JP2022174547A - Method for manufacturing optical connector and optical connector - Google Patents

Abstract

To facilitate suppression of optical axis deviation in an optical connector.SOLUTION: A method for manufacturing an optical connector comprises the steps of: irradiating each of a plurality of optical fibers with a laser beam to melt a part thereof and forming a plurality of lensed fibers that is provided with a lens part on respective ends; storing in a ferrule the plurality of lensed fibers on each of which the lens part is formed; and fixing the plurality of lensed fibers in the ferrule. A surface of the lens part is convex toward an outside of the lens part and also has a portion of a curved surface that overlaps a core of the lensed fiber.SELECTED DRAWING: Figure 10

Description

The present disclosure relates to an optical connector manufacturing method and an optical connector.

Patent Document 1 discloses an example of an optical connector for connecting a plurality of optical fibers. This optical connector comprises a ferrule and a lensed fiber. A lensed fiber has an optical fiber and a GRIN lens fusion-spliced to the tip of the optical fiber. Patent Documents 2 to 4 disclose other examples of optical connectors.

JP 2016-184106 A WO2019/097776 JP 2014-178415 A WO2017/149844

In the optical connectors disclosed in Patent Documents 1 and 2, the optical fiber and the lens through which the light from the optical fiber passes are constructed by separate members. Therefore, in order to prevent misalignment of the optical axis, it is necessary to adjust the positions of the optical fiber and the lens when manufacturing or using the optical connector. For example, in the optical connector disclosed in Patent Document 1, it is necessary to adjust the positions of the GRIN lens and the optical fiber when fusion splicing the GRIN lens to the tip of the optical fiber. However, the positional adjustment between the lens and the optical fiber as described above requires high precision and is not easy. Therefore, a technique for easily suppressing optical axis misalignment in an optical connector is desired.

An object of the present disclosure is to provide an optical connector manufacturing method that easily suppresses optical axis deviation, and an optical connector.

A method for manufacturing an optical connector according to the present disclosure includes a step of melting a portion of each of a plurality of optical fibers by irradiating them with laser light to form a plurality of lensed fibers each having a lens portion at each end; The method includes a step of accommodating a plurality of lensed fibers each formed with a lens portion in a ferrule, and a step of fixing the plurality of lensed fibers to the ferrule. The surface of the lens portion has a curved portion that is convex toward the outside of the lens portion and overlaps with the core of the lensed fiber.

An optical connector of the present disclosure includes a plurality of lensed fibers and a ferrule. A ferrule can hold a plurality of lensed fibers. Each lensed fiber has a fiber body extending in the first direction inside the ferrule and a lens portion integrally provided at the end of the fiber body. The surface of the lens portion has a curved portion that is convex toward the outside of the lens portion and intersects with the core of the lensed fiber.

Advantageous Effects of Invention According to the present disclosure, optical axis misalignment in an optical connector can be easily suppressed.

FIG. 1 is a perspective view showing an optical connector according to the first embodiment. FIG. FIG. 2 is a cross-sectional view showing the cross-sectional configuration of the optical connector shown in FIG. 1 along line II-II. FIG. 3 is an enlarged view of area A1 surrounded by a dashed line in FIG. FIG. 4 is a diagram showing the end of the lensed fiber shown in FIG. FIG. 5 is a cross-sectional view of the end of the lensed fiber shown in FIG. 4 cut along the optical axis. FIG. 6 is a diagram showing another example of the lensed fiber. FIG. 7 is a cross-sectional view showing multiple fiber grooves. FIG. 8 is a cross section perpendicular to the optical axis of the lensed fiber, showing an enlarged cross section of one fiber groove. FIG. 9 is a diagram showing the irradiation direction of the laser light with respect to the optical fiber. FIG. 10 is a diagram showing movement of the irradiation position of the laser light. FIG. 11 is a diagram showing how a plurality of optical fibers are cut together. FIG. 12 is a diagram showing irradiation directions of laser light when forming a lensed fiber according to another example. 13 is a diagram showing a cross-sectional configuration of an optical connector according to a first modification of the first embodiment; FIG. FIG. 14 is a diagram showing a cross-sectional configuration of an optical connector according to a second modification of the first embodiment; FIG. 15 is a diagram showing a cross-sectional configuration of an optical connector according to a third modification of the first embodiment; FIG. 16 is a diagram showing a cross-sectional configuration of an optical connector according to the second embodiment. FIG. 17 is an enlarged view of area A2 surrounded by a dashed line in FIG. FIG. 18 is a diagram showing a cross-sectional configuration of an optical connector according to a first modification of the second embodiment; FIG. 19 is a diagram showing a cross-sectional configuration of an optical connector according to a second modification of the second embodiment; FIG. 20 is a diagram showing a cross-sectional configuration of an optical connector according to a third modified example of the second embodiment; FIG. 21 is a diagram showing a cross-sectional configuration of an optical connector according to a fourth modified example of the second embodiment; FIG. 22 is a diagram showing a cross-sectional configuration of an optical connector according to a fifth modification of the second embodiment; FIG. 23 is a diagram showing a cross-sectional configuration of an optical connector according to a sixth modification of the second embodiment; FIG. 24 is a diagram showing a cross-sectional configuration of an optical connector according to a seventh modification of the second embodiment; FIG. 25 is a diagram showing a cross-sectional configuration of an optical connector according to an eighth modification of the second embodiment; FIG. 26 is a diagram showing a cross-sectional configuration of an optical connector according to a ninth modification of the second embodiment;

[Description of Embodiments of the Present Disclosure]
First, the contents of the embodiments of the present disclosure will be listed and described. A method for manufacturing an optical connector according to an embodiment includes a step of melting a portion of each of a plurality of optical fibers by irradiating them with a laser beam to form a plurality of lensed fibers each having a lens portion provided at each end thereof. , a step of accommodating a plurality of lensed fibers each having a lens portion formed therein in a ferrule, and a step of fixing the plurality of lensed fibers to the ferrule. The surface of the lens portion has a curved portion that is convex toward the outside of the lens portion and overlaps with the core of the lensed fiber.

In this manufacturing method, a plurality of lensed fibers having lens portions at each end are formed. Therefore, when manufacturing or using the optical connector, it is not necessary to adjust the positions of the lens portion and the fiber main body provided with the lens portion for optical axis alignment. Therefore, according to the manufacturing method described above, optical axis deviation in the optical connector can be easily suppressed. Further, in the manufacturing method described above, the lens portion is formed by irradiating the laser beam. Therefore, it becomes easier to form a lens portion for an optical fiber having a small diameter, compared to the case where the lens portion is formed by mechanical processing.

As an embodiment, forming the plurality of lensed fibers may include cutting each of the plurality of optical fibers by irradiating with laser light. In this case, the formation of the lens portion and the cutting of the optical fiber can be performed simultaneously by irradiating the laser beam. Therefore, the manufacturing efficiency of the lensed fiber can be improved.

As one embodiment, in the step of forming a plurality of lensed fibers, the plurality of optical fibers are arranged side by side in an arrangement direction that intersects the extending direction of the optical fibers, and the irradiation position of the laser light is moved along the arrangement direction. Accordingly, the lens portions may be collectively formed on each of the plurality of optical fibers. In this case, since the lens portions are collectively formed on each of the plurality of optical fibers, the manufacturing efficiency of the lensed fiber can be improved.

An optical connector according to one embodiment includes a plurality of lensed fibers and a ferrule. A ferrule can hold a plurality of lensed fibers. Each lensed fiber has a fiber body extending in the first direction inside the ferrule and a lens portion integrally provided at the end of the fiber body. The surface of the lens portion has a curved portion that is convex toward the outside of the lens portion and intersects with the core of the lensed fiber.

In this optical connector, each lensed fiber has a lens portion integrally provided at the end of the fiber body. Therefore, when using the optical connector, it is not necessary to adjust the positions of the lens portion and the fiber main body provided with the lens portion for optical axis alignment. Therefore, according to the above optical connector, optical axis deviation in the optical connector can be easily suppressed.

As one embodiment, the lens portion may have a rotationally asymmetric shape with respect to the optical axis of the lensed fiber. In this case, when light is emitted from the lensed fiber, return light due to reflection on the surface of the lens portion is reduced.

As one embodiment, the lens portion may have a rotationally symmetrical shape with respect to the optical axis of the lensed fiber. In this case, the coupling efficiency between the lensed fibers to be optically connected is improved.

As one embodiment, the lens portion may have an outer peripheral portion projecting in a direction away from the optical axis of the lensed fiber from the side surface of the fiber body.

As one embodiment, the curvature radius of the curved surface portion in the cross section along the first direction may be 10 mm or more and 500 mm or less. In this case, the light emitted from the lensed fiber can be appropriately collected by the lens section.

