JP6113630B2 - Optical amplification component and fiber laser device - Google Patents

Description

  The present invention relates to an optical amplifying component and a fiber laser device, and is suitable for radiating an amplification optical fiber.

  Part of the pumping light propagating through the amplification optical fiber is changed into heat due to transmission loss in the amplification optical fiber. Also, heat is generated when an active element added to the core of the amplification optical fiber is excited by excitation light and light is emitted from the active element. Based on these heats, the amplification optical fiber tends to be short-lived. This tendency is increasing with the recent demand for higher output of fiber laser devices.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique of arranging an amplification optical fiber on a heat sink in a spiral state.

JP 2010-177553 A

  However, in the amplification optical fiber of Patent Document 1, since the end connected to the optical fiber for entering the excitation light is not disposed on the heat sink, the end is deteriorated due to heat generation. There was a problem that it was easy. Further, when the end portion of the amplification optical fiber is disposed on the heat sink, the size tends to increase.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical amplification component and a fiber laser device that can improve the life of an amplification optical fiber while reducing the size.

  As a result of intensive studies by the inventor in order to solve the above problems, when excitation light is incident only from one end of the amplification optical fiber, the heat generation amount at the one end is the largest, and the other end of the amplification optical fiber is It was found that the calorific value distribution becomes smaller as it gets closer.

  Accordingly, a new problem is how to arrange the amplification optical fiber having such a calorific value distribution on the heat sink, and the present inventor has further studied the problem to the present invention. It came.

  An optical amplification component according to the present invention includes a heat sink and an amplification optical fiber partially disposed on the heat sink, from one end of the amplification optical fiber to one end and the other end of the amplification optical fiber. A fiber portion up to a midway position is disposed on the heat radiating plate, and the fiber portion is wound on one or more rounds with a gap less than the diameter of the optical fiber for amplification from the position toward the outside. It has a section and an outer section which is separated from the inner section by a diameter equal to or larger than the diameter of the amplification optical fiber outside the inner section.

In this case, among the fiber portions arranged on the heat sink, the one end portion where the amount of heat generation is highest in the amplification optical fiber is kept away from the inner section wound over one or more rounds inside the one end portion. be able to. Therefore, deterioration of the amplification optical fiber due to heat generated at one end portion of the amplification optical fiber can be significantly reduced.
Further, the amplification optical fiber in the inner section is wound over one or more rounds with a gap less than the diameter of the amplification optical fiber, so that the size can be reduced as compared with the case where the amplification optical fiber is not wound in this state. be able to.
In this way, an optical amplification component that can improve the lifetime of the amplification optical fiber while achieving miniaturization is realized.

  Further, it is preferable that the amplification optical fiber in the outer section is wound around the inner section for one or more rounds with a gap larger than the diameter of the amplification optical fiber.

In this case, with the amplification optical fiber adjacent in the outer section being separated from the amplification optical fiber adjacent in the inner section, the one end portion where the heat generation amount is highest in the amplification optical fiber is the outermost. Can be located. Therefore, it is possible to further reduce the deterioration of the amplification optical fiber due to the heat generated at one end portion of the amplification optical fiber.
Further, the size can be further reduced as compared with the case where the amplification optical fiber in the outer section is not wound.
Furthermore, since the amplification optical fiber in the outer section is wound with a gap larger than the diameter of the amplification optical fiber, the position to be arranged on the heat sink can be adjusted as compared with the case where the gap is not provided. Easy to do. Therefore, the amplification optical fiber can be disposed on the heat sink relatively easily while maintaining the winding interval of the amplification optical fiber in the inner section below the diameter of the amplification optical fiber.

  Further, it is preferable that the amplification optical fiber in the outer section is separated from the inner section toward the tip.

  In this case, the one end portion where the heat generation amount is highest in the amplification optical fiber can be moved away from not only the inner section but also the amplification optical fiber in the vicinity of the one end portion. Therefore, it is possible to further reduce the deterioration of the amplification optical fiber due to the heat generated at one end portion of the amplification optical fiber.

  Further, the heat radiating plate has a structure in which the heat dissipation amount of the heat radiating portion where the one end portion of the amplification optical fiber in the outer section is disposed is larger than the heat dissipation amount of the heat radiating portion where the inner section is disposed. It is preferred that

  In this case, the one end portion where the heat generation amount is highest in the amplification optical fiber can be intensively cooled. Therefore, it is possible to further reduce the deterioration of the amplification optical fiber due to the heat generated at one end portion of the amplification optical fiber.

