JP2007142463A - Optical fiber light guiding device, optical fiber transmission type laser device, and pulse laser oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to transmit pulse laser light of high peak output by an optical fiber without damaging the optical fiber. <P>SOLUTION: An optical fiber light guiding device guides a pulse laser light from a pulse laser oscillator 10f to an optical fiber for transmission. The device has a micro-lens array 27a composed by arranging condenser lenses 27a in the shape of compound eyes and introducing the pulse laser light from one end, and a condensing optical system 27a1 condensing the pulse laser light output from the other end of the micro-lens array into the optical fiber for transmission. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for laser light transmission using an optical fiber, and in particular, when transmitting pulsed laser light having a high peak output, it is possible to prevent damage to the optical fiber and perform good transmission in a healthy state. The present invention relates to a fiber light guide device, an optical fiber transmission laser device, and a pulse laser oscillator.

  In recent years, for example, laser peening has been developed for the purpose of improving the strength of various members that require preventive maintenance and high durability, such as reactor internal structures, and some applications are being studied. . In this apparatus, an extremely large pulse laser beam having a peak output of, for example, 10 MW or more is used. In addition, a technique for removing a surface layer of a metal material or performing a trace analysis of an element by using such a high-peak output pulse laser beam has been developed.

  In an apparatus using pulsed laser light having a high peak output, such as a laser peening apparatus, as described above, spatial transmission using a reflection mirror is generally employed as a means for transmitting pulsed laser light. . However, for example, when the transmission path is complicated and long, or when the transmission path requires a degree of freedom, a large number of reflecting mirrors are used, and their positions and angles are precisely controlled, or Therefore, there is a problem that the apparatus becomes complicated because it needs to be controlled. In particular, in a laser peening apparatus that performs preventive maintenance of reactor internal structures, it is necessary to remotely control the reflection mirror from the viewpoint of reducing the exposure of workers, which further complicates the apparatus. Further, in spatial transmission using a reflection mirror, it is extremely difficult to transmit a narrow portion such as the inside of a narrow tube having a diameter of less than 1 cm over a long distance.

  In order to solve the above problems, there is a demand for transmission using an optical fiber that can easily realize optical transmission with a high degree of freedom. However, when a pulse laser beam having a high peak output is introduced into the optical fiber, the optical fiber itself may be damaged due to the extremely high peak output. As means for avoiding this, for example, the use of an optical fiber light guiding device by image formation or a tapered fiber has recently been studied.

  First, an example of an optical fiber light guide device using image formation will be described. FIG. 22 shows the configuration. This apparatus includes an aperture 1 (diameter d), a coupling lens 2 (magnification m), and an optical fiber 3 held by an optical fiber holder 3a, which are sequentially arranged on the optical path of the pulsed laser light L, and an aperture surface. A and the end face B of the optical fiber are arranged so as to be conjugate (imaging relationship). The position of the aperture 1 is set so that no significant peak is included in the energy density distribution of the pulsed laser light L to be cut out.

  In the apparatus configured as described above, the pulse laser beam L is cut out by the aperture 1 (beam diameter d), and the cut out image is reduced by the imaging lens 2 (beam diameter md), and the optical fiber end face B ( Projected to the core diameter a> md). In this case, since the peak of the energy density is not included in the pulse laser beam L at the aperture cut-out position, the peak of the energy density is not included even in the optical fiber end surface B. Therefore, the optical fiber 3 on the optical fiber end surface B Damage can be avoided.

Next, an example of a tapered fiber will be described. FIG. 23 shows the configuration. The taper fiber 4 to be used is an optical fiber having a tapered cross section at the light incident side end, and the core diameter a ₀ at the fiber end face is larger than the core diameter a of the fiber main part (a _0). > A).

The pulsed laser light L is first condensed by the condenser lens 5 and then on the end face of the tapered fiber 4 with a beam diameter d that is larger than the core diameter a at the center of the optical fiber and smaller than the core diameter a ₀ of the end face. Irradiated (a ₀ >d> a). According to this means, the energy density of the pulse laser L at the end face of the optical fiber can be reduced, and therefore fiber damage at the end face of the optical fiber can be avoided.

  By the way, in the optical fiber light guide by imaging shown in FIG. 22, damage can be avoided by eliminating the local peak of the energy density at the end face of the optical fiber. Since the laser beam with high directivity is reflected at the boundary surface between the concave core and the clad, the laser beam converges finely and damages the optical fiber.

  Further, even when the tapered fiber shown in FIG. 23 is used, damage to the end face of the optical fiber can be avoided by reducing the energy density, but the laser beam is converged inside the optical fiber by the same action as described above. Damage.

  As described above, recently, it has been desired to transmit high-peak-power pulsed laser light using an optical fiber, but no means for realizing such a request is known.

  As described above, the conventional technique has a problem that damage on the end face of the optical fiber can be avoided, but damage due to convergence other than at the end cannot be prevented.

  The present invention has been made to cope with such a situation, and an object of the present invention is to provide an optical fiber transmission type laser apparatus capable of transmitting a pulse laser beam having a high peak output through an optical fiber without damaging the optical fiber. An object of the present invention is to provide a pulse laser oscillator and an optical fiber light guide device.

  In order to achieve the above object, an invention according to claim 1 is an optical fiber light guide device for guiding pulse laser light from a pulse laser oscillator to a transmission optical fiber, wherein condensing lenses are arranged in a compound eye shape. A microlens array for introducing the pulse laser light from one end side, and a condensing optical system for condensing the pulse laser light emitted from the other end side from the microlens array on the transmission optical fiber. An optical fiber light guiding device is provided.

  A second aspect of the present invention is an optical fiber transmission type laser device comprising a pulse laser oscillator, the optical fiber light guiding device according to the first aspect, and a transmission optical fiber that transmits the pulse laser light. provide.

  According to a third aspect of the present invention, there is provided a rear mirror, an output mirror provided opposite to the rear mirror, an oscillator provided between the rear mirror and the output mirror, a laser resonator having pulse generation means, and a condensing lens. A microlens array that is arranged in a planar manner in a compound eye and introduces a pulsed laser beam emitted from the laser resonator from one end side, and amplifies the pulsed laser beam emitted from the other end side of the microlens array. A pulse laser oscillator characterized by having an optical amplification means for emitting light is provided.

  According to a fourth aspect of the present invention, there is provided the pulse laser oscillator according to the third aspect, a condensing optical system for condensing the pulse laser light emitted from the pulse laser oscillator, and a transmission light for transmitting the condensed pulse laser light. An optical fiber transmission type laser device characterized by comprising a fiber is provided.

  According to the first aspect of the present invention, the pulse laser beam having high spatial coherence is reduced to the transmission optical fiber after the spatial coherence is lowered and the spatial intensity distribution is made uniform through the optical fiber light guide device. Since the laser beam is introduced, the laser beam does not converge finely inside the pulse laser beam, and there is no local intensity peak at the introduction portion of the optical fiber, so that the optical fiber is not damaged. Therefore, by using this optical fiber light guide device, pulse laser light having a high peak output can be transmitted through the optical fiber without damaging the optical fiber.

  According to the invention of claim 2 or 4, damage to the optical fiber is caused by providing means for reducing the coherence of the pulse laser beam in at least one of the pulse laser oscillator, the optical fiber light guide device, and the optical fiber. Thus, transmission of pulsed laser light having a high peak output can be performed.

