Optical connector

Abstract

This optical connector (1) comprises a first component (10) and a second component (20) that overlap each other, and propagates signal light from a first optical waveguide (100) of the first component (10) to a second optical waveguide (200) of the second component (20) through an overlapping region (R1) between the first component (10) and the second component (20). The first optical waveguide (100) has at least one linear part (110) extending in a Y-axis direction in at least the overlapping region (R1). The second optical waveguide (200) has: a plurality of linear parts (210) that are arranged in an X-axis direction and extend in the Y-axis direction at least in the overlapping region (R1); a single main waveguide part (220) that is disposed on the downstream side in a propagation direction of the signal light; and a connection part (230) that connects the plurality of linear parts (210) and the main waveguide part (220).

Description

Optical connector

[0001] This invention relates to an optical connector for transmitting optical signals.

[0002] In recent years, in order to further increase the speed of signal transmission, methods for transmitting optical signals have been adopted not only for communication between servers constituting a data center, but also for communication within servers themselves. When transmitting optical signals within a server, for example, a laser element and an optical waveguide are connected, and the optical waveguide is further connected to an optical fiber. In this case, it is preferable that the optical waveguide be detachable in order to respond to laser element failure or optical fiber damage.

[0003] Patent Document 1 below describes two optical waveguides formed by a core portion extending in one direction and a cladding layer arranged to surround the core portion, which are then stacked on top of each other. In each optical waveguide, the thickness of the thin portion of the cladding layer located in the direction opposite to the core portion is set to 0 to 0.5 μm. This allows the two stacked optical waveguides to be optically connected to each other, and also allows for the attachment and detachment of these optical waveguides in the event of a malfunction or other problem.

[0004] Japanese Patent Publication No. 2017-134317

[0005] In the above-mentioned Patent Document 1, if a misalignment occurs in a direction parallel to the optical waveguides in two interconnected optical waveguides, the signal light from one optical waveguide is transmitted to the other optical waveguide. However, if a misalignment occurs in a direction perpendicular to the optical waveguides, the coupling between the optical waveguides decreases, resulting in the so-called optical loss problem.

[0006] In view of these problems, the present invention aims to provide an optical connector capable of suppressing optical loss due to misalignment between two optical waveguides.

[0007] A primary aspect of the present invention relates to an optical connector comprising a first component and a second component that overlap each other, for propagating signal light from a first optical waveguide of the first component to a second optical waveguide of the second component via an overlapping region of the first component and the second component. In the optical connector according to this aspect, the first optical waveguide has at least one sending-side linear section extending in a first direction substantially perpendicular to the overlapping direction of the first component and the second component in at least the overlapping region, the second optical waveguide has a plurality of receiving-side linear sections aligned in a second direction perpendicular to the overlapping direction and the first direction in at least the overlapping region and extending in the first direction, a single receiving-side leading wave section located downstream in the propagation direction of the signal light, and a receiving-side connecting section connecting the plurality of receiving-side linear sections and the receiving-side leading wave section.

[0008] According to the optical connector of this embodiment, even if a misalignment occurs between the first and second components, and a misalignment occurs between the first and second optical waveguides in the second direction, the transmitting linear portion approaches one of the multiple receiving linear portions, allowing signal light to propagate from the first optical waveguide to the second optical waveguide. This suppresses optical loss due to misalignment in the second direction. Furthermore, even if a misalignment occurs between the first and second optical waveguides in the first direction, the overlap between the transmitting linear portion and the receiving linear portion is maintained. As a result, optical loss due to misalignment in the first direction is substantially eliminated. Therefore, optical loss due to misalignment between the first and second optical waveguides can be suppressed.

[0009] As described above, the present invention provides an optical connector that can suppress optical loss due to misalignment between two optical waveguides.

[0010] 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.

[0011] Figure 1 is a perspective view showing the configuration of an optical connector according to Embodiment 1. Figure 2 is an internal perspective view of the optical connector according to Embodiment 1, viewed in the negative X-axis direction. Figures 3(a) to 3(c) are cross-sectional views of the optical connector according to Embodiment 1, taken when cut along C21-C22, C31-C32, and C11-C12 in Figure 2, respectively. Figure 4 is a plan view showing the configuration of the optical connector according to Embodiment 1, viewed in the negative Z-axis direction. Figure 5 is a plan view showing the configuration of the optical connector according to a modified example of Embodiment 1, viewed in the negative Z-axis direction. Figure 6 is a plan view showing the configuration of the optical connector according to Embodiment 2, viewed in the negative Z-axis direction. Figure 7 is an internal perspective view of the optical connector according to Embodiment 2, viewed in the negative X-axis direction. Figures 8(a) to 8(c) are cross-sectional views of the optical connector according to Embodiment 2, taken when cut along C21-C22, C31-C32, and C11-C12 in Figure 7, respectively. Figure 9(a) is a graph showing the relationship between the width of the optical waveguide in the X-axis direction and the FWHM of the optical distribution according to Embodiment 2. Figure 9(b) is a diagram illustrating the FWHM of the optical distribution according to Embodiment 2. Figure 10(a) is a graph showing the relationship between the amount of misalignment between two optical waveguides and the coupling coefficient in two adjacent optical waveguides according to Embodiment 2. Figure 10(b) is a diagram illustrating the coupling coefficient according to Embodiment 2. Figure 11 is a plan view showing an example of the width in the X-axis direction of each part of the optical connector according to Embodiment 2. Figure 12 is a side view showing an example of the thickness in the Z-axis direction of each part of the optical connector according to Embodiment 2. Figure 13 is a plan view illustrating a design example of a second optical waveguide according to Embodiment 2. Figure 14 is a graph showing the relationship between the width, misalignment, and maximum number of multiple optical waveguides according to Embodiment 2. Figure 15 is a plan view showing the configuration of the optical connector when viewed in the negative Z-axis direction according to Embodiment 3. Figure 16 is a plan view showing the configuration of the optical connector as viewed in the negative Z-axis direction, according to a modified example of Embodiment 3.

[0012] However, the drawings are for illustrative purposes only and do not limit the scope of this invention.

[0013] Embodiments of the present invention will be described below with reference to the figures. For convenience, mutually orthogonal X, Y, and Z axes are indicated in each figure. In optical connector 1, the positive Z-axis direction is the height direction, the X-axis direction is the short-side direction, and the Y-axis direction is the long-side direction. In the first optical waveguide 100 and the second optical waveguide 200, the Z-axis direction is the thickness direction, the X-axis direction is the width direction, and the Y-axis direction is the extension direction. In the present invention, the "overlap direction" is defined as the "direction parallel to the Z-axis". In the optical connector, the side from which the light is incident is defined as "upstream", and the side from which the light is emitted is defined as "downstream".

[0014] In the following embodiments, the Y-axis direction and the X-axis direction correspond to the "first direction" and "second direction" as described in the claims, respectively. The linear section 110, the leading wave section 120, the connecting section 130, the linear section 210, the leading wave section 220, and the connecting section 230 correspond to the sending-side linear section, the sending-side leading wave section, the sending-side connecting section, the receiving-side linear section, the receiving-side leading wave section, and the receiving-side connecting section, respectively, as described in the claims.