In one embodiment, the ferrule may have a tip face, an aperture, a plurality of fiber grooves, and a lens groove. The opening may be provided on the side opposite to the distal end surface in the first direction. The plurality of fiber grooves may extend along the first direction between the distal end surface and the aperture, and may each be capable of disposing a plurality of fiber bodies. The lens groove may be located closer to the tip surface than the plurality of fiber grooves and may accommodate at least part of the lens portion. In this case, the plurality of fiber grooves and the lens grooves are used to facilitate the positioning of the plurality of lensed fibers and prevent the plurality of lensed fibers from being dislocated.

In one embodiment, the ferrule may include an abutment surface and a tip surface. The abutment surface may be located inside the ferrule, face the lens portion, and intersect the optical axis of the lensed fiber. The tip surface may be located outside the ferrule, face the abutting surface, and intersect the optical axis of the lensed fiber. At least one of the abutment surface and the tip surface may be inclined with respect to a plane perpendicular to the optical axis of the lensed fiber. In this case, the light emitted from the lensed fiber passes through the abutment surface and the tip surface. At least one of the abutment surface and the tip surface is inclined with respect to the plane perpendicular to the optical axis, so return light due to reflection is reduced.

In one embodiment, the ferrule may have a window facing at least a portion of the region in which the plurality of fiber grooves are formed. The optical connector may further include a pressing portion arranged in the window portion and pressing the plurality of lensed fibers toward the plurality of fiber grooves. In this case, the plurality of lensed fibers are pressed toward the plurality of fiber grooves by the pressing portion. As a result, the lensed fibers are prevented from being lifted from the fiber grooves, thereby preventing misalignment of the plurality of lensed fibers.

An embodiment may further include an adhesive that secures the plurality of lensed fibers to the ferrule. The adhesive may be provided at a position intersecting the optical axis of each of the plurality of lensed fibers. The refractive index of the adhesive may be smaller than the refractive index of each core of the plurality of lensed fibers. In this case, the adhesive more reliably prevents misalignment of the plurality of lensed fibers. Also, the refractive index of the adhesive is smaller than the refractive index of each core of the plurality of lensed fibers. Therefore, the beam diameter of the light emitted from each core is suppressed from increasing inside the adhesive.

[Details of the embodiment of the present disclosure]
A specific example of an optical connector and an optical connector manufacturing method according to an embodiment of the present disclosure will be described below with reference to the drawings. The present invention is not limited to these examples, but is indicated by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

<First embodiment>
The overall configuration of the optical connector 1 will be described with reference to FIGS. 1 to 3. FIG. FIG. 1 is a perspective view showing an optical connector 1 according to the first embodiment. FIG. 2 is a diagram showing a cross-sectional configuration of the optical connector 1. As shown in FIG. FIG. 2 shows a cross section of the optical connector 1 taken along line II-II shown in FIG. FIG. 3 is an enlarged view of area A1 surrounded by a dashed line in FIG. FIG. 3 shows the peripheral configuration of the lens portion 12 that the optical connector 1 has. For convenience of explanation, the longitudinal direction of the optical connector 1 is defined as the direction X (first direction), the lateral direction of the optical connector 1 is defined as the direction Y (second direction), and the thickness direction of the optical connector 1 is defined as the direction Z (third direction). ). Direction X, direction Y and direction Z intersect each other. In this embodiment, direction X, direction Y and direction Z are orthogonal to each other. The optical connector 1 is, for example, a connector for optically connecting a plurality of lensed fibers 10 to respective lensed fibers of another optical connector. The optical connector 1 includes a plurality of lensed fibers 10 and ferrules 20, as shown in FIG.

Each lensed fiber 10 carries an optical signal. Each lensed fiber 10 extends along the direction X inside the ferrule 20 . A plurality of lensed fibers 10 are arranged along the Y direction. In this embodiment, the optical connector 1 has 12 lensed fibers 10 . The number of lensed fibers 10 included in the optical connector 1 is not limited. The number of lensed fibers 10 included in the optical connector 1 may be 4, 8, or 24. The plurality of lensed fibers 10 may be collectively coated with resin. The resin coating the plurality of lensed fibers 10 may be an ultraviolet curable resin.

Here, the configuration of the lensed fiber 10 will be described with reference to FIGS. 4 and 5. FIG. FIG. 4 is a diagram showing the end of the lensed fiber 10 shown in FIG. FIG. 5 is a cross-sectional view of the end of the lensed fiber 10 shown in FIG. 4 cut along the optical axis S. As shown in FIG. The lensed fiber 10 has a fiber main body 11 and a lens portion 12, as shown in FIGS. The lensed fiber 10 is formed from an optical fiber. Hereinafter, an optical fiber that is a material of the lensed fiber 10 and does not have the lens portion 12 formed thereon is simply referred to as an "optical fiber", and an optical fiber that has the lens portion 12 formed therein (lensed fiber 10 ) are distinguished from each other. The lensed fiber 10 may be formed from a glass optical fiber.

The fiber body 11 extends in the X direction. The lens portion 12 is provided integrally with the fiber body 11 at the end of the fiber body 11 . The fact that the lens portion 12 is provided integrally with the fiber main body 11 means that the lens portion 12 is continuously connected to the fiber main body 11 without a break. The fiber main body 11 and the lens portion 12 respectively have a core 13 and a clad 14 surrounding the core 13, as shown in FIG. The core 13 and the clad 14 are made of, for example, pure silica (SiO2) glass, or silica glass doped with germanium or fluorine.

The lens portion 12 has an outer peripheral portion 12 a that protrudes from the side surface 11 a of the fiber main body 11 in a direction away from the optical axis S of the lensed fiber 10 . The optical axis S extends along the direction X in this embodiment. The outer peripheral portion 12 a is formed continuously so as to surround the optical axis S of the lens portion 12 . Although details will be described later, the lensed fiber 10 is formed by irradiating an optical fiber with a laser. Part of the optical fiber is melted by heat generated by the laser irradiation, and the lens portion 12 having the outer peripheral portion 12a is formed. The outer peripheral portion 12a is located within 200 μm from the tip of the lens portion 12 in the direction X, for example. The diameter of the lens portion 12 when viewing the lensed fiber 10 from the direction X is larger than the diameter of the fiber main body 11 . The lens portion 12 has a rotationally asymmetric shape with respect to the optical axis S. As shown in FIG. In the present embodiment, a portion P1 of the outer peripheral portion 12a located on the upper side of the paper surface of FIG. 4 is located closer to the tip of the lensed fiber 10 than a portion P2 of the outer peripheral portion 12a located on the lower side of the paper surface. ing.

In the lens portion 12, the diameter of the core 13 differs in the direction X, as shown in FIG. Specifically, the diameter of the core 13 gradually increases toward the tip side of the lensed fiber 10 . Surface 15 of lens portion 12 has a curved portion 16 . The curved portion 16 is a portion that intersects with the core 13 . The core 13 is made of, for example, a material with a higher refractive index than the clad 14 . The light entering the core 13 travels through the core 13 while being totally reflected at the interface between the core 13 and the clad 14 . In the case of the lensed fiber 10 that emits light, the light traveling inside the core 13 is emitted from the curved surface portion 16 to the outside of the lensed fiber 10 .

The curved surface portion 16 is curved so as to be convex toward the outside of the lens portion 12 . Thereby, the lens part 12 can function as a condensing lens for the light emitted from the lensed fiber 10 . A curvature radius of the curved surface portion 16 in a cross section along the direction X may be 10 mm or more and 500 mm or less. In this embodiment, the curved portion 16 has a rotationally asymmetric shape with respect to the optical axis S. As shown in FIG. Therefore, when the curved surface portion 16 is cut at a plurality of different step surfaces along the direction X, the radius of curvature of the curved surface portion 16 in each cross section can be different.

As shown in FIG. 4, a plurality of fine particles 18 are attached to a region of the side surface 11a near the lens portion 12. As shown in FIG. As described above, the lensed fiber 10 is formed by irradiating an optical fiber with a laser. During the laser irradiation, part of the material forming the optical fiber evaporates. After that, the evaporated material is cooled and adheres to the side surface 11a as fine particles 18. FIG. The fine particles 18 contain at least one material of the core 13 and the clad 14 . The diameter of the fine particles 18 is, for example, 10 nm or more and 500 nm or less. The microparticles 18 can be observed as cloudy when using a microscope.

The shape of the lensed fiber is not limited to the shapes described above. FIG. 6 is a diagram showing another example of the lensed fiber. The lensed fiber 110 shown in FIG. 6 has a lens portion 112 . Although the lens portion 12 described above has a rotationally asymmetric shape with respect to the optical axis S, the lens portion 112 has a rotationally symmetrical shape with respect to the optical axis S. As shown in FIG. As shown in FIG. 6, the lens portion 112 has an outer peripheral portion 112a that protrudes in a direction away from the optical axis S from the side surface 11a. The outer peripheral portion 112 a is formed continuously so as to surround the optical axis S of the lens portion 112 . The diameter of the lens portion 112 when viewing the lensed fiber 10 from the direction X is larger than the diameter of the fiber main body 11 . Lens portion 112 has a surface 115 . The surface 115 is a curved surface that is convex outward from the lens portion 12 and has a rotationally symmetrical shape with respect to the optical axis S. As shown in FIG.

