JP7055117B2 - Optical fiber end structure and optical connector structure using it - Google Patents

Description

The present invention relates to an optical fiber end structure and an optical connector structure using the same.

There is a mode stripper provided on the outer peripheral surface of the optical fiber as a means for emitting and removing the leaked light (clad mode light) propagating through the clad of the optical fiber to the outside. For example, in Patent Document 1, the optical detection device includes a first optical fiber and a second optical fiber connected to the downstream side thereof, and the first optical fiber is a first core and a first cladding on the outer side thereof. A first mode stripper is provided on the outer peripheral surface of the first clad, and the second optical fiber has a second core, an inner clad on the outer side thereof, a low refractive index layer on the outer side thereof, and an outer clad on the outer side thereof. A structure is disclosed in which a second mode stripper is provided on the outer peripheral surface of the outer clad.

Japanese Unexamined Patent Publication No. 2019-70600

In an optical fiber used in a laser processing machine or the like, there is a risk that the jacket will be burnt out at the end on the incident side due to leakage light that has not been incident on the core due to misalignment or the like. Further, at the end portion on the emission side, there is a possibility that the same jacket may be burnt due to the leakage light of the reflected light from the laser beam irradiation target incident on the clad. Therefore, in order to emit these harmful leaked lights to the outside and remove them, a mode stripper is provided on the outer peripheral surface of the end portion of the optical fiber.

However, in the conventional mode stripper, if the propagation angle of the leaked light with respect to the axial direction is sufficiently larger than the numerical aperture (NA) determined by the refractive index between the core and the clad, excellent leakage light removal efficiency can be obtained. When the propagation angle is slightly larger than the numerical aperture (NA), there is a problem that the removal efficiency of the leaked light is low.

An object of the present invention is to provide an optical fiber end structure capable of obtaining excellent leakage light removal efficiency regardless of the magnitude of the propagation angle of the leakage light in the axial direction.

The present invention has an optical fiber end structure in which a bare fiber protrudes from a portion of an optical fiber provided with a jacket and is exposed. The exposed bare fiber includes a mode stripper provided on an outer peripheral surface and the mode stripper. It has a leaked light emitting surface facing the rear side, which is different from the constituent surface of the above.

The present invention is an optical connector structure in which the optical fiber end structure of the present invention is housed in an optical connector.

According to the present invention, the bare fiber exposed at the end has a leaked light emitting surface facing the rear side different from the constituent surface of the mode stripper in addition to the mode stripper provided on the outer peripheral surface. Excellent efficiency of removing leaked light can be obtained regardless of the magnitude of the propagation angle with respect to the axial direction of.

It is sectional drawing of the optical connector structure which concerns on Embodiment 1. FIG. It is sectional drawing of the modification of the optical connector structure which concerns on Embodiment 1. FIG. It is sectional drawing of the optical connector structure which concerns on Embodiment 2. FIG. It is sectional drawing of the optical connector structure which concerns on Embodiment 3. FIG. It is sectional drawing of the optical connector structure which concerns on Embodiment 4. FIG. It is sectional drawing of the optical connector structure which concerns on Embodiment 5.

Hereinafter, embodiments will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1A shows the optical connector structure C according to the first embodiment. The optical connector structure C according to the first embodiment is an optical fiber end structure of an optical fiber 10 included in an optical fiber cable for laser optical transmission used in a laser processing apparatus such as a laser cutting apparatus, a laser welding apparatus, and a 3D metal printer. A is housed in the optical connector 20 and configured.

The optical fiber 10 has a bare fiber 11 and a jacket 12 covering the bare fiber 11. The outer diameter of the optical fiber 10 is, for example, 1.3 mm.

The bare fiber 11 includes a core 11a having a relatively high refractive index and a clad 11b having a relatively low refractive index covering the core 11a. In the bare fiber 11, for example, the core 11a is formed of non-doped pure quartz, and the clad 11b is formed of quartz doped with a dopant (F, B, etc.) that lowers the refractive index. The bare fiber 11 may be a multi-core fiber having a plurality of cores. Further, the bare fiber 11 may include a support layer of a second clad that further covers the clad 11b.

