a plane parallel to the X-Y plane is a pentagon (a so-called home plate shape) at any position along the length direction (Z-axis direction) of the light guide member 20. The light guide member 20 has a symmetrical shape in the width direction (X-axis direction).

[0122] The lower surface of the light guide member 20 has the same V-shape as the mounting surface 16. Therefore, when the light guide member 20 is installed on the mounting surface 16, the lower surface of the light guide member 20 and the surface shape of the mounting surface 16 engage with each other. Similar to the installation configuration 2 described above, the same adhesive 60 as described above is applied to the boundary between the light guide member 20 and the support member 10.

[0123] The upper surface 23 of the light guide member 20 is a single plane. When the light guide member 20 is installed on the installation surface 16, the upper surface 23 is parallel to the X-Z plane and is at substantially the same height as the upper surface 11 of the support member 10 (see Figure 1), i.e., the installation surface of the substrate 40 (second installation surface). The size of the light guide member 20 and the height of the upper surface 23 are set so as to satisfy this condition.

[0124] This installation configuration can achieve the same effects as the installation configuration 3 described above.

[0125] <Installation Configuration 4> In the installation configuration shown in Figure 14(a), the shape of the light guide member 20 differs from that of installation configuration 1. Specifically, a plane 24 is formed on the outer circumference of the light guide member 20, which is cut out by another plane parallel to the central axis of the light guide member 20. The other configurations of installation configuration 4 are the same as those of installation configuration 1.

[0126] As shown in the lower part of Figure 14(a), when the light guide member 20 is installed on the installation surface 16, the plane 24 engages with one of the inclined surfaces of the V-shaped installation surface 16. This further defines that the light guide member 20 rotates about its central axis, thereby positioning the light guide member 20 in a predetermined position.

[0127] In installation configuration 4, when the light guide member 20 is installed on the installation surface 16, the upper surface 23 is parallel to the X-Z plane and is at substantially the same height as the upper surface 11 of the support member 10 (see Figure 1), i.e., the installation surface of the substrate 40 (second installation surface). The size of the light guide member 20, the height of the upper surface 23, and the position and inclination of the plane 24 are set so as to satisfy this condition.

[0128] This installation configuration can achieve the same effects as the installation configuration 3 described above.

[0129] <Installation Configuration 5> The installation configuration shown in Figure 14(b) is modified by adding a notch 17 for applying adhesive 60 to the recess 15 in Embodiment 1. The other configurations of Installation Configuration 5 are the same as those of Embodiment 1. The notch 17 is formed by cutting out rectangular sections in the upper two corners of the recess 15 in Embodiment 1, within the area of ​​the recess 15 where the light guide member 20 is installed. As shown in the lower part of Figure 14(b), the adhesive 60 is applied to these notches 17, and the light guide member 20 is fixed to the support member 10. The adhesive 60 does not necessarily have to be applied along the entire length of the notch 17.

[0130] In this installation configuration, the support member 10 has a rectangular recess 15 into which the light guide member 20 fits, and the bottom surface 15a of the recess 15 constitutes the installation surface (first installation surface) of the light guide member 20.

[0131] As a result, by placing the light guide member 20 on the bottom surface 15a of the recess 15 that constitutes the first mounting surface, the light guide member 20 can be positioned in the vertical direction. Furthermore, by sandwiching the light guide member 20 between the two inner surfaces of the recess 15, the light guide member 20 can be positioned in the width direction. In addition, the adhesive 60 can be smoothly applied by the notch 17. Moreover, the effects of the top surface 23 can also be achieved, similar to the mounting configuration 1.

[0132] <Installation Configuration 6> In the installation configuration shown in Figure 14(c), the shape of the light guide member 20 differs from that of installation configuration 5. Specifically, in this installation configuration 6, the light guide member 20 shown in Figure 13(a) is installed in the recess 15. When the light guide member 20 is installed on the bottom surface 15a (installation surface) of the recess 15, the top surface 23 is parallel to the X-Z plane and is at substantially the same height as the top surface 11 of the support member 10, i.e., the installation surface of the substrate 40 (second installation surface). The size of the light guide member 20, the height of the top surface 23, and the depth of the recess 15 are set so as to satisfy these conditions.

