JP2005309367A - Optical fiber connector, optical fiber connecting body and connecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optically connect optical fibers, be machinable on site, and reducible in size at low cost. <P>SOLUTION: An optical fiber connector is used to optically connect a pair of optical fibers with their tips opposing each other. The optical fiber connector is formed of a material having a higher thermal deformation temperature than that of the coverings 12 of the optical fibers 10. The connector has a positioning guide hole 22 for inserting therein the optical fibers 10 and also has fiber-fixing groove portions 23 circumferentially formed in the wall of the guide hole 22. When the coverings 12 of the optical fibers 10 are thermally deformed, parts of the coverings 12 bite the groove portions 23, whereby the optical fibers 10 are fixed in the guide hole 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical fiber connector for optically connecting optical fibers in optical communication technology, optical transmission technology, and the like, and an optical fiber connector in which optical fibers are optically connected using the optical fiber connector. About. The present invention also relates to an optical fiber connection method for optically connecting optical fibers using an optical fiber connector.

  In recent years, optical communication technology and optical transmission technology have come to be used not only for trunk systems but also for access systems, as represented by FTTH. Furthermore, in Gigabit Ethernet (registered trademark), 10G Ethernet (registered trademark), and the like, it is becoming widely used to connect high-speed and large-capacity optical transmission by connecting devices with optical fibers. At the current research and development level, an attempt is made to apply optical wiring between a plurality of LSIs mounted on a board. In that case, many optical transmission paths are premised on the realization of an opto-electric mounting board in which an optical waveguide is embedded in an electric mounting board, but the opto-electric mounting board is realized by stabilizing the optical coupling system, etc. It still has issues that require breakthrough, and it is difficult to immediately put it to a practical level.

  Thus, optical fibers, waveguide films, and the like are examples of optical transmission lines that are used transiently or simply. However, at the present stage, the transmission loss of the waveguide film is 3 to 4 digits larger than that of the optical fiber, and it is effective to use the optical fiber when connecting a relatively long distance.

  The optical fiber includes a silica-based fiber used in optical communication and the like, and a POF (plastic optical fiber) used in an automobile control system. In the case of an application for transmitting an LSI signal, it is necessary to increase the signal transmission band per channel as much as possible, and it is necessary to transmit a signal with a high frequency such as 10 GHz. In this case, in the POF having a large core diameter, the product of the bandwidth and the length is limited due to the dispersion. Although small-diameter POFs are also commercially available, they are not common because they are still used in small quantities and are expensive. Therefore, it is preferable to use a glass fiber.

  Further, when considering an application in which LSIs are connected to each other with an optical fiber on a board, it is necessary to adjust the length connecting the LSIs. In such a case, a method of providing an optical connector on the end face of the optical fiber connected to the LSI is conceivable. However, this method is not practical because the end face processing (particularly the polishing step) of the optical fiber is very costly. .

For this reason, a method of performing semi-permanent connection by performing end faceting by stress rupture without polishing becomes effective. Generally called mechanical splice. For example, there is a method of fixing by inserting a fiber into a thin tube called a sheath and crushing the sheath (see, for example, Patent Document 1). Also, a counterbore for holding the optical fiber is provided on the aluminum split sleeve, the optical fiber whose end face is exposed by stress rupture is abutted, and the split sleeve is applied with compressive force applied from both sides in the axial direction of both fibers. There is a structure to fix by caulking. According to this structure, an optical fiber can be connected on-site using a tool without requiring a polishing step, and the member cost can be realized at a low cost (see, for example, Patent Document 2).
JP-A-4-124606 JP-A-2-12112

  However, in the case of Patent Document 1, since the connection end face is polished, the process cost is high, the cost is high, and it is necessary to deform each sheath using a sheath as a separate part, so that the tool becomes large. There were issues such as difficulty in connecting on-site. Further, since the optical fiber is fixed only by fitting with the sheath, there is a problem that the optical fiber holding portion is easily displaced due to thermal expansion or the like.

  On the other hand, in the case of Patent Document 2, processing can be performed on-site, but since the optical fiber strands are held together by an aluminum split sleeve, positional displacement does not occur due to deformation of the sleeve when caulking. Since it is necessary to have a structure and a certain material strength is required to maintain the shape of the fiber holding hole of the sleeve, it is difficult to fabricate the resin. In addition, even when made of metal, there is a problem that the structure tends to increase in size.

  The present invention has been made in consideration of the above circumstances, and an object thereof is to provide an optical fiber connector, an optical fiber connector, and an optical fiber that can be processed on-site and can be reduced in size at low cost. It is to provide a connection method.

