Optical device and method for positioning optical device

Abstract

This optical device (10) configured to be optically connected to a connection target (200) comprises: at least one optical fiber (30); a substrate (20) provided with at least one first groove (21) in which each of the at least one optical fiber (30) is disposed; and a fixing member (50) for fixing the optical fiber (30) to the substrate (20). The substrate (10) further comprises at least one second groove (22) in which no optical fiber is disposed. The groove (22) is open to the same surface as the surface to which the groove (21) of the substrate (20) is open, and has a cross section parallel to the groove (21) and with the same shape as the cross section of the groove (21).

Description

Optical device and method for positioning optical device

[0001] The present invention relates to an optical device and a method for positioning an optical device.

[0002] Optical devices using optical fibers, such as optical fiber arrays that are optically connected to connection targets such as optical chips, are known (see Patent Document 1). When optically connecting an optical device to a connection target, alignment is performed. Alignment refers to the process of moving the optical device and the connection target relative to each other to align the optical waveguides (cores of optical fibers) of the optical device with the optical waveguides of the connection target, thereby efficiently coupling light propagating through each optical waveguide. Prior to the alignment, the optical device is positioned relative to the connection target so that the optical waveguides of the optical device and the connection target are as close as possible to each other.

[0003] Japanese Patent Application Publication No. 10-246838

[0004] One possible positioning method involves photographing an optical device, identifying the position of the optical fiber based on the photographed image, and then positioning the optical fiber based on the identified position. The inventors of the present application have devised a method for identifying the outline of a component, such as a substrate or lid, of an optical device using image processing, and then using the identified outline to identify the position of the optical fiber based on dimensional data of the optical device. However, because the dimensions of the component's outline do not require high accuracy, the positional accuracy of the reference outline is poor. Therefore, it was found that this method does not achieve high accuracy in positioning the optical device. Poor positioning accuracy, for example, can result in a large relative movement between the optical device and the connection target during subsequent alignment, specifically active alignment, which can result in a long alignment time.

[0005] An object of the present invention is to improve the positioning accuracy of an optical device.

[0006] In order to solve the above problem, the optical device of the present invention is an optical device configured to be optically connected to a connection object, and comprises: a substrate having at least one optical fiber and at least one first groove in which the at least one optical fiber is respectively arranged; and a fixing member for fixing the optical fiber to the substrate, wherein the substrate further comprises at least one second groove in which no optical fiber is arranged.

[0007] The positioning method for an optical device according to the present invention is a method for positioning the above-mentioned optical device relative to a connection object to which the optical device is optically connected, and comprises an imaging step of photographing the optical device and the connection object, and a positioning step of identifying the position of the second groove based on the image captured in the imaging step, and positioning the optical device based on the identified position of the second groove.

[0008] According to the present invention, the positioning accuracy of the optical device can be improved.

[0009] FIG. 1 is a perspective view of an optical device according to an embodiment of the present invention. FIG. 2 is an end view of the optical device of FIG. 1 as seen from the front. FIG. 3 is a configuration diagram of a system for positioning the optical device of FIG. 1. FIG. 4 is a flowchart of the positioning process performed by the processing unit of FIG. 3. FIG. 5 is an end view of an optical device according to a modified example as seen from the front. FIG. 6 is an end view of an optical device according to a modified example as seen from the front. FIG. 7 is an end view of an optical device according to a modified example as seen from the front. FIG. 8 is an end view of an optical device according to a modified example as seen from the front. FIG. 9 is a plan view of a combination of a substrate and an optical fiber of an optical device according to a modified example as seen from above.

[0010] Hereinafter, an embodiment of the present invention and its modifications will be described with reference to the drawings.

[0011] 1 and 2 is configured as an optical fiber array and includes a substrate 20, a plurality of optical fibers 30, a fixing member 40, and an adhesive layer 50. In the following description, the thickness direction of the substrate 20 is referred to as the up-down direction, and directions perpendicular to the up-down direction and perpendicular to each other are referred to as the front-rear direction and the left-right direction. These directions are used for convenience, and for example, the up-down direction does not have to coincide with the top-bottom direction.

