JP2010237330A - Connection structure of optical fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress amplification of reflected light between a pair of end faces, and to keep down the connection loss of a pair of optical fibers. <P>SOLUTION: In this connection structure 10 of the optical fibers, end faces 20A and 22A on mutual abutting sides in the pair of optical fibers 20 and 22 face each other in a non-parallel state. Therefore, multiple reflection between the pair of end faces 20A and 22A can be suppressed, so that the amplification of the reflected light between the pair of end faces 20A and 22A can be suppressed. The pair of end faces 20A and 22A partially abut on each other and are close to each other, so that the connection loss of the pair of optical fibers 20 and 22 can be kept down. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical fiber connection structure.

  Conventionally, the following is known as an optical fiber connection structure (see, for example, Patent Document 1). That is, in the example described in Patent Document 1, the pair of optical fibers are optically connected in a state where the end surfaces on the abutting side face each other in the optical axis direction.

Japanese Patent No. 3515305

  However, in such an optical fiber connection structure, when the end surfaces of the pair of optical fibers on the abutting side are cut perpendicular to the optical axis, even if there is a minute reflection between the pair of end surfaces There is a possibility of interference of light due to reflection, and the reflected light may be amplified at wavelengths that are strengthened by this interference.

  Further, even when the pair of end faces are cut in a state inclined with respect to the direction perpendicular to the optical axis, if the inclination angles of the pair of end faces are the same, Since the distance is shortened, light interference due to multiple reflection occurs between the pair of end faces in the same manner as described above, and the reflected light may be amplified.

  In addition, when the pair of end faces are separated from each other in the optical axis direction, the connection loss between the pair of optical fibers increases.

  The present invention has been made in view of the above-described problems, and can suppress the amplification of reflected light between the end faces of the pair of optical fibers on the abutting side, and reduce the connection loss of the pair of optical fibers. An object of the present invention is to provide an optical fiber connection structure that can be suppressed.

  In order to solve the above-described problem, the optical fiber connection structure according to claim 1 includes a pair of optical fibers that are abutted so that their optical axes coincide with each other, and each abutment side of the pair of optical fibers. These end faces are formed in a planar shape and are opposed to each other in a non-parallel state, and are partially in contact with each other.

  In addition, the planar shape in this case is intended to include not only a completely flat surface without unevenness but also some unevenness that inevitably occurs during manufacturing.

  According to this optical fiber connection structure, the end surfaces of the pair of optical fibers on the abutting side face each other in a non-parallel state. Accordingly, multiple reflections between the pair of end surfaces can be suppressed, so that the reflected light can be prevented from being amplified between the pair of end surfaces. In addition, since the pair of end faces are in contact with each other and are close to each other, the connection loss between the pair of optical fibers can be kept low.

  An optical fiber connection structure according to claim 2 is the optical fiber connection structure according to claim 1, wherein a refractive index matching agent is interposed between the pair of end faces.

  According to this optical fiber connection structure, reflection of light at each end face can be suppressed by the refractive index matching agent.

  The optical fiber connection structure according to claim 3 is the optical fiber connection structure according to claim 1 or 2, wherein an interval between the pair of end faces on the optical axis is 10 μm or less. is there.

  Here, in this optical fiber connection structure, if the distance between the pair of end faces on the optical axis is larger than 10 μm, there is a possibility that bubbles may enter the gap between the pair of end faces.

  However, according to this optical fiber connection structure, since the distance on the optical axis between the pair of end faces is 10 μm or less, it is possible to prevent bubbles from entering the gap between the pair of end faces.

  The optical fiber connection structure according to claim 4 is the optical fiber connection structure according to claim 1 or 2, wherein an interval between the pair of end faces on the optical axis is 5 μm or less. is there.

  Here, in this optical fiber connection structure, when the distance between the pair of end faces on the optical axis is larger than 5 μm, the connection loss between the pair of optical fibers increases.

  However, according to this optical fiber connection structure, since the distance on the optical axis between the pair of end faces is 5 μm or less, the connection loss of the pair of optical fibers can be kept low.