[0015] <Embodiment 1> Figure 1 is a perspective view showing the configuration of the optical connector 1.

[0016] The optical connector 1 comprises a rectangular parallelepiped first component 10 and a second component 20. The first component 10 and the second component 20 are each independently configured. The first component 10 and the second component 20 are configured to be detachable from each other and are installed, for example, on a circuit board in a server, in an overlapping state as shown in Figure 1. The optical connector 1 propagates signal light from the first optical waveguide 100 of the first component 10 to the second optical waveguide 200 of the second component 20 through the overlapping region R1 of the first component 10 and the second component 20.

[0017] The first component 10 consists of a core 11 extending linearly in the Y-axis direction and a cladding 12 covering the core 11. The second component 20 consists of a comb-shaped core 21 and a cladding 22 covering the core 21. The core 21 comprises four parts extending linearly in the Y-axis direction near the negative Y-axis end of the second component 20, one part extending linearly in the Y-axis direction near the positive Y-axis end of the second component 20, and a part connecting these.

[0018] The cores 11 and 21 are made of a polymer with a refractive index of 1.577, for example, and the cladding 12 and 22 are made of a polymer with a refractive index of 1.568. Because cladding 12 has a lower refractive index than core 11, light propagates along core 11, and because cladding 22 has a lower refractive index than core 21, light propagates along core 21.

[0019] The core 11 is covered by the cladding 12 to form a first optical waveguide 100 for propagating signal light along the core 11. The core 21 is covered by the cladding 22 to form a second optical waveguide 200 for propagating signal light along the core 21. The first component 10, the second component 20, the first optical waveguide 100, and the second optical waveguide 200 may be even longer in the Y-axis direction compared to the configuration in Figure 1.

[0020] Figure 2 is an internal perspective view of the optical connector 1 as seen in the negative X-axis direction. In Figure 2, diagonal lines are used to distinguish each component.

[0021] The first optical waveguide 100 formed in the first component 10 is located in close proximity to the upper surface of the first component 10 (the upper surface of the cladding 12). The second optical waveguide 200 formed in the second component 20 is located in close proximity to the lower surface of the second component 20 (the lower surface of the cladding 22).

[0022] The signal light is input to the first optical waveguide 100 from a device upstream of the optical connector 1 (for example, a laser element or optical fiber) at the Y-axis negative end face of the first component 10. The signal light is, for example, light with a wavelength of 1.31 μm. The signal light input to the first optical waveguide 100 propagates along the first optical waveguide 100 to the overlapping region R1 of the first component 10 and the second component 20, which is shown by the dashed line.

[0023] The signal light propagated along the first optical waveguide 100 to the overlapping region R1 is propagated to the second optical waveguide 200 of the second component 20 in the overlapping region R1. That is, the signal light is urged to propagate to the second optical waveguide 200 by its electromagnetic field acting on the second optical waveguide 200 (core 21) with a high refractive index. This effect is more likely to occur as the electromagnetic field acting on the second optical waveguide 200 (core 21) is higher. Thereafter, the signal light propagated to the second component 20 is propagated along the second optical waveguide 200 to the end face on the positive Y-axis side of the second component 20 and output to a subsequent device (for example, an optical fiber or the like).

[0024] FIGS. 3(a) to 3(c) are cross-sectional views when the optical connector 1 is cut at C21-C22, C31-C32, and C11-C12 in FIG. 2, respectively.

[0025] As shown in FIGS. 3(a) to 3(c), the cross-sections of the cores 11 and 21 are square, and the cross-sectional sizes of the cores 11 and 21 are equal to each other. As shown in FIG. 3(b), in the overlapping region R1, in the Z-axis direction, the core 11 of the first optical waveguide 100 and the core 21 of the second optical waveguide 200 are close to each other, and in the X-axis direction, the four cores 21 of the second optical waveguide 200 are close to each other. Thereby, in the overlapping region R1, the signal light of the first optical waveguide 100 propagates to the part where the above effect is most likely to occur among the four core 21 parts of the second optical waveguide 200.

[0026] FIG. 4 is a plan view showing the configuration when the optical connector 1 is viewed in the negative Z-axis direction.

[0027] In FIG. 4, for the sake of convenience, the first component 10 and the second component 20 are illustrated in a state separated in the Y-axis direction.

[0028] The first optical waveguide 100 has a straight portion 110 extending in the Y-axis direction in the overlapping region R1. The second optical waveguide 200 has four straight portions 210 extending in the Y-axis direction in the overlapping region R1, a single main waveguide portion 220 disposed on the downstream side in the propagation direction of the signal light, and a connection portion 230 connecting the four straight portions 210 and the main waveguide portion 220. The connection portion 230 has a branching portion 231 that branches the second optical waveguide 200 from the main waveguide portion 220 toward the straight portion

[0029] The signal light from the first optical waveguide 100 propagates from the straight portion 110 to any one of the four straight portions 210 in the overlapping region R1. The propagation of the signal light from the straight portion 110 to the straight portion 210 is caused by the electromagnetic field of the signal light propagating through the straight portion 110 acting on the straight portion 210 as described above. The signal light that has propagated to any one of the straight portions 210 travels in the positive Y-axis direction and then propagates to the main waveguide portion 220 through the branching portion 231. Each curved portion of the connection portion 230 is shaped such that the curvature in plan view is small. Thereby, the optical loss in the connection portion 230 can be suppressed.

[0030] Here, when a displacement occurs in the X-axis direction between the first component 10 and the second component 20, in FIG. 4, the straight portion 110 of the first optical waveguide 100 moves relatively in the X-axis direction with respect to the straight portion 210 of the second optical waveguide 200. At this time, in the case of a configuration (comparative example) in which only one straight portion 210 is provided at the central position in the X-axis direction, in the X-axis direction, the position of the straight portion 110 is shifted with respect to the position of the straight portion 210. For this reason, the electromagnetic field intensity of the signal light applied to the second optical waveguide 200 decreases, and the coupling between the first optical waveguide 100 and the second optical waveguide 200 decreases. As a result, it becomes difficult for the signal light to propagate to the second optical waveguide 200, and a so-called optical loss problem occurs.

[0031] In contrast, in the present embodiment, since four straight portions 210 are provided in the second optical waveguide 200, even if a displacement occurs between the first optical waveguide 100 and the second optical waveguide 200 in the X-axis direction, the straight portion 110 of the first optical waveguide 100 approaches any one of the four straight portions 210 of the second optical waveguide 200. Thereby, the signal light of the straight portion 110 propagates to any one of the four straight portions 210. Therefore, even if a displacement occurs in the X-axis direction, optical loss can be suppressed.

[0032] When a displacement occurs in the Y-axis direction between the first component 10 and the second component 20, the overlap in the Y-axis direction between the straight portion 110 and the straight portion 210 is maintained according to the lengths of the straight portion 110 and the straight portion 210 in the Y-axis direction. Therefore, almost no optical loss occurs even if a displacement occurs in the Y-axis direction.