[0133] In this installation configuration 6 as well, the adhesive 60 described above is applied to the two notches 17, and the light guide member 20 is fixed to the support member 10. The adhesive 60 flows from the notches 17 into the recesses 15 and reaches the outer circumference of the light guide member 20. The adhesive 60 does not necessarily have to be applied along the entire length of the notches 17.

[0134] This installation configuration can achieve the same effects as installation configuration 5.

[0135] <Installation Configuration 7> Figures 15(a) and 15(b) are schematic side and plan views, respectively, showing the configuration for installing the light guide member 20 on the support member 10 according to Installation Configuration 7.

[0136] Figure 15(a) schematically shows the configuration of the parts related to the installation configuration when viewed in the positive Z-axis direction. In Figure 15(a), the support member 10 is hatched. The upper part of Figure 15(a) shows the state before the light guide member 20 is installed, and the lower part of each figure shows the state after the light guide member 20 is installed. Figure 15(b) schematically shows the configuration of the area related to the installation configuration and its periphery when viewed from above. In Figure 15(b), the upper surface 11 of the support member 10 is hatched.

[0137] As shown in Figures 15(a) and (b), in installation configuration 7, three light guide members 20 are installed in one recess 18. Three bases 18a are arranged on the bottom surface of the recess 18, one for each area where a light guide member 20 is installed. In Figure 15(b), the installation areas for each light guide member 20 are shown separated by dashed lines. These bases 18a are integrally formed with the support member 10. The heights of these bases 18a are equal to each other. The configuration of each light guide member 20 is the same as in embodiment 1 or 3 described above.

[0138] As shown in Figure 15(a), the three light guide members 20 are placed on their corresponding bases 18a and installed on the support member 10. At this time, the adhesive 60 described above is applied between the lower surface of each light guide member 20 and the bottom surface of the recess 18. The adhesive 60 may be applied to the entire gap between the two bases 18a on the negative Z-axis side, or it may be applied to the area near the side walls of the bases 18a within this gap. Furthermore, before the adhesive 60 hardens, these light guide members 20 are positioned in the X-axis direction so that the four second lenses 22 are properly positioned at the locations of the four cores 51 of the corresponding optical fiber 50. In this way, the three light guide members 20 are installed in one recess 18.

[0139] With the three light guide members 20 installed, the upper surface 23 of each light guide member 20 is parallel to the X-Z plane and is at substantially the same height as the upper surface 11 of the support member 10, i.e., the mounting surface (second mounting surface) of the substrate 40. The depth of the recess 15 and the height of the base 18a are set so as to satisfy this condition.

[0140] In this installation configuration 7, as shown in Figure 15(b), a single reflective surface 30 common to the three light guide members 20 may be positioned on the back side (positive Z-axis side) of the installation area of ​​the three light guide members 20. This simplifies the configuration.

[0141] The number and size of the bases 18a placed in the installation area of ​​each light guide member 20 are not limited to those shown in Figures 15(a) and (b), and can be changed as appropriate, as long as the light guide member 20 can be supported stably and properly. As shown in Figures 15(a) and (b), the light guide member 20 can be supported stably and properly by supporting it at three points.

[0142] <Installation Configuration 8> Figures 16(a) and 16(b) are schematic side and plan views, respectively, showing the configuration for installing the light guide member 20 on the support member 10 according to Installation Configuration 8. Similar to Figures 15(a) and 15(b), Figures 16(a) and 16(b) show side and plan views of parts related to the installation configuration.

[0143] In installation configuration 8, the configuration of the recesses 18 differs from that of installation configuration 7. Specifically, in installation configuration 7, one recess 18 common to the three light guide members 20 was provided, but in installation configuration 8, a recess 18 is provided for each light guide member 20. Adjacent recesses 18 are separated by a wall. The height of the wall is equal to the depth of the recess 18. However, the height of the wall may be less than the depth of the recess. Three bases 18a are provided on the bottom surface of each recess 18.