[0012] The optical device 10 is configured to be optically connected to a connection target 200 such as an optical chip (e.g., a silicon photonics chip or a silica-based optical planar circuit). The connection target 200 is formed with a plurality of optical waveguides 210 that are optically coupled one-to-one with the optical fibers 30 of the optical device 10. A unit consisting of the optical device 10 and the connection target 200 is configured as an optical interconnect used in various optical communications including short- to medium-distance transmissions, for example, within a data center.

[0013] The substrate 20 is made of a transparent glass substrate or the like. The substrate 20 has a plurality of parallel grooves 21 in which a plurality of optical fibers 30 are respectively arranged, thereby positioning the plurality of optical fibers 30. At least a portion of the optical fibers 30 is inserted into the grooves 21, and the optical fibers 30 are supported by the inner surface of the grooves 21 and are positioned so as not to shift, particularly in the left-right direction. The substrate 20 also has empty grooves 22 in which no optical fibers are arranged, i.e., into which no optical fibers are inserted. The provision of these grooves 22 is a feature of this embodiment. Grooves 21 are also provided in conventional substrates.

[0014] Grooves 21 and 22 both open to the upper surface of substrate 20. Grooves 21 and 22 are spaced apart in the left-right direction and extend in the front-rear direction. Grooves 21 and 22 are V-grooves with a V-shaped cross section. Note that the cross section refers to a cross section cut along a plane in the up-down and left-right directions (the same applies hereinafter to cross sections).

[0015] Grooves 21 and 22 have the same cross-sectional shape and are parallel to each other. Therefore, groove 22 can be formed together with conventionally formed groove 21 using the same forming method as groove 21. For example, grooves 21 and 22 are formed one by one using the same V-shaped dicing blade. The dicing conditions (groove depth, blade feed speed, etc.) are also the same for each groove. Furthermore, multiple grooves of grooves 21 and 22 may be formed simultaneously using a single tool with multiple cutting portions. Because grooves 21 and 22 have the same cross-sectional shape and are parallel to each other, tool replacement and rotation of substrate 20 are not required when forming groove 22, which suppresses the resulting decrease in positional accuracy.

[0016] Since the positional accuracy when forming groove 21 has been good in the past, groove 22, which can be formed in the same manner as groove 21, can also be formed with high positional accuracy. Therefore, high accuracy can be obtained for the relative position of groove 22 with respect to groove 21. In this embodiment, the positioning of optical device 10 before alignment is performed based on the position of groove 22, so the high positional accuracy of groove 22 is useful for accurate positioning.

[0017] The groove 22 does not have to be newly formed. Specifically, one of the grooves 21 in the substrate 20 formed by a conventional method may be used as the groove 22 by not placing the optical fiber 30 in the groove 21.

[0018] The fixing member 40 is fixed to the substrate 20 with the optical fiber 30 sandwiched therebetween, thereby fixing the optical fiber 30 to the substrate 20. The fixing member 40 is made of a transparent glass substrate or the like. The fixing member 40 is fixed by an adhesive layer 50. For example, an adhesive is applied to each optical fiber 30 while it is placed in each groove 21 of the substrate 20. The fixing member 40 is then placed on the adhesive and pressed toward the substrate 20. This pressure causes the fixing member 40 to press the optical fiber 30 against the substrate 20, specifically against the inner surface of the groove 21. When the adhesive is cured in this state, the cured adhesive becomes an adhesive layer 50. The adhesive layer 50 is formed in a state where it fills the space between the substrate 20 and the fixing member 40, and fixes the optical fiber 30 and the fixing member 40 to the substrate 20. The adhesive layer 50 is formed in a shape that penetrates between the inner surface of the groove 21 and the optical fiber 30, and also into the groove 22. The adhesive layer 50 is made of, for example, a transparent resin. The fixing member 40 is also called a lid that covers the optical fiber 30.

[0019] Next, a method for positioning the optical device 10 relative to the connection target 200 will be described. The positioning method is executed, for example, by a system 100 shown in Fig. 3. The system 100 includes a moving mechanism 110, a camera 121, a camera 122, a light source 131, a photodetector 132, a dispenser 140, and a processing unit 150.

