JP6554891B2 - Optical connector - Google Patents

Description

  The present invention relates to an optical connector.

  Patent Document 1 discloses a multi-core fiber coupling device. FIG. 9 is a diagram showing the configuration of the coupling device. The coupling device 100 optically couples the multicore fiber 101 and a plurality of single core fibers 102. The coupling device 100 includes a first optical system 103 and a second optical system 104. The first optical system 103 is positioned on the optical axes of a plurality of beams emitted from the multi-core fiber 101, and the optical axes of the beams are different from each other so as to be separated from each other. The second optical system 104 converges the optical axes of the plurality of beams from the first optical system 103 so as to be substantially parallel to each other. For this purpose, the second optical system 104 includes one condenser lens 104a and a plurality of condenser lenses 104b.

JP2013-020227A

  In recent years, for example, in order to reduce the number of optical cables connected to a communication device, it is desired to use a multi-core fiber in which a plurality of cores are arranged inside one clad. When such a multi-core fiber is connected to a communication device, it is required to optically couple a plurality of cores of the multi-core fiber and a plurality of single-core fibers in order to extract signal light propagating through each core. Said patent document 1 is an example of the apparatus used for such a coupling | bonding.

  However, in the coupling device 100 shown in FIG. 9, the optical axis of each beam emitted from the second optical system 104 coincides with the optical axis of the core of the single core fiber 102. The end face of the single core fiber 102 is orthogonal to the optical axis. Accordingly, each beam is reflected at the end face of the single core fiber 102 to become return light, and the reflected return light is coupled to each core of the multicore fiber 101. As a result, the reflected return light enters the communication device on the transmission side, and there is a possibility that the optical characteristics of the signal light are deteriorated.

  As a method for solving the above problem, for example, it is conceivable to process (polish or the like) the end faces of the plurality of single core fibers 102 so as to be inclined with respect to a plane perpendicular to the optical axis. In this way, the reflected light at the end face of the single core fiber 102 deviates from the optical axis and does not enter the core of the multicore fiber 101, so that the reflected return light can be reduced. However, for example, when each end face is polished together in a state where a plurality of single core fibers 102 are bundled, each end face is flush with a plane perpendicular to the optical axis. In such a case, the positions of the end faces in the optical axis direction are shifted from each other, so that the optical path length between each end face and the condensing lens 104b differs for each single core fiber 102. Accordingly, there is a problem that light is incident in a defocused state in at least some of the single core fibers 102, and the coupling loss increases.

  The present invention has been made in view of such problems, and an object thereof is to provide an optical connector capable of suppressing an increase in coupling loss while reducing reflected return light.

  In order to solve the above-described problem, an optical connector according to an embodiment of the present invention includes a plurality of cores, a core of a multicore fiber having a common cladding surrounding the plurality of cores, a single core, and the core. An optical connector that optically couples each core of a plurality of single-core fibers each having a surrounding clad along a certain axis, the optical axes being emitted from the plurality of cores of the multi-core fiber, respectively, parallel to each other A first optical system that receives the plurality of beams and emits the plurality of beams such that the optical axes are inclined with respect to each other, and the plurality of beams that are emitted from the first optical system, And a second optical system that emits the plurality of beams so that the optical axes are parallel to each other, and the optical axes of the plurality of beams incident on the first optical system are: The optical axes of the plurality of beams emitted from the second optical system are inclined with respect to a plane perpendicular to the axis, and the second optical system converts the plurality of beams into the axis line. The light is condensed at different positions in the first direction, which is the stretching direction.

  According to the optical connector of the present invention, it is possible to suppress an increase in coupling loss while reducing reflected return light.

FIG. 1 is a diagram schematically showing a cross section of an optical device including an optical connector according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 and represents an XY cross section of the multicore fiber. FIG. 3 is a front view of the lens array as viewed from the Z direction (single core fiber side). FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3 and represents an XZ cross section of the lens array. FIG. 5 is a perspective view showing a plurality of single core fibers. 6 is a cross-sectional view showing a VI-VI cross section (XY cross section) shown in FIG. FIG. 7 is an enlarged view showing a mode of optical coupling between a plurality of single core fibers and a lens array. FIG. 8 is a diagram schematically showing a cross section of an optical device including an optical connector according to the second embodiment of the present invention. FIG. 9 is a diagram showing the configuration of the coupling device.