[0033] <Effects of Embodiment 1> According to Embodiment 1, the following effects are achieved.

[0034] As shown in Figure 1, the optical connector 1 comprises a first component 10 and a second component 20 that overlap each other, and transmits signal light from the first optical waveguide 100 of the first component 10 to the second optical waveguide 200 of the second component 20 through the overlapping region R1 of the first component 10 and the second component 20. As shown in Figure 4, the first optical waveguide 100 has at least one straight section 110 that extends in the Y-axis direction (first direction) substantially perpendicular to the Z-axis direction (overlapping direction of the first component 10 and the second component 20) in at least the overlapping region R1. The second optical waveguide 200 includes a plurality of linear sections 210 aligned in the X-axis direction (a second direction perpendicular to the overlap direction and the first direction) in at least the overlapping region R1 and extending in the Y-axis direction (first direction), a single leading wave section 220 located downstream in the propagation direction of the signal light, and a connecting section 230 connecting the plurality of linear sections 210 and the leading wave section 220.

[0035] With this configuration, even if a misalignment occurs between the first component 10 and the second component 20, and a misalignment occurs between the first optical waveguide 100 and the second optical waveguide 200 in the X-axis direction, the straight portion 110 of the first optical waveguide 100 approaches one of the multiple straight portions 210 of the second optical waveguide 200, allowing signal light to propagate from the first optical waveguide 100 to the second optical waveguide 200. This suppresses optical loss due to misalignment in the X-axis direction. Furthermore, even if a misalignment occurs between the first optical waveguide 100 and the second optical waveguide 200 in the Y-axis direction, the overlap between the straight portion 110 of the first optical waveguide 100 and the straight portion 210 of the second optical waveguide 200 is maintained. As a result, optical loss due to misalignment in the Y-axis direction is substantially eliminated. Therefore, optical loss due to misalignment between the first optical waveguide 100 and the second optical waveguide 200 can be suppressed.

[0036] <Example of modification of Embodiment 1> In Embodiment 1, the connection portion 230 of the second optical waveguide 200 is provided with one branch portion 231, but it may be provided with multiple branch portions.

[0037] Figure 5 is a plan view showing the configuration of the optical connector 1 as viewed in the negative Z-axis direction in this modified example.

[0038] In this modified example, compared to Embodiment 1 shown in Figure 4, the connection section 230 of the second optical waveguide 200 includes one branching section 232 and two branching sections 233 that branch the optical waveguide in stages from the leading wave section 220 toward the straight section 210. Branching section 232 branches the leading wave section 220 into two, and branching section 233 branches the single optical waveguide branched by branching section 232 into two. The straight section 210 is connected to each optical waveguide branched by branching section 233.

[0039] In the overlapping region R1, the signal light propagating from the linear section 110 to the linear section 210 travels in the positive direction of the Y axis. The signal light from the linear section 210 propagates to the branching section 232 via the branching section 233, and the signal light from the branching section 233 propagates to the leading wave section 220 via the branching section 232.

[0040] <Effects of the modified example of Embodiment 1> According to this modified example, the following effects are achieved.

[0041] The connection section 230 has a plurality of branching sections 232, 233 that branch the optical waveguide in stages from the leading wave section 220 toward the straight section 210.

[0042] With this configuration, the signal light propagating to the linear section 210 is gradually focused toward the leading wave section 220, thus suppressing optical loss in the connection section 230. In other words, because the signal light is gradually focused from the linear section 210 toward the leading wave section 220, the width in the X-axis direction of the branching sections 232 and 233 can be made smaller than the width in the X-axis direction of the branching section 231 in the embodiment 1 shown in Figure 4. As a result, the shapes of the branching sections 232 and 233 can be formed smoothly, thus suppressing optical loss in the branching sections 232 and 233. Furthermore, in the configuration of Figure 4, the width in the X-axis direction of the branching section 231 is large, so in this width, not only the fundamental mode but also higher-order modes (modes of optical distribution with multiple peaks) are generated, and there is a risk of signal light loss occurring as the width narrows from the branching section 231 toward the leading wave section 220. In contrast, in this modified example, the width of the branching sections 232 and 233 in the X-axis direction is small, so higher-order modes are suppressed and optical loss due to the branching sections 232 and 233 can be suppressed.

[0043] Furthermore, by using multiple branching sections 232 and 233, the number of straight sections 210 can be smoothly increased while suppressing optical loss in the connection section 230 as described above. In the configuration of Figure 5, two stages of branching sections 232 and 233 are arranged, but by arranging even more stages of branching sections, the number of straight sections 210 can be increased while suppressing optical loss.

[0044] <Embodiment 2> In Embodiment 1, the sizes of the first optical waveguide 100 and the second optical waveguide 200 in the X-Z plane were constant. In contrast, in Embodiment 2, the sizes of the first optical waveguide 100 and the second optical waveguide 200 in the X-Z plane are set to be smaller in the overlapping region R1.

[0045] Figure 6 is a plan view showing the configuration of the optical connector 1 as viewed in the negative Z-axis direction according to this embodiment.

[0046] In this embodiment, the straight sections 110 and 210 are thinner compared to the modified example of Embodiment 1 shown in Figure 5.

[0047] In other words, the first optical waveguide 100 has a linear section 110 extending in the Y-axis direction in the overlapping region R1, and a single leading wave section 120 positioned upstream in the propagation direction of the signal light. The linear section 110 and the leading wave section 120 are connected to each other. The leading wave section 120 has the same thickness as the linear section 110 in the modified example of Embodiment 1, and the linear section 110 in this embodiment is thinner than the leading wave section 120. Similarly, the linear section 210 has the same thickness as the linear section 210 in the modified example of Embodiment 1, and the linear section 210 in this embodiment is thinner than the leading wave section 220.

[0048] Here, around the core 11 constituting the first optical waveguide 100, and around the core 21 constituting the second optical waveguide 200, coupling ranges R11 and R12 are formed, respectively, based on the action of the electromagnetic field of the signal light propagating through the cores 11 and 21, which can strongly promote the propagation of signal light between these waveguides.

[0049] In Figure 6, for convenience, only the coupling range R11 based on the straight section 110 of the coupling range R11 based on the first optical waveguide 100 is shown with a dashed line, and only the coupling range R12 of the straight section 210 of the coupling range R12 based on the second optical waveguide 200 is shown with a dashed line.

[0050] The coupling range is the range in which, in two adjacent optical waveguides, the ratio of power propagating from one optical waveguide to the other (coupling coefficient) is a predetermined ratio (for example, 80% or more). Therefore, when the linear section 210 is positioned within the coupling range R11 of the linear section 110, and the linear section 110 is positioned within the coupling range R12 of the linear section 210, the coupling coefficient of the linear section 110 and the linear section 210 becomes a predetermined ratio or greater, and signal light propagates from the linear section 110 to the linear section 210 with the desired coupling coefficient. The coupling ranges R11 and R12 will be explained in more detail later with reference to Figures 9(a) to 10(b).