  According to the invention of claim 3, since the pulse laser beam is emitted from the pulse laser oscillator with a low spatial coherence and a large spread angle representing directivity, such a pulse laser beam is used for transmission. Even when introduced into pulsed laser light, it does not converge finely inside the optical fiber. Therefore, by using this pulse laser oscillator as a light source, pulse laser light having a high peak output can be transmitted through the optical fiber without damaging the optical fiber.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment (FIG. 1)]
FIG. 1 is a block diagram showing a pulse laser oscillator.

  The pulse laser oscillator 10a of this embodiment is a Q-switch type laser oscillator, and includes a laser resonator 15 including a rear mirror 11, a Q switch 12, an oscillator 13, and an output mirror 14, and an optical amplification amplifier 16. It has been configured. As the oscillator 13, for example, a YAG laser rod using a flash lamp as an excitation light source is used. Further, for example, a plane reflecting mirror or the like is used for the rear mirror 11 and the output mirror 14, and a Fabry-Perot resonator or the like is configured.

  In this, in this embodiment, the surface 11a used as the reflective surface of the rear mirror 11 is a sand surface. The particle size of the sand surface is, for example, # 245-1500 in sand numbers.

Next, the operation of the Q-switch type laser oscillator 10a will be described. From the laser resonator 15, a short time width by the action of the Q-switch 12, the pulse laser light L ₁ is large ratio of peak output to average power is emitted, the pulsed laser light L ₁ is the laser resonator 15 Since the surface 11a of the rear mirror 11 is a sand surface, it diverges moderately. The pulse laser beam L ₁ emitted from the laser resonator 15 is transmitted to the optical amplification amplifier 16 and amplified as the pulse laser beam L ₂ having a very high peak output, but the pulse laser beam L ₁ before amplification is moderate. due to the divergent, pulsed laser light L ₂ of the amplified also a laser light moderately divergent. That is, from this Q-switch type laser oscillator 10a, compared with the case where the surface of the rear mirror 11 of the laser resonator 15 is a mirror surface, the pulse laser beam L ₁ having a low spatial coherence and a large divergence angle representing directivity. There is emitted, the pulsed laser light L ₂ after the amplification also becomes coherence large spread angle low.

According to this embodiment having such a configuration, since the surface 11a of the rear mirror 11 of the laser resonator 15 is a sand surface, the Q-switched laser oscillator 10a has low spatial coherence and directivity. pulsed laser light L ₂ is greater spread angle indicating is emitted. Such a pulse laser beam L ₂ is a high spatial coherence, as compared with the divergence angle is small normal pulse laser light representing directivity, Atsumarikotaba when condensed by using the same condensing optical system The diameter becomes larger. That is, even when introduced into the optical fiber for transmission (not shown) the pulse laser light L _2, not converged finely within the optical fiber. Therefore, if this Q-switch type laser oscillator 10a is used as a light source, pulse laser light having a high peak output can be transmitted through the optical fiber without damaging the optical fiber.

[Second Embodiment (FIG. 2)]
Next, a second embodiment of the present invention will be described. FIG. 2 is a block diagram of a pulse laser oscillator according to the second embodiment of the present invention.

  This pulse laser oscillator 10b is a Q-switch type laser oscillator, and has a laser resonator 15 similar to that of the first embodiment except that the surface of the rear mirror 11 is a mirror surface. The laser resonator 15 is denoted by the same reference numerals as those in FIG.

In this embodiment, a diffusion optical fiber 17 is provided at the light exit position of the laser resonator 15. The diffusion optical fiber 17 is a step index type optical fiber having a quartz core, for example, and has, for example, a U-shape. Then, the pulse laser beam L ₁₁ emitted from the laser resonator 15 enters the diffusion optical fiber 17 from one end side through the first reflection mirror 18 and the condensing lens 19, and others. emitted from the end side as a pulse laser beam L _12, it is led through a second condenser lens 20 and the reflecting mirror 21 in the optical amplification amplifier 16, so as to be emitted after amplification as a pulse laser beam L ₂ ing.

Next, the operation of the Q-switch type laser oscillator 10b will be described in detail. From the laser oscillator 15, a short time width and the average output is low, the pulse laser light L ₁₁ is large ratio of peak output to the which is emitted. The pulsed laser light L ₁₁ is bent by the first reflecting mirror 18, condensed by the first lens 19, and introduced into the inside from one end of the diffusion optical fiber 17. Pulsed laser light from the laser resonator 15 L ₁₁ is relatively lower peak for average power output is low, the diffusion optical fiber 17 is not damaged.

The pulse laser beam L ₁₁ is transmitted while being repeatedly reflected inside the optical fiber 17, and is emitted from the other end as a pulse laser beam L ₁₂ having a certain spread angle. The pulse laser beam L ₁₂ emitted from the diffusion optical fiber 17 is converted into a substantially parallel light beam by the second lens 20. However, since the light is repeatedly reflected inside the diffusing optical fiber 17, this light beam is a laser beam having a low spatial coherence and a large divergence angle indicating directivity unlike ordinary laser light. Moreover, due to also repeated receives reflected many times inside the diffusion optical fiber 17, the spatial intensity distribution of the pulse laser beam L ₁₂ is uniform.

The pulsed laser light L _1, after being bent by the second reflecting mirror 21, is transmitted to the optical amplification amplifier 16, the peak output is amplified to a very high pulse laser beam, before amplification pulsed laser beam since L ₁₂ is moderately divergent, the pulse laser light L ₂ of the amplified also a laser light moderately divergent. The pulse laser light L ₁₂ before amplification because the intensity distribution is uniform, the pulse laser beam L ₂ is also intensity distribution after amplification is uniform. That is, the Q-switched laser oscillator 10b is a pulsed laser beam having a uniform spatial intensity distribution, a low spatial coherence, and a large divergence angle indicating directivity as compared with a normal Q-switched laser oscillator. L ₂ is emitted.

As described above, according to the present embodiment, the diffusion optical fiber 17 is inserted between the laser resonator 15 and the optical amplification amplifier 16, so that a spatial intensity distribution is generated from the Q switch type laser oscillator 10b. uniform, coherence is low, the pulse laser beam L ₂ is greater spread angle representing the directivity is emitted.

Pulsed laser light L ₂ of the present embodiment also, high spatial coherence, normal in comparison with the pulse laser beam spread angle representing the directivity is small, the current when condensed by using the same condensing optical system The diameter of the light beam increases. That is, even when introduced into a transmission optical fiber (not shown) the pulse laser light L _2, not converged finely within the optical fiber. Further, since the intensity distribution of the pulse laser beam L ₂ is uniform, no local intensity peak at the introduction portion of the transmission optical fiber.

  Therefore, if this Q-switch type laser oscillator 10b is used as a light source, high peak output pulsed laser light can be transmitted through the optical fiber without damaging the transmission optical fiber.

[Third Embodiment (FIG. 3)]
Next, a third embodiment of the present invention will be described. FIG. 3 is a block diagram showing the pulse laser oscillator according to the present embodiment.

  This pulse laser oscillator 10c is a Q-switch type laser oscillator, and the same laser resonator 15 as that of the second embodiment and a first concave lens 22 for sequentially introducing the pulse laser beam L11 emitted from the laser resonator 15 are used. An optical fiber plate (hereinafter referred to as FOP) 23, a condenser lens 24, a second concave lens 25, and an optical amplification amplifier 16 are provided. The FOP 23 is an optical element in which small cylindrical kaleidoscopes are arranged on a plane in a compound eye shape. In each kaleidoscope portion, for example, 1 to 10 reflections are performed.