  The optical fiber connection structure according to claim 5 is the optical fiber connection structure according to any one of claims 1 to 4, wherein one of the pair of end faces is perpendicular to the optical axis. The other of the pair of end faces is inclined with respect to a direction perpendicular to the optical axis.

  According to this optical fiber connection structure, one of the pair of end faces is perpendicular to the optical axis of the pair of optical fibers, and the other of the pair of end faces is perpendicular to the optical axis of the pair of optical fibers. Since it is inclined, the pair of end faces face each other in a non-parallel state.

  The optical fiber connection structure according to claim 6 is the optical fiber connection structure according to any one of claims 1 to 4, wherein the pair of end faces are perpendicular to the optical axis. They are inclined at different angles.

  According to this optical fiber connection structure, since the pair of end faces are inclined at different angles with respect to the direction perpendicular to the optical axis of the pair of optical fibers, the pair of end faces face each other in a non-parallel state. .

  Here, in order to incline the pair of end faces at different angles with respect to the direction perpendicular to the optical axis of the pair of optical fibers, for example, the following configuration is preferable.

  That is, in the optical fiber connection structure according to claim 7, the pair of end faces are cut at different inclination angles with respect to the direction perpendicular to the optical axis, so that the direction perpendicular to the optical axis is obtained. Are inclined at different angles.

  9. The optical fiber connection structure according to claim 8, wherein the pair of end faces are cut so that inclination angles with respect to a direction perpendicular to the optical axis are the same, and at least one of the pair of optical fibers. Is relatively rotated about the optical axis with respect to the other, thereby being inclined at different angles with respect to a direction perpendicular to the optical axis.

  The optical fiber connection structure according to claim 9, wherein the pair of end faces are cut so that inclination angles with respect to a direction perpendicular to the optical axis are different from each other, and at least one of the pair of optical fibers is By being relatively rotated around the optical axis with respect to the other, they are inclined at different angles with respect to a direction perpendicular to the optical axis.

  The optical fiber connection structure according to claim 10 is the optical fiber connection structure according to any one of claims 1 to 9, further comprising a holder for holding the pair of optical fibers.

  According to this optical fiber connection structure, the pair of optical fibers can be held by the holder.

  In addition, as this holder, when it is set as the following, for example, it is suitable.

  That is, in the optical fiber connection structure according to claim 11, the holder includes a substrate on which a holding groove for holding the pair of optical fibers is formed, and a lid that holds the pair of optical fibers between the substrate. And a pressing member that presses the lid toward the substrate.

  The optical fiber connection structure according to claim 12, wherein the holder includes a substrate on which a holding groove for holding the pair of optical fibers is formed, and a lid that holds the pair of optical fibers between the substrate. And a pressing member that presses the lid toward the substrate, and a ferrule in which any one of the pair of optical fibers is built and supported by the substrate.

  In this case, it is more preferable that the end face of the optical fiber built in the ferrule is inclined with respect to the direction perpendicular to the optical axis as in the optical fiber connection structure according to claim 13. .

  The optical fiber connection structure according to claim 14, wherein the holder includes a first ferrule that holds a plurality of one of the pair of optical fibers arranged in parallel, and the other of the pair of optical fibers. It is set as the MT-type connector provided with the 2nd ferrule connected with the said 1st ferrule, hold | maintained in the state arrange | positioned in parallel.

  As described above in detail, according to the present invention, it is possible to suppress the reflection light from being amplified between the end faces of the pair of optical fibers on the abutting side, and to suppress the connection loss of the pair of optical fibers to be low. it can.

