JP2017173539A - Optical connector and optical coupling structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical connector and optical coupling structure for accurately adjusting a gap between tip end faces of optical fibers.SOLUTION: An optical connector 1 according to an embodiment comprises: an optical fiber; a ferrule 2 provided with a ferrule end face 2a that faces a mating connector and configured to hold the optical fiber; and a spacer 3 disposed on the ferrule end face 2a and designed to define a gap between the ferrule end face 2a and the mating connector. A tip end face of the optical fiber is exposed at the ferrule end face 2a, and directions normal to the tip end face of the optical fiber and to the ferrule end face 2a are at angles with an optical axis direction of the optical fiber. The spacer 3 has an opening 3b for passing a light path extending from the tip end face of the optical fiber, and comprises a first area R1 bonded to the ferrule end face 2a and a second area R2 that is in contact with but not bonded to the ferrule end face 2a.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an optical connector and an optical coupling structure.

  Non-Patent Document 1 discloses a ferrule used for an optical connector that connects multi-core optical fibers. The ferrule has a plurality of holes for holding a plurality of optical fibers, and a guide hole into which a positioning guide pin is inserted. By inserting a guide pin into the guide hole, the ferrule is accurately positioned.

S. Nagasawa et al., “A high-performancesingle-mode multifiber connector using oblique and direct endface contactbetween multiple fibers arranged in a plastic ferrule,” IEEE Photonics Technol Letters, vol. 3, no. 10, pp. 937-939 ( 1991)

  A PC (Physical Contact) method is generally known as a method for connecting connectors between optical fibers. FIG. 8A is a side sectional view showing an example of the structure of a PC type ferrule. The ferrule 100 has a hole 102 for holding the optical fiber 120 on the central axis. The optical fiber 120 is inserted through the hole 102. In this PC method, the optical fibers 120 are optically coupled to each other by pressing the distal end surface of the optical fiber 120 in physical contact with the distal end surface of the optical fiber 120 of the mating connector. This method is mainly used when connecting single optical fibers.

  However, the above method has the following problems. If the connection is made with foreign matter attached to the ferrule end face 104, the foreign matter comes into close contact with the ferrule end face 104 due to the pressing force. In order to remove the adhered foreign matter, it is necessary to use a contact-type cleaner, and in order to prevent the foreign matter from sticking, it is necessary to frequently perform cleaning. In the case of a multi-core ferrule that connects a plurality of optical fibers 120 at the same time, a predetermined pressing force is required for each optical fiber 120. Therefore, the greater the number of optical fibers 120, the greater the force required for connection. It becomes.

  For example, as shown in FIG. 8B, a structure in which a gap is provided between the front end surfaces 121 of the two optical fibers 120 connected to each other is conceivable. However, in the structure in which the gap is provided between the front end surfaces 121, the light coupling state can be changed depending on the length of the gap. Therefore, the gap needs to be adjusted with high accuracy.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide an optical connector and an optical coupling structure that can adjust the distance between the end faces of an optical fiber with high accuracy.

  In order to solve the above-described problems, an optical connector according to an embodiment of the present invention includes an optical fiber, a ferrule end face that faces the mating connector, and a ferrule that holds the optical fiber, and is provided on the ferrule end face. Spacers that define the distance between the ferrule end face and the mating connector, and the front end face of the optical fiber is exposed at the ferrule end face, and the normal direction of each of the front end face of the optical fiber and the ferrule end face is The spacer is inclined with respect to the optical axis direction of the optical fiber, the spacer has an opening through which an optical path extending from the front end surface of the optical fiber passes, the spacer includes a first region joined to the ferrule end surface, and the ferrule end surface And a second region that is not joined to the ferrule end face.

  An optical coupling structure according to an embodiment of the present invention includes first and second optical connectors that are connected to each other. The first and second optical connectors have an optical fiber, a ferrule end face, and an optical fiber. The ferrule end face of the first optical connector and the ferrule end face of the second optical connector are opposed to each other, and each of the first and second optical connectors has an optical fiber at the ferrule end face. The front end surface is exposed, and in the cross section along the optical axis of the optical fiber, the normal directions of the front end surface and the ferrule end surface of the optical fiber are inclined with respect to the optical axis direction of the optical fiber. A spacer that defines a distance between the ferrule end face of the first optical connector and the ferrule end face of the second optical connector, and the first optical connector and the second optical connector. The spacer further includes a guide pin for fixing the pair position, and the spacer has an opening through which an optical path extending between the optical fiber tip surface of the first optical connector and the optical fiber tip surface of the second optical connector passes. The spacer includes a first region joined to one of the ferrule end face of the first optical connector and the ferrule end face of the second optical connector, the ferrule end face of the first optical connector, and the second optical connector. And a second region that is not joined to either the ferrule end surface of the first optical connector or the ferrule end surface of the second optical connector.

  ADVANTAGE OF THE INVENTION According to this invention, adjustment of the space | interval between the front end surfaces of an optical fiber can be performed with high precision.