[Description of Embodiment of the 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 a multi-core fiber having a plurality of cores and a common cladding surrounding the plurality of cores, and a plurality of single cores each having one core and a cladding surrounding the core. An optical connector that optically couples each core of a core fiber along a certain axis, and receives a plurality of beams having optical axes parallel to each other and emitted from a plurality of cores of the multi-core fiber. A first optical system that emits the plurality of beams so that the axes are inclined to each other, and a plurality of beams that are emitted from the first optical system, the optical axes are directed toward the plurality of cores of the plurality of single-core fibers. A second optical system that emits the plurality of beams so as to be parallel to each other, and the optical axes of the plurality of beams incident on the first optical system are parallel to the axis, and the second light The optical axes of the plurality of beams emitted from the system are inclined with respect to a plane perpendicular to the axis, and the second optical system positions the plurality of beams at positions different from each other in the first direction that is the extending direction of the axis. Condensed respectively.

  In this optical connector, the second optical system condenses each of the plurality of beams at different positions in the first direction. Thereby, even when the positions of the end faces of the plurality of single core fibers in the optical axis direction are shifted from each other, the positions of the condensing points of the beams can be easily aligned with the positions of the end faces. Therefore, an increase in coupling loss between the second optical system and the plurality of single core fibers can be suppressed. In this optical connector, the optical axes of the plurality of beams emitted from the second optical system are inclined with respect to a plane perpendicular to the axis. As a result, each beam can be incident on the end face of each single-core fiber at an appropriate angle. Therefore, the incident angle of each beam on the end face of each single-core fiber can be increased while reducing connection loss. Thus, the reflected return light can be effectively reduced.

  In the above optical connector, the condensing position may monotonously change in the first direction from the beam on one end side to the beam on the other end side in the direction orthogonal to the axis. Thereby, for example, when each end face of a plurality of single core fibers is inclined with respect to the optical axis in a state of being flush with each other, the position of the condensing point of each beam can be aligned with each end face position. it can. Therefore, for example, the reflected return light can be reduced by a simple method such as polishing each end face in a bundle with a plurality of single core fibers bundled together.

  In the above optical connector, the second optical system includes a plurality of lenses that are respectively arranged on the optical axes of the plurality of beams and collect the corresponding beams, and the principal points of the plurality of lenses in the first direction. The positions may be different from each other. Thereby, the condensing position of the several beam in a 1st direction can be varied easily.

  In the above optical connector, the distance between the optical axis of the beam incident on the lens and the optical axis of the lens may change from the beam on one end to the beam on the other end in the direction orthogonal to the axis. Since the optical axis of the beam can be deflected by shifting the optical axis of the beam incident on the lens from the optical axis of the lens, the optical axes of a plurality of beams can be easily aligned with respect to a plane perpendicular to the axis. Can be tilted. Further, the amount of deviation of the optical axis (that is, the distance between the optical axis of the beam incident on the lens and the optical axis of the lens) changes from the beam on one end to the beam on the other end in the direction orthogonal to the axis. Thus, a plurality of beams inclined from each other from the first optical system can be emitted so that their optical axes are parallel to each other. As a result, the lens can realize the function of making the optical axes of the plurality of beams parallel to each other while inclining and the function of making the condensing positions of the plurality of beams different from each other in the first direction. Can be reduced.

  In the above optical connector, the second optical system has an optical component that receives the plurality of beams emitted from the first optical system and emits the plurality of beams so that the optical axes are parallel to each other. The plurality of lenses receive the plurality of beams emitted from the optical component and collect the plurality of beams, respectively, and the distance between the optical axis of the beam incident on the lens and the optical axis of the lens is determined by the plurality of lenses. May be equal to each other. As described above, the second optical system has a function of making the optical axes of the plurality of beams parallel to each other and a function of making the condensing positions of the plurality of beams different in the first direction. And a lens). Even with such a configuration, the above-described second optical system can be suitably realized. In addition, since the optical axes of the plurality of beams incident on the lens are parallel to each other, the alignment (optical axis adjustment) of each lens is facilitated.

  In the above optical connector, the first optical system may include a GRIN lens, and the end surface of the GRIN lens facing the multicore fiber may be inclined with respect to a plane perpendicular to the axis. As described above, since the first optical system includes the GRIN lens, a plurality of beams from the multi-core fiber can be emitted so that the optical axes are inclined with respect to each other. Further, when the end surface of the GRIN lens is perpendicular to the optical axes of the plurality of beams, reflected return light is generated. Like the optical connector described above, the end surface of the GRIN lens is inclined with respect to a plane perpendicular to the axis (that is, a plane perpendicular to the optical axes of a plurality of beams), so that such reflected return light is reduced. Can be reduced.