In the following description, unless otherwise specified, the case where the optical connector 1 includes a plurality of lensed fibers 10 will be described as an example. 110 may be provided.

Returning from FIG. 1 to FIG. 3, the description of the overall configuration of the optical connector 1 will be continued. A ferrule 20 holds the ends of the plurality of lensed fibers 10 . The ferrule 20 has a substantially rectangular parallelepiped appearance. The ferrule 20 has a front end surface 21, a rear end surface 22, side surfaces 23 and 24, an upper surface 25 and a lower surface 26, as shown in FIG. Hereinafter, in the direction X, the direction from the rear end surface 22 to the front end surface 21 is defined as the front, and the direction from the front end surface 21 to the rear end surface 22 is defined as the rear. In addition, in the direction Z, the direction from the lower surface 26 to the upper surface 25 is defined as upward, and the direction from the upper surface 25 to the lower surface 26 is defined as downward. The ferrule 20, as shown in FIG. 2, has a housing portion 30 capable of housing the end portions of the plurality of lensed fibers 10. As shown in FIG. The accommodation portion 30 is a space inside the ferrule 20 .

The tip surface 21 is a surface positioned at the front end of the optical connector 1 . The tip surface 21 crosses the optical axis S of the lensed fiber 10 . The tip surface 21 is inclined with respect to a plane perpendicular to the direction X (YZ plane). The inclination angle of the tip surface 21 may be 20° or less, or may be 8°. The tip surface 21 has a plurality of lens portions 21a. The plurality of lens portions 21a are arranged in a line along the direction Y as shown in FIG. Each lens portion 21 a is formed at a position that intersects the optical axis S of each corresponding lensed fiber 10 and is optically coupled to each lensed fiber 10 . The optical axis of each lens portion 21a may coincide with the optical axis S of each lensed fiber 10 when viewed from the direction X. Each lens part 21a collimates the light emitted from each lensed fiber 10, for example. The collimated light may enter an optical connector to which the optical connector 1 is connected.

A pair of guide holes 21b are formed in the tip surface 21 . The pair of guide holes 21b are positioned so as to sandwich the plurality of lens portions 21a in the Y direction. Each guide hole 21b extends in the X direction. In this embodiment, each guide hole 21b is a non-through hole having a bottom surface. Each guide hole 21b is open at the tip surface 21. As shown in FIG. The diameter of each guide hole 21b is larger than the diameter of the lens portion 21a. One end of a guide pin (not shown) having, for example, a cylindrical outer shape is inserted into each guide hole 21b. The other end of the guide pin is inserted into each guide hole formed in the ferrule of the mating optical connector. The pair of guide holes 21b enables positioning of the optical connector 1 using guide pins.

The rear end surface 22 is a surface positioned at the rear end of the optical connector 1 . The rear end face 22 has openings 22a into which a plurality of lensed fibers 10 can be inserted, as shown in FIG. The opening 22a is connected with the housing portion 30 . The opening 22a is located on the opposite side of the tip surface 21 in the X direction. A plurality of lensed fibers 10 are housed inside the housing portion 30 through the openings 22a. Each side surface 23, 24 is a surface extending in directions X and Z, as shown in FIG. The side surfaces 23 and 24 face each other in the Y direction.

The upper surface 25 is a surface extending in the X and Y directions. The ferrule 20 has a window portion 25a that opens in the upper surface 25. As shown in FIG. The window portion 25 a is a through hole formed from the upper surface 25 toward the housing portion 30 . The window portion 25 a communicates the external space of the optical connector 1 and the housing portion 30 . The window portion 25a has a rectangular shape when viewed from the direction X. As shown in FIG. The shape of the window portion 25a is not limited. The window portion 25a may have a circular shape or a polygonal shape when viewed from the direction X. The lower surface 26 is a surface extending in the X direction and the Y direction. The lower surface 26 faces the upper surface 25 in the Z direction.

Materials constituting the ferrule 20 are PPS (polyphenylene sulfide), PEI (polyetherimide), PBT (polybutylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), and PES (polyether sulfone). , PA (polyamide), or COP (cycloolefin polymer).

The housing portion 30 is a space capable of housing the end portions of the plurality of lensed fibers 10 . The housing portion 30 is defined by an upper inner surface 31, a lower inner surface 32, a step surface 33, a fiber support surface 34 and an abutment surface 37, as shown in FIG. The upper inner surface 31 is a surface extending along the X and Y directions. The rear end of the upper inner surface 31 in the direction X is connected to the rear end surface 22, and the front end of the upper inner surface 31 is connected to the inner surface of the window portion 25a.

The lower inner surface 32 is a surface extending along the X direction and the Y direction, and faces the upper inner surface 31 in the Z direction. A rear end of the lower inner surface 32 in the direction X is connected to the rear end surface 22 , and a front end of the lower inner surface 32 is connected to the stepped surface 33 . The step surface 33 is a surface extending along the Y direction and the Z direction. The lower end of the stepped surface 33 in direction Z is connected to the lower inner surface 32 and the upper end of the stepped surface 33 is connected to the fiber support surface 34 . The fiber support surface 34 is a surface extending in the X and Y directions. The rear end of the fiber support surface 34 in the direction X is connected with the stepped surface 33 , and the front end of the fiber support surface 34 is connected with the abutment surface 37 . The abutment surface 37 is a surface that is inclined with respect to the YZ plane. The inclination angle of the abutting surface 37 may be 20° or less, or may be 8°. The abutment surface 37 is a surface facing the tip end surface 21, as shown in FIG. The abutment surface 37 faces the lens portion 12 and intersects the optical axis S of the lensed fiber 10 .

A plurality of fiber grooves 35 and lens grooves 36 are formed in the fiber support surface 34 . Here, referring to FIGS. 7 and 8 together, the configurations of the plurality of fiber grooves 35 and lens grooves 36 will be described. FIG. 7 is a cross-sectional view showing multiple fiber grooves 35 . FIG. 8 is an enlarged cross-sectional view of one fiber groove 35, showing region B surrounded by a dashed line in FIG. The cross sections shown in FIGS. 7 and 8 are cross sections obtained by cutting the ferrule 20 along the YZ plane. In FIGS. 7 and 8, for convenience of explanation, illustration of some of the multiple configurations included in the optical connector 1 is omitted.

Each fiber groove 35 extends along direction X in fiber support surface 34 . The front end of each fiber groove 35 connects with a lens groove 36, as shown in FIG. The rear end of each fiber groove 35 is connected to the step surface 33 as shown in FIG. A plurality of fiber grooves 35 are aligned in the direction Y as shown in FIG. A plurality of lensed fibers 10 are arranged in the plurality of fiber grooves 35, respectively. The plurality of fiber grooves 35 face the plurality of lens portions 21a in the direction X, respectively. At least part of the region of the fiber support surface 34 where the plurality of fiber grooves 35 are formed faces the window 25a in the Z direction.

Each fiber groove 35 is a groove recessed from the fiber support surface 34 toward the lower surface 26, as shown in FIG. Each fiber groove 35 is a V-groove with a pointed bottom. As shown in FIG. 8, a pair of inner walls 35a defining each fiber groove 35 are slanted with respect to the fiber support surface 34 and are connected at the bottom of the fiber groove 35. As shown in FIG. The width of the fiber groove 35 in the direction Y becomes smaller toward the bottom. Thereby, the lensed fiber 10 arranged in the fiber groove 35 is held so as to be sandwiched between the pair of inner walls 35a of the fiber groove 35, and positional displacement in the direction Y is prevented. The shape of the fiber groove 35 is not limited to the V-groove, and may be, for example, a U-groove with a rounded bottom, or a rectangular groove having a bottom surface extending along the X and Y directions. may

As shown in FIG. 3, the lens grooves 36 are located closer to the tip surface 21 than the plurality of fiber grooves 35 are. The lens groove 36 extends along the Y direction. The lens groove 36 is a groove recessed from the fiber support surface 34 toward the lower surface 26 . The lens groove 36 is a rectangular groove having a bottom surface 36a extending along the X and Y directions. The shape of the lens groove 36 is not limited to a rectangular groove, and may be, for example, a V groove with a sharp bottom or a U groove with a rounded bottom. The lens groove 36 accommodates at least a portion of each lens portion 12, as shown in FIG. In this embodiment, part of the outer peripheral portion 12a is accommodated. The depth of lens groove 36 in direction Z is greater than the depth of each fiber groove 35 .

The relationship between the diameter of the lensed fiber 10 and the width of the fiber groove 35 will be described with reference to FIG. FIG. 8 shows a virtual circle C indicated by a dashed line. A virtual circle C indicates the outer edge shape of the lens portion 12 when the lensed fiber 10 is viewed from the direction X. As shown in FIG. FIG. 8 shows the relationship between the diameter D1 of the fiber main body 11, the diameter D2 of the virtual circle C, and the width W1 of the fiber groove 35. As shown in FIG. The width W1 is the maximum width in the direction Y between the pair of inner walls 35a. The width W1 may be 0.10 mm or more and 0.25 mm or less. The diameter D1 is the diameter of the YZ section of the fiber body 11 . The diameter D1 may be 0.08 mm or more and 0.13 mm or less. A diameter D2 is the diameter of the virtual circle C. The diameter D2 may be, for example, 0.10 mm or more and 0.15 mm or less. As shown in FIG. 8, width W1 is larger than diameter D1 and smaller than diameter D2.