[0144] The width of each recess 18 (dimension in the X-axis direction) is slightly larger than the width of each light guide member 20 (dimension in the X-axis direction). Each light guide member 20 is inserted into each recess 18 from above, with both sides in the X-axis direction substantially in contact with both sides of the corresponding recess 18 in the X-axis direction. In this state, with the three light guide members 20 installed, the upper surface 23 of each light guide member 20 is parallel to the X-Z plane, as in the cases of Figures 15(a) and (b), and is at substantially the same height as the upper surface 11 of the support member 10, i.e., the installation surface of the substrate 40 (second installation surface).

[0145] With this installation configuration, since a recess 18 is provided for each light guide member 20, the light guide member 20 can be easily installed in a predetermined position by inserting it into the corresponding recess 18.

[0146] In addition, even in installation configuration 8, the number and size of the bases 18a placed in the installation area of ​​each light guide member 20 are not limited to the number and size shown in Figures 16(a) and (b), and can be changed as appropriate, as long as the light guide member 20 can be supported stably and properly.

[0147] <Installation Configuration 9> Figures 17(a) and 17(b) are schematic side and plan views, respectively, showing the configuration for installing the light guide member 20 on the support member 10 according to Installation Configuration 9. Similar to Figures 15(a) and 15(b), Figures 17(a) and 17(b) show side and plan views of parts related to the installation configuration.

[0148] In installation configuration 9, the configuration of the recesses 18 differs from that of installation configuration 8. Specifically, in installation configuration 8, three bases 18a were placed in each recess 18, but in installation configuration 9, grooves 18b are formed on the bottom surface of the recess 18 instead of the three bases 18a. When each light guide member 20 is placed on the bottom surface of the corresponding recess 18, the height of the upper surface of these light guide members 20 is substantially the same as the height of the upper surface 11 of the support member 10. As shown in Figure 17(b), the grooves 18b extend over the entire length of the recess 18 (in the Z-axis direction). In installation configuration 9, each light guide member 20 is fixed to the corresponding groove 18b by applying the adhesive 60 described above to each groove 18b.

[0149] Even with this installation configuration, since a recess 18 is provided for each light guide member 20, the light guide member 20 can be easily installed in a predetermined position by inserting it into the corresponding recess 18.

[0150] <Installation Configuration 10> Figures 18(a) and 18(b) are schematic side and plan views, respectively, showing the configuration for installing the light guide member 20A on the support member 10 according to installation configuration 10. Similar to Figures 15(a) and 15(b), Figures 18(a) and 18(b) show side and plan views of parts related to the installation configuration.

[0151] In installation configuration 10, the configuration of the light guide member 20A and the recess 18 differs from that of installation configuration 9. Specifically, the three light guide members 20 described above are integrated into a single light guide member 20A. Three sets of four second lenses 22 are arranged on the Z-axis negative side of the light guide member 20A, which is wide in the X-axis direction and has a rectangular parallelepiped shape. Three sets of four first lenses 21 (not shown) are arranged on the Z-axis positive side of this light guide member 20A. The configuration and positional relationship of each set of first lenses 21 and the corresponding set of second lenses 22 are the same as in embodiments 1 and 3. The positional relationship between each set of four second lenses 22 and the corresponding four cores 51 of the optical fiber 50 is also the same as in embodiments 1 and 3.

[0152] The support member 10 has a recess 18 into which the light guide member 20A fits. Three grooves 18b, similar to those in the installation configuration 9, are formed on the bottom surface of the recess 18. The number of grooves 18b is not limited to three; other numbers may be used. In this case, the width of the grooves 18b may be changed as appropriate.