It is a perspective view of the mechanical splice which concerns on 1st embodiment of this invention. It is the sectional view on the AA line of FIG. It is side surface sectional drawing of the connection structure of the optical fiber applied to the mechanical splice of FIG. It is a figure which shows the relationship between the space | interval Z and inclination-angle (theta) in the connection structure of the optical fiber of FIG. It is side surface sectional drawing of the connection structure of the optical fiber which concerns on 2nd embodiment of this invention. It is side surface sectional drawing of the connection structure of the optical fiber which concerns on 3rd embodiment of this invention. It is a figure explaining the procedure for obtaining the connection structure of the optical fiber shown by FIG. It is a figure which shows the relationship between the space | interval Z and the rotation angle (phi) in the connection structure of the optical fiber of FIG. It is a perspective view of the field attachment optical connector which concerns on 4th embodiment of this invention. It is the BB sectional view taken on the line of FIG. 8A. It is a disassembled perspective view of MT type connector which concerns on 5th embodiment of this invention. FIG. 9B is a side view of the MT connector shown in FIG. 9A. It is side surface sectional drawing of the connection structure of the optical fiber which concerns on a 1st comparative example. It is side surface sectional drawing of the connection structure of the optical fiber which concerns on a 2nd comparative example.

[First embodiment]
First, a first embodiment of the present invention will be described.

  As shown in FIG. 1A, a mechanical splice 60 as a holder according to the first embodiment of the present invention includes a substrate 12, a plurality of lids 14, and a plurality of pressing members 16.

  As shown in FIG. 1B, the substrate 12 has a holding surface 12A, and a holding groove 18 having a V-shaped cross section is formed on the holding surface 12A. The holding groove 18 is for holding the pair of optical fibers 20 and 22 shown in FIG. 1A in a state where they are abutted so that their optical axes coincide with each other, and is formed along the longitudinal direction of the substrate 12. ing. The plurality of lids 14 are arranged side by side in the optical axis direction of the pair of optical fibers 20 and 22 and are provided to face the holding surface 12A so as to cover the holding surface 12A, respectively.

  As shown in FIG. 1B, each pressing member 16 is configured by a U-shaped spring having a pair of support pieces 24 and 26 and a connecting portion 28 for connecting the support pieces 24 and 26. Each lid 14 is pressed toward the substrate 12 side.

  In the mechanical splice 60, when the wedges 32 are respectively inserted into the groove portions 29 formed in the substrate 12 and the lids 14, the lids 14 are separated from the substrate 12, and the pair of optical fibers 20 and 22 are connected. The holding groove 18 can be inserted into the holding groove 18 from both sides in the longitudinal direction.

  Further, when the wedge 32 is removed from the groove portion 29 in a state where the pair of optical fibers 20 and 22 are inserted into the holding groove 18, each lid 14 is pressed toward the substrate 12 by each pressing member 16. Optical fibers 20 and 22 are sandwiched between the substrate 12 and the plurality of lids 14. The pair of optical fibers 20 and 22 are optically connected as described above.

  Next, the optical fiber connection structure 10 in the mechanical splice 60 will be described.

  As shown in FIG. 2, the end surfaces 20A and 22A on the abutting side of the pair of optical fibers 20 and 22 are each formed in a planar shape. One end face 20A is cut perpendicular to the optical axis Ax, and the other end face 22A is cut so as to be inclined with respect to a direction perpendicular to the optical axis Ax.

  The pair of end surfaces 20A and 22A are opposed to each other in a non-parallel state, and a part (a lower portion in the drawing) is in contact with each other. Further, a refractive index matching agent 34 such as silicone grease is interposed between the pair of end faces 20A and 22A.

  Furthermore, the distance on the optical axis Ax between the pair of end faces 20A and 22A is 10 μm or less, preferably 5 μm or less.

  That is, the interval on the optical axis Ax between the pair of end faces 20A and 22A is Z, the inclination angle of the other end face 22A with respect to the direction perpendicular to the optical axis Ax is θ, and the radius of the pair of optical fibers 20 and 22 is r. In this case, the relationship Z = r × tan θ is established. The specific relationship between the interval Z and the inclination angle θ is as shown in FIG.

  That is, when the interval Z is 10 μm or less, the inclination angle θ is 9.0 ° or less, and when the interval Z is 5 μm or less, the inclination angle θ is 4.5 ° or less. The diameter of the pair of optical fibers 20 and 22 is 125 μm.