FIG. 1 is a perspective view showing an optical connector according to an embodiment of the present invention. FIG. 2 is a side sectional view showing a ferrule and guide pins of the optical connector of FIG. FIG. 3 is a front view showing a ferrule end face and a spacer of the optical connector of FIG. FIG. 4 is a side sectional view showing an optical coupling structure constituted by an optical connector and a mating connector according to an embodiment. FIG. 5 is an enlarged side cross-sectional view showing a portion D in FIG. Fig.6 (a) is a side view which shows the method of grind | polishing a ferrule end surface and an optical fiber. FIG. 6B is an enlarged side sectional view showing the ferrule end face and the end face of the optical fiber. FIG. 7A is a side sectional view showing an operation of joining a spacer to the ferrule end face of the optical connector. FIG. 7B is a side sectional view schematically showing a state in which a spacer is bonded to the ferrule end face. 8A and 8B are diagrams schematically showing a conventional optical coupling structure.

[Description of Embodiment of Present Invention]
First, the contents of the embodiment of the present invention will be listed and described. An optical connector according to an embodiment of the present invention includes an optical fiber, a ferrule end face that faces the counterpart connector, a ferrule that holds the optical fiber, a ferrule end face and the counterpart connector provided on the ferrule end face. A front end face of the optical fiber is exposed at the ferrule end face, and the normal direction of the end face of the optical fiber and the end face of the ferrule is relative to the optical axis direction of the optical fiber. The spacer is inclined and has an opening through which an optical path extending from the front end face of the optical fiber passes. The spacer contacts the ferrule end face and the first area joined to the ferrule end face and is joined to the ferrule end face. A second region that is not.

  An optical coupling structure according to an embodiment of the present invention includes first and second optical connectors that are connected to each other. The first and second optical connectors have an optical fiber, a ferrule end face, and an optical fiber. The ferrule end face of the first optical connector and the ferrule end face of the second optical connector are opposed to each other, and each of the first and second optical connectors has an optical fiber at the ferrule end face. The front end surface is exposed, and in the cross section along the optical axis of the optical fiber, the normal directions of the front end surface and the ferrule end surface of the optical fiber are inclined with respect to the optical axis direction of the optical fiber. A spacer that defines a distance between the ferrule end face of the first optical connector and the ferrule end face of the second optical connector, and the first optical connector and the second optical connector. The spacer further includes a guide pin for fixing the pair position, and the spacer has an opening through which an optical path extending between the optical fiber tip surface of the first optical connector and the optical fiber tip surface of the second optical connector passes. The spacer includes a first region joined to one of the ferrule end face of the first optical connector and the ferrule end face of the second optical connector, the ferrule end face of the first optical connector, and the second optical connector. And a second region that is not joined to either the ferrule end surface of the first optical connector or the ferrule end surface of the second optical connector.

  In the optical connector described above, a spacer that defines the distance from the mating connector is provided on the ferrule end face. Similarly, in the optical coupling structure described above, a spacer is provided that defines the distance between the ferrule end face of the first optical connector and the ferrule end face of the second optical connector. Thereby, a predetermined space can be easily provided between the ferrule end face and the mating connector (or between the ferrule end faces of the first and second optical connectors). Here, if all of the spacer surfaces that contact the ferrule end surface are bonded to the ferrule end surface, the thickness of the spacer decreases as the spacer is bonded to the ferrule end surface, and the desired interval is defined by the decrease in the thickness. There is concern that will not be. However, in the optical connector and the optical coupling structure described above, since the spacer has the second region that is in contact with the ferrule end surface and is not joined to the ferrule end surface, the thickness of the spacer is ensured in the second region that is not joined. Can do. Therefore, by interposing this spacer between the ferrule end faces, the distance between the end faces of the optical fibers exposed at the ferrule end faces can be reliably defined to a desired distance. Therefore, it is possible to adjust the distance between the end faces of the optical fibers with high accuracy.

  In addition, the second region may include at least a part of the inner edge that forms the opening of the spacer. Further, the second region may include all of the inner edge that forms the opening of the spacer. In this case, since the thickness of the spacer can be ensured at the inner edge forming the opening, a desired interval can be ensured at the position of the opening of the spacer.

  Further, the outer dimension of the spacer may be equal to or smaller than the outer dimension of the ferrule end face. In this case, since the spacer is within the region of the ferrule end face, it is possible to suppress the spacer from protruding from the ferrule end face. Therefore, it is possible to avoid the problem that the protruding spacer is caught around and the spacer is peeled off.

  Further, the thickness of the spacer may be not less than 5 μm and not more than 30 μm. Thus, by setting the thickness of the spacer to 5 μm or more and 30 μm or less, an optical coupling structure in which multiple reflection of light between the end faces of the optical fiber is suppressed is realized. Further, by defining the distance between the two end faces of the two optical fibers by such a thin spacer, the distance between the two end faces is shortened, and the coupling loss is low despite the configuration without using a lens. Thus, these optical fibers can be connected to each other.

  Further, the optical connector may include a spring that biases the ferrule in the direction of pressing the mating connector, and the pressing force of the spring may be 2N or more and 6N or less. By setting the pressing force of the spring to 2N or more, the optical connector can be reliably connected to the mating connector. Moreover, the slip which arises in a ferrule end surface can be suppressed by making the pressing force of a spring 6N or less. Furthermore, by setting the spring pressing force to 6 N or less, it is possible to suppress the ferrule or the spacer from being elastically deformed by an excessive pressing force, thereby changing the interval defined by the spacer.