[0153] The width of the recess 18 (dimension in the X-axis direction) is slightly larger than the width of the light guide member 20A (dimension in the X-axis direction). The light guide member 20A is inserted into the recess 18 from above, with both sides in the X-axis direction substantially in contact with both sides of the recess 18 in the X-axis direction. In this state, with the light guide member 20A installed, the upper surface 23 of the light guide member 20A is parallel to the X-Z plane and is at substantially the same height as the upper surface 11 of the support member 10, i.e., the installation surface (second installation surface) of the substrate 40.

[0154] With this installation configuration, by installing one light guide member 20A in the recess 18, three sets of first lenses 21 and three sets of second lenses 22 can be arranged simultaneously.

[0155] <Installation Configuration 11> Figures 19(a) and 19(b) are schematic side and plan views, respectively, showing the configuration for installing the light guide member 20B on the support member 10 according to installation configuration 11. Similar to Figures 15(a) and 15(b), Figures 19(a) and 19(b) show side and plan views of parts related to the installation configuration.

[0156] In installation configuration 11, the configuration of the light guide member 20B and the recess 18 differs from that of installation configuration 10. Specifically, the recess 18 is divided into three regions by two walls 18c. The height of the walls 18c is lower than the height of the top surface 11. When viewed in the Y-axis direction, the shape of the walls 18c is rectangular, and the top surface of the walls 18c is parallel to the X-Z plane.

[0157] Furthermore, the light guide member 20B has a configuration in which the three light guide members 20 shown in Figure 17(a) are connected at the top and integrated. The light guide member 20B is integrally formed with three sets of first lenses 21 (not shown) and three sets of second lenses 22. The other configurations in installation configuration 11 are the same as those in installation configuration 10.

[0158] As shown in the lower part of Figure 19(a), when the light guide member 20B is installed, the upper surface 23 of the light guide member 20B is parallel to the X-Z plane and is at substantially the same height as the upper surface 11 of the support member 10, i.e., the installation surface (second installation surface) of the substrate 40. Also, at the positions of the two walls 18c, the lower surface of the light guide member 20B is in substantially contact with the upper surfaces of these walls 18c. The height of each wall 18c and the thickness of the light guide member 20 in the range corresponding to each wall 18c are set so that these conditions are met. In this installation configuration as well, the light guide member 20 is fixed in the recess 18 by the adhesive 60 applied to the groove 18b.

[0159] With this installation configuration, by installing one light guide member 20A in the recess 18, three sets of first lenses 21 and three sets of second lenses 22 can be arranged simultaneously.

[0160] <Installation Configuration 12> Figure 20 is a schematic side view and plan view showing the configuration for installing the light guide member 20C on the support member 10 according to installation configuration 12. Similar to Figure 15(a), Figure 20 shows a side view of the part related to the installation configuration.

[0161] The light guide member 20C has a configuration in which three light guide members 20, as shown in Figure 13(a), are arranged in the X-axis direction, and these light guide members 20 are connected at the top to form a single unit. Therefore, the lower surface of the light guide member 20C has three arc-shaped portions. The upper surface of the light guide member 20C is a single plane parallel to the X-Z plane. The light guide member 20C is integrally formed with three sets of first lenses 21 (not shown) and three sets of second lenses 22. Each set of first lenses 21 and second lenses 22 are positioned within the range corresponding to their respective arc-shaped portions.

[0162] The support member 10 has three mounting surfaces 16 arranged in the X-axis direction, each having the same configuration as shown in Figure 13(a). The distance between adjacent mounting surfaces 16 is equal to the distance between adjacent arc portions of the light guide member 20C. The light guide member 20C is installed on the support member 10 such that each arc portion fits into the corresponding mounting surface 16. At this time, adhesive 60 is applied to the gap between the mounting surface 16 and the arc portion. Furthermore, adhesive 60 may also be applied to the gap between the lower surface of the portion of the light guide member 20 that connects adjacent arc portions and the support member 10. In this way, the light guide member 20C is fixed to the support member 10.