[0051] In Embodiment 1, coupling ranges are formed for the first optical waveguide 100 and the second optical waveguide 200. However, the coupling range R11 of the linear section 110 in this embodiment is larger than the coupling range of the linear section 110 in Embodiment 1, and the coupling range R12 of the linear section 210 in this embodiment is larger than the coupling range of the linear section 210 in Embodiment 1.

[0052] In this embodiment, the coupling range R13 based on the four linear sections 210 is larger in the X-axis direction compared to Embodiment 1. Therefore, if a misalignment occurs in the X-axis direction between the first component 10 and the second component 20, the coupling range R11 is more likely to overlap with the coupling range R13. For this reason, optical loss can be further suppressed with respect to misalignment in the X-axis direction compared to Embodiment 1.

[0053] In this embodiment as well, if a misalignment occurs in the Y-axis direction between the first component 10 and the second component 20, the overlap in the Y-axis direction between the connectable range R11 and the connectable range R12 is maintained. Therefore, similar to Embodiment 1 and its modified examples, optical loss can be suppressed with respect to misalignment in the Y-axis direction.

[0054] Figure 7 is an internal perspective view of the optical connector 1 as seen in the negative X-axis direction according to this embodiment.

[0055] In this embodiment, compared to the modified example of Embodiment 1, the lower end of the core 11 in the overlapping region R1 is moved upward. As a result, the portion of the linear portion 110 that is away from the linear portion 210 is closer to the linear portion 210, and in the Z-axis direction, the thickness of the linear portion 110 is smaller than the thickness of the leading wave portion 120. Also, the upper end of the core 21 in the overlapping region R1 is moved downward. As a result, the portion of the linear portion 210 that is away from the linear portion 110 is closer to the linear portion 110, and in the Z-axis direction, the thickness of the linear portion 210 is smaller than the thickness of the leading wave portion 220 and the connecting portion 230.

[0056] Furthermore, the lower end of the leading wave portion 120 near the positive Y-axis end is smoothly displaced upward as it moves in the positive Y-axis direction. This suppresses optical loss in this portion. Similarly, the upper end of the connecting portion 230 near the negative Y-axis end is smoothly displaced downward as it moves in the negative Y-axis direction. This suppresses optical loss in this portion.

[0057] Figures 8(a) to 8(c) are cross-sectional views of the optical connector 1 according to this embodiment, when it is cut along C21-C22, C31-C32, and C11-C12 in Figure 7, respectively.

[0058] In this modified example as well, the cross-sections of cores 11 and 21 are square. As shown in Figures 8(a) and 8(c), the C21-C22 and C11-C12 cross-sections are the same as in Figures 3(a) and 8(c). As shown in Figure 8(b), in the C31-C32 cross-section, the size of cores 11 and 21 in the X-Z plane is smaller compared to Figure 3(b). In Figure 8(b), the cross-sectional sizes of cores 11 and 21 are equal to each other.

[0059] In this way, by reducing the cross-section of cores 11 and 21 in the overlapping region R1, the coupling ranges R11 and R12 in the overlapping region R1 can be made larger compared to the coupling ranges R11 and R12 outside the overlapping region R1. As a result, the coupling ranges R11 and R12 in the overlapping region R1 are more likely to overlap, so even if a misalignment occurs, signal light can be transmitted from the first optical waveguide 100 to the second optical waveguide 200.

[0060] Next, the preferred width in the X-axis direction of the first optical waveguide 100 and the second optical waveguide 200 will be described.

[0061] Figure 9(a) is a graph showing the relationship between the width of the optical waveguide in the X-axis direction and the FWHM (Full Width at Half Maximum) of the optical distribution. The calculation conditions are that the refractive indices of the core and cladding are 1.577 and 1.568, respectively, and the wavelength of the guided light is 1.31 μm. As shown in Figure 9(b), the FWHM of the optical distribution is the width of the optical distribution (electromagnetic field intensity distribution) when the light intensity is half of the peak.

[0062] As shown in the graph in Figure 9(a), when the width of the optical waveguide is reduced from 10 μm, the FWHM decreases as the waveguide width decreases, indicating that the spread of light propagating through the waveguide becomes narrower. This indicates that when the width of the optical waveguide is sufficiently large, light is confined according to the width. On the other hand, when the width of the optical waveguide is reduced from 2 μm, the FWHM increases as the waveguide width decreases, indicating that the spread of light propagating through the waveguide becomes wider. This indicates that light is not confined within the optical waveguide but spreads outside of it. In other words, by reducing the width of the optical waveguide in this way, the range over which light propagates through the optical waveguide can be expanded.

[0063] Figure 10(a) is a graph showing the relationship between the displacement (distance between centers) of two adjacent optical waveguides and the coupling coefficient. The same refractive index and wavelength values ​​as in Figure 9(a) are used.

[0064] Figure 10(a) shows the coupling coefficients when the widths of the two optical waveguides are the same, and when the widths of the optical waveguides are 0.5, 1, 2, 3, and 4 μm. When the misalignment is 0 μm, the two optical waveguides are aligned in the width direction. As shown in Figure 10(b), the coupling coefficient is the normalized overlap integral between the possible optical field intensity distributions in one optical waveguide and the possible optical field intensity distributions in the other optical waveguide. The coupling coefficient is C, and the electric field intensity distribution of one is E. １ (x), the other electric field strength distribution is E ２ If we denote it as (x), the coupling coefficient C is expressed as shown in equation (1) below.

[0065]

[0066] The coupling coefficient C is E １ (x) to E ２ (x) (or E ２ (x) to E １ This shows the proportion of power propagating to (x). When the coupling coefficient is 100%, it indicates that light propagates between the two optical waveguides without loss, and when the coupling coefficient is 0%, it indicates that no light propagates between the two optical waveguides at all. As shown in Figure 10(a), the smaller the width of the optical waveguide, the smaller the decrease in the coupling coefficient with respect to the amount of displacement. Therefore, it can be seen that the smaller the width of the optical waveguide, the more optical loss can be suppressed even if the two optical waveguides are shifted in the width direction.

[0067] As shown in Figure 9(a), by setting the width of the optical waveguide to 2 μm, the FWHM can be reduced to about 4 μm, and by setting the width of the optical waveguide to 0.5 μm, the FWHM of the optical waveguide can be increased to about 9 μm. Furthermore, as shown in Figure 10(a), when the width of the two optical waveguides is 0.5 μm, the coupling coefficient can be maintained at 80% or more even if the two optical waveguides are misaligned by about 3 μm. Here, the general allowable value for optical loss, 1 dB, corresponds to a coupling coefficient of about 80%. Therefore, by setting the width of each part in the X-axis direction as described later with reference to Figure 11, an optical connector 1 can be constructed that can suppress optical loss even when the positional misalignment in the X-axis direction is large.

[0068] The above-mentioned coupling ranges R11 and R12 can be defined as a range that is twice the amount of displacement when the coupling coefficient C is constant (for example, 80%). In the example in Figure 10(a), when the width of the straight sections 110 and 210 is 0.5 μm, the amount of displacement when the coupling coefficient is 80% is approximately 3 μm. Therefore, in this case, the coupling ranges R11 and R12 are approximately 6 μm.

