JP2016184104A - Ferrule with optical fiber and optical connector system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ferrule with an optical fiber preventing optical loss, without providing the ferrule with a lens, and an optical connector system.SOLUTION: A ferrule with an optical fiber includes: a ferrule 10 having a plurality of fiber holes 15; a lensed fiber 1 in which a tip of an optical fiber 2 is fusion-spliced to a GRIN lens 3; and a flat plate 30 that can transmit light propagating in the optical fiber 2, that is mounted on an end surface of the ferrule 10, and against which an end surface of the lensed fiber 1 inserted into the fiber hole 15 is butted. The end surface 11 of the ferrule 10 and the flat plate 30 are inclined with respect to a surface vertical to an optical axis of the lensed fiber 1 inserted into the fiber hole 15. A gap between the end surface of the lensed fiber 1 and the flat plate 30 is filled with a refractive index matching agent.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a ferrule with an optical fiber and an optical connector system.

  A ferrule defined in JIS C 5981 (F12 type multi-core optical fiber connector: MT connector) is known as a pin fitting positioning type resin ferrule having guide pin holes on both sides of a plurality of optical fiber holes arranged side by side. ing. In this type of ferrule, the connection end faces of the opposed ferrules are brought into contact with each other, whereby the end face of the optical fiber at the connection end face is physically connected (Physical Contact). In JIS C 5982 (F13 type multi-core optical fiber connector: MPO connector), the connection end face of the ferrule is polished obliquely. For example, also in FIG. 6 of Patent Document 1, the connection end face of the ferrule is obliquely polished. When the connection end face of the ferrule is obliquely polished, the end face of the optical fiber is also obliquely polished, and the return loss characteristics are improved.

  In Patent Document 2, it is described that an axial deviation of the optical fiber occurs when the connection end surfaces polished obliquely are brought into contact with each other. In order to suppress an increase in optical loss due to such an optical axis shift of the optical fiber, Patent Document 3 describes that a collimator lens is formed on the ferrule.

JP 2002-006177 A JP 2005-181832 A JP 2011-059486 A

  Since the ferrule described in Patent Document 3 requires a lens, resin molding is difficult and manufacturing costs are increased. On the other hand, when the MFD (Mode Field Diameter) is small without forming a lens on the ferrule, if the optical fiber is misaligned, the optical loss increases and the optical loss due to dust adhering to the end face of the optical fiber also occurs. Cheap.

  An object of this invention is to suppress optical loss, without providing a lens in a ferrule.

  A main invention for achieving the above object includes a ferrule having a plurality of fiber holes, a lensed fiber in which a GRIN lens is fused and connected to the tip of an optical fiber, and a flat plate capable of transmitting light propagating through the optical fiber. A flat plate attached to an end face of the ferrule and against which an end face of the lensed fiber inserted into the fiber hole is abutted, and the end face and the flat plate of the ferrule have the fiber hole Inclined with respect to a plane perpendicular to the optical axis of the lensed fiber inserted into the lens, and a gap between the end surface of the lensed fiber and the flat plate is filled with a refractive index matching agent. It is a ferrule with a fiber.

  Other characteristics of the present invention will be made clear by the description and drawings described later.

  According to the present invention, light loss can be suppressed without providing a lens on the ferrule.

FIG. 1 is an explanatory diagram of the lensed fiber 1 and the end face 11 of the ferrule 10. FIG. 2 is an explanatory diagram of the ferrule 10. FIG. 3A to FIG. 3C are explanatory diagrams of a state at the time of optical connection. FIG. 3A is an explanatory diagram of the optical connector system 20 in which the optical connector 21 having the ferrule 10 with an optical fiber is inserted from both sides of the adapter 22. 3B and 3C are explanatory diagrams of the positional relationship of the ferrule 10 in the adapter 22. FIG. 4 is a flowchart of a method for manufacturing the ferrule 10 with an optical fiber. FIG. 5A is a perspective view of the ferrule 10 of the second embodiment. FIG. 5B is an explanatory diagram of a state when the adhesive (refractive index matching agent) is filled in the second embodiment. FIG. 6 is a perspective view of a ferrule 10 of a modified example of the second embodiment. FIG. 7 is an explanatory diagram of a ferrule 10 according to a modification of the second embodiment. FIG. 8A is a perspective view of the ferrule 10 of the third embodiment. FIG. 8B is an explanatory diagram of a state when the adhesive (refractive index matching agent) is filled in the third embodiment. FIG. 9 is an explanatory diagram of a ferrule 10 according to a modification of the third embodiment. FIG. 10A is an explanatory diagram of a state when an adhesive (refractive index matching agent) is filled in a modified example of the third embodiment. FIG. 10B is an explanatory diagram at the time of optical connection in the optical connector system having the ferrule 10 of a modification of the third embodiment. FIG. 11 is a flowchart of the manufacturing method of the ferrule 10 with an optical fiber of the fourth embodiment. FIG. 12 is an explanatory diagram of the relationship between the hardness and thickness of the solid refractive index matching material sheet. FIG. 13A is an explanatory diagram of the ferrule 10 of the fifth embodiment. FIG. 13B is an explanatory diagram of a state when the ferrule 10 of the fifth embodiment is optically connected. FIG. 14A is an explanatory diagram of the ferrule 10 of the sixth embodiment.

  At least the following matters will be apparent from the description and drawings described below.

  A ferrule having a plurality of fiber holes; a lensed fiber in which a GRIN lens is fused and connected to the tip of the optical fiber; and a flat plate capable of transmitting light propagating through the optical fiber, and is attached to an end face of the ferrule. A flat plate against which an end face of the lensed fiber inserted into the fiber hole is abutted, and the end face of the ferrule and the flat plate are optical axes of the lensed fiber inserted into the fiber hole. The ferrule with a fiber is characterized in that it is inclined with respect to a plane perpendicular to the surface and a refractive index matching agent is filled in a gap between the end face of the lensed fiber and the flat plate. According to such a ferrule with a fiber, light loss can be suppressed without providing a lens on the ferrule.

  It is desirable that an antireflection film is formed on the outer surface of the flat plate. Thereby, the return loss can be suppressed.

  The ferrule is preferably formed with a recess recessed from the end face of the ferrule, and the space surrounded by the flat plate and the recess is filled with the refractive index matching agent. This facilitates filling of the refractive index matching agent.

  It is desirable that a fiber groove for supporting the lensed fiber is formed on the bottom surface of the recess. This makes it difficult for the end of the lensed fiber to bend.