[Details of the embodiment of the present invention]
Specific examples of the optical connector 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 intends that all the changes within the meaning and range equivalent to the claim are included. In the following description, the same reference numerals are given to the same elements in the description of the drawings, and redundant descriptions are omitted.

(First embodiment)
FIG. 1 is a diagram schematically showing a cross section of an optical device including an optical connector according to a first embodiment of the present invention. In the figure, an XYZ orthogonal coordinate system is shown. The optical device 50 </ b> A includes an optical connector 1 </ b> A, a multicore fiber 30, and a plurality of single core fibers 40. The optical connector 1A optically couples each core of the multicore fiber 30 and each core of the plurality of single core fibers 40 along the axis A1. The XYZ orthogonal coordinate system is set so that the Z direction coincides with the extending direction (first direction) of the axis A1.

  FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1 and shows an XY cross section of the multicore fiber 30. The multi-core fiber 30 includes a plurality of cores 31 that are two-dimensionally arranged in a plane perpendicular to the optical axis direction, and a common clad 32 that collectively surrounds the plurality of cores 31. In one example, the multi-core fiber 30 has seven cores 31, one of which is arranged on the central axis of the multi-core fiber 30 (hereinafter referred to as the center core), and the other six are equally spaced around the center (center distance). H1) (hereinafter referred to as peripheral core). Each core 31 has a refractive index higher than that of the clad 32 and propagates separate light. Note that the end of the multi-core fiber 30 is inserted into and held by a cylindrical ferrule 35. The end surfaces of the multi-core fiber 30 and the ferrule 35 in the Z direction are polished to be flush with each other and are flat, and are slightly inclined in the −X direction with respect to a plane perpendicular to the axis A1 (see FIG. 1). The inclination angle of the end surface with respect to the plane is, for example, 8 °.

  Refer to FIG. 1 again. The optical connector 1A includes a first optical system 10A and a second optical system 20A arranged along the Z direction. One end of the first optical system 10A in the Z direction is optically coupled to the end face of the multi-core fiber 30, and the other end is optically coupled to one end of the second optical system 20A. The first optical system 10 </ b> A receives a plurality of beams having optical axes parallel to each other emitted from the plurality of cores 31 (see FIG. 2) of the multicore fiber 30. In FIG. 1, among the plurality of beams respectively emitted from the plurality of cores 31, the beam L <b> 2 emitted from one central core 31, and the beams L <b> 1 and L <b> 3 emitted from two peripheral cores 31, respectively. It is shown. The optical axes L1a to L3a of the plurality of beams L1 to L3 incident on the first optical system 10A are parallel to each other and parallel to the axis A1. The first optical system 10A emits these beams L1 to L3 so that the emitted optical axes L1a to L3a are inclined with respect to each other (that is, different from parallel), whereby the distance between the optical axes L1a to L3a. Adjust. In the example shown in FIG. 1, the first optical system 10A tilts the optical axes L1a and L3a of the beams L1 and L3 with respect to the optical axis L2a of the beam L2 so that the beams L1 and L3 gradually approach the beam L2. As a result, the optical axes L1a to L3a extend to the other end of the first optical system 10A while intersecting each other at a single point Q while widening the interval.

  The first optical system 10 </ b> A of this embodiment includes a GRIN lens 11 and a glass block 12. The GRIN lens 11 has a refractive index distribution (for example, a distribution in which the refractive index gradually decreases from the center toward the outer periphery) in a plane perpendicular to the axis A1, and is multi-core along the axis A1. Optically coupled to the fiber 30. In one example, the one end surface 11a of the GRIN lens 11 in the Z direction is polished flat and slightly inclined in the + X direction with respect to a plane perpendicular to the axis A1, and joined to the end surfaces of the multicore fiber 30 and the ferrule 35. Has been. The inclination angle of the end surface 11a with respect to the plane is, for example, 8 °. Further, the other end surface 11b of the GRIN lens 11 in the direction Z is flatly polished and is perpendicular to the axis A1.