  In order to solve the above problems, the present invention adopts the following configuration.

  That is, according to one aspect of the present invention, at least one pair of optical fibers has guide holes that are positioned and face each other, and a fiber fixing groove is provided along the circumferential direction on the inner surface of the guide hole. An optical fiber connector, wherein the optical fiber connector is formed using a resin material having a higher thermal deformation temperature than a covering member of the optical fiber.

  Another aspect of the present invention is an optical fiber connector for optically connecting opposing optical fibers by positioning and opposing the ends of at least one pair of optical fibers. It is made of a material having a heat deformation temperature higher than that of the coating portion of the optical fiber, provided with a positioning guide hole into which the optical fiber is inserted, and provided with a fiber fixing groove portion along the circumferential direction on the inner surface of the guide hole. The optical fiber is fixed to the guide hole by causing a part of the coating portion to bite into the groove portion by thermal deformation of the coating portion of the optical fiber.

  According to another aspect of the present invention, at least one pair of optical fibers and the ends of the pair of optical fibers are positioned and opposed to each other so that the facing optical fibers are optically connected to each other. And a transparent adhesive filled in a facing portion of the optical fiber, wherein the connector has a thermal deformation temperature higher than that of the coating portion of the optical fiber. A positioning guide hole that is formed of a high material, is provided through the connector, and into which the optical fiber is inserted, and a fiber fixing groove formed in the inner surface of the guide hole along the circumferential direction, An adhesive injection hole for filling the transparent adhesive in an opposite portion of the optical fiber, the transparent adhesive being a refractive index matching agent for the optical fiber, and covering the optical fiber The thermal deformation, characterized by comprising fixing the optical fiber in the guide hole by bite into a portion of the covering portion in the groove.

  Another aspect of the present invention is an optical fiber connection method using the optical fiber connector configured as described above, wherein at least the covering portion in the vicinity of the end surface to be optically connected is removed and the optical end surface is projected. Inserting a pair of optical fibers into the guide hole of the optical fiber connector from both sides to make the end faces of the fibers face each other, and applying heat treatment to the coated portion of the optical fiber during or after insertion of the optical fiber And fixing the optical fiber in the guide hole by causing the coating portion to be thermally deformed and causing a portion of the coating portion to bite into the groove portion.

  Another aspect of the present invention is an optical fiber connection method, in which at least a pair of optical fibers whose end portions are removed and whose optical end faces are inserted are inserted into the ferrule positioning guide holes from both sides. And applying a pressing force in the axial direction of the optical fiber to each of the end faces of the optical fiber facing each other, a step of heating the ferrule, and a caulking member to the ferrule in the axial direction of the optical fiber. Connecting the end faces of the at least one pair of optical fibers by applying a pressing force in a parallel direction and a vertical direction.

  Another aspect of the present invention is an optical fiber connector, which includes a ferrule for holding a plurality of optical fibers, and a direction perpendicular to and parallel to an axial direction of the optical fiber. And a crimping member for applying pressure.

  According to the present invention, the optical fiber connector is provided with a positioning guide hole having a fiber fixing groove portion, and a part of the covering portion is bitten into the groove portion by thermal deformation of the covering portion of the optical fiber. Since the structure is fixed, only the axial force of the optical fiber is applied to the butted portion of the optical fiber, that is, the optical coupling portion, and a structure in which no lateral force is applied can be obtained. Therefore, the guide hole need not be made of a robust material in order to prevent initial misalignment of the optical fiber, and can be realized by a member such as a resin, and the range of material selection can be expanded. There is an effect. Therefore, it is possible to provide a small-sized connector at low cost. In addition, since it is only necessary to warm the coating portion to a temperature at which it can be thermally deformed, on-site processing can be performed relatively easily, and no other parts are required. Is possible.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Accordingly, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Further, the following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, and arrangement of components. Etc. are not specified below. The technical idea of the present invention can be variously modified within the scope of the claims.

(First embodiment)
FIG. 1 is a sectional view showing a schematic configuration of an optical fiber connector according to the first embodiment of the present invention.

  In the figure, 10 (10-1, 10-2) is an optical fiber, and this optical fiber 10 is obtained by covering a core 11 as a transmission path with a covering portion 12. The core 11 may be quartz or plastic. The covering portion 12 is a primary covering for increasing durability against external forces such as bending and rubbing, and the material thereof may be formed of a single layer or a plurality of layers such as UV effect resin, soft plastic, and polyamide resin. .