  Moreover, a recessed part is formed in the heat radiating surface of the heat radiating plate, and the fiber portion is disposed in the recessed part without partitioning adjacent fibers.

  In this case, it is possible to suppress stress from being applied to the fiber portion from the outside as compared with the case where the fiber portion is not disposed in the recess. Further, since the restriction on the space for placing the amplification optical fiber is relaxed compared to the case where the adjacent fibers are partitioned, it is easy to adjust the position of the fiber portion to be placed in the recess.

  Further, the fiber laser device of the present invention, the light amplification component described above, the seed light source and the excitation light source, and the seed light emitted from the seed light source is incident on the core at one end of the amplification optical fiber, And an optical coupler for entering the excitation light emitted from the excitation light source into a clad at one end of the optical fiber for amplification.

  Alternatively, the optical amplifying component described above, a pumping light source, an optical coupler that enters pumping light emitted from the pumping light source into a clad at one end of the optical fiber for amplification, and a core of the optical fiber for amplification are added. A first mirror that reflects at least part of the light emitted by the active element, and a second mirror that reflects the light reflected by the first mirror with a lower reflectance than the first mirror. And

  Such a fiber laser device is provided with the optical amplification component as a part of its constituent elements. Therefore, compared with a case where the optical amplification component is not provided, the fiber laser device is less susceptible to heat generated at one end portion of the amplification optical fiber. This can significantly reduce the deterioration of the amplification optical fiber. Further, the size can be reduced as compared with the case where the optical amplification component is not provided. In this way, a fiber laser device that can improve the life of the amplification optical fiber while achieving miniaturization is realized.

  As described above, according to the present invention, it is possible to provide an optical amplification component and a fiber laser device capable of improving the life of an amplification optical fiber while achieving downsizing.

It is a figure which shows the optical amplification component in 1st Embodiment. It is a figure which shows the mode of the fiber cross section orthogonal to the length direction of the optical fiber for amplification. It is a figure which shows the cross section which passes along XX of FIG. It is a figure which shows the emitted-heat amount distribution of the optical fiber for amplification when excitation light injects from the end of the optical fiber for amplification. It is a figure which shows the optical amplification component in 2nd Embodiment. It is a figure which shows the optical amplification component in 3rd Embodiment. It is a figure which shows the other structural example (1) of a heat sink. It is a figure which shows the other structural example (2) of a heat sink. It is a figure which shows the fiber laser apparatus in 4th Embodiment. It is a figure which shows the fiber laser apparatus in 5th Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the invention will be described in detail with reference to the drawings.

(1) 1st Embodiment FIG. 1: is a figure which shows the optical amplification component 1 in 1st Embodiment. As shown in FIG. 1, the optical amplification component 1 of this embodiment includes a heat sink 10 and an amplification optical fiber 20 fixed to the heat dissipation surface of the heat sink 10 as main components.

  The heat sink 10 is a plate material for radiating heat to lower the temperature. The material of the heat sink 10 is a metal or alloy such as silver, copper, gold, or aluminum, and the shape of the heat sink 10 is, for example, a rectangular parallelepiped shape.

  FIG. 2 is a diagram showing a state of a fiber cross section orthogonal to the length direction of the amplification optical fiber 20. As shown in FIG. 2, the amplification optical fiber 20 includes a core 21 to which one or more kinds of active elements are added, a first cladding 22 that covers the outer peripheral surface of the core 21, and an outer peripheral surface of the first cladding 22. The structure has a second clad 23 to be covered and a covering layer 24 surrounding the second clad 23.

  The refractive index of the core 21 is higher than the refractive index of the first cladding 22, the refractive index of the first cladding 22 is higher than the refractive index of the second cladding 23, and the refractive index of the second cladding 23 is the same as that of the coating layer 24. Lower than the refractive index.

  Examples of active elements include rare earth elements such as erbium (Er), ytterbium (Yb), and neodymium (Nd). Examples of active elements other than rare earth elements include bismuth (Bi).

  A part of the amplification optical fiber 20 having such a structure is disposed on the heat sink 10. That is, as shown in FIG. 1, a fiber portion from one end E1 of the amplification optical fiber 20 to a midpoint position (hereinafter referred to as a midway position) RP between the one end E1 and the other end E2 of the amplification optical fiber 20 20A is arranged on the heat sink 10.