The jacket 12 may be composed of a single layer made of a fluororesin, an ultraviolet curable resin, a thermosetting resin, or the like, or may be composed of, for example, an inner buffer layer of a silicone resin and a nylon resin or fluorine that covers the inner buffer layer. It may be composed of two layers, that is, the outer coating layer of the resin. The thickness of the jacket 12 is, for example, 400 μm.

In the optical fiber end structure A, the bare fiber 11 protrudes from the portion where the jacket 12 is provided and is exposed. The bare fiber 11 exposed at the end includes a first fiber portion 111 on the distal end side having a different outer diameter and a second fiber portion 112 on the rear side thereof. Here, in the present application, the "tip side" of the bare fiber 11 exposed at the end is referred to as the "tip side" as it is, and the "base end side" is referred to as the "rear side". The first fiber portion 111 is formed to have a relatively large outer diameter. The outer diameter of the first fiber portion 111 is, for example, 500 μm or more and 1000 μm or less. The length of the first fiber portion 111 is, for example, 10 mm or more and 200 mm or less. The second fiber portion 112 is formed to have a relatively small outer diameter, and the outer diameter is the same as the outer diameter of the bare fiber 11 in the portion where the jacket 12 is provided. The outer diameter of the second fiber portion 112 is, for example, 150 μm or more and 400 μm or less. The length of the second fiber portion 112 is, for example, 10 mm or more and 200 mm or less.

The rear end face of the first fiber portion 111 and the end face on the tip end side of the second fiber portion 112 are both vertical planes with respect to the axial direction. The rear end surface of the first fiber portion 111 having a relatively large outer diameter and the end surface of the second fiber portion 112 on the distal end side having a relatively small outer diameter are coaxially abutted and fused and connected. Therefore, at the connection portion between the first fiber portion 111 and the second fiber portion 112, the outer diameter changes discontinuously, so that the rear end surface of the first fiber portion 111 is with the second fiber portion 112. Includes a surface facing the rear side of the ring on the outside of the fused joint. Here, in the present application, the "plane facing the rear side" means a surface in which the angle formed by the normal direction of the surface with respect to the axial direction is 0 ° or more and less than 90 ° toward the rear side.

The first fiber portion 111 and the second fiber portion 112 preferably have the same core diameter, but even when the core diameters are different, the connection loss is preferably 0.5 dB or less, more preferably 0.1 dB or less. More preferably, it may be 0.05 dB or less. The core diameters of the first fiber portion 111 and the second fiber portion 112 are, for example, 10 μm or more and 1000 μm or less.

A first mode stripper 131 is provided on the outer peripheral surface of the first fiber portion 111. Further, a second mode stripper 132 is provided on the outer peripheral surface of the second fiber portion 112. These first and second mode strippers 132 may be provided in the portion of the first fiber portion 111 and / or the second fiber portion 112 having a predetermined length in the length direction, and may be provided over the entire length in the length direction. It may be provided. These first and second mode strippers 132 are, for example, rough surfaces formed by subjecting their outer peripheral surfaces to machining such as polishing, blasting, cutting, wet etching, laser processing, or the like, or It is composed of a rough surface formed by depositing and melting fine particles such as silica.

The optical connector 20 is formed of a metal such as stainless steel in a cylindrical shape. The optical connector 20 is formed with a cylindrical hole having a large inner diameter on the tip side, and an annular sapphire block 21 is internally fitted in the middle portion thereof to form a quartz block accommodating portion 22 on the distal end side and a bare fiber accommodating portion 23 on the rear side. It is partitioned into. The quartz block accommodating portion 22 accommodates the massive quartz block 24. An optical fiber insertion hole 25 having an inner diameter substantially the same as the outer diameter of the optical fiber 10 is continuously formed on the rear side of the bare fiber accommodating portion 23.