  After a part of the covering portion 12 at the end of the optical fiber 10 is removed (13 in the figure is the end portion of the optical fiber 10 and the covering portion 12 is removed), the stress rupture is used. In a state where the optical end faces are made, they are inserted from both sides into a guide hole of a ferrule to be described later so that the end faces face each other.

  In the figure, reference numeral 20 denotes an optical fiber connector of the present embodiment. This optical fiber connector 20 is provided with a positioning guide hole 22 in a ferrule (connector body) 21 formed in a cylindrical shape, and further a guide hole 22. Is provided with a fiber fixing groove 23.

  Ferrule 21 is made of a metal such as aluminum or a ceramic material such as zirconia, or glass, epoxy resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, phenol resin, polyester resin, polyimide resin, or fluorine resin. Liquid crystal polymers can be used. Of these various materials, the heat-resistant temperature (here, the lowest temperature at which the bending elastic modulus of the material is not more than half the room temperature) may be higher than the temperature at which the covering portion 12 of the optical fiber 10 is thermally deformed. In particular, it is preferable to use an epoxy resin mixed with about 70 to 80% of a glass filler of about 5 to 30 μm because the guide hole 22 can be easily formed by resin molding using a mold.

  The guide hole 22 is provided so as to penetrate the central portion of the ferrule 21 along the axial direction of the ferrule 21, and the inner diameter thereof is larger by about 1 to 2 μm than the outer diameter of the optical fiber 10. The groove portion 23 is provided in the vicinity of both ends of the guide hole 22. Each groove portion 23 is formed by forming a plurality of V-shaped grooves on the inner surface of the guide hole 22 along the circumferential direction.

  FIG. 2 is a process cross-sectional view for explaining the optical fiber connecting method according to the present embodiment.

  In FIG. 2A, the end portion 13 of the optical fiber 10 has the covering portion 12 removed to form an optical input / output end face 14. This end face 14 is formed by stress rupture or the like, and is an optical end face. The guide hole 22 of the ferrule 21 is slightly larger than the optical fiber 10 (for example, 1 μm in diameter), and a groove portion 23 is formed in a part thereof. The groove 23 is formed so as not to protrude from the guide hole 22.

  In this state, the end faced optical fiber 10 is inserted into the guide hole 22 as shown in FIG. At this time, a part of the covering portion 12 of the inserted optical fiber 10 is caught in the groove portion 23. In this state, the same optical fiber 10 is inserted from the opposite direction, and the end face 14 is brought into contact with each other, and is kept pressed from the outside.

  When heat treatment is performed in this state, as shown in FIG. 2C, the covering portion 12 flows due to thermal deformation and fills the gaps in the groove portion 23 to some extent. Due to this deformation, the optical fibers 10 on both sides are fixed, and optical coupling is realized in a state of end face butt.

  Further, when the inner diameter of the groove portion 23 is set larger than the covering portion 12 of the optical fiber 10, there is no such catch when the optical fiber 10 is inserted, and the insertion can be performed smoothly. In this case, however, the covering portion 12 is naturally not caught as shown in FIG. Next, when the covering portion 12 is heated with the optical fiber 10 on the opposite side inserted and abutted against it, and the optical fiber 10 is pressed in the direction of mating, the covering portion 12 is pushed into the connector. Since the applied force works, the groove portion 23 is filled with a part of the deformed covering portion 12 to ensure the state of FIG. In this case, since the insertion can be performed smoothly, there is an effect that the end face of the fiber can be reliably secured.

  The inner diameter of the groove 23 is the innermost diameter of the annular groove 23 provided in the guide hole 22. In the present embodiment, the inner diameter is the same as the diameter of the guide hole 22. If the smoothness at the time of insertion of the optical fiber 10 is sacrificed, the inner diameter of the groove 23 can be made smaller than the diameter of the guide hole 22 and the optical fiber can be caught more reliably.

  FIG. 3 shows a modification of the groove shape. In this example, the cross-sectional shape of the groove 23 is serrated, and in each groove, the ferrule center side is a gently inclined surface with respect to the optical axis, and the opposite side (outward direction) has an acute normal to the optical axis. It has a steep slope. According to this structure, when the optical fiber is inserted, the resistance due to the groove 23 is reduced, and after the thermal deformation, the effect of returning is obtained, and the strength is increased in the direction in which the optical fiber 10 is pulled out.