  The midway position RP is a position that should start to be separated from the heat sink 10 and is arbitrarily determined. For example, the center in the length direction of the amplification optical fiber 20 may be determined as the intermediate position RP, and the position shifted from the center toward the one end E1 or the other end E2 may be determined as the intermediate position RP.

  The fiber portion 20A has an inner section SC1 and an outer section SC2. The inner section SC1 is wound over one or more turns in a state having a gap IL1 less than the diameter D of the amplification optical fiber 20 from the midway position RP toward the outside. As shown in FIG. 1, the gap IL1 is the shortest distance from the opposite inner peripheral surface to the outer peripheral surface of the adjacent amplification optical fibers 20 in the inner section SC1.

  The gap IL1 between adjacent amplification optical fibers in the inner section SC1 is substantially the same in FIG. 1, but the gap IL1 may be different as long as it is less than the diameter D of the amplification optical fiber 20. Further, a part or all of the adjacent amplification optical fibers 20 in the inner section SC1 may be in contact with each other, or there may be an intersecting portion.

  The outer section SC2 is separated from the inner section SC1 by more than the diameter D of the amplification optical fiber 20 outside the inner section SC1. In the case of the present embodiment, the outer section SC2 is wound around the inner section SC1 for one or more turns in a state having a gap SL2 having a diameter D or more of the amplification optical fiber 20. As shown in FIG. 1, the gap IL <b> 2 is the shortest distance from the opposite inner peripheral surface to the outer peripheral surface of the adjacent amplification optical fiber 20 in the outer section SC <b> 2.

  Note that the gap IL2 between adjacent amplification optical fibers in the outer section SC2 is approximately the same in FIG. 1, but the gap IL2 may be different as long as it is equal to or larger than the diameter D of the amplification optical fiber 20.

  Further, in the outer section SC2, the vicinity including the one end E1 of the amplification optical fiber 20 is not wound in FIG. 1, but is arranged in a straight line, but the vicinity may be wound. Further, if the amplification optical fiber 20 in the outer section SC2 is separated from the inner section SC1 by the diameter D or more of the amplification optical fiber 20, the entire amplification optical fiber 20 in the outer section SC2 is not wound. May be.

  On the other hand, in the fiber portion 20B from the midway position RP to the other end E2 of the amplification optical fiber, it is not disposed on the heat dissipation surface of the heat sink 10 and the other end E2 of the amplification optical fiber is not located on the heat sink 10. Located outside. For example, the fiber portion 20B is arranged so as to extend to the external optical component after passing through the upper part of the inner section SC1 and the outer section SC2.

  FIG. 3 is a view showing a cross section taken along line XX of FIG. In FIG. 3, for the sake of convenience, the cross section of the amplification optical fiber 20 is shown in a simplified manner. As shown in FIG. 3, a concave portion CP is formed in a portion other than the central portion and the peripheral portion on the heat radiating surface of the heat radiating plate 10.

  The fiber portion 20A is disposed in the recess CP without partitioning adjacent fibers. That is, the bottom surface of the recess CP is flat, and the fiber portion 20A is placed on the bottom surface in a state having the inner section SC1 and the outer section SC2.

  In such an optical amplification component 1, the end surface of the first cladding 22 at the one end E <b> 1 of the amplification optical fiber 20 is an end surface on which excitation light is to be incident.

  When excitation light is incident from the end face of the first cladding 22, the excitation light propagates through the first cladding 22 and the core 21 in the amplification optical fiber 20. At this time, the active element added to the core 21 is excited by the excitation light, and light having a specific wavelength is emitted from the active element.

  FIG. 4 is a diagram showing a heat generation distribution of the amplification optical fiber 20 when excitation light is incident from one end E1 of the amplification optical fiber 20. As shown in FIG. As shown in FIG. 4, when the excitation light is incident from one end E <b> 1 of the amplification optical fiber 20, the heat generation amount at the one end portion is the largest, and the heat generation amount decreases as it approaches the other end of the amplification optical fiber 20. It turns out that it becomes distribution.

  The reason for this calorific value distribution is that the heat generation at each location of the amplification optical fiber 20 is normally proportional to the energy amount of the excitation light passing through that portion.

