JP7337726B2 - Pulsed laser light generation and transmission device and laser processing device - Google Patents

Description

The present invention relates to a technique for generating and transmitting ultrashort pulse laser light with a pulse width of picosecond or femtosecond class, which is used in a laser processing apparatus or the like for processing an object using laser light.

As a method for non-contact printing of best-before dates, bar codes, etc. on foods, pharmaceuticals, industrial products, etc., there is known a laser printing method that scans a laser beam with a beam scanner and irradiates the object to process the surface. there is In recent years, high-definition laser printing technology is required to print more information in a smaller area. In addition, along with the increase in printing opportunities, the diversification of printing materials is progressing. A method using an ultrashort pulse laser with a pulse width of the picosecond or femtosecond class is known as a technique capable of printing on a wide variety of materials with high definition. When a material is irradiated with a laser beam that has a short pulse width and extremely high peak power, plasma is formed on the material surface and the material is processed in a thermally non-equilibrium state, enabling extremely high-definition processing. can. Moreover, since the processing does not involve heat generation due to material absorption, it is possible to process a wide variety of materials with the same laser wavelength.

As a method for generating ultrashort pulses, a method using a solid-state laser is known. In general, solid-state lasers consist of a free-space optical system in which optical components such as an amplification medium and lenses and mirrors are arranged with high positioning accuracy. These problems are especially serious when the ultrashort pulse laser is applied to the laser printer used in the production line as described above.

On the other hand, as another ultrashort pulse generation method, a method using a fiber laser is known. For example, Patent Document 1 below discloses an ultrashort pulse fiber laser device. A fiber laser is compact because various optical components can be integrated, and is inexpensive because it is highly manufacturable. Moreover, since there is no optical axis deviation, the stability is high. In addition, it is also possible to transmit laser light with low loss through optical fiber. When applied to a laser printer used in a manufacturing line, the power source and laser body are separated from the optical scanning head so that they do not interfere with the manufacturing line. A remote location is also possible.

A problem with fiber lasers that generate ultrashort pulses is that it is difficult to increase the output power. A fiber laser has a high power density because light is confined in a very small region with a diameter of several to several tens of μm. Furthermore, the shorter the pulse width is, the higher the peak power density is because a very large pulse energy is output in an extremely short time. Therefore, there is a problem that the fiber is damaged if the power is increased too much. Therefore, it is difficult to increase the output of a fiber laser that generates ultrashort pulses, and it is difficult to apply it to a laser printer.

As a fiber with a high damage threshold, there is known a hollow-core fiber in which the core portion in which light is guided is air. Patent Document 2 discloses a method of transmitting ultrashort pulses with a high peak power density using a hollow core fiber.

JP-A-2005-174993 Japanese translation of PCT publication No. 2018-518703

The present inventors have studied an ultrashort pulse fiber laser and its output power increase for miniaturization, low cost, and high stability of an ultrashort pulse laser applied to a laser processing apparatus, particularly a laser printing apparatus. In particular, an ultrashort-pulse fiber laser using a hollow-core fiber with a high damage threshold was investigated.

As a result of the investigation, it was found that a new problem arises when trying to replace the fiber that constitutes the ultrashort pulse fiber laser with a hollow core fiber. The reason for the high damage threshold of hollow-core fibers is that the overlap between the fiber preform and guided modes in the fiber is so small that very little light traveling through the fiber is transmitted through the fiber preform. This is a favorable condition for passive devices such as those that propagate light, but it is an unsuitable condition for active devices such as optical amplifiers because a small overlap means a small effective gain and low efficiency. is. That is, it was found that it is impossible to apply the hollow core fiber to the active element constituting the ultrashort pulse fiber laser.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a compact, low-cost, highly stable, and high-output pulsed laser beam generating and transmitting apparatus for use in a laser processing apparatus or the like. do.

To give an example of the "pulsed laser light generating apparatus" of the present invention for solving the above problems, a fiber laser oscillator that outputs pulsed laser light and a pulse width of the pulsed laser light output from the fiber laser oscillator are A pulsed laser light generating and transmitting device for a laser processing device , comprising : a pulse compressor for compressing and increasing peak power; and a hollow core fiber for transmitting the pulsed laser light output from the pulse compressor.

