JP2001177171A - Solid state laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable and high-power solid state laser device which generates a high quality laser beam. SOLUTION: The solid state laser device for oscillating laser beams by stimulating a laser medium 1 with laser beams 8 from a plurality of semiconductor lasers 10, 11, 12, 13 disposed in a section perpendicular to the axis of the solid stage laser medium 1, comprises LD driving system 60, 61, 62, 63 respectively for the semiconductor lasers 10, 11, 12, 13 so that the outputs of the semiconductor lasers 10, 11, 12, 13 are approximately equal to approximately uniformly stimulate the solid state laser medium 1 in the section perpendicular to the axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser (Laser Diode:
The present invention relates to a solid-state laser device which is optically pumped by the laser light from the above (1) and stably generates a high-quality laser beam at a high output.

[0002]

2. Description of the Related Art FIG.
FIG. 4 is a cross-sectional configuration diagram showing a conventional LD-pumped solid-state laser device disclosed in Japanese Patent Application Publication No. 4 (JP-A) No. 4 (Kokai) No. 4 and is a cross-section taken along a plane perpendicular to the optical axis, that is, a cross-sectional view. In FIG. 13, 21 is a solid-state laser medium, 22 is a cooling sleeve, 23 is a heat sink, 24
Is a waveguide, 25 is a holding member, 26 is a mounting hole, 27 is a holder, 28 is an LD as an excitation light source, and 29 is a cooling passage.

The solid-state laser medium 21 includes a cooling sleeve 2
2, a cooling medium for cooling the solid-state laser medium 21 flows through the cooling sleeve 22. Around the cooling sleeve 22, eight prismatic heat sinks 23 having a trapezoidal cross section and having a flat inner surface 23 a and an outer surface 23 b are arranged annularly with their side surfaces adjacent to each other. LD28 is a heat sink 2
The light guide path 24 formed in the inside 3 is provided at an end on the outer surface side. The heat sink 23 is provided with a cooling passage 29 through which a cooling medium flows. By flowing the cooling medium, the semiconductor laser 28 held by the holding member 25 via the holder 27 is cooled.

When a current is applied to the LD 28 to drive it, L
The D light passes through the light guide path 24 and optically excites the solid-state laser medium 21 to generate a laser beam. At this time, by controlling the temperature of the LD 28 to a predetermined temperature by the cooling medium, the LD 2
The wavelength of the LD light output from the solid-state laser medium 2
1 can be set near the peak of the absorption spectrum, and as a result, efficient laser oscillation can be performed.

[0005]

The conventional L as described above is used.
In the D-pumped solid-state laser device, since the temperature control of a plurality of LDs used in one device is not individually performed, it is not possible to correct the wavelength variation in each LD,
The excitation intensity in the section perpendicular to the optical axis of the solid-state laser medium was not uniform. If the excitation intensity is non-uniform, the center of the excited region of the solid-state laser medium does not coincide with the optical axis of the generated laser beam, which causes a problem that sufficient output cannot be obtained. Also, because the shape of the laser beam is distorted,
When a laser beam is used for processing, there is also a problem that processing performance deteriorates. In addition, when laser oscillation is performed by connecting a plurality of LD pumping modules in series, it is difficult to adjust the laser oscillation, and a sufficient output is obtained because the optical axis of the laser beam and the axis of the solid-state laser medium are shifted. Therefore, there is a problem that stable oscillation cannot be performed. In addition, all L
Since the wavelength of D cannot be corrected near the peak of the absorption spectrum of the solid-state laser medium, there has been a problem that sufficient excitation efficiency cannot be obtained.

In addition, the conventional solid-state laser device does not have a mechanism for individually controlling the outputs of a plurality of LDs used in one device, so that it is not possible to correct variations in the output of each LD. Therefore, similarly to the above, there is a problem that the excitation intensity of the solid-state laser medium becomes nonuniform, a sufficient output cannot be obtained, and a stable laser beam cannot be generated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and uniformly excites a solid-state laser medium to generate a high-quality laser beam and stably obtain a high output. It is intended to obtain a solid-state laser device that can be used.

[0008]

According to a first aspect of the present invention, there is provided a solid-state laser device having a plurality of semiconductor lasers arranged in a section perpendicular to an axis of a solid-state laser medium, and the solid-state laser being driven by the light of the semiconductor laser. In exciting the medium,
The output characteristic or wavelength characteristic of each of the semiconductor lasers is controlled so that the solid-state laser medium is excited almost uniformly in a section perpendicular to the axis.