Next, the operation of the Q switch type laser oscillator 10c will be described. From the laser resonator 15, a short time width, the pulse laser light L ₁₁ is large ratio of peak output to average power is emitted. The pulse laser beam L ₁₁ is enlarged by the concave lens 22 to a size that matches the aperture of the FOP 23 and is introduced into the FOP 23 from one end thereof. The introduced pulse laser beam L ₁₁ is transmitted while being locally reflected inside the FOP 23, and is emitted from the other end as a pulse laser beam L ₁₂ having a certain spread angle. Pulsed laser light L ₁₂ emitted from FOP23 by condenser lens 24 and a concave lens 25, is converted into substantially parallel light flux having a diameter that matches the diameter of the optical amplification amplifier 16.

However, since it has been locally and repeatedly reflected inside the FOP 23, this light beam is a laser beam having a low spatial coherence and a large divergence angle representing directivity, unlike ordinary laser light. Also, since receiving the locally repeatedly reflected inside the FOP23, spatial intensity distribution of the pulse laser beam L ₁₂ is uniform. The pulse laser beam L ₁₂ is transmitted to the optical amplification amplifier 16, the peak output is amplified to a very high pulse laser beam, the pulse laser light L ₁₁ before the amplification is appropriately diverged, after amplification pulsed laser light L ₁₂ of also serving as a laser light moderately divergent divergent. The pulse laser light L ₁₁ before the amplification is the intensity distribution is uniform, the pulse laser light L ₁₂ after the amplification also intensity distribution is uniform. That is, the Q-switched laser oscillator 10c is a pulsed laser beam having a uniform spatial intensity distribution, a low spatial coherence, and a large divergence angle representing directivity as compared with a normal Q-switched laser oscillator. L ₂ is emitted.

According to the present embodiment, by inserting the FOP 23 between the laser resonator 15 and the optical amplification amplifier 16, the spatial intensity distribution from the Q-switched laser oscillator 10c is uniform, and the spatial coherence is low. and spread angle representing the directivity is large pulse laser beam L ₂ is emitted. Such a pulse laser beam L ₂ is a high spatial coherence, normal in comparison with the laser beam divergence angle representing the directivity is small, when condensed using the same condensing optical system condensing light beam The diameter increases. That is, even when the introduction of the pulse laser light L ₂ to a transmission optical fiber, not converged finely within the optical fiber. Further, since the spatial intensity distribution of the pulse laser beam L ₂ is uniform, the optical fiber introduction part no local intensity peak. Therefore, if this Q-switch type laser oscillator 10c is used as a light source, pulse laser light having a high peak output can be transmitted through the optical fiber without damaging the transmission optical fiber.

[Fourth Embodiment (FIG. 4)]
FIG. 4 is a block diagram showing a pulse laser oscillator according to the fourth embodiment of the present invention.

  This pulse laser oscillator 10d is a Q-switch type laser oscillator, and uses one kaleidoscope 26 instead of the FOP 23 in the third embodiment. The kaleidoscope 26 is an optical element having an inner wall surface formed of a reflecting mirror having a prismatic shape or a cylindrical shape. In the kaleidoscope 26, for example, 1 to 10 reflections are performed. For other configurations, the same reference numerals as those in FIG. 3 are shown in FIG.

Next, the operation of the Q-switch type laser oscillator 10d will be described. From the laser resonator 15, a short time width, the pulse laser light L ₁₁ is large ratio of peak output to average power is emitted. The pulse laser beam L ₁₁ is enlarged by the concave lens 22 to a size that matches the aperture of the kaleidoscope 26 and introduced into the kaleidoscope 26 from one end thereof. Pulsed laser light L ₁₁ that is introduced is transmitted while being reflected locally within the kaleidoscope 26, it is emitted as pulsed laser light L ₁₂ having an angle of divergence in the other end. The pulsed laser light L ₁₂ emitted from the kaleidoscope 26 is converted into a substantially parallel light beam having a diameter that matches the aperture of the optical amplification amplifier 16 by the condenser lens 24 and the concave lens 25.

However, since the local repetitive reflection is received inside the kaleidoscope 26, this light beam is a laser beam having a low spatial coherence and a large divergence angle representing directivity, unlike ordinary laser light. Also, since receiving the locally repeatedly reflected within the kaleidoscope 26, the spatial intensity distribution of the pulse laser beam L ₁₂ is uniform. The pulse laser beam L ₁₂ is transmitted to the optical amplification amplifier 16, the peak output is amplified to a very high pulse laser beam, the pulse laser beam L11 before the amplification is appropriately diverged, after amplification pulsed laser light L ₁₂ is also a laser light moderately divergent divergent. The pulse laser light L ₁₁ before the amplification is the intensity distribution is uniform, the pulse laser light L ₁₂ after the amplification also intensity distribution is uniform. That is, the Q-switched laser oscillator 10c is a pulsed laser beam having a uniform spatial intensity distribution, a low spatial coherence, and a large divergence angle representing directivity as compared with a normal Q-switched laser oscillator. L ₂ is emitted.

According to the present embodiment, by inserting the kaleidoscope 26 between the laser resonator 15 and the optical amplification amplifier 16, the spatial intensity distribution from the Q-switch type laser oscillator 10c is uniform and spatial. coherence is low and the pulse laser beam L ₂ is greater spread angle representing the directivity is emitted. Such a pulsed laser beam L2 has a spatial light coherence and a diameter of the collected beam when condensed using the same condensing optical system as compared with a normal laser beam having a small divergence angle representing directivity. Will grow. That is, even when the introduction of the pulse laser light L ₂ to a transmission optical fiber, not converged finely within the optical fiber. Further, since the spatial intensity distribution of the pulse laser beam L ₂ is uniform, the optical fiber introduction part no local intensity peak. Therefore, if this Q-switch type laser oscillator 10c is used as a light source, pulse laser light having a high peak output can be transmitted through the optical fiber without damaging the transmission optical fiber.

[Fifth Embodiment (FIG. 5)]
FIG. 5 is a block diagram showing a pulse laser oscillator according to a fifth embodiment of the present invention.

  This pulse laser oscillator 10e is a Q-switch type laser oscillator, and uses a diffusion light transmission plate 27 instead of the FOP 23 in the third embodiment. For example, an optical element such as frosted glass having a light transmittance of 20 to 70% is applied to the light transmission plate 27 for diffusion, and a laser beam with high directivity can be diffused appropriately.

Next, the operation of the Q-switch type laser oscillator 10e will be described. From the laser resonator 15, a short time width, the pulse laser light L ₁₁ is large ratio of peak output to average power is emitted. The pulse laser beam L ₁₁ is enlarged by the concave lens 22 to a size that matches the aperture of the diffusion light transmission plate 27 and introduced into the diffusion light transmission plate 27 from one end thereof. Pulsed laser light L ₁₁ that is introduced is transmitted while being locally reflected inside the diffused-light transmitting plate 27, it is emitted as pulsed laser light L ₁₂ having an angle of divergence in the other end. The pulsed laser light L ₁₂ emitted from the diffusion light transmitting plate 27 is converted by the condenser lens 24 and the concave lens 25 into a substantially parallel light beam having a diameter that matches the aperture of the optical amplification amplifier 16.