  Further, the inclination angle in the normal direction of the front end face of the optical fiber with respect to the optical axis direction and the inclination angle in the normal direction of the ferrule end face with respect to the optical axis direction may both be 10 ° or more and 20 ° or less. Thus, by setting the inclination angle of each normal direction with respect to the optical axis direction to 10 ° or more, the return light from the tip surface of the optical fiber toward the mating connector can be greatly separated from the optical axis of the optical fiber. Therefore, it is possible to make it difficult for the return light to enter the optical fiber of the mating connector, and to suppress multiple reflections of light between the front end surfaces of the optical fiber. Moreover, the difference of the coupling strength between the several polarization components of light can be suppressed by making the inclination-angle of each normal line direction with respect to an optical axis direction into 20 degrees or less.

  Further, the protruding amount of the optical fiber from the ferrule end face may be 1 μm or less. Thus, by controlling the protruding amount of the optical fiber to 1 μm or less, it is possible to manage the interval between the end faces of the optical fiber with high accuracy.

  Further, the radius of curvature of the ferrule end face may be 50 mm or more. Thus, by setting the radius of curvature of the ferrule end face to 50 mm or more and making the ferrule end face close to a flat surface, the distance between the end faces of the optical fibers can be managed with high accuracy.

  In the optical coupling structure described above, the position of the optical fiber of the first optical connector and the position of the optical fiber of the second optical connector intersect the optical axis in a cross section along the optical axis of the optical fiber. The directions may be offset from each other. In this optical coupling structure, since the normal direction of the tip surface of the optical fiber is inclined with respect to the optical axis direction of the optical fiber, the optical path extending from the tip surface of the optical fiber by the refraction at the tip surface is the optical fiber. Tilt in a direction that intersects the optical axis. Even in such a configuration, the position of the optical fiber of the first optical connector and the position of the optical fiber of the second optical connector are shifted from each other in the direction intersecting the optical axis. The optical fiber of the optical connector and the optical fiber of the second optical connector can be suitably optically coupled.

[Details of the embodiment of the present invention]
Specific examples of the optical connector and the optical coupling structure according to the embodiment of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and is intended that all the changes within the meaning and range equivalent to the claim are included. In the following description, in the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a perspective view showing an optical connector 1 according to an embodiment of the present invention. FIG. 2 is a side sectional view schematically showing the ferrule 2 and the spacer 3 of the optical connector 1. As shown in FIGS. 1 and 2, the optical connector 1 includes a ferrule 2 and a spacer 3. The ferrule 2 has a rectangular parallelepiped appearance, and is made of, for example, a resin such as polyphenylene sulfide (PPS) containing glass particles.

  The ferrule 2 is connected to the mating connector in the connection direction A1. The ferrule 2 has a ferrule end face 2a provided on one end side in the connection direction A1 and facing the mating connector, and a rear end face 2b provided on the other end side in the connection direction A1. The ferrule 2 has a side surface 2d extending along the connection direction A1, a bottom surface 2e, and an upper surface 2f. The rear end face 2b is formed with an introduction hole for receiving a plurality of optical fibers collectively. For example, the plurality of optical fibers are introduced in the form of a 0.25 mm strand, a 0.9 mm core, a tape core, or the like.

  The ferrule 2 further includes a plurality of optical fiber holding holes 2c, and an optical fiber 5 is inserted into each optical fiber holding hole 2c. The optical fiber 5 is, for example, a single mode fiber. The plurality of optical fiber holding holes 2c penetrate from the introduction hole to the ferrule end surface 2a, and the front end surface 5a of each optical fiber 5 is exposed at the ferrule end surface 2a.

  Each optical fiber holding hole 2c extends in the connection direction A1, and the center axis direction of each optical fiber holding hole 2c and the optical axis direction of the optical fiber 5 both coincide with the connection direction A1. The front end surfaces 5a of the plurality of optical fibers 5 are arranged in a line along the direction A2 intersecting the connection direction A1 on the ferrule end surface 2a. A set of a plurality of tip surfaces 5a arranged in a line is arranged in two stages in a direction A3 intersecting the direction A2. The positions in the direction A3 of the set of the front end surfaces 5a arranged in a line are displaced from each other vertically relative to the center position of the ferrule end surface 2a in the direction A3. The direction A2 is, for example, a direction orthogonal to the connection direction A1 and parallel to the ferrule end surface 2a and the upper surface 2f. The direction A3 is a direction orthogonal to the plane extending in the connection direction A1 and the direction A2, for example.

  The optical connector 1 further includes a pair of guide pins 6a and 6b. The pair of guide pins 6a and 6b are inserted into the guide holes 2g and 2h of the ferrule 2, respectively, and project from the ferrule end surface 2a in the connection direction A1. The guide pins 6 a and 6 b are inserted into the guide holes of the ferrule of the mating connector connected to the ferrule 2. The guide pins 6a and 6b fix the relative positions of the ferrule 2 and the ferrule of the mating connector. The pair of guide pins 6a and 6b are arranged along the direction A2, and are provided at positions sandwiching the plurality of optical fibers 5 (in other words, both sides in the row direction A2 on the distal end surface 5a of the optical fibers 5). .