The optical connector 1 has a pressing portion 40 as shown in FIG. The pressing portion 40 is arranged in the window portion 25 a and presses the plurality of lensed fibers 10 toward the plurality of fiber grooves 35 . In this embodiment, the pressing portion 40 has a rectangular parallelepiped shape. The shape of the pressing portion 40 is not limited as long as it can be arranged in the window portion 25a. The pressing portion 40 has an upper surface 41 and a lower surface 42 facing each other in the Z direction. In this embodiment, the lower surface 42 is in direct contact with the plurality of lensed fibers 10, as shown in FIG. The lower surface 42 does not necessarily have to be in direct contact with the plurality of lensed fibers 10 , and an adhesive 50 may be interposed between the lower surface 42 and the plurality of lensed fibers 10 . In this embodiment, the entire pressing portion 40 is accommodated inside the window portion 25a, but a portion of the pressing portion 40 may be positioned outside the window portion 25a. For example, top surface 41 may be positioned above top surface 25 . The pressing portion 40 may be made of a material that transmits ultraviolet rays.

An adhesive 50 for fixing the plurality of lensed fibers 10 to the ferrule 20 is arranged in the window portion 25 a and the accommodation portion 30 . The adhesive 50 may be an ultraviolet curable adhesive. The adhesive 50 is injected into the housing portion 30 through the window portion 25a, for example. The adhesive 50 is positioned between the lens portion 12 and the abutment surface 37, as shown in FIG. The adhesive 50 crosses the optical axis S of the lensed fiber 10 . The adhesive 50 may be located in the gap between each lensed fiber 10 and each fiber groove 35 .

The refractive index of the adhesive 50 may be smaller than that of the core 13 . When the refractive index of the adhesive 50 is smaller than the refractive index of the core 13 , the beam diameter of the light emitted from the core 13 is suppressed from increasing inside the adhesive 50 . The refractive index of the adhesive 50 may be greater than that of the core 13 . When the refractive index of the adhesive 50 is higher than that of the core 13 , the beam diameter of the light emitted from the core 13 increases as the light travels inside the adhesive 50 . However, since the light passes through the lens portion 21a after passing through the adhesive 50, further increase in the beam diameter is suppressed.

Next, a method for manufacturing the optical connector 1 will be described. First, a plurality of lensed fibers 10 are formed. Here, the process of forming the lensed fiber 10 will be described with reference to FIGS. 9 to 11. FIG. FIG. 9 is a diagram showing the irradiation direction of the laser light L with respect to the optical fiber 2. As shown in FIG. In FIG. 9, the laser light L at the time when the irradiation of the laser light L is started is indicated by a solid line. 10A and 10B are diagrams showing movement of the irradiation position of the laser light L. FIG. In FIG. 10, the laser light L at the time when the irradiation of the laser light L is started is indicated by a broken line, and the laser light L at the time when the irradiation of the laser light L is finished is indicated by a solid line. FIG. 11 is a diagram showing how a plurality of optical fibers 2 are cut together. In addition, the process of forming the lensed fiber 110 will also be described with reference to FIG. 12 . FIG. 12 is a diagram showing the irradiation direction of the laser light L when forming the lensed fiber 110. As shown in FIG. In FIG. 12, the solid line shows the laser beam L at the time when the irradiation of the laser beam L is finished.

First, as shown in FIG. 9, an optical fiber 2 is prepared. Next, the optical fiber 2 is irradiated with laser light L, and the optical fiber 2 is cut by heat. In this embodiment, the laser light L is applied in a direction perpendicular to the extending direction of the optical fiber 2 . The irradiation direction of the laser light L does not necessarily have to be perpendicular to the extending direction of the optical fiber 2, and can be appropriately adjusted so that the lens portion 12 is formed into a desired shape. A light source (irradiation light source) for irradiating the laser light L may be a carbon dioxide laser or a YAG laser. The wavelength of the laser light L may be 0.3 μm or more and 15 μm or less. The output of the laser light L may be 5 W or more and 80 W or less.

A portion of the optical fiber 2 is melted by the heat given by the irradiation of the laser light L. FIG. When the laser irradiation ends, the temperature of the melted portion drops. The melted portion re-hardens as the temperature drops to form the lens portion 12 . In this embodiment, the cutting of the optical fiber 2 and the formation of the lens portion 12 are simultaneously performed by the irradiation of the laser light L. FIG. By melting the optical fiber 2 , the material forming the core 13 is diffused inside the optical fiber 2 . Therefore, as shown in FIG. 5, the diameter of the core 13 in the lens portion 12 is larger than the diameter of the core 13 in the fiber main body 11 .

As shown in FIG. 9, when the laser light L is irradiated in the direction perpendicular to the extending direction of the optical fiber 2, the portion of the optical fiber 2 near the irradiation light source is easily melted by the heat of the laser light L. Portions far from the irradiation light source are difficult to melt. Therefore, as shown in FIG. 10, the portion P4 of the lens portion 12 far from the irradiation light source is projected toward the tip of the lensed fiber 10 (to the left in FIG. 10) more than the portion P3 close to the irradiation light source. formed in Therefore, the lens portion 12 has a rotationally asymmetric shape with respect to the optical axis S of the lensed fiber 10 .

When the laser beam L is irradiated, the irradiation position of the laser beam L may be moved along the extending direction of the optical fiber 2, as shown in FIG. In this embodiment, the irradiation position of the laser beam L is slightly moved leftward on the paper surface as indicated by arrow E in FIG. 10 . The moving distance and moving direction of the irradiation position of the laser light L may be appropriately determined according to the intensity of the laser light L, the diameter of the optical fiber, or the desired shape of the lens portion 12 .

Next, referring to FIG. 11, a method of collectively forming the lens portions 12 on each of the plurality of optical fibers 2 will be described. First, as shown in FIG. 11, a plurality of optical fibers 2 are arranged side by side in a direction (arrangement direction) intersecting the extending direction of each optical fiber 2 . A plurality of optical fibers 2 extend parallel to each other. Next, laser light L is applied to each optical fiber 2 . At this time, the irradiation position of the laser light L is moved along the virtual line T shown in FIG. The virtual line T overlaps the plurality of optical fibers 2 and extends along the arrangement direction. A laser beam L is irradiated along a virtual line T so as to traverse the plurality of optical fibers 2 . As a result, the plurality of optical fibers 2 are collectively cut, and the lens portions 12 are collectively formed on each of the plurality of optical fibers 2 . In other words, a plurality of lensed fibers 10 are collectively formed. The laser light L may be irradiated so as to reciprocate on the virtual line T multiple times. In this case, each optical fiber 2 is irradiated with the laser light L multiple times.

The method of forming each lensed fiber 10 is not limited to the method described above. For example, the cutting of the optical fiber 2 and the formation of the lens portion 12 may be performed at different timings. Specifically, after cutting the optical fiber 2 by irradiating it with a laser beam, the lens portion 12 may be formed by further irradiating the end surface of the cut optical fiber 2 with a laser beam. The intensity of the laser light for cutting the optical fiber 2 may be different from the intensity of the laser light for forming the lens portion 12 . The optical fiber 2 does not necessarily have to be cut by laser light, and may be cut mechanically. When the optical fiber 2 is cut mechanically, the lens portion 12 may be formed by irradiating the cut end face of the optical fiber 2 with a laser beam.

Here, the process of forming the lensed fiber 110 will also be described with reference to FIG. The lensed fiber 110 has a lens portion 112 that is rotationally symmetrical with respect to the optical axis S, as described above with reference to FIG. Like the lensed fiber 10, the lensed fiber 110 is formed by irradiating an optical fiber with laser light L. As shown in FIG.

In the step of forming the lensed fiber 110 , the laser light L is irradiated in a direction inclined with respect to a virtual plane U perpendicular to the extending direction of the optical fiber that is the material of the lensed fiber 110 . At this time, the laser light L is irradiated from a position that does not overlap the formed lensed fiber 110 in the direction along the virtual plane U (in FIG. 12, the position on the left side of the virtual plane U). As a result, even a portion of the optical fiber far from the irradiation light source (portion P14 in FIG. 12) is likely to be irradiated with the laser light L. Therefore, the end portion of the optical fiber that becomes the lens portion 112 is irradiated with the laser light L in a well-balanced manner, and the lens portion 112 can have a rotationally symmetrical shape with respect to the optical axis S. The inclination angle of the irradiation direction with respect to the virtual plane U may be appropriately determined according to the intensity of the laser light L or the diameter of the optical fiber.