According to the present invention, it is possible to provide a compact, low-cost, highly stable, and high-output pulsed laser beam generating and transmitting apparatus for use in a laser processing apparatus or the like.

1 is a block diagram showing the basic configuration of a pulsed laser light generating and transmitting device of the present invention; FIG. 1 is a diagram showing a configuration of a pulsed laser light generating and transmitting device according to Example 1; FIG. FIG. 4 is a diagram showing another form of the fiber laser oscillator in the pulsed laser light generation and transmission device according to the first embodiment; FIG. 10 is a diagram showing another form of the pulse compressor in the pulsed laser light generating and transmitting device according to the first embodiment; FIG. 4 is a diagram showing another form of a hollow-core fiber in the pulsed laser light generating and transmitting device according to Example 1; 1 is a block diagram showing the configuration of a laser processing apparatus according to Example 1; FIG. It is a figure which shows the application example of the laser processing apparatus which concerns on Example 1. FIG. FIG. 10 is a diagram showing the configuration of a pulsed laser light generating and transmitting device according to Example 2; FIG. 10 is a diagram showing another configuration of the pulsed laser light generating and transmitting device according to the second embodiment; FIG. 10 is a cross-sectional view of a main part in another form of the configuration of the pulsed laser light generating and transmitting device according to the second embodiment; FIG. 10 is a diagram showing the configuration of a pulsed laser light generating and transmitting device according to Example 3; FIG. 11 is a diagram showing another configuration of the pulsed laser light generating and transmitting device according to the third embodiment; FIG. 10 is a diagram showing the configuration of a pulsed laser light generating and transmitting device according to Example 4;

A pulsed laser beam generating/transmitting device and a laser processing device according to embodiments of the present invention will be described in detail below. It should be noted that the drawings shown below are only for explaining the embodiments, and the sizes of the drawings and the reduced scales described in the embodiments do not necessarily match. Also, the same components are denoted by the same reference numerals, and the description thereof will not be repeated.

FIG. 1 is a block diagram showing the basic configuration of a pulsed laser beam generating and transmitting apparatus according to an embodiment of the present invention. The pulsed laser beam generating and transmitting device comprises a fiber laser oscillator 101, a pulse compressor 102, and a transmission hollow core fiber 103 arranged in order along the direction of propagation of the laser beam. In the figure, reference numeral 104 indicates the output pulse of the fiber laser oscillator 101, reference numeral 105 indicates the output pulse of the pulse compressor 102, and reference numeral 106 indicates the transmission pulse of the hollow core fiber.

The fiber laser oscillator 101 outputs a laser pulse 104 having a wide pulse width and suppressed peak power, as indicated by reference numeral 104 . The pulse compressor 102 compresses the pulse width of the laser pulse 104 output from the fiber laser oscillator 101 and outputs a laser pulse 105 with increased peak power. The transmission hollow-core fiber 103 transmits a laser pulse 105 with a short pulse width and high peak power, and outputs a laser pulse 106 with a short pulse width and high peak power. Then, for example, in a laser printer, the light is transmitted to the vicinity of the object to be printed, and the object to be printed is irradiated with light to perform printing.

What is important here is that the laser light output from the fiber laser oscillator 101 is adjusted so that the peak power is sufficiently lower than the damage threshold of the fiber, and at the same time, the energy per pulse is required for processing. The pulse width is adjusted to be sufficiently long so as to be sufficiently larger than the energy. For example, the pulse width of the laser light output from the fiber laser oscillator 101 is 1 ns or more, the pulse width of the laser light output from the pulse compressor is 100 ps or less, and the peak power is 100 kW or more. The light whose pulse width has been compressed by the pulse compressor 102 is transmitted through the hollow core fiber 103 having a large damage threshold, so that the fiber is not damaged.

As described above, the embodiment of the present invention uses a fiber as a pulsed laser beam generation and transmission line, and thus is smaller, less costly, and more stable than conventional solid-state lasers. In addition, in conventional short-pulse fiber laser oscillators, light amplification and short-pulse laser light generation are performed in the same fiber, so it was difficult to increase the output due to the influence of fiber damage. In terms of the mode, it is possible to increase the output of the short-pulse fiber laser by performing the amplification of the light and the generation of the short-pulse laser light in independent optical systems. Furthermore, by using a hollow-core fiber with a high damage threshold, it is possible to transmit high-power short-pulse laser light.

