JP6903696B2 - Clad mode stripper structure - Google Patents

Description

The present invention relates to a clad mode stripper structure.

In an optical fiber used in a laser processing machine or the like, on the incident side, a part of the laser light from the laser light source is incident on the clad without being incident on the core. Further, on the emitting side, the reflected light from the work to be irradiated with the laser beam is incident on the clad. Then, the jacket of the optical fiber may be burnt out by the clad mode light incident on the clad. Therefore, a clad mode stripper structure for radiating and removing clad mode light to the outside is configured by providing a groove along the length direction on the outer peripheral surface of the clad exposed by peeling off the jacket at the end of the optical fiber. (For example, Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 2017-223897 JP-A-2017-187523

By the way, in the clad mode stripper structure composed of grooves having a uniform depth, the intensity of the clad mode light radiated to the outside and removed decreases exponentially from the tip side to the base end side, so that the tip At the side end, a hot spot where the intensity of the clad mode light emitted and removed peaks is generated, which may cause the optical fiber to melt. On the other hand, since the clad mode stripper structure needs to be arranged in the optical connector, its length is limited, and it is preferable that the clad mode stripper structure is short.

An object of the present invention is to provide a clad mode stripper structure capable of suppressing the generation of hot spots of clad mode light and sufficiently removing clad mode light even with a short length.

The present invention is a clad mode stripper structure in which a groove is provided along the length direction on the outer peripheral surface of the clad at the end of the optical fiber, and the depth of the groove is from the tip side to the base end side. The tip side portion that becomes deeper as it goes, and the proximal end side portion in which the depth of the groove is equal to or less than the maximum value of the groove depth of the distal end side portion, and the proximal end side portion includes the groove. The depth of the groove becomes shallower from the distal end side to the proximal end side, and the absolute value of the decreasing gradient of the depth of the groove from the distal end side to the proximal end side in the proximal end side portion is the absolute value of the distal end side portion. It is smaller than the absolute value of the increasing gradient of the depth of the groove from the tip end side to the base end side .

According to the present invention, in the distal end side portion, the groove depth becomes deeper from the distal end side to the proximal end side, and in the proximal end side portion, the groove depth is the groove depth of the distal end side portion. When the value is not more than the maximum value of, the generation of hot spots of the clad mode light can be suppressed, and the clad mode light can be sufficiently removed even with a short length.

It is a perspective view of the end part of the optical fiber which has the clad mode stripper structure which concerns on Embodiment 1. FIG. FIG. 5 is a vertical cross-sectional view of an end portion of an optical fiber having a clad mode stripper structure according to the first embodiment. It is a figure which shows the depth of the groove along the length direction of the 1st aspect of the clad mode stripper structure which concerns on Embodiment 1. FIG. It is a figure which shows the depth of the groove along the length direction of the 2nd aspect of the clad mode stripper structure which concerns on Embodiment 1. FIG. It is a vertical sectional view of the optical connector structure which attached the optical connector to the optical fiber which has the clad mode stripper structure which concerns on Embodiment 1. FIG. It is a figure which shows the processing method of the workpiece by the laser processing machine. It is a figure which shows the intensity of the clad mode light which is radiated to the outside along the length direction of the clad mode stripper structure which is composed of the groove of a uniform depth over the whole, and is removed. It is a figure which shows the intensity of the clad mode light which is radiated to the outside along the length direction of the clad mode stripper structure which concerns on Embodiment 1, and is removed. It is a vertical sectional view of the end part of the optical fiber which has the clad mode stripper structure which concerns on Embodiment 2. FIG. It is a figure which shows the depth of the groove along the length direction of the 1st aspect of the clad mode stripper structure which concerns on Embodiment 2. FIG. It is a figure which shows the depth of the groove along the length direction of the 2nd aspect of the clad mode stripper structure which concerns on Embodiment 2. FIG. It is a figure which shows the intensity of the clad mode light which is radiated to the outside along the length direction of the clad mode stripper structure which concerns on Embodiment 2, and is removed. It is a perspective view of the end part of the optical fiber which has the clad mode stripper structure which concerns on Embodiment 1. FIG. FIG. 5 is a vertical cross-sectional view of a first aspect of an end portion of an optical fiber having a clad mode stripper structure according to a third embodiment. FIG. 5 is a vertical cross-sectional view of a second aspect of an end portion of an optical fiber having a clad mode stripper structure according to a third embodiment.