  The spacer 3 is a member formed in a film shape (thin film shape). The spacer 3 is disposed on the ferrule end surface 2a. The spacer 3 has a facing surface 3a facing the ferrule end surface 2a, and at least a part of the facing surface 3a is in contact with the ferrule end surface 2a. The spacer 3 is sandwiched between the ferrule end surface 2a and the ferrule end surface of the mating connector, thereby defining a distance between the ferrule end surface 2a and the ferrule end surface of the mating connector.

  FIG. 3 is a front view showing a state in which the spacer 3 and the ferrule end surface 2a are viewed from the connection direction A1. As shown in FIG. 3, the spacer 3 has an opening 3b that exposes the ferrule end face 2a. The openings 3b are used to pass through a plurality of optical paths extending between the front end surfaces 5a of the plurality of optical fibers 5 and the respective front end surfaces of the plurality of optical fibers of the mating connector. Expose 5a. The opening 3b projects the guide pins 6a and 6b. That is, the opening 3b is formed in a rectangular shape surrounding the guide pins 6a and 6b and the front end surfaces 5a of the plurality of optical fibers 5 when viewed from the axial direction of the guide pins 6a and 6b (that is, the connection direction A1). As an example, the opening 3b is formed with the direction A2 as a longitudinal direction. For example, the length of the opening 3b in the direction A2 is 5.31 mm, and the width of the opening 3b in the direction A3 intersecting the direction A2 is 0.71 mm.

  The outer dimension of the spacer 3 is equal to or smaller than the outer dimension of the ferrule end surface 2a. That is, when the spacer 3 and the ferrule end surface 2a are viewed from the connection direction A1, the outer edge of the spacer 3 is located inside the outer edge of the ferrule end surface 2a. Thereby, peeling of the spacer 3 resulting from catching to the peripheral part of the spacer 3 is suppressed. The thickness of the spacer 3 in the connection direction A1 is, for example, not less than 5 μm and not more than 30 μm, and is 20 μm as an example. Thereby, the space | interval of the ferrule end surface 2a and the ferrule end surface of the other party connector is prescribed | regulated to 5 micrometers or more and 30 micrometers or less (for example, 20 micrometers).

  As a material of the spacer 3, for example, a resin such as PPS is used, and the same material as that of the ferrule 2 is used. Further, the facing surface 3a of the spacer 3 has a first region R1 joined to the ferrule end surface 2a and a second region R2 not joined to the ferrule end surface 2a. The joining of the spacer 3 and the ferrule end surface 2a is performed by, for example, welding (laser welding or the like). As described above, when the material of the spacer 3 and the material of the ferrule 2 are the same, the linear expansion coefficient of the spacer 3 and the linear expansion coefficient of the ferrule 2 are approximately equal to each other. However, there is no fear of peeling from the ferrule 2, and the reliability by welding is high.

  In the first region R1 of the spacer 3, the facing surface 3a and the ferrule end surface 2a are welded. On the other hand, in the second region R2 of the spacer 3, the facing surface 3a and the ferrule end surface 2a are not welded to each other. That is, in the second region R2, the facing surface 3a and the ferrule end surface 2a only contact each other. The second region R2 is, for example, a region including the opening 3b of the spacer 3, and has a rectangular shape extending in the direction A2 and the direction A3. The first region R1 is located outside the second region R2, and has a rectangular shape surrounding the second region R2.

  FIG. 4 is a side sectional view showing the optical coupling structure 10 including the optical connector 1 of the present embodiment. The optical connector 1 further includes a pin keeper 7 that holds the guide pins 6a and 6b, a spring 8 that urges the pin keeper 7 and the ferrule 2 in the connection direction A1, and a housing 9 that houses the spring 8. The pin keeper 7 includes a pair of holding holes 7a for holding the guide pins 6a and 6b.

  The spring 8 is provided on the opposite side of the ferrule 2 with the pin keeper 7 interposed therebetween and is accommodated in the housing 9. One end of the spring 8 is supported inside the housing 9, and the other end of the spring 8 is in contact with the pin keeper 7. The spring 8 presses the ferrule 2 against the mating connector 11. The spring constant of the spring 8 is a value at which the pressing force by the spring 8 is 2N or more and 6N or less.

  The optical coupling structure 10 includes an optical connector 1 (first optical connector) and a mating connector 11 (second optical connector). The mating connector 11 includes a ferrule 12 and a plurality of optical fibers 15. In the optical coupling structure 10, the ferrule end surface 2a of the ferrule 2 of the optical connector 1 and the ferrule end surface 12a of the ferrule 12 of the mating connector 11 face each other in the connection direction A1. The ferrule 12 has guide holes 12g and 12h into which the guide pins 6a and 6b are inserted from the ferrule end face 12a.