The optical fiber end structure A is housed in the optical connector 20 by inserting the optical fiber 10 from the rear side of the optical connector 20. In the optical fiber end structure A, the portion provided with the jacket 12 is internally fitted and held in the optical fiber insertion hole 25, and the tip surface thereof is positioned at the tip of the optical fiber insertion hole 25. The exposed bare fiber 11 including the first fiber portion 111 and the second fiber portion 112 extends axially in the space in the bare fiber accommodating portion 23 in a non-contact manner, and the tip portion thereof is internally fitted and held in the sapphire block 21. And the tip surface is fused and connected to the quartz block 24.

In the optical connector structure C according to the first embodiment, in the case of the optical connector 20 on the incident side, the laser light from the light source and in the case of the optical connector 20 on the exit side, the reflected light from the irradiated object is quartz. It also enters the clad 11b of the first fiber portion 111 via the block 24 and propagates as leaked light. At this time, most of the components of the leaked light whose propagation angle with respect to the axial direction is sufficiently larger than the numerical aperture (NA) of the first fiber portion 111 are provided on the outer peripheral surface of the first fiber portion 111. It is discharged from the one-mode stripper 131 into the space inside the bare fiber accommodating portion 23 and removed.

On the other hand, the component of the leaked light whose propagation angle with respect to the axial direction is slightly larger than the numerical aperture (NA) of the first fiber portion 111 is not sufficiently removed by the first mode stripper 131. It is presumed that this is because the difference between the core diameter and the outer diameter of the first fiber portion 111 is large, and it becomes difficult for the leaked light of this component to reach the first mode stripper 131. However, the leaked light of this component is the bare fiber accommodating portion 23 external from the surface facing the rear side of the outer annular portion of the portion fused and connected to the second fiber portion 112 on the rear end surface of the first fiber portion 111. It is released into the inner space and removed. Therefore, the surface of the end surface on the rear side of the first fiber portion 111 facing the rear side of the annular shape is a rear side different from the constituent surface of the first mode stripper 131 provided on the rear side of the first mode stripper 131. It constitutes a leaked light emitting surface 14 facing the surface. The leaked light emitting surface 14 may be a smooth surface or a rough surface. As a measure to remove the leaked light of this component, it is conceivable to reduce the outer diameter of the exposed bare fiber to reduce the difference between the core diameter and the outer diameter of the bare fiber. There is a concern that the resistance of the bare fiber to the laser will be low, and since it is necessary to handle the bare fiber having a small diameter, there will be a problem that the manufacturing process will be complicated.

Further, the leaked light not removed from the first mode stripper 131 and the leaked light emitting surface 14 is incident on the clad 11b of the second fiber portion 112 and propagates, and is provided on the outer peripheral surface of the second fiber portion 112. It is discharged from the two-mode stripper 132 into the space inside the bare fiber accommodating portion 23 and removed. The second mode stripper 132 is not always necessary as long as the leaked light can be sufficiently removed from the first mode stripper 131 and the leaked light emitting surface 14.

The leaked light emitted from the first mode stripper 131 and the leaked light emitting surface 14 of the first fiber portion 111 and the second mode stripper 132 of the second fiber portion 112 into the space inside the bare fiber accommodating portion 23 is the optical connector 20. The inner wall of the bare fiber accommodating portion 23 is irradiated, absorbed and converted into heat energy, which is conducted through the optical connector 20 and radiated to the outside.

According to the above configuration, the first fiber portion 111 of the bare fiber 11 exposed at the end thereof, in addition to the first mode stripper 131 provided on the outer peripheral surface thereof, has a rear side different from the constituent surface of the mode stripper. By having the leaked light emitting surface 14 facing, the component whose propagation angle with respect to the axial direction of the leaked light is sufficiently larger than the number of openings (NA) of the first fiber portion 111 is effectively removed from the first mode stripper 131. At the same time, a component of the leaked light not removed by the first mode stripper 131 whose propagation angle with respect to the axial direction is slightly larger than the number of openings (NA) of the first fiber portion 111 is discharged from the leaked light emitting surface 14. Since it is removed, excellent leakage light removal efficiency can be obtained regardless of the magnitude of the propagation angle of the leaked light with respect to the axial direction. Further, since the second fiber portion 112 of the bare fiber 11 has the second mode stripper 132 provided on the outer peripheral surface thereof, it is not removed by the first mode stripper 131 and the leaked light emitting surface 14 of the first fiber portion 111. The leaked light can be removed from the second mode stripper 132. As a result, it is possible to suppress the burning of the jacket 12 due to the harmful leaked light.