The configurations of the fiber laser oscillator 101, the pulse compressor 102, and the hollow core fiber 103 will be described in more detail in the following examples.

FIG. 2 is a diagram showing the configuration of a pulsed laser light generating and transmitting apparatus according to Example 1 of the present invention. The fiber laser oscillator is a Q-switched fiber laser oscillator 201 and the pulse compressor is a diffraction grating pulse compressor 202 .

A Q-switched fiber laser oscillator 201 is composed of a rare-earth-doped optical fiber 204 , FBG (Fiber Bragg Grating) mirrors 205 a and 205 b , an excitation semiconductor laser 206 , and a Q switch 207 . A laser beam output from an excitation semiconductor laser 206 is guided to a rare earth-doped optical fiber 204, and in the process of being repeatedly reflected by two FBG mirrors, the light is amplified by the rare earth doped optical fiber 204, resulting in laser oscillation. Here, the Q switch 207 is made of a saturable absorber or the like, and is an optical component that generates nanosecond-class short-pulse light. The Q-switched fiber laser oscillator 201 has the advantage of being simple in configuration and relatively inexpensive. Although only one pumping semiconductor laser 206 is shown in the drawing, it is not limited to this, and a plurality of pumping semiconductor lasers 206 may be provided.

The grating pulse compressor 202 comprises a beam splitter 209, a pair of gratings 210a and 210b, and two reflecting mirrors 211 and 212. FIG. The diffraction grating is designed so that the diffraction angle differs depending on the wavelength, which causes a difference in the optical path length, so that the influence of the dispersion of the input light can be compensated for and the pulse width can be compressed. The diffraction grating pulse compressor 202 has no optical parts through which light can pass, and is entirely of a reflective type, so it has the advantage of being able to handle high-intensity light. In addition, since the amount of dispersion compensation is large, there is also the advantage that the pulse compression rate is high, or if the compression rate is the same, the device size is small.

The hollow core fiber 203 may have a hollow core portion. As a structure for confining light in holes, a metal-film hollow core fiber having a metal film and a dielectric protective film formed on the inner wall of an optical fiber having a hollow structure may be used. Alternatively, it may be a hollow core Bragg fiber in which a periodic multilayer film made of at least two dielectrics with different refractive indices is formed on the inner wall of a hollow optical fiber.

A collimator lens 208 can be used for optical connection between the Q-switched fiber laser oscillator 201 and the diffraction grating pulse compressor 202 . A condenser lens 213 can be used for optical connection between the diffraction grating pulse compressor 202 and the hollow core fiber 203 . When a lens is used, optical coupling can be performed with higher efficiency.

Although not shown in FIG. 2, an optical isolator may be inserted on the optical axis between the collimator lens 208 and the beam splitter 209 . In the embodiment in which the optical isolator is inserted, there is no return light from the pulse compressor 202 to the fiber laser oscillator 201, and a pulsed laser light generation and transmission device with higher stability can be realized.

Also, although not shown in FIG. 2, the beam splitter 209 has polarization dependence, and a 1/4 wavelength plate is inserted on the optical axis between the beam splitter 209 and the diffraction grating pair 210a. good too. In that case, the polarization directions of the light input from the fiber laser oscillator 201 to the beam splitter 209 and the light input to the beam splitter 209 after pulse compression by the diffraction grating pulse compressor 202 are orthogonal. The optical path can be changed depending on the direction of incidence of the light.

Next, another form of the fiber laser oscillator will be described with reference to FIG. The fiber laser oscillator is a MOPA (Master Oscillator Power Amplifier) type fiber laser oscillator 300 . The MOPA fiber laser oscillator 300 comprises rare earth-doped optical fibers 301a, b, pumping semiconductor lasers 302a, b, c, combiners 303a, b, a seed semiconductor laser 304, and optical isolators 305a, b, c. Laser light output from the excitation semiconductor laser 302 is combined by the combiner 303 and guided to the rare earth-doped optical fiber 301 . The light input from the seed semiconductor laser 304 to the rare-earth-doped optical fiber 301a is preamplified and then further amplified by the second rare-earth-doped optical fiber 301b. The MOPA fiber laser oscillator 300 can arbitrarily change the waveform after amplification by adjusting the repetition frequency, pulse width, pulse shape, etc. of the output light of the seed semiconductor laser 304 . Moreover, since the waveform can be actively adjusted by the seed semiconductor laser 304, there is an advantage of high stability. In FIG. 3, as in FIG. 2, the number of pumping semiconductor lasers is not limited to that shown.