[0020] The movement mechanism 110 is configured to move the optical device 10 relative to the connection target 200. Moving the optical device 10 relative to the connection target 200 is a concept that includes moving only the optical device 10, moving only the connection target 200, and moving both. The movement mechanism 110 is, for example, a six-axis robot that moves and rotates the optical device 10 or the connection target 200 about three axes: up / down, left / right, and front / rear, and three rotational axes using the up / down, left / right, and front / rear axes as rotation axes. The movement mechanism 110 may be, for example, composed of a first movement device that moves the optical device 10 about two axes: up / down, left / right, and rotates it about two axes: up / down and left / right, and a second movement device that moves the connection target 200 about one axis: front / rear, and rotates it about one axis: front / rear. The movement of the optical device 10 and the movement of the connection target 200 are performed, for example, by moving a stage to which the optical device 10 or the connection target 200 is fixed.

[0021] The camera 121 is disposed at a position where it can photograph the optical device 10 and the connection target 200 from above. The camera 122 is disposed at a position where it can photograph the optical device 10 and the connection target 200 from below.

[0022] The light source 131 is configured to emit light to the optical waveguide 210. When the optical waveguide 210 of the connection target 200 and the optical fiber 30 of the optical device 10 are aligned, the light passes through them and is emitted from the optical fiber 30. The photodetector 132 receives the light emitted from the optical fiber 30. Note that the positions of the light source 131 and the photodetector 132 may be reversed.

[0023] The dispenser 140 applies adhesive between the optical device 10 after alignment and the connection target 200. The front end face of the optical device 10 and the rear end face of the connection target 200 are bonded together by this adhesive.

[0024] The processing unit 150 is composed of a computer and the like. The processing unit 150 drives the moving mechanism 110 to position the optical device 10 relative to the connection target 200. This positioning is performed to keep the distance between the optical axis of the optical fiber 30 and the optical axis of the optical waveguide 210 within a certain range. The processing unit 150 captures an image of the optical device 10 using the camera 121 or 122, and positions the optical device 10 based on the captured image. This point will be described in detail later. After positioning, the processing unit 150 performs alignment by active alignment. The processing unit 150 causes the light source 131 to emit a predetermined optical signal, and controls the moving mechanism 110 to move the optical device 10 relative to the connection target 200 until the optical signal is detected by the photodetector 132.

[0025] After the alignment, the processing unit 150 supplies adhesive from the dispenser 140 between the front end face of the optical device 10 and the rear end face of the connection target 200 to bond the optical device 10 and the connection target 200 together.

[0026] Here, a description will be given of the positioning process of the optical device 10 performed by the processing unit 150. In the following description, the left-right direction is the X-axis direction, the up-down direction is the Y-axis direction, and the front-rear direction is the Z-axis direction.

[0027] First, the processing unit starts capturing video of the optical device 10 and the connection target 200 using the camera 121 (step S11).

[0028] Then, while monitoring the captured image from the camera 121, the processing unit 150 controls the movement mechanism 110 to move the optical device 10 vertically, identify the position of the groove 22 in the captured image, and focus the camera 121 on a specific portion P of the groove 22 (a groove for image recognition) (step S12). The processing unit 150 may also rotate the optical device 10 so that the focus of the camera 121 is on the entire specific portion P. Here, the specific portion P (see FIG. 1 ) is the edge portion of the groove 22 (the connection portion between the upper surface of the substrate 20 and the inner surface of the groove 22), but it may also be the bottom end (valley bottom) of the V-shape of the groove 22. These portions have sharp corners with obtuse or acute angles, making it easy to obtain high contrast and focus. Note that in step S12, the camera 121 may be moved by a movement mechanism (not shown). Furthermore, since the optical fiber 30 is not disposed in the groove 22, the groove 22 and the optical fiber 30 do not overlap in the image captured by the camera 121, ensuring the accuracy of image recognition of the groove 22.