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

(Embodiment 1)
1A and 1B show an optical fiber 10 having a clad mode stripper structure M according to the first embodiment. The optical fiber 10 is used as a laser light transmission member of an optical fiber cable mounted on a laser processing machine or the like that performs cutting or welding, for example.

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

The bare optical fiber 11 has a core 111 having a relatively high refractive index and a clad 112 having a relatively low refractive index covering the core 111. In the bare optical fiber 11, for example, the core 111 is formed of non-doped pure quartz, and the clad 112 is formed of quartz doped with a dopant (F, B, etc.) that lowers the refractive index. The outer diameter of the bare optical fiber 11 is, for example, 500 μm. The diameter of the core 111 is, for example, 100 μm. The bare optical fiber 11 may be a multi-core optical fiber having a plurality of cores.

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

In the optical fiber 10, the jacket 12 is peeled off at each end of one and the other, and the bare optical fiber 11 is projected and exposed. Then, the clad mode stripper structure M according to the first embodiment for radiating and removing the clad mode light to the outside is provided on the outer peripheral surface of the clad 112 of the bare optical fiber 11 exposed at the end of the optical fiber 10. ing. The length of the clad mode stripper structure M is, for example, 20 mm or more and 50 mm or less.

The clad mode stripper structure M according to the first embodiment is configured by providing a groove 13 along the length direction on the outer peripheral surface of the clad 112 in the bare optical fiber 11 exposed at the end of the optical fiber 10. The groove 13 is formed so as to spirally extend along the length direction on the outer peripheral surface of the clad 112 in the bare optical fiber 11 exposed at the end of the optical fiber 10. The cross-sectional shape of the groove 13 may be a U-shape, a V-shape, a trapezoidal shape, or the like, in addition to the U-shape.

The clad mode stripper structure M according to the first embodiment includes a distal end side portion M ₁ and a proximal end side portion M ₂ on the proximal end side thereof. The groove 13 is formed so as to extend between the _{distal end side portion M 1} and the proximal end side portion M _2. Then, in the tip end side portion M ₁ , the depth of the groove 13 becomes deeper from the tip end side to the base end side. In the proximal end side portion M ₂ , the depth of the groove 13 is equal to or less than the maximum value of the depth of the groove 13 in the distal end side portion M _{1 and is uniform.} The "depth of the groove 13" in the present application is the distance from the outer peripheral surface of the clad 112 to the deepest portion of the groove 13.

Cladding mode stripper structure M according to the first embodiment, the depth of the distal portion M ₁ of the groove 13, as shown by the solid line in FIG. 2A, have continuously deepened toward the proximal side from the distal end Also, as shown by a solid line in FIG. 2B, the depth may be gradually increased from the tip end side to the base end side.

When the depth of the groove 13 is deep, the fume generated during the forming process adheres to the surface to form an uneven surface in the groove 13 and its periphery, and when the clad mode light is radiated and removed, the groove 13 is formed. Since heat generation becomes remarkable, _{the maximum depth of the groove 13 of the distal end side portion M 1} is smaller than the thickness of the clad 112, preferably 0.1 mm or less, and more preferably 0.06 mm or less.

The width of the opening of the groove 13 of the tip end side portion M ₁ may be non-uniform, but is preferably uniform from the viewpoint of ease of processing of the groove 13. The width of the opening of the groove 13 of the tip end side portion M ₁ is, for example, 0.02 mm or more and 1 mm or less. The spiral pitch of the groove 13 of the tip end side portion M ₁ may be non-uniform, but is preferably uniform from the viewpoint of ease of processing of the groove 13. The spiral pitch of the groove 13 of the tip end side portion M ₁ is, for example, 0.05 mm or more and 5 mm or less. The length of the tip side portion M ₁ is, for example, 10 mm or more and 40 mm or less.

The depth of the groove 13 of the proximal end side portion M ₂ may be a constant value equal to or less than the maximum value of the depth of the groove 13 of _{the distal end side portion M 1, but from the viewpoint of enhancing the clad mode light removal performance, the tip end} It is preferably 70% or more, more preferably 90% or more of the maximum depth of the groove 13 of the side portion M _{1 , and as shown by the solid line in FIGS. 2A and 2B, the tip side portion M 1} it is continuous with the depth of the groove 13 of the end of the proximal, that is, it is more preferably the same as the maximum value of the depth of the distal portion M ₁ of the groove 13. The depth of the groove 13 of the proximal end side portion M ₂ is, for example, 0.01 mm or more and 0.1 mm or less.