Next, another form of the pulse compressor will be described with reference to FIG. The prism pulse compressor 400 comprises a beam splitter 401, a pair of prisms 402a and 402b, and two reflecting mirrors 403 and 404. FIG. Since the prism has a different angle of refraction depending on the wavelength due to material dispersion, the optical path length varies depending on the arrangement of the prism, and the influence of the dispersion of the input light can be compensated for and the pulse width can be compressed. Prisms have the advantage of being simpler in structure and less expensive than diffraction gratings. It also has the advantage of being able to compensate for both positive and negative dispersion by arranging the prisms.

Next, another form of the hollow core fiber will be described with reference to FIG. The hollow-core fiber may be a hollow-core photonic crystal fiber 500 in which holes are periodically arranged near the inner wall of the hollow-structured optical fiber. Hollow-core photonic crystal fiber 500 has hollow core portion 501 in the center of photonic crystal cladding portion 502 . It is known that an optimally designed photonic crystal forms a photonic bandgap in which light cannot propagate at a specific wavelength. Even if the core is hollow, light can be transmitted through the fiber with low loss without leaking into the clad. In addition to the low loss compared to the metal film hollow core fiber and hollow core Bragg fiber described above, it is also possible to express unique dispersion characteristics depending on the design.

FIG. 6 is a block diagram showing the configuration of the laser processing apparatus according to the first embodiment. The laser processing apparatus includes a fiber laser oscillator driver 604 for driving the fiber laser oscillator 101, a pulse compressor control driver 605 for controlling the pulse compressor 102, and part of the light output by the pulse compressor 102. A pulse width monitor 606 that measures the split pulse width, a power monitor 607 that splits a part of the light transmitted through the hollow core fiber 103 and measures the power, and a scanning laser beam that scans the light transmitted through the hollow core fiber 103. a beam scanner control driver 608 for controlling the beam scanner 603; a beam scanner position monitor 609 for inputting reflected light 611 and measuring the position of the beam scanner 603; and a laser marker controller 610 that generates signals to be input to a fiber laser oscillator driver 604 , a pulse compressor control driver 605 and a beam scanner control driver 608 . A signal input to the fiber laser oscillator driver 604 is generated based on signals output from the pulse width monitor 606 , power monitor 607 and beam scanner position monitor 609 . Also, the signal input to the pulse compressor control driver 605 is generated based on the signal output from the pulse width monitor 606 . Further, the signal input to beam scanner control driver 608 is generated based on the signal output from beam scanner position monitor 609 . In this way, the laser processing apparatus is feedback-controlled based on signals from various monitors, so that highly stable and highly accurate processing can be performed.

FIG. 7 is a diagram showing an example in which the laser processing apparatus according to the first embodiment is applied to a laser printing apparatus. A laser printer main body 701 and a scanning laser print head 702 are connected by a transmission cable 703 containing a hollow core fiber. A laser printer main body 701 that is located nearby and is larger than the scanning laser print head 702 is located at a position that does not physically interfere with the conveying device 704 . In this way, in the embodiment of the present invention, the use of the hollow core fiber makes it possible to separate the laser printer main body 701 and the scanning laser print head 702, making it possible to flexibly adapt to the type of production line. There is an advantage that it can correspond to In the laser printer of this embodiment, by irradiating the scanning laser beam 706 onto the printing objects 705a, b, and c, it is possible to print the identifier 707 on each object.

FIG. 8 is a diagram showing the configuration of a pulsed laser light generating and transmitting apparatus according to the second embodiment. In the first embodiment, the difference from the configuration of the pulsed laser light generating and transmitting apparatus described with reference to FIG. 2 is that the pulse compressor is a hollow core fiber 801 for dispersion compensation. The dispersion-compensating hollow-core fiber 801 is made of a hollow-core photonic crystal fiber or the like, and is designed so that the group velocity differs depending on the wavelength of the light transmitted through the fiber, and the influence of the dispersion of the input light is eliminated. A fiber that can be compensated to compress the pulse width. As compared with the diffraction grating pulse compressor 202 and the prism pulse compressor 400 described in the first embodiment, there is an advantage that the number of parts is smaller and the cost is smaller and the cost is lower. Furthermore, since the influence of optical axis deviation is small, there is also the advantage of high stability.