After the step of forming the plurality of lensed fibers 10 is completed, the plurality of lensed fibers 10 are accommodated in the ferrule 20 . Specifically, as shown in FIG. 2, the end portions of the plurality of lensed fibers 10 are housed inside the housing portion 30 through the openings 22a. At this time, a plurality of fiber main bodies 11 are arranged in each of the plurality of fiber grooves 35 .

Subsequently, the adhesive 50 is injected into the housing portion 30 through the window portion 25 a to fix the plurality of lensed fibers 10 to the ferrule 20 with the adhesive 50 . At this time, before the adhesive 50 hardens, the pressing portion 40 is arranged in the window portion 25 a to press the plurality of lensed fibers 10 toward the plurality of fiber grooves 35 . Thus, the manufacturing process of the optical connector 1 is completed.

As described above, in the method for manufacturing the optical connector 1 according to the present embodiment, a plurality of lensed fibers 10 each having a lens portion 12 provided at each end are formed. Therefore, when the optical connector 1 is manufactured or used, there is no need to adjust the positions of the lens portion 12 and the fiber main body 11 provided with the lens portion 12 for optical axis alignment. Therefore, according to the manufacturing method described above, optical axis deviation in the optical connector 1 can be easily suppressed. Further, in the manufacturing method described above, the lens portion 12 is formed by irradiating the laser light L. As shown in FIG. Therefore, it becomes easier to form the lens portion 12 for the optical fiber 2 having a small diameter, compared to the case where the lens portion 12 is formed by mechanical processing.

In the above-described embodiment, the step of forming the plurality of lensed fibers 10 may include the step of cutting each of the plurality of optical fibers 2 by irradiating the laser beam L thereon. In this case, the formation of the lens portion 12 and the cutting of the optical fiber 2 can be performed simultaneously by irradiation with the laser beam L. FIG. Therefore, the manufacturing efficiency of the lensed fiber 10 can be improved.

In the above embodiment, in the step of forming the plurality of lensed fibers 10, the plurality of optical fibers 2 are arranged in the arrangement direction that intersects the extending direction of the optical fibers 2, and the irradiation position of the laser light L is arranged in the arrangement direction. The lens portions 12 may be collectively formed on each of the plurality of optical fibers 2 by moving along. In this case, since the lens portions 12 are collectively formed on each of the plurality of optical fibers 2, the manufacturing efficiency of the lensed fiber 10 can be improved.

In the optical connector 1 according to this embodiment, each lensed fiber 10 has a lens portion 12 integrally provided at the end portion of the fiber main body 11 . Therefore, when using the optical connector 1, it is not necessary to adjust the positions of the lens portion 12 and the fiber main body 11 provided with the lens portion 12 in order to align the optical axes. Therefore, according to the optical connector 1 according to the present embodiment, optical axis deviation in the optical connector 1 is easily suppressed.

In the above embodiment, the lens portion 12 may have a rotationally asymmetric shape with respect to the optical axis S of the lensed fiber 10 . In this case, when light is emitted from the lensed fiber 10, return light due to reflection on the surface of the lens portion 12 is reduced.

In the above embodiment, the lens portion 112 may have a shape that is rotationally symmetrical with respect to the optical axis S of the lensed fiber 110 . In this case, the coupling efficiency between the lensed fibers 110 to be optically connected is improved.

In the above-described embodiment, the lens portion 12 may have an outer peripheral portion 12a that protrudes from the side surface 11a of the fiber main body 11 in a direction away from the optical axis S of the lensed fiber 10 .

In the above embodiment, the curvature radius of the curved surface portion 16 in the cross section along the direction X may be 10 mm or more and 500 mm or less. In this case, the light emitted from the lensed fiber 10 can be appropriately condensed by the lens portion 12 .

In the above embodiment, the ferrule 20 may have the tip surface 21, the opening 22a, the plurality of fiber grooves 35, and the lens grooves . The opening 22a may be provided on the opposite side of the tip surface 21 in the direction X. The plurality of fiber grooves 35 may extend along the direction X between the tip surface 21 and the opening 22a, and allow the plurality of fiber bodies 11 to be arranged respectively. The lens groove 36 may be located closer to the tip surface 21 than the plurality of fiber grooves 35 and may accommodate at least part of the lens portion 12 . In this case, the plurality of fiber grooves 35 and the lens grooves 36 are used to facilitate the positioning of the plurality of lensed fibers 10 and prevent the plurality of lensed fibers 10 from being dislocated.

In the embodiment described above, the ferrule 20 may include the abutment surface 37 and the tip surface 21 . The abutment surface 37 may be located inside the ferrule 20 , face the lens portion 12 , and intersect the optical axis S of the lensed fiber 10 . The tip surface 21 may be located outside the ferrule 20 , face the abutment surface 37 , and intersect the optical axis S of the lensed fiber 10 . At least one of the abutment surface 37 and the tip surface 21 may be inclined with respect to a plane perpendicular to the optical axis S of the lensed fiber 10 . In this case, light emitted from the lensed fiber 10 passes through the abutment surface 37 and the tip surface 21 . At least one of the abutment surface 37 and the tip surface 21 is inclined with respect to a plane (YZ plane) perpendicular to the optical axis S, so that return light due to reflection is reduced.

In the above embodiment, the ferrule 20 may have a window portion 25a facing at least part of the region in which the plurality of fiber grooves 35 are formed. The optical connector 1 may further include a pressing portion 40 that is arranged in the window portion 25 a and presses the plurality of lensed fibers 10 toward the plurality of fiber grooves 35 . In this case, the plurality of lensed fibers 10 are pressed toward the plurality of fiber grooves 35 by the pressing portion 40 . Therefore, since the lensed fiber 10 is suppressed from being lifted from the fiber groove 35, positional displacement of the plurality of lensed fibers 10 is prevented.

In the above embodiment, the optical connector 1 may further include an adhesive 50 that fixes the multiple lensed fibers 10 to the ferrule 20 . The adhesive 50 may be provided at a position that intersects the optical axis S of each of the plurality of lensed fibers 10 . The refractive index of the adhesive 50 may be smaller than the refractive index of each core 13 of the plurality of lensed fibers 10 . In this case, the adhesive 50 more reliably prevents misalignment of the plurality of lensed fibers 10 . Also, the refractive index of the adhesive 50 is smaller than the refractive index of each core 13 of the plurality of lensed fibers 10 . Therefore, the beam diameter of the light emitted from each core 13 is suppressed from increasing inside the adhesive 50 .

First to third modifications of the optical connector 1 described above will be described with reference to FIGS. 13 to 15 . In the description of the optical connectors according to the respective modifications, differences from the optical connector 1 of the above-described first embodiment will be mainly described, and descriptions of common points may be omitted.

FIG. 13 is a diagram showing a cross-sectional configuration of an optical connector 100 according to a first modified example. FIG. 13 shows the configuration around the lens portion 12 in the XZ cross section of the optical connector 100 . The optical connector 100 includes multiple lensed fibers 10 and ferrules 120 . The ferrule 120 has a tip surface 121 and an abutment surface 137 . The tip surface 121 differs from the tip surface 21 in that it extends parallel to the YZ plane and that it does not have a lens portion. The tip surface 121 may be coated with a refractive index matching agent. The abutment surface 137 differs from the abutment surface 37 in that it extends parallel to the YZ plane. Ferrule 120 has a fiber support surface 134 . Fiber support surface 134 is common to fiber support surface 34 in that it includes a plurality of fiber grooves 135, but differs from fiber support surface 34 in that it does not include lens grooves. Each fiber groove 135 extends along the X direction. The front end of each fiber groove 135 connects to the bottom end of the abutment surface 137 . According to this first modification, the steps of forming a lens portion on the tip surface 121, tilting the tip surface 121 by polishing, and forming a lens groove are not required. 100 can be achieved. Further, when the tip end face 121 is coated with a refractive index matching agent, the reflection of the light emitted from the lensed fiber 10 at the tip end face 121 is suppressed.

FIG. 14 is a diagram showing a cross-sectional configuration of an optical connector 200 according to a second modified example. FIG. 14 shows the peripheral configuration of the lens portion 12 in the XZ cross section of the optical connector 200. As shown in FIG. The optical connector 200 includes multiple lensed fibers 10 and ferrules 220 . Ferrule 220 has a tip surface 221 and an abutment surface 237 . The tip surface 221 differs from the tip surface 21 in that it extends parallel to the YZ plane and that it does not have a lens portion. The tip surface 221 may be coated with a refractive index matching agent. The abutment surface 237 differs from the abutment surface 37 in that it extends parallel to the YZ plane. According to the second modification, the step of forming a lens portion on the tip end surface 221 and the step of tilting the tip end surface 221 by polishing are not required, so the optical connector 200 can be realized by a simple method. Further, when the tip surface 221 is coated with a refractive index matching agent, the reflection of the light emitted from the lensed fiber 10 on the tip surface 221 is suppressed.