  The mating connector 11 includes, for example, a pin keeper 17, a spring 18, and a housing 19. The configurations of the pin keeper 17, the spring 18, and the housing 19 are the configurations of the pin keeper 7, the spring 8, and the housing 9 of the optical connector 1. Can be the same. In the optical coupling structure 10, the guide pins 6 a and 6 b inserted through the ferrule 2 of the optical connector 1 are inserted into the guide holes 12 g and 12 h of the ferrule 12 of the mating connector 11, respectively. The mating connector 11 is connected in the connection direction A1.

  As described above, the spacer 3 is sandwiched between the ferrule end surface 2a of the optical connector 1 and the ferrule end surface 12a of the mating connector 11, thereby defining the distance between the ferrule end surfaces 2a and 12a. Therefore, the spacer 3 abuts on the ferrule end surface 12 a of the mating connector 11. Then, the optical fiber 5 of the optical connector 1 and the optical fiber 15 of the mating connector 11 are optically coupled through the opening 3 b of the spacer 3.

  FIG. 5 is an enlarged cross-sectional view showing a portion D shown in FIG. As shown in FIG. 5, the front end surfaces 5a and 15a of the optical fibers 5 and 15 are exposed at the ferrule end surfaces 2a and 12a, respectively, and are preferably flush with the ferrule end surfaces 2a and 12a. In the cross section along the optical axis of the optical fibers 5 and 15, the normal direction V1 of the end faces 5a and 15a of the optical fibers 5 and 15 is the central axis direction of the optical fiber holding holes 2c and 12c, that is, the optical fibers 5 and 15. Is inclined with respect to the optical axis direction V2.

  Assuming that the inclination angle in the normal direction V1 with respect to the optical axis direction V2 is the inclination angle θ, the inclination angle θ is, for example, not less than 10 ° and not more than 20 °, and more specifically, for example, 12 °. Further, this inclination angle θ coincides with the inclination angle of the end faces 5a, 15a with respect to the plane orthogonal to the optical axis of the optical fibers 5, 15.

  In the present embodiment, the normal direction of the ferrule end faces 2a and 12a coincides with the normal direction V1 of the tip faces 5a and 15a. The optical path L1 of the light emitted from the tip surfaces 5a and 15a is refracted in the direction opposite to the direction of inclination of the tip surfaces 5a and 15a at the tip surfaces 5a and 15a. Accordingly, the central axis of the optical fiber 5 of the optical connector 1 and the central axis of the optical fiber 15 of the mating connector 11 are shifted from each other in the refraction direction (direction A3). The amount of deviation in this direction A3 is, for example, 1 μm or more. Further, only the gap K is provided between the distal end surface 5a of the optical fiber 5 of the optical connector 1 and the distal end surface 15a of the optical fiber 15 of the counterpart connector 11 without using an optical element such as a lens or a refractive index matching agent. It is optically coupled directly. The interval K is filled with air, for example.

  Further, in the optical connector 1, after the optical fiber 5 is passed through and held in the optical fiber holding hole 2c of the ferrule 2, the front end surface 5a and the ferrule end surface 2a of the optical fiber 5 are polished, and the ferrule end surface 2a has a spacer. The optical connector 1 is completed by joining 3. Below, the grinding | polishing method of the front end surface 5a and the ferrule end surface 2a and the joining method of the spacer 3 to the ferrule end surface 2a are demonstrated among the manufacturing methods of the optical connector 1. FIG.

  FIG. 6A is a side view schematically showing an apparatus for polishing the ferrule end face 2a and the front end face 5a of the optical fiber 5, and FIG. 6B is an enlarged view of the ferrule end face 2a and the front end face 5a of the optical fiber 5. It is a sectional side view which shows typically the state which carried out. As shown in FIG. 6A, the apparatus 20 for polishing the ferrule end face 2a and the tip end face 5a includes a polishing paper 21 on which the ferrule end face 2a and the tip end face 5a are rubbed, and a plate member 22 that supports the polishing paper 21. Prepare. In this apparatus 20, the ferrule 2 is held, and polishing is performed by rubbing the held ferrule end surface 2 a of the ferrule 2 and the front end surface 5 a of the optical fiber 5 along the polishing paper 21.

  By the way, it is preferable that the ferrule end surface 2a and the front end surface 5a are close to a plane. However, in practice, as shown in an enlarged view in FIG. 6B, the ferrule end surface 2a and the front end surface 5a are slightly curved in the process of being rubbed by polishing. Further, the front end surface 5a slightly protrudes from the ferrule end surface 2a. However, in the present embodiment, the curvatures of the ferrule end surface 2a and the front end surface 5a are suppressed, and the protrusion amounts P1, P2 of the front end surface 5a from the ferrule end surface 2a are suppressed.

  For example, when buffing is performed using a soft member as the polishing paper 21 and the plate member 22, an event may occur in which only the ferrule 2 is scraped without scraping the hard optical fiber 5 during polishing. In the present embodiment, in order to avoid this phenomenon, polishing is performed using a hard polishing paper 21 and a hard plate material 22 such as using a polishing paper 21 made of diamond. Thereby, since both the ferrule 2 and the optical fiber 5 are shaved, the protrusion amounts P1 and P2 of the front end surface 5a from the ferrule end surface 2a are 1 μm or less. And the dispersion | variation in several protrusion amount P1, P2 is also suppressed to 1 micrometer or less.