[0069] Figure 11 is a plan view showing an example of the width in the X-axis direction of each part of the optical connector 1, based on the considerations in Figures 9(a) and 10(a).

[0070] The first optical waveguide 100 is preferably configured to confine light within the waveguide in order to avoid external influences (such as surface dust and scratches). Therefore, from the considerations in Figure 9(a), the width W12 of the leading wave portion 120 is set to 2 μm. For the same reason, the widths W22 of the leading wave portion 220 and the connecting portion 230 of the second optical waveguide 200 are also set to 2 μm. On the other hand, the straight sections 110 and 210 are preferably configured to broaden the width of the light distribution. Therefore, from the considerations in Figure 9(a), the widths W11 of the straight section 110 and W21 of the straight section 210 are set to 0.5 μm.

[0071] Furthermore, from the considerations in Figure 10(a), if the positional misalignment between the straight section 110 and one of the straight sections 210 is within the range of ±3 μm, the coupling coefficient between them can be maintained at 80% or more. Therefore, for each straight section 210, the allowable range W23 of misalignment between the straight section 110 and the straight section 210 is 3 μm × 2 = 6 μm. Thus, as long as the center of the straight section 110 is located within a 24 μm range W24, which is formed by arranging four 3 μm × 2 ranges corresponding to each straight section 210 in the X-axis direction, the coupling coefficient between the straight section 110 and any of the straight sections 210 can be maintained at 80% or more.

[0072] The preferred width in the X-axis direction of the first optical waveguide 100 and the second optical waveguide 200 has been described above, and the same applies to the preferred thickness in the Z-axis direction.

[0073] Figure 12 is a side view showing an example of the thickness in the Z-axis direction of each part of the optical connector 1, based on the considerations in Figures 9(a) and 10(a).

[0074] Similar to the case in Figure 11, the first optical waveguide 100 is preferably configured to confine light within the waveguide in order to avoid external influences (such as surface dust and scratches), so the thickness T12 of the leading wave portion 120 is set to 2 μm. For the same reason, the thickness T22 of the leading wave portion 220 and the connecting portion 230 of the second optical waveguide 200 is also set to 2 μm. On the other hand, the straight portions 110 and 210 are preferably configured to have a larger thickness of light distribution. Therefore, in Figure 9(a), the width is read as thickness, and the thickness T11 of the straight portion 110 and the thickness T21 of the straight portion 210 are set to 0.5 μm.

[0075] Furthermore, in order to avoid influences from the upper surface of the first component 10 (such as dust and scratches on the upper surface), it is preferable that the first optical waveguide 100 be located low above the upper surface. For the same reason, it is preferable that the second optical waveguide 200 be located high above the lower surface. Also, in the Z-axis direction, it is preferable that the coupling coefficient between the straight section 110 and the straight section 210 be 80% or more. Therefore, the distance D1 between the upper end of the first optical waveguide 100 and the upper surface of the first component 10 is set to 1.25 μm, the distance D2 between the lower end of the second optical waveguide 200 and the lower surface of the second component 20 is set to 1.25 μm, and the distance D3 between the centers of the straight section 110 and the straight section 210 is set to 3 μm.

[0076] Furthermore, a step 100a is formed near the positive Y-axis end of the leading wave portion 120, causing the lower end of the leading wave portion 120 to smoothly displace upward, and a step 200a is formed near the negative Y-axis end of the connecting portion 230, causing the upper end of the connecting portion 230 to smoothly displace downward. By increasing the radius of curvature of the steps 100a and 200a to a certain extent, optical loss of signal light can be suppressed at the steps 100a and 200a.

[0077] Furthermore, when setting the size of each part as shown in Figures 11 and 12, the length of the straight sections 110 and 210 in the Y-axis direction is set to, for example, 5 mm to 30 mm, preferably 6 mm. This ensures that even if the first part 10 and the second part 20 are shifted to some extent in the Y-axis direction, the overlap between the straight sections 110 and 210 in the Y-axis direction can be maintained.

[0078] <Effects of Embodiment 2> According to Embodiment 2, the following effects are achieved.

[0079] As shown in Figure 6, in the X-axis direction (second direction), the width of the straight section 210 is narrower than the width of the leading wave section 220.

[0080] This configuration widens the range R12 in which each linear section 210 can be coupled in the X-axis direction. As a result, even if a large misalignment occurs in the X-axis direction, it becomes easier to propagate the signal light from the linear section 110 to the linear section 210, and optical loss can be suppressed more effectively.

[0081] As shown in Figure 6, the first optical waveguide 100 has a single leading wave section 120 positioned upstream of at least one linear section 110 in the direction of signal light propagation and connected to at least one linear section 110. In the X-axis direction (second direction), the width of the linear section 110 is narrower than the width of the leading wave section 120.

[0082] With this configuration, the width of the connectable range R11 of the linear section 110 in the X-axis direction becomes wider, so the connectable range R11 of the linear section 110 is more likely to overlap with the connectable range R13 based on the multiple linear sections 210 in the X-axis direction. Therefore, even if a large positional misalignment occurs in the X-axis direction, it becomes easier to propagate light from the linear section 110 to the linear section 210, and optical loss can be suppressed more effectively.

[0083] As shown in Figure 7, the thickness of the second optical waveguide 200 is changed such that the upper surface of the straight section 210 is closer to the lower surface of the second component 20 than the upper surface of the leading wave section 220.

[0084] This configuration allows for an increase in the thickness of the coupling range R12 of the linear section 210 in the Z-axis direction without increasing the distance between the linear section 110 and the linear section 210. This enables efficient propagation of signal light from the linear section 110 to the linear section 210.

[0085] As shown in Figure 7, the thickness of the first optical waveguide 100 is changed such that the lower surface of the straight section 110 is closer to the upper surface of the first component 10 than the lower surface of the leading wave section 120.

[0086] According to this configuration, without increasing the distance between the straight portion 110 and the straight portion 210, the thickness of the connectable range R11 of the straight portion 110 in the Z-axis direction can be increased. Thereby, the signal light from the straight portion 110 can be efficiently propagated to the straight portion 210.

[0087] <Design method of the first optical waveguide and the second optical waveguide> The design method of the first optical waveguide 100 and the second optical waveguide 200 will be described.

[0088] In the following description, the signal light to be propagated is in the fundamental transverse mode. In the above formula (1), for the electric field strength distributions E １ (x), E ２ (x), if the centers are set to x = −z and x = z, respectively, then E １ (x), E ２ (x) can be expressed by the following formulas (2) and (3).

[0089]

[0090] Here, E in the above formulas (2) and (3) ｐ , E ｍ , E’ are expressed by the following formula (4).

[0091]

[0092] The symbols used in the above formulas (2) to (4) are as shown in the following table.

[0093]

[0094] In the above formula (1), if only the electric field amplitude is considered, the absolute value can be removed. Thereby, the above formula (1) becomes the following formula (5).

[0095]

[0096] By transforming the above formula (5) and substituting the above formulas (2) to (4), the following formula (6) is obtained.

