Optical connection structure
The optical connection structure uses ferrules with recesses and an adapter with matching protrusions to align optical fibers without guide pins, ensuring precise positioning and reducing connection loss by preventing foreign matter interference.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- SUMITOMO ELECTRIC INDUSTRIES LTD
- Filing Date
- 2021-09-17
- Publication Date
- 2026-05-11
AI Technical Summary
Existing optical fiber alignment methods using guide pins require high dimensional accuracy and are prone to positioning errors due to foreign matter interference, leading to increased connection loss.
An optical connection structure comprising ferrules with recesses or protrusions and an adapter with matching protrusions or recesses that allow ferrules to be positioned without guide pins, maintaining precise alignment and preventing foreign matter interference.
Facilitates easy and accurate positioning of multiple optical fibers with reduced connection loss by eliminating the need for high-precision guide pins and allowing easy removal of foreign matter, thus maintaining high precision and reducing costs.
Smart Images
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Figure 0007856570000003
Abstract
Description
Technical Field
[0004] ,
[0001] The present disclosure relates to an optical connection structure. This application claims priority based on Japanese Application No. 2020-161211 filed on September 25, 2020, and incorporates all the descriptions described in the Japanese application.
Background Art
[0002] Patent Document 1 discloses a technique for aligning multi-core optical fibers using guide pins. In this technique, one end of a pair of guide pins is inserted into a pair of guide pin insertion holes provided on the tip surface of a ferrule, and the other end of the pair of guide pins is inserted into a pair of guide pin insertion holes provided on the tip surface of the ferrule of the connection partner. Thereby, alignment of multi-core optical fibers (that is, alignment of a multi-core optical fiber and a multi-core optical fiber of a connection partner) is performed.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
[0004] This disclosure provides, in one aspect, an optical connection structure. This optical connection structure comprises a first ferrule, a second ferrule, and an adapter capable of housing the first and second ferrules internally. The first ferrule has a tip portion located at the end in a first direction, which is the direction in which the first ferrule is inserted into and removed from the adapter, and having a first light inlet / outlet portion formed thereon, and a first side surface and a second side surface facing each other in a second direction intersecting the first direction. The second ferrule has a tip portion located at the end in the first direction, and having a second light inlet / outlet portion formed thereon, and a first side surface and a second side surface facing each other in the second direction. The first side surface of the first ferrule and the first side surface of the second ferrule are provided with a first recess or a first protrusion. The first recess or first protrusion extends along the first direction. The second side surface of the first ferrule and the second side surface of the second ferrule are provided with a second recess or a second protrusion. The second recess or second protrusion extends along the first direction. The inner surface of the adapter is provided with a third protrusion or a third recess that can be fitted into the first recess of both the first and second ferrules, and a fourth protrusion or a fourth recess that can be fitted into the second recess of both the first and second ferrules. The first and second ferrules are fitted into the adapter such that when the first recess or first protrusion of both the first and second ferrules is fitted into the third protrusion or third recess of the adapter and the second recess or second protrusion of both the first and second ferrules is fitted into the fourth protrusion or fourth recess of the adapter, the tip of the first ferrule and the tip of the second ferrule face each other at a predetermined distance apart within the adapter, thereby optically connecting the first light input / output section and the second light input / output section. [Brief explanation of the drawing]
[0005] [Figure 1] Figure 1 is a perspective view showing an optical connector according to one embodiment. [Figure 2] Figure 2 is a perspective view showing the ferrule of the optical connector shown in Figure 1. [Figure 3]Figure 3 is a perspective view showing an optical connection structure in which a pair of optical connectors (ferrules) are optically connected within an adapter. [Figure 4] Figure 4 is a side view of the optical connection structure shown in Figure 3. [Figure 5] Figure 5 is a cross-sectional view of the optical connection structure shown in Figure 4. [Figure 6] Figure 6 is a plan view showing a pair of optical connectors (ferrules) separated by a predetermined distance when optically connected within an adapter. [Figure 7] Figure 7 is a schematic cross-sectional view showing an example of a light input / output section. [Figure 8] Figure 8 is a schematic cross-sectional view showing another example of a light input / output section. [Figure 9] Figure 9 is a perspective view showing the optical connection state in which a pair of optical connectors (ferrules) are optically connected within the adapter via the housing. [Figure 10] Figure 10 is a cross-sectional view of an optical connection structure according to a modified example. [Figure 11] Figure 11 is a cross-sectional view of an optical connection structure according to another modified example. [Modes for carrying out the invention]
[0006] [Issues this disclosure aims to address] When positioning multiple optical fibers using a guide pin and a ferrule provided with a guide pin insertion hole, as in the technology disclosed in Patent Document 1, the following problems may arise. For example, in order to position multiple optical fibers with high precision, a guide pin with high dimensional accuracy is required so that the clearance with the guide pin insertion hole is as small as possible. Furthermore, when cleaning the ferrule into which the guide pin is inserted, it may not be possible to completely remove foreign matter such as dust near the guide pin. In this case, such foreign matter may interfere, reducing the positioning accuracy of the multiple optical fibers and potentially increasing connection loss.
[0007] [Effects of this disclosure] According to the optical connection structure described herein, multiple optical fibers can be easily positioned with a simple configuration.
[0008] [Description of Embodiments in this Disclosure] First, the contents of the embodiments of this disclosure will be listed and described. An optical connection structure according to one embodiment of this disclosure comprises a first ferrule, a second ferrule, and an adapter capable of housing the first ferrule and the second ferrule internally. The first ferrule has a tip portion located at the end in a first direction, which is the direction in which the first ferrule is inserted into and removed from the adapter, and having a first light input / output portion formed thereon, and a first side surface and a second side surface facing each other in a second direction intersecting the first direction. The second ferrule has a tip portion located at the end in the first direction, and having a second light input / output portion formed thereon, and a first side surface and a second side surface facing each other in a second direction. The first side surface of the first ferrule and the first side surface of the second ferrule are provided with a first recess or a first protrusion. The first recess or first protrusion extends along the first direction. The second side surface of the first ferrule and the second side surface of the second ferrule are provided with a second recess or a second protrusion. The second recess or second protrusion extends along the first direction. The inner surface of the adapter is provided with a third protrusion or a third recess that can be fitted into the first recess of both the first and second ferrules, and a fourth protrusion or a fourth recess that can be fitted into the second recess of both the first and second ferrules. The first and second ferrules are fitted into the adapter such that when the first recess or first protrusion of both the first and second ferrules is fitted into the third protrusion or third recess of the adapter and the second recess or second protrusion of both the first and second ferrules is fitted into the fourth protrusion or fourth recess of the adapter, the tip of the first ferrule and the tip of the second ferrule face each other at a predetermined distance within the adapter, thereby optically connecting the first light input / output section and the second light input / output section.