  The beams L1 to L3 emitted from the multicore fiber 30 enter the GRIN lens 11 from the one end surface 11a. At the time of incidence, the beams L1 to L3 each have a constant radiation angle, but these beams L1 to L3 are collimated (collimated) by the lens action of the GRIN lens 11 and emitted from the other end surface 11b. Note that the distance between the one end surface 11a and the other end surface 11b of the GRIN lens 11 is defined so that the beams L1 to L3 are emitted from the other end surface 11b of the GRIN lens 11 in a state where the beams L1 to L3 are collimated in this way. Further, the beams L1 and L3 are deflected because the optical axes L1a and L3a at the time of incidence are away from the lens center of the GRIN lens 11, and the above-described inclination with respect to the optical axis L2a is given.

  The glass block 12 has a constant refractive index (for example, about 1.5) and has a cylindrical shape with the axis A1 as the central axis. The glass block 12 is optically coupled to the GRIN lens 11 along the axis A1 so that the lens center of the GRIN lens 11 and the center axis of the glass block 12 coincide with each other. In one example, the one end surface 12a and the other end surface 12b of the glass block 12 in the Z direction are polished flat and are perpendicular to the axis A1. The one end surface 12 a is joined to the other end surface 11 b of the GRIN lens 11. The beams L1 to L3 incident on the one end surface 12a propagate through the glass block 12 while maintaining the optical axes L1a to L3a inclined to each other, and are emitted from the other end surface 12b. The intervals between the optical axes L1a to L3a when emitted are adjusted by the propagation length of the beams L1 to L3 in the glass block 12 (that is, the optical distance between the one end surface 12a and the other end surface 12b). In this embodiment, since the space | interval of the cores of the several single core fiber 40 is larger than the space | interval of the cores 31 of the multi-core fiber 30 so that it may mention later, the glass block 12 so that the space | interval of the optical axes L1a-L3a may be expanded. The length of is secured.

  The second optical system 20A receives beams L1 to L3 emitted from the first optical system 10A at one end in the Z direction. The other end of the second optical system 20A in the Z direction is optically coupled to a plurality of single core fibers 40. The second optical system 20A emits beams L1 to L3 toward the respective cores of the plurality of single core fibers 40 so that the optical axes L1a to L3a are parallel to each other, and collects the beams L1 to L3. . At this time, the second optical system 20A slightly tilts the optical axes L1a to L3a of the beams L1 to L3 with respect to the axis A1. As a result, the optical axes L1a to L3a are inclined with respect to a plane perpendicular to the axis A1. Further, the second optical system 20A focuses the beams L1 to L3 at different positions in the Z direction (in other words, positions where the Z coordinates are different from each other).

  The second optical system 20 </ b> A of the present embodiment has a lens array 23. The lens array 23 includes a plurality of lenses 22 having the same number as the plurality of beams L1 to L3, and a main body (base) 21 that integrally holds the plurality of lenses 22, and the glass block 12 and the optical system along the axis A1. Combined. In one example, one end surface 21 a of the main body 21 in the Z direction is flatly polished, is perpendicular to the axis A <b> 1, and is joined to the other end surface 12 b of the glass block 12. Further, the other end surface 21b of the main body portion 21 in the direction Z is slightly inclined in the −X direction with respect to a plane perpendicular to the axis A1, and faces the end surfaces of the plurality of single core fibers 40 across a space. Yes. The inclination angle of the other end surface 21b with respect to the plane is, for example, 8 °.

  FIG. 3 is a front view of the lens array 23 as viewed from the Z direction (single core fiber 40 side). FIG. 4 is a diagram schematically illustrating a cross section taken along line IV-IV in FIG. 3. Note that the broken line in FIG. 4 represents a virtual outline used for designing the lens 22, but in reality, the lens 22 is integrated with the main body 21, and there is no boundary in the virtual line. .

  The plurality of lenses 22 are formed integrally with the other end surface 21b of the main body 21, and are disposed on the optical axes of the plurality of beams passing through the other end surface 21b, and overlap each other. In one example, as shown in FIG. 3, six lenses 22 are arranged around the central lens 22. The central lens 22 corresponds to one beam emitted from the central core 31 of the multicore fiber 30. The six surrounding lenses 22 correspond to the six beams emitted from the six peripheral cores 31 of the multicore fiber 30. The optical axis interval of each lens 22 is equal to the center interval between the cores of the plurality of single core fibers 40. As shown in FIG. 4, the lenses 22 are convex lenses, and their optical axis A2 is parallel to the axis A1. The plurality of lenses 22 condense the beams incident on each of them and emit them toward the single core fiber 40.