The width of the opening of the groove 13 of the base end side portion M ₂ may be non-uniform, but is preferably uniform from the viewpoint of ease of processing of the groove 13. The width of the opening of the groove 13 of the proximal end side portion M _{2 may be different from the width of the opening of the groove 13 of the distal end side portion M 1} , but from the viewpoint of ease of processing of the groove 13, the distal end side portion M ₁ It is preferable that the width of the opening of the groove 13 is the same as that of the groove 13. The width of the opening of the groove 13 of the proximal end side portion M ₂ is, for example, 0.02 mm or more and 1 mm or less.

The spiral pitch of the groove 13 of the proximal end side portion M ₂ may be non-uniform, but is preferably uniform from the viewpoint of ease of processing of the groove 13. The spiral pitch of the groove 13 of the proximal end side portion M _{2 may be different from the spiral pitch of the groove 13 of the distal end side portion M 1} , but from the viewpoint of ease of processing of the groove 13, the groove of the distal end side portion M ₁ It is preferably the same as the spiral pitch of 13. The spiral pitch of the groove 13 of the proximal end side portion M ₂ is, for example, 0.05 mm or more and 5 mm or less.

The length of the proximal end side portion M ₂ is preferably shorter than the length of the distal end side portion M _1. The length of the proximal end side portion M ₂ is, for example, 5 mm or more and 35 mm or less.

The clad mode stripper structure M according to the first embodiment of the above configuration is obtained by irradiating the outer peripheral surface of the clad 112 at the end of the optical fiber 10 with _{a laser beam from, for example, a CO 2} laser to form a groove 13. be able to. At this time, the depth of the groove 13 can be controlled by the intensity of the laser beam, the irradiation time, and the like.

FIG. 3 shows an optical connector structure C in which an optical connector 20 is attached to an optical fiber 10. The optical connector structure C is formed at each end of an optical fiber cable mounted on a laser processing machine or the like on the incident side and the sending side.

The optical connector 20 has a connector body 21 which is a tubular member. Inside the connector main body 21, a bare fiber accommodating portion 21a having a large inner diameter formed so as to extend in the length direction is provided in the middle portion thereof, and is continuously rearward of the bare fiber accommodating portion 21a in the length direction. A coated fiber fitting portion 21b having an inner diameter smaller than that of the bare fiber accommodating portion 21a formed so as to extend is provided. Further, a block accommodating portion 21c having an inner diameter intermediate between the bare fiber accommodating portion 21a and the coated fiber fitting portion 21b formed so as to extend in the length direction is provided continuously on the tip side of the bare fiber accommodating portion 21a. .. An annular sealing member 22 is internally fitted at the tip of the bare fiber accommodating portion 21a. A cylindrical fiber holding member 23 is internally fitted in the opening of the sealing member 22. The quartz block 24 is housed in the block housing section 21c.

In the optical connector structure C, a portion having a predetermined length from the tip including the end portion of the optical fiber 10 provided with the clad mode stripper structure M is inserted from the rear of the optical connector 20. Then, the tip of the bare optical fiber 11 is internally fitted and held in the fiber holding member 23, and the end of the bare optical fiber 11 provided with the clad mode stripper structure M according to the first embodiment is the bare fiber accommodating portion. A portion extending 21a in the length direction and being covered with the jacket 12 is internally fitted and held in the coated fiber fitting portion 21b. The end face of the jacket 12 in the portion covered with the jacket 12 is positioned so as to be exposed to the bare fiber accommodating portion 21a. Further, the tip of the bare optical fiber 11 held by the fiber holding member 23 is fused and connected to the quartz block 24 housed in the block accommodating portion 21c.

FIG. 4 shows a processing method of the work W to be irradiated with the laser beam by the laser processing machine 30.

The laser processing machine 30 has a laser light source 31 and an optical fiber cable 32 mounted so as to extend from the laser light source 31 to the work W. The optical fiber cable 32 includes an optical fiber 10 for laser light transmission, and has an optical connector structure C at each end on the incident side and the sending side.