  The recess is formed with a fiber hole opening surface facing the inner surface of the flat plate, and a plurality of the fiber holes are opened, projecting from the fiber hole opening surface to the flat plate side, It is desirable to form a protrusion that contacts the edge. Thereby, distortion of a flat plate can be suppressed.

  A groove is formed on the end face of the ferrule so as to penetrate through the upper part of the openings of the plurality of fiber holes, and at least a part of the inner wall surface constituting the groove is above the fiber hole. It is desirable to be located at. This makes it difficult for bubbles to be formed on the end face of the lensed fiber.

  It is desirable that a solid refractive index matching material whose surface is deformed when the end surface of the lensed fiber is abutted is disposed on the inner surface of the flat plate. This makes it difficult for bubbles to be formed on the end face of the lensed fiber.

  It is desirable that both surfaces of the solid refractive index matching material have adhesiveness. This makes it difficult for the solid refractive index matching material to peel from the end surfaces of the flat plate and the lensed fiber.

  The shore A hardness and thickness of the solid refractive index matching material are as follows: Shore A hardness is 0, thickness is 30 μm, Shore A hardness is 70, thickness is 30 μm, Shore A hardness is 70, thickness is It is desirable to be within a range surrounded by four points of a 50 μm point, a Shore A hardness of 0, and a thickness of 150 μm. Thereby, it becomes difficult for bubbles to be formed on the end face of the lensed fiber abutted against the solid refractive index matching material.

  An optical connector system having an adapter and two optical connectors inserted on both sides of the adapter, each optical connector having a ferrule having a plurality of fiber holes and a GRIN lens fused to the tip of the optical fiber. A lensed fiber that is fixedly connected and a flat plate that can transmit light propagating through the optical fiber, and is attached to an end surface of the ferrule and abuts the end surface of the lensed fiber that is inserted into the fiber hole. The end face of the ferrule and the flat plate are inclined with respect to a plane perpendicular to the optical axis of the lensed fiber inserted into the fiber hole, and the end face of the lensed fiber A refractive index matching agent is filled in a gap between the flat plate and the flat plate, and the adapter has a spacer protruding inward. By the ferrule is in contact with the spacer in part, the optical connector system, wherein the end faces of the ferrules are disposed opposite at a predetermined interval becomes apparent. According to such an optical connector system, light loss can be suppressed without providing a lens on the ferrule.

=== First Embodiment ===
<End faces of lensed fiber 1 and ferrule 10>
FIG. 1 is an explanatory diagram of the lensed fiber 1 and the end face 11 of the ferrule 10. Note that the dimensions and angles are exaggerated for easy understanding.

  The lensed fiber 1 is an optical fiber that includes a single mode optical fiber 2 and a GRIN lens 3, and the GRIN lens 3 is fused and connected to the tip of the single mode optical fiber 2.

  The GRIN lens 3 is a gradient index lens whose refractive index gradually decreases from the central axis toward the outer periphery. Since the refractive index of the graded index optical fiber gradually decreases from the central axis toward the outer periphery, a graded index optical fiber can be used as the GRIN lens 3. The GRIN lens 3 has a predetermined length so as to function as a collimator lens. Specifically, the GRIN lens 3 has a length (2n + 1) / 4 times the length of the standing wave for one cycle (where n is an integer equal to or greater than 0), Then, the length of the GRIN lens 3 is, for example, 590 μm. As a result, light incident on the GRIN lens 3 from the single mode optical fiber 2 is converted into parallel light in the GRIN lens 3 and emitted from the GRIN lens 3. On the contrary, the parallel light incident on the GRIN lens 3 is converged in the GRIN lens 3 and is incident on the single mode optical fiber 2 from the GRIN lens 3.

  A flat plate 30 capable of transmitting an optical signal is arranged at the tip of the GRIN lens. The flat plate 30 is disposed so as to be inclined with respect to a plane perpendicular to the optical axis of the lensed fiber 1 with the end face of the lensed fiber 1 being abutted against it. Here, the flat plate 30 is inclined by 8 degrees with respect to a plane perpendicular to the optical axis. Since the end surface 11 of the ferrule 10 is inclined with respect to a surface perpendicular to the optical axis of the lensed fiber 1, the flat plate 30 is disposed on the end surface 11 of the ferrule 10, so that the flat plate 30 becomes the optical axis of the lensed fiber 1. It is arranged to be inclined with respect to a plane perpendicular to. By inclining the end face of the flat plate 30, the return loss can be reduced. If the end surface of the GRIN lens 3 is tilted, the length of the GRIN lens 3 is changed, so that the function as a collimator lens is impaired.

  A refractive index matching agent is filled between the flat plate 30 and the end face of the lensed fiber 1. This is because the end surface of the lensed fiber 1 is perpendicular to the optical axis, and the flat plate 30 is inclined with respect to the surface perpendicular to the optical axis, so that there is a gap between the end surface of the lensed fiber 1 and the flat plate 30. This is because it occurs. The refractive index of the refractive index matching agent is adjusted to the same degree as the refractive index of the lensed fiber 1 or the flat plate 30 (the refractive index of glass). In other words, the refractive index of the refractive index matching agent is adjusted to be closer to the refractive index of the lensed fiber 10 or the flat plate 30 than the refractive index of air. For this reason, Fresnel reflection can be suppressed by filling the refractive index matching agent.

  Next, the path of the optical signal propagating through the two lensed fibers 1 will be described. Here, it is assumed that the optical signal propagates from the left lensed fiber 1 to the right lensed fiber 1.

  The optical signal propagated through the left lensed fiber 1 is emitted from the inclined surface outside the flat plate 30 toward the right side through the refractive index matching agent and the flat plate 30. Since the outside of the inclined surface of the flat plate 30 is air, the optical signal is refracted according to Snell's law (the refractive index of the flat plate 30 is, for example, 1.46). As a result, the optical signal emitted from the left flat plate 30 is refracted upward on the opposite side of the inclined surface of the flat plate 30 (downward) (here, refracted upward by about 3.9 degrees).

  An optical signal (parallel light) that has been inclined upward with respect to the optical axis and propagated through the air enters the inclined surface of the right flat plate 30. The inclined plane of the right flat plate 30 is inclined by 8 degrees with respect to the plane perpendicular to the optical axis of the lensed fiber 1, and is arranged in parallel with the left flat plate 30. As a result, the optical signal incident on the inclined surface of the right flat plate 30 is refracted and then propagates through the lensed fiber 1 via the flat plate 30 and the refractive index matching agent.