  Next, the operation and effect of the first embodiment of the present invention will be described.

  First, in order to clarify the operation and effect of the first embodiment of the present invention, a comparative example will be described.

  In the optical fiber connection structure 110 according to the first comparative example shown in FIG. 10, the pair of end faces 20A and 22A are cut perpendicular to the optical axis Ax. In this case, even if it is a minute reflection between the pair of end faces 20A and 22A, interference of light due to multiple reflection R occurs, and there is a possibility that the reflected light L is amplified at a wavelength strengthened by this interference. That is, if the distance between the pair of end faces 20A and 22A is d, the wavelength of light is λ, and n is an arbitrary natural number, 2d = nλ is a condition for strengthening the light.

  Further, in the optical fiber connection structure 210 according to the second comparative example shown in FIG. 11, the pair of end faces 20A and 22A are cut in a state inclined with respect to the direction perpendicular to the optical axis Ax. The inclination angles θ1, θ2 of the pair of end faces 20A, 22A are the same. In this case, since the distance between the pair of end faces 20A and 22A becomes short, light interference due to multiple reflection R occurs between the pair of end faces 20A and 22A, and the reflected light L may be amplified. There is.

  As shown in FIGS. 10 and 11, when the pair of end faces 20A and 22A are separated from each other in the optical axis direction, the connection loss between the pair of optical fibers 20 and 22 increases.

  On the other hand, according to the optical fiber connection structure 10 according to the first embodiment of the present invention, as shown in FIG. 2, the pair of end faces 20A and 22A face each other in a non-parallel state. Accordingly, multiple reflections between the pair of end surfaces 20A and 22A can be suppressed, so that the reflected light can be prevented from being amplified between the pair of end surfaces 20A and 22A. In addition, the pair of end surfaces 20A and 22A are partially in contact with each other and are close to each other, so that the connection loss between the pair of optical fibers 20 and 22 can be kept low.

  Further, according to the optical fiber connection structure 10, the refractive index matching agent 34 is interposed between the pair of end faces 20A and 22A. Therefore, reflection of light at the end faces 20A and 22A can be suppressed by the refractive index matching agent 34.

  Here, in this optical fiber connection structure 10, if the distance between the pair of end faces 20A, 22A on the optical axis Ax is larger than 10 μm, there is a possibility that bubbles may enter the gap between the pair of end faces 20A, 22A.

  However, according to this optical fiber connection structure 10, since the distance on the optical axis Ax between the pair of end faces 20A, 22A is 10 μm or less, bubbles enter the gap between the pair of end faces 20A, 22A. Can be suppressed.

  Further, in this optical fiber connection structure 10, if the distance between the pair of end faces 20A, 22A on the optical axis Ax is larger than 5 μm, the connection loss between the pair of optical fibers 20, 22 increases.

  However, according to this optical fiber connection structure 10, the distance between the pair of end faces 20A, 22A on the optical axis Ax is preferably 5 μm or less, so the connection loss between the pair of optical fibers 20, 22 is kept low. be able to.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.

  The optical fiber connection structure 40 according to the second embodiment of the present invention shown in FIG. 4 is modified as follows with respect to the optical fiber connection structure 10 according to the first embodiment of the present invention described above. Yes.

  That is, in the optical fiber connection structure 40, the pair of end faces 20A and 22A are cut at different inclination angles with respect to the direction perpendicular to the optical axis Ax, so that the direction perpendicular to the optical axis Ax is obtained. Are inclined at different angles. That is, the inclination angle θ1 of one end face 20A is different from the inclination angle θ2 of the other end face 22A.

  Further, in this optical fiber connection structure 40, the inclination angles (cutting angles) θ1 and θ2 are set so that the distance on the optical axis Ax between the pair of end faces 20A and 22A is 10 μm or less, preferably 5 μm or less. Has been.