However, since the light beam is locally and repeatedly reflected inside the diffusing light transmitting plate 27, this light beam is different from normal laser light, and has a low spatial coherence and a large spread angle representing directivity. . Further, in order to appropriately diffused within the diffuse light transmitting plate 27, the spatial intensity distribution of the pulse laser beam L ₁₂ is uniform. The pulse laser beam L ₁₂ is transmitted to the optical amplification amplifier 16, the peak output is amplified to a very high pulse laser beam, the pulse laser light L ₁₁ before the amplification is appropriately diverged, after amplification pulsed laser light L ₁₂ of also serving as a laser light moderately divergent divergent. The pulse laser light L ₁₁ before the amplification is the intensity distribution is uniform, the pulse laser light L ₁₂ after the amplification also intensity distribution is uniform. That is, the Q-switched laser oscillator 10c is a pulsed laser beam having a uniform spatial intensity distribution, a low spatial coherence, and a large divergence angle representing directivity as compared with a normal Q-switched laser oscillator. L ₂ is emitted.

According to the present embodiment, by inserting the diffusion light transmission plate 27 between the laser resonator 15 and the optical amplification amplifier 16, the spatial intensity distribution from the Q-switch type laser oscillator 10c is uniform, and the spatial coherence is low and the pulse laser beam L ₂ is greater spread angle representing the directivity is emitted. Such a pulse laser beam L ₂ is a high spatial coherence, normal in comparison with the laser beam divergence angle representing the directivity is small, when condensed using the same condensing optical system condensing light beam The diameter increases. That is, even when the introduction of the pulse laser light L ₂ to a transmission optical fiber, not converged finely within the optical fiber. Further, since the spatial intensity distribution of the pulse laser beam L ₂ is uniform, the optical fiber introduction part no local intensity peak. Therefore, if this Q-switch type laser oscillator 10c is used as a light source, pulse laser light having a high peak output can be transmitted through the optical fiber without damaging the transmission optical fiber.

[Sixth Embodiment (FIG. 6)]
FIG. 6 is a block diagram showing a pulse laser oscillator according to a sixth embodiment of the present invention.

This pulse laser oscillator 10f is a Q-switch type laser oscillator, and uses a microlens array 27a instead of the FOP 23 and the condenser lens 24 of the third embodiment. The micro lens array 27a is an optical element in which small condensing lenses 27a ₁ ... Obtained by dividing the condensing lens 24 shown in the third embodiment into 2 to 36 are arranged on a plane compound-eye.

Next, the operation of the Q-switch type laser oscillator 10f will be described. From the laser resonator 15, a short time width, the pulse laser light L ₁₁ is large ratio of peak output to average power is emitted. The pulse laser beam L ₁₁ is introduced from one end thereof is expanded to a size that matches the diameter of the microlens array 27a by a concave lens 22 to the microlens array 27a. Pulsed laser light L ₁₁ that is introduced is transmitted while being locally reflected inside the microlens array 27a, and is emitted as pulsed laser light L ₁₂ having an angle of divergence in the other end. Pulsed laser light L ₁₂ emitted from the microlens array 27a by a condenser lens 24 and a concave lens 25, is converted into substantially parallel light flux having a diameter that matches the diameter of the optical amplification amplifier 16.

However, since the light passes through the microlens array 27a, this light beam is a laser beam having a low spatial coherence and a large divergence angle representing directivity, unlike ordinary laser light. Also, since receiving the locally repeatedly reflected inside the microlens array 27a, the spatial intensity distribution of the pulse laser beam L ₁₂ is uniform. The pulse laser beam L ₁₂ is transmitted to the optical amplification amplifier 16, the peak output is amplified to a very high pulse laser beam, the pulse laser light L ₁₁ before the amplification is appropriately diverged, after amplification pulsed laser light L ₁₂ of also serving as a laser light moderately divergent divergent. The pulse laser light L ₁₁ before the amplification is the intensity distribution is uniform, the pulse laser light L ₁₂ after the amplification also intensity distribution is uniform. That is, from this Q-switched laser oscillator 10f, compared with a normal Q-switched laser oscillator, a pulse laser beam having a uniform spatial intensity distribution, low spatial coherence, and a large divergence angle representing directivity. L ₂ is emitted.

According to the present embodiment, by inserting the microlens array 27a between the laser resonator 15 and the optical amplification amplifier 16, the spatial intensity distribution from the Q-switch type laser oscillator 10f is uniform and spatial. coherence is low and the pulse laser beam L ₂ is greater spread angle representing the directivity is emitted. Such a pulse laser beam L ₂ is a high spatial coherence, normal in comparison with the laser beam divergence angle representing the directivity is small, when condensed using the same condensing optical system condensing light beam The diameter increases. That is, even when the introduction of the pulse laser light L ₂ to a transmission optical fiber, not converged finely within the optical fiber. Further, since the spatial intensity distribution of the pulse laser beam L ₂ is uniform, the optical fiber introduction part no local intensity peak. Therefore, if this Q-switch type laser oscillator 10f is used as a light source, high peak output pulsed laser light can be transmitted through the optical fiber without damaging the transmission optical fiber.

[Seventh Embodiment (FIG. 7)]
FIG. 7 is a configuration diagram illustrating an optical fiber light guide device according to a seventh embodiment of the present invention.

The optical fiber light guide device 28a is, for example, a conventional optical fiber light guide device for guiding the transmission optical fiber 32 to the pulse laser light L ₀ from the pulsed laser oscillator, along the passing direction of the pulsed laser light L The concave lens 29 and the FOP 30 are arranged in order, and a condensing lens 31 as a condensing optical system for condensing the pulsed laser light L01 emitted from the FOP 30 is provided.

Pulse laser beam L ₀ incident on the optical fiber light guide device 28a is a peak power high pulse laser beam, for example, pulsed laser light generated from the Q-switched YAG laser oscillator or the second harmonic or the like It is. The FOP 30 is an optical element in which small cylindrical kaleidoscopes are arranged on a plane in a compound eye shape in substantially the same manner as described above.

Next, the operation of the optical fiber light guide device 28a will be described. The pulse laser beam L ₀ having a high peak output is expanded to a size that matches the aperture of the FOP 30 by the concave lens 29 and introduced into the FOP 30 from one end thereof. The pulse laser beam L ₀ is transmitted while being locally reflected inside the FOP 30, and is emitted as a pulse laser beam L ₀₁ having a certain spread angle from the other end. Since the pulsed laser beam L ₀₁ emitted from the FOP 30 is repeatedly reflected locally within the FOP 30, the spatial coherence is low. Also, since receiving the locally repeatedly reflected within the FOP 30, the spatial intensity distribution of the pulse laser beam L ₀₁ is uniform. The pulsed laser light L ₀₁ emitted from the FOP 30 is condensed by the condenser lens 31, and the condensed pulsed laser light L ₀₂ is introduced into the transmission optical fiber 32. The pulsed laser light L ₀₂ introduced into the transmission optical fiber 32 is reflected and converged at the boundary surface between the concave core and the clad. However, since the spatial coherence is low, the spatial coherence is low. It does not converge finely like a high normal laser beam. Further, since the spatial intensity distribution is uniform, there is no local intensity peak at the introduction portion of the transmission optical fiber 32.

According to the present embodiment, the pulsed laser light L ₀ having high spatial coherence is introduced into the transmission optical fiber 32 after the spatial coherence is lowered through the FOP 30, so that the introduced pulsed laser light L ₀₂ is The optical fiber 32 for transmission does not converge finely, and the optical fiber 32 for transmission is not damaged. Moreover, since the introduced transmission optical fiber 32 after homogenizing the spatial intensity distribution throughout the FOP 30, pulse laser light L ₀₂ at the introduction portion of the transmission optical fiber 32 has no local intensity peak, transmission The optical fiber 32 is not damaged. Therefore, if this optical fiber light guide device 28a is used, pulse laser light having a high peak output can be transmitted through the optical fiber without damaging the transmission optical fiber.