  As described above, according to this embodiment, the positioning guide hole 22 is provided in the ferrule 21 and the fiber fixing groove portion 23 is provided in the guide hole 22 so that the optical fiber 10 is inserted from both sides of the guide hole 22 and heated. By performing the treatment, the covering portion 12 of the optical fiber 10 is thermally deformed and bites into the groove portion 23, whereby the optical fiber 10 can be held and fixed. That is, the optical connection of the pair of optical fibers 10 can be realized by the optical fiber connector 20 having a small and simple configuration, and its usefulness is great.

(Second Embodiment)
FIG. 4 is a cross-sectional view showing a schematic configuration of an optical fiber connector according to the second embodiment of the present invention.

  In FIG. 4, 21 is a ferrule (connector body), which has a structure in which a plurality of cylindrical shapes are connected in the axial direction. The ferrule 21 is made of epoxy resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, phenol resin, polyester resin, polyimide resin, fluorine resin, or the like. In particular, it is preferable to use an epoxy resin in which about 30% of a glass filler of about 30 μm is mixed because the ferrule 21 can be easily formed by resin molding using a mold. The ferrule 21 is formed by narrowing the outer shape at both ends to form a holding portion 26, and an uneven portion (groove portion) 23 is formed in the guide hole 22 of the holding portion 26. When the optical fiber 10 is held by the ferrule 21, the concavo-convex portion 23 functions to prevent the coating portion 12 of the optical fiber 10 from biting and shifting in the X-axis direction in FIG. Further, the guide hole 22 is thin at the center portion of the ferrule 21, and this portion is an optical fiber guide 25.

  In the ferrule 21, the holding portion 26 is displaced inward by the cylindrical caulking member 29-1 being pushed in the positive direction of the X axis and the caulking member 29-2 being pushed in the negative direction of the X axis. With this structure, the optical fiber 10 inserted into the ferrule 21 is firmly fixed.

  At this time, in the vicinity of the end face where the pair of optical fibers contact, the ferrule 21 is not deformed because the deformable force does not reach, so even if a deformable material such as a resin is used, it is almost the original. The upper limit of connection loss can be defined as designed.

  FIG. 5 is a perspective view showing a state in which the optical fiber connector of the present embodiment actually connects the optical fibers, and FIG. 6 is a cross-sectional view taken along line A-A ′. FIG. 5 shows a perspective view of an example of a connector for one fiber. This figure shows a state immediately before the covering portion 12 of the optical fiber 10 is caulked by the caulking members 29 (29-1, 29-2). In the figure, reference numeral 27 denotes a slit which is inserted in the holding portion 26 of the ferrule 21 in the axial direction, and the holding portion 26 has a split sleeve-like structure. By pressing the caulking member 29 inward from both sides (see the arrow in the figure), the inner diameter of the holding portion 26 is reduced, and the concave and convex portion 23 bites into the covering portion 12.

  In FIG. 5, reference numeral 10 denotes an optical fiber, which may be a silica-based fiber used in optical communication or the like, or a plastic-based fiber (POF) used in an in-vehicle control system. The optical fiber 10 is obtained by coating a core 11 with a covering portion 12. The covering portion 12 needs to have durability against external forces such as bending and rubbing, and the material is UV curable resin, soft plastic, polyamide resin, or the like. The covering portion 12 has a single layer structure made of one of these resins or a plurality of layers of these resins.

  Each of the optical fibers 10 does not have a coating on its end portion 13 and is formed by performing optical end faceting using stress fracture. The pair of optical fibers 10 are inserted into the guide holes 22 of the ferrule 21 from the directions on both sides of the positive and negative sides of the X axis, and the cores 11 exposed from the ends are inserted into the optical fiber guide 25 from the directions of both positive and negative sides of the X axis Thus, the end surfaces 14 are opposed to each other. The inner diameter of the guide hole 22 is about 1 to 2 μm larger than the outer diameter of the optical fiber 10, and the inner diameter of the optical fiber guide 25 is slightly larger than the core diameter of the optical fiber 10.

  As described above, the optical fiber 10 pushes the caulking member 29-1 in the positive direction of the X axis and the caulking member 29-2 in the negative direction of the X axis, so that the holding portion 26 of the ferrule 21 is moved inward. It is held by being displaced. Therefore, as shown in FIG. 5, the caulking member 29 has a tapered inner diameter portion, and the holding portion 26 of the ferrule 21 is provided with a slit 27. Resin, metal, or the like can be used as the material of the caulking member 29, but resin is preferable in order to reduce costs. Therefore, the same ferrule 21 can be used. Furthermore, the fixing strength of the optical fiber 10 is improved because the convex and concave portions 23 bite into the covering portion 12.