[0163] In this case as well, when the light guide member 20C is installed on the support member 10, the height of the upper surface of the light guide member 20C is substantially equal to the height of the upper surface of the support member 10. As a result, the substrate 40 can be installed smoothly, similar to Embodiment 1 above.

[0164] Although installation configurations 1 to 12 have been described above, the installation configuration of the light guide member is not limited to those described above. Furthermore, if the four cores 51 are arranged along a cross shape as in Embodiment 2 above, the layout of the four first lenses 21 and the four second lenses 22 in installation configurations 1 to 12 may be the same as that in Embodiment 2 above.

[0165] <Other Modification Examples> In embodiments 1 to 3 described above, the first lens 21 and the second lens 22 were shown as single-surface refractive lenses, but the first lens 21 and the second lens 22 may be Fresnel lenses or diffracting lenses.

[0166] Furthermore, in embodiments 1 to 3 described above, four cores 51 were arranged in one optical fiber 50, but the number of cores 51 arranged in the optical fiber 50 is not limited to this, and multiple cores 51 other than four may be arranged in the optical fiber 50. In this case, it is sufficient to arrange a number of first lenses 21 and second lenses 22 corresponding to the number of cores 51.

[0167] Furthermore, in embodiments 1 to 3 described above, a plurality of first lenses 21 and a plurality of second lenses 22 were arranged on both sides of the light guide member 20, respectively. However, the method of arranging these first lenses 21 and second lenses 22 is not limited to this. For example, a first lens array having a plurality of first lenses 21 and a second lens array having a plurality of second lenses 22 may be individually arranged on the support member 10.

[0168] However, in this case, when installing multiple first arrays and multiple second lens arrays, it is necessary to adjust the relative positions of the lenses. In contrast, in embodiments 1 to 3 described above, since the multiple first lenses 21 and multiple second lenses 22 are integrated into the light guide member 20 with their relative positions already adjusted, such position adjustment is not necessary. Therefore, in embodiments 1 to 3 described above, the multiple first lenses 21 and multiple second lenses 22 can be installed on the support member 10 more easily and accurately.

[0169] Furthermore, in embodiments 1 to 3 described above, the four first focal points F1 were included in the first plane P1, but the four first focal points F1 do not need to be strictly included in the first plane P1; it is sufficient if they are substantially included in the first plane P1. Similarly, the four second focal points F2 do not need to be substantially included in the second plane P2. The first plane P1 and the second plane P2 do not need to be strictly orthogonal; it is sufficient if they are substantially orthogonal.

[0170] Furthermore, if the light-emitting points of the four light-emitting elements 41 are different from each other in the Y-axis direction, the first focal points F1 of the four first lenses 21 are not included in the first plane P1, but can be formed at the height of each light-emitting point of the four light-emitting elements 41. Similarly, if the end faces of the four cores 51 are offset in the Z-axis direction, the second focal points F2 of the four second lenses 22 are not included in the second plane P2, but can be formed at the position of each end face of the four cores 51.

[0171] Furthermore, the configuration of the optical system 1 and the optical connector 2 is not limited to the configurations shown in embodiments 1 to 3 above, and other configurations are also possible. For example, the number of optical systems 1 arranged in the optical connector 2 is not limited to three, but may be one, two, or four or more. Also, among the multiple optical systems 1 arranged in one optical connector 2, a predetermined optical system 1 may be used for data transmission, and the remaining optical systems 1 may be used for data reception. In this case, a substrate 40 having a light-emitting element 41 is installed in the optical system 1 for data transmission, and a substrate 40 having a light-receiving element 43 is installed in the optical system 1 for data reception.

[0172] Embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical idea set forth in the claims.

[0173] (Note) The above description of embodiments discloses the following technologies.