Lenses 802 and 803 are used for optical connection between the Q-switched fiber laser oscillator 201 and the dispersion-compensating hollow-core fiber 801 and for optical connection between the dispersion-compensating hollow-core fiber 801 and the transmission hollow-core fiber 203. be able to. If the lens is appropriately designed according to the NA and mode field diameter of both fibers to be optically connected, it is possible to connect them with low loss. In the drawing, the number of lenses is one, but the number of lenses is not limited to this, and a composite lens composed of a plurality of lenses may be used.

Next, another mounting form of the dispersion-compensating hollow-core fiber 801 will be described with reference to FIG. In this embodiment, the input and output ends of the dispersion-compensating hollow-core fiber 801 are directly butt-connected to the output end of the Q-switching fiber laser oscillator 201 and the input end of the transmission hollow-core fiber 203, respectively. . Compared to the above-described embodiments, the lenses 802 and 803 are not required, and the number of parts is smaller, making it smaller and cheaper. Furthermore, once it is mounted, there is no optical axis deviation, so it has the advantage of extremely high stability.

Next, a method for connecting different types of fibers will be described in detail with reference to FIG. When the solid core fiber 1001 and the hollow core fiber 1002 are optically connected, if the equivalent refractive indices of the respective propagation modes in both fibers are different, reflection occurs at the end face. In order to suppress such reflection, an antireflection film 1005 made of a dielectric multilayer film may be formed on the connecting interface. Even when the equivalent refractive indices are different, reflection is suppressed by canceling out the traveling wave and the backward wave. In the figure, reference numeral 1003 denotes a solid core portion, and reference numeral 1004 denotes a hollow core portion. In order to form the antireflection film 1005 at the interface between the two fibers, first, the antireflection film 1005 is formed on the end face of the solid core fiber 1001, and then the two fiber end faces are brought into contact with each other and spliced together. good. Furthermore, if the discharge conditions for fusion splicing are optimally designed, the mode field diameter of the optical fiber can be locally enlarged by thermal diffusion technology, and fibers of different diameters can be spliced with low loss.

FIG. 11 is a diagram showing the configuration of a pulsed laser light generating and transmitting apparatus according to the third embodiment. In Embodiment 1, the difference from the configuration of the pulsed laser light generation and transmission device described with reference to FIG. The point is that a highly nonlinear fiber 1101 for spectral width expansion, which is a width expander, is inserted. The highly nonlinear fiber for spectral width expansion 1101 is made of a solid-core photonic crystal fiber or the like, and the refractive index of the fiber strongly depends on the intensity of the transmitted light. A fiber that can be expanded in width. When the chirping (wavelength fluctuation) of the output light of the laser oscillator can be ignored, the spectral width and the pulse width have a Fourier transform relational expression, so widening the spectral width can make the pulse width narrower. . That is, this embodiment has the advantage of being able to generate laser light with higher waveform quality. The nonlinear constant of the spectral width expander is preferably 50 W ⁻¹ km ⁻¹ or more.

Optical connection between the Q-switched fiber laser oscillator 201 and the highly nonlinear fiber for spectral width expansion 1101 may be achieved by fiber fusion splicing as shown in the figure, or by using a lens (not shown). may Also, a collimator lens 1102 can be used for optical connection between the highly nonlinear fiber 1101 for spectral width expansion and the diffraction grating pulse compressor 202 .

Next, another form using the highly nonlinear fiber 1101 for expanding the spectral width will be described with reference to FIG. This embodiment is different in that the diffraction grating pulse compressor 202 in the above-described embodiment is replaced with a dispersion compensating hollow core fiber 801, and all of the fibers are spliced together by fusion splicing. It is smaller and cheaper due to fewer parts compared to the above-described embodiments. Furthermore, once it is mounted, there is no optical axis deviation, so it has the advantage of extremely high stability.