FIG. 15 is a diagram showing a cross-sectional configuration of an optical connector 300 according to a third modified example. 15 shows the configuration around the lens portion 12 in the XZ cross section of the optical connector 300. As shown in FIG. The optical connector 300 includes multiple lensed fibers 10 and ferrules 320 . Ferrule 320 has a tip surface 321 and an abutting surface 337 . The tip surface 321 and the abutment surface 337 differ from the tip surface 21 and the abutment surface 37 in that they extend parallel to the YZ plane. Ferrule 320 has a fiber support surface 334 . Fiber support surface 334 is similar to fiber support surface 34 in that it includes a plurality of fiber grooves 335, but differs from fiber support surface 34 in that it does not include lens grooves. Each fiber groove 335 extends along the X direction. The front end of each fiber groove 335 connects to the lower end of an abutment surface 337 . According to the third modification, the step of tilting the tip surface 321 by polishing and the step of forming lens grooves are not required, so the optical connector 300 can be realized by a simple method.

<Second embodiment>
A second embodiment of the optical connector will be described with reference to FIGS. 16 and 17. FIG. FIG. 16 is a diagram showing a cross-sectional configuration of an optical connector 400 according to the second embodiment. FIG. 16 shows an XZ cross section of the optical connector 400. As shown in FIG. FIG. 17 is an enlarged view of area A2 surrounded by a dashed line in FIG. FIG. 17 shows the peripheral configuration of the lens portion 12 that the optical connector 400 has. In the description of the optical connector 400 of the second embodiment, mainly the points of difference from the optical connector 1 of the first embodiment described above will be mainly described, and descriptions of common points may be omitted.

The optical connector 400 includes multiple lensed fibers 10 and ferrules 420 . The optical connector 400 may include multiple lensed fibers 110 instead of multiple lensed fibers 10 . The optical connector 400 differs from the optical connector 1 in that it does not have a pressing portion. Optical connector 400 also differs from optical connector 1 in that ferrule 420 does not have a plurality of fiber grooves 35 and lens grooves 36 . Although only one lensed fiber 10 is shown in FIGS. 16 and 17, a plurality of lensed fibers 10 are actually arranged along the Y direction. A ferrule 420 holds the ends of the plurality of lensed fibers 10 . The ferrule 420 has a front end surface 421, a rear end surface 422, an upper surface 425 and a lower surface 426, as shown in FIG. The ferrule 420 has, as shown in FIG. 16, a housing portion 430 capable of housing the end portions of a plurality of lensed fibers 10 and a plurality of housing holes 435 . Although only one receiving hole 435 is shown in FIGS. 16 and 17, a plurality of receiving holes 435 are actually arranged along the Y direction.

The tip surface 421 is a surface positioned at the front end of the optical connector 400 . The tip surface 421 extends parallel to the YZ plane. A plurality of receiving holes 435 are formed in the distal end surface 421 . The rear end surface 422 is a surface positioned at the rear end of the optical connector 400 . The rear end face 422 has openings 422a into which a plurality of lensed fibers 10 can be inserted, as shown in FIG. The opening 422a is connected with the housing portion 430 .

The top surface 425 is a surface extending in the X and Y directions. Ferrule 420 has a window portion 425 a that opens in upper surface 425 . The window portion 425 a is a through hole formed from the upper surface 425 toward the housing portion 430 . The window portion 425 a communicates the external space of the optical connector 400 and the housing portion 430 . Since the optical connector 400 does not have a pressing portion, no pressing portion is arranged in the window portion 425a. In this embodiment, the window portion 425 a has a size that can function as a hole for injecting the adhesive 50 into the accommodating portion 430 . The lower surface 426 is a surface extending in the X direction and the Y direction. The lower surface 426 faces the upper surface 425 in the Z direction.

The accommodation portion 430 is a space capable of accommodating the end portions of the plurality of lensed fibers 10 . The housing portion 430 is defined by an upper inner surface 431, a lower inner surface 432, a stepped surface 433, and a fiber support surface 434, as shown in FIG. The upper inner surface 431 is a surface extending along the X and Y directions. The rear end of the upper inner surface 431 in the direction X is connected to the rear end surface 422, and the front end of the upper inner surface 431 is connected to the surface defining the window 425a.

The lower inner surface 432 is a surface extending along the X direction and the Y direction, and faces the upper inner surface 431 in the Z direction. A rear end of the lower inner surface 432 in the direction X is connected to the rear end surface 422 , and a front end of the lower inner surface 432 is connected to the stepped surface 433 . The step surface 433 is a surface extending along the Y direction and the Z direction. The lower end of the stepped surface 433 in direction Z is connected to the lower inner surface 432 and the upper end of the stepped surface 433 is connected to the fiber support surface 434 . The fiber support surface 434 is a surface extending in the X and Y directions. The rear end of the fiber support surface 434 in the direction X is connected with the step surface 433 , and the front end of the fiber support surface 434 is connected with a plurality of receiving holes 435 . Fiber support surface 434 may be formed with a plurality of fiber grooves in which a plurality of lensed fibers 10 are respectively disposed.

The plurality of accommodation holes 435 are through holes in which the end portions of the plurality of lensed fibers 10 are respectively accommodated. Each accommodation hole 435 extends along the X direction. The number of accommodation holes 435 may be the same as the number of lensed fibers 10 . The rear end of each accommodation hole 435 is connected to the opening 422 a through the accommodation portion 430 , and the front end is opened at the tip surface 421 . The end portions of the plurality of lensed fibers 10 inserted into the housing portion 430 through the openings 422a pass through the housing portion 430 and are housed in the plurality of housing holes 435, respectively. Each accommodation hole 435 has a side surface 435a, as shown in FIG. The side surface 435a is a surface that circumferentially surrounds each lensed fiber 10 accommodated inside each accommodation hole 435, and extends in the X direction. In this embodiment, the position of the tip of each lensed fiber 10 in the X direction matches the position of the tip surface 421 in the X direction. Each lensed fiber 10 is entirely positioned inside each accommodation hole 435 . Each lensed fiber 10 may be positioned so that its tip portion protrudes from each receiving hole 435 into the external space of the optical connector 400 .

An adhesive 50 for fixing the plurality of lensed fibers 10 to the ferrule 420 is placed in the window portion 425a and the accommodating portion 430, as shown in FIG. The adhesive 50 is injected into the housing portion 430 through the window portion 425a, for example. The adhesive 50 is also placed between the side surface 435a and the lensed fiber 10, as shown in FIG. The adhesive 50 is not arranged on the optical axis S. Therefore, the light emitted from the lensed fiber 10 or the light incident on the lensed fiber 10 does not pass through the adhesive 50 .

Next, a method for manufacturing the optical connector 400 will be described. First, a plurality of lensed fibers 10 are formed. The process of forming the plurality of lensed fibers 10 is the same as the content described in the first embodiment, so the description is omitted.

After the step of forming the plurality of lensed fibers 10 is completed, the plurality of lensed fibers 10 are accommodated in the ferrule 420 . Specifically, as shown in FIG. 16, the end portions of the plurality of lensed fibers 10 are housed inside the housing portion 430 through the opening 422a. At this time, the plurality of fiber main bodies 11 are accommodated in the plurality of accommodation holes 435 respectively.

Subsequently, the adhesive 50 is injected into the housing portion 430 through the window portion 425 a to fix the plurality of lensed fibers 10 to the ferrule 420 with the adhesive 50 . Thus, the manufacturing process of the optical connector 400 is completed.

As described above, in the method for manufacturing the optical connector 400 according to the second embodiment, a plurality of lensed fibers 10 are formed by the same method as the method for manufacturing the optical connector 1 according to the first embodiment. Therefore, the method for manufacturing the optical connector 400 according to the second embodiment has the same effect as the method for manufacturing the optical connector 1 according to the first embodiment.

Further, in the second embodiment, in the step of accommodating the plurality of lensed fibers 10, the plurality of lensed fibers 10 are accommodated in the plurality of accommodation holes 435, respectively. In this case, the plurality of lensed fibers 10 can be easily positioned by the plurality of accommodation holes 435 .

In the optical connector 400 according to the second embodiment, the multiple lensed fibers 10 have the same configuration as the multiple lensed fibers 10 according to the first embodiment. Therefore, the optical connector 400 according to the second embodiment has the same effect as the optical connector 1 according to the first embodiment.

In addition, in the second embodiment, the ferrule 420 has a plurality of receiving holes 435 in which end portions of the plurality of lensed fibers 10 are respectively received. In this case, the plurality of accommodation holes 435 facilitate positioning of the plurality of lensed fibers 10 and prevent positional deviation of the plurality of lensed fibers 10 .

Modifications 1 to 9 of the second embodiment will be described with reference to FIGS. 18 to 26. FIG. In the description of the optical connector according to each modified example, differences from the optical connector 400 according to the above-described second embodiment will be mainly described, and description of common points may be omitted.