  As described above, in the optical fiber connector according to the present embodiment, even if a slight gap is generated between the end faces of the pair of optical fibers 10, there is no problem. In this case, the loss and reflection of the optical signal tend to increase slightly, but the system may be designed in consideration of this.

  Since the mechanism for holding the optical fiber 10 can be realized by a mechanical deformation mechanism such as the caulking member 29 by adopting the structure as in the present embodiment, the apparatus itself is made an inexpensive structure using resin or the like. Can do.

  Using the optical fiber connector as described above, the pair of optical fibers are connected as follows. 7A to 7C are process cross-sectional views illustrating the optical fiber connecting method according to the present embodiment.

  First, in the optical fiber 10, after the coating portion 12 is partially removed, the region of the optical fiber 10 exposed by removing the coating portion 12 is disconnected by means such as stress rupture so that the optical end face is exposed. deep. Thereby, the end surfaces 14-1 and 14-2 are formed.

  Then, as shown in FIG. 7A, the end of the pair of optical fibers 10 where the end face of one optical fiber 10-1 is exposed is inserted from one opening of the guide hole 22 of the ferrule 21, and the end face is exposed. The core 11 thus formed is inserted from one opening of the optical fiber guide 25. Further, the optical fiber 10 is held by the external holding mechanism 31 in a state where the optical fiber 10 is bent. The other optical fiber 10-2 is also inserted from the other opening of the guide hole 22 of the ferrule 21 in the same manner, the respective end faces of the optical fibers 10-1 and 10-2 are brought into contact with each other, and the optical fiber 10 is kept pressed. -1 and 10-2 are held in a state of being bent.

  Next, as shown in FIG. 7B, the vicinity of the holding portion 26 of the ferrule 21 is heated by the heater 33. Then, as shown in FIG. 7 (c), by pressing the caulking members 29-1 and 29-2 that have passed through the optical fibers 10-1 and 10-2 in advance from both the positive and negative sides of the X axis, slits are obtained. As the width of 27 is reduced and the inner diameter of the holding portion 26 is reduced, the concavo-convex portion 23 bites into the covering portion 12 (see the arrow in FIG. 7C). At this time, if the temperature of the holding part 26 is made higher than the softening temperature of the covering part 12 by the heating step of FIG. 7B, the uneven part 23 can be more effectively bited into the covering part 12. By keeping the portions other than the hold portion 26 such as the optical fiber guide 25 from being heated, deformation of the optical fiber guide 25 can be suppressed. Thereafter, the heater 33 is removed, and the temperature of the entire apparatus is lowered to room temperature, whereby the covering portion 12 is cured and functions as an adhesive to fix the optical fibers 10-1 and 10-2.

  During the series of steps, the optical fiber guide 25 is prevented from applying unnecessary force and heat as much as possible. By doing so, it is possible to connect the optical fibers with a simple structure while maintaining the optical coupling between the optical fibers 10-1 and 10-2.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. The difference between the present embodiment and the second embodiment is that the optical fiber guide 25 has a curved shape instead of a straight tubular shape.

  With such a structure, when the optical fibers 10-1 and 10-2 come into contact with the end face 14, a residual stress is generated in the X-axis direction due to the buckling force of the optical fiber itself. And photocoupling is maintained. Furthermore, since the optical fibers 10-1 and 10-2 are guided along one wall surface of the optical fiber guide 25, the radial deviation of the outer periphery of the covering portion of both optical fibers to be abutted is minimized. It is possible. For this reason, even when the accuracy of the diameter of the optical fiber guide 25 is larger than the accuracy and eccentricity of the optical fiber outer periphery, the butt is held with the optical fiber outer periphery accuracy and the eccentricity accuracy.

(Fourth embodiment)
Next, an optical fiber connector which is a fourth embodiment of the present invention will be described with reference to FIG.

  The present embodiment is different from the first embodiment described above in that an adhesive injection hole 24 for injecting a transparent adhesive as a refractive index matching agent is provided in the ferrule 21. Similarly to the second embodiment, the ferrule 21 is formed with an optical fiber guide 25 and a holding portion 26, and is provided with an adhesive injection hole 24 penetrating from the central portion of the optical fiber guide 25 to the upper surface. . Further, as in the second embodiment, the hole diameter in the optical fiber guide 25 is smaller than the guide hole 22 in the holding portion 26.