[0029] Because the focal length of the camera 121 is fixed, in step S12, for example, a position that is the focal length away from the position of the camera 121 becomes the Y coordinate (position in the vertical direction) of the specific part P of the groove 22. Furthermore, the X coordinate (position in the horizontal direction) of the specific part P of the groove 22 is also specified in detail by image processing using the above-mentioned arbitrary point of the groove 22 that is in focus. The processing unit 150 specifies the Y coordinate of the specific part P of the groove 22, and also specifies the X coordinate of the specific part P by image processing (step S13).

[0030] Thereafter, the processing unit 150 identifies the X and Y coordinates of the optical axis of a predetermined specific optical fiber 30 based on the X and Y coordinates of the specific portion of the groove 22 (step S14). The relative position of the optical axis of the optical fiber 30 in the X and Y axes directions with reference to the groove 22 is determined with high precision in design. Therefore, the processing unit 150 calculates the X and Y coordinates of the optical axis of the optical fiber 30 based on the dimensions of the optical device 10, which are prepared in advance. As another example, since the relative position of the optical axis of the optical fiber 30 in the X and Y axes directions with reference to the groove 22 is represented by a position vector from the groove 22, the processing unit 150 may calculate the X and Y coordinates of the optical fiber 30 based on the position of the groove 22 and the predetermined position vector.

[0031] Furthermore, the processing unit 150 performs image processing based on the image captured by the camera 121 to identify the X and Y coordinates of the optical axis of the optical waveguide 210 of the connection target 200, which is to be connected to any of the optical fibers 30 (step S15). Since the connection target 200 is formed of a silicon chip or the like, it is easy to obtain contrast between the optical waveguide 210 and its surroundings, and the dimensional accuracy is high, so the X and Y coordinates of the optical axis of the optical waveguide 210 of the connection target 200 can be identified by any method. A marker may be formed at any position on the connection target 200, and the processing unit 150 may identify the position of the marker by image processing, and then identify the position of the optical axis of the optical waveguide 210 from the identified position of the marker.

[0032] Thereafter, the processing unit 150 derives relative movement amounts (movement amounts in the X-axis direction and the Y-axis direction) of the optical device 10 that will bring the optical axes of the optical fiber 30 and the optical waveguide 210 to the same position in the X and Y directions, based on the X and Y coordinates of the optical axis of the optical fiber 30 identified in step S14 and the X and Y coordinates of the optical axis of the optical waveguide 210 identified in step S15 (step S16). The processing unit 150 controls the movement mechanism 110 to move the optical device 10 relative to the connection target 200 by the derived relative movement amounts (step S17). Note that the processing unit 150 may control the movement mechanism 110 based on the coordinates so as to align the optical axis of the optical fiber 30 and the optical axis of the optical waveguide 210 in the X and Y directions, and the specific method for controlling this is arbitrary. The processing unit 150 may control the moving mechanism 110 so that the optical axis of the optical waveguide 210 is parallel to the optical axis of the optical fiber 20 (e.g., the direction in which the specific portion P extends), and may rotate the optical device 10 and the connection object 200 relative to each other (such rotation may be performed during alignment).

[0033] Thereafter, the processing unit 150 controls the moving mechanism 110 to move the optical device 10 relative to the connection target 200 in the Z-axis direction, thereby bringing them closer to each other by a distance required for alignment (step S18). This process can be performed by any method. For example, the processing unit 150 determines the distance between them based on the captured image.

[0034] The positioning of the optical device 10 is completed through the above process. Subsequently, alignment of the optical device 10 and the connection target 200, bonding of the optical device 10 and the connection target 200, and the like are performed by any method, thereby producing an optical device unit in which the optical device and the connection target are connected. The camera image may be taken by the camera 122. Alternatively, both the camera 121 and the camera 122 may be used. If either the substrate 20 or the fixing member 40 is an opaque member, the camera may photograph the optical device from the transparent side. For example, the camera may also photograph the rear portion of the optical device, i.e., the portion where the fixing member 40 is not provided and the groove 22 is exposed. In such a case, the position (X coordinate and Y coordinate) of the groove 22 can be identified based on a directly photographed image of the groove, thereby improving the accuracy of image recognition.