[0009] In this optical connection structure, a first recess or first protrusion is provided on the first side surface of both ferrules to be optically connected, and a second recess or second protrusion is provided on the second side surface. Furthermore, the inner surface of the adapter into which both ferrules are inserted is provided with a third protrusion that can be fitted into the first recess or a third recess that can be fitted into the first protrusion, and a fourth protrusion that can be fitted into the second recess or a fourth recess that can be fitted into the second protrusion. When both ferrules are inserted into the adapter, the first recess fits into the third protrusion or the first protrusion fits into the third recess, and the second recess fits into the fourth protrusion or the second protrusion fits into the fourth recess, thereby defining the position of both ferrules relative to the adapter in a plane perpendicular to the first direction (i.e., the position of the multiple optical fibers held by each ferrule). In other words, with this optical connection structure, by using the adapter into which both ferrules are inserted and mated as a positioning member for positioning multiple optical fibers, it is possible to position the multiple optical fibers held by both ferrules without providing guide pin insertion holes in both ferrules. As a result, it becomes unnecessary to use guide pins with high dimensional accuracy for positioning multiple optical fibers. Furthermore, it is possible to avoid situations where the positioning accuracy of multiple optical fibers decreases due to the use of guide pins with foreign matter attached, thereby suppressing a decrease in connection loss.
[0010] Furthermore, in this optical connection structure, the first and second ferrules are designed to fit into the adapter such that when the first recess or first protrusion of each ferrule fits into the third protrusion or third recess of the adapter, and the second recess or second protrusion of each ferrule fits into the fourth protrusion or fourth recess of the adapter, the tip of the first ferrule and the tip of the second ferrule face each other at a predetermined distance within the adapter, thereby optically connecting the first light input / output section and the second light input / output section. In this case, since the tips of both ferrules are in a non-contact structure, even if foreign matter adheres to the tip of either ferrule, the impact on the distance between the two ferrules and the inclination of each ferrule can be reduced. In addition, because the end faces of both ferrules are in a non-contact optical connection structure, it is possible to prevent foreign matter adhering to the end faces from becoming fixed there by pressing, etc., and as a result, it becomes possible to easily remove foreign matter from the end faces with air or the like. Furthermore, this optical connection structure eliminates the need for conventional mating methods using guide pins, thus eliminating the need for expensive guide pins. This makes it possible to reduce costs while maintaining high precision in the optical connections between optical fibers held in each ferrule.
[0011] In one embodiment, the predetermined distance at which the tip of the first ferrule and the tip of the second ferrule are separated and facing each other when the first optical input / output section and the second optical input / output section are optically connected may be 0.05 mm or more and 2.0 mm or less. According to this embodiment, it is possible to optically connect both ferrules in a non-contact manner without reducing the optical coupling efficiency between the optical fibers held in each ferrule.
[0012] In one embodiment, the first ferrule, the second ferrule, and at least a portion of the adapter may be provided with a positioning structure for positioning the tip of the first ferrule and the tip of the second ferrule so that they face each other at a predetermined distance apart. By providing such a positioning structure, it becomes possible to more reliably connect the first light input / output section and the second light input / output section by positioning the tips of the first ferrule and the second ferrule so that they face each other at a predetermined distance apart within the adapter. In this embodiment, the first ferrule may further have a flange portion provided on the side opposite to the tip in the first direction, and whose width in the second direction is wider than that of the tip. The flange portion may function as part of a positioning structure that directly or indirectly positions the first ferrule relative to the adapter. The distance from one end of the flange portion of the first ferrule to the tip may be 2 mm or more and 10 mm or less. The second ferrule may also have a similar flange portion.
[0013] In one embodiment, any of the above-described optical connection structures may further include a housing for housing a first ferrule. The housing may be configured such that its movement along a first direction relative to the adapter is restricted. The movement of the first ferrule along the first direction relative to the housing may be restricted by a flange, thereby enabling the positioning of the first ferrule relative to the adapter. According to this embodiment, it is possible to easily position the ferrule relative to the adapter using a housing for manipulating the ferrule.
[0014] As one embodiment, at least one of the first optical input / output unit and the second optical input / output unit may be a lens array arranged along the second direction. In this case, the emitted light from each ferrule can be easily collimated, and it becomes possible to improve the optical coupling efficiency between the optical fibers held by both ferrules. In this embodiment, the lens array may be provided in a region recessed from the tip surface of the tip portion into the ferrule, and the tip of the lens array may be located inside the ferrule rather than the tip surface. In this case, it becomes easier to reduce the adhesion of foreign substances or the like to the lens surface of the lens array. On the other hand, the lens array may have a shape protruding from the tip surface of the tip portion to the outside of the ferrule. In this case, since the lens array protrudes and not only the tip of the lens array but also the base end side is exposed on the surface, the adhesion of foreign substances or the like to the lens array can be easily removed by a connector cleaner or the like. Of course, both the first optical input / output unit and the second optical input / output unit may be the above-described lens arrays.
[0015] As one embodiment, at least one of the third convex portion or the third concave portion and the fourth convex portion or the fourth concave portion of the adapter may be configured to be elastically deformable in the second direction. According to this embodiment, it becomes easier to insert the ferrule into the adapter, so the workability when inserting the ferrule into the adapter is improved. Further, when the ferrule is inserted into the adapter, when the first concave portion or the first convex portion and the second concave portion or the second convex portion come into contact with the third convex portion or the third concave portion and the fourth convex portion or the fourth concave portion, respectively, a force for at least one of the third convex portion or the third concave portion and the fourth convex portion or the fourth concave portion to return to its original position is applied to the ferrule. Thereby, since the ferrule is sandwiched and fixed by the third convex portion or the third concave portion and the fourth convex portion or the fourth concave portion, displacement of the ferrule with respect to the adapter is suppressed. As a result, the positioning of a plurality of optical fibers can be performed with high accuracy.