  That is, the heat generation of the amplification optical fiber 20 occurs because a part of the pumping light is changed into heat due to the transmission loss of the amplification optical fiber 20 at each location of the amplification optical fiber 20. Therefore, the heat generation amount is roughly proportional to the product of the transmission loss at that position and the energy amount of the excitation light. Since the transmission loss of the amplification optical fiber 20 is almost constant everywhere, the amount of heat generated by the amplification optical fiber 20 increases as the amount of excitation light energy increases.

  In the case of the present embodiment, the end face of the first cladding 22 at the one end E1 of the amplification optical fiber 20 is the end face to which the pump light is to be incident, so that the energy amount of the pump light at the one end portion is the largest. Thereafter, the excitation light propagates through the amplification optical fiber 20 toward the other end E2, and at this time, a part of the energy of the excitation light is changed to heat due to the transmission loss of the amplification optical fiber 20, and thus the amount of energy. Gradually decreases. Since the transmission loss of the amplifying optical fiber 20 is significantly larger than that of a normal communication optical fiber, the reduction in the amount of energy due to the propagation of pumping light is also significantly large. Therefore, the difference in the amount of heat generated between the one end portion and the other end portion of the amplification optical fiber 20 is large.

  As described above, in the optical amplification component 1 of the present embodiment, the fiber portion 20 </ b> A including the one end E <b> 1 where the excitation light should enter in the amplification optical fiber 20 is disposed on the heat sink 10. The inner section SC1 of the fiber portion 20A is wound over one or more turns in a state having a gap IL1 less than the diameter D of the amplification optical fiber 20 from the midway position RP outward. On the other hand, the outer section SC2 of the fiber portion 20A is separated from the inner section SC1 by more than the diameter D of the amplification optical fiber 20 outside the inner section SC1.

  For this reason, the optical amplifying component 1 in the present embodiment has an inner section in which one end portion where the amount of heat generation is highest among the fiber portions 20A arranged on the heat sink 10 is wound over one or more rounds inside the one end portion. Can be moved away from SC1. Therefore, deterioration of the amplification optical fiber 20 due to heat generated at one end portion of the amplification optical fiber 20 can be significantly reduced.

  Further, the amplification optical fiber 20 in the inner section SC1 is in a state of being wound over one or more turns with a gap IL1 less than the diameter D of the amplification optical fiber 20, and therefore, compared with a case where the amplification optical fiber 20 is not wound in this state. Miniaturization can be achieved.

  By the way, the outer section SC2 in the present embodiment is wound around the inner section SC1 over one or more rounds with a gap SL2 having a diameter D or more of the amplification optical fiber 20.

  For this reason, in the state where the amplification optical fiber adjacent in the outer section SC2 is separated from the amplification optical fiber adjacent in the inner section SC1, the one end portion where the heat generation amount is highest in the amplification optical fiber 20 is the outermost. Can be located. Therefore, it is possible to further reduce the deterioration of the amplification optical fiber 20 due to heat generated at one end portion of the amplification optical fiber 20. Further, the size can be further reduced as compared with the case where the amplification optical fiber 20 in the outer section SC2 is not wound.

  In addition, since the amplification optical fiber 20 in the outer section SC2 is wound in a state having a gap SL2 that is equal to or larger than the diameter D of the amplification optical fiber 20, the heat sink is compared with a case where the gap SL2 is not provided. 10 is easy to adjust the position to be placed. Therefore, the amplification optical fiber 20 can be disposed on the heat sink 10 relatively easily while maintaining the winding interval of the amplification optical fiber 20 in the inner section SC1 to be less than the diameter D of the amplification optical fiber.

  In addition, a concave portion CP is formed on the heat radiating surface of the heat radiating plate 10 in the present embodiment, and the fiber portion 20A is disposed in the concave portion CP without partitioning adjacent fibers.

  For this reason, compared with the case where fiber part 20A is not arrange | positioned in the recessed part CP, it can suppress that stress is added to the fiber part 20A from the outside. Further, since the restriction on the space for arranging the fiber portion 20A is relaxed compared to the case where adjacent fibers are partitioned, the position of the fiber portion 20A to be arranged in the recess CP can be easily adjusted.

(2) Second Embodiment Next, a second embodiment will be described in detail with reference to the drawings. In addition, about the component which is the same as that of 1st Embodiment, or equivalent, except the case where it demonstrates especially, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted.

  FIG. 5 is a diagram showing the optical amplification component 2 in the second embodiment. As shown in FIG. 5, in the optical amplification component 2 in the present embodiment, only the arrangement mode of the outer section SC2 in the amplification optical fiber 20 is different from that in the first embodiment.