  Also with this optical fiber connection structure 40, since the pair of end faces 20A, 22A are opposed to each other in a non-parallel state, multiple reflections between the pair of end faces 20A, 22A can be suppressed, and the pair of end faces It can suppress that reflected light is amplified between 20A and 22A. In addition, the pair of end faces 20A and 22A are partially in contact with each other and are close to each other, so that the connection loss between the pair of optical fibers 20 and 22 can be kept low.

[Third embodiment]
Next, a third embodiment of the present invention will be described.

  The optical fiber connection structure 50 according to the third embodiment of the present invention shown in FIG. 5 is modified as follows with respect to the optical fiber connection structure 10 according to the first embodiment of the present invention described above. Yes.

  That is, in this optical fiber connection structure 50, the pair of end faces 20A and 22A are cut so that the inclination angles with respect to the direction perpendicular to the optical axis Ax are the same as shown in the upper diagram of FIG. Yes. That is, the inclination angle θ1 of one end face 20A and the inclination angle θ2 of the other end face 22A are the same angle.

  Then, after the pair of optical fibers 20 and 22 are brought into contact with each other, the other optical fiber 22 is rotated around the optical axis Ax with respect to the one optical fiber 20 as shown in the lower diagram of FIG. By being rotated by the rotation angle φ, the pair of end faces 20A and 22A are inclined at different angles with respect to the direction perpendicular to the optical axis Ax.

  5 and 6, the pair of end surfaces 20A and 22A are not shown in a state where a part thereof is in contact with each other, but a part of the end surfaces 20A and 22A are in contact with each other in a part not shown in this figure. It is supposed to be in a state.

  Further, in this optical fiber connection structure 50, the inclination angles (cutting angles) θ1, θ2, and the like so that the distance on the optical axis Ax between the pair of end faces 20A, 22A is 10 μm or less, preferably 5 μm or less, and The rotation angle φ is set as appropriate.

  That is, the specific relationship among the interval Z, the inclination angles θ1 and θ2, and the rotation angle φ is as shown in FIG. 7, for example.

  That is, for example, when the inclination angles θ1 and θ2 are 10 °, if the interval Z is 10 μm or less, the rotation angle φ is about 50 ° or less, and if the interval Z is 5 μm or less, the rotation is The angle φ is about 25 ° or less.

  Further, for example, when the inclination angles θ1 and θ2 are 8 °, if the interval Z is 10 μm or less, the rotation angle φ is about 70 ° or less, and if the interval Z is 5 μm or less, the rotation is The angle φ is about 35 ° or less.

  Further, for example, when the inclination angles θ1 and θ2 are 6 °, if the interval Z is 10 μm or less, the rotation angle φ is about 100 ° or less, and if the interval Z is 5 μm or less, the rotation is The angle φ is about 40 ° or less.

  Also with this optical fiber connection structure 50, since the pair of end faces 20A, 22A are opposed to each other in a non-parallel state, multiple reflections between the pair of end faces 20A, 22A can be suppressed, and the pair of end faces It can suppress that reflected light is amplified between 20A and 22A. In addition, the pair of end faces 20A and 22A are partially in contact with each other and are close to each other, so that the connection loss between the pair of optical fibers 20 and 22 can be kept low.

  In this optical fiber connection structure 50, one optical fiber 20 is rotated around the optical axis Ax with respect to the other optical fiber 22, so that the pair of end faces 20A, 22A are perpendicular to the optical axis Ax. It may be inclined at different angles with respect to the direction. In addition, the pair of end faces 20A and 22A may be inclined at different angles with respect to the direction perpendicular to the optical axis Ax by rotating the pair of optical fibers 20 and 22 around the optical axis Ax.

  In the optical fiber connection structure 50, the pair of end faces 20A and 22A are cut so that the inclination angles θ1 and θ2 are different from each other, and at least one of the pair of optical fibers 20 and 22 is light with respect to the other. By being relatively rotated around the axis Ax, they may be inclined at different angles with respect to the direction perpendicular to the optical axis Ax.