By the way, with the miniaturization of laser processing equipment, the processing field is expanding, and there is a demand for easy handling in the field of optical fiber cables and repair in the event of a failure. The diameter is becoming smaller. However, when the diameter of the optical fiber is reduced, there is a concern that the resistance to the leaked light will be lowered. However, according to the above configuration, the leaked light can be efficiently removed from the first mode stripper 131 and the leaked light emitting surface 14 of the first fiber portion 111 having a large outer diameter, so that the second fiber portion 112 and the leaked light emitting surface 14 can be efficiently removed. It is not necessary to worry about the resistance to the leakage light of the portion provided with the jacket 12 that follows it, and the diameter of the optical fiber 10 can be reduced. In addition, if the optical connector 20 having the quartz block 24 to which the first fiber portion 111 is fused and connected is modularized, the outer diameter of the optical fiber 10 can be freely selected and fused and connected to the first fiber portion 111. This makes it possible to obtain an optical fiber cable in which the desired optical fiber 10 has a reduced diameter.

As shown in FIG. 1B, in the optical connector structure C, the bare fiber accommodating portion 23 is filled with the heat conductive material 26 so that the rear portion of the first fiber portion 111 and the second fiber portion 112 are embedded. May be good. In this case, the leaked light emitting surface 14 of the first fiber portion 111 and the second mode stripper 132 of the second fiber portion 112 are embedded in the heat conductive material 26. As a result, the heat generated by the leaked light emitting surface 14 of the first fiber portion 111 and the second mode stripper 132 of the second fiber portion 112 is efficiently conducted to the optical connector 20 via the heat conductive material 26 and dissipated. Can be made to. The first mode stripper 131 of the first fiber portion 111 may also be embedded in the heat conductive material 26. Further, cooling water may be circulated in the optical connector 20 to be positively cooled by water cooling.

(Embodiment 2)
FIG. 2 shows the optical connector structure C according to the second embodiment. The parts having the same names as those in the first embodiment are indicated by the same reference numerals.

In the optical connector structure C according to the second embodiment, in the optical fiber end structure A, the outer peripheral portion of the rear end of the first fiber portion 111 is convex outward so as to be smoothly continuous from the outer peripheral surface to the rear end surface. It is formed on the curved surface of. This curved surface also constitutes the leaked light emitting surface 14 facing the rear side.

According to the above configuration, on the curved surface of the outer peripheral portion of the rear end of the first fiber portion 111 constituting the leaked light emitting surface 14, in addition to the large emission area of the leaked light, it is located on the rear end side of the first fiber portion 111. Since the inclination angle with respect to the axial direction changes continuously as it goes, the critical angle for a large amount of leaked light becomes smaller, and the leaked light can be removed more efficiently. Further, since the reflected light returning from the leaked light emitting surface 14 to the tip direction is reduced by adopting this shape, it is possible to reduce the adverse effect of the light returning to the light source or the processing head of the laser processing machine. Other configurations and actions and effects are the same as those in the first embodiment.

(Embodiment 3)
FIG. 3 shows the optical connector structure C according to the third embodiment. The parts having the same names as those in the first embodiment are indicated by the same reference numerals.

In the optical connector structure C according to the third embodiment, in the optical fiber end structure A, the first fiber portion 111 and the second fiber portion 112 basically have the same outer diameter, but the second fiber portion 112 has the same outer diameter. Only the portion on the tip side is formed in a tapered shape in which the outer diameter is gradually and continuously reduced toward the tip side. The end face on the rear side of the first fiber portion 111 having a relatively large outer diameter is coaxially abutted against the end face on the tip side of the second fiber portion 112 having a reduced outer diameter and fused. It is connected. Therefore, the outer diameter of the connection portion between the first fiber portion 111 and the second fiber portion 112 changes discontinuously, so that the rear end surface of the first fiber portion 111 is different from the second fiber portion 112. A surface facing the rear side of the ring is included on the outside of the fusion-bonded portion, and this constitutes the leakage light emission surface 14. The length of the tapered portion of the second fiber portion 112 is, for example, 1 mm or more and 100 mm or less. The outer diameter of the end face on the distal end side of the second fiber portion 112 is, for example, 150 μm or more and 400 μm or less. The outer diameter of the portion on the tip end side of the second fiber portion 112 may be reduced in steps toward the tip end side.