[0016] [Details of Embodiments of the Present Disclosure] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. The present invention is not limited to these examples, and is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the following description, the same reference numerals will be used for the same elements or elements having the same function, and redundant descriptions will be omitted.
[0017] First, the configurations of the optical connector 1 and the ferrule 10 used in the optical connection structure according to this embodiment will be described with reference to FIGS. 1 and 2. In the optical connection structure according to this embodiment, the optical input / output portions (such as a lens array) of a pair of optical connectors 1 are opposed to each other using an adapter 20 (see FIG. 3) described later to perform optical connection. FIG. 1 is a perspective view showing an optical connector 1 according to an embodiment. FIG. 2 is a perspective view showing the ferrule 10 which is a main component of the optical connector 1 shown in FIG. 1. In FIGS. 1 and 2, an XYZ orthogonal coordinate system is shown for easy understanding. The same applies to other figures. In this embodiment, the direction in which the optical connector 1 (ferrule 10) is inserted into and removed from the adapter 20 in the longitudinal direction of the optical connector 1 is defined as the Z direction (first direction), the short-side direction of the optical connector 1 is defined as the Y direction (second direction), and the height direction of the optical connector 1 is defined as the X direction (third direction).
[0018] As shown in FIG. 1, the optical connector 1 includes an optical fiber ribbon core wire 4 that houses a plurality of optical fibers 3, and a ferrule 10 attached to the tip of the optical fiber ribbon core wire 4. Each optical fiber 3 of the optical fiber ribbon core wire 4 extends along the Z direction and is arranged side by side along the Y direction that intersects (for example, is orthogonal to) the Z direction. The optical fiber ribbon core wire 4 may have a configuration in which a plurality of optical fibers 3 are arranged in a plurality of layers and overlap inside. The plurality of optical fibers 3 are arranged or inserted and held along the Z direction in a plurality of optical fiber grooves 11c or a plurality of optical fiber holding holes formed inside the ferrule 10.
[0019] As shown in Figures 1 and 2, the ferrule 10 is a component that holds each end of the optical fiber 3 and optically couples these optical fibers 3 to another optical fiber held by another optical connector (ferrule). The ferrule 10 comprises a main body portion 11, a flange portion 12, side surfaces 13, 14 (first side surface, second side surface), recesses 15, 16 (first recess, second recess), a tip portion 17, a rear end portion 18, and a lens array 19 (first light input / output portion, second light input / output portion). The ferrule 10 is made of a material such as polyphenylene sulfide (PPS), polyetherimide (PEI), polycarbonate (PC), polymethyl methacrylate (PMMA), polyethersulfone (PES), or cycloolefin polymer (COP). The ferrule 10 may be entirely made of a light-transmitting resin, or at least the region between the lens array 19 and the tip of the optical fiber 3 may be made of a light-transmitting resin. 1 Other optical connectors that are coupled to the optical connector 1 It has a similar configuration to the previous one.
[0020] The main body portion 11 has a roughly rectangular parallelepiped shape. The upper surface of the main body portion 11 is provided with windows 11a and 11b that open toward the inside of the ferrule, and multiple optical fiber grooves 11c for holding multiple optical fibers 3 are formed inside the window portion 11a. The multiple optical fiber grooves 11c are, for example, V-grooves or U-grooves and extend along the Z direction. In addition, a storage portion (internal space) is formed inside the main body portion 11, extending from the opening of the rear end portion 18 toward the optical fiber grooves 11c, and each end of the optical fiber 3 inserted from the opening of the rear end portion 18 passes through the storage portion and is placed in the optical fiber grooves 11c. Each optical fiber 3 placed in the optical fiber grooves 11c is optically coupled to each lens portion of the lens array 19. The storage portion is configured to connect to the windows 11a and 11b, and after the optical fibers 3 are stored in the optical fiber grooves 11c, the lid portion 6 is placed over the window portion 11a from above in the X direction, and the optical fibers 3 are pushed into the optical fiber grooves 11c. The optical fiber 3 is then fixed to multiple optical fiber grooves 11c, etc., by adhesive or the like injected through the window portion 11a (the gap with the lid portion 6).
[0021] The flange portion 12 is located at the rear end of the main body portion 11 in the Z direction, and is formed such that the flange portion 12 is larger than the main body portion 11 in a cross-sectional shape along the XY plane. The stepped portion of this flange portion 12 determines the position of the ferrule 10 in the Z direction relative to the adapter into which the ferrule 10 is inserted or the housing that houses the ferrule 10. In other words, the flange portion 12 functions as part of a positioning structure that directly or indirectly positions the ferrule 10 relative to the adapter 20. In the ferrule 10, portions other than the flange portion 12 may also be part of such a positioning structure.
[0022] The two sides 13 and 14 are sides of the main body 11 that face each other in the Y direction, with a recess 15 provided on side 13 and a recess 16 on side 14. The recesses 15 and 16 are, for example, V-grooves or U-grooves extending in the Z direction, and function as guide grooves when inserting or removing the ferrule 10 from the adapter. The recesses 15 and 16 do not have to be formed on the flange portion 12, or they may extend to the flange portion 12. If the cross-sectional shape of the recesses 15 and 16 is a V-groove, the opening angle of the V-groove (i.e., the angle made by the pair of surfaces constituting the V-groove) in a cross section perpendicular to the Z direction may be, for example, 45° or more and 150° or less, 60° or more and 100° or less, or 90°. The bottom of the V-groove constituting the recesses 15 and 16 may be, for example, rounded in a cross section perpendicular to the Z direction. Furthermore, the recesses 15 and 16 may have a semicircular cross-section, as long as they are configured to be positioned by contacting the protrusions of the adapter 20, which will be described later.