Further, a solid-state laser device according to a second configuration of the present invention is arranged such that a plurality of semiconductor lasers are arranged along an axial direction of the solid-state laser medium, and the solid-state laser medium is excited by light of the semiconductor laser. The output characteristic or the wavelength characteristic of each of the semiconductor lasers is controlled to excite the solid-state laser medium substantially uniformly in the axial direction.

The solid-state laser device according to the third aspect of the present invention is a solid-state laser in which a plurality of excitation modules each having a solid-state laser medium and a semiconductor laser for exciting the solid-state laser medium are arranged in series on an optical axis. In the apparatus, the output characteristics or the wavelength characteristics of the semiconductor laser in each of the excitation modules are controlled so that the excitation characteristics of the excitation modules substantially match.

Further, according to a fourth aspect of the present invention, in the solid-state laser device according to any one of the first to third aspects,
It has a plurality of drive systems for driving a semiconductor laser.

According to a fifth aspect of the present invention, in the solid-state laser device according to any one of the first to third aspects,
It has a plurality of cooling systems for cooling the semiconductor laser.

In the solid-state laser device according to a sixth aspect of the present invention, in any one of the first to third or fifth aspects, the oscillation wavelength of the semiconductor laser is set near the peak of the absorption spectrum of the solid-state laser medium. It is controlled so that it becomes.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. 1 is a sectional view showing a solid-state laser device according to Embodiment 1 of the present invention. FIG. 1A is a sectional view in the optical axis direction of an LD pumping module, that is, a longitudinal section, and FIG. A cross section in a direction perpendicular to FIG. In FIG. 1, 1 is a solid-state laser medium, 10, 11, 12, and 13 are semiconductor lasers (L
D), 3 is a flow tube, 4 is a condenser, 5 is an optical waveguide optical element, 60, 61, 62, and 63 are LD drive systems, 7 is a cooling system, and 8 is excitation light.

The solid-state laser medium 1 is, for example, Nd: YAG
(Nd: Yttrium Aluminum Garn
et), and has the shape of a rod having a circular cross section. The solid-state laser medium 1 is provided with a flow tube 3 surrounding the solid-state laser medium 1, and a cooling medium flows between the flow tube 3 and the solid-state laser medium 1. The light collector 4 is arranged so as to surround the flow tube 3, is a diffuse reflection light collector whose inner surface is formed of a diffuse reflection surface, and has an opening. 5 is, for example, sapphire, undoped YA
G or a plate-shaped optical waveguide optical element made of optical glass having a high refractive index to the excitation light, which is installed in the opening of the condenser 4 and guides the excitation light 8 into the condenser. LD10,
11, 12 and 13 are arranged symmetrically in a cross section perpendicular to the axis of the solid-state laser medium 1, and the excitation light 8 emitted from the light emitting section
The light emitting portion is fixed at a position close to the end face of the optical waveguide optical element 5 so that the light is introduced from the end face of the optical waveguide optical element 5 with almost no loss. LD10, 11, 12, 13
Is cooled by a cooling system 7 having a temperature control function.
The cooling system 7 includes, for example, a cooling medium circulating apparatus having a temperature control function, a cooling medium flow path, and a cooling medium.
D is like being cooled. LD10, 1
1, 12 and 13 are respectively connected to a power supply, and are separately driven by independent LD drive systems 60, 61, 62 and 63 including this power supply.

In the LD-pumped solid-state laser device configured as described above, a cooling medium controlled at a preset temperature is passed through the LDs 10, 11, 12, and 13 and the solid-state laser medium 1, and the LD drive system 60 , 61, 62, 6
When a current is separately supplied to each of the LDs 10, 11, 12, and 13 according to 3, the solid-state laser medium 1 is excited from the side by the excitation light 8 and becomes a laser amplification medium for amplifying a laser beam.

The value of the current flowing through the LDs 10, 11, 12, 13 is determined as follows, for example. That is, the LDs usually have variations, and not all LDs have the same output with the same drive current, and the drive currents with the same output differ for each LD. Therefore, first, the relationship between the drive current of the LD and the output of the pumping light from the LD is obtained by measurement. At this time, the temperature of the cooling medium flowing through the LD is set to the same temperature as when the laser is used as a laser device. From the relationship between the outputs of all the LDs arranged in the same cross section perpendicular to the optical axis and the drive current, a drive current value is determined for each LD such that the outputs of these LDs are substantially the same. In the first embodiment, a plurality of L
Since each LD can be driven independently using the D drive system, the drive current value can be set individually and the output of each LD can be made uniform.