  Further, as shown in FIG. 4, the positions of the principal points 22a of the plurality of lenses 22 in the Z direction (that is, the Z coordinates of the principal points 22a) are different from each other. The position of the principal point 22a monotonously changes in the Z direction over the lens 22 on the side. This is because the other end surface 21b of the main body 21 is inclined with respect to a plane perpendicular to the axis A1, and the heights h1 from the other end surfaces 21b of the lenses 22 are equal to each other.

  FIG. 5 is a perspective view showing a plurality of single core fibers 40. 6 is a cross-sectional view showing a VI-VI cross section (XY cross section) shown in FIG. The number of single-core fibers 40 is equal to the number of cores 31 of the multi-core fiber 30, and is seven in one example. As shown in FIG. 6, the plurality of single core fibers 40 each have one core 41 and a clad 42 surrounding the core 41. Each core 41 has a higher refractive index than the clad 42. Each end of the plurality of single core fibers 40 is inserted and held in a plurality of cylindrical ferrules 46, respectively. Further, the plurality of ferrules 46 are bundled and integrated, and are accommodated and held in a cylindrical ring material 47 (see FIG. 5). In such a state, the optical axes of the cores 41 of the plurality of single core fibers 40 are parallel to each other and parallel to the axis A1 (see FIG. 1). The center interval H2 between the optical axes of the cores 41 (equal to the diameter of the ferrule 46) is larger than the center interval H1 between the optical axes of the cores 31 of the multicore fiber 30 (see FIG. 2). The end face 40a of each single core fiber 40 in the Z direction, the end face 46a of the ferrule 46, and the end face 47a of the ring material 47 are flattened by being polished together so as to be flush with each other, It is slightly inclined in the X direction with respect to a plane perpendicular to the axis A1. The inclination angles of the end faces 40a, 46a, and 47a with respect to the plane are, for example, 8 °.

  Here, FIG. 7 is an enlarged view showing a mode of optical coupling between the plurality of single core fibers 40 and the lens array 23. As shown in FIG. 5, the end faces 40a of the plurality of single core fibers 40 are flush with each other and inclined in the X direction with respect to a plane perpendicular to the axis A1. Accordingly, the position in the Z direction of each end face 40a of the single core fibers 40 arranged in the X direction is monotonously shifted by a certain amount. Therefore, in the present embodiment, the positions of the principal points 22a of the plurality of lenses 22 in the Z direction are set to be different from each other according to the Z direction position of the end face 40a of each single core fiber 40 (see FIG. 4). . Thereby, the condensing position of each beam can be matched with the position of the end surface 40a of each single core fiber 40 in the Z direction. That is, the distance between each lens 22 and the end face 40a of each single core fiber 40 is equal to the focal length of each lens 22, and the condensing position of each beam coincides with the end face 40a of each single core fiber 40. In one example, the condensing position monotonously changes in the Z direction from the beam L3 on one end side in the X direction to the beam L1 on the other end side.

  In the present embodiment, in order to deflect each beam, the optical axis of the beam incident on the lens 22 and the optical axis of the lens 22 are shifted from each other in at least one lens 22. The amount of deviation, that is, the distances W1 to W3 between the optical axes L1a to L3a of the beams L1 to L3 incident on the lens 22 and the optical axis A2 of each lens 22, are beams on the other end side from the beam L1 on one end side in the X direction. It has changed over L3.

  In one example, the interval W1 between the optical axis L1a of the beam L1 on one end side in the X direction and the optical axis A2 of the corresponding lens 22 is substantially zero. Accordingly, the beam L1 which is inclined in the + X direction and is incident on the lens 22 is emitted from the lens 22 while maintaining the inclination angle of the optical axis L1a without being deflected. On the other hand, the interval W2 between the optical axis L2a of the beam L2 located at the center in the X direction and the optical axis A2 of the corresponding lens 22 is larger than the interval W1. Accordingly, the beam L2 that has entered the lens 22 without being inclined in the X direction (that is, along the Z direction) is deflected in the + X direction by an angle corresponding to the interval W2, and the lens has an optical axis parallel to the beam L1. 22 is emitted. Further, the interval W3 between the optical axis L3a of the beam L3 located on the other end side in the X direction and the optical axis A2 of the corresponding lens 22 is further larger than the interval W2. Accordingly, the beam L3 which is inclined in the −X direction and is incident on the lens 22 is largely deflected in the + X direction by an angle corresponding to the interval W3 and is emitted from the lens 22 with an optical axis parallel to the beams L1 and L2. . As described above, the distance between the optical axis of the lens 22 and the optical axis of the beam is set to be larger as the angle between the parallel optical axis when emitted from the lens 22 and the optical axis when incident is larger.