[0023] The recess 15 has two positioning portions 15a and 15b, a stepped portion 15c located between the positioning portions 15a and 15b, a stepped portion 15d located outside the positioning portion 15a, and a stepped portion 15e located between the positioning portion 15b and the flange portion 12. Each stepped portion 15c, 15d, and 15e is recessed inward from the respective surfaces of the positioning portions 15a and 15b. When the ferrule 10 is inserted into the adapter 20, the positioning portions 15a and 15b contact the protrusions 24 or 25 of the adapter 20 (see Figure 3), while the stepped portions 15c, 15d, and 15e do not contact (or only slightly touch) the protrusions 24 or 25 of the adapter 20. In other words, the positioning portions 15a and 15b determine one position of the ferrule 10 relative to the adapter 20. The amount of recess in the stepped portions 15c, 15d, and 15e is such that, for example, the difference between the surfaces of the positioning portions 15a and 15b and the bottom surfaces of each stepped portion 15c, 15d, and 15e is 0.01 mm or more.
[0024] Each positioning portion 15a, 15b is separated from each other in the Z-axis direction, but this separation distance may be, for example, 3 mm or more and 10 mm or less. The separation distance here refers to the shortest separation distance between the two positioning portions, for example, the distance between the end of positioning portion 15a closer to positioning portion 15b and the end of positioning portion 15b closer to positioning portion 15a. Furthermore, positioning portion 15a is formed inward so that its end is at least 0.1 mm away from the tip surface 17a of the adjacent tip portion 17 of the ferrule 10 in the Z-axis direction, and positioning portion 15b is formed inward so that its end is at least 0.1 mm away from the adjacent flange portion 12 of the ferrule 10 in the Z-axis direction. In addition, each positioning portion 15a, 15b may have a width along the Z-axis direction of 0.2 mm or more and 3 mm or less. By having a certain width in this way, when inserted into the adapter 20, it is possible to secure a contact area with the adapter 20 and function as a point for more appropriate positioning of the ferrule 10 (i.e., the multiple optical fibers 3 held) relative to the adapter 20.
[0025] The recess 16, like the recess 15, has two positioning portions 16a and 16b, a stepped portion 16c located between the positioning portions 16a and 16b, a stepped portion 16d located outside the positioning portion 16a, and a stepped portion 16e located between the positioning portion 16b and the flange portion 12. The recess 16 has a shape symmetric to the recess 15 with respect to a central axis that passes through the center of the ferrule 10 in the Y direction and extends in the Z direction. The positioning portions 16a and 16b have a shape symmetric to the positioning portions 15a and 15b, and the stepped portions 16c, 16d, and 16e have a shape symmetric to the stepped portions 15c, 15d, and 15e (i.e., a left-right symmetric shape). For this reason, the positioning portions 16a and 16b are provided on the side surface 14 so that they are in the same position in the Z direction as the positioning portions 15a and 15b on the side surface 13. Furthermore, each stepped portion 16c, 16d, and 16e is recessed inward from the ferrule 10 compared to the surfaces of the positioning portions 16a and 16b. In other words, the positioning portions 16a and 16b protrude slightly outward from the stepped portions 16c, 16d, and 16e, and the positioning portions 16a and 16b determine the other position of the ferrule 10 relative to the adapter 20. The other configurations of the positioning portions 16a and 16b and the stepped portions 16c, 16d, and 16e are the same as those of the positioning portions 15a and 15b and the stepped portions 15c, 15d, and 15e described above, and a detailed explanation is omitted. Note that the recesses 15 and 16 do not have to be symmetrical in shape, and the distances of the positioning portions from the ferrule tip and the distances between the positioning portions may differ from each other.
[0026] In a ferrule 10 having such a side configuration, the distance between the bottoms of the positioning portions 15a and 15b of the recess 15 and the bottoms of the positioning portions 16a and 16b of the recess 16, which are opposite to each other along the Y direction, may be formed to be slightly wider than the distance between the tips of the protrusions 24 and 25 of the adapter 20. As a result, when the ferrule 10 is inserted into the adapter 20, the clearance is made zero by the positioning portions 15a and 15b of the recess 15 and the positioning portions 16a and 16b of the recess 16, and the ferrule 10 is positioned in a predetermined position relative to the adapter 20.
[0027] The tip portion 17 is located at the end of the ferrule 10 in the Z direction and is the portion where the lens array 19 is provided. The lens array 19 is provided in a region of the tip portion 17 that is recessed backward along the Z direction from the tip surface 17a. The lens array 19 includes a plurality of lens portions aligned in the Y direction. Each lens portion is, for example, a collimating lens and is optically coupled to each tip of the optical fiber 3 arranged in the optical fiber groove 11c from the inside of the ferrule. For this reason, in the ferrule 10, each optical fiber groove 11c that holds the optical fiber 3 corresponds to each lens portion of the lens array 19. In addition, the tip portion 17 has a projection 17b that protrudes forward from the tip surface 17a and is provided below the lens array 19. Alternatively, instead of the lens array 19, through holes corresponding to each optical fiber 3 may be provided as optical input and output portions so that the tips of the optical fibers 3 can be inserted directly and exposed to the tip portion 17 (or tip surface 17a). In this case, the optical fiber 3 may be one with a lens pre-attached to its tip (such as a GRIN lens or a rod lens with an aspherical tip), or it may be an optical fiber without such lenses used as is.
[0028] Next, with reference to Figures 3, 4, and 5, an optical connection structure 100 that optically connects optical connectors 1 (ferrules 10) having the above-described configuration via an adapter 20 will be explained. Figure 3 is a perspective view showing an optical connection structure in which a pair of ferrules 10 (shown as ferrules 10A and 10B, respectively; their structures are the same) are optically connected within the adapter 20. Figure 4 is a side view of the optical connection structure shown in Figure 3. Figure 5 is a cross-sectional view of the optical connection structure shown in Figure 4. In Figures 3 to 5, for the sake of clarity, only the ferrules 10 (10A, 10B) of the optical connector 1 are shown, and optical fibers 3, etc., are omitted. In addition, in the optical connection structure 100, ferrules 10A and ferrules 10B are optically connected with their top and bottom reversed in the X direction, but they may also be optically connected in the same state without reversal.