  In order to optically connect the left and right lensed fibers 1, it is necessary to displace the optical axes of the lensed fibers 1 in anticipation that the refracted optical signal propagates in the air. Specifically, when the distance between the end faces of the GRIN lens 3 is 900 μm, the amount G of deviation of the optical axis of the lensed fiber 1 is about 30 μm. The deviation amount (= G / 2: offset amount) between the positioning portion (positioning hole 13 or positioning pin 14) of the ferrule 10 and the fiber hole 15 is about 15 μm. In the following description, the interval between the end surfaces 11 of the ferrule 10 for optically connecting the left and right lensed fibers 1 (interval in the optical axis direction of the lensed fiber 1) is L.

  In this embodiment, since it is not necessary to form a lens on the ferrule 10, the manufacture of the ferrule 10 is easy. Further, since the MFD (Mode Field Diameter) of the optical signal propagating between the ferrules 10 is large, the optical loss can be suppressed even if the optical axis shift of the lensed fiber 1 is somewhat caused, and it is attached to the end face of the lensed fiber 1 Light loss due to dust can also be suppressed. Further, the end faces 11 of the ferrule 10 need not be brought into contact with each other, and the end faces of the lensed fiber 1 are not in direct contact with each other. There is also an advantage that the end face of 1 is hardly damaged. Further, since the inclined surfaces of the flat plate 30 are not in direct contact with each other, there is an advantage that the coating on the inclined surface of the flat plate 30 subjected to the antireflection treatment is hardly damaged.

<About Ferrule 10>
FIG. 2 is an explanatory diagram of the ferrule 10. In the following description, the direction in which the two positioning holes 13 are arranged is referred to as “left-right direction”. In addition, the axial direction of the positioning hole 13 is “front-rear direction”, the side facing the counterpart ferrule 10 is “front”, and the opposite side is “rear”. Further, a direction perpendicular to the left-right direction and the front-rear direction is referred to as “up-down direction”, the side where the adhesive filling window 16 is provided is “upper”, and the opposite side is “lower”.

  The ferrule 10 is a member that holds the end of the lensed fiber 1. On the rear side of the ferrule 10, a flange 12 is formed. The collar portion 12 is a portion protruding outward from the outer peripheral surface. The ferrule 10 including the flange portion 12 is integrally formed of resin. The ends of the plurality of lensed fibers 1 are held inside the ferrule 10. The ferrule 10 of the present embodiment has substantially the same configuration as a ferrule having an inclined end surface defined by JIS C 5982 (F13 type multi-core optical fiber connector: MPO connector), and includes a positioning hole 13, a fiber hole 15, and the like. The dimensions and positional relationship are as defined in the standard. However, the position of the fiber hole 15 is shifted downward by an amount corresponding to G / 2 in FIG. 1 with respect to the positioning hole 13 when the end face 11 of the ferrule 10 is viewed from the front side.

  The ferrule 10 has two positioning holes 13, a plurality of fiber holes 15, and an adhesive filling window 16. In addition, the ferrule 10 has a flat plate 30 attached to the end surface 11.

  The positioning hole 13 is a hole for inserting the positioning pin 14 (see FIG. 3A). The positioning hole 13 and the positioning pin 14 serve as a positioning portion that positions the ferrule 10. The ferrules 10 are aligned with each other by inserting the positioning pins 14 into the positioning holes 13. The positioning holes 13 pass through the ferrule 10 in the front-rear direction, and are formed at intervals in the left-right direction so as to sandwich the plurality of fiber holes 15 from the left and right.

  The fiber hole 15 is a hole for inserting the end of the lensed fiber 1. The lensed fiber 1 is inserted into the fiber hole 15 as shown in FIG. The fiber hole 15 penetrates between the front end face 11 of the ferrule 10 and the adhesive filling window 16. The fiber holes 15 are formed in parallel in the front-rear direction, and the plurality of fiber holes 15 are arranged side by side in the left-right direction. Here, twelve fiber holes 15 are arranged in a line in the left-right direction. The fiber hole 15 is a part that forms an optical path inside the ferrule 10 and is a hole parallel to the optical axis of the lensed fiber 1.

  The adhesive filling window 16 is a cavity for filling the adhesive. A fiber insertion port (not shown) for inserting the lensed fiber 1 is formed on the rear end surface of the ferrule 10. The lensed fiber 1 inserted from the fiber insertion port has an adhesive filling window 16. It will be inserted into the fiber hole 15 across. By filling the adhesive from the adhesive filling window 16, the lensed fiber 1 is fixed to the ferrule 10.

  On the front end face 11 of the ferrule 10, a positioning hole 13 is opened and a plurality of fiber holes 15 are opened. A flat plate 30 is attached to the front end face 11 of the ferrule 10. Since the positioning hole 13 is not blocked by the flat plate 30, the positioning pin 14 can be inserted into the positioning hole 13 even after the flat plate 30 is attached. On the other hand, the opening of the fiber hole 15 is blocked by the flat plate 30.

  The front end face 11 of the ferrule 10 is inclined with respect to a plane perpendicular to the axial direction of the fiber hole 15. For this reason, the front end face 11 of the ferrule 10 is inclined with respect to a plane perpendicular to the optical axis of the lensed fiber 1 inserted into the fiber hole 15. Since the end face of the lensed fiber 1 is perpendicular to the optical axis, the front end face 11 of the ferrule 10 is inclined with respect to the end face of the lensed fiber 1 inserted into the fiber hole 15.

  The front end face 11 of the ferrule 10 is inclined with respect to the vertical direction when viewed from the left-right direction. More specifically, the front end surface 11 of the ferrule 10 is inclined by 8 degrees with respect to the vertical direction so that the upper side of the ferrule 10 (adhesive filling window 16 side) is the front side. That is, the front end face 11 of the ferrule 10 is inclined so as to face downward. By inclining the front end face 11 of the ferrule 10, it becomes easy to place the flat plate 30 so as to be inclined with respect to a plane perpendicular to the optical axis of the lensed fiber 1.

  Note that the center positions of the plurality of fiber holes 15 with respect to the positioning holes 13 with the end face 11 being inclined toward the ferrule on the other side toward the upper side (adhesive filling window 16 side). The position is shifted to the lower side (the side opposite to the adhesive filling window 16 side). That is, the center position (center of gravity position) of the plurality of fiber holes 15 is shifted downward by an amount corresponding to G / 2 in FIG. 1 when the end face 11 of the ferrule 10 is viewed from the front side. ing. Thereby, even if the optical signal is refracted on the inclined surface as shown in FIG. 1, the optical connection is possible.