[0174] (Technical 1) An optical system for transmitting optical signals, comprising: a reflective surface arranged at a predetermined angle with respect to a first plane and a second plane that are substantially orthogonal to each other; a plurality of first lenses arranged between the second plane and the reflective surface, each forming a first focal point on the first plane side via the reflective surface; a plurality of second lenses arranged between the second plane and the plurality of first lenses, each forming a plurality of second focal points on the second plane side, and paired one-to-one with the plurality of first lenses; the end faces of a plurality of cores for optical transmission positioned at the plurality of second focal points; a plurality of light-emitting elements or a plurality of photodetectors positioned at the plurality of first focal points; an optical path for transmitting the optical signal formed between the pair of first lenses and second lenses, and the optical signal transmitted between the core and the light-emitting element or photodetector corresponding to each optical path.

[0175] According to this technology, both the multiple first lenses and the multiple second lenses are positioned between the second plane and the reflective surface, and since these lenses are within the height range of the reflective surface, the height of the optical system can be effectively suppressed. Furthermore, since the light passing through the optical paths formed between the multiple first lenses and the multiple second lenses is substantially parallel light, the optical signal can be transmitted well even if the distance between the multiple first lenses and the multiple second lenses is extended to lengthen these optical paths. Therefore, the optical signal transmission path between the reflective surface and the end faces of the multiple cores, including this optical path, can be lengthened. Thus, the optical system according to Technology 1 makes it possible to lengthen the optical signal transmission path in the optical system while achieving a low profile for the optical system.

[0176] (Technology 2) An optical system according to Technology 1, characterized in that the plurality of first focal points are each formed on the first plane, and the plurality of second focal points are each formed on the second plane.

[0177] According to this technology, since multiple light-emitting elements or multiple photodetectors only need to be arranged on a first plane, if these light-emitting elements or photodetectors are of the same type, or if their height (thickness) is the same, they can simply be mounted and arranged on a flat substrate. Furthermore, since the end faces of multiple cores all need to be arranged on a second plane, there is no need to adjust the position of these end faces in the front-to-back direction. For example, if the end faces of multiple cores, such as in a multicore fiber, are already included in the same plane, these end faces can be easily positioned at their respective second focal points.

[0178] (Technology 3) An optical system according to Technology 1 or 2, characterized in that the plurality of first lenses and the plurality of second lenses are integrally arranged on a light guide member.

[0179] This technology allows the positional relationship between multiple first lenses and multiple second lenses to be fixed, thereby suppressing the loss of optical signals due to misalignment of these lenses. Furthermore, by installing the light guide member on the support member, the lenses of each group can be installed on the support member, simplifying the installation process of these lenses on the support member.

[0180] (Technical 4) An optical system according to Technical 3, characterized in that the plurality of first lenses and the plurality of second lenses are integrally formed with the light guide member.

[0181] This technology makes it possible to easily form a light guide member having multiple first lenses and multiple second lenses.

[0182] (Technical 5) An optical system according to Technical 3 or 4, comprising a support member that supports the light guide member and the plurality of light-emitting elements or the plurality of light-receiving elements mounted on a substrate, wherein the support member has a first mounting surface on which the light guide member is installed, and a second mounting surface on which the substrate is installed, and which is higher than the first mounting surface by the height of the light guide member.

[0183] According to this technology, by installing a substrate on a second mounting surface, multiple light-emitting elements or multiple light-receiving elements can be positioned at the height of the first focal point.

[0184] (Technical 6) An optical system according to Technical 5, wherein the light guide member has a flat upper surface, and when the light guide member is installed on the first installation surface, the upper surface is substantially the same height as the second installation surface.

[0185] According to this technology, since the upper surface of the light guide member when installed on the first installation surface is substantially the same height as the second installation surface, the substrate can be stably positioned by installing it so as to straddle the upper surface of the light guide member and the second installation surface, and each of the multiple light-emitting elements or multiple light-receiving elements can be positioned at the corresponding first focal point.

[0186] (Technical 7) An optical system according to Technical 5, characterized in that the first mounting surface has a surface shape in the width direction of the light guide member, with the center being lower than both ends.

[0187] According to this technology, the light guide member is restricted in the width direction (a direction parallel to both the first and second planes) by the surface shape of the first installation surface, so the light guide member can be positioned in the width direction.