[0029] First, the configuration of the adapter 20 used in the optical connection structure 100 will be described. As shown in Figures 3 to 5, the adapter 20 is a cylindrical member that holds a pair of ferrules 10A and 10B facing each other inside it for optical connection. Such an adapter 20 is made of an elastic material such as polyetherimide (PEI), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polycarbonate (PC), polymethyl methacrylate (PMMA), polyethersulfone (PES), or polyamide (PA). In order to reduce the difference between the coefficient of thermal expansion of the material of the adapter 20 and the coefficient of thermal expansion of the materials of the ferrules 10A and 10B, it is preferable to use the same type of material as the ferrules 10A and 10B for the material of the adapter 20. In addition, the material of the adapter 20 may contain fillers or additives to improve sliding properties.
[0030] The adapter 20 has a housing section 23 that opens at the first opening 21 and the second opening 22, and houses the ferrules 10A and 10B within the housing section 23. The housing section 23 is a hole that penetrates from the first opening 21 to the second opening 22, and as shown in Figure 5, its internal space is defined by a pair of sides 23a, 23b and a pair of sides 23c, 23d. In the optical connection structure 100, for example, the ferrule 10A is inserted into the housing section 23 from the first opening 21, and the ferrule 10B is inserted into the housing section 23 from the second opening 22. The adapter 20 engages with the ferrules 10A and 10B such that the tip 17 of the ferrule 10A and the tip 17 of the ferrule 10B to be connected face each other in the housing section 23. As will be explained in more detail later, inside the adapter 20, the tip 17 of ferrule 10A and the tip 17 of the ferrule 10B that it connects to are configured to be optically connected at a predetermined distance from each other (see Figure 6).
[0031] The sides 23c and 23d of the housing section 23 of the adapter 20 are provided with protrusions 24 and 25 (third and fourth protrusions) that face each other in the Y direction. The protrusions 24 and 25 project inward toward the inside of the adapter 20 and, when the ferrules 10A and 10B are inserted into the adapter 20, they enter into and contact the recesses 15 and 16 (more specifically, the positioning sections 15a and 15b and the positioning sections 16a and 16b) of each ferrule 10A and 10B, and guide the insertion of the ferrules 10A and 10B into and out of the adapter 20. The protrusions 24 and 25 have sufficient length in the Z direction to reliably guide and hold the pair of ferrules 10A and 10B into the housing section 23. For example, the protrusions 24 and 25 extend in the Z direction such that both the distance between the ends of the protrusion 24 and the distance between the ends of the protrusion 25 are longer than the distance in the Z direction between the two positioning portions 15b (or 16b) when the tips of the pair of ferrules 10A and 10B are placed at a predetermined distance apart.
[0032] A gap 26 may be provided on the outside of the protrusion 24 of the adapter 20 in the Y direction. By providing the gap 26, the protrusion 24 can easily move elastically outward in the Y direction. Therefore, even if the protrusions 24 and 25 of the adapter 20 are formed to be slightly narrow so as to ensure reliable contact with the recesses 15 and 16 of the ferrules 10A and 10B, the protrusion 24 can move outward and be adjusted when the adapter 20 is inserted. In the adapter 20, the elastic movement outward of the protrusion 24 and its strength can be adjusted by adjusting the thickness and extension angle of the support portion 24a that supports the protrusion 24 with respect to the X direction (for example, by tilting it). In addition, a gap such as the gap 26 may be provided on the outside of the protrusion 25.
[0033] With the adapter 20 having this configuration, ferrule 10A is inserted through the first opening 21 and ferrule 10B is inserted through the second opening 22, so that their respective tip portions 17 are separated and facing each other. This constitutes the optical connection structure 100. In this optical connection structure 100, each of the ferrules 10A and 10B is provided with recesses 15 and 16, and the adapter 20 includes protrusions 24 and 25, so that even without providing guide pins on the ferrules, when the ferrules 10A and 10B are inserted into the adapter 20, the ferrules 10A and 10B (i.e., optical connectors) are connected to the adapter 20. 1 The ferrules 10A and 10B can be positioned by restricting the positions of multiple optical fibers 3) in the X and Y directions and their rotations around each of the XYZ axes. As a result, it becomes unnecessary to use guide pins with high dimensional accuracy for positioning multiple optical fibers 3. Furthermore, it is possible to avoid situations where the positioning accuracy of multiple optical fibers 3 decreases due to the use of guide pins with foreign matter attached, thereby suppressing the decrease in connection loss.
[0034] Next, referring to Figure 6, in the optical connection structure 100, a pair of ferrules 10A, 10B (optical connectors) 1 The optical connection state in which two ferrules (10A and 10B) are facing each other at a predetermined distance apart will be explained in more detail. Figure 6 is a plan view showing the state in which a pair of ferrules 10A and 10B are facing each other at a distance when optically connected within the adapter 20. Note that in Figure 6, the adapter 20 and optical fiber 3 are omitted for the sake of clarity.
[0035] In the optical connection structure 100, as described above, the positioning of the pair of ferrules 10A and 10B is performed not by using guide pins for positioning, but by fitting recesses 15 and 16 provided on the sides of the adapter 20 into protrusions 24 and 25. That is, when the recess 15 or 16 of each ferrule 10A and 10B is fitted into the protrusion 24 of the adapter 20 and the recess 16 or 15 of each ferrule 10A and 10B is fitted into the protrusion 25 of the adapter 20, the tip 17 of ferrule 10A and the tip 17 of ferrule 10B face each other at a predetermined distance apart within the adapter 20, and the ferrules are fitted into the adapter 20 in such a way that they optically connect the lens array 19 of ferrule 10A and the lens array 19 of ferrule 10B. In the optical connection structure 100, for positioning the ferrules 10A and 10B, for example, as described above, the stepped portion of the flange 12 of each ferrule is brought into contact with the inner surface of the adapter 20, etc., so that the ferrules 10A and 10B face each other in a non-contact state.