FIG. 2 is a diagram showing an excitation intensity distribution in a cross section perpendicular to the axis of the solid-state laser medium 1. In the case where each LD is driven by an individual drive current value so that the output of each LD becomes almost the same. (Embodiment 1) and a case where each LD is driven by the same drive current value (Comparative Example). In FIG. 2, the solid line indicates the excitation intensity distribution according to the first embodiment, and the broken line indicates the excitation intensity distribution according to the comparative example. In the comparative example, since the outputs of the LDs do not match, the excitation intensity on the LD side with the higher output becomes relatively high, and the excitation intensity in the solid-state laser medium becomes non-uniform. As a result, the temperature distribution of the solid-state laser medium 1 does not have axial symmetry, and the optical axis of the obtained laser beam is decentered from the axis of the solid-state laser medium, causing a problem that a sufficient output cannot be obtained. In addition, there is a problem that the shape of the laser beam is distorted and a high-quality laser beam cannot be obtained. On the other hand, in the first embodiment, since the output of the LD is adjusted, it is excited isotropically, and there is no problem that the optical axis is decentered, and high-output laser oscillation can be performed. Further, the laser beam also has a shape with good roundness, and a high-quality laser beam can be obtained.

In this embodiment, one LD drive system is provided for one LD. However, as shown in FIG. 3, the same LD drive system is applied to a plurality of LDs having similar output characteristics. It may be operated using a system. In this case, the same L
The arrangement position of the LDs operated by the D drive system does not need to be opposed as shown in FIG. 3, and may be freely determined.

In the first embodiment, four LDs are arranged on the side surface of the solid-state laser medium, and the output of each LD is adjusted to excite the LD isotropically. The number is not limited to four, but may be two or more, and the arrangement position may be freely determined within a range where the excitation light of each LD enters the solid-state laser medium. Also in this case, if the output of each LD is adjusted to excite the solid-state laser medium isotropically, the same effect as in the above embodiment can be obtained.

Embodiment 2 FIG. FIG. 4 is a sectional configuration diagram showing a solid-state laser device according to Embodiment 2 of the present invention.
3 shows a longitudinal section of a D excitation module. In the second embodiment, the LDs are arranged in two stages along the axis of the solid-state laser medium 1. LDs 10, 11, 1 arranged in the first stage
2 and 13 (only LDs 10 and 12 are shown) are LD drive systems 60
And the LDs 14, 15, 16, 1
7 (only the LDs 14 and 16 are shown) is connected to the LD drive system 61 and is driven independently for each stage.

As in the first embodiment, the relationship between the laser output of each LD and the drive current value is determined by measurement, and the sum of the laser outputs of the LDs 10, 11, 12, and 13 constituting the first stage and the second stage. The current values of the LD drive system 60 and the LD drive system 61 are set so that the sum of the laser outputs of the LDs 14, 15, 16, and 17 constituting the eyes becomes substantially equal. As a result, the excitation intensity in the optical axis direction becomes uniform.

FIGS. 5A and 5B show the Gaussian beam diameter determined in the resonator when a laser resonator having a total reflection mirror and a partial transmission mirror is formed, with respect to the sum of the excitation intensities. FIG. 5A shows a case where the current values of the LD drive system 60 and the LD drive system 61 are the same (comparative example), and FIG. 5B shows a case where the LD drive system 60 and the LD drive system 61 have the same current value. This is a case where the current value is set so that the sum of the laser outputs of the respective stages becomes equal (Embodiment 2). In FIG. 5, a region where the Gaussian beam diameter is finite is a stable operation range in which laser oscillation can be stably performed. In the comparative example,
Since the excitation intensity in the optical axis direction is not set to be uniform and is not uniform, the stable operation range is divided into two, and stable laser oscillation is not established between the two stable operation ranges. There is a stable region. This means that when laser oscillation is performed by changing the excitation intensity, there is a point where laser oscillation is unstable or laser oscillation cannot be performed, and there is a problem in practical use of the laser oscillator. Also,
Since the excitation intensity cannot be set arbitrarily, there is a problem that the output from the oscillator cannot be arbitrarily selected. On the other hand, in the second embodiment, a plurality of LD drive systems are provided for a set of a plurality of stages of LDs arranged along the axis of the solid-state laser medium so that the excitation intensity in the optical axis direction is made uniform. Therefore, stable laser oscillation including no unstable region can be performed.

In the second embodiment, the LDs are arranged in two stages along the axis of the solid-state laser medium. However, two or more LDs may be arranged. In the case of a configuration having three or more stages, a plurality of LDs having similar characteristics may be driven using the same LD drive system.