  In the optical fiber connection structure 50, when the pair of optical fibers 20 and 22 are cut, if the inclination angles (cutting angles) θ1 and θ2 of the pair of end surfaces 20A and 22A vary, the pair of end surfaces 20A and 22A. The rotation angle φ may be appropriately adjusted so that multiple reflections can be suppressed.

[Fourth embodiment]
Next, a fourth embodiment of the present invention will be described.

  In the fourth embodiment of the present invention shown in FIGS. 8A and 8B, the above-described optical fiber connection structure 10 is applied to an on-site optical connector 70 as a holder.

  This on-site optical connector 70 includes a substrate 42, a lid 44, a pressing member 46, and a ferrule 47. In FIG. 8A, the lid 44 and the pressing member 46 shown in FIG. 8B are omitted from the on-site optical connector 70 and are shown.

  The board | substrate 42 is set as the structure which has integrally the board | substrate body 49 formed in plate shape, and the ferrule holder 52 comprised cyclically | annularly. A planar holding surface 42A is formed in the substrate body 49, and a holding groove 48 having a U-shaped cross section for holding the pair of optical fibers 20 and 22 is formed on the holding surface 42A in the longitudinal direction of the substrate body 49. It is formed along. Further, the ferrule holder 52 is located on one side in the longitudinal direction of the substrate body 49.

  The lid 44 has substantially the same shape as the substrate body 49 described above, and is provided to face the holding surface 42A so as to cover the holding surface 42A.

  The pressing member 46 is configured by a spring having a C-shaped cross section. The pressing member 46 accommodates a substrate body 49 and a lid 44 therein, and presses the lid 44 toward the substrate body 49 side.

  The ferrule 47 is supported by the substrate 42 by being inserted into a hole 54 formed in the ferrule holder 52. The ferrule 47 has a communication hole 56 that communicates with one side in the longitudinal direction of the holding groove 48, and one optical fiber 20 (bare fiber) is built into the communication hole 56. The rear end side of the one optical fiber 20 is inserted and held in the holding groove 48 from one side in the longitudinal direction.

  8B, when the wedge 62 is inserted into the groove 59 formed in the substrate main body 49 and the lid 44, the lid 44 is separated from the substrate main body 49. The other optical fiber 22 can be inserted into the holding groove 48 from the other side in the longitudinal direction of the holding groove 48.

  When the wedge 62 is removed from the groove 59 with the other optical fiber 22 inserted into the holding groove 48, the lid 44 is pressed toward the substrate body 49 by the pressing member 46, thereby a pair of optical fibers. 20 and 22 are sandwiched between the substrate body 49 and the lid 44. The pair of optical fibers 20 and 22 are optically connected as described above.

  In the field-attached optical connector 70, the end face 20A of the optical fiber 20 incorporated in the ferrule 47 is inclined in advance with respect to the optical axis. With such a configuration, at the connection site of the pair of optical fibers 20 and 22, the end surface 22A of the other optical fiber 22 does not have to be cut into a state inclined with respect to the direction perpendicular to the optical axis. The pair of end surfaces 20A and 22A can be in a non-parallel state.

  In the present embodiment, the optical fiber connection structure 10 according to the first embodiment of the present invention described above is applied to the on-site optical connector 70. The optical fiber connection structure 40 according to the second embodiment or the optical fiber connection structure 50 according to the third embodiment of the present invention may be applied.

[Fifth embodiment]
Next, a fifth embodiment of the present invention will be described.

  In the fifth embodiment of the present invention shown in FIGS. 9A and 9B, the above-described optical fiber connection structure 10 is applied to an MT connector 80 as a holder.

  That is, the MT connector 80 includes a first ferrule 72, a second ferrule 74, and a clip 76. The first ferrule 72 holds a plurality of optical fibers 20 arranged in parallel, and the second ferrule 74 holds a plurality of optical fibers 22 arranged in parallel.

  The second ferrule 74 is provided with a pair of pins 96 projecting along a direction parallel to the optical axis direction of the pair of optical fibers 20 and 22, and the first ferrule 72 is provided with the pair of pins 96. A hole (not shown) into which is inserted is formed.