  Further, the ferrule 2 is pressed and polished so that the ferrule 2 moves in parallel along the polishing paper 21 on the polishing paper 21, whereby the ferrule end face 2a of the ferrule 2 is evenly shaved, whereby the ferrule end face 2a Further, polishing is performed while maintaining the state where the tip surface 5a is close to a flat surface, and the radius of curvature of the ferrule end surface 2a is, for example, 50 mm or more, more preferably 100 mm or more.

  FIG. 7A is a side sectional view schematically showing a method of joining the spacer 3 to the ferrule end face 2a, and FIG. 7B is a side sectional view schematically showing a state in which the spacer 3 is joined. . As shown in FIG. 7A, in the operation of joining the spacer 3, for example, the plate-shaped jig 31, the elastic jig 32, the optical mask 33, and the plate-shaped jig 34 are placed on the spacer 3 in this order.

  Then, the laser beam S is applied from above the plate-shaped jig 34 (out-of-plane direction of the plate-shaped jig 34) while suppressing the displacement of the spacer 3 by pressing the spacer 3 with the plate-shaped jig 34. Irradiation welds the spacer 3 and the ferrule end face 2a to each other. At this time, the elastic jig 32 absorbs the relative inclination between the plate-like jig 31 and the plate-like jig 34. The plate-shaped jig 31, the elastic jig 32, and the plate-shaped jig 34 are configured by members that transmit at least the wavelength of the laser beam S. In one example, the plate-shaped jig 31 is an acrylic plate having a thickness of 2 mm, the elastic jig 32 is a silicone film having a thickness of 2 mm, and the plate-shaped jig 34 is an acrylic plate having a thickness of 10 mm.

  The optical mask 33 protects the second region R2 including the opening 3b of the spacer 3 from the laser light S. Thereby, the laser beam S is not irradiated on the second region R2, but only on the first region R1. In the first region R1, the laser beam S passes through the spacer 3 and reaches the ferrule end surface 2a, and welds the ferrule end surface 2a and the facing surface 3a of the spacer 3. At this time, since the ferrule end surface 2a and the facing surface 3a are melted by the laser light S, the thickness of the spacer 3 is slightly reduced (for example, about several μm) in the first region R1. However, in the present embodiment, since the second region R2 that does not melt is provided, the initial thickness of the spacer 3 is secured and the interval K is reliably defined by the second region R2.

  As described above, in the optical connector 1, the spacer 3 that defines the interval K with the mating connector 11 is provided on the ferrule end surface 2 a. Similarly, in the optical coupling structure 10, a spacer 3 that defines a distance K between the ferrule end surface 2 a of the optical connector 1 and the ferrule end surface 12 a of the mating connector 11 is provided. Thereby, the predetermined space | interval K can be easily provided between the ferrule end surface 2a and the other party connector 11 (or between the ferrule end surface 2a and the ferrule end surface 12a).

  Therefore, the non-contact optical coupling structure 10 can be realized, and the ferrule end surfaces 2a and 12a can be easily cleaned (or need not be cleaned). And even if the optical connector 1 is repeatedly attached and detached, adhesion of foreign matters to the ferrule end faces 2a and 12a and damage to the ferrule end faces 2a and 12a do not occur, so that durability against repeated attachment and detachment can be enhanced.

  Moreover, in the optical connector 1 and the optical coupling structure 10, unlike the PC system, a plurality of optical fibers 5 and 15 can be connected simultaneously without requiring a large force for connection. Further, since the optical fiber holding holes 2c and 12c are opened at the ferrule end surfaces 2a and 12a, the front end surfaces 5a and 15a of the optical fibers 5 and 15 are exposed at the ferrule end surfaces 2a and 12a, and the optical fiber of the mating connector 11 is used. 15 is optically coupled without a lens. Therefore, the number of optical members present in the optical path can be reduced, and optical connection loss can be suppressed.

  By the way, if all of the spacer surfaces that contact the ferrule end surface are bonded to the ferrule end surface, the spacer thickness decreases as the spacer is bonded to the ferrule end surface, and the desired interval K is defined by the decrease in the thickness. There is concern that will not be. However, in the optical connector 1 and the optical coupling structure 10, since the spacer 3 contacts the ferrule end surface 2a and has the second region R2 that is not joined to the ferrule end surface 2a, the spacer 3 is in the second region R2 that is not joined. Can be ensured. Therefore, by interposing the spacer 3 between the ferrule end faces 2a and 12a, the distance K between the end faces 5a and 15a of the optical fibers 5 and 15 exposed on the ferrule end faces 2a and 12a can be adjusted with high accuracy. . Further, the second region R2 that is in contact with the ferrule end surfaces 2a and 12a and is not joined to the ferrule end surfaces 2a and 12a includes an inner edge that forms the opening 3b of the spacer 3, and therefore, at the position of the opening 3b of the spacer 3. A desired interval K can be secured.