Further, in the second embodiment, the relative positional relationship between the plurality of LDs constituting each stage has been described as being parallelly moved along the axis, but the LD is moved while being rotated about the axis. It may be configured.

Furthermore, in the second embodiment, the number of LDs constituting each stage is four, but the number of LDs constituting each stage, that is, the number of LDs in a cross section perpendicular to the optical axis is shown. The number of arrangement may be one or more, and the arrangement position is LD
May be freely determined within a range in which the excitation light is incident on the solid-state laser medium.

In the second embodiment, one LD drive system is provided for each stage in which a plurality of LDs are arranged, and a plurality of LDs constituting each stage are driven with the same current value. However, two or more LD drive systems may be used for each stage. In this case, similarly to the first embodiment, by controlling each of the LD driving systems so that the excitation intensity in a cross section perpendicular to the optical axis becomes uniform, a high-output, high-quality laser beam can be obtained. More stable laser oscillation can be performed.

Further, in the second embodiment, the characteristics of the plurality of LDs constituting each stage are not limited at all. However, as the LDs constituting each stage, LDs having output characteristics close to each other are collected. The step may be configured so that the excitation intensity in a section perpendicular to the optical axis is substantially uniform. In this way, a high-output and high-quality laser beam can be obtained, and more stable laser oscillation can be performed.

Embodiment 3 FIG. 6 is a sectional view showing a solid-state laser device according to Embodiment 3 of the present invention.
3 shows a longitudinal section of a D excitation module. In FIG. 6, 90
Represents the solid-state laser medium 1 with LDs 10, 11, 12, 13 (L
LD pumping module for pumping the solid-state laser medium 1 with LDs 14, 15, 1
L excited by 6, 17 (only LD14, 16 are shown)
D excitation module. In the third embodiment, two LD excitation modules 90 and 91 are arranged along the optical axis. The LD excitation modules 90 and 91 are driven by LD drive systems 60 and 61, respectively, and the LDs are driven so that the excitation intensities of the two LD excitation modules 90 and 91 are substantially equal.
The drive currents of the drive systems 60 and 61 are adjusted.

In the third embodiment, since the LD drive systems 60 and 61 are provided for each of the LD excitation modules 90 and 91, a plurality of LDs arranged along the optical axis direction are provided.
The excitation intensity of the excitation modules can be made uniform, and stable laser oscillation without an unstable region can be performed as in the second embodiment.

In the third embodiment, the configuration using two LD excitation modules has been described. However, the number is not limited to this, and it is sufficient if the number is two or more. Further, in the case of a configuration of three or more, a plurality of LD excitation modules having the same excitation characteristics are used for a plurality of LD excitation modules using the same LD drive system.
The D excitation module may be driven.

In the third embodiment, the configuration in which four LDs are arranged on the side surface of the solid-state laser medium has been described.
The number of LDs constituting the D pumping module may be one or more, and the arrangement position thereof may be freely determined within a range where the pumping light of the LD enters the solid-state laser medium. Also,
Each LD may be driven by a plurality of LD drive systems. In this case, as in Embodiments 1 and 2, if each LD drive system is controlled so that the excitation intensity in a section perpendicular to the optical axis or the excitation intensity in the optical axis direction becomes uniform, high output and high output can be achieved. A high-quality laser beam can be obtained, and more stable laser oscillation can be performed.

Further, one LD excitation module may be constituted by a plurality of LDs having close output characteristics, and each LD excitation module may be constituted so that the excitation intensity in a section perpendicular to the optical axis is substantially uniform. . If you do this,
A high-output, high-quality laser beam can be obtained, and more stable laser oscillation can be performed.

Embodiment 4 FIG. 7 is a sectional view showing a solid-state laser device according to Embodiment 4 of the present invention.
3 shows a cross section of a D excitation module. In the fourth embodiment, a plurality of LDs are provided in a section perpendicular to the axis of the solid-state laser medium 1.
10, 11, 12, 13 are arranged symmetrically, and the cooling system 7
0, 71, 72, 73 correspond to the LDs 10, 11, 12, 1,
3 are provided as independent systems. Also, L
D10 and LD11 are driven by an LD drive system 60, and LD12 and LD13 are driven by an LD drive system 61.