[0035] In this embodiment, a groove 22 is provided in the substrate 20, which is easily recognized by image recognition due to the absence of an optical fiber therein. The position of this groove 22 is used as the reference position for identifying the position of the optical fiber 30 of the optical device 10 through image processing. While it is possible to use the outline of the substrate 20 or the fixing member 40 as this reference and identify the position of the optical fiber 30 from the outline position and design drawings, etc., the accuracy of the outline of the substrate 20 and the fixing member 40 is ±100 μm or greater. This is because the outline of the substrate 20 and the fixing member 40 does not require such high accuracy. On the other hand, the groove 22 opens on the same surface as the groove 21, extends parallel to the groove 21, and has a cross-section with the same shape as the cross-section of the groove 21. Therefore, the accuracy of the relative position between the grooves 21 and 22 can be achieved similarly to the accuracy of the relative position between conventionally provided grooves 21, i.e., with sub-μm accuracy. Therefore, the groove 22 can provide higher positioning accuracy for the optical device 10.

[0036] In this embodiment, the groove 22 has the same shape as the groove 21, but grooves of other shapes may also be used. Grooves are relatively easy to form, and higher positional accuracy than the above-mentioned outline is easily achieved. Therefore, even if a groove of a different shape from the groove 21 is adopted as the groove 22, the positioning accuracy of the optical device 10 is high. To ensure contrast during image recognition, the groove 22 preferably has a sharp corner that is an acute angle (at the bottom end of the V-shape) or an obtuse angle (at the edge portion of the groove 22). By having the grooves 21 and 22 be V-grooves with a V-shaped cross section, the sharp corners can be formed easily.

[0037] Here, it is conceivable to directly identify the position of the optical fiber 30 of the optical device 10 by image processing. However, the optical path from the camera 121 to the optical fiber 30 includes the fixing member 40, which makes it difficult to obtain a sufficient difference in refractive index between the optical fiber 30 and the fixing member 40. Furthermore, the cylindrical shape of the optical fiber 30 makes it easy for the optical path of the light used for measurement to be refracted. These factors make it difficult to directly observe the optical fiber 30, and it is therefore not desirable to directly identify the position of the optical fiber 30 by image processing. The same applies when photographing the optical device 10 with the camera 122 (the fixing member 40 replaces the substrate 20).

[0038] The optical device 10 and the connection target 200 are configured as an optical interconnect that performs optical communication not only for long-distance data transfer but also for short- to medium-distance transmission such as within a data center.

[0039] Next, modifications of this embodiment will be described. Some of the modifications may be combined with each other.

[0040] (Variation 1) The number of optical fibers 30 and the number of grooves 21 are arbitrary, and may be one each. A plurality of grooves 22 may be provided. For example, as shown in Fig. 5, a plurality of grooves 22 may be provided. The plurality of grooves 22 are parallel to one another and extend in the Z-axis direction (front-rear direction).

[0041] (Variation 2) As shown in FIG. 5 , the grooves 22 may be disposed between the optical fibers 30. In FIG. 5 , the grooves 22 are disposed between two adjacent grooves 21 among a plurality of grooves 21 disposed at equal intervals in the left-right direction. However, one of the plurality of equally spaced grooves may be designated as groove 22, and the remaining grooves, including the grooves on both the left and right sides of the designated groove 22, may also be designated as grooves 21. In such a case, all of the grooves, including grooves 21 and 22, are disposed at equal intervals. Here, if the plurality of optical fibers are configured as tape optical fibers, the pitch between the optical fibers will be a fixed value. When tape optical fibers are used and one of the plurality of equally spaced grooves is designated as groove 22, the optical fiber corresponding to the position of the groove 22 must be removed from the tape optical fiber. To avoid this, the grooves 22 may be formed between the optical fibers 30 disposed at equal intervals, i.e., between the equally spaced grooves 21. In this manner, the additional process of removing some of the optical fibers from the tape optical fiber can be omitted, thereby avoiding unnecessary cost increases associated with additional processes.