[Eighth Embodiment (FIG. 8)]
FIG. 8 is a configuration diagram illustrating an optical fiber light guide device according to an eighth embodiment of the present invention.

  This optical fiber light guide device 28b uses a kaleidoscope 33 instead of the FOP of the seventh embodiment. The kaleidoscope 33 is an optical element having an inner wall surface constituted by a reflecting mirror having a prismatic shape or a cylindrical shape, as described above. The other components in FIG. 8 that are the same as those in the seventh embodiment are denoted by the same reference numerals as those in FIG.

Next, the operation of the pulse laser light guide device 28b will be described. The pulse laser beam L ₀ having a high peak output is enlarged to a size suitable for the aperture of the kaleidoscope 33 by the concave lens 29 and introduced into the kaleidoscope 33 from one end thereof. The pulse laser beam L ₀ is transmitted while being locally reflected inside the kaleidoscope 33, and is emitted as a pulse laser beam L ₀₁ having a certain spread angle from the other end. Since the pulse laser beam L ₀₁ emitted from the kaleidoscope 33 is repeatedly reflected locally within the kaleidoscope 33, the spatial coherence is low. Further, since the reflection repeatedly received locally inside the kaleidoscope 33, the spatial intensity distribution of the pulse laser beam _L01 is made uniform. The pulse laser beam L ₀₁ emitted from the kaleidoscope 33 is collected by the condenser lens 31, and the collected pulse laser beam L 02 is introduced into the transmission optical fiber 32. The pulsed laser light L ₀₂ introduced into the transmission optical fiber 32 is reflected and converged at the boundary surface between the concave core and the clad. However, since the spatial coherence is low, the spatial coherence is low. It does not converge finely like a high normal laser beam. Further, since the spatial intensity distribution is uniform, there is no local intensity peak at the introduction portion of the transmission optical fiber 32.

According to the present embodiment, the pulsed laser light L ₀ having high spatial coherence is introduced into the transmission optical fiber 32 after the spatial coherence is lowered through the kaleidoscope 33, so the introduced pulsed laser light. L ₀₂ does not converge finely inside the transmission optical fiber 32 and does not damage the transmission optical fiber 32. Further, since the spatial intensity distribution is made uniform through the kaleidoscope 33 and then introduced into the transmission optical fiber 32, the pulse laser beam _L02 has a local intensity peak at the introduction portion of the transmission optical fiber 32. Therefore, the transmission optical fiber 32 is not damaged. Therefore, by using this optical fiber light guide device 28b, it is possible to transmit high-peak output pulsed laser light through the optical fiber without damaging the transmission optical fiber.

[Ninth Embodiment (FIG. 9)]
FIG. 9 is a configuration diagram illustrating an optical fiber light guide device according to a ninth embodiment of the present invention.

  In this optical fiber light guide device 28c, a diffusion light transmission plate 34 is applied instead of the FOP of the seventh embodiment. Similarly to the light transmission plate 34 for diffusion, an optical element such as frosted glass is applied, and pulse laser light having high directivity can be diffused appropriately. In FIG. 9, the same reference numerals as those in FIG. 7 are given to the same parts as those in the seventh embodiment in FIG.

Next, the operation of the pulse laser light guide device 28c will be described. The pulsed laser light L ₀ having a high peak output is enlarged by the concave lens 29 to a size suitable for the aperture of the diffusion light transmission plate 34 and introduced into the diffusion light transmission plate 34 from one end thereof. The pulse laser beam L ₀ is transmitted while being locally reflected inside the diffusion light transmission plate 34, and is emitted as a pulse laser beam L ₀₁ having a certain spread angle from the other end. Since the pulsed laser light L ₀₁ emitted from the diffusion light transmission plate 34 is appropriately diffused inside the diffusion light transmission plate 34, the spatial coherence is low. Further, since the reflection is locally and repeatedly reflected inside the diffusion light transmission plate 34, the spatial intensity distribution of the pulse laser beam _L01 is made uniform. The pulsed laser light L ₀₁ emitted from the diffusion light transmitting plate 34 is condensed by the condenser lens 31, and the condensed pulsed laser light L ₀₂ is introduced into the transmission optical fiber 32. The pulsed laser light L ₀₂ introduced into the transmission optical fiber 32 is reflected and converged at the boundary surface between the concave core and the clad. However, since the spatial coherence is low, the spatial coherence is low. It does not converge finely like a high normal laser beam. Further, since the spatial intensity distribution is uniform, there is no local intensity peak at the introduction portion of the transmission optical fiber 32.

According to the present embodiment, the pulse laser beam L ₀ with high spatial coherence is introduced into the transmission optical fiber 32 after the spatial coherence is lowered through the diffusion light transmission plate 34, so that the introduced pulse The laser beam L ₀₂ does not converge finely inside the transmission optical fiber 32 and does not damage the transmission optical fiber 32. In addition, since the spatial intensity distribution is made uniform through the diffusion light transmitting plate 34 and then introduced into the transmission optical fiber 32, the pulse laser beam _L02 has a local intensity peak at the introduction portion of the transmission optical fiber 32. The transmission optical fiber 32 is not damaged. Therefore, if this optical fiber light guide device 28c is used, pulse laser light having a high peak output can be transmitted through the optical fiber without damaging the transmission optical fiber.

[Tenth Embodiment (FIG. 10)]
FIG. 10 is a configuration diagram illustrating an optical fiber light guide device according to a tenth embodiment of the present invention.

  In this optical fiber light guide device 28d, a microlens array 35 is applied instead of the FOP of the seventh embodiment. The microlens array 35 is an optical element in which small condensing lenses are arranged on a plane in a compound eye shape as described above. Other components in FIG. 10 that are the same as in the seventh embodiment are given the same reference numerals as in FIG.

Next, the operation of the pulse laser light guide device 28d will be described. The pulse laser beam L ₀ having a high peak output is enlarged by the concave lens 29 to a size suitable for the aperture of the microlens array 35 and introduced into the microlens array 35 from one end thereof. The pulse laser beam L ₀ is transmitted while being locally reflected inside the microlens array 35, and is emitted as a pulse laser beam L ₀₁ having a certain spread angle from the other end. Since the pulsed laser light L ₀₁ emitted from the microlens array 35 is moderately diffused inside the microlens array 35, the spatial coherence is low. Further, since the microlens array 350 has passed, the spatial intensity distribution of the pulsed laser light _L01 is made uniform. The pulsed laser light L ₀₁ emitted from the microlens array 35 is condensed by the condenser lens 31, and the condensed pulsed laser light L ₀₂ is introduced into the transmission optical fiber 32. The pulsed laser light L ₀₂ introduced into the transmission optical fiber 32 is reflected and converged at the boundary surface between the concave core and the clad. However, since the spatial coherence is low, the spatial coherence is low. It does not converge finely like a high normal laser beam. Further, since the spatial intensity distribution is uniform, there is no local intensity peak at the introduction portion of the transmission optical fiber 32.