  Specifically, the amplification optical fiber 20 in the outer section SC2 in this embodiment is separated from the inner section SC1 toward the tip. That is, the gap IL2 between the adjacent amplification optical fibers in the outer section SC2 gradually increases toward the tip.

  According to such an optical amplification component 2, the one end portion where the amount of heat generated in the amplification optical fiber 20 is the highest can be moved away from not only the inner section SC 1 but also the amplification optical fiber 20 in the vicinity of the one end portion. it can. Therefore, it is possible to further reduce the deterioration of the amplification optical fiber 20 due to heat generated at one end portion of the amplification optical fiber 20.

(3) Third Embodiment Next, a third embodiment will be described in detail with reference to the drawings. In addition, about the component which is the same as that of the said embodiment, or the equivalent except the case where it demonstrates especially, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted.

  FIG. 6 is a diagram showing the optical amplification component 3 in the third embodiment. As shown in FIG. 6, the optical amplification component 3 in the present embodiment includes a heat radiating plate 11 having a structure different from that of the heat radiating plate 10 instead of the heat radiating plate 10 in the first embodiment.

  Specifically, the heat dissipation plate 30 in the present embodiment has a second part PA where one end E1 portion of the amplification optical fiber 20 in the outer section SC2 is disposed, rather than the heat dissipation amount of the first part in which the inner section SC1 is disposed. The heat dissipation amount is larger.

  For example, when the first part is formed using aluminum and the second part PA is formed using copper having a smaller thermal resistance than aluminum, the heat dissipation of the second part PA is larger than the heat dissipation amount of the first part. The amount increases.

  Further, for example, a convex portion called a fin is formed on the surface portion opposite to the heat radiation surface of the first portion and the second portion PA, and the length of the convex portion of the second portion PA is the length of the convex portion of the first portion When it is made larger than the length, the heat dissipation amount of the second part PA becomes larger than the heat dissipation amount of the first part.

  Further, for example, when an air-cooled, water-cooled, or electronic cooling type cooling mechanism is provided only for the second part PA, the heat dissipation amount of the second part PA is larger than the heat dissipation amount of the first part. .

  According to such an optical amplifying component 3, the one end portion where the amount of heat generated in the amplification optical fiber 20 is the highest can be intensively cooled. Therefore, it is possible to further reduce the deterioration of the amplification optical fiber 20 due to heat generated at one end portion of the amplification optical fiber 20.

  If the heat dissipation amount of the second part PA is larger than the heat dissipation amount of the first part, the heat dissipation part PA2 of the heat dissipation part PA2 such as the heat sink 12 shown in FIG. 7 or the heat sink 13 shown in FIG. The range does not matter. Moreover, the heat sinks 11-13 shown in FIGS. 6-8 are applicable instead of the heat sink 10 in the said 2nd Embodiment.

(4) Fourth Embodiment Next, a fourth embodiment will be described in detail with reference to the drawings. In addition, about the component which is the same as that of the said embodiment, or the equivalent except the case where it demonstrates especially, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted.

FIG. 9 is a diagram showing a fiber laser device according to the fourth embodiment. As shown in FIG. 9, the fiber laser device 100 according to the present embodiment includes an MO-PA (Master Oscillator Power).
Amplifier) type fiber laser device.

  The fiber laser device 100 includes the optical amplification component 1 according to the first embodiment, a seed light source 31, a plurality of excitation light sources 32, and an optical coupler 33 as main components. Note that the optical amplifying component 1 shown in FIG. 9 is simply shown, unlike the case shown in FIG.

  The seed light source 31 emits seed light and is, for example, a laser light source composed of a laser diode, a Fabry-Perot type or a fiber ring type laser light source, or the like.

  The plurality of excitation light sources 32 emit excitation light and are, for example, laser diodes.

  The optical coupler 33 causes the seed light emitted from the seed light source 31 to enter from the core end surface of the one end E1 of the amplification optical fiber 20, and the excitation light emitted from the excitation light source 32 to the one end E1 of the amplification optical fiber 20. The light is incident from the first clad end face.