[0036] In this optical connection structure 100, as shown in Figure 6, if the distance between the flanges 12 of both ferrules 10A and 10B is L1, the distance from the flange 12 to the tip 17 (tip surface 17a) of each ferrule 10A and 10B is L2, and the distance between the tip 17s is L3, then the relationship L3 = L1 - L2 × 2 holds. Here, distance L3 more precisely means the distance between opposing lens arrays 19, or, if there are no lenses, the distance between opposing tip surfaces of the optical fibers 3. The distance L2 from the flange 12 to the tip 17 of each ferrule 10A and 10B is not particularly limited, but in the case of small ferrules, it may be, for example, 2 mm or more and 10 mm or less. Also, the distance L3 between the tip 17 of ferrule 10A and the tip 17 of ferrule 10B is not particularly limited, but in the case of small ferrules, it may be, for example, 0.05 mm or more and 2.0 mm or less. In the optical connection structure 100, the ferrules 10A and 10B are non-contact as described above, and the protrusions 17b of each ferrule 10A and 10B also do not come into contact with each other. The protrusions 17b do not need to be provided. In this way, the optical connection structure 100 optically connects both ferrules 10A and 10B in a non-contact manner without reducing the optical coupling efficiency between the optical fibers 3 held by each ferrule 10A and 10B.
[0037] As described above, in the optical connection structure 100 according to this embodiment, recesses 15 are provided on the side surface 13 of both ferrules 10A and 10B to be connected, and recesses 16 are provided on the side surface 14. Furthermore, a protrusion 24 that can be fitted into the recess 15 and a protrusion 25 that can be fitted into the recess 16 are provided on the inner surface of the adapter 20. When both ferrules 10A and 10B are inserted into the adapter 20, the recess 15 fits into the protrusion 24 and the recess 16 fits into the protrusion 25, thereby defining the positions of both ferrules 10A and 10B relative to the adapter 20 in a plane perpendicular to the Z direction (i.e., the positions of the multiple optical fibers 3 held by each of the ferrules 10A and 10B). In other words, with this optical connection structure 100, by using the adapter 20 into which both ferrules 10A and 10B are inserted and fitted as a positioning member when positioning the multiple optical fibers 3, the multiple optical fibers 3 can be positioned without providing guide pin insertion holes in the ferrules 10. As a result, it becomes unnecessary to use guide pins with high dimensional accuracy for positioning multiple optical fibers 3. Furthermore, it is possible to avoid situations where the positioning accuracy of multiple optical fibers 3 decreases due to the use of guide pins with foreign matter attached, thereby suppressing the decrease in connection loss.
[0038] Furthermore, in this optical connection structure 100, the ferrules 10A and 10B can be fitted into the adapter 20 such that when the recesses 15 of each ferrule 10A and 10B are fitted into the protrusions 24 of the adapter 20 and the recesses 16 are fitted into the protrusions 25, the tip 17 of ferrule 10A and the tip 17 of ferrule 10B face each other at a distance L3 within the adapter 20, thereby optically connecting the lens array 19 of ferrule 10A and the lens array 19 of ferrule 10B. Because the tip 17s of both ferrules 10A and 10B are in a non-contact structure, even if foreign matter adheres to the tip of either ferrule, the impact on the distance between the two ferrules 10A and 10B and the inclination of each ferrule 10A and 10B can be reduced. Furthermore, since the tips 17 of both ferrules 10A and 10B have a non-contact structure, it prevents foreign matter adhering to the tips 17 from becoming fixed due to pressure, etc., making it possible to easily remove foreign matter from the tips 17 with air or the like. Moreover, this optical connection structure 100 eliminates the need for conventional fitting methods using guide pins, thus eliminating the need for expensive guide pins and making it possible to reduce costs while maintaining high precision in the optical connection between the optical fibers 3 held by each ferrule 10A and 10B.
[0039] Furthermore, in this embodiment, a lens array 19 is provided at the tip portion 17 as the light input and output portions of each ferrule 10A and 10B. Therefore, the light emitted from each ferrule 10A and 10B can be easily converted into collimated light, and the optical coupling efficiency between the optical fibers 3 held by both ferrules 10A and 10B can be increased. The lens array 19 does not have to convert the light incident from the optical fiber 3 into collimated light in the strict sense, as long as the coupling efficiency is within an acceptable range.
[0040] Furthermore, in this embodiment, the lens array 19 is provided in a region recessed into the ferrule from the tip surface 17a of the tip portion 17, and the tip of the lens array 19 is located further inside the ferrule than the tip surface 17a. This reduces the adhesion of foreign matter to the lens surface of the lens array 19. As an example of such a lens array, the lens array 19A shown in Figure 7 can also be used. In the lens array 19A shown in Figure 7, there is also a visor above the lens portion, and the lens array 19A is positioned more securely inward. In this case, the adhesion of foreign matter to the lens surface 19a of the lens array 19A can be further reduced. Conversely, in the ferrules 10A and 10B, as shown in Figure 8, a lens array 19B having a shape that protrudes outside the ferrule from the tip surface 17a of the tip portion 17 may be provided as the light input and output portion. In this case, the lens array 19B protrudes from the tip surface 17a, and since both the tip and base end of the lens surface 19b are exposed to the surface, foreign matter and other contaminants adhering to the lens array 19B can be easily removed with a connector cleaner or the like. In the optical connection structure 100 according to this embodiment, since the ferrules 10A and 10B are arranged opposite each other in a non-contact state, even with such a protruding lens array 19B, the optically required inter-lens distance can be sufficiently secured.
[0041] Furthermore, in this embodiment, the protrusions 24 and 25 (especially the protrusion 24) of the adapter 20 are configured to be elastically deformable in the Y direction. This configuration makes it easier to insert the ferrules 10A and 10B into the adapter 20, thereby improving workability when inserting the ferrules 10A and 10B into the adapter 20. Also, when the recesses 15 and 16 come into contact with the protrusions 24 and 25 respectively when inserting the ferrules 10A and 10B into the adapter 20, a force is applied to the ferrules 10A and 10B that causes the protrusions 24, etc., to return to their original positions. As a result, the ferrules 10A and 10B are more securely held and fixed by the protrusions 24 and 25, thereby suppressing misalignment of the ferrules 10A and 10B relative to the adapter 20. Consequently, the positioning of the multiple optical fibers 3 held by each ferrule 10A and 10B can be performed with high precision.