  In the optical fiber connection methods of the first and second embodiments, there is a temperature cycle in which the temperature is lowered to room temperature after heating the ferrule 21, so that the optical fiber guide 25 itself is deformed due to the deformation of the ferrule 21. there's a possibility that. This results in positional displacement of the end faces 14 of the optical fibers 10-1 and 10-2 and joining / detaching of the end faces 14. Therefore, if the refractive index matching agent as the transparent adhesive 41 is injected from the adhesive injection hole 24 as shown in FIG. 9, the position shift, the sudden change in the refractive index due to the debonding, and the end face reflection associated therewith. Can be prevented.

  Further, the vicinity of the connection point of the optical fiber 10 is fixed by a transparent adhesive 41. When resin is used for the adhesive 41 and the ferrule 21, the position of the end face of the optical fiber 10 can be displaced in the plane to the extent of the difference between the ferrule inner diameter and the fiber outer diameter. There may be a slight gap between the end faces. Thus, it goes without saying that the system needs to be designed in consideration of the tendency that the loss and reflection of optical signals increase. At this time, since the transparent adhesive 41 also serves as the refractive index matching agent for the optical fiber 10, light reflection can be dramatically reduced.

  By adopting such a structure, the mechanism for holding the optical fiber 10 can be placed away from the end face 14 of the optical fiber 10, that is, the holding portion of the optical fiber 10 and the optical coupling portion are separated. It has a structure. For this reason, it is possible to realize the holding mechanism with a mechanical deformation mechanism such as contact fitting in a state in which the optical coupling portion (= fiber end surface portion) is not displaced. It can be a structure. Further, after the optical connection is fixed by fitting, the transparent adhesive 41 is completely solidified in the vicinity of the connection portion, whereby the mechanical strength can be ensured. The connection strength of 10 can be maintained.

  FIG. 10 is a process cross-sectional view illustrating the optical fiber connecting method according to the present embodiment.

  The optical fiber 10 is in a state in which the optical end face is exposed by means such as stress fracture after removing a part of the covering portion 12 so that the vicinity of the end face is exposed. The side where the end face is exposed is inserted into the guide hole 22 of the ferrule 21 and held by the external holding mechanism 31 with the covering in a state of being bent. The other optical fiber 10 is also inserted from the other opening of the guide hole 22 of the ferrule 21 in the same manner, and the end face is brought into contact with the optical fiber 10 and held in a state of being bent while maintaining the pressure (FIG. 10 ( a)).

  Next, the vicinity of the holding portion 26 of the ferrule 21 is heated by the heater 33, and the covering portion 12 of the optical fiber 10 is deformed to be fitted into the groove portion 23. Thereby, the optical fiber 10 is fixed to the ferrule 21 (see FIG. 10B).

  Next, after the external holding mechanism 31 is removed, the transparent adhesive 41 is injected from the injection hole 24 and is distributed near the connection portion of the optical fiber 10 (see FIG. 10C). Thereafter, the transparent adhesive 41 is cured and completely fixed (see FIG. 10D).

  In this series of operations, it is possible to connect the optical fiber while maintaining the optical coupling by preventing unnecessary force and heat from being applied to the optical fiber guide 25 as much as possible.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIG. In this embodiment, a caulking member 29 (29-1, 29-2) is added to the fourth embodiment.

  In the present embodiment, a caulking member 29 is prepared as a separate part outside to assist deformation fitting of the covering portion 12, and the caulking member 29 is left after completion. As shown in FIG. 11, the caulking member 29 has a tapered inner diameter portion, and has a structure in which the holding portion 26 is caulked by sliding inward in the axial direction of the optical fiber 10. . Resin, metal, etc. can be used as the material, but a resin is preferable in order to reduce the member cost, and the same material as the ferrule can be used as the material system.

  The manufacturing process of this embodiment is basically the same as that shown in FIG. 10 except that a caulking member 29 is used. That is, in the step of deforming in FIG. 10B, the caulking member 29 that has been passed in advance is pressed from both sides so that the groove portion 23 bites into the covering portion 12. As a result, it is possible to maintain the caulking effect by ensuring that the deformation fitting is performed more securely and finally fixing the caulking member 29, thereby improving the reliability. is there.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described with reference to FIG. Although the example applied to the single core optical fiber was demonstrated in the 1st-5th embodiment, the example applied to the multiple optical fiber array is shown in this embodiment.

  FIG. 12A is a cross-sectional view of a surface orthogonal to the axial direction of the optical fiber, in which 51 is a core, 52 is a primary coating portion, and 53 is a secondary coating portion. Four optical fibers in which the core 51 is covered with the primary covering portion 52 are covered with the secondary covering portion 53, and the optical fiber array 50 is formed. This entire structure is called a tape core wire in which a plurality of optical fiber core wires (core + primary coating) are combined in a ribbon shape.