[0097]

[0098] Here, if we let θ (0 ≤ θ ≤ 1) be the coupling coefficient that the design must satisfy (the value required by the system), then the amount of deviation in this design method must satisfy the following equation (7).

[0099] θ ≤ C …(7)

[0100] The maximum allowable deviation that satisfies the above formula (7) is z ｍａｘ Let z in equation (6) above be z ｍａｘ After making the substitution, substituting the coupling coefficient C in equation (6) above into equation (7) above yields the following equation (8): Maximum allowable displacement z ｍａｘ This is the solution to equation (8) below.

[0101] Ae ｘ = Bx + C …(8)

[0102] In equation (8) above, x, A, B, and C are expressed by the following equations (9) and (10).

[0103]

[0104] When x is small (the amount of displacement between the two optical waveguides is small), e ｘ The quadratic Taylor expansion (1 + x + x ２ If it can be approximated by / 2), that is, if half the difference between the two optical waveguides is less than 5 μm, then the maximum allowable difference z ｍａｘ This can be expressed as an analytical solution in the following equation (11).

[0105]

[0106] The maximum allowable deviation z obtained in this way ｍａｘ According to this, the straight section 110 and one straight section 210 are 2z ｍａｘ Even if the offset is only by a small amount, these coupling coefficients will be greater than or equal to θ. Therefore, the distance (pitch) between the centers in the X-axis direction of two adjacent straight sections 210 is 2 × 2z ｍａｘ = 4z ｍａｘ Therefore, as shown in Figure 13, each of the n straight sections 210 of the second optical waveguide 200 is connected to one straight section 110 of the first optical waveguide 100 by 4z. ｍａｘA coupling coefficient of θ or greater can be achieved for the amount of misalignment. Also, if S is the width in the X-axis direction that is allowed for the formation of the second optical waveguide 200, then the number n of the straight sections 210 is S / (4z). ｍａｘ )

[0107] According to the above design method, the refractive index n of the cores 11 and 21 ２ , the refractive index n of cladding 12, 22 １ If the width 2w of the straight sections 110 and 210, and the required coupling coefficient θ are entered as conditions, then n will be calculated based on the table above. ｅｆｆ κ １ κ ２ Calculate and calculate A, B, and C based on the above formula (10), find the solution x based on the above formula (8), and z based on the above formula (9). ｍａｘ This calculates the pitch between two adjacent straight sections 210, which is 4z. ｍａｘ Output the following, and as the number of straight sections 210 n, S / (4z) ｍａｘ It can output ).

[0108] Furthermore, in the above design method, the maximum allowable displacement z ｍａｘ This was calculated by analysis, but it is not limited to this method; it may also be calculated by numerically integrating the above equation (1).

[0109] Next, referring to Figure 14, the possible values ​​for the width, pitch, and number of the straight sections 210 of the second optical waveguide 200 in the X-axis direction will be explained.

[0110] Figure 14 is a graph showing the relationship between the width, displacement, and maximum number of optical waveguides.

[0111] The dotted lines in Figure 14 show the displacement amounts for optical waveguide widths of 0.5 μm, 1 μm, 2 μm, 3 μm, and 4 μm, when the coupling coefficient is set to 80% in the graph of Figure 10(a). The thin solid lines in Figure 14 show the displacement amount, which is twice the displacement amount shown by the dotted lines in Figure 14, as the maximum pitch of two adjacent optical waveguides. The thick solid lines in Figure 14 show the maximum number of optical waveguides for the maximum pitch shown by the thin solid lines in Figure 14 when multiple optical waveguides are arranged side by side. The maximum number is the value obtained by dividing the width S allowed for the formation of multiple optical waveguides by the maximum pitch. Here, the width S is set to 125 μm, which is the standard outer diameter of an optical fiber.

[0112] For two adjacent linear sections 210 to not overlap, the amount of displacement when their coupling coefficient is 80% must be greater than the width of the linear section 210. That is, in the dotted graph of Figure 14, the value on the left vertical axis must be greater than the value on the horizontal axis. Therefore, the optical waveguide width (the width of the linear section 210 in the X-axis direction) must be 1.5 μm or less.

[0113] Therefore, when the optical waveguide width (width of the straight section 210 in the X-axis direction) is 1.5 μm or less, according to the thin solid line graph in Figure 14, the maximum pitch (distance between the centers of two adjacent straight sections 210 in the X-axis direction) can be 7 μm or less, and according to the thick solid line graph in Figure 14, the maximum number (number of straight sections 210 aligned in the X-axis direction) can be 50 or less.

[0114] <Embodiment 3> In Embodiments 1 and 2, the first optical waveguide 100 had one straight section 110, but it is not limited to this, and like the second optical waveguide 200 in Embodiments 1 and 2, it may have a branching structure and have multiple straight sections 110.

[0115] Figure 15 is a plan view showing the configuration of the optical connector 1 as viewed in the negative Z-axis direction according to this embodiment.

[0116] In this embodiment, the first component 10 is configured similarly to the second component 20, compared to Embodiment 2 shown in Figure 6. Furthermore, the first component 10 and the second component 20 are superimposed on each other in the overlapping region R1, similar to Embodiment 2 shown in Figure 7.

[0117] The first optical waveguide 100 includes four linear sections 110 aligned in the X-axis direction, a single leading wave section 120 positioned upstream in the propagation direction of the signal light, and a connecting section 130 that connects the four linear sections 110 and the leading wave section 120.

[0118] The connection section 130 has one branching section 131 and two branching sections 132 that branch the waveguide in stages from the leading wave section 120 toward the straight section 110. Branching section 131 branches the leading wave section 120 into two, and branching section 132 branches the single optical waveguide branched by branching section 131 into two. The straight section 110 is connected to each optical waveguide branched by branching section 132.

[0119] The signal light input to the leading wave section 120 is divided at the branching section 131, and the two divided signal lights propagate to the two branching sections 132, respectively. The signal light propagated to the branching sections 132 is further divided at the branching section 132, and the two divided signal lights propagate to the two linear sections 110, respectively. In this way, the signal light input to the leading wave section 120 is divided into four parts and propagates almost equally to the four linear sections 110. Meanwhile, in the overlapping region R1, the signal lights from the four linear sections 110 propagate to the four linear sections 210, respectively. Subsequently, the signal lights from the four linear sections 210 are combined via branching sections 233 and 232 and output from the leading wave section 220.

[0120] In this embodiment, the first optical waveguide 100 and the second optical waveguide 200 are configured such that, regardless of which path the signal light takes through the first optical waveguide 100 and the second optical waveguide 200, the optical path length of each path, i.e., the actual path length divided by the refractive index of the cores 11 and 21, is equal to each other. This makes it possible to suppress the difference in arrival time of the signal light for each path downstream of the optical connector 1.

[0121] As shown in Figure 15, when the first optical waveguide 100 is configured in a comb shape and a plurality of straight sections 110 are provided, optical loss can be suppressed even if dirt, foreign matter, scratches, etc. are present on the surface of the first component 10.