  The flat plate 30 is, for example, a glass plate that can transmit light propagating through the optical fiber 2. The inner (rear) surface of the flat plate 30 faces the end surface of the lensed fiber 1, and the outer (front) surface of the flat plate 30 is connected to the flat plate 30 attached to the end surface 11 of the counterpart ferrule 10. opposite.

  The shape of the flat plate 30 is a plate shape that is long in the left-right direction. However, the shape of the flat plate 30 is not limited to this shape, and may be other shapes such as a trapezoidal shape and a rhombus shape when viewed from the front-rear direction. The horizontal dimension of the flat plate 30 is such a length that the positioning holes 13 are not blocked while closing the openings of the plurality of fiber holes 15 arranged in the left-right direction. That is, the edge in the left-right direction of the flat plate 30 is located between the fiber hole 15 located at the end and the positioning hole 13.

  The outer (front) surface of the flat plate 30 is coated with an antireflection film. For example, the antireflection film is an AR coating film in which two types of thin films having different refractive indexes are stacked. By forming an antireflection film on the flat plate, transmission loss and reflection attenuation can be reduced. Although the volume that can be processed at one time by the film forming apparatus is limited, since the object of the film forming process is a single flat plate 30, it is possible to set a large number of flat plates 30 in the film forming apparatus, and the cost is low. Thus, an antireflection film can be formed on the flat plate 30. Note that if the AR coating process is performed on the end face of the lensed fiber 1 or the AR coated process is performed on the lensed fiber 1 attached to the ferrule, the throughput of the film forming apparatus is reduced. The coating of the protective film is costly.

  FIG. 3A to FIG. 3C are explanatory diagrams of a state at the time of optical connection. FIG. 3A is an explanatory diagram of the optical connector system 20 in which the optical connector 21 having the ferrule 10 with an optical fiber is inserted from both sides of the adapter 22. 3B and 3C are explanatory diagrams of the positional relationship of the ferrule 10 in the adapter 22. The optical connector system 20 includes two optical connectors 21 each having the ferrule 10 with an optical fiber, and an adapter 22 into which the two optical connectors 21 can be inserted from both sides.

  As shown in FIG. 3A, when the optical connector 21 is inserted from both sides of the adapter 22, the end surfaces 11 of the ferrule 10 of the optical connector 21 are arranged to face each other, and the flat plates 30 attached to the end surface 11 Are arranged opposite to each other. Positioning pins 14 protrude from the ferrule 10 of the male optical connector 21, and the positioning pins 14 are inserted into the positioning holes 13 of the ferrule 10 of the female optical connector 21, thereby positioning the ferrules 10 within the adapter 22. Positioning is performed in a direction perpendicular to the pin 14 (left and right direction and up and down direction). It should be noted that the ferrule 10 is opposed so that the upper and lower directions of the ferrule 10 are reversed (the adhesive filling window 16 is reversed) so that the flat plates 30 are parallel to each other.

  A spacer 23 that protrudes inward is formed inside the adapter 22. The dimension in the front-rear direction of the spacer 23 corresponds to the distance L between the end faces 11 of the ferrule 10 described above. When the ferrule 10 comes into contact with the spacer 23, as shown in FIGS. 3B and 3C, the end faces 11 of the ferrule 10 are arranged to face each other at a predetermined interval L, and the flat plates 30 attached to the end face 11 are in contact with each other. Are arranged facing each other at a predetermined interval. That is, when the ferrule 10 contacts the spacer 23 in the adapter 22, the ferrules 10 are aligned in the front-rear direction and the flat plates 30 are aligned in the front-rear direction. Here, the front end face 11 (inclined end face) of the ferrule 10 is in contact with the spacer 23, but the end face 11 of the ferrule 10 is opposed at a predetermined interval L by the flange portion 12 of the ferrule 10 being in contact with the spacer 23. You may make it let it.

<Method for Manufacturing Ferrule 10 with Optical Fiber>
FIG. 4 is a flowchart of a method for manufacturing the ferrule 10 with an optical fiber.

  First, the lensed fiber 1 is created (S101). Specifically, first, a graded index optical fiber is fusion spliced to the single mode optical fiber 2, and the fused graded index optical fiber is cut to a predetermined length, and the tip of the single mode optical fiber 2 is cut. A GRIN lens 3 is formed. At this time, the end surface (cut surface) of the GRIN lens 3 is perpendicular to the optical axis of the lensed fiber 1. Note that the fusion splicing is performed so that the outer diameter of the fusion spliced portion can be inserted into the fiber hole 15 (the fiber hole 15 having the inner diameter defined by the standard). A plurality of such lensed fibers 1 are prepared.

  Next, an operator prepares the above-mentioned ferrule 10, and arrange | positions the flat plate 30 on the end surface 11 of the ferrule 10 (S102). Since the front end face 11 of the ferrule 10 is inclined, when the flat plate 30 is pressed against and contacted with the end face 11, the flat plate 30 is inclined with respect to a plane perpendicular to the axial direction of the fiber hole 15 of the ferrule 10. Be placed.

  Next, the operator bonds the lensed fiber 1 and the flat plate 30 to the ferrule 10 (S103). When the lensed fiber 1 and the flat plate 30 are bonded to the ferrule 10, the end face of the lensed fiber 1 is in contact with the flat plate 30. Since the end surface of the lensed fiber 1 is perpendicular to the optical axis and the flat plate 30 is inclined with respect to the surface perpendicular to the optical axis, there is a gap between the end surface of the lensed fiber 1 and the flat plate 30. This gap is filled with an adhesive serving as a refractive index matching agent. Since the gap between the end surface 11 of the ferrule 10 and the flat plate 30 is very small, the adhesive (refractive index matching) is applied by applying an adhesive to the boundary between the end surface 11 of the ferrule 10 and the flat plate 30 using capillary action. Agent). Here, an ultraviolet curable adhesive is used as the refractive index matching agent, and when the ultraviolet light is irradiated through the flat plate 30 after penetrating the adhesive inside, the adhesive is cured and the end face of the lensed fiber 1 is flat. Glued to 30. Further, since the ultraviolet curable adhesive permeates between the end face 11 of the ferrule 10 and the flat plate 30, the flat plate 30 is bonded to the end face 11 of the ferrule 10 when the ultraviolet ray is irradiated through the flat plate 30. A thermosetting adhesive may be used instead of the ultraviolet curable adhesive. In addition, the operator fixes the lensed fiber 1 to the ferrule 10 by filling the ferrule 10 with an adhesive from the adhesive filling window 16.