In the processing of the work W by the laser processing machine 30, when the laser light from the laser light source 31 is incident through the quartz block 24 in the optical connector structure C on the incident side, the laser light is mainly the core of the bare optical fiber 11. Although it is incident on the 111 and propagates, a part of the light is leaked light that is not incident on the core 111 due to misalignment or the like and is incident on the clad 112, which is propagated as the clad mode light. Further, in the optical connector structure C on the exit side, the laser light propagating through the core 111 of the bare optical fiber 11 is emitted through the quartz block 24, and the laser light is mainly used for processing the work W. Part of the light is reflected from the work W and enters the clad 112, which propagates as clad mode light. In particular, the laser light having a wavelength in the 1 μm band has a high reflectance to the work W of gold or copper, so that the reflected light also increases. Then, these clad mode lights are input in the clad mode stripper structure M according to the first embodiment arranged in the optical connector 20 in each optical connector structure C in the forward direction from the tip side and radiated to the outside to be removed. Will be done.

Here, in the case of a clad mode stripper structure composed of grooves having a uniform depth throughout, as shown by a solid line in FIG. 5, the intensity of the clad mode light radiated to the outside and removed is from the tip side. Since it decreases exponentially toward the base end side, a hot spot at the tip end side where the intensity of the clad mode light emitted and removed peaks is generated.

However, the cladding mode stripper structure M according to the embodiment 1, as shown by the solid line in FIG. 6, the distal portion M _1, since the depth of the groove 13 is deeper toward the proximal side from the distal end , The intensity of the clad mode light emitted and removed is dispersed as a whole. The depth of the groove 13 in the maximum value or less and is uniform proximal portion M ₂ of the depth of the groove 13 of the distal portion M _1, the strength that was not removed by the distal portion M ₁ The reduced clad mode light is efficiently emitted and removed. From these facts, according to the clad mode stripper structure M according to the first embodiment, the generation of hot spots of clad mode light can be suppressed, and the clad mode light can be sufficiently removed even with a short length. ..

Even in the case of a clad mode stripper structure in which the depth of the groove becomes deeper with a gentle gradient from the tip side to the base end side over the entire surface, it is possible to suppress the generation of hot spots of clad mode light. .. However, in this case, although the clad mode stripper structure needs to be long in order to sufficiently remove the clad mode light, the clad mode stripper structure arranged in the optical connector has a limited length.

Further, even in the case of the clad mode stripper structure in which the depth of the groove becomes steeper and deeper from the tip side to the base end side over the entire surface, it is possible to suppress the generation of hot spots of clad mode light. Moreover, the clad mode light can be sufficiently removed in the clad mode stripper structure having a limited length. However, in this case, the intensity of the clad mode light emitted and removed is increased as a whole, and the depth of the groove is deepened in the portion on the proximal end side, so that the fume generated during the forming process is formed on the surface. When it adheres to form an uneven surface in the groove and its periphery and is removed by radiating clad mode light, heat generation in that portion becomes remarkable.

The clad mode light radiated to the outside and removed in the clad mode stripper structure M according to the first embodiment is absorbed by the connector main body 21 through the inner wall of the bare fiber accommodating portion 21a and converted into heat, and is converted into heat by air cooling or water cooling. Be removed.

(Embodiment 2)
FIG. 7 shows an optical fiber 10 having a clad mode stripper structure M according to the second embodiment. The portion having the same name as that of the first embodiment is indicated by the same reference numeral as that of the first embodiment.

_{In the proximal end side portion M 2} of the clad mode stripper structure M according to the second embodiment, the depth of the groove 13 is equal to or less than the maximum value of the depth of the groove 13 of the distal end side portion M _{1 and from the distal end side to the proximal end side.} It becomes shallower as it goes. In the clad mode stripper structure M _{, as shown in FIG. 8A, the depth of the groove 13 of the proximal end side portion M 2} may be continuously shallower from the distal end side to the proximal end side, as shown in FIG. 8B. As shown, it may become shallower gradually from the tip end side to the base end side. Note that in FIG. 8A and B, the depth of the distal portion M ₁ of the groove 13 respectively show if it is a case where continuously deeper in the solid line and stepwise deep in broken lines. Other configurations are the same as those in the first embodiment.

In the clad mode stripper structure M according to the second embodiment, clad mode light is input in the forward direction from the tip side and radiated to the outside to be removed. However, for example, the clad mode light incident on the clad 112 with low NA may remain without being removed by the clad mode stripper structure M, and such remaining clad mode light propagates through the clad 112 as it is. .. Therefore, the clad mode light in the forward direction from the laser light source is input to the clad mode stripper structure M on the incident side, and the clad mode stripper structure M on the exit side of the reflected light of the work W remains without being removed. Clad mode light in the opposite direction is input. Similarly, the clad mode light in the forward direction of the reflected light of the work W is input to the clad mode stripper structure M on the exit side, and is removed by the clad mode stripper structure M on the incident side of the laser light from the laser light source. The clad mode light in the opposite direction that remains without being input is input.