  The effects obtained by the optical connector 1A of the present embodiment described above will be described. In the optical connector 1A of the present embodiment, the second optical system 20A condenses each of the plurality of beams L1 to L3 at different positions in the Z direction. Thereby, even if the positions of the end faces 40a of the plurality of single core fibers 40 in the optical axis direction are shifted from each other, the positions of the condensing points of the beams L1 to L3 can be easily set with respect to these positions. Can be matched. Accordingly, it is possible to easily avoid defocusing between the second optical system 20A and the plurality of single core fibers 40, and thus it is possible to suppress an increase in coupling loss. In the optical connector 1A, the optical axes L1a to L3a of the plurality of beams L1 to L3 emitted from the second optical system 20A are inclined with respect to the plane perpendicular to the axis A1. As a result, each of the beams L1 to L3 can be incident on the end face 40a of each single core fiber 40 at an appropriate angle, so that each beam L1 to L3 is incident on each end face 40a while reducing connection loss. The reflected light can be effectively reduced by increasing the angle.

  Further, as in the present embodiment, the condensing position may change monotonously in the Z direction from the beam L1 on one end side to the beam L3 on the other end side in the X direction. Thereby, for example, when the end faces 40a of the plurality of single core fibers 40 are inclined with respect to the optical axis in a state of being flush with each other, the condensing points of the beams L1 to L3 with respect to the respective end face positions. The position can be adjusted. Accordingly, for example, the reflected return light can be reduced by a simple method such as polishing each end face 40a in a lump in a state where a plurality of single core fibers 40 are bundled.

  In addition, as in the present embodiment, the second optical system 20A includes a plurality of lenses 22 that are respectively disposed on the optical axes L1a to L3a and collect the corresponding beams L1 to L3, and a plurality of lenses 22 in the Z direction. The positions of the principal points 22a of the lenses 22 may be different from each other. Thereby, the condensing position of the some beam L1-L3 in a Z direction can be varied easily.

  Further, as in the present embodiment, intervals W1 to W3 between the optical axes L1a to L3a of the beams L1 to L3 incident on the lens 22 and the optical axis A2 of the lens 22 are different from the beam L1 on one end side in the X direction. It may change over the beam L3 on the end side. Since the optical axes L1a to L3a can be deflected by shifting the optical axes L1a to L3a of the beams L1 to L3 incident on the lens 22 from the optical axis A2 of the lens 22, the optical axes L1a to L3a are axial lines. It can be easily inclined with respect to a plane perpendicular to A1. Further, the shift amounts (that is, the intervals W1 to W3) of the optical axes L1a to L3a are changed from the beam L1 on one end side to the beam L3 on the other end side in the X direction. The inclined beams L1 to L3 can be emitted so that the optical axes L1a to L3a are parallel to each other. Accordingly, the lens 22 can realize the function of making the optical axes L1a to L3a in parallel while inclining the optical axes L1a to L3a and the function of making the condensing positions of the plurality of beams L1 to L3 different in the Z direction. The score can be reduced.

  Further, as in the present embodiment, the first optical system 10A includes the GRIN lens 11, and the end surface 11a of the GRIN lens 11 facing the multicore fiber 30 may be inclined with respect to a plane perpendicular to the axis A1. . As described above, since the first optical system 10A includes the GRIN lens 11, a plurality of beams L1 to L3 from the multicore fiber 30 can be emitted so that the optical axes L1a to L3a are inclined with respect to each other. When the end surface 11a of the GRIN lens 11 is perpendicular to the optical axes L1a to L3a before incidence, reflected return light to the multicore fiber 30 is generated. As in the present embodiment, the end surface 11a of the GRIN lens 11 is inclined with respect to a surface perpendicular to the axis A1 (that is, a surface perpendicular to the optical axes L1a to L3a before incidence). The reflected return light can be reduced.