  The outer dimension of the spacer 3 is equal to or smaller than the outer dimension of the ferrule end surface 2a. Therefore, since the spacer 3 fits in the area | region of the ferrule end surface 2a, it can suppress that the spacer 3 protrudes from the ferrule end surface 2a. Therefore, it is possible to avoid the problem that the protruding spacer 3 is caught around and the spacer 3 is peeled off.

  The thickness of the spacer 3 is not less than 5 μm and not more than 30 μm. Thereby, the optical coupling structure 10 in which multiple reflection of light between the front end surfaces 5a and 15a of the optical fibers 5 and 15 is suppressed is realized. Furthermore, the distance K between the two end surfaces 5a and 15a is shortened by using the thin spacer 3 so that the distance between the two end surfaces 5a and 15a of the two optical fibers 5 and 15 is reduced. Despite the configuration, these optical fibers 5 and 15 can be connected to each other with a low coupling loss.

  Further, the optical connector 1 includes a spring 8 that biases the ferrule 2 in a direction in which the counterpart connector 11 is pressed, and the pressing force of the spring 8 is 2N or more and 6N or less. By setting the pressing force of the spring 8 to 2N or more, each of the guide pins 6a and 6b can be surely inserted into the guide holes 12g and 12h, and the optical connector 1 can be reliably connected to the mating connector 11. Moreover, the slip which arises in the ferrule end surface 2a can be suppressed by making the pressing force of the spring 8 6N or less. Furthermore, by setting the pressing force of the spring 8 to 6 N or less, the ferrule 2 or the spacer 3 is elastically deformed by an excessive pressing force, thereby suppressing the interval K defined by the spacer 3 from changing. You can also.

  The inclination angle θ in the normal direction V1 of the tip surface 5a of the optical fiber 5 with respect to the optical axis direction V2 and the inclination angle θ in the normal direction V1 of the ferrule end surface 2a with respect to the optical axis direction V2 are both 10 ° or more and 20 ° or less. Thus, by setting the inclination angle θ in the normal direction V1 with respect to the optical axis direction V2 to 10 ° or more, the return light from the distal end surface 5a of the optical fiber 5 toward the counterpart connector 11 is transmitted from the optical axis of the optical fiber 15. Can be separated greatly. Therefore, it is possible to make it difficult for the return light to enter the optical fiber 15 of the counterpart connector 11, and to suppress multiple reflection of light between the front end surfaces 5 a and 15 a of the optical fibers 5 and 15. In addition, by setting the inclination angle θ in the normal direction V1 with respect to the optical axis direction V2 to 20 ° or less, it is possible to suppress a difference in coupling strength between a plurality of polarization components of light.

  Further, the protruding amounts P1 and P2 of the optical fiber 5 from the ferrule end face 2a are 1 μm or less. Thus, by controlling the protruding amounts P1 and P2 of the optical fiber 5 to 1 μm or less, the distance K between the front end surfaces 5a and 15a of the optical fibers 5 and 15 can be managed with high accuracy.

  Moreover, the curvature radius of the ferrule end surface 2a is 50 mm or more. Thus, by setting the radius of curvature of the ferrule end face 2a to 50 mm or more and making the ferrule end face 2a close to a flat surface, the distance K between the end faces 5a, 15a of the optical fibers 5, 15 can be managed with high accuracy.

  In the optical coupling structure 10, the position of the optical fiber 5 of the optical connector 1 and the position of the optical fiber 15 of the mating connector 11 intersect the optical axis in the cross section along the optical axis of the optical fibers 5 and 15. Are shifted from each other in the direction A3. In this optical coupling structure 10, since the normal direction V1 of the front end surfaces 5a, 15a of the optical fibers 5, 15 is inclined with respect to the optical axis direction V2 of the optical fibers 5, 15, the front end surfaces 5a, 15a Due to the refraction, the optical path L1 extending from the front end surfaces 5a and 15a of the optical fibers 5 and 15 is inclined in the direction A3 intersecting the optical axis of the optical fibers 5 and 15. Even in such a configuration, the position of the optical fiber 5 of the optical connector 1 and the position of the optical fiber 15 of the counterpart connector 11 are shifted from each other in the direction A3 intersecting the optical axis. The optical fiber 5 and the optical fiber 15 of the mating connector 11 can be suitably optically coupled.

  The optical connector and the optical coupling structure according to the present invention are not limited to the above-described embodiments, and various other modifications are possible. For example, in the above-described embodiment, the gap K between the ferrule end faces 2a and 12a is filled with air. However, if the medium has a constant refractive index, the gap K may be filled with a medium other than air. Moreover, the structure of the apparatus which grind | polishes the ferrule end surface and the front end surface of an optical fiber can be changed suitably. Furthermore, the member used when joining the spacer to the ferrule end face is not limited to the above-described plate-shaped jig 31, elastic jig 32, optical mask 33, and plate-shaped jig 34, and can be changed as appropriate.