FIG. 18 is a diagram showing a cross-sectional configuration of an optical connector 500 according to a first modified example of the second embodiment. FIG. 18 shows the peripheral configuration of the lens portion 12 in the XZ cross section of the optical connector 500. As shown in FIG. The optical connector 500 includes multiple lensed fibers 10 and ferrules 520 . The ferrule 520 differs from the ferrule 420 in that a convex portion 536 is formed on the side surface 535a of each accommodation hole 535 . The protrusion 536 is formed at the front end of the housing hole 535 (the end on the distal end surface 521 side). The convex portion 536 protrudes inward from the receiving hole 535 from the side surface 535a. The inner direction of the accommodation hole 535 means the direction toward the central axis of the accommodation hole 535 . The convex portion 536 is formed over the entire circumferential direction of the side surface 535a. The convex portion 536 restricts movement of the lensed fiber 10 in the X direction. For example, the lens portion 12 of the lensed fiber 10 housed in the housing hole 535 may be in contact with the convex portion 536 . The convex portion 536 may be used for positioning the lensed fiber 10 . According to this first modification, each lensed fiber 10 can be positioned by the convex portion 536, so that the work of inserting each lensed fiber 10 into each accommodation hole 535 is facilitated.

FIG. 19 is a diagram showing a cross-sectional configuration of an optical connector 600 according to a second modified example of the second embodiment. FIG. 19 shows the peripheral configuration of the lens portion 12 in the XZ cross section of the optical connector 600. As shown in FIG. The optical connector 600 includes multiple lensed fibers 10 and ferrules 620 . The ferrule 620 differs from the ferrule 420 in that a protrusion 636 and a recess 637 are formed on the side surface 635a of each accommodation hole 635 . The convex portion 636 has a configuration similar to that of the convex portion 536 described above. The concave portion 637 is adjacent to the convex portion 636 . The concave portion 637 is located farther from the distal end surface 621 than the convex portion 636 is. The recessed portion 637 is recessed outwardly of the receiving hole 635 from the side surface 635a. The outward direction of the accommodation hole 635 means the direction away from the central axis of the accommodation hole 635 . The recessed portion 637 is formed over the entire circumferential direction of the side surface 635a. The recess 637 may accommodate at least a portion of each lens portion 12 . For example, the recess 637 may accommodate a portion of the outer peripheral portion 12a. According to the second modified example, each lensed fiber 10 can be positioned by the convex portion 636, so that the work of inserting each lensed fiber 10 into each accommodation hole 635 is facilitated. Moreover, since at least part of the outer peripheral portion 12 a can be accommodated in the recess 637 , each lensed fiber 10 can be arranged straight in each accommodation hole 635 . Therefore, bending of the optical axis S of each lensed fiber 10 is suppressed.

FIG. 20 is a diagram showing a cross-sectional configuration of an optical connector 700 according to a third modified example of the second embodiment. FIG. 20 shows the configuration around the lens portion 12 in the XZ cross section of the optical connector 700 . The optical connector 700 includes multiple lensed fibers 10 and ferrules 720 . Ferrule 720 differs from ferrule 420 in that each receiving hole 735 is a non-through hole with a bottom. Each accommodation hole 735 is not open at the tip surface 721 . Each housing hole 735 has a bottom surface 735b at the end on the tip surface 721 side. The bottom surface 735b extends along the Y direction and the Z direction. The bottom surface 735b is connected to the end of the side surface 735a in the X direction. The bottom surface 735b faces the tip surface 721 in the X direction. The lens portion 12 may be in contact with the bottom surface 735b. The bottom surface 735 b intersects the optical axis S of the lensed fiber 10 . Light emitted from the lensed fiber 10 or light incident on the lensed fiber 10 passes through the bottom surface 735 b and the tip surface 721 . According to the third modification, each accommodation hole 735 is a non-through hole with a bottom and does not open at the tip surface 721 . Therefore, the lens portion 12 inside each accommodation hole 735 is protected.

FIG. 21 is a diagram showing a cross-sectional configuration of an optical connector 800 according to a fourth modified example of the second embodiment. FIG. 21 shows the peripheral configuration of the lens portion 12 in the XZ cross section of the optical connector 800. As shown in FIG. The optical connector 800 includes multiple lensed fibers 10 and ferrules 820 . The ferrule 820 differs from the ferrule 420 in that each receiving hole 835 is a non-through hole with a bottom and that the tip surface 21 has a plurality of lens portions 821a. Each accommodation hole 835 has the same configuration as each accommodation hole 735 described above. The tip surface 821 has a plurality of lens portions 821a. Although only one lens portion 821a is illustrated in FIG. 21, a plurality of lens portions 821a are actually arranged along the Y direction. Each lens portion 821 a faces the lens portion 12 of each lensed fiber 10 accommodated in each accommodation hole 835 in the X direction. Each lens portion 821 a is optically coupled to each lensed fiber 10 . Each lens portion 821a may have the same configuration as the lens portion 21a according to the first embodiment. According to the fourth modification, each accommodation hole 835 is a non-through hole with a bottom and does not open at the tip surface 821 . Therefore, the lens portion 12 inside each accommodation hole 835 is protected. Also, the beam diameter of the light emitted from each lensed fiber 10 can be adjusted by each lens portion 821a.

FIG. 22 is a diagram showing a cross-sectional configuration of an optical connector 900 according to a fifth modified example of the second embodiment. 22 shows the configuration around the lens portion 12 in the XZ cross section of the optical connector 900. As shown in FIG. The optical connector 900 includes multiple lensed fibers 10 and ferrules 920 . The ferrule 920 is different from the ferrule 420 in that each receiving hole 935 is a non-through hole with a bottom and that the tip surface 921 is inclined with respect to the YZ plane. Each accommodation hole 935 has the same configuration as each accommodation hole 735 described above. The inclination angle of the tip surface 921 may be 20° or less, or may be 8°. According to the fifth modification, each accommodation hole 935 is a non-through hole with a bottom and does not open at the tip surface 921 . Therefore, the lens portion 12 inside each accommodation hole 935 is protected. In addition, since the tip surface 921 is inclined with respect to the YZ plane, return light due to reflection at the tip surface 921 of light emitted from the lensed fiber 10 is reduced.

FIG. 23 is a diagram showing a cross-sectional configuration of an optical connector 1000 according to a sixth modification of the second embodiment. FIG. 23 shows the peripheral configuration of the lens portion 12 in the XZ cross section of the optical connector 1000. As shown in FIG. The optical connector 1000 includes multiple lensed fibers 10 and ferrules 1020 . Ferrule 1020 differs from ferrule 420 in that each receiving hole 1035 is a non-through hole with a bottom. Each receiving hole 1035 has a bottom surface 1035b. The bottom surface 1035b is inclined with respect to the YZ plane. The inclination angle of the bottom surface 1035b may be 20° or less, or may be 8°. The bottom surface 1035b is connected to the end of the side surface 1035a in the X direction. Each accommodation hole 1035 has the same configuration as each accommodation hole 735 described above, except that the bottom surface 1035b is inclined with respect to the YZ plane. Although the tip surface 1021 extends parallel to the YZ plane in this modification, it may be inclined with respect to the YZ plane, similarly to the bottom surface 1035b. At this time, the inclination angle of the tip surface 1021 may be 20° or less, or may be 8°. According to the sixth modification, each accommodation hole 1035 is a non-through hole with a bottom and does not open at the tip surface 1021 . Therefore, the lens portion 12 inside each accommodation hole 1035 is protected. In addition, since the bottom surface 1035b is inclined with respect to the YZ plane, return light due to reflection on the bottom surface 1035b of light emitted from the lensed fiber 10 is reduced.

FIG. 24 is a diagram showing a cross-sectional configuration of an optical connector 1100 according to a seventh modified example of the second embodiment. FIG. 24 shows the configuration around the lens portion 12 in the XZ cross section of the optical connector 1100 . The optical connector 1100 includes multiple lensed fibers 10 and ferrules 1120 . Ferrule 1120 differs from ferrule 420 in that each receiving hole 1135 is a non-through hole with a bottom. Each receiving hole 1135 has a side surface 1135a and a bottom surface 1135b. A recess 1137 is formed in the side surface 1135a. The recess 1137 is recessed outward from the receiving hole 1135 from the side surface 1135a. The outward direction of the accommodation hole 1135 means the direction away from the central axis of the accommodation hole 1135 . The recessed portion 1137 is formed over the entire circumferential direction of the side surface 1135a. The recess 1137 may accommodate at least a portion of each lens portion 12 . For example, recess 1137 may accommodate a portion of outer peripheral portion 12a. Each accommodation hole 1135 has the same configuration as each accommodation hole 735 described above, except that it has a concave portion 1137 . According to the seventh modification, each accommodation hole 1135 is a non-through hole with a bottom and does not open at the tip surface 1121 . Therefore, the lens portion 12 inside each accommodation hole 1135 is protected. Moreover, since at least part of the outer peripheral portion 12a can be accommodated in the recess 1137, each lensed fiber 10 can be arranged straight in each accommodation hole 1135. As shown in FIG. Therefore, bending of the optical axis S of each lensed fiber 10 is suppressed.