  The ferrule 10 with an optical fiber is manufactured by the above operation. In addition, when the ferrule 10 with an optical fiber manufactured as described above is optically connected by being opposed to each other as shown in FIG. 1, it is possible to realize an optical loss of about 0.7 dB and a return loss of about 60 dB. It is.

  In the optical connector system 20 (see FIG. 3A) of the first embodiment, the two ferrules 10 are arranged to face each other, and the ferrules 10 come into contact with the spacers 23, so that the flat plates 30 are spaced from each other at a predetermined interval. Opposed to each other. Thereby, as shown in FIG. 1, the flat plates 30 are aligned in the front-rear direction, and the lensed fibers 1 of the two ferrules 10 can be optically connected. These ferrules 10 have a lensed fiber 1 and a flat plate 30. The flat plate 30 is in a state in which the end face of the lensed fiber 1 inserted into the fiber hole 15 is abutted against the lensed fiber 1. It is arranged to be inclined with respect to a plane perpendicular to the optical axis. Since the flat plate 30 is inclined and the MFD (Mode Field Diameter) of the optical signal is large by the GRIN lens 3, the optical loss can be suppressed and it is not necessary to form a lens on the ferrule 10. Easy to manufacture. In addition, since the flat plate 30 is simply disposed at an inclination, a process for polishing the end face of the ferrule 10 obliquely is not necessary.

=== Second Embodiment ===
In 1st Embodiment, the adhesive agent used as a refractive index matching agent was apply | coated to the boundary of the end surface 11 and the flat plate 30 of the ferrule 10, and the adhesive agent was penetrated inside by the capillary phenomenon. However, the filling method of the refractive index matching agent is not limited to this.

  FIG. 5A is a perspective view of the ferrule 10 of the second embodiment. FIG. 5B is an explanatory diagram of a state when the adhesive (refractive index matching agent) is filled in the second embodiment.

A recess 17 is formed in the front end face 11 of the ferrule 10 of the second embodiment. The recess 17 is a part that is recessed from the front end face 11 and forms a space that is filled with an adhesive serving as a refractive index matching agent. In the recess 17, a fiber hole opening surface 17A, a bottom surface 17B, and a side surface 17C are formed.
The fiber hole opening surface 17 </ b> A is an inner wall on the rear side in the recess 17 and is located on the rear side with respect to the end surface 11 of the ferrule 10. The fiber hole opening surface 17A is a surface facing the inner surface of the flat plate 30, and a plurality of fiber holes 15 are opened side by side in the left-right direction on the fiber opening surface.
The bottom surface 17 </ b> B is an inner wall that forms the bottom of the recess 17. Here, a fiber groove is formed on the bottom surface 17B, and the lensed fiber 1 inserted into the fiber hole 15 is supported on the fiber groove from the bottom surface 17B (see FIG. 5B). As a result, the end of the lensed fiber 1 does not have to bend in the recess 17.

  In 2nd Embodiment, an operator arrange | positions the flat plate 30 in the end surface 11 of the ferrule 10, as shown to FIG. 5A (refer S102 of FIG. 4). Next, the operator adheres the lensed fiber 1 and the flat plate 30 to the ferrule 10 (see S103). Also in the second embodiment, when the lensed fiber 1 and the flat plate 30 are bonded to the ferrule 10, the end face of the lensed fiber 1 is in contact with the flat plate 30. However, in the second embodiment, the operator fills the space surrounded by the flat plate 30 and the recess 17 with an adhesive serving as a refractive index matching agent. That is, an adhesive serving as a refractive index matching agent is filled in the space surrounded by the flat plate 30, the fiber hole opening surface 17A, the bottom surface 17B, and the side surface 17C. According to the second embodiment, since the refractive index matching agent (adhesive) is filled in the recess 17, the end faces of the flat plate 30 and the lensed fiber 1 are compared with the case where the adhesive is infiltrated using capillary action. The time for filling the refractive index matching agent in between can be shortened.

<Modification of Second Embodiment>
FIG. 6 is a perspective view of a ferrule 10 of a modified example of the second embodiment. FIG. 7 is an explanatory diagram of a ferrule 10 according to a modification of the second embodiment. In FIG. 7, for the sake of explanation, the ferrule 10 in the side view is shown with a partial cross section, and the lensed fiber 1 is inserted into the fiber hole 15.

  The ferrule 10 of the modified example has fiber holes 15 arranged two-dimensionally. Here, twelve rows of fiber holes 15 arranged in the left-right direction are arranged in four rows in the up-down direction. When the plurality of optical fiber holes 15 are two-dimensionally arranged, when the end surface 11 of the ferrule 10 is viewed from the front side, the center position (center of gravity position) of the plurality of fiber holes 15 is a figure with respect to the positioning hole 13. It may be shifted downward by an amount corresponding to 1 G / 2. That is, the end surface 11A is inclined so that the upper side (adhesive filling window 16 side) is directed toward the mating ferrule, and the center position of the plurality of fiber holes 15 is lower (adhesive). It may be in a position shifted to the side opposite to the agent filling window 16 side.

  Also in the modification, a recess 17 is formed in the front end face 11 of the ferrule 10. The recess 17 is formed with a fiber hole opening surface 17A, a bottom surface 17B, and a side surface 17C, and in a modified example, a protrusion 17D is further formed. The protruding portion 17D is a portion that protrudes from the upper edge of the fiber hole opening surface 17A to the front side (the flat plate 30 side), and is a portion that contacts the upper edge of the flat plate 30. The left and right edges and the lower edge of the flat plate 30 are in contact with the end surface 11 of the ferrule 10, and the upper edge of the flat plate 30 is in contact with the protruding portion 17D. Thereby, distortion of the flat plate 30 by shrinkage | contraction of the adhesive agent with which the recess 17 was filled can be suppressed. In particular, in the modified example, since the plurality of fiber holes 15 are two-dimensionally arranged, the recess 17 is formed deeply, so that the influence on the flat plate 30 due to the shrinkage of the adhesive is increased. It is particularly effective to form

=== Third Embodiment ===
FIG. 8A is a perspective view of the ferrule 10 of the third embodiment. FIG. 8B is an explanatory diagram of a state when the adhesive (refractive index matching agent) is filled in the third embodiment.

