JP2001068769A - Laser device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] An optical fiber can be prevented from being damaged by external laser light irradiation. A laser device for isotope separation includes a plurality of solid-state laser devices 1 and a plurality of optical fibers 3 for transmitting excitation laser light 2 emitted from each of the solid-state laser devices 1.
A plurality of amplifiers 6, 7, 7, which are irradiated with one oscillator 5 and the excitation laser light 2 emitted from each optical fiber 3.
And a duct 40 in which the optical fiber 3 is provided between the solid-state laser device 1 and the dye laser device 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser device having a high output and a variable oscillation wavelength used for, for example, laser isotope separation.

[0002]

2. Description of the Related Art A laser device used for laser isotope separation is provided with a dye laser device whose oscillation wavelength can be varied because it is necessary to precisely tune a wavelength specific to a target isotope. This dye laser device is required to have high beam quality such as a narrow spectrum width and small wavefront distortion, and at the same time, a high laser output of several kW. For this reason, a dye laser device used for laser isotope separation has a MOPA (Master) in which an oscillator for generating a high-quality beam and a plurality of amplifiers for sequentially amplifying the beam to a high power are connected in series. Oscilator Power Am
plifiers).

In a dye laser device which is a multistage amplifier, the laser light oscillates and is amplified by being irradiated with the excitation laser light generated by the excitation laser device. As this excitation laser device, a copper vapor laser device (MOP)
A) and a solid-state laser device are employed.

FIG. 6 is a schematic view of a conventional laser apparatus for isotope separation described in, for example, JP-A-5-218540. In FIG. 6, reference numeral 1 denotes, for example, YAG doped with neodymium as a laser medium (structural formula: Y ₃ Al ₅ O
₁₂ ) A solid-state laser device using a crystal, 3 is an optical fiber for transmitting an excitation laser beam from the solid-state laser device 1 which is an excitation laser device, 5 is an oscillator of the dye laser device 4, and 6 is a dye inside which is a laser medium. A first first amplifier in which a solution is stored, 7 is a second second amplifier, and 8 is a third third amplifier. The oscillator 5, the first amplifier 6, the second amplifier 7, and the third amplifier 8 constitute a dye laser device 4 which is a multistage amplifier, and the dye laser device 4 emits a dye laser beam 9.

Next, the operation of the laser apparatus for isotope separation having the above configuration will be described. In the solid-state laser device 1, when excited by a semiconductor laser beam, a laser beam called a fundamental wave having an oscillation wavelength of 1064 nm is generated. This fundamental wave
Using an optical crystal for wavelength conversion such as TP (structural formula: KTiOPO ₄ ), the optical frequency is doubled, that is, the oscillation wavelength is reduced to 532
nm and emit as excitation laser light. The output of the excitation laser light in the solid-state laser device 1 is 30W to 50W.
W.

Next, the pump laser light emitted from the plurality of solid-state laser devices 1 is supplied to the oscillator 5, the first amplifier 6, the second amplifier 7, and the third amplifier 8 via the optical fiber 3.
And irradiates the dye solution as a laser medium in each of the amplifiers 6, 7, 8 to excite the dye. Since more pumping power is required at a later stage, the number of optical fibers 3 to be connected increases in the order of the oscillator 5 <the first amplifier 6 <the second amplifier 7 <the third amplifier 8. The core diameter of a commonly used optical fiber for transmitting high-power laser light is 0.44 to 1.2 mm.

Although the oscillator 5 constituting the dye laser device 4 has a low output (1 W or less), a wavelength selecting element such as an etalon provided in the oscillator 5 is provided in the oscillator 5 so that the oscillation wavelength of the dye laser light can be varied. The oscillation wavelength is controlled with high precision. The dye laser light from the oscillator 5 is supplied to a plurality of amplifiers 6,
Since the light is amplified with high efficiency in steps 7 and 8, high-quality laser light is generated. The dye laser light emitted from the oscillator 5 is
The light is sequentially amplified through a first amplifier 6, a second amplifier 7, and a third amplifier 8, and finally emitted as a high-power dye laser light 9 on the order of kW. At this time, the beam quality such as wavelength accuracy is maintained as it is by the optical amplification, so that the dye laser beam 9 having high output and high quality can be obtained.