[0188] (Technical 8) An optical system according to Technical 7, characterized in that the lower surface of the light guide member has a surface shape that engages with the surface shape of the first installation surface.

[0189] According to this technology, the lower surface of the light guide member engages with the surface shape of the first mounting surface, allowing the light guide member to be positioned not only laterally but also rotationally. Therefore, the light guide member can be installed on the support member with high precision, and the loss of optical signals due to misalignment of the multiple first lenses and multiple second lenses can be suppressed.

[0190] (Technical 9) An optical system according to Technical 5 or 6, wherein the support member has a rectangular recess into which the light guide member fits, and the bottom surface of the recess constitutes the first mounting surface.

[0191] According to this technology, the light guide member can be positioned vertically by placing it on the bottom surface of the recess that constitutes the first mounting surface. In addition, the light guide member can be positioned horizontally by being sandwiched between the two inner surfaces of the recess.

[0192] (Technical 10) An optical system according to any one of Technical 5 to 9, wherein the support member comprises a fiber support portion that supports the end of at least one optical fiber constituting the plurality of cores, and the fiber support portion has a V-shaped groove extending along the longitudinal direction of the optical fiber.

[0193] This technology allows the end of an optical fiber to be aligned with the valley shape of the fiber support, thereby restricting the end of the optical fiber in both the vertical and horizontal directions while it is installed on the support member.

[0194] (Technical 11) An optical system according to any one of Technical 1 to 10, characterized in that the reflective surface is inclined substantially at 45° with respect to the first plane and the second plane, and each of the optical paths is parallel to the first plane and perpendicular to the second plane.

[0195] According to this technology, when light-emitting elements with a Gaussian emission intensity distribution are positioned at each first focal point, the light intensity at the incident end face of each core can be made to approximate a Gaussian distribution. This increases the coupling efficiency of light to each single-mode core and effectively suppresses optical signal loss.

[0196] (Technical 12) An optical system according to any one of Technical 5 to 10, characterized in that the reflective surface is arranged on the support member, the reflective surface is inclined substantially at 35° with respect to the first plane, and each of the optical paths is inclined with respect to the first plane.

[0197] When the support member is made of silicon, the accuracy of the inclination and height of the inclined surface of the support member on which the reflective surface is placed can be maximized when the inclined surface of the support member is substantially inclined at 35° with respect to the first plane, due to the relationship with the crystal orientation of silicon. Therefore, according to technology 12, the reflective surface can be accurately positioned at the target inclination and height, and optical signals can be transmitted smoothly.

[0198] (Technical 13) An optical connector comprising: an optical system according to any one of Technical 1 to 12; at least one optical fiber constituting the plurality of cores; the plurality of light-emitting elements or the plurality of light-receiving elements; and a support member for supporting the optical system, the optical fiber, and the plurality of light-emitting elements or the plurality of light-receiving elements.

[0199] According to the optical connector of technology 13, since an optical system according to any of technologies 1 to 11 is used, the same effects as those of technologies 1 to 11 can be achieved.

[0200] (Technical 14) An optical connector as described in Technical 13, characterized in that the optical fiber is a multicore fiber having the plurality of cores.

[0201] According to this technology, by installing a single optical fiber in a support member, multiple cores for transmitting optical signals can be arranged, and the end faces of these cores can be positioned at multiple second focal points.

[0202] (Technical 15) An optical connector according to Technical 13 or 14, characterized in that each of the plurality of light-emitting elements is a surface-emitting laser.

[0203] This technology allows for a reduction in the beam diameter of light incident on the first lens by using a surface-emitting laser with a small emission angle as the light-emitting element. This reduces the effective diameter of each first lens, thereby suppressing the increase in height of the optical system and optical connector.

[0204] (Technical 16) An optical connector according to any one of Technical 13 to 15, characterized in that the wavelength of light emitted from the plurality of light-emitting elements is included in the range of 850 nm to 1550 nm.

[0205] This technology allows for the smooth transmission of optical signals while suppressing signal loss.