According to the above configuration, since the outer diameters of the first fiber portion 111 and the second fiber portion 112 are the same, an optical fiber 10 having the same specifications can be used for them. In that case, the first fiber portion 111 and the second fiber portion 112 and Since the core diameters of the second fiber portions 112 are the same, the connection loss thereof can be suppressed low. Other configurations and actions and effects are the same as those in the first embodiment.

As in the second embodiment, the outer peripheral portion of the rear end of the first fiber portion 111 is formed on an outwardly convex curved surface so as to be smoothly continuous from the outer peripheral surface to the end surface on the rear side, and leakage light is emitted. The surface 14 may be configured. Further, the portion on the rear side of the first fiber portion 111 is formed in a tapered shape in which the outer diameter is gradually and continuously reduced toward the rear side as in the fourth embodiment described later, and constitutes the leaked light emitting surface 14. You may be doing it. With these shapes, the reflected light returning from the leaked light emitting surface 14 toward the tip end is reduced, so that the adverse effect of the light returning to the light source or the processing head of the laser processing machine can be reduced.

(Embodiment 4)
FIG. 4 shows the optical connector structure C according to the fourth embodiment. The parts having the same names as those in the first embodiment are indicated by the same reference numerals.

In the optical connector structure C according to the fourth embodiment, in the optical fiber end structure A, the rear portion of the first fiber portion 111 is formed in a tapered shape in which the outer diameter is gradually and continuously reduced toward the rear side. Has been done. The length of the tapered portion of the first fiber portion 111 is, for example, 1 mm or more and 100 mm or less. The outer diameter of the end face on the rear side of the first fiber portion 111 is larger than the outer diameter of the end face on the distal end side of the second fiber portion 112, and the difference in the outer diameter is, for example, 10 μm or more and 1000 μm or less. The end face on the rear side of the first fiber portion 111 having a relatively large outer diameter is coaxially abutted against the end face on the tip side of the second fiber portion 112 having a relatively small outer diameter and is fused and connected. Therefore, the outer diameter of the connection portion between the first fiber portion 111 and the second fiber portion 112 changes discontinuously, so that the rear end surface of the first fiber portion 111 is different from the second fiber portion 112. A surface facing the rear side of the ring is included on the outside of the fusion-bonded portion, and this constitutes the leakage light emission surface 14. In addition, the outer peripheral surface of the portion of the first fiber portion 111 whose outer diameter is gradually and continuously reduced toward the rear side to be formed in a tapered shape is also different from the constituent surface of the first mode stripper 131. It constitutes a leaked light emitting surface 14 facing the rear side of the above.

The outer diameter of the rear end surface of the first fiber portion 111 is the same as the outer diameter of the end surface on the distal end side of the second fiber portion 112, and the rear end surface of the first fiber portion 111 is leaked light. The configuration may not have the emission surface 14. Further, the outer diameter of the portion on the rear side of the first fiber portion 111 may be reduced in a stepped manner toward the rear side. Further, as in the second embodiment, the rear end outer peripheral portion of the first fiber portion 111 is formed on an outwardly convex curved surface so as to be smoothly continuous from the outer peripheral surface to the rear end surface, and the leaked light emitting surface 14 is formed. May be configured.

According to the above configuration, in the tapered portion of the first fiber portion 111 constituting the leaked light emitting surface 14, the leaked light emission area is large and the leaked light is inclined with respect to the axial direction. Therefore, the critical angle for a large amount of leaked light becomes small, and the leaked light can be removed more efficiently. Further, since the reflected light returning from the leaked light emitting surface 14 to the tip direction is reduced by adopting this shape, it is possible to reduce the adverse effect of the light returning to the light source or the processing head of the laser processing machine. Other configurations and actions and effects are the same as those in the first embodiment.