  In the present embodiment, the seed light emitted from the seed light source 31 is incident on the optical coupler 33 via the incident optical fiber 40. The incident optical fiber 40 is, for example, a single mode fiber, and the core on one end side of the incident optical fiber 40 and the seed light source 31 are optically coupled, and the other end side of the incident optical fiber 40 is also connected. The core and the core 21 on the one end E1 side of the amplification optical fiber 20 are optically coupled via an optical coupler 33.

  Further, the excitation light emitted from the excitation light source 32 is incident on the optical coupler 33 through the excitation light incident fiber 50. The pumping light incident fibers 50 are, for example, multimode fibers, and the number of the pumping light incident fibers 50 is the same as the number of pumping light sources 32. One excitation light source 32 is optically coupled to one end core of each excitation light incident fiber 50, and the other end core of the excitation light incident fiber 50 and one end E 1 side of the amplification optical fiber 20. The first cladding 22 is optically coupled via an optical coupler 33.

  The output optical fiber 70 is connected to the other end E2 of the amplification optical fiber 20. The output optical fiber 70 is, for example, a single mode fiber, and the core end surface on one end side of the output optical fiber 70 and the core end surface on the other end E2 side of the amplification optical fiber 20 are fused.

  In the fiber laser device 100 according to the present embodiment, when seed light is incident from the core end surface on the one end E1 side of the amplification optical fiber 20, the seed light is directed from one end E1 to the other end E2 of the amplification optical fiber 20. It propagates through the core 21.

  On the other hand, when excitation light is incident from the first cladding end face on the one end E1 side of the amplification optical fiber 20, the excitation light is directed from the one end E1 to the other end E2 of the amplification optical fiber 20 and the first cladding 22 and the core. 21 is propagated.

  The active element added to the core 21 is excited by the excitation light propagating through the first cladding 22 and the core 21, and the active element in the excited state causes stimulated emission by the seed light propagating through the core 21. The seed light is amplified due to the stimulated emission, and the amplified seed light is output from the other end E 2 of the amplification optical fiber 20 to the output optical fiber 70.

  Such a fiber laser device 100 includes the optical amplification component 1 of the first embodiment as a part of its constituent elements. For this reason, the fiber laser device 100 according to the present embodiment has a marked deterioration in the amplification optical fiber due to the heat generated at one end of the amplification optical fiber, compared to the case where the optical amplification component 1 is not provided. Can be reduced. Further, the fiber laser device 100 of the present embodiment can be downsized as compared with the case where the optical amplification component 1 is not provided.

  In the fiber laser device 100 according to the present embodiment, the optical amplification component 2 of the second embodiment or the optical amplification component 3 of the third embodiment may be applied instead of the optical amplification component 1. Even when the optical amplification component 2 or the optical amplification component 3 is applied, it is possible to reduce deterioration of the amplification optical fiber due to heat generated at one end portion of the amplification optical fiber, and to reduce the size. Can be planned.

(5) Fifth Embodiment Next, a fifth embodiment will be described in detail with reference to the drawings. In addition, about the component which is the same as that of the said embodiment, or the equivalent except the case where it demonstrates especially, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted.

  FIG. 10 is a diagram showing a fiber laser device according to the fifth embodiment. As shown in FIG. 10, the fiber laser device 110 in this embodiment is a resonance type fiber laser device.

  The fiber laser device 110 includes an optical amplification component 1 according to the first embodiment, a plurality of excitation light sources 32, an optical coupler 33, a first FBG (Fiber Bragg Grating) 36 serving as a first mirror, and a second mirror serving as a second mirror. 2FBG37 is provided as a main configuration. Note that the optical amplifying component 1 shown in FIG. 10 is simply shown, unlike the case shown in FIG.

  The first FBG 36 is provided in the incident optical fiber 40 and has a structure in which high refractive index portions are repeated at a constant period along the longitudinal direction of the amplification optical fiber 20. The first FBG 36 is adjusted so as to reflect light having a wavelength of at least a part of light emitted by the active element of the amplification optical fiber 20 in the excited state.

  The second FBG 37 is provided in the output optical fiber 70 and has a structure in which a portion having a high refractive index is repeated at a constant period along the longitudinal direction of the amplification optical fiber 20. The second FBG 37 is adjusted to reflect light having the same wavelength as the light reflected by the first FBG 36 with a lower reflectance than the first FBG 36.

  In the fiber laser device 110 according to the present embodiment, the pumping light incident on the first cladding 22 in the amplification optical fiber 20 propagates through the first cladding 22 and the core 21 in the amplification optical fiber 20 and is cored by the pumping light. The active element added to 21 is excited, and light having a specific wavelength is emitted from the active element.