[0122] For example, let's consider the case where a scratch occurs on the upper surface of one of the straight sections 110. In Figure 15, for convenience, an "X" mark indicating a scratch on the upper surface of the straight section 110 is superimposed on the straight section 110. When a scratch occurs in one straight section 110 in this way, signal light from the other three straight sections 110 propagates to the second optical waveguide 200. In this case, 75% of the signal light input to the first optical waveguide 100 propagates to the second optical waveguide 200 and is output from the second optical waveguide 200. In this way, although some signal light is lost, 75% of the signal light can be propagated, so the optical loss can be kept to approximately 1 dB or less.

[0123] <Effects of Embodiment 3> According to Embodiment 3, the following effects are achieved.

[0124] The first optical waveguide 100 has a plurality of linear sections 110 arranged in the X-axis direction (second direction), a single leading wave section 120 positioned upstream in the propagation direction of the signal light, and a connecting section 130 that connects the plurality of linear sections 110 and the leading wave section 120.

[0125] With this configuration, even if a defect occurs in one of the multiple linear sections 110, such as dirt, foreign matter, or scratches on the upper surface of the first component 10 corresponding to the linear section 110, the signal light from the other linear sections 110 can still be propagated to the linear section 210. Therefore, even if a defect occurs in one of the multiple linear sections 110, the loss of all signal light can be avoided, and optical loss can be minimized.

[0126] The connection section 130 has a plurality of branching sections 131 and 132 that branch the waveguide in stages from the leading wave section 120 toward the straight section 110.

[0127] With this configuration, the signal light input to the leading wave section 120 is spectrally separated in steps from the leading wave section 120 toward the linear section 110, thereby suppressing optical loss in the connection section 130. In other words, because the signal is spectrally separated in steps from the leading wave section 120 toward the linear section 110, the width of the branching sections 131 and 132 in the X-axis direction can be reduced. As a result, the shape of the branching sections 131 and 132 can be formed smoothly, thereby suppressing optical loss in the branching sections 131 and 132. In addition, because the width of the branching sections 131 and 132 in the X-axis direction is small, higher-order modes are suppressed, and optical loss due to the branching sections 132 and 132 can be suppressed.

[0128] Furthermore, with multiple branching sections 131 and 132, the number of straight sections 110 can be smoothly increased while suppressing optical loss in the connection section 130 as described above.

[0129] <Example of modification of Embodiment 3> In Embodiment 3, four straight sections 110 were provided as an example of a case where multiple straight sections 110 are provided. However, the number of straight sections 110 is not limited to four, as long as it is less than or equal to the number of straight sections 210.

[0130] Figure 16 is a plan view showing the configuration of the optical connector 1 as viewed in the negative Z-axis direction according to this modification example.

[0131] In this modified example, compared to Embodiment 3 shown in Figure 15, there are two linear sections 110. The connection section 130 includes one branch section 133. In this case, even if a malfunction occurs in either linear section 110, 50% of the signal light is propagated from the first optical waveguide 100 to the second optical waveguide 200 by the other linear section 110. Therefore, even if a malfunction occurs in either of the two linear sections 110, the loss of all signal light can be avoided.

[0132] Furthermore, the combination of the number of straight sections 110 and straight sections 210 is not limited to the above embodiment and modified examples, as long as the number of straight sections 110 is less than or equal to the number of straight sections 210. For example, four straight sections 110 may be provided and eight straight sections 210 may be provided.

[0133] <Other Modification Examples> In the above embodiment and modification examples, the cores 11 and 21 were square in cross-section parallel to the X-Z plane, but the cores 11 and 21 may have shapes other than square. For example, the cores 11 and 21 may be rectangular, polygonal, circular, or elliptical.

[0134] In the above embodiments and modifications, the leading wave portions 120 and 220 are formed parallel to the Y-axis direction, but are not limited to this; they may be curved or meandering with respect to the Y-axis direction. For example, the leading wave portions 120 and 220 may have an arc shape in plan view.

[0135] In the above embodiments and modifications, the cladding 12 is formed over the entire first component 10. However, the invention is not limited to this, and the cladding 12 may be formed only around the core 11 in the region of the first component 10 excluding the overlapping region R1. Similarly, the cladding 22 is formed over the entire second component 20. However, the invention is not limited to this, and the cladding 22 may be formed only around the core 21 in the region of the second component 20 excluding the overlapping region R1.

[0136] In the above embodiments and modifications, the straight section 110 is formed parallel to the Y-axis direction, but it is not limited to this, and the lower end of the straight section 110 may be further displaced upward in steps as it progresses in the positive Y-axis direction. Similarly, the straight section 210 is formed parallel to the Y-axis direction, but it is not limited to this, and the upper end of the straight section 210 may be further displaced downward in steps as it progresses in the negative Y-axis direction.

[0137] In the above embodiments and modifications, a configuration to prevent reflection (for example, an AR coating) may be provided on the Y-axis positive end face of the first component 10 so that the signal light propagating along the linear portion 110 in the positive Y-axis direction is not reflected by the Y-axis positive end face of the first component 10. Similarly, a configuration to prevent reflection (for example, an AR coating) may be provided on the Y-axis negative end face of the second component 20.

[0138] In the above embodiments and modifications, the straight sections 110 and 210 are formed parallel to the Y-axis direction. However, the invention is not limited to this, and the straight sections 110 and 210 only need to be formed substantially parallel to the Y-axis direction. For example, they may be formed slightly inclined with respect to the Y-axis direction.

[0139] In the above embodiments and modifications, the widths of the linear sections 110 and 210 are set to be equal in the X-axis direction, but the invention is not limited to this, and they may be different. Similarly, in the Z-axis direction, the thicknesses of the linear sections 110 and 210 are set to be equal, but the invention is not limited to this, and they may be different.

[0140] In the above embodiment and its modifications, the first component 10 is installed on the lower surface of the second component 20, but it may also be installed on the upper surface of the second component 20. That is, the optical connector 1 in the above embodiment and its modifications may be arranged inverted in the Z-axis direction. Furthermore, substrates such as glass may be installed on the first component 10 and the second component 20, respectively.

[0141] Furthermore, the configuration of the optical connector 1, including the first component 10, the second component 20, the first optical waveguide 100, and the second optical waveguide 200, is not limited to the configuration shown in the above embodiment and modified examples, and can be changed as appropriate.

[0142] 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.

[0143] (Note) The above description of embodiments discloses the following technologies.

[0144] (Technical 1) An optical connector comprising a first component and a second component that overlap each other, for propagating signal light from a first optical waveguide of the first component to a second optical waveguide of the second component via an overlapping region of the first component and the second component, wherein the first optical waveguide has at least one sending-side linear portion extending in a first direction substantially perpendicular to the overlapping direction of the first component and the second component in at least the overlapping region, and the second optical waveguide has a plurality of receiving-side linear portions extending in a first direction, aligned in a second direction perpendicular to the overlapping direction and the first direction in at least the overlapping region, a single receiving-side leading-wave portion located downstream in the propagation direction of the signal light, and a receiving-side connecting portion connecting the plurality of receiving-side linear portions and the receiving-side leading-wave portion.