  The first ferrule 72 and the second ferrule 74 are positioned with each other when the pair of pins 96 are inserted into the holes described above, and are connected in a pressed state by the clip 76. Thereby, each one optical fiber 20 and each other optical fiber 22 are abutted and optically connected so that their optical axes coincide with each other.

  In this embodiment, the optical fiber connection structure 10 according to the first embodiment of the present invention described above is applied to the MT connector 80. However, the second embodiment of the present invention described above is applied to this MT connector 80. The optical fiber connection structure 40 according to the embodiment or the optical fiber connection structure 50 according to the third embodiment of the present invention may be applied.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited above, Of course, it can change and implement variously within the range which does not deviate from the main point. .

10, 40, 50 Optical fiber connection structure 12, 42 Substrate 14, 44 Lid 16, 46 Press member 18 Holding groove 20, 22 Optical fiber 20A, 22A End face 34 Refractive index matching agent 47 Ferrule 60 Mechanical splice (holder)
70 On-site optical connector (holder)
72 1st ferrule 74 2nd ferrule 80 MT type connector (holder)

Claims (14)

Comprising a pair of optical fibers butted so that their optical axes coincide with each other;
The end faces of the pair of optical fibers on the abutting side are each formed in a flat shape and face each other in a non-parallel state, and are partially in contact with each other.
Optical fiber connection structure. A refractive index matching agent is interposed between the pair of end faces,
The optical fiber connection structure according to claim 1. An interval on the optical axis between the pair of end faces is 10 μm or less.
The optical fiber connection structure according to claim 2. An interval on the optical axis between the pair of end surfaces is 5 μm or less.
The optical fiber connection structure according to claim 1. One of the pair of end faces is perpendicular to the optical axis,
The other of the pair of end faces is inclined with respect to a direction perpendicular to the optical axis.
The connection structure of the optical fiber as described in any one of Claims 1-4. The pair of end faces are inclined at different angles with respect to a direction perpendicular to the optical axis.
The connection structure of the optical fiber as described in any one of Claims 1-4. The pair of end faces are inclined at different angles with respect to the direction perpendicular to the optical axis by being cut at different inclination angles with respect to the direction perpendicular to the optical axis.
The optical fiber connection structure according to claim 6. The pair of end faces are cut so that the inclination angles with respect to a direction perpendicular to the optical axis are the same, and at least one of the pair of optical fibers is relatively rotated around the optical axis with respect to the other. By being inclined at different angles with respect to the direction perpendicular to the optical axis,
The optical fiber connection structure according to claim 6. The pair of end faces are cut so that inclination angles with respect to a direction perpendicular to the optical axis are different from each other, and at least one of the pair of optical fibers is relatively rotated around the optical axis with respect to the other. Are inclined at different angles with respect to a direction perpendicular to the optical axis,
The optical fiber connection structure according to claim 6. A holding tool for holding the pair of optical fibers;
The connection structure of the optical fiber as described in any one of Claims 1-9. The holder is
A substrate having a holding groove for holding the pair of optical fibers;
A lid for sandwiching the pair of optical fibers with the substrate;
A pressing member that presses the lid toward the substrate;
It is considered as a mechanical splice with
The optical fiber connection structure according to claim 10. The holder is
A substrate having a holding groove for holding the pair of optical fibers;
A lid for sandwiching the pair of optical fibers with the substrate;
A pressing member that presses the lid toward the substrate;
One of the pair of optical fibers is built in, and a ferrule supported by the substrate;
It is said to be an on-site optical connector with
The optical fiber connection structure according to claim 10. The end face of the optical fiber built in the ferrule is inclined with respect to a direction perpendicular to the optical axis.
The optical fiber connection structure according to claim 11. The holder is
A first ferrule that holds a plurality of one of the pair of optical fibers arranged in parallel;
Holding the other of the pair of optical fibers in a state of being arranged in parallel, a second ferrule connected to the first ferrule;
MT type connector with
The optical fiber connection structure according to claim 10.

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