(Second Embodiment)
FIG. 8 is a diagram schematically showing a cross section of an optical device including an optical connector according to the second embodiment of the present invention. The optical device 50B includes an optical connector 1B, a multi-core fiber 30, and a plurality of single core fibers 40. The optical connector 1B optically couples each core of the multicore fiber 30 and each core of the plurality of single core fibers 40 along the axis A1. The configurations of the multi-core fiber 30 and the plurality of single-core fibers 40 are the same as those in the first embodiment described above except that the end surface of the multi-core fiber 30 is perpendicular (not inclined) to the axis A1. is there.

  The optical connector 1B includes a first optical system 10B and a second optical system 20B arranged along the Z direction. The first optical system 10B is disposed on the optical axis between the multi-core fiber 30 and the second optical system 20B, and is optically coupled to these. The first optical system 10B has the same function as the first optical system 10A of the first embodiment, and its configuration is different from the first optical system 10A. That is, the first optical system 10 </ b> B of the present embodiment is configured by a convex lens such as a collimating lens 13. The collimating lens 13 is disposed at a position away from the end face of the multi-core fiber 30 by the focal length f. Beams L <b> 1 to L <b> 3 emitted from the multicore fiber 30 enter the collimating lens 13. Although the beams L1 to L3 have a certain spread at the time of incidence, the beams L1 to L3 are collimated by the collimating lens 13 and emitted. The optical axes L1a to L3a of the beams L1 to L3 are parallel to each other at the time of incidence on the collimating lens 13, but are deflected because the optical axes L1a and L3a are away from the lens center of the collimating lens 13. Thereby, the same inclination as that of the first embodiment is given to the beams L1 and L3 so that the beams L1 to L3 intersect each other at a position away from the collimating lens 13 by the focal length f. As in the first embodiment, the distance between the optical axes L1a to L3a is adjusted by arbitrarily setting the distance between the collimating lens 13 and the second optical system 20B.

  The second optical system 20B includes a lens array 23 and a prism 24. The configuration of the lens array 23 is the same as in the first embodiment. The prism 24 is an optical component that receives the plurality of beams L1 to L3 emitted from the first optical system 10B and emits the plurality of beams L1 to L3 so that the optical axes L1a to L3a are parallel to each other. The prism 24 has a light incident surface 24 a optically coupled to the collimating lens 13 and a light emitting surface 24 b optically coupled to one end surface 21 a of the lens array 23. The light incident surface 24a is flat and perpendicular to the axis A1. The light emission surface 24b includes a plurality of surfaces 24b1 to 24b3 respectively corresponding to the plurality of beams L1 to L3. The surface 24b2 is perpendicular to the axis A1, and the optical axis L2a of the beam L2 incident on the prism 24 without being inclined in the X direction (that is, along the Z direction) is not refracted when passing through the surface 24b2. , And emitted along the axis A1. On the other hand, the surface 24b1 is inclined in the + X direction with respect to the surface perpendicular to the axis A1, and the optical axis L1a of the beam L1 which is inclined in the + X direction and enters the prism 24 is −X when passing through the surface 24b1. Refracted in the direction and emitted with an optical axis parallel to the beam L2. Further, the surface 24b3 is inclined in the −X direction with respect to the surface perpendicular to the axis A1, and the optical axis L3a of the beam L3 incident on the prism 24 after being inclined in the −X direction passes through the surface 24b3. The light is refracted in the + X direction and emitted with an optical axis parallel to the beam L2. Thus, the prism 24 has the surfaces 24b1 to 24b3 inclined corresponding to the inclinations of the beams L1 to L3, so that the optical axes L1a to L3a of the beams L1 to L3 are parallel to each other.

  Therefore, unlike the first embodiment, beams L1 to L3 having optical axes L1a to L3a parallel to each other are incident on one end surface 21a of the lens array 23. For this reason, in the lens array 23 of this embodiment, the function which makes the optical axes L1a-L3a mutually parallel is unnecessary. That is, in the present embodiment, the intervals between the optical axes L1a to L3a of the beams L1 to L3 incident on the lens 22 and the optical axis A2 of each lens 22 are equal to each other in the plurality of lenses 22. However, this interval is not zero and has a significant value. For this reason, the optical axes L1a to L3a of the beams L1 to L3 emitted from the lenses 22 are slightly inclined with respect to the axis A1. As a result, the optical axes L1a to L3a are inclined with respect to a plane perpendicular to the axis A1. As in the first embodiment, the lens array 23 focuses the beams L1 to L3 at different positions in the Z direction (in other words, positions where the Z coordinates are different from each other).