First, the relationship between the cooling temperatures of the LDs 10, 11, 12, and 13 and the oscillation wavelength is obtained by measurement. FIG. 8 shows an example of the relationship between the cooling temperature and the oscillation wavelength in each LD. The temperature of the cooling medium for each LD is determined so that the oscillation wavelength of the LD becomes substantially equal at the current value for driving each LD. In the fourth embodiment, the cooling system of each LD is provided independently for a plurality of LDs constituting the LD pumped solid-state laser device, so that the temperature of the cooling medium of the LD can be controlled individually. . As a result, as described above, control can be performed so that the oscillation wavelengths of the LDs are substantially equal.

FIG. 9 shows an absorption spectrum of Nd: YAG as an example of an absorption spectrum of the solid-state laser medium. As described above, when the oscillation wavelength of the LD is different, the absorption rate of the LD excitation light in the solid-state laser medium is different, and the excitation efficiency and the excitation density distribution are changed. FIG. 10 shows a solid-state laser medium 1
It is a diagram showing the excitation intensity distribution in a cross section perpendicular to the optical axis of,
When the temperature of the cooling medium of each LD is controlled so that the oscillation wavelength of each LD becomes substantially the same (Embodiment 4),
Is cooled by a cooling medium of the same temperature (Comparative Example). In FIG. 10, a solid line indicates an excitation intensity distribution according to the fourth embodiment, and a broken line indicates an excitation intensity distribution according to a comparative example. In the comparative example, since the oscillation wavelengths of the opposing LDs are different, the excitation in the solid-state laser medium is not uniform.
In the fourth embodiment, since the oscillation wavelengths of the LDs are aligned, isotropic and uniform excitation is achieved. Therefore, high-power laser oscillation can be performed without decentering the optical axis. Further, the laser beam also has a shape with good roundness, and a high-quality laser beam can be obtained.

As described above, according to the fourth embodiment,
Since a cooling system is provided for each of the plurality of LDs and the oscillation wavelength of each LD is adjusted, a section perpendicular to the axis of the solid-state laser medium can be excited isotropically, and high-quality laser oscillation can be performed with high output. be able to.

In the fourth embodiment, one LD
However, the same cooling system may be used for a plurality of LDs having similar wavelength characteristics.

In the fourth embodiment, four LDs are arranged on the side surface of the solid-state laser medium. However, the number of LDs is not limited to this number, and may be two or more.
Further, the arrangement position may be freely determined within a range where the excitation light of each LD is incident on the solid-state laser medium. Also in this case, if the temperature of the cooling medium of each LD is controlled to adjust the oscillation wavelength of the LD so as to excite the solid-state laser medium isotropically, the same effects as in the above embodiment can be obtained.

In the above embodiment, as shown in FIG. 7, the LD 10 and the LD 11 are driven by the LD drive system 60, and the LD 12 and the LD 13 are driven by the LD drive system 61, as in the first embodiment. And each LD is a separate L
It may be independently driven by the D drive system. In this case, if a current is supplied to each LD drive system so that the output of each LD becomes substantially the same, the excitation intensity in a cross section perpendicular to the optical axis becomes more uniform, and a high-output and high-quality laser beam can be obtained. effective. At this time, a plurality of Ls having similar output characteristics
For D, the same effect is obtained even if the same drive system is used.

Embodiment 5 FIG. FIG. 11 is a sectional view showing a solid-state laser device according to Embodiment 5 of the present invention.
3 shows a longitudinal section of an LD excitation module. In the fifth embodiment, the LDs are arranged in two stages along the axis of the solid-state laser medium 1. LDs 10, 11, 1 arranged in the first stage
2 and 13 (only the LDs 10 and 12 are shown) are connected to the cooling system 70, and the LDs 14, 15, 16, and 17 arranged in the second stage
(Only the LDs 14 and 16 are shown) is connected to the cooling system 71 and is cooled independently for each stage. Also, the first stage and 2
Each LD in the stage is driven by the LD drive system 6.

As in the fourth embodiment, the relationship between the oscillation wavelength of each LD and the temperature of the cooling medium is obtained by measurement, and the oscillation wavelength of each of the LDs 10, 11, 12, and 13 constituting the first stage is determined by the following equation.
The temperature of the cooling medium of the cooling system 70 and the cooling medium of the cooling system 71 is determined so that the oscillation wavelengths of the LDs 14, 15, 16, and 17 constituting the stage are substantially equal.

In the fifth embodiment, different cooling systems are provided for the two stages of LDs arranged along the optical axis, so that the LD cooling temperature can be set for each stage. As a result, the solid-state laser medium can be excited uniformly in the optical axis direction, so that stable laser oscillation can be performed as in the second embodiment.