[0042] (Variation 3) As shown in FIG. 6 , the optical device 10 may include multiple grooves 22 that are parallel to one another. In this case, the processing unit 150 can accurately determine the X and Y coordinates of each groove 22. Furthermore, the processing unit 150 can determine the rotation angle of rotation about an axis along the front-to-rear direction of the groove 22 from the relationship between the X and Y coordinates of each groove 22. This is very useful, for example, when positioning an optical device 10 that includes optical fibers with multiple cores. In such a case, the processing unit 150 controls the moving mechanism 110 to rotate the optical device 10 relative to the connection target 200. Note that the relative rotation based on the determined rotation angle may be performed during alignment in addition to or instead of during positioning.

[0043] (Variation 4) In the above embodiment, the adhesive layer 50 fills the entire space between the substrate 20 and the fixing member 40. However, as shown in Fig. 7 , the adhesive layer 50 may be formed in a manner that avoids the region in the space between the substrate 20 and the fixing member 40 where the groove 22 is formed, and this region may be an air layer 90 into which the adhesive layer 50 does not enter.

[0044] As a result, if the amount of adhesive applied to the adhesive layer 50 material is small where the groove 22 is provided, for example, a portion with no refractive index may be formed, resulting in variations in refractive index and making image recognition difficult. If the groove 22 is filled with air, the refractive index in that region is uniform and no variations in refractive index occur, thereby improving the accuracy of image recognition of the groove 22.

[0045] As shown in FIG. 8 , the substrate 20 may have two grooves 23 that are parallel to each other and to the grooves 21 and 22. The two grooves 23 are located on both the left and right sides of the groove 22. The grooves 23 function to block the adhesive, which is the material of the adhesive layer 50, when the fixing member 40 is bonded, so that the adhesive does not infiltrate the area where the groove 22 is formed during application. Although it is possible to create the air layer 90 simply by controlling the amount of adhesive, controlling the amount of adhesive may be difficult depending on the viscosity. Therefore, grooves 23 are formed on both sides of the groove 22. By doing so, even if the amount of adhesive cannot be fully controlled when dripping adhesive into the area adjacent to the air layer 90, the overflowing adhesive is blocked by the grooves 23. Therefore, even if the amount of adhesive applied is increased by the volume of the grooves 23, the air layer 90 is formed. This makes it easier to form the air layer 90.

[0046] The two grooves 23 are formed in the same manner as the grooves 21 and 22, thereby reducing the effort required to form the grooves 23 using a new tool, etc. The grooves 23 block the adhesive, and the adhesive layer 50 then enters the grooves 23.

[0047] The groove 23 may be provided at least between the groove 22 and the groove 21. Since the optical fiber 30 is disposed in the groove 21, an adhesive is necessarily applied to fix the optical fiber 30. The groove 23 can dam up the applied adhesive.

[0048] The groove 22, along with the air layer 90, opens to the front end face of the optical device 10, to which the connection target 200 is bonded with adhesive. This allows the adhesive that bonds the connection target 200 to enter the air layer 90 and the groove. Because the connection target 200 is bonded after the above-described positioning, there is no problem if the adhesive penetrates the air layer 90 at this stage. This increases the adhesive strength. This is because the inner surface of the groove 22 and other surfaces come into contact with the adhesive. It is also known that adhesives generally exert more strength in the shear direction than in the peel direction. When the optical device 10 and the connection target 200 are bonded only end-to-end, the shear direction (up, down, left, and right directions) is only parallel to the end faces. In this state, when a tensile force is applied in a direction perpendicular to the end faces, the adhesive layer's adhesive strength in the tensile direction alone is required to withstand the force. On the other hand, if the connection object 200 is fixed to the optical device 10 by the adhesive that has entered the grooves 23, etc., the force in the tensile direction can also be absorbed as a shear force. Therefore, the adhesive strength in the tensile direction can be improved more than usual.

[0049] (Variation 5) As shown in Fig. 9, the substrate 20 may further include a groove 24 extending in a direction (left-right direction) perpendicular to the direction (front-back direction) in which the groove 22 extends. Fig. 9 shows a plan view of the substrate 20 of the optical device 10 on which optical fibers are arranged.