  A groove 18 is formed on the front end face of the ferrule 10 of the third embodiment. The groove 18 is formed along the left-right direction so as to penetrate the upper part of the openings of the plurality of fiber holes 15. As shown in FIG. 8B, the groove 18 has a V-shaped cross section, and has a lower surface 18A and an inclined surface 18B. The lower surface 18A is located near the center of the openings of the plurality of fiber holes 15. The inclined surface 18 </ b> B is an inner wall surface constituting the groove 18, and at least a part thereof is positioned above the fiber hole 15. The lower edge (rear edge) of the slope 18B is located at the rear edge of the lower surface 18A, and the upper edge (front edge: edge at the end face 11 of the ferrule 10) is located above the fiber hole 15.

  The end of the groove 18 is exposed outside the flat plate 30. Here, the left and right ends of the groove 18 are formed to extend to the upper surface of the ferrule 10 so that the left and right ends of the groove 18 are exposed above the flat plate 30. Thereby, the clearance gap 18C by the groove | channel 18 is formed in the boundary of the end surface 11 of the ferrule 10, and the flat plate 30, and an adhesive agent can be filled from this clearance gap 18C.

  In 3rd Embodiment, an operator arrange | positions the flat plate 30 in the end surface 11 of the ferrule 10, as shown to FIG. 8A (refer S102 of FIG. 4). Next, the operator adheres the lensed fiber 1 and the flat plate 30 to the ferrule 10 (see S103). Also in the third embodiment, when the lensed fiber 1 and the flat plate 30 are bonded to the ferrule 10, the end face of the lensed fiber 1 is in contact with the flat plate 30. However, in the third embodiment, the operator fills the adhesive from one of the two gaps 18 </ b> C formed by the groove 18 at the boundary between the end surface 11 of the ferrule 10 and the flat plate 30. The adhesive flows into the inside along the groove 18 and is filled therein. At this time, even if bubbles are formed inside, the bubbles move to the upper side of the fiber hole 15, so that formation of bubbles on the end face of the lensed fiber 1 can be suppressed.

<Modification of Third Embodiment>
FIG. 9 is an explanatory diagram of a ferrule 10 according to a modification of the third embodiment. FIG. 10A is an explanatory diagram of a state when an adhesive (refractive index matching agent) is filled in a modified example of the third embodiment.

  The ferrule 10 of the modified example has fiber holes 15 arranged two-dimensionally. Here, twelve rows of fiber holes 15 arranged in the left-right direction are arranged in four rows in the up-down direction. When the plurality of optical fiber holes 15 are two-dimensionally arranged, when the end surface 11 of the ferrule 10 is viewed from the front side, the center position (center of gravity position) of the plurality of fiber holes 15 is a figure with respect to the positioning hole 13. It may be shifted downward by an amount corresponding to 1 G / 2.

  Also in the modification, the groove 18 is formed along the left-right direction so as to penetrate the upper part of the openings of the plurality of fiber holes 15 arranged in the left-right direction. In the modified example, since the rows of fiber holes 15 arranged in the left-right direction are arranged in four rows in the vertical direction, the grooves 18 are also formed in four rows in the vertical direction. The left and right ends of the groove 18 are formed to extend until reaching the side surface of the ferrule 10. Thereby, the clearance gap 18C by the groove | channel 18 is formed in the boundary of the end surface 11 of the ferrule 10, and the flat plate 30, and an adhesive agent can be filled from this clearance gap 18C. Since the gap 18 </ b> C is formed in each of the four rows of grooves 18, it is possible to continue flowing the adhesive into each groove 18. If the left and right gaps 18C of the four rows of grooves 18 are made common (if the adhesive is branched from the common gap 18C and poured into the four rows of grooves 18), the adhesive A groove 18 that is difficult to flow is generated. For this reason, it is desirable that a gap 18 </ b> C be formed in each of the four rows of grooves 18.

  FIG. 10B is an explanatory diagram at the time of optical connection in the optical connector system having the ferrule 10 of a modification of the third embodiment. Also in the modified example, when the ferrule 10 contacts the spacer 23, the end surfaces 11 of the ferrule 10 are arranged to face each other at a predetermined interval L.

  In the modification, the left and right ends of the groove 18 are formed to extend until reaching the side surface of the ferrule 10. For this reason, if the spacer 23 comes into contact with the end surface 11 of the ferrule 10 at the portion where the groove 18 is formed, the spacer 23 may be rattled. In this case, the positional relationship between the ferrules 10 and the flat plates 30 The positional relationship in the front-rear direction may be shifted. Therefore, in the modification, the recess 23A is formed in the spacer 23 so as not to contact the portion where the groove 18 is formed. Thereby, the position in the front-rear direction between the ferrules 10 and the position in the front-rear direction between the flat plates 30 can be accurately matched.

=== Fourth Embodiment ===
In the first to third embodiments, a fluid refractive index matching agent (adhesive) is filled in the gap between the lensed fiber 1 and the flat plate 30. However, in this case, bubbles may be formed on the end face of the lensed fiber 1. On the other hand, in the fourth embodiment, a soft solid refractive index matching agent (solid refractive index matching material) is disposed on the flat plate 30, and the lensed fiber 1 is abutted against the soft solid refractive index matching material, thereby providing a lens. The formation of bubbles on the end face of the fiber 1 is suppressed.

  FIG. 11 is a flowchart of the manufacturing method of the ferrule 10 with an optical fiber of the fourth embodiment.

  First, a lensed fiber is created (S201). The process of S201 is the same as the process of S101 of FIG.

  Next, an operator arrange | positions a solid refractive index matching material between the ferrule 10 and the flat plate 30 (S202). The solid refractive index matching material is a light-transmitting sheet-like member, and is a solid refractive index matching agent. The refractive index of the solid refractive index matching material is almost the same as that of the above-mentioned adhesive (refractive index matching agent). Examples of materials for the solid refractive index matching material include acrylic, epoxy, vinyl, silicone, rubber, urethane, methacrylic, nylon, bisphenol, diol, polyimide, fluorinated epoxy, and fluorine. And polymer materials such as fluorinated acrylics.

  The solid refractive index matching material is disposed on the rear surface of the flat plate 30. That is, the solid refractive index matching material is disposed on the surface against which the lensed fiber 1 is abutted. For this reason, the solid refractive index matching material faces the opening of the fiber hole 15. For example, a sheet-like (film-like) solid refractive index matching material is attached to a region facing the fiber hole 15 on the surface of the flat plate 30 in FIG. The solid refractive index matching material is arranged on the flat plate 30 by solidifying after applying a liquid refractive index matching agent to the flat plate 30 instead of sticking the sheet-like solid refractive index matching material to the flat plate 30. Also good.