[0145] According to this technology, even if a misalignment occurs between the first and second components, and between the first and second optical waveguides in the second direction, the transmitting linear section approaches one of the multiple receiving linear sections, allowing the signal light to propagate from the first optical waveguide to the second optical waveguide. This suppresses optical loss due to misalignment in the second direction. Furthermore, even if a misalignment occurs between the first and second optical waveguides in the first direction, the overlap between the transmitting linear section and the receiving linear section is maintained. As a result, optical loss due to misalignment in the first direction is virtually eliminated. Therefore, optical loss due to misalignment between the first and second optical waveguides can be suppressed.

[0146] (Technology 2) An optical connector as described in Technology 1, characterized in that, in the second direction, the width of the receiving linear portion is narrower than the width of the receiving leading wave portion.

[0147] This technology widens the range of possible connections between each receiving linear section in the second direction. As a result, even if a large positional misalignment occurs in the second direction, it becomes easier to propagate the signal light from the sending linear section to the receiving linear section, thereby more effectively suppressing optical loss.

[0148] (Technology 3) An optical connector according to Technology 1 or 2, wherein the first optical waveguide is arranged upstream of at least one of the sending-side linear sections in the propagation direction of the signal light and has a single sending-side leading wave section connected to at least one of the sending-side linear sections, and in the second direction, the width of the sending-side linear section is narrower than the width of the sending-side leading wave section.

[0149] This technology widens the range of possible connections between the sending linear section and the receiving linear section in the second direction. As a result, the range of possible connections between the sending linear section and the possible connections based on multiple receiving linear sections in the second direction becomes more likely to overlap. Therefore, even if a large positional misalignment occurs in the second direction, it becomes easier to propagate light from the sending linear section to the receiving linear section, and optical loss can be suppressed more effectively.

[0150] (Technology 4) An optical connector according to any one of Technology 1 to 3, characterized in that the thickness of the second optical waveguide is changed such that the surface of the receiving side linear portion opposite to the first component is closer to the first component than the receiving side leading wave portion.

[0151] This technology allows for increasing the thickness of the connectable range of the receiving linear section in the overlapping direction without increasing the distance between the sending and receiving linear sections. This enables efficient propagation of signal light from the sending linear section to the receiving linear section.

[0152] (Technical 5) An optical connector according to any one of Technical 1 to 4, characterized in that the thickness of the first optical waveguide is changed such that the surface of the feed-side linear portion opposite to the second component is closer to the second component than the feed-side leading wave portion.

[0153] This technology allows for an increase in the thickness of the connectable range of the sending linear section in the overlapping direction without increasing the distance between the sending linear section and the receiving linear section. This enables efficient propagation of signal light from the sending linear section to the receiving linear section.

[0154] (Technology 6) An optical connector according to any one of Technology 1 to 5, characterized in that the receiving connection portion has a plurality of branching portions that branch the optical waveguide in stages from the receiving leading wave portion toward the receiving straight portion.

[0155] According to this technology, the signal light propagating to the receiving linear section is gradually focused toward the receiving leading wave section, thereby suppressing optical loss at the receiving connection section. Furthermore, by using multiple branching sections, the number of receiving linear sections can be smoothly increased while suppressing optical loss at the receiving connection section.

[0156] (Technical 7) An optical connector according to any one of Technical 1 to 6, wherein the first optical waveguide has a plurality of sending-side linear sections arranged in the second direction, a single sending-side leading wave section arranged on the upstream side in the propagation direction of the signal light, and a sending-side connecting section that connects the plurality of sending-side linear sections and the sending-side leading wave section.

[0157] According to this technology, even if a malfunction occurs in one of the multiple feeder linear sections, such as dirt, foreign matter, or scratches on the upper surface of the first component corresponding to the feeder linear section, the signal light from the other feeder linear sections can still be propagated to the receiving linear section. Therefore, even if a malfunction occurs in one of the multiple feeder linear sections, the loss of all signal light can be avoided, and optical loss can be minimized.

[0158] (Technical 8) An optical connector as described in Technical 7, characterized in that the sending-side connection portion has a plurality of branching portions that branch the waveguide in stages from the sending-side leading wave portion toward the sending-side straight portion.

[0159] According to this technology, the signal light input to the sending-side leading wave section is spectrally separated in steps from the sending-side leading wave section toward the sending-side linear section, thereby suppressing optical loss at the sending-side connection section.

[0160] 1 Optical connector 10 First component 20 Second component 100 First optical waveguide 110 Straight section (sender side straight section) 120 Leading wave section (sender side leading wave section) 130 Connection section (sender side connection section) 131, 132 Branch section 200 Second optical waveguide 210 Straight section (receiving side straight section) 220 Leading wave section (receiving side leading wave section) 230 Connection section (receiving side connection section) 232, 233 Branch section R1 Overlap region

Claims

1. An optical connector comprising a first component and a second component that overlap each other, for propagating signal light from a first optical waveguide of the first component to a second optical waveguide of the second component via an overlapping region of the first component and the second component, wherein the first optical waveguide has at least one sending-side linear section extending in a first direction substantially perpendicular to the overlapping direction of the first component and the second component in at least the overlapping region, and the second optical waveguide has a plurality of receiving-side linear sections aligned in a second direction perpendicular to the overlapping direction and the first direction in at least the overlapping region and extending in the first direction, a single receiving-side leading wave section located downstream in the propagation direction of the signal light, and a receiving-side connecting section connecting the plurality of receiving-side linear sections and the receiving-side leading wave section.

2. An optical connector according to claim 1, characterized in that, in the second direction, the width of the receiving linear portion is narrower than the width of the receiving leading wave portion.

3. An optical connector according to claim 1, wherein the first optical waveguide is arranged upstream of at least one of the sending-side linear sections in the propagation direction of the signal light and has a single sending-side leading wave section connected to at least one of the sending-side linear sections, and in the second direction, the width of the sending-side linear section is narrower than the width of the sending-side leading wave section.

4. An optical connector according to claim 1, characterized in that the thickness of the second optical waveguide is changed such that the surface of the receiving linear portion opposite to the first component is closer to the first component than the receiving leading wave portion.

5. An optical connector according to claim 1, characterized in that the thickness of the first optical waveguide is changed such that the surface of the feed-side linear portion opposite to the second component is closer to the second component than the feed-side leading wave portion.

6. An optical connector according to claim 1, characterized in that the receiving connection portion has a plurality of branching portions that branch the optical waveguide in stages from the receiving leading wave portion toward the receiving straight portion.

7. An optical connector according to any one of claims 1 to 6, wherein the first optical waveguide comprises a plurality of the sending-side linear sections arranged in the second direction, a single sending-side leading wave section located upstream in the propagation direction of the signal light, and a sending-side connecting section connecting the plurality of sending-side linear sections and the sending-side leading wave section.

8. An optical connector according to claim 7, characterized in that the sending-side connection portion has a plurality of branching portions that branch the waveguide in stages from the sending-side leading wave portion toward the sending-side straight portion.

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