For cladding mode light to be input in the forward direction to the cladding mode stripper structure M according to the second embodiment, as shown by the solid line in FIG. 9, the distal portion M _1, the proximal end from the distal end side depth of the grooves 13 As it gets deeper towards the side, the intensity of the clad mode light that is radiated and removed is dispersed as a whole. _{Further, in the proximal end side portion M 2} in which the depth of the groove 13 is equal to or less than the maximum value of the depth of the groove 13 of the distal end side portion M ₁ and becomes shallower from the distal end side toward the proximal end side, the distal end side It reduced cladding mode light intensity which has not been removed in part M ₁ is removed by effectively radiation. From these facts, according to the clad mode stripper structure M according to the second embodiment, it is possible to suppress the generation of hot spots of the clad mode light in the forward direction, and sufficiently remove the clad mode light even with a short length. be able to.

Here, when the clad mode light input in the opposite direction has a uniform groove depth in the portion on the base end side of the clad mode stripper structure, it is radiated to the outside as shown by a broken line in FIGS. 5 and 6. Since the intensity of the clad mode light that is removed from the base end side decreases exponentially from the proximal end side to the distal end side, the peak intensity of the clad mode light that is radiated and removed is low at the distal end side. Hot spots occur. In the case of the clad mode stripper structure in which the depth of the groove becomes deeper from the tip side to the base end side as a whole, a hot spot having a higher peak intensity is generated at the end on the base end side. ..

However, the cladding mode stripper structure M according to the embodiment 2, as indicated by a broken line in FIG. 9, the proximal portion M _2, the depth of the groove 13 becomes shallower toward the base end side from the distal end Therefore, the intensity of the clad mode light that is radiated and removed is dispersed as a whole. Therefore, according to the clad mode stripper structure M according to the second embodiment, it is possible to suppress the generation of hot spots of clad mode light in the opposite direction.

Since the clad mode light in the reverse direction input to the clad mode stripper structure M according to the second embodiment has a lower intensity than the clad mode light in the forward direction, the clad mode light in the reverse direction in the _{proximal end side portion M 2} The weight of removing the clad mode light in the forward direction is larger than the suppression of the generation of hot spots. Therefore, the absolute value of the decreasing gradient of the depth of the groove 13 from the distal end side to the proximal end side in the proximal end side portion M ₂ is the depth of the groove 13 from the distal end side to the proximal end side in the distal end side portion M ₁ . It is preferably smaller than the absolute value of the increasing gradient.

Incidentally, the cladding mode stripper structure M according to the second embodiment, between the tip portion M ₁ and the proximal portion M _2, the depth of the groove 13 of the distal portion M ₁ and the proximal portion M ₂ It may include an intermediate portion that is less than or equal to the maximum depth of the groove 13 and is uniform.

Other effects are the same as in the first embodiment.

(Embodiment 3)
FIG. 10 shows an optical fiber 10 having a clad mode stripper structure M according to the third embodiment. The portion having the same name as that of the first embodiment is indicated by the same reference numeral as that of the first embodiment.

The clad mode stripper structure M according to the third embodiment is configured by providing a groove 13 along the length direction on the outer peripheral surface of the clad 112 in the bare optical fiber 11 exposed at the end of the optical fiber 10. A plurality of grooves 13 are formed so as to extend in the circumferential direction on the outer peripheral surface of the clad 112 in the bare optical fiber 11 exposed at the end of the optical fiber 10, and a plurality of grooves 13 are provided at intervals along the length direction. Has been done.

The clad mode stripper structure M according to the third embodiment includes a distal end side portion M ₁ and a proximal end side portion M ₂ on the proximal end side thereof. A plurality of grooves 13 are provided in each of the tip end side portion M ₁ and the proximal end side portion M _{2 , and in the tip end side portion M 1} , as shown in FIGS. 11A and 11B, the depths of the plurality of grooves 13 are provided. The depth gradually increases from the tip side to the base end side. In the proximal end side portion M ₂ , as shown in FIG. 11A, the depth of the groove 13 may be equal to or less than the maximum value of the depth of the groove 13 of the _{distal end side portion M 1 and may be uniform, and is shown in FIG. 11B.} as it may be made stepwise shallower in accordance depth of the plurality of grooves 13 go to or less maximum depth of it and the proximal side from the distal end side of the groove 13 of the distal portion M _1.