  FIG. 12B is a front view of the ferrule 61 of this embodiment as viewed from the axial direction of the guide hole. Reference numeral 66 denotes a holding part in which both sides of the ferrule 61 are narrowed, and a slit 67 is formed in a part of the holding part 66. Reference numeral 62 denotes a guide hole into which the optical fiber array 50 is inserted, and reference numeral 65 denotes a guide hole (optical fiber guide) into which each core 51 of the optical fiber array 50 is inserted.

  FIG.12 (c) is the perspective view which showed a mode that an optical fiber was connected by the optical fiber connector of this embodiment. Similar to the first embodiment, a fiber fixing groove 63 is formed in the vicinity of the opening of the guide hole 62. As in the first embodiment, the optical fiber array 50 is inserted into the guide hole 62 after the optical end face is projected, and each core 51 is inserted into the optical fiber guide 65 and fixed. At this time, the optical fiber array 50 can be fixedly held in the groove 63 by performing heat treatment to thermally deform the secondary coating 53 of the optical fiber array 50. Moreover, you may make it perform more reliable fixation using a crimping member. In FIG. 12C, for convenience of explanation, one optical fiber array 50 is shown, but it goes without saying that there is another optical fiber array 50 at an opposing position.

(Modification)
Each embodiment mentioned above illustrates the device and method for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, arrangement of components. Etc. are not limited to only those disclosed in the embodiments. The present invention can be variously modified and implemented without departing from the spirit of the present invention.

  For example, the shape of the ferrule or caulking member of the embodiment already described is not limited to the coaxial shape as shown in the figure, and may be another shape such as a parallel plate type. Further, the groove portion is not limited to the coaxial shape, and may have a dimple shape in which the concave portions are arranged in the circumferential direction.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

Sectional drawing which shows schematic structure of the optical fiber connector concerning 1st Embodiment. Sectional drawing for demonstrating the connection method of the optical fiber by 1st Embodiment. Sectional drawing which shows the example which changed the groove part shape as a modification of 1st Embodiment. Sectional drawing which shows schematic structure of the optical fiber connector concerning 2nd Embodiment. The perspective view which shows schematic structure of the optical fiber connector concerning 2nd Embodiment. FIG. 6 is a cross-sectional view taken along the line A-A ′ in FIG. 5. Process sectional drawing for demonstrating the connection method of the optical fiber by 2nd Embodiment. Sectional drawing which shows schematic structure of the optical fiber connector concerning 3rd Embodiment. Sectional drawing which shows schematic structure of the optical fiber connector concerning 4th Embodiment. Process sectional drawing for demonstrating the connection method of the optical fiber by 4th Embodiment. Sectional drawing which shows schematic structure of the optical fiber connector concerning 5th Embodiment. The figure which shows schematic structure of the optical fiber connector concerning 6th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Optical fiber 11, 51 ... Core 12, 52 ... Cover part 13 ... Fiber end part 14 ... Fiber end surface 20 ... Optical fiber connector 21, 61 ... Ferrule (connector main body)
22, 62 ... Positioning guide holes 23, 63 ... Fiber fixing grooves 24 ... Adhesive injection holes 25, 65 ... Optical fiber guides 26, 66 ... Holding parts 27, 67 ... Slit parts 29 ... Caulking members 31 ... External holding mechanisms 33 ... Heater 41 ... Transparent adhesive 50 ... Optical fiber array 53 ... Secondary coating part

Claims (20)