[0008]

As described above, a conventional laser device for isotope separation is composed of a large number of solid-state laser devices.
, One optical fiber 3 is always connected to one solid-state laser device 1, and this optical fiber 3 is composed of an oscillator 5, a first amplifier 6, and a second It is necessary to lay the amplifier 7 and the third amplifier 8 respectively. Since the optical fiber 3 is exposed to the outside, there is a problem that a laser beam is irradiated from the outside for some reason, and the optical fiber 3 is damaged by the laser beam.

Further, since the optical fiber 3 transmits laser light using the total reflection angle of quartz glass, if the optical fiber 3 bends beyond an allowable angle, the optical fiber 3 deviates from the total reflection angle and a part of the laser light leaks from the optical fiber 3. As a result, the transmission efficiency of the optical fiber 3 is reduced, and the optical fiber 3 is bent at an acute angle at the time of laying or exchanging work, so that the optical fiber 3 is damaged.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is possible to prevent the optical fiber from being damaged by external laser light irradiation, and to lay and replace the optical fiber. It is an object of the present invention to obtain a laser device that can prevent breakage that occurs sometimes and that has improved optical fiber transmission efficiency.

[0011]

According to a first aspect of the present invention, there is provided a laser apparatus comprising: a plurality of excitation laser apparatuses; and a plurality of optical fibers for transmitting excitation laser light emitted from each of the excitation laser apparatuses. A multistage amplifier having a plurality of amplifiers to which the excitation laser light emitted from each of the optical fibers is irradiated, and a duct provided with the optical fiber disposed inside between the excitation laser device and the multistage amplifier It is provided with.

According to a second aspect of the present invention, in the duct, the duct is provided with a support provided at at least one of the entrance of the excitation laser beam and the exit of the excitation laser beam to hold the optical fiber.

In the laser device according to a third aspect of the present invention, the duct is provided with a partition plate for partitioning each bundle fiber in which a plurality of optical fibers are bundled.

According to a fourth aspect of the present invention, there is provided a laser device having a support fixed to the excitation laser device and holding an optical fiber connected to the excitation laser device.

According to a fifth aspect of the present invention, in the laser device, the supporting member includes a curved tube provided with an optical fiber therein, and a clamp provided at one end of the curved tube for holding the optical fiber. It is.

In the laser device according to claim 6 of the present invention, the curved tube has a radius of curvature of 250 mm or more.

In the laser device according to claim 7 of the present invention, the clamp has an elastic body for elastically holding the optical fiber.

In the laser device according to claim 8 of the present invention, the multistage amplifier is a dye laser device.

In the laser device according to the ninth aspect of the present invention, the excitation laser device is a solid-state laser device using a YAG crystal.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a laser apparatus for isotope separation according to Embodiment 1 of the present invention will be described. FIG. 1 is a schematic diagram of a laser apparatus for isotope separation according to Embodiment 1 of the present invention. In the figure, 1 is a solid-state laser device using, for example, a neodymium-doped YAG (structural formula: Y ₃ Al ₅ O ₁₂ ) crystal as a laser medium, and 3 is a pump laser from the solid-state laser device 1 which is a pump laser device. This is an optical fiber made of quartz glass for transmitting light 2. Reference numeral 5 denotes an oscillator, 6 denotes a first first amplifier in which a dye solution as a laser medium is stored, 7 denotes a second second amplifier, and 8 denotes a third third amplifier. ,
The oscillator 5, the first amplifier 6, the second amplifier 7, and the third amplifier 8 constitute the dye laser device 4, and the dye laser device 4 emits dye laser light 9.