The arrangement pitch of the grooves 13 of the distal end side portion M ₁ and the proximal end side portion M ₂ may be non-uniform, but is preferably uniform from the viewpoint of ease of processing of the grooves 13. The arrangement pitches of the grooves 13 of the distal end side portion M ₁ and the proximal end side portion M ₂ may be different, but are preferably the same from the viewpoint of ease of processing of the grooves 13. The arrangement pitch of the grooves 13 of the distal end side portion M ₁ and the proximal end side portion M ₂ is, for example, 0.05 mm or more and 5 mm or less.

According to the clad mode stripper structure M according to the third embodiment, as in the first and second embodiments, the generation of hot spots of the clad mode light in the forward direction can be suppressed, and the clad mode light can be sufficiently provided even with a short length. Can be removed. Further, as shown in FIG. 11B, the depths of the plurality of grooves 13 of _{the proximal end side portion M 2} are equal to or less than the maximum value of the depths of the grooves 13 of the _{distal end side portion M 1 and go from the distal end side to the proximal end side.} As in the case of the second embodiment, it is possible to suppress the generation of hot spots of the clad mode light in the opposite direction as long as the light becomes shallower stepwise according to the above. Other configurations and effects are the same as those of Embodiments 1 and 2.

(Other embodiments)
In the first and second embodiments, the single groove 13 is formed so as to spirally extend along the length direction on the outer peripheral surface of the clad 112 at the end of the optical fiber 10. The configuration is not limited, and a plurality of grooves may be formed so as to extend in a multiple spiral shape along the length direction on the outer peripheral surface of the clad at the end of the optical fiber.

In the first and second embodiments, the groove 13 is _{formed so as to extend between the distal end side portion M 1} and the proximal end side portion M ₂ and spirally extend to the outer peripheral surface of the clad 112 at the end of the optical fiber 10. In the third embodiment, the grooves 13 are formed in each of the distal end side portion M ₁ and the proximal end side portion M ₂ so as to extend in the circumferential direction on the outer peripheral surface of the clad 112 at the end of the optical fiber 10. However, the configuration is not particularly limited to these, and the groove is formed so as to spirally extend to the outer peripheral surface of the clad at the end of the optical fiber at the distal end side portion, and at the proximal end side portion, the groove is formed. The configuration may be formed so as to extend in the circumferential direction on the outer peripheral surface of the clad at the end of the optical fiber, or vice versa.

In the first and second embodiments, the groove 13 is formed so as to spirally extend on the outer peripheral surface of the clad 112 at the end of the optical fiber 10. In the third embodiment, the groove 13 is the end of the optical fiber 10. The configuration is formed so as to extend in the circumferential direction on the outer peripheral surface of the clad 112, but the present invention is not particularly limited to these, and the groove extends in the longitudinal direction on the outer peripheral surface of the clad at the end of the optical fiber. It may be a structure formed in.

The present invention is useful in the art of clad mode stripper structures.

C Optical connector structure M Clad mode stripper structure M ₁ Tip side part M ₂ Base end side part W Work 10 Optical fiber 11 Bare optical fiber 111 Core 112 Clad 12 Jacket 13 Groove 20 Optical connector 21 Connector body 21a Bare fiber accommodating part 21b Fiber fitting part 21c Block accommodating part 22 Sealing member 23 Fiber holding member 24 Quartz block 30 Laser processing machine 31 Laser light source 32 Optical fiber cable

Claims (3)

It is a clad mode stripper structure in which a groove is provided along the length direction on the outer peripheral surface of the clad at the end of the optical fiber.
The tip side portion in which the depth of the groove becomes deeper from the tip end side to the proximal end side, and the proximal end side portion in which the depth of the groove is equal to or less than the maximum value of the groove depth of the distal end side portion. And, including
In the base end side portion, the depth of the groove becomes shallower from the tip end side to the base end side.
The absolute value of the decreasing gradient of the depth of the groove from the distal end side to the proximal end side in the proximal end side portion is the absolute value of the increasing gradient of the depth of the groove from the distal end side to the proximal end side in the distal end side portion. Clad mode stripper structure smaller than the value. In the clad mode stripper structure according to claim 1,
The groove, the distal end side portion and with crossing between the proximal portion, the cladding mode stripper structure being formed to extend spirally on the outer peripheral surface of the clad of the end of the optical fiber. In the clad mode stripper structure according to claim 1 or 2.
A clad mode stripper structure in which the length of the base end side portion is shorter than the length of the tip end side portion.

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