FIG. 13 is a diagram showing the configuration of a pulsed laser light generating and transmitting apparatus according to the fourth embodiment. In Embodiment 1, the difference from the configuration of the pulsed laser beam generating and transmitting device described with reference to FIG. is placed. The nonlinear optical crystal 1301 is a crystal that responds nonlinearly to incident light due to polarization within the crystal and that has birefringence. For example, KTiOPO ₄ (KTP), CsLiB ₆ O ₁₀ (CLBO), LiB ₃ O ₅ (LBO), KH ₂ PO ₄ (KDP), LiNbO ₃ (LN) and the like may be used. Also, MgO:LiNbO ₃ (MgLN) in which MgO is mixed with LN crystal, PPLN or PPMgLN in which LN crystal or MgLN crystal has a periodically inverted structure, or the like may be used. Short wavelength laser light is generated when the wavelength, phase, polarization, etc. of the light incident on these crystals satisfies certain matching conditions. For example, light with a wavelength of 1064 nm is incident on the LBO crystal to generate light with a wavelength of 532 nm (second harmonic generation), and light with wavelengths of 1064 nm and 532 nm is incident on the LBO crystal to perform sum frequency generation. It is also possible to generate light with a wavelength of 355 nm (third harmonic generation). As another example, light with a wavelength of 1064 nm is incident on a KTP crystal to generate light with a wavelength of 532 nm (second harmonic generation), and light with a wavelength of 532 nm is incident on a CLBO crystal to generate light with a wavelength of 266 nm. Light can be generated (fourth harmonic generation).

By converting the wavelength using the nonlinear optical crystal 1301, the object can be irradiated with light having a wavelength that is less reflected from the object and highly absorbed. This enables efficient processing with small energy. Depending on the material of the object to be processed, the generation of unnecessary heat can be suppressed, and the object can be processed more finely and with high quality. In addition, since the beam diameter when condensed by the same lens system is proportional to the wavelength, shortening the wavelength of the laser light can reduce the beam diameter, enabling finer and higher-quality processing. .

<Regarding Modifications of the Present Invention>
The present invention is not limited to the embodiments described above, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. In addition, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

101: Fiber laser oscillator 102: Pulse compressor 103: Hollow core fiber for transmission 104: Output pulse from fiber laser oscillator 105: Output pulse from pulse compressor 106: Output pulse from hollow core fiber 201: Q-switched fiber laser oscillator 202 : grating pulse compressor
203: Hollow core fiber for transmission
204: Rare earth-doped optical fiber 205a, b: FBG (Fiber Bragg Grating) mirror 206: Excitation semiconductor laser 207: Q switch 208: Collimating lens 209: Beam splitter 210a, b: Diffraction grating pair 211, 212: Reflecting mirror 213: Condensing lens 300: MOPA fiber laser oscillator 301a, b: Rare earth-doped optical fiber 302a, b, c: Pumping semiconductor laser 303a, b: Combiner 304: Seed semiconductor laser 305a, b, c: Optical isolator 400: Prism pulse compressor
401: beam splitter 402a, b: prism pair 403, 404: reflecting mirror 500: hollow core photonic crystal fiber 501: hollow core section 502: photonic crystal clad section 601: user input signal 602: scanning laser light 603: beam scanner 604: Fiber laser oscillator driver 605: Pulse compressor control driver 606: Pulse width monitor 607: Power monitor 608: Beam scanner control driver 609: Beam scanner position monitor 610: Laser marker controller 611: Reflected light 701: Laser printer main body 702: Scanning laser print head 703: Transmission cable 704: Conveying devices 705a, b, c: Printed object 706: Scanning laser light 707: Identifier 801: Hollow core fibers for dispersion compensation 802, 803: Lens 1001: Solid core fiber 1002 : Hollow core fiber 1003: Solid core part 1004: Hollow core part 1005: Anti-reflection film 1101: Highly nonlinear fiber for expanding spectrum width 1102: Collimating lens 1301: Nonlinear optical crystal