[0050] Like the groove 22, the groove 24 is also used for positioning. The groove 24 enables positioning of the optical device 10 in the front-to-rear direction of the optical device 10, i.e., the longitudinal direction of the optical fiber 30. This facilitates the positioning required, for example, when fabricating the optical device 10. Specifically, during the manufacturing process of the optical device 10, after the fixing member 40 is fixed, the front end face of the optical device 10, which is the connection surface of the optical device 10 with the connection target 200, is polished. This polishing makes the end faces of the optical fiber 30, substrate 20, etc. flush. When polishing, the amount of polishing must be controlled; for example, polishing is performed while observing the tip of the optical device 10. Because the tip of the optical device 10 has a uniform shape for several millimeters from the tip (the structure before and after the tip is partially removed is the same), it is difficult to estimate the amount of polishing before and after polishing based on images alone. However, by creating the groove 24 and determining the distance of the groove 24 from the end face, the amount of polishing can be easily measured from the image, allowing for efficient adjustment of the amount of polishing and achieving more accurate polishing than when the groove 24 is not used.

[0051] Although the groove 24 does not necessarily have to intersect with the groove 22, it is preferable that they do, as shown in FIG. 9 . This forms a cross mark at the intersection. By having the processing unit 150 focus on this cross mark, the S / N ratio during image recognition, in which the groove 22 and other elements are recognized, is improved. The image recognition ratio depends on the extent to which an area within the field of view (FOV) during image recognition has a structure that is easy to focus on. The FOV is generally a rectangular region. By including the area where the orthogonal grooves 22 and 24 intersect in the FOV, rather than including only one groove in the FOV, the area where the orthogonal grooves 22 and 24 intersect can be increased, even if the FOVs of both are the same. Therefore, creating orthogonal grooves 22 and 24 results in a higher S / N ratio, enabling more robust image recognition, even if there are noise elements within the FOV.

[0052] (Variation 6) The details of the positioning method of the optical device 10 described above are arbitrary. This positioning method may, for example, be a positioning method for positioning the optical device 10 relative to the connection target 200, and may include an imaging step of imaging the optical device 10 and the connection target 200, and a positioning step of identifying the positions of the grooves 22 based on the images captured in the imaging step and positioning the optical device 10 based on the identified positions of the grooves 22. For example, in the positioning step, the difference between the currently identified position of the grooves 22 and a predetermined position where the grooves 22 should be located (a position that achieves a desired positional relationship with the connection target 200) is calculated, and the optical device 10 is moved in a direction and by a distance that eliminates this difference. The position of the grooves 22 may be identified by pattern matching using a predetermined template image instead of focusing.

[0053] The positioning step may include, for example, a step of identifying the position of a specific optical fiber 30 based on an image captured by camera 121 or 122, and identifying the position of a waveguide 210 of the connection object 200 to be connected to the specific optical fiber 30, and a step of moving the optical fiber 30 relative to the connection object 200 so as to eliminate the difference between the identified position of the specific optical fiber 30 and the position of the waveguide 210.

[0054] (Variation 7) The hardware configuration of the processing unit 150 is arbitrary, and may be configured to include an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), etc. Furthermore, the image capturing by the camera to obtain the images to be used for image processing may not be video capturing, but may be periodic still image capturing, still image capturing at required timing, etc.

[0055] (Scope of the present invention) The present invention is not limited to the above-described embodiments and modifications. For example, the present invention includes various modifications to the above-described embodiments and modifications that can be understood by a person skilled in the art within the scope of the technical concept of the present invention. The configurations listed in the above-described embodiments and modifications can be combined as appropriate within a range that does not contradict. In addition, any of the above-described configurations can be deleted.