  According to the optical connector 1B of the present embodiment, the same effects as those of the first embodiment can be obtained. In the present embodiment, the second optical system 20B has a function of making the optical axes L1a to L3a parallel to each other and a function of making the condensing positions of the beams L1 to L3 in the Z direction different from each other. This is realized by (the prism 24 and the lens array 23). Even with such a configuration, the second optical system 20B can be suitably realized. Further, since the optical axes L1a to L3a of the beams L1 to L3 incident on the lens array 23 are parallel to each other, the alignment (optical axis adjustment) of each lens 22 is facilitated.

  Note that, as in the present embodiment, the end face of the multi-core fiber 30 may not be inclined with respect to a plane perpendicular to the axis A1. The same applies to the first embodiment. Also in this embodiment, the GRIN lens 11 shown in FIG. 1 may be used as the first optical system instead of the collimating lens 13.

  The optical connector according to the present invention is not limited to the above-described embodiment, and various other modifications are possible. For example, in each of the above embodiments, the case where the Z-direction positions of the end faces of a plurality of single-core fibers are monotonously changing in the X-direction is exemplified, but the Z-direction positions of the end faces of the plurality of single-core fibers are changed in a complicated manner. Even in such a case, the condensing position of each beam can be adjusted to each end face by the second optical system.

  DESCRIPTION OF SYMBOLS 1A, 1B ... Optical connector, 10A, 10B ... 1st optical system, 11 ... GRIN lens, 12 ... Glass block, 13 ... Collimate lens, 20A, 20B ... 2nd optical system, 21 ... Main-body part, 22 ... Lens, 22a ... principal point, 23 ... lens array, 24 ... prism, 24a ... light incident surface, 24b ... light exit surface, 30 ... multi-core fiber, 31 ... core, 32 ... clad, 35 ... ferrule, 40 ... single core fiber, 41 ... Core, 42 ... clad, 46 ... ferrule, 47 ... ring material, 50A, 50B ... optical device, A1 ... axis, A2 ... optical axis, L1 ... beam, L1-L3 ... beam, L1a-L3a ... optical axis.

Claims (6)

Each core of a multi-core fiber having a plurality of cores and a common clad surrounding the plurality of cores, and each core of a plurality of single-core fibers each having a single core and a clad surrounding the core are arranged along a certain axis. An optical connector that optically couples along
A first optical system that receives a plurality of beams having optical axes parallel to each other and emitted from the plurality of cores of the multi-core fiber, and emits the plurality of beams so that the optical axes are inclined with respect to each other;
Second optics that receives the plurality of beams emitted from the first optical system and emits the plurality of beams toward the plurality of cores of the plurality of single core fibers so that optical axes thereof are parallel to each other. The system,
With
The optical axes of the plurality of beams incident on the first optical system are parallel to the axis,
The first optical system has a common lens for the plurality of beams, and the plurality of beams incident on the first optical system increase the distance from each other after their optical axes intersect at one point. Emitted from the first optical system,
The optical axes of the plurality of beams emitted from the second optical system are inclined with respect to a plane perpendicular to the axis,
The second optical system is an optical connector that condenses the plurality of beams at positions different from each other in a first direction that is an extending direction of the axis.   2. The optical connector according to claim 1, wherein a converging position monotonously changes in the first direction from the beam on one end side to the beam on the other end side in a direction orthogonal to the axis. The second optical system includes a plurality of lenses that are respectively arranged on optical axes of the plurality of beams and collect the corresponding beams.
The optical connector according to claim 1, wherein positions of principal points of the plurality of lenses in the first direction are different from each other. The distance between the optical axis of the beam incident on each of the plurality of lenses and the optical axis of each lens varies from the beam on one end side to the beam on the other end side in a direction orthogonal to the axis. Item 4. The optical connector according to Item 3. The second optical system includes an optical component that receives the plurality of beams emitted from the first optical system and emits the plurality of beams so that optical axes are parallel to each other.
The plurality of lenses receive the plurality of beams emitted from the optical component and collect the plurality of beams, respectively.
The optical connector according to claim 3, wherein an interval between an optical axis of the beam incident on each of the plurality of lenses and an optical axis of each lens is equal to each other in the plurality of lenses. It said common lens is a GRIN lens,
6. The optical connector according to claim 1, wherein an end face of the GRIN lens facing the multi-core fiber is inclined with respect to a plane perpendicular to the axis.

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