[0206] 1 Optical system 2 Optical connector 10 Support member 11 Top surface (second mounting surface) 15 Recess 15a Bottom surface (first mounting surface) 16 Mounting surface (first mounting surface) 20, 20A, 20B, 20C Light guide member 21 First lens 22 Second lens 30 Reflecting surface 40 Substrate 41 Light-emitting element 43 Photodetector 50 Optical fiber 51 Core F1 First focus F2 Second focus L1 Light P1 First plane P2 Second plane

Claims

1. An optical system for transmitting optical signals, comprising: a reflective surface arranged at a predetermined angle with respect to a first plane and a second plane that are substantially orthogonal to each other; a plurality of first lenses arranged between the second plane and the reflective surface, each forming a first focal point on the first plane side via the reflective surface; a plurality of second lenses arranged between the second plane and the plurality of first lenses, each forming a plurality of second focal points on the second plane side, and paired one-to-one with the plurality of first lenses; the end faces of a plurality of cores for optical transmission positioned at the plurality of second focal points; a plurality of light-emitting elements or a plurality of photodetectors positioned at the plurality of first focal points; an optical path for transmitting the optical signal formed between the pair of first lenses and second lenses, and the optical signal transmitted between the core and the light-emitting element or photodetector corresponding to each optical path.

2. An optical system according to claim 1, characterized in that the plurality of first focal points are each formed on the first plane, and the plurality of second focal points are each formed on the second plane.

3. An optical system according to claim 1, characterized in that the plurality of first lenses and the plurality of second lenses are integrally arranged on a light guide member.

4. The optical system according to claim 3, characterized in that the plurality of first lenses and the plurality of second lenses are integrally formed with the light guide member.

5. An optical system according to claim 3, comprising a support member that supports the light guide member and the plurality of light-emitting elements or the plurality of light-receiving elements mounted on a substrate, wherein the support member has a first mounting surface on which the light guide member is installed, and a second mounting surface on which the substrate is installed, and which is higher than the first mounting surface by the height of the light guide member.

6. The optical system according to claim 5, wherein the light guide member has a flat upper surface, and when the light guide member is installed on the first installation surface, the upper surface is substantially the same height as the second installation surface.

7. The optical system according to claim 5, characterized in that the first mounting surface has a surface shape in the width direction of the light guide member, where the center is lower than both ends.

8. The optical system according to claim 7, characterized in that the lower surface of the light guide member has a surface shape that engages with the surface shape of the first installation surface.

9. The optical system according to claim 5, wherein the support member has a rectangular recess into which the light guide member fits, and the bottom surface of the recess constitutes the first mounting surface.

10. The optical system according to claim 5, wherein the support member comprises a fiber support portion that supports the end of at least one optical fiber constituting the plurality of cores, and the fiber support portion has a V-shaped groove extending along the longitudinal direction of the optical fiber.

11. The optical system according to claim 1, wherein the reflective surface is inclined substantially at 45° with respect to the first plane and the second plane, and each of the optical paths is parallel to the first plane and perpendicular to the second plane.

12. The optical system according to claim 5, characterized in that the reflective surface is arranged on the support member, the reflective surface is inclined substantially at 35° with respect to the first plane, and each of the optical paths is inclined with respect to the first plane.

13. An optical connector comprising: an optical system according to any one of claims 1 to 12; at least one optical fiber constituting the plurality of cores; the plurality of light-emitting elements or the plurality of light-receiving elements; and a support member for supporting the optical system, the optical fiber, and the plurality of light-emitting elements or the plurality of light-receiving elements.

14. An optical connector according to claim 13, characterized in that the optical fiber is a multicore fiber having the plurality of cores.

15. An optical connector according to claim 13, characterized in that each of the plurality of light-emitting elements is a surface-emitting laser.

16. An optical connector according to claim 13, characterized in that the wavelength of light emitted from the plurality of light-emitting elements is included in the range of 850 nm to 1550 nm.

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