  The solid refractive index matching material has such a hardness that the surface is deformed when the end face of the lensed fiber 1 is abutted against it. Thereby, it is possible to suppress the formation of bubbles on the end face of the lensed fiber 1.

  FIG. 12 is an explanatory diagram of the relationship between the hardness and thickness of the solid refractive index matching material sheet. The horizontal axis indicates the thickness of the solid refractive index matching material, and the vertical axis indicates the Shore A hardness (HSA). As the solid refractive index matching material, those in the region RD in the figure can be suitably used. Note that the region RC and the region RD in the figure are separated by a straight line connecting the point P1 (HSA 70, thickness 50 μm) and the point P2 (HSA0, thickness 150 μm).

  In the region RA (region where the Shore A hardness is greater than 70), the hardness is too high, and the followability of the surface of the solid refractive index matching material when the lensed fiber 1 is abutted is low. For this reason, a gap (bubble) is likely to be generated on the end face of the lensed fiber 1. However, even when the solid refractive index matching material in the region RA is used, bubbles on the end face of the lensed fiber 1 can be suppressed as compared with the case where there is no solid refractive index matching material.

  In the region RB (the region where the Shore A hardness is 70 or less and the thickness is smaller than 30 μm), since the solid refractive index matching material is too thin, the end surface of the lensed fiber 1 is rough, or a plurality of lensed fibers. If the end faces of 1 are not aligned, gaps (bubbles) are likely to be generated on the end face of the lensed fiber 1. However, even when the solid refractive index matching material in the region RB is used, bubbles at the end face of the lensed fiber 1 can be suppressed as compared with the case where there is no solid refractive index matching material.

  In the region RC (the region where the Shore A hardness is 70 or less and the thickness is larger than the straight line connecting the points P1 and P2), the distance between the end surface of the lensed fiber 1 and the surface of the flat plate 30 becomes too large. It is not appropriate. However, even when the solid refractive index matching material in the region RC is used, bubbles at the end face of the lensed fiber 1 can be suppressed as compared with the case where there is no solid refractive index matching material.

  As described above, the region RD (the region having a Shore A hardness of 70 or less and a thickness of 30 μm or more, including a straight line connecting the points P1 and P2 and having a smaller thickness than the straight line) is appropriate. It becomes an area. That is, as a solid refractive index matching material, a range surrounded by four points (HSA0, thickness 30 μm), (HSA70, thickness 30 μm), (HSA70, thickness 50 μm), and (HSA0, thickness 150 μm) in the figure. It is desirable to use what is inside.

  It is desirable that both surfaces of the solid refractive index matching material have adhesiveness. This makes it difficult for the solid refractive index matching material to peel off from the flat plate 30, and after the end surface of the lensed fiber 1 is abutted against the solid refractive index matching material, the solid refractive index matching material and the end surface of the lensed fiber are separated. It becomes difficult to peel. As such a solid refractive index matching material, an adhesive material made of a polymer material in the form of a film can be used. From the standpoint of environmental resistance and adhesiveness, silicone-based and acrylic-based materials are generally used. Can be used.

  Next, the operator bonds the lensed fiber 1 and the flat plate 30 to the ferrule 10 (S203). In 4th Embodiment, when the lensed fiber 1 and the flat plate 30 are adhere | attached on the ferrule 10, the end surface of the lensed fiber 1 will be abutted and contacted to the flat plate 30 through the solid refractive index matching agent. Yes. When the end surface of the lensed fiber 1 is brought into contact with the solid refractive index matching material of the flat plate 30, the end surface of the lensed fiber 1 is perpendicular to the optical axis, and the flat plate 30 is perpendicular to the surface perpendicular to the optical axis. Although tilted, the surface of the solid refractive index matching material is deformed along the end surface of the lensed fiber 1, so that the gap between the end surface of the lensed fiber 1 and the flat plate 30 is filled with the solid refractive index matching material. Is done. The operator adheres the lensed fiber 1 and the flat plate 30 to the ferrule 10 by, for example, filling the recess 17 with an adhesive. Further, the lens-filled fiber 1 is fixed to the ferrule 10 by filling the adhesive filling window 16 with an adhesive. Thereby, the ferrule 10 with an optical fiber is manufactured.

  According to said 4th Embodiment, it can suppress that a bubble is formed in the end surface of the lensed fiber 1 by abutting the lensed fiber 1 to the soft solid refractive index matching material arrange | positioned at the flat plate 30. FIG.

=== Fifth Embodiment ===
FIG. 13A is an explanatory diagram of the ferrule 10 of the fifth embodiment. Also in the fifth embodiment, the front end surface 11 of the ferrule 10 is perpendicular to the optical axis of the lensed fiber 1 (the surface perpendicular to the axial direction of the fiber hole 15), as in the previous embodiment. Inclined. The flat plate 30 attached to the end surface 11 is also inclined with respect to a plane perpendicular to the optical axis of the lensed fiber 1.

  In the fifth embodiment, the front end face 11 of the ferrule 10 is viewed from above (a direction perpendicular to the left-right direction in which the two positioning holes 15 are aligned and the front-rear direction that is the axial direction of the positioning holes 15 (up-down direction). ) When tilted by 8 degrees with respect to the left-right direction. For this reason, the flat plate 30 attached to the end surface 11 is also inclined by 8 degrees with respect to the left-right direction when viewed from above.

  FIG. 13B is an explanatory diagram of a state when the ferrule 10 of the fifth embodiment is optically connected. Also in the fifth embodiment, the end faces 11 of the ferrule 10 are arranged to face each other, and the flat plates 30 are arranged to face each other. By inserting the positioning pin 14 into the positioning hole 13 of the ferrule 10, the ferrules 10 are aligned in a direction (left-right direction and up-down direction) perpendicular to the positioning pin 14 in an adapter (not shown).

  In the fifth embodiment, the upper and lower directions of the ferrule 10 are made the same (the adhesive filling window 16 is made the same direction) so that the inclined end surfaces 11 of the ferrule 10 are parallel to each other. Are facing each other. For this reason, in the fifth embodiment, the vertical position of the fiber hole 15 is the same as the vertical position of the positioning hole 13 (however, in the fifth embodiment, the plurality of fiber holes 15 are positioned on one side. The side of the hole 13 is shifted in the left-right direction by an amount corresponding to G / 2 in FIG. 1).