According to the present embodiment, the pulsed laser light L ₀ with high spatial coherence is introduced into the transmission optical fiber 32 after the spatial coherence is lowered through the microlens array 35, so the introduced pulsed laser light. L ₀₂ does not converge finely inside the transmission optical fiber 32 and does not damage the transmission optical fiber 32. Further, since the spatial intensity distribution is made uniform through the microlens array 35 and then introduced into the transmission optical fiber 32, the pulse laser beam L02 does not have a local intensity peak at the introduction portion of the transmission optical fiber 32. The transmission optical fiber 32 is not damaged. Therefore, if this optical fiber light guide device 28d is used, pulse laser light having a high peak output can be transmitted through the optical fiber without damaging the transmission optical fiber.

[Eleventh Embodiment (FIG. 11)]
Next, a first embodiment of the present invention will be described. FIG. 11A is a cross-sectional view showing the entire transmission optical fiber according to the present embodiment. FIGS. 11B and 11C are the XX line and the YY line in FIG. It is sectional drawing.

  The transmission optical fiber 36 is formed of a core 37 of a core part and a clad 38 covering the core. The core 37 is made of a material such as quartz, and the refractive index distribution is a step index type. The core 37 of the transmission optical fiber 36 has a prismatic shape at a constant length portion (C portion) on one end side, and a cylindrical shape at the other portion (D portion).

  The operation of this transmission optical fiber 36 will be described. When a pulse laser beam L having a high peak output is collected from a normal pulse laser oscillator (not shown) and introduced into the transmission optical fiber 36 from one end where the core 37 has a prismatic shape, the pulse laser beam L is First, reflection is received at the boundary surface between the outer peripheral surface of the prismatic core 37 and the surrounding cladding 38. Since this boundary surface has a prismatic shape and is a flat surface, the reflected light is dispersed and does not converge finely. Then, the pulse laser beam L is transmitted while being repeatedly reflected inside the prism-shaped core 37 and reaches the inside of the cylindrical core 37. However, the spatial coherence of the pulsed laser light L is low because it is repeatedly reflected inside the prism-shaped core 37.

  Next, the pulse laser beam L is reflected and converged inside the cylindrical core 37 because the boundary surface between the outer peripheral surface of the core 37 and the surrounding cladding 38 is a concave mirror-shaped arc surface. Since the spatial coherence is low, the laser beam does not converge as finely as an ordinary laser beam having a high spatial coherence.

  According to this embodiment, since the end of the core 37 of the transmission optical fiber 36 has a prismatic shape, even if the pulse laser light L is guided to the transmission optical fiber 36, the pulse laser light L is The optical fiber 36 for transmission does not converge finely and does not damage the optical fiber. Therefore, if this transmission optical fiber 36 is used, a pulse laser beam having a high peak output can be transmitted through the optical fiber without damaging the optical fiber itself.

[Twelfth Embodiment (FIG. 12)]
Next, a twelfth embodiment of the present invention will be described.

  FIG. 12 is a configuration diagram showing the optical fiber transmission type laser apparatus according to the present embodiment.

The optical fiber transmission type laser system 39a includes a pulse laser oscillator 10a shown in the first embodiment, a condenser lens 40 as a condensing optical system for converging the pulse laser light L ₂ from the pulse laser oscillator 10a It is configured to include an optical fiber 41 for transmitting a pulsed laser beam L ₂ condensed. For the transmission optical fiber 41, for example, a step index type optical fiber having a quartz core is used.

In the optical fiber transmission type laser apparatus having such a configuration, the pulse laser oscillator 10a has a high peak output pulse having a low spatial coherence and a large divergence angle representing directivity by the action shown in the first embodiment. the laser beam _{L 2} is emitted. This pulse laser beam L ₂ is introduced into the transmission optical fiber 41 is condensed by the condenser lens 40, it is converged by receiving reflected at the boundary surface between the core and the cladding in which the concave, Since the spatial coherence is low, it does not converge finely.

According to this embodiment, since using pulsed laser oscillator 10a to the surface 11a of the rear mirror 11 of the laser resonator 15 and the sand surface as the light source, pulsed laser light L ₂ is not converged finely within the transmission optical fiber 41 And does not damage the optical fiber. Therefore, if this optical fiber type laser device 39a is used, a pulse laser beam having a high peak output can be transmitted through the optical fiber without damaging the transmission optical fiber 41.

[Thirteenth Embodiment (FIG. 13)]
FIG. 13 is a block diagram showing an optical fiber transmission laser device according to a thirteenth embodiment of the present invention.

The optical fiber transmission type laser system 39b includes a pulse laser oscillator 10b shown in the second embodiment, a condenser lens 40 as a condensing optical system for converging the pulse laser light L ₂ from the pulse laser oscillator 10b It is configured to include an optical fiber 41 for transmitting a pulsed laser beam L ₂ condensed. For the transmission optical fiber 41, for example, a step index type optical fiber having a quartz core is used.

In the optical fiber transmission type laser apparatus having such a configuration, the pulse laser oscillator 10b has a high peak output pulse with a low spatial coherence and a large divergence angle representing directivity by the action shown in the first embodiment. the laser beam _{L 2} is emitted. This pulse laser beam L ₂ is introduced into the transmission optical fiber 41 is condensed by the condenser lens 40, it is converged by receiving reflected at the boundary surface between the core and the cladding in which the concave, Since the spatial coherence is low, it does not converge finely. Further, since the spatial intensity distribution is uniform, there is no local intensity peak at the introduction portion of the transmission optical fiber 41.

Also according to this embodiment, the pulse laser beam L ₂ is not converged finely within the transmission optical fiber 41, also does not have a local intensity peak at the introduction portion of the transmission optical fiber 41, not to damage the optical fiber . Therefore, by using this optical fiber type laser device 39b, it is possible to transmit a high peak output pulse laser beam through an optical fiber without damaging the transmission optical fiber 41.

[Fourteenth Embodiment (FIG. 14)]
FIG. 14 is a block diagram showing an optical fiber transmission laser device according to a fourteenth embodiment of the present invention.

The optical fiber transmission type laser system 39c includes a pulse laser oscillator 10c shown in the second embodiment, a condenser lens 40 as a condensing optical system for converging the pulse laser light L ₂ from the pulse laser oscillator 10c It is configured to include an optical fiber 41 for transmitting a pulsed laser beam L ₂ condensed. For the transmission optical fiber 41, for example, a step index type optical fiber having a quartz core is used.

In the optical fiber transmission type laser device having such a configuration, the pulse laser oscillator 10c has a high peak output pulse having a low spatial coherence and a large divergence angle representing directivity by the action shown in the first embodiment. the laser beam _{L 2} is emitted. This pulse laser beam L ₂ is introduced into the transmission optical fiber 41 is condensed by the condenser lens 40, it is converged by receiving reflected at the boundary surface between the core and the cladding in which the concave, Since the spatial coherence is low, it does not converge finely. Further, since the spatial intensity distribution is uniform, there is no local intensity peak at the introduction portion of the transmission optical fiber 41.

Also according to this embodiment, the pulse laser beam L ₂ is not converged finely within the transmission optical fiber 41, also does not have a local intensity peak at the introduction portion of the transmission optical fiber 41, not to damage the optical fiber . Therefore, if this optical fiber type laser device 39c is used, a pulse laser beam having a high peak output can be transmitted through the optical fiber without damaging the transmission optical fiber 41.

[Fifteenth embodiment (FIG. 15)]
FIG. 15 is a block diagram showing an optical fiber transmission laser apparatus according to the fifteenth embodiment of the present invention.