(Embodiment 5)
FIG. 5 shows the optical connector structure C according to the fifth embodiment. The parts having the same names as those in the first embodiment are indicated by the same reference numerals.

In the optical connector structure C according to the fifth embodiment, in the optical fiber end structure A, the first fiber portion 111 and the second fiber portion 112 basically have the same outer diameter, but the first fiber portion 111 has the same outer diameter. Only the portion on the rear side is formed in a tapered shape in which the outer diameter is gradually reduced toward the rear side. The length of the tapered portion of the first fiber portion 111 is, for example, 1 mm or more and 100 mm or less. The outer diameter of the end face on the rear side of the first fiber portion 111 is smaller than the outer diameter of the end face on the distal end side of the second fiber portion 112, and the difference in the outer diameter is, for example, 10 μm or more and 1000 μm or less. The end face on the rear side of the first fiber portion 111, which has a relatively small outer diameter, is coaxially abutted against the end face on the front end side, which has a relatively large outer diameter of the second fiber portion 112, and is fused and connected. The outer peripheral surface of the portion of the first fiber portion 111 whose outer diameter is gradually and continuously reduced toward the rear side to form a taper faces the rear side different from the constituent surface of the first mode stripper 131. It constitutes the leaked light emitting surface 14. The outer diameter of the rear portion of the first fiber portion 111 may be reduced in steps toward the rear side.

According to the above configuration, in the tapered portion of the first fiber portion 111 constituting the leaked light emitting surface 14, the leaked light emission area is large and the leaked light is inclined with respect to the axial direction. Therefore, the critical angle for a large amount of leaked light becomes small, and the leaked light can be removed more efficiently. Further, since the reflected light returning from the leaked light emitting surface 14 to the tip direction is reduced by adopting this shape, it is possible to reduce the adverse effect of the light returning to the light source or the processing head of the laser processing machine. Further, since the outer diameters of the first fiber portion 111 and the second fiber portion 112 are the same, an optical fiber 10 having the same specifications can be used for them. In that case, the first fiber portion 111 and the second fiber portion 112 can be used. Since the core diameters of the two are the same, the connection loss between them can be suppressed to a low level. Other configurations and actions and effects are the same as those in the first embodiment.

(Other embodiments)
In the above embodiments 1 to 5, the exposed bare fiber 11 is configured such that the first fiber portion 111 and the second fiber portion 112 are fused and connected, but the present invention is not particularly limited to this, and the connection portion is not particularly limited. A mode stripper and a leaked light emitting surface may be formed and processed on the outer peripheral surface of the bare fiber.

In the above embodiments 1 to 5, the exposed bare fiber 11 is configured such that the first fiber portion 111 and the second fiber portion 112 are fused and connected, but the present invention is not particularly limited to this, and the first A configuration in which the third fiber portion is provided at one or more of the tip side of the fiber portion 111, between the first fiber portion 111 and the second fiber portion 112, and the rear side of the second fiber portion 112. May be.

In the above embodiments 1 to 5, the leaked light emitting surface 14 is provided on the rear side of the first mode stripper 131, but the present invention is not particularly limited to this, and the leaked light is emitted on the tip side of the mode stripper. It may be configured with a surface.

The present invention is useful in the technical field of an optical fiber end structure and an optical connector structure using the same.