[0042] The optical connection structure relating to this disclosure has been described above, but this disclosure is not limited to the embodiments described above and can be modified as appropriate without departing from the spirit of the claims.
[0043] For example, as shown in Figure 9, the above-described arrangement of housings 30A and 30B that hold the ferrules 10A and 10B may be applied to the optical connection structure 101, which is provided with housings 30A and 30B that hold the ferrules 10A and 10B described above. In this case, each ferrule 10A and 10B is restricted from moving toward the tip along the Z-axis direction by bringing its flange portion 12, which is biased toward the tip by a spring, into contact with the column portions 31A and 31B of the housings 30A and 30B. The flange portion 12 and the column portions 31A and 31B function as part of the positioning structure. Then, each housing 30A and 30B is restricted from moving toward the tip along the Z-direction by bringing its latches 32A and 32B into contact with the inner surface of the adapter 20. The contact portion between the latches 32A and 32B and the adapter 20 functions as another part of the positioning structure. Even with this housing configuration, the ferrules 10A and 10B are indirectly positioned relative to the adapter 20, making it possible to perform optical connection while they are positioned at a distance from each other. In the modified example shown in Figure 9, the above configuration allows for positioning without the flanges 12 of the ferrules 10A and 10B contacting the adapter 20. However, the sides 13 and 14 of the ferrules 10A and 10B are inserted into the adapter 20 so as to contact the protrusions inside the adapter 20.
[0044] Furthermore, in the above embodiment, recesses 15, 16 (grooves) are formed on the sides 13, 14 of the ferrule 10, and protrusions 24, 25 are formed on the inner surface of the adapter 20, with the protrusions 24, 25 fitting into the recesses 15, 16. cumIn this configuration, the ferrule 10 was positioned relative to the adapter 20. However, as shown in Figure 10, conversely, protrusions 115 and 116 (first and second protrusions) may be formed on the sides 113 and 114 of the ferrule 110, and recesses 154 and 155 (third and fourth recesses) may be provided on the sides 152 and 153 of the adapter 150, so that each ferrule 110 can be inserted into the adapter 150. The basic configuration of each ferrule 110, except for the side shape, is the same as that of the ferrule 10. In this modified configuration, the protrusion 115 formed on the side 113 of the ferrule 110 may be provided with two positioning parts 115a and 115b, and the protrusion 116 formed on the side 114 of the ferrule 110 may be provided with two positioning parts 116a and 116b. The two positioning portions 115a, 115b and the two positioning portions 116a, 116b are formed apart from each other in the longitudinal direction (Z direction, the direction perpendicular to the plane of the paper in Figure 10), similar to the positioning portions 15a, 15b and 16a, 16b of the ferrule 10, and are configured to protrude slightly outward from the other parts (stepped portions) of the side surfaces 113 and 114. Also, as shown in Figure 11, the protrusions 115A, 116A on the side surfaces 113A, 114A of each ferrule 110A may be semicircular or elliptical, and two positioning portions 117a, 117b and two positioning portions 118a, 118b may be provided on such shaped side surfaces 113A, 114A, respectively. The two positioning portions 117a, 117b and the two positioning portions 118a, 118b are formed apart from each other in the longitudinal direction (Z direction), similar to the positioning portions 15a, 15b and 16a, 16b of the ferrule 10, and protrude slightly outward from the other parts (stepped portions) of the side surfaces 113A and 114A. The basic configuration of the ferrules 110 and 110A, excluding the side shape, is the same as that of the ferrule 10, and detailed descriptions are omitted in Figures 10 and 11.
[0045] Furthermore, in the above embodiment, the adapter 20 is made of, for example, an elastic material, but it may also be made of a material that does not elastically deform (or a material that does not elastically deform substantially). In this case, the distance between the bottoms of the recesses 15 and 16 of the ferrules 10A and 10B may be the same as or slightly narrower than the distance between the tips of the protrusions 24 and 25 of the adapter 20. With such a configuration, even if the adapter 20 does not elastically deform, the positions of both ferrules 10A and 10B relative to the adapter 20 (i.e., the positions of the multiple optical fibers 3 held by each of the ferrules 10A and 10B) can be appropriately defined in a plane perpendicular to the Z direction. [Explanation of Symbols]
[0046] 1… Optical connector 3… Fiber optic 4… Fiber optic ribbon 6…Lid part 10, 10A, 10B, 110, 110A… ferrules 11...Main body 11a, 11b... Window section 11c… Optical fiber groove 12... Guard part 13,113,113A…Side (1st side) 14,114,114A…Side (second side) 15…Recess (First recess) 15a, 15b, 115a, 115b, 117a, 117b... Positioning parts 15c, 15d, 15e... Stepped sections 16…Recess (Second recess) 16a, 16b, 116a, 116b, 118a, 118b... Positioning parts 16c, 16d, 16e... Stepped sections 17...Tip 17a…Tip surface 17b...Protruding part 18...Rear end 19, 19A, 19B... Lens array (first light input / output section, second light input / output section) 19a, 19b… Lens surface 20,150…Adapter 21…First opening 22...Second opening 23...Storage section 23a,23b,23c,23d,152,153…side 24...Convex part (3rd convex part) 24a...Support part 25...Convex part (4th convex part) 26...Void 30A, 30B… Housing 31A, 31B…Column part 32A, 32B… latches 100,101…Optical connection structure 115, 115A... protrusion (first protrusion) 116, 116A... protruding section (second protruding section) 154... Recess (Third recess) 155... Recess (4th recess)
Claims
1. The first ferrule and, The second ferrule and, A first housing for housing the first ferrule, The device comprises an adapter capable of housing the first ferrule and the second ferrule inside, The first ferrule has a tip portion located at the end in a first direction, which is the direction in which the first ferrule is inserted into and removed from the adapter, and having a first light inlet / outlet portion formed thereon; first and second sides facing each other in a second direction intersecting the first direction; and a flange portion provided on the side opposite to the tip portion in the first direction, with a width in the second direction that is wider than that of the tip portion. The second ferrule has a tip portion located at the front in the first direction and having a second light inlet / outlet portion formed thereon, and a first side surface and a second side surface facing each other in the second direction, The first side surface of the first ferrule and the first side surface of the second ferrule are provided with a first recess or first protrusion extending along the first direction, and the second side surface of the first ferrule and the second side surface of the second ferrule are provided with a second recess or second protrusion extending along the first direction. The inner surface of the adapter is provided with a third protrusion that can be fitted into the first recess of both the first ferrule and the second ferrule, or a third recess that can be fitted into the first protrusion of both the first ferrule and the second ferrule, and a fourth protrusion that can be fitted into the second recess of both the first ferrule and the second ferrule, or a fourth recess that can be fitted into the second protrusion of both the first ferrule and the second ferrule. The first ferrule and the second ferrule are fitted into the adapter such that when the first recess or first protrusion of both the first ferrule and the second ferrule are fitted into the third protrusion or third recess of the adapter, and the second recess or second protrusion of both the first ferrule and the second ferrule are fitted into the fourth protrusion or fourth recess of the adapter, the tip of the first ferrule and the tip of the second ferrule face each other at a predetermined distance apart within the adapter, thereby optically connecting the first light input / output section and the second light input / output section. At least a portion of the first ferrule, the second ferrule, and the adapter is provided with a positioning structure for positioning the tip of the first ferrule and the tip of the second ferrule facing each other at a predetermined distance apart, and the flange of the first ferrule functions as part of the positioning structure for indirectly positioning the first ferrule relative to the adapter. The first housing is configured such that its movement along the first direction relative to the adapter is restricted, and the movement of the first ferrule along the first direction relative to the first housing is restricted by the flange of the first ferrule, thereby positioning the first ferrule relative to the adapter. Optical connection structure.