FIG. 25 is a diagram showing a cross-sectional configuration of an optical connector 1200 according to an eighth modification of the second embodiment. FIG. 25 shows the configuration around the lens portion 12 in the XZ cross section of the optical connector 1200 . The optical connector 1200 includes multiple lensed fibers 10 and ferrules 1220 . Ferrule 1220 differs from ferrule 420 in that it has plate 70 . The plate 70 has a plate shape and is attached to the tip surface 1221 . Plate 70 may be secured to tip surface 1221 using, for example, an adhesive. The plate 70 may have the same shape as the distal end surface 1221 when viewed from the direction X. Plate 70 has major surfaces 71 and 72 . Each principal surface 71, 72 is a surface extending along the Y direction and the Z direction. Principal surfaces 71 and 72 face each other in the X direction. The main surface 72 may be in direct contact with the tip surface 1221, or may be in indirect contact with the tip surface 1221 via another element such as an adhesive. The plate 70 is made of a light transmissive material. Light emitted from each lensed fiber 10 accommodated in each accommodation hole 1235 or light incident on each lensed fiber 10 passes through each principal surface 71 , 72 . According to this eighth modification, the opening of each accommodation hole 1235 in the distal end surface 1221 is blocked by the plate 70 . Therefore, the lens portion 12 inside each accommodation hole 1235 is protected.

FIG. 26 is a diagram showing a cross-sectional configuration of an optical connector 1300 according to a ninth modification of the second embodiment. FIG. 26 shows the peripheral configuration of the lens portion 12 in the XZ cross section of the optical connector 1300. As shown in FIG. The optical connector 1300 includes multiple lensed fibers 10 and ferrules 1320 . Ferrule 1320 differs from ferrule 420 in that it has plate 80 . The plate 80 has a plate shape and is attached to the tip surface 1321 . Plate 80 may be secured to tip surface 1321 using, for example, an adhesive. The plate 80 may have the same shape as the distal end surface 1321 when viewed from the direction X. Plate 80 has major surfaces 81 and 82 . Each principal surface 81, 82 is a surface extending along the Y direction and the Z direction. Principal surfaces 81 and 82 face each other in the X direction. The main surface 81 has a plurality of lens portions 81a. Although only one lens portion 81a is illustrated in FIG. 26, a plurality of lens portions 81a are actually arranged along the Y direction. Each lens portion 81 a faces the lens portion 12 of each lensed fiber 10 accommodated in each accommodation hole 1335 in the X direction. Each lens portion 81 a is optically coupled to each lensed fiber 10 . Each lens portion 81a may have the same configuration as the lens portion 21a according to the first embodiment. According to the ninth modification, the opening of each accommodation hole 1335 in the distal end surface 1321 is blocked by the plate 80 . Therefore, the lens portion 12 inside each accommodation hole 1335 is protected. Also, the beam diameter of the light emitted from each lensed fiber 10 can be adjusted by each lens portion 81a.

As described above, the method for manufacturing the optical connector 1 and the optical connector 1 according to the present disclosure are not limited to the above-described embodiments and modifications, and various other modifications are possible.

In the above-described embodiment and modified example, the curved surface portion 16 that intersects with the core 13 is a smooth curved surface that is convex toward the outside of the lens portion 12 as a whole. However, in practice, the curved portion 16 may include planar areas. A cross-sectional shape along the direction X of the planar region is a straight line. Therefore, the radius of curvature of the planar region in the cross section along the direction X becomes infinite. Moreover, the curved surface portion 16 is not limited to a flat area, and may include a recessed area recessed inside the lens portion 12 . As described above, depending on the shape of the curved surface portion 16, it may not be possible to appropriately measure or calculate the radius of curvature of the cross-sectional shape. Further, when the core 13 in the lens portion 12 has an irregular shape, the outer edge of the curved surface portion 16 may not be clearly identified on the surface 15 . Therefore, regardless of whether the curvature radius of the cross-sectional shape of the curved surface portion 16 can be appropriately measured or calculated, and whether the outer edge of the curved surface portion 16 can be clearly specified, the curved surface portion 16 in the cross section along the direction X , and the radius of curvature of the approximated curve obtained by curve approximation may be regarded as the radius of curvature of the curved surface portion 16. Alternatively, when the lensed fiber 10 is viewed from the direction X, the optical axis S is the center A region of the surface 15 included in a circle with a radius of 30 μm may be regarded as the curved surface portion 16 .

1, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300... Optical connector 2... Optical fibers 10, 110... Lensed fiber 11a... Side surface 12, 112... Lens portion 12a, 112a... Peripheral part 13... Core 14... Clad 15... Surface 16... Curved surface part 18... Fine particles 20, 120, 220, 320, 420, 520, 620, 720, 820, 920, 1020, 1120, 1220, 1320... Ferrules 21, 121, 221, 321, 421, 521, 621, 721, 821, 921, 1021, 1221, 1321... Leading end faces 21a, 81a, 821a... Lens portion 21b... Guide holes 22, 422... Rear end faces 22a, 422a Openings 23, 24 Side surfaces 25, 425 Upper surfaces 25a, 425a Window portions 26, 426 Lower surfaces 30, 430 Accommodating portions 31, 431 Upper inner surfaces 32, 432 Lower inner surfaces 33, 433 Step surfaces 34, 134, 334, 434 Fiber support surfaces 35, 135, 335 Fiber groove 35a Inner wall 36 Lens groove 36a Bottom surface 37, 137, 237, 337 Abutting surface 40 Holding portion 41 Upper surface 42 Lower surface 50 Adhesives 70, 80 Plates 71, 72, 81, 82 Main surfaces 435, 535, 635, 735, 835, 935, 1035, 1135, 1235, 1335 Accommodating holes 435a, 535a, 635a, 1135a Sides 536, 636... Convex parts 637, 1137... Concave parts 735b, 1035b, 1135b... Bottom surface

Claims (12)

a step of melting a portion of each of the plurality of optical fibers by irradiating with a laser beam to form a plurality of lensed fibers having a lens portion provided at each end;
a step of housing the plurality of lensed fibers, each having the lens portion formed therein, in a ferrule;
securing the plurality of lensed fibers to the ferrule;
with
The surface of the lens portion has a curved portion that is convex toward the outside of the lens portion and overlaps with the core of the lensed fiber,
A method for manufacturing an optical connector. The step of forming the plurality of lensed fibers includes the step of cutting each of the plurality of optical fibers by irradiating the laser light.
A method for manufacturing an optical connector according to claim 1 . In the step of forming the plurality of lensed fibers, the plurality of optical fibers are arranged side by side in an arrangement direction that intersects the extending direction of the optical fibers, and the irradiation position of the laser light is moved along the arrangement direction. By collectively forming the lens portion on each of the plurality of optical fibers,
3. The method for manufacturing an optical connector according to claim 1 or 2. a plurality of lensed fibers;
a ferrule capable of holding the plurality of lensed fibers,
each lensed fiber has a fiber body extending in a first direction inside the ferrule and a lens portion integrally provided at an end of the fiber body;
The surface of the lens portion has a curved portion that is convex toward the outside of the lens portion and intersects with the core of the lensed fiber,
optical connector. The lens portion has a rotationally asymmetric shape with respect to the optical axis of the lensed fiber,
The optical connector according to claim 4. The lens part has a shape that is rotationally symmetrical with respect to the optical axis of the lensed fiber,
The optical connector according to claim 4. The lens portion has an outer peripheral portion that protrudes from the side surface of the fiber body in a direction away from the optical axis of the lensed fiber,
The optical connector according to any one of claims 4 to 6. A curvature radius of the curved surface portion in a cross section along the first direction is 10 mm or more and 500 mm or less.
The optical connector according to any one of claims 4 to 7. The ferrule is
tip surface;
an opening provided on the side opposite to the tip surface in the first direction;
a plurality of fiber grooves extending along the first direction between the distal end face and the opening, each of which can accommodate a plurality of the fiber bodies;
a lens groove that is located closer to the distal end surface than the plurality of fiber grooves and that can accommodate at least a portion of the lens portion;
The optical connector according to any one of claims 4 to 8. The ferrule has an abutment surface located inside the ferrule and facing the lens portion and intersecting with the optical axis of the lensed fiber, and an abutment surface located outside the ferrule and facing the abutment surface, including the tip surface intersecting the optical axis of the lensed fiber;
At least one of the abutment surface and the tip surface is inclined with respect to a plane perpendicular to the optical axis of the lensed fiber,
The optical connector according to claim 9. the ferrule has a window facing at least part of the region in which the plurality of fiber grooves are formed;
The optical connector further comprises a pressing portion arranged in the window portion and pressing the plurality of lensed fibers toward the plurality of fiber grooves.
The optical connector according to claim 9 or 10. further comprising an adhesive that secures the plurality of lensed fibers to the ferrule;
The adhesive is provided at a position that intersects the optical axis of each of the plurality of lensed fibers,
the refractive index of the adhesive is smaller than the refractive index of each core of the plurality of lensed fibers;
The optical connector according to any one of claims 4 to 11.

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