A Optical fiber end structure C Optical connector structure 10 Optical fiber 11 Bare fiber 11a Core 11b Clad 111 First fiber part 112 Second fiber part 12 Jacket 131 First mode stripper 132 Second mode stripper 14 Leakage light emission surface 20 Optical connector 21 Sapphire block 22 Quartz block accommodating part 23 Fiber accommodating part 24 Quartz block 25 Optical fiber insertion hole 26 Thermal conductive material

Claims (6)

An optical fiber end structure in which a bare fiber protrudes from a portion of the optical fiber provided with a jacket and is exposed.
The exposed bare fiber is a first fiber portion having a mode stripper provided on the outer peripheral surface and a first fiber portion having a relatively large outer diameter on the distal end side having a leakage light emitting surface facing the rear side different from the constituent surface of the mode stripper. And a second fiber portion having a second mode stripper provided on the outer peripheral surface and having a relatively small outer diameter on the rear side.
The rear end face of the first fiber portion having a relatively large outer diameter and the end face of the tip side having a relatively small outer diameter of the second fiber portion are connected to each other, and the rear side of the first fiber portion is connected. The surface of the end surface facing the rear side outside the portion connected to the second fiber portion constitutes the leaked light emitting surface.
The outer peripheral portion of the rear end of the first fiber portion is formed on an outwardly convex curved surface so as to smoothly continue from the outer peripheral surface to the end surface on the rear side, and the curved surface constitutes the leaked light emitting surface. Optical fiber end structure. In the optical fiber end structure according to claim 1 ,
The rear portion of the first fiber portion is formed so that the outer diameter is reduced toward the rear side, and the outer circumference of the portion formed so that the outer diameter is reduced toward the rear side. An optical fiber end structure in which a surface constitutes the leaked light emitting surface. An optical fiber end structure in which a bare fiber protrudes from a portion of the optical fiber provided with a jacket and is exposed.
The exposed bare fiber has a mode stripper provided on the outer peripheral surface and a leaked light emitting surface facing the rear side different from the constituent surface of the mode stripper.
The exposed bare fiber includes a first fiber portion on the distal end side having the mode stripper and the leaked light emitting surface, and a second fiber portion on the rear side.
The outer peripheral portion of the rear end of the first fiber portion is formed on an outwardly convex curved surface so as to smoothly continue from the outer peripheral surface to the end surface on the rear side, and the curved surface constitutes the leaked light emitting surface. Optical fiber end structure. An optical fiber end structure in which a bare fiber protrudes from a portion of the optical fiber provided with a jacket and is exposed.
The exposed bare fiber has a mode stripper provided on the outer peripheral surface and a leaked light emitting surface facing the rear side different from the constituent surface of the mode stripper.
The exposed bare fiber includes a first fiber portion on the distal end side having the mode stripper and the leaked light emitting surface, and a second fiber portion on the rear side.
The tip side portion of the second fiber portion is formed so that the outer diameter decreases toward the tip side, and the tip end surface of the second fiber portion having a relatively small outer diameter is described above. It is connected to the rear end surface of the first fiber portion having a relatively large outer diameter, and faces the outer rear side of the portion connected to the second fiber portion on the rear end surface of the first fiber portion. The surface constitutes the leaked light emitting surface, and the surface constitutes the leaked light emitting surface .
The first fiber portion and the second fiber portion are configured by using optical fibers having the same specifications.
The outer diameter of the tip end side portion of the second fiber portion is an optical fiber end portion structure that starts from the same outer diameter as the first fiber portion and is reduced in diameter toward the tip end side . An optical fiber end structure in which a bare fiber protrudes from a portion of the optical fiber provided with a jacket and is exposed.
The exposed bare fiber has a mode stripper provided on the outer peripheral surface and a leaked light emitting surface facing the rear side different from the constituent surface of the mode stripper.
The exposed bare fiber includes a first fiber portion on the distal end side having the mode stripper and the leaked light emitting surface, and a second fiber portion on the rear side.
The rear portion of the first fiber portion is formed so that the outer diameter is reduced toward the rear side, and the rear end surface of the first fiber portion having a relatively small outer diameter is the said. The second fiber portion is connected to the end surface on the distal end side having a relatively large outer diameter, and the outer peripheral surface of the rear portion of the first fiber portion constitutes the leaked light emitting surface.
The first fiber portion and the second fiber portion are configured by using optical fibers having the same specifications.
The outer diameter of the rear portion of the first fiber portion is an optical fiber end structure that starts from the same outer diameter as the second fiber portion and is reduced in diameter toward the rear side. An optical connector structure in which the optical fiber end structure according to any one of claims 1 to 5 is housed in an optical connector.

Images