[0056] (Supplementary Notes) The following are exemplary configurations that exemplify the above-described embodiments and modifications disclosed in this specification. (Supplementary Note 1) An optical device configured to be optically connected to a connection target, comprising: at least one optical fiber; a substrate having at least one first groove in which the at least one optical fiber is disposed; and a fixing member that fixes the optical fiber to the substrate, wherein the substrate further comprises at least one second groove in which no optical fiber is disposed. (Supplementary Note 2) The optical device described in Supplementary Note 1, wherein the at least one second groove opens on the same surface of the substrate as the at least one first groove, is parallel to the at least one first groove, and has a cross section that is the same shape as the cross section of the first groove. (Supplementary Note 3) The optical device described in Supplementary Note 1 or 2, wherein the at least one second groove includes a pointed corner that is acute or obtuse. (Supplementary Note 4) The optical device according to any one of Supplements 1 to 3, wherein the at least one first groove and the at least one second groove are V-grooves having a V-shaped cross section. (Supplementary Note 5) The optical device according to any one of Supplements 1 to 4, wherein the at least one second groove includes a plurality of second grooves parallel to each other. (Supplementary Note 6) The optical device according to any one of Supplements 1 to 5, further comprising an adhesive layer filled in a space between the substrate and the fixing member and fixing the optical fiber and the fixing member to the substrate, the adhesive layer being formed so as to avoid a region of the space where the second groove is formed, the region being an air layer. (Supplementary Note 7) The optical device according to Supplementary Note 6, wherein the second groove reaches an end face of the optical device to which a connection object optically connected to the optical device is bonded with an adhesive. (Supplementary Note 8) The optical device according to Supplementary Note 6 or 7, wherein the substrate further comprises two third grooves parallel to the second groove, provided on both sides of the second groove, and having the adhesive layer embedded therein. (Supplementary Note 9) The optical device according to any one of Supplementary Notes 6 to 8, wherein the substrate further comprises a third groove parallel to the first groove and the second groove, provided between the second groove and the first groove, and having the adhesive layer embedded therein.(Supplementary Note 10) The optical device according to any one of Supplementary Notes 1 to 8, wherein the substrate further comprises a fourth groove extending in a direction perpendicular to a direction in which the second groove extends. (Supplementary Note 11) The optical device according to Supplementary Note 10, wherein the fourth groove is perpendicular to the second groove. (Supplementary Note 12) A method for positioning the optical device according to any one of Supplementary Notes 1 to 11 with respect to a connection object to which the optical device is optically connected, the method comprising: an imaging step of imaging the optical device and the connection object; and a positioning step of specifying a position of the second groove based on the captured image taken in the imaging step, and positioning the optical device based on the specified position of the second groove. (Supplementary Note 13) The method for positioning an optical device according to Supplementary Note 12, wherein the positioning step comprises the steps of: specifying a position of a specific optical fiber among the at least one optical fiber based on the captured image, and specifying a position of a waveguide of the connection object to be connected to the specific optical fiber, and moving the optical fiber relative to the connection object so as to eliminate a difference between the specified position of the specific optical fiber and the position of the waveguide. (Supplementary Note 14) A method for positioning an optical device according to Supplementary Note 11 or 12, and a step of aligning the combination of the optical device and the connection object positioned by the positioning method, and a step of bonding the optical device and the connection object in an aligned state.

[0057] 10...optical device, 20...substrate, 21 to 24...groove, 30...optical fiber, 40...fixing member, 50...adhesive layer, 90...air layer, 100...system, 110...moving mechanism, 121...camera, 122...camera, 131...light source, 132...photodetector, 140...dispenser, 150...processing unit, 200...connection object, 210...optical waveguide, P...specific part.

Claims

1. An optical device configured to be optically connected to a connection target, comprising: at least one optical fiber; a substrate having at least one first groove in which the at least one optical fiber is disposed; and a fixing member for fixing the optical fiber to the substrate, wherein the substrate further comprises at least one second groove in which no optical fiber is disposed.

2. The optical device according to claim 1, wherein the at least one second groove opens on the same surface of the substrate as the at least one first groove, is parallel to the at least one first groove, and has a cross section having the same shape as the cross section of the first groove.

3. The optical device according to claim 1, further comprising an adhesive layer that fills the space between the substrate and the fixing member and fixes the optical fiber and the fixing member to the substrate, the adhesive layer being formed so as to avoid the area of ​​the space where the second groove is formed, and the area being an air layer.

4. A method for positioning an optical device according to claim 1 relative to a connection object to which said optical device is optically connected, comprising: an imaging step of photographing said optical device and said connection object; and a positioning step of identifying the position of said second groove based on the image photographed in said imaging step, and positioning said optical device based on the identified position of the second groove.

Images