The optical fiber transmission type laser system 39d includes a pulse laser oscillator 10d shown in the second embodiment, a condenser lens 40 as a condensing optical system for converging the pulse laser light L ₂ from the pulse laser oscillator 10d It is configured to include an optical fiber 41 for transmitting a pulsed laser beam L ₂ condensed. For the transmission optical fiber 41, for example, a step index type optical fiber having a quartz core is used.

In the optical fiber transmission type laser apparatus having such a configuration, the pulse laser oscillator 10d has a high peak output pulse having a low spatial coherence and a large divergence angle representing directivity by the action shown in the first embodiment. the laser beam _{L 2} is emitted. This pulse laser beam L ₂ is introduced into the transmission optical fiber 41 is condensed by the condenser lens 40, it is converged by receiving reflected at the boundary surface between the core and the cladding in which the concave, Since the spatial coherence is low, it does not converge finely. Further, since the spatial intensity distribution is uniform, there is no local intensity peak at the introduction portion of the transmission optical fiber 41.

Also according to this embodiment, the pulse laser beam L ₂ is not converged finely within the transmission optical fiber 41, also does not have a local intensity peak at the introduction portion of the transmission optical fiber 41, not to damage the optical fiber . Therefore, if this optical fiber type laser device 39d is used, a pulse laser beam having a high peak output can be transmitted through the optical fiber without damaging the transmission optical fiber 41.

[Sixteenth Embodiment (FIG. 16)]
FIG. 16 is a block diagram showing an optical fiber transmission type laser apparatus according to a sixteenth embodiment of the present invention.

The optical fiber transmission type laser device 39e includes a pulse laser oscillator 10e shown in the second embodiment, a condenser lens 40 as a condensing optical system for converging the pulse laser light L ₂ from the pulse laser oscillator 10e It is configured to include an optical fiber 41 for transmitting a pulsed laser beam L ₂ condensed. For the transmission optical fiber 41, for example, a step index type optical fiber having a quartz core is used.

In the optical fiber transmission type laser apparatus having such a configuration, the pulse laser oscillator 10e has a high peak output pulse with a low spatial coherence and a large divergence angle representing directivity by the action shown in the first embodiment. the laser beam _{L 2} is emitted. This pulse laser beam L ₂ is introduced into the transmission optical fiber 41 is condensed by the condenser lens 40, it is converged by receiving reflected at the boundary surface between the core and the cladding in which the concave, Since the spatial coherence is low, it does not converge finely. Further, since the spatial intensity distribution is uniform, there is no local intensity peak at the introduction portion of the transmission optical fiber 41.

Also according to this embodiment, the pulse laser beam L ₂ is not converged finely within the transmission optical fiber 41, also does not have a local intensity peak at the introduction portion of the transmission optical fiber 41, not to damage the optical fiber . Therefore, if this optical fiber type laser device 39e is used, a pulse laser beam having a high peak output can be transmitted through the optical fiber without damaging the transmission optical fiber 41.

[Seventeenth Embodiment (FIG. 17)]
FIG. 17 is a block diagram showing an optical fiber transmission laser device according to a seventeenth embodiment of the present invention.

The optical fiber transmission type laser device 39f includes a pulse laser oscillator 10f shown in the second embodiment, a condenser lens 40 as a condensing optical system for converging the pulse laser light L ₂ from the pulse laser oscillator 10f It is configured to include an optical fiber 41 for transmitting a pulsed laser beam L ₂ condensed. For the transmission optical fiber 41, for example, a step index type optical fiber having a quartz core is used.

In the optical fiber transmission type laser apparatus having such a configuration, the pulse laser oscillator 10f has a high peak output pulse having a low spatial coherence and a large divergence angle representing directivity by the action shown in the first embodiment. the laser beam _{L 2} is emitted. This pulse laser beam L ₂ is introduced into the transmission optical fiber 41 is condensed by the condenser lens 40, it is converged by receiving reflected at the boundary surface between the core and the cladding in which the concave, Since the spatial coherence is low, it does not converge finely. Further, since the spatial intensity distribution is uniform, there is no local intensity peak at the introduction portion of the transmission optical fiber 41.

Also according to this embodiment, the pulse laser beam L ₂ is not converged finely within the transmission optical fiber 41, also does not have a local intensity peak at the introduction portion of the transmission optical fiber 41, not to damage the optical fiber . Therefore, if this optical fiber type laser device 39f is used, a pulse laser beam having a high peak output can be transmitted through the optical fiber without damaging the transmission optical fiber 41.

[Eighteenth Embodiment (FIG. 18)]
FIG. 18 is a block diagram showing an optical fiber transmission laser device according to an eighteenth embodiment of the present invention.

  The optical fiber transmission type laser device 42 a is configured to include the pulse laser oscillator 10, the optical fiber light guide device 28 a shown in the seventh embodiment, and the transmission optical fiber 41. As the pulse laser oscillator 10, a Q-switch type YAG laser oscillator, a Q-switch type SH-YAG laser oscillator, or the like is applied. The pulse laser oscillators 10a to 10f shown in the first to sixth embodiments can also be applied. For the transmission optical fiber 41, for example, a step index type optical fiber having a quartz core is used.

Next, the operation of the optical fiber transmission type laser device 42a will be described. From the pulse laser oscillator 10, a pulse laser beam L ₂ having high peak power is emitted. This pulse laser beam L ₂ is introduced into the transmission optical fiber 41 become pulsed laser light L _3, which is condensed by an optical fiber light guide device 28a, by the action described in the seventh embodiment, the transmission The optical fiber 41 does not converge finely and does not have a local intensity peak at the introduction portion of the transmission optical fiber 41.

According to this embodiment, since the application of the optical fiber light guide device 28a inserting the FOP 30, pulse laser light L ₃ is not converged finely within the transmission optical fiber 41, also the introduction of the transmission optical fiber 41 There is no local intensity peak at the part, and the optical fiber is not damaged. Therefore, if this optical fiber type laser device is used, pulse laser light having a high peak output can be transmitted by the optical fiber without damaging the optical fiber.

[Nineteenth Embodiment (FIG. 19)]
FIG. 19 is a configuration diagram showing an optical fiber transmission laser device according to a nineteenth embodiment of the present invention.

  The optical fiber transmission type laser device 42b includes the pulse laser oscillator 10, the optical fiber light guide device 28b shown in the eighth embodiment, and the transmission optical fiber 41. As the pulse laser oscillator 10, a Q-switch type YAG laser oscillator, a Q-switch type SH-YAG laser oscillator, or the like is applied. The pulse laser oscillators 10a to 10f shown in the first to sixth embodiments can also be applied. For the transmission optical fiber 41, for example, a step index type optical fiber having a quartz core is used.

Next, the operation of the optical fiber transmission type laser device 42b will be described. From the pulse laser oscillator 10, a pulse laser beam L ₂ having high peak power is emitted. This pulsed laser light L2 is introduced into the transmission optical fiber 41 become pulsed laser light L _3, which is condensed by an optical fiber light guide device 28b, by the effect described in the eighth embodiment, for transmission It does not converge finely inside the optical fiber 41 and does not have a local intensity peak at the introduction portion of the transmission optical fiber 41.

According to this embodiment, since the application of the optical fiber light guide device 28b inserting the kaleidoscope 33, pulse laser light L ₃ is not converged finely within the transmission optical fiber 41, also the transmission optical fiber 41 does not have a local intensity peak at the introduction portion and does not damage the optical fiber. Therefore, if this optical fiber type laser device is used, pulse laser light having a high peak output can be transmitted by the optical fiber without damaging the optical fiber.