  This light propagates through the core 21 of the amplification optical fiber 20, light of a specific wavelength travels between the first FBG 36 and the second FBG 37 and is amplified, and a part of the amplified light passes through the second FBG 37. The light is emitted from the output end of the amplification optical fiber 20 to the output optical fiber 70.

  Such a fiber laser device 110 includes the optical amplification component 1 of the first embodiment as a part of its constituent elements. For this reason, the fiber laser device 110 of the present embodiment, like the fiber laser device 100, can significantly reduce deterioration of the amplification optical fiber due to heat generated at one end of the amplification optical fiber. Can do. Further, the fiber laser device 110 of the present embodiment can be downsized as compared with the case where any of the optical amplification components 1 is not provided.

  In the fiber laser device 110 according to the present embodiment, the optical amplification component 2 of the second embodiment or the optical amplification component 3 of the third embodiment may be applied instead of the optical amplification component 1. Even when the optical amplification component 2 or the optical amplification component 3 is applied, it is possible to reduce deterioration of the amplification optical fiber due to heat generated at one end portion of the amplification optical fiber, and to reduce the size. Can be planned.

  As mentioned above, although 1st Embodiment-5th Embodiment were described as an example, this invention is not limited to the said embodiment. The components in the optical amplification components 1 to 3 and the fiber laser device 100 or the fiber laser device 110 described above are combined, omitted, or modified as appropriate without departing from the purpose of the present application, in addition to the contents shown in the embodiment. A well-known technique can be added.

  The optical amplifying component and the fiber laser device according to the present invention can be used in the industrial field of handling an optical fiber for amplification.

DESCRIPTION OF SYMBOLS 1-3 ... Optical amplification component 10-13 ... Heat sink 20 ... Amplifying optical fiber 21 ... Core 22 ... 1st clad 23 ... 2nd clad 24 ... Covering layer DESCRIPTION OF SYMBOLS 31 ... Seed light source 32 ... 1st excitation light source 33 ... 2nd excitation light source 34 ... Incident side optical coupler 35 ... Output side optical coupler 40 ... Incident optical fiber 50 ... Pumping light incident fiber 60 ... Pumping light incident fiber 70 ... Output optical fiber 100, 110 ... Fiber laser device SC1 ... Inner section SC2 ... Outer section

Claims (7)

A heat sink, and an amplification optical fiber partially disposed on the heat sink,
A fiber portion from one end of the amplification optical fiber to an intermediate position between one end and the other end of the amplification optical fiber is disposed on the heat sink,
The fiber portion has an inner section that is wound over one or more turns in a state having a gap smaller than the diameter of the amplification optical fiber from the position toward the outside, and the amplification section from the inner section outside the inner section. An optical amplifying component comprising an outer section separated by a diameter equal to or greater than the diameter of the optical fiber. 2. The optical amplification according to claim 1, wherein the amplification optical fiber in the outer section is wound over the circumference of the inner section in a state having a gap larger than the diameter of the amplification optical fiber. parts. 3. The optical amplification component according to claim 1, wherein the amplification optical fiber in the outer section is separated from the inner section toward the tip. 4. The heat radiating plate has a structure in which the heat dissipation amount of the heat radiating portion where the one end portion of the amplification optical fiber in the outer section is disposed is larger than the heat radiating amount of the heat radiating portion where the inner section is disposed. The optical amplification component according to any one of claims 1 to 3, wherein 5. The concave portion is formed in the heat radiating surface of the heat radiating plate, and the fiber portion is disposed in the concave portion without partitioning adjacent fibers. An optical amplification component as described in 1. The optical amplification component according to any one of claims 1 to 5,
A seed light source and an excitation light source;
An optical coupler that makes the seed light emitted from the seed light source enter the core at one end of the amplification optical fiber and makes the excitation light emitted from the excitation light source enter the cladding at one end of the amplification optical fiber; A fiber laser device comprising: The optical amplification component according to any one of claims 1 to 5,
An excitation light source;
An optical coupler that makes the excitation light emitted from the excitation light source incident on the cladding at one end of the amplification optical fiber;
A first mirror that reflects at least part of the light emitted by the active element added to the core of the amplification optical fiber;
A fiber laser device comprising: a second mirror that reflects light reflected by the first mirror with a lower reflectance than the first mirror.

Images