  In the above-described embodiment, the example in which the inner edge forming the opening 3b of the spacer 3 is rectangular has been described. However, the shape and size of the inner edge forming the opening 3b can be appropriately changed. Further, in the above-described embodiment, the example in which the second region R2 that is not joined to the ferrule end surfaces 2a and 12a of the facing surface 3a of the spacer 3 includes the inner edge that forms the opening 3b of the spacer 3 has been described. The region R2 may be a region including only a part of the inner edge, or may be a region outside the opening 3b without including the inner edge. As described above, the location, size, and shape of the second region R2 that is not joined to the ferrule end surfaces 2a and 12a and the first region R1 that is joined to the ferrule end surfaces 2a and 12a can be appropriately changed.

  Further, the springs 8 and 18 can be omitted from either the optical connector 1 or the mating connector 11, and the configurations of the ferrule, pin keeper, spring, and housing of the optical connector 1 and the mating connector 11 are changed as appropriate. Is possible. Further, the number, shape and size of the guide pins 6a and 6b can be changed as appropriate. Moreover, although the present invention is applied to the multi-core ferrule in the above-described embodiment, it can also be applied to a single-core ferrule.

DESCRIPTION OF SYMBOLS 1 ... Optical connector (1st optical connector), 2,12 ... Ferrule, 2a, 12a ... Ferrule end surface, 2b ... Rear end surface, 2c, 12c ... Optical fiber holding hole, 2d ... Side surface, 2e ... Bottom surface, 2f ... Top surface 2g, 2h, 12g, 12h ... guide hole, 3 ... spacer, 3a ... facing surface, 3b ... opening, 5,15 ... optical fiber, 5a, 15a ... tip surface, 6a, 6b ... guide pin, 7, 17 ... Pin keeper, 7a ... holding hole, 8, 18 ... spring, 9, 19 ... housing, 10 ... optical coupling structure, 11 ... mating connector (second optical connector), 20 ... device, 21 ... abrasive paper, 22 ... Plate material 31, 34 ... Plate-shaped jig, 32 ... Elastic jig, 33 ... Optical mask, A1 ... Connection direction, A2, A3 ... Direction, K ... Distance, L1 ... Optical path, P1, P2 ... Projection amount, R1 ... 1st region, R2 ... 2nd region, S ... Light, V1 ... normal direction, V2 ... optical axis, theta ... tilt angle.

Claims (11)

Optical fiber,
A ferrule having a ferrule end face facing the mating connector, and holding the optical fiber;
A spacer provided on the ferrule end face and defining a distance between the ferrule end face and the mating connector;
The end face of the optical fiber is exposed at the ferrule end face,
The normal directions of the tip surface and the ferrule end surface of the optical fiber are inclined with respect to the optical axis direction of the optical fiber,
The spacer has an opening through which an optical path extending from the tip surface of the optical fiber passes;
The spacer has a first region joined to the ferrule end surface and a second region that contacts the ferrule end surface and is not joined to the ferrule end surface.
Optical connector. The second region includes at least a part of an inner edge forming the opening of the spacer.
The optical connector according to claim 1. The second region includes all of the inner edge forming the opening of the spacer.
The optical connector according to claim 1. The outer dimension of the spacer is equal to or smaller than the outer dimension of the ferrule end face.
The optical connector as described in any one of Claims 1-3. The spacer has a thickness of 5 μm or more and 30 μm or less.
The optical connector as described in any one of Claims 1-4. A spring for urging the ferrule in the direction of pressing the mating connector;
The pressing force of the spring is 2N or more and 6N or less,
The optical connector as described in any one of Claims 1-5. The tilt angle in the normal direction of the tip surface of the optical fiber with respect to the optical axis direction and the tilt angle in the normal direction of the ferrule end surface with respect to the optical axis direction are both 10 ° or more and 20 ° or less.
The optical connector as described in any one of Claims 1-6. The amount of protrusion of the optical fiber from the ferrule end face is 1 μm or less,
The optical connector as described in any one of Claims 1-7. The radius of curvature of the ferrule end face is 50 mm or more,
The optical connector as described in any one of Claims 1-8. Comprising first and second optical connectors connected to each other;
The first and second optical connectors each include an optical fiber and a ferrule having a ferrule end face and holding the optical fiber,
The ferrule end surface of the first optical connector and the ferrule end surface of the second optical connector face each other,
In each of the first and second optical connectors, the end face of the optical fiber is exposed at the ferrule end face,
In the cross section along the optical axis of the optical fiber, the normal directions of the tip surface and the ferrule end surface of the optical fiber are inclined with respect to the optical axis direction of the optical fiber,
A spacer for defining an interval between the ferrule end face of the first optical connector and the ferrule end face of the second optical connector;
A guide pin for fixing a relative position between the first optical connector and the second optical connector;
The spacer has an opening for passing an optical path extending between the tip surface of the optical fiber of the first optical connector and the tip surface of the optical fiber of the second optical connector;
The spacer is
A first region joined to one of the ferrule end face of the first optical connector and the ferrule end face of the second optical connector;
The ferrule end surface of the first optical connector and the ferrule end surface of the second optical connector are in contact with each other, and either the ferrule end surface of the first optical connector or the ferrule end surface of the second optical connector is contacted. A second region that is also not joined,
Optical coupling structure. In the cross section, the position of the optical fiber of the first optical connector and the position of the optical fiber of the second optical connector are shifted from each other in a direction intersecting the optical axis.
The optical coupling structure according to claim 10.

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