  Also in the fifth embodiment, when the ferrule 10 contacts the spacer 23, the end faces 11 of the ferrule 10 are arranged to face each other at a predetermined interval L, and the flat plates 30 are arranged to face each other at a predetermined interval. Is done. That is, when the ferrule 10 contacts the spacer 23, the ferrules 10 are aligned in the front-rear direction, and the flat plates 30 are aligned in the front-rear direction.

=== Sixth Embodiment ===
FIG. 14A is an explanatory diagram of the ferrule 10 of the sixth embodiment.
In the sixth embodiment, the front end surface 11 of the ferrule 10 is a surface perpendicular to the axial direction (front-rear direction) of the positioning hole 13 and is not inclined. However, in the sixth embodiment, the axial direction of the fiber hole 15 is inclined by 8 degrees with respect to the axial direction of the positioning hole 13. For this reason, when the lensed fiber 1 is inserted into the fiber hole 15, the front end face 11 of the ferrule 10 is inclined with respect to a plane perpendicular to the optical axis of the lensed fiber 1. Further, the flat plate 30 attached to the end face 11 is also arranged to be inclined with respect to a plane perpendicular to the optical axis of the lensed fiber 1.

  FIG. 14B is an explanatory diagram of a state when the ferrule 10 of the sixth embodiment is optically connected. Also in the sixth embodiment, the end faces 11 of the ferrule 10 are arranged to face each other, and the flat plates 30 are arranged to face each other. By inserting the positioning pin 14 into the positioning hole 13 of the ferrule 10, the ferrules 10 are aligned in a direction (left-right direction and up-down direction) perpendicular to the positioning pin 14 in an adapter (not shown). In the sixth embodiment, the ferrule 10 is made to have the same vertical direction (the adhesive filling window 16 is made to have the same orientation) so that the fiber holes 15 of the opposing ferrules 10 are parallel to each other. 10 are opposed to each other.

  Also in the sixth embodiment, when the ferrule 10 contacts the spacer 23, the end faces 11 of the ferrule 10 face each other at a predetermined interval L (not an interval in the front-rear direction but an interval in the optical axis direction of the lensed fiber 1). The flat plates 30 are arranged to face each other at a predetermined interval. That is, when the ferrule 10 contacts the spacer 23, the ferrules 10 are aligned in the front-rear direction, and the flat plates 30 are aligned in the front-rear direction. In the sixth embodiment, the thickness of the spacer 23 in the front-rear direction is slightly smaller than L.

=== Others ===
The above-described embodiments are for facilitating the understanding of the present invention, and are not intended to limit the present invention. The present invention can be modified and improved without departing from the gist thereof, and it goes without saying that the present invention includes equivalents thereof.

1 lensed fiber,
2 single mode optical fiber,
3 GRIN lens,
10 Ferrule,
11 End face,
12 Buttocks,
13 Positioning hole,
14 locating pins,
15 Fiber hole,
16 Adhesive filling window,
17 Recess,
17A Fiber hole opening surface,
17B Bottom,
17C side,
17D protrusion,
18 grooves,
18A bottom surface,
18B slope,
18C clearance,
20 optical connector system,
21 optical connector,
22 adapter,
23 spacer,
23A recess,
30 flat plate

Claims (10)

A ferrule having a plurality of fiber holes;
A lensed fiber having a GRIN lens fused and connected to the tip of the optical fiber;
A flat plate capable of transmitting light propagating through the optical fiber, the flat plate being attached to the end face of the ferrule and abutting the end face of the lensed fiber inserted into the fiber hole;
Have
The end face and the flat plate of the ferrule are inclined with respect to a plane perpendicular to the optical axis of the lensed fiber inserted into the fiber hole,
A ferrule with a fiber, wherein a refractive index matching agent is filled in a gap between an end face of the lensed fiber and the flat plate. The ferrule with a fiber according to claim 1,
A ferrule with a fiber, wherein an antireflection film is formed on an outer surface of the flat plate. A ferrule with a fiber according to claim 1 or 2,
The ferrule has a recess recessed from the end face of the ferrule,
A ferrule with a fiber, wherein the space surrounded by the flat plate and the recess is filled with the refractive index matching agent. A ferrule with a fiber according to claim 3,
A ferrule with a fiber, wherein a fiber groove for supporting the lensed fiber is formed on a bottom surface of the recess. A ferrule with a fiber according to claim 3 or 4,
The recess is formed with a fiber hole opening surface facing the inner surface of the flat plate, and a plurality of the fiber holes are opened,
A ferrule with a fiber, characterized in that a protruding portion that protrudes from the fiber hole opening surface toward the flat plate and contacts with an edge of the flat plate is formed. A ferrule with a fiber according to claim 1 or 2,
On the end face of the ferrule, a groove formed so as to penetrate the upper part of the openings of the plurality of fiber holes is formed,
A ferrule with a fiber, wherein at least a part of an inner wall surface constituting the groove is positioned above the fiber hole. A ferrule with a fiber according to any one of claims 1 to 6,
A ferrule with a fiber, characterized in that a solid refractive index matching material whose surface is deformed when an end face of the lensed fiber is abutted against the inner surface of the flat plate. A ferrule with a fiber according to claim 7,
A ferrule with a fiber, wherein both surfaces of the solid refractive index matching material have adhesiveness. A ferrule with a fiber according to claim 7 or 8,
The Shore A hardness and thickness of the solid refractive index matching material are
The point where the Shore A hardness is 0 and the thickness is 30 μm,
A point with a Shore A hardness of 70 and a thickness of 30 μm,
A point with a Shore A hardness of 70 and a thickness of 50 μm,
A ferrule with a fiber, wherein the Shore A hardness is 0 and the thickness is within a range surrounded by four points of 150 μm. An optical connector system having an adapter and two optical connectors inserted on both sides of the adapter,
Each said optical connector is
A ferrule having a plurality of fiber holes;
A lensed fiber having a GRIN lens fused and connected to the tip of the optical fiber;
A flat plate capable of transmitting light propagating through the optical fiber, the flat plate being attached to the end face of the ferrule and abutting the end face of the lensed fiber inserted into the fiber hole;
Have
The end face and the flat plate of the ferrule are inclined with respect to a plane perpendicular to the optical axis of the lensed fiber inserted into the fiber hole,
The gap between the end face of the lensed fiber and the flat plate is filled with a refractive index matching agent,
The adapter has a spacer protruding inward,
An optical connector system, wherein the ferrule contacts the spacer inside the adapter so that the end faces of the ferrule are arranged to face each other at a predetermined interval.

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