Reference numeral 10 denotes a bundle fiber obtained by bonding and bundling a plurality of optical fibers 3 with an adhesive, 11 denotes an output port of the bundle fiber 10, 12 denotes a laser beam emitted from the output port 11 of the bundle fiber 10, and 13 denotes a laser beam. 1
2 is a transfer optical system for irradiating 2 to the first amplifier 6. The above mechanisms are provided symmetrically in the vertical direction. Note that the mechanism for irradiating the second amplifier 7 and the third amplifier 8 with laser light is the same as that of the first amplifier 6, and a description thereof will be omitted.

Reference numeral 14 denotes a gantry on which the solid-state laser devices 1 are mounted on the floor surface 50, for example, and the solid-state laser devices 1 are stacked in ten stages, and a plurality of solid-state laser devices 1 are arranged per stage. 20A is a first support which is provided at a connection portion of the optical fiber 3 connected to the solid-state laser device 1 and holds the optical fiber 3.
0B is a second support fixed to one end of the duct 40 and holding the optical fiber 3, and 20C is fixed to an intermediate part of the duct 40 and holds a third bind fiber 10.
It is a support tool.

FIG. 2 is a diagram showing an area A surrounded by a dotted line in FIG. In the drawing, reference numeral 15 denotes a door for attaching and detaching an optical fiber provided on a base 14, reference numeral 16 denotes a coupler for allowing the excitation laser light 2 to enter the optical fiber 3, and reference numeral 21a denotes a mounting with a ring-shaped screw hole fixed to the base 14. The fitting 22a is connected to the mounting fitting 21a and has a radius of curvature of 2 from the center point 0.
It is a curved tube of 50 mm or more and faces the direction of the path on which the optical fiber 3 is arranged. A clamp 30a is connected to the curved tube 22a and fixes the optical fiber 3 passing through the curved tube 22a. The first support 20A is constituted by the mounting metal 21a, the curved tube 22a, and the clamp 30a.

The clamp 30a includes an outer frame 31a and an outer frame 3
Elastic body 32a such as urethane rubber fitted in 1a
And a hinge 33a for rotatably supporting the outer frame 31a, and a bolt 34a and a nut 35a for fixing the outer frame 31a in a closed state. FIG. 3 is a sectional view when the optical fiber 3 is fixed by the clamp 30a. Elastic body 32
A gap 36 is formed when the optical fiber 3 is sandwiched by a, and the width of the gap 36 is set to be smaller than the diameter of the optical fiber 3.

FIG. 4 is a diagram showing a region B surrounded by a dotted line in FIG. In the figure, 41 is a duct cover, 42 is a lower frame having a U-shaped cross section, and 43 is a partition plate for arranging the bundle fibers 10 separately. The bundle fiber 10 configured by bundling the plurality of optical fibers 3 is partitioned by the partition plate 43 up to the vicinity of the second support 20B, but thereafter separated into individual optical fibers 3. The duct 40 includes the duct cover 41, the lower frame 42, and the partition plate 43.

Reference numeral 21b denotes a mounting bracket with a ring-shaped screw hole fixed to the duct 40 (the wall surface of the duct to be fixed is omitted in FIG. 4), and reference numeral 22b denotes the mounting bracket 21.
b is a curved tube having a radius of curvature of 250 mm or more, which faces the direction in which the optical fiber 3 is arranged. A clamp 30b is connected to the curved tube 22b and fixes a plurality of optical fibers 3 passing through the curved tube 22b. In addition, the second support 20B is configured by the fitting 21b, the curved tube 22b, and the clamp 30b. The structure of the clamp 30b is the same as that of the clamp 30a of the first support 20A.
Is the same as

FIG. 5 is a diagram showing a region C surrounded by a dotted line in FIG. 21c is a mounting fitting with a ring-shaped screw hole fixed to the opening 44 of the duct 40, 22c is a curved pipe having a radius of curvature of 250 mm or more connected to the mounting fitting 21c,
A clamp 30c is connected to the curved tube 22c and fixes the bundle fiber 10 passing through the curved tube 22c. In addition,
A third support 20C is configured by the fitting 21c, the curved tube 22c, and the clamp 30c. Clamp 30c
Are an outer frame 31c, an elastic body 32c such as urethane rubber fitted in the outer frame 31c, a hinge 33c rotatably supporting the outer frame 31c, a bolt 34c for fixing the outer frame 31c in a closed state, and A nut 35c is provided. In addition,
The mechanism for irradiating the second amplifier 7 and the third amplifier 8 with the laser beam 12 is also the same as that of the first amplifier 6, and the description is omitted.

In the laser apparatus for isotope separation having the above structure, when the kW-class dye laser light 9 is generated, the output ratio of the excitation laser light in each of the amplifiers 6, 7, and 8 constituting the dye laser apparatus 4 is as follows. In general, when the output of the first amplifier 6 is 1, the second amplifier 7 is 2 and the third amplifier 8 is 4. Here, for example, the output of the dye laser light is 2 k
In the case of W, the conversion efficiency of the dye laser device 4 (output of the dye laser light 9 / output of the excitation laser light 2) is about 40%, so that the output of the excitation laser light needs to be 5 kW.

When the laser light 12 is irradiated from both sides of the amplifiers 6, 7, 8 as shown in FIG. 1, the output of the laser light 12 irradiated from one side is 2.5 kW. Since the solid-state laser device 1 is used as an excitation laser device and the output of one solid-state laser device 1 is about 50 W, the number of the solid-state laser devices 1 is 50 (= 2.5 kW / 0.05 kW). Therefore, the number of solid-state laser devices 1 in each of the amplifiers 6, 7, and 8 is about seven (= 50/7) in the first amplifier 6, and
The number of amplifiers 7 is about 14 (= 50 × 2/7), and that of the third amplifier 8 is about 28 (= 50 × 4/7).

In this embodiment, one optical fiber 3 is connected to one solid-state laser device 1, and a bundle fiber 10 in which seven optical fibers 3 are bundled is provided on one side of the first amplifier 6. I need a book. The second amplifier 7 requires two bundled fibers 10 on which one optical fiber 3 is bundled on one side, and the third amplifier 8 requires four bundled fibers 10 on which seven optical fibers 3 are bundled. .

A duct 40 provided between the solid-state laser device 1 and the dye laser device 4 extends the optical fiber 3 to the amplifiers 6, 7, and 8 of the dye laser device 4. In FIG. 1, a plurality of optical fibers 3 from the lower five solid-state laser devices 1 are provided on a lower side of a duct 40 provided with a plurality of optical fibers 3 from the upper five-stage solid-state laser devices 1. It is arranged in the duct 40.

Since the output of the dye laser light generated by the oscillator 5 is smaller (less than 1 W) than the output of the solid-state laser device 1 (about 50 W), the solid-state laser device 1 dedicated to low output (about 5 W) is used. Occur. At this time, the oscillation wavelength is controlled with high accuracy by a wavelength selection element such as an etalon provided in the oscillator 5 so that the oscillation wavelength of the dye laser light can be varied. Further, since the dye laser light of the oscillator 5 is highly efficiently amplified by the plurality of amplifiers 6, 7, and 8, high-quality dye laser light 9 is generated.

Next, the work of laying the optical fiber 3 will be described according to the procedure. The bundle fiber 10 has a diameter of 1
It is wound concentrically about m. When laying this single bundle fiber 10 above the first amplifier 6,
Remove the duct cover 41 and remove the bundle fiber 10
Opening 4 in which exit port 11 is provided in lower frame 42 of duct 40
4, a predetermined length is pulled out from one end of the curved tube 22c of the third support 20C. Then, after setting the bundle fiber 10 at the center of the clamp 30c, the outer frame 31c is closed, and the outer frame 31 is fixed by bolts 34c and nuts 35c.
Tighten. Since the bundle fiber 10 is elastically supported by the elastic body 32c, the bundle fiber 10 is not displaced by its own weight. On the other hand, the bundle fiber 10 wound concentrically is arranged on the lower frame 42 of the duct 40 while unwinding, and laid toward the solid-state laser device 1. At the time of this laying, the partition fibers 43 do not cause the bundle fibers 10 to intersect.

The bundle fiber 10 is divided into partition plates 43
After laying up to the vicinity of the end, the bundle fiber 10 is divided into seven optical fibers 3 as shown in FIG. 4 (in the figure, the total number of optical fibers 3 is not shown). When the partition plate 43 is provided up to the end of the duct 40, the bundle fiber 10 is
When the bundle fiber 10 hits the end face of the partition plate 43 when it is laid up, down, left and right, the optical fiber 3 may be broken, so the partition plate 43 is several hundred mm to 1000 mm deeper than the end of the duct 40. It is provided to penetrate.

Thereafter, the tips of the three optical fibers 3 are passed through the curved pipes 22b of the respective second supports 20B, and then the seven optical fibers 3 are fixed to the second supports 20B using the clamps 30b. I do. At this time, since each optical fiber 3 is elastically supported at an interval by an elastic body of the clamp 30b, the optical fibers 3 can be laid without intersecting in the curved tube 22b. Finally, the seven optical fibers 3 in the curved tube 22b of the second support 20B are connected to the seven solid-state laser devices 1 arranged on the mount 14, respectively. To this end, predetermined optical fibers 3 are passed one by one through the curved tubes 22a of each first support 20A, and the optical fibers 3 are fixed by clamps 30a. After that, the mounting bracket 21a is fixed to the gantry 14 with screws, and the first support 20A is mounted. Next, the door 15 is opened, and the optical fiber 3 is connected to the coupler 1.
6 and, after completing the connection, the door 15 is closed. In addition,
To remove the optical fiber 3 at the time of replacement, the procedure is reversed.

Hereinafter, similarly, the work of laying the optical fiber 3 on the second amplifier 7 and the third amplifier 8 is performed in the same procedure.

In the above embodiment, the dedicated solid-state laser device 1 is used as the excitation laser device used for the oscillator 5, but the excitation laser light 2 emitted from the solid-state laser device 1 arranged on the gantry 14 is used. May be used. As a dye laser device which is a multi-stage amplifier, three amplifiers 6,
Although the apparatus includes the oscillators 7 and 8 and the oscillator, the number of amplifiers can be increased or decreased according to the required laser output of the dye laser light. Although the isotope separation laser device has been described as a laser device, the present invention may be, for example, a laser processing device or a laser medical device, in which a plurality of excitation laser devices are operated in parallel to generate excitation laser light. The present invention can be applied to any laser device that transmits by an optical fiber. Further, the support may be provided at only one of the entrance of the excitation laser light and the exit of the excitation laser light in the duct 40.

[0038]

As described above, according to the laser device of the first aspect of the present invention, a plurality of excitation laser devices and a plurality of excitation laser beams transmitted from the respective excitation laser devices are transmitted. One optical fiber and one oscillator,
And a multi-stage amplifier having a plurality of amplifiers to which the excitation laser light emitted from each of the optical fibers is irradiated, and the optical fiber disposed and provided between the excitation laser device and the multi-stage amplifier. The provision of the duct makes it possible to prevent the optical fiber from being damaged by external laser light irradiation. The optical fiber is held by a duct.

Further, in the laser device according to the second aspect of the present invention, since the duct has the support member provided at at least one of the entrance of the excitation laser beam and the exit of the excitation laser beam and holding the optical fiber, When laying and exchanging optical fibers, crossover of a plurality of optical fibers can be prevented, workability can be improved, and breakage can be prevented.

Further, in the laser device according to the third aspect of the present invention, since the duct is provided with partition plates for partitioning each bundle fiber in which a plurality of optical fibers are bundled, the laying and replacement of the optical fibers are performed. At times, it is possible to prevent the bundle fibers from intermingling.

Further, in the laser device according to the fourth aspect of the present invention, since the support device holding the optical fiber fixed to the excitation laser device and connected to the excitation laser device is provided, the optical fiber for the excitation laser device is provided. At the time of installation or replacement, damage to the optical fiber can be prevented.

Further, in the laser device according to the fifth aspect of the present invention, the support member includes a curved tube having an optical fiber provided therein, and a clamp provided at one end of the curved tube for holding the optical fiber. Therefore, a decrease in the transmission efficiency of the optical fiber is suppressed, and the output is improved.

Further, in the laser device according to claim 6 of the present invention, since the radius of curvature of the curved tube is 250 mm or more, the optical fiber is not bent below the recommended radius of curvature, and the transmission efficiency of the optical fiber is reduced. Is suppressed, and the output is improved.

Further, in the laser device according to claim 7 of the present invention, since the clamp has the elastic body for elastically holding the optical fiber, the optical fiber is held without being damaged.

Further, in the laser device according to claim 8 of the present invention, since the multistage amplifier is a dye laser device, it is possible to generate high-quality, high-output laser light.

In the laser device according to the ninth aspect of the present invention, since the excitation laser device is a solid-state laser device using a YAG crystal, it is possible to generate high-quality, high-output excitation laser light. it can.

[Brief description of the drawings]

FIG. 1 is a layout diagram of a laser device for isotope separation according to Embodiment 1 of the present invention.

FIG. 2 is a perspective view of a region A surrounded by a dotted line in FIG.

FIG. 3 is a sectional view of the first support of FIG. 1;

FIG. 4 is a perspective view of a region B surrounded by a dotted line in FIG.

5 is a perspective view of a region C surrounded by a dotted line in FIG.

FIG. 6 is a configuration diagram of a conventional laser apparatus for isotope separation.

[Explanation of symbols]

2 Excitation laser light, 3 optical fiber, 5 oscillator, 6
First amplifier, 7 second amplifier, 8 third amplifier,
9 dye laser beam, 10 bundle fiber, 11
Outlet of bundle fiber, 12 laser beam 13 transfer optical system, 20A first support, 20B second support, 20C third support, 22a, 22b, 22c,
Curved pipe 30a, 30b, 30c Clamp, 32a, 3
2c elastic body, 40 duct, 43 partition plate.

Claims (9)

[Claims] 1. A plurality of excitation laser devices, a plurality of optical fibers for transmitting excitation laser light emitted from each of the excitation laser devices, and a plurality of irradiation with the excitation laser light emitted from each of the optical fibers. A laser device comprising: a multi-stage amplifier having a plurality of amplifiers; and a duct in which the optical fiber is provided between the pump laser device and the multi-stage amplifier. 2. The laser device according to claim 1, further comprising: a support provided at at least one of an entrance of the excitation laser beam and an exit of the excitation laser beam in the duct to hold an optical fiber. 3. The laser device according to claim 1, wherein the duct is provided with a partition plate for partitioning each bundle fiber in which a plurality of optical fibers are bundled. 4. The laser device according to claim 1, further comprising a support fixed to the excitation laser device and holding an optical fiber connected to the excitation laser device. 5. The supporting tool according to claim 2, further comprising: a bent tube having an optical fiber provided therein; and a clamp provided at one end of the bent tube and holding the optical fiber. A laser device according to claim 1. 6. The laser device according to claim 5, wherein the curved tube has a radius of curvature of 250 mm or more. 7. The laser device according to claim 5, wherein the clamp has an elastic body for elastically holding the optical fiber. 8. The laser device according to claim 1, wherein the multistage amplifier is a dye laser device. 9. The laser device according to claim 1, wherein the excitation laser device is a solid-state laser device using a YAG crystal.