[20th Embodiment (FIG. 20)]
FIG. 20 is a block diagram showing an optical fiber transmission laser apparatus according to the twentieth embodiment of the present invention.

  The optical fiber transmission type laser device 42c includes the pulse laser oscillator 10, the optical fiber light guide device 28c shown in the ninth embodiment, and the transmission optical fiber 41. As the pulse laser oscillator 10, a Q-switch type YAG laser oscillator, a Q-switch type SH-YAG laser oscillator, or the like is applied. The pulse laser oscillators 10a to 10f shown in the first to sixth embodiments can also be applied. For the transmission optical fiber 41, for example, a step index type optical fiber having a quartz core is used.

Next, the operation of the optical fiber transmission type laser device 42c will be described. From the pulse laser oscillator 10, a pulse laser beam L ₂ having high peak power is emitted. This pulse laser beam L ₂ is introduced into the transmission optical fiber 41 become pulsed laser light L _3, which is condensed by an optical fiber light guide device 28c, by the action described in the ninth embodiment, the transmission The optical fiber 41 does not converge finely and does not have a local intensity peak at the introduction portion of the transmission optical fiber 41.

According to this embodiment, since the application of the optical fiber light guide device 28c inserted the diffusion light transmitting plate 34, the pulse laser beam L ₃ is not converged finely within the transmission optical fiber 41, also for transmission There is no local intensity peak at the introduction portion of the optical fiber 41, and the optical fiber is not damaged. Therefore, if this optical fiber type laser device is used, pulse laser light having a high peak output can be transmitted by the optical fiber without damaging the optical fiber.

[Twenty-first embodiment (FIG. 21)]
FIG. 21 is a configuration diagram showing an optical fiber transmission laser device according to a twenty-first embodiment of the present invention.

  The optical fiber transmission type laser device 42d includes the pulse laser oscillator 10, the optical fiber light guide device 28d shown in the tenth embodiment, and the transmission optical fiber 41. As the pulse laser oscillator 10, a Q-switch type YAG laser oscillator, a Q-switch type SH-YAG laser oscillator, or the like is applied. The pulse laser oscillators 10a to 10f shown in the first to sixth embodiments can also be applied. For the transmission optical fiber 41, for example, a step index type optical fiber having a quartz core is used.

Next, the operation of the optical fiber transmission type laser device 42d will be described. From the pulse laser oscillator 10, a pulse laser beam L ₂ having high peak power is emitted. This pulse laser beam L ₂ is introduced into the transmission optical fiber 41 become pulsed laser light L _3, which is condensed by an optical fiber light guide device 28d, by the action described in the tenth embodiment, the transmission The optical fiber 41 does not converge finely and does not have a local intensity peak at the introduction portion of the transmission optical fiber 41.

According to this embodiment, since the application of the optical fiber light guide device 28d inserting the microlens array 35, a pulse laser beam L ₃ is not converged finely within the transmission optical fiber 41, also the transmission optical fiber 41 does not have a local intensity peak at the introduction portion and does not damage the optical fiber. Therefore, if this optical fiber type laser device is used, pulse laser light having a high peak output can be transmitted by the optical fiber without damaging the optical fiber.

The block diagram which shows the pulse laser oscillator by 1st Embodiment of this invention. The block diagram which shows the pulse laser oscillator by 2nd Embodiment of this invention. The block diagram which shows the pulse laser oscillator by 3rd Embodiment of this invention. The block diagram which shows the pulse laser oscillator by 4th Embodiment of this invention. The block diagram which shows the pulse laser oscillator by 5th Embodiment of this invention. The block diagram which shows the pulse laser oscillator by 6th Embodiment of this invention. The block diagram which shows the optical fiber light guide device by 7th Embodiment of this invention. The block diagram which shows the optical fiber light guide device by 8th Embodiment of this invention. The block diagram which shows the optical fiber light guide device by 9th Embodiment of this invention. The lineblock diagram showing the optical fiber light guide device by a 10th embodiment of the present invention. (A) is sectional drawing which shows the optical fiber light guide device by 11th Embodiment of this invention, (b), (c) is the XX line and XY line sectional drawing of (a), respectively. The block diagram which shows the optical fiber transmission type laser apparatus by 12th Embodiment of this invention. The block diagram which shows the optical fiber transmission type laser apparatus by 13th Embodiment of this invention. The block diagram which shows the optical fiber transmission type laser apparatus by 14th Embodiment of this invention. The block diagram which shows the optical fiber transmission type laser apparatus by 15th Embodiment of this invention. The block diagram which shows the optical fiber transmission type laser apparatus by 16th Embodiment of this invention. The block diagram which shows the optical fiber transmission type laser apparatus by 17th Embodiment of this invention. The block diagram which shows the optical fiber transmission type laser apparatus by 18th Embodiment of this invention. The block diagram which shows the optical fiber transmission type laser apparatus by 19th Embodiment of this invention. The block diagram which shows the optical fiber transmission type laser apparatus by 20th Embodiment of this invention. The block diagram which shows the optical fiber transmission type laser apparatus by 21st Embodiment of this invention. The figure which shows the prior art example which uses the optical fiber light guide device by imaging. The figure which shows the prior art example which uses a taper fiber.

Explanation of symbols

10, 10a, 10b, 10c, 10d, 10e, 10f Pulse laser oscillator 11 Rear mirror 11a Surface 12 Q switch 13 Oscillator 14 Output mirror 15 Laser resonator 16 Optical amplifier 17 Diffusing optical fiber 18 Reflecting mirror 19 Condensing lens 20 Second condensing lens 21 Reflecting mirror 23 Optical fiber plate (FOP)
24 condensing lens 25 second concave lens 26 kaleidoscope 27 diffusing light transmitting plate 27a micro lens array 27a1 condensing lenses 28a, 28b, 28c, 28d optical fiber light guide device 29 concave lens 30 FOP
31 condensing lens 32 transmission optical fiber 33 kaleidoscope 34 diffusion light transmitting plate 35 micro lens array 36 transmission optical fiber 37 core 38 clad 39a, 39b, 39c, 39d, 39e, 39f optical fiber transmission type laser device 40 Condensing lens 41 Transmission optical fibers 42a, 42b, 42c, 42d Optical fiber transmission laser devices L ₀ , L ₀₁ , L ₀₂ , L ₁ , L ₂ , L ₀₃ , L ₁₁ , L ₁₂ pulse laser light

Claims (4)

An optical fiber light guide device for guiding pulsed laser light from a pulsed laser oscillator to a transmission optical fiber, the microlens array configured by arranging condensing lenses in a compound eye shape and introducing the pulsed laser light from one end side; And a condensing optical system for condensing the pulse laser beam emitted from the other end side of the microlens array onto the transmission optical fiber. An optical fiber transmission type laser device comprising: a pulse laser oscillator; an optical fiber light guide device according to claim 1; and a transmission optical fiber for transmitting pulse laser light. A laser mirror having a rear mirror, an output mirror provided opposite to the rear mirror, an oscillator provided between the rear mirror and the output mirror, and a pulse generating means, and a condenser lens are arranged in a plane in a compound eye. A microlens array configured to introduce a pulse laser beam emitted from the laser resonator from one end side, and an optical amplifying means for amplifying and emitting the pulse laser beam emitted from the other end side of the microlens array. A pulse laser oscillator comprising: A pulse laser oscillator according to claim 3, a condensing optical system for condensing the pulse laser light emitted from the pulse laser oscillator, and a transmission optical fiber for transmitting the condensed pulse laser light. An optical fiber transmission type laser device.

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