2. The predetermined distance at which the tip of the first ferrule and the tip of the second ferrule are separated and facing each other when the first light input / output section and the second light input / output section are optically connected is 0.05 mm or more and 2.0 mm or less. The optical connection structure according to claim 1.
3. The distance from one end of the flange portion of the first ferrule to the tip portion is 2 mm or more and 10 mm or less. The optical connection structure according to claim 1 or claim 2.
4. The invention further comprises a second housing for housing the aforementioned second ferrule, The second ferrule is provided on the side opposite to the tip in the first direction and further has a flange portion that is wider in the second direction than the tip. The flange portion of the second ferrule functions as part of the positioning structure that indirectly positions the second ferrule relative to the adapter. The second housing is configured such that its movement along the first direction relative to the adapter is restricted, and the movement of the second ferrule along the first direction relative to the second housing is restricted by the flange of the second ferrule, thereby positioning the second ferrule relative to the adapter. The optical connection structure according to any one of claims 1 to 3.
5. At least one of the first light input / output section and the second light input / output section is a lens array arranged along the second direction. The optical connection structure according to any one of claims 1 to 4.
6. The lens array is provided in a region recessed into the ferrule from the tip surface of the tip portion, and the tip of the lens array is located further inside the ferrule than the tip surface. The optical connection structure according to claim 5.
7. The lens array has a shape that protrudes from the tip surface of the tip portion to the outside of the ferrule. The optical connection structure according to claim 5.
8. At least one of the third protrusion or third recess and the fourth protrusion or fourth recess of the adapter is configured to be elastically deformable in the second direction. The optical connection structure according to any one of claims 1 to 7.
9. The first side surface of the first ferrule and the first side surface of the second ferrule are provided with a first recess extending along the first direction, and the second side surface of the first ferrule and the second side surface of the second ferrule are provided with a second recess extending along the first direction. The inner surface of the adapter is provided with a third protrusion that can be fitted into the first recess of both the first ferrule and the second ferrule, and a fourth protrusion that can be fitted into the second recess of both the first ferrule and the second ferrule. The first ferrule and the second ferrule are fitted into the adapter such that when the first recesses of both the first and second ferrules are fitted into the third protrusion of the adapter and the second recesses of both the first and second ferrules are fitted into the fourth protrusion of the adapter, the tip of the first ferrule and the tip of the second ferrule face each other at a predetermined distance apart within the adapter, thereby optically connecting the first light input / output section and the second light input / output section. The optical connection structure according to any one of claims 1 to 8.
10. The first housing has a pair of sides facing each other in the second direction, and a column extending in the second direction that connects the pair of sides together. The flange portion of the first ferrule abuts against the column portion, thereby restricting the movement of the first ferrule. The optical connection structure according to any one of claims 1 to 9.
11. The first housing has a pair of first sides facing each other in the second direction and a first column extending in the second direction and connecting the pair of first sides together, The flange portion of the first ferrule abuts against the first column portion, thereby restricting the movement of the first ferrule. The second housing has a pair of second sides facing each other in the second direction, and a second column extending in the second direction and connecting the pair of second sides together. The flange portion of the second ferrule abuts against the second column portion of the second housing, thereby restricting the movement of the second ferrule. The optical connection structure according to claim 4.
12. A first spring is provided, and the flange portion of the first ferrule is biased toward the second ferrule by the first spring. A second spring is provided, and the flange portion of the second ferrule is biased toward the first ferrule by the second spring. The optical connection structure according to claim 4 or claim 11.
13. The movement of the first ferrule toward the second ferrule along the first direction relative to the first housing is restricted by the flange of the first ferrule. The optical connection structure according to any one of claims 1 to 12.
14. The first side surface of the first ferrule is provided with a first positioning portion and a second positioning portion, and a first stepped portion located between the first positioning portion and the second positioning portion. The second side surface of the first ferrule is provided with a third positioning portion and a fourth positioning portion, and a second stepped portion located between the third positioning portion and the fourth positioning portion. The first positioning portion and the second positioning portion are configured to contact the third protrusion or third recess of the adapter, while the first stepped portion is configured not to contact the third protrusion or third recess of the adapter. The third positioning portion and the fourth positioning portion are configured to contact the fourth protrusion or fourth recess of the adapter, while the second stepped portion is configured not to contact the fourth protrusion or fourth recess of the adapter. The optical connection structure according to any one of claims 1 to 13.
15. The first positioning portion and the second positioning portion are separated by a range of 3 mm to 10 mm in the first direction. The optical connection structure according to claim 14.