An optical fiber connector having a guide hole that positions and opposes the ends of at least one pair of optical fibers, and a fiber fixing groove is provided on the inner surface of the guide hole along the circumferential direction.
The optical fiber connector is formed using a resin material having a higher thermal deformation temperature than the coating member of the optical fiber. An optical fiber connector for optically connecting opposing optical fibers by positioning and opposing the ends of at least one pair of optical fibers,
It is made of a material having a heat deformation temperature higher than that of the coating portion of the optical fiber, provided with a positioning guide hole into which the optical fiber is inserted, and provided with a fiber fixing groove portion along the circumferential direction on the inner surface of the guide hole. An optical fiber connector, wherein the optical fiber is fixed in the guide hole by causing a part of the coating portion to bite into the groove portion by thermal deformation of the coating portion of the optical fiber.   The optical fiber connector according to claim 1 or 2, further comprising an adhesive injection hole for filling a transparent adhesive in an opposite portion of the optical fiber.   4. The optical fiber connector according to claim 3, wherein the transparent adhesive is a refractive index matching agent for the optical fiber.   The light according to any one of claims 1 to 4, further comprising a caulking member that is fitted into an end portion in a direction in which the guide hole is opened, and that presses the optical fiber from the outside at the end portion. Fiber connector.   6. The optical fiber connector according to claim 1, wherein an inner diameter of the groove is equal to or larger than an outer shape of the coating portion of the optical fiber.   The groove portion has a V-shaped cross section along the axial direction of the guide hole, the inclination of the V-shaped cross section on the center side of the optical fiber connector is gentle, and the inclination on the opposite side is steep. The optical fiber connector according to any one of claims 1 to 6,   The optical fiber connector according to claim 1, wherein the optically connected end face of the optical fiber is an end face formed by stress fracture. A connector for optically connecting the optical fibers facing each other by positioning at least one pair of optical fibers and the tips of those optical fiber pairs facing each other; An optical fiber connector comprising a transparent adhesive filled in an opposing portion,
The connector is formed of a material having a higher thermal deformation temperature than the coating portion of the optical fiber, and is provided through the connector, and a positioning guide hole into which the optical fiber is inserted, and the guide hole It has a fiber fixing groove formed on the inner surface along the circumferential direction, and an adhesive injection hole for filling the transparent adhesive in the opposite portion of the optical fiber, and the transparent adhesive is the light A refractive index matching agent for a fiber, wherein the optical fiber is fixed to the guide hole by causing a part of the coating to bite into the groove by thermal deformation of the coating of the optical fiber. Optical fiber connector. The optical fiber connector according to claim 1, wherein at least a pair of optical fibers whose optical end surfaces are removed by removing the coating portion in the vicinity of the end surface to be optically connected are inserted into the guide holes of the optical fiber connector from both sides. And making the end faces of the fibers face each other,
When the optical fiber is inserted or after insertion, the coating portion of the optical fiber is subjected to a heat treatment, and the coating portion is thermally deformed so that a part of the coating portion bites into the groove portion, whereby the optical fiber is guided to the guide hole. Fixing to
An optical fiber connection method comprising:   11. The method of connecting optical fibers according to claim 10, wherein after the step of fixing the optical fiber to the guide hole, a transparent adhesive is filled in a facing portion of the optical fiber and the adhesive is cured.   When the coating portion is deformed by the heat treatment, a caulking member is fitted into an end portion of the optical fiber connector in the direction in which the guide hole opens, and the optical fiber is pressed from the outside by the end portion of the optical fiber connector. The optical fiber connection method according to claim 10 or 11, wherein: At least a pair of optical fibers whose end portions are removed and whose optical end faces are inserted are inserted into the ferrule positioning guide holes from both sides, respectively, and the respective end surfaces of the opposed optical fibers are arranged in the axial direction of the optical fibers. Applying a pressing force;
Heating the ferrule;
Connecting the end faces of the at least one pair of optical fibers by applying a pressing force to the ferrule by a caulking member in a direction parallel to and perpendicular to the axial direction of the optical fiber;
An optical fiber connection method comprising:   14. The method of connecting optical fibers according to claim 13, wherein the step of heating the ferrule is a step of heating so that the coating holding portion of the optical fiber is at a higher temperature than other portions.   15. The optical fiber connecting method according to claim 13, further comprising a step of injecting a refractive index matching agent into the end faces of the at least one pair of optical fibers after the optical fibers are bonded.   In the step of applying a pressing force in the axial direction of the optical fiber, the pressing force is applied to the end faces of two optical fibers having a coating made of a material selected from a UV curable resin, a soft plastic, and a polyamide resin. The optical fiber connection method according to claim 13.   16. In the step of applying a pressing force in a direction perpendicular to the axial direction of the optical fiber, the pressure is applied to such an extent that the concavo-convex portion provided on the ferrule bites into the coating of the optical fiber. The optical fiber connection method according to any one of the above. A ferrule for holding a plurality of optical fibers;
A caulking member for applying pressure to the ferrule in a direction perpendicular to or parallel to the axial direction of the optical fiber;
An optical fiber connector comprising:   The optical fiber connector according to claim 18, wherein the ferrule has a concavo-convex portion that bites into the coating of the optical fiber.   20. The optical fiber connector according to claim 18 or 19, wherein the ferrule is provided with an injection hole for injecting a refractive index matching agent.

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