Claims (15)

a fiber laser oscillator that outputs pulsed laser light;
a pulse compressor for compressing the pulse width of the pulsed laser light output from the fiber laser oscillator and increasing the peak power ;
a hollow core fiber that transmits the pulsed laser light output from the pulse compressor;
A pulsed laser light generation and transmission device for a laser processing device comprising: The pulsed laser light output from the fiber laser oscillator has a pulse width adjusted so that the peak power is lower than the damage threshold of the fiber and the energy per pulse is higher than the energy required for processing. there is
2. The pulsed laser light generating and transmitting device according to claim 1. The pulse width of the pulsed laser light output from the fiber laser oscillator is 1 ns or more,
3. The pulsed laser light generating and transmitting device according to claim 2 , wherein the pulsed laser light output from said pulse compressor has a pulse width of 100 ps or less and a peak power of 100 kW or more. The fiber laser oscillator is
a semiconductor laser for excitation;
a rare-earth-doped optical fiber for optical amplification;
a Q switch for generating pulsed laser light;
a fiber Bragg grating for light reflection;
2. The pulsed laser light generating and transmitting device according to claim 1, which is a Q-switched fiber laser oscillator comprising: The fiber laser oscillator is
a first semiconductor laser for generating pulsed light;
a second semiconductor laser for excitation;
a rare-earth-doped optical fiber for optical amplification;
an optical isolator for optical rectification;
2. The pulsed laser light generation and transmission device according to claim 1, which is a MOPA type fiber laser oscillator comprising: The pulse compressor is
2. The pulsed laser light generating and transmitting apparatus according to claim 1, which is a diffraction grating pulse compressor having a diffraction grating pair for dispersion compensation. The pulse compressor is
2. The pulsed laser light generating and transmitting device according to claim 1, which is a prism pulse compressor having a prism pair for dispersion compensation. The hollow core fiber is
A metal film hollow core fiber in which a metal film is formed on the inner wall of an optical fiber having a hollow structure and a dielectric protective film is formed on the metal film, or
2. A device for generating and transmitting pulsed laser light according to claim 1, which is a hollow-core Bragg fiber in which a periodic multilayer film composed of at least two dielectrics having different refractive indices is formed on the inner wall of the hollow-structured optical fiber. The hollow core fiber is
2. The apparatus for generating and transmitting pulsed laser light according to claim 1, which is a hollow-core photonic crystal fiber in which holes are periodically arranged in the vicinity of the inner wall of the optical fiber having a hollow structure. The pulse compressor is
2. The pulsed laser light generation and transmission device according to claim 1, which is a hollow core fiber for dispersion compensation. The fiber laser oscillator is
A laser oscillator that outputs a pulsed laser beam from the end face of a solid core fiber,
An antireflection film is formed on an end surface of the solid core fiber,
11. The pulse laser according to claim 10, wherein the end face of the solid core fiber on which the antireflection coating is formed and one end face of the hollow core fiber for dispersion compensation are spliced together with their optical axes aligned. Light generation and transmission equipment. on the optical axis between the fiber laser oscillator and the pulse compressor,
2. The pulsed laser light generating and transmitting apparatus according to claim 1, further comprising a spectral width expander for expanding the spectral width. on the optical axis between the pulse compressor and the hollow core fiber for optical transmission,
2. A pulsed laser light generating and transmitting device according to claim 1, wherein a nonlinear optical crystal for converting the wavelength of light is arranged. a fiber laser oscillator that outputs pulsed laser light;
a pulse compressor for compressing the pulse width of the pulsed laser light output from the fiber laser oscillator;
a hollow core fiber that transmits the pulsed laser light output from the pulse compressor;
a fiber laser oscillator driver for driving the fiber laser oscillator;
a pulse compressor control driver for controlling the pulse compressor;
a pulse width monitor for branching a portion of the light output from the pulse compressor and measuring the pulse width;
a power monitor for branching a part of the light transmitted through the hollow core fiber and measuring the power;
a beam scanner that scans the light transmitted through the hollow core fiber;
a beam scanner control driver for controlling the beam scanner;
a beam scanner position monitor for measuring the position of the beam scanner;
a laser marker controller that generates signals that are input to the fiber laser oscillator driver, the pulse compressor control driver, and the beam scanner control driver;
with
A signal input to the fiber laser oscillator driver is generated based on signals output from the pulse width monitor, the power monitor, and the beam scanner position monitor,
A signal input to the pulse compressor control driver is generated based on a signal output from the pulse width monitor,
A laser processing apparatus in which a signal input to the beam scanner control driver is generated based on a signal output from the beam scanner position monitor. Laser processing equipment
15. The laser processing apparatus according to claim 14, wherein the laser processing apparatus is a laser printing apparatus that prints on an object to be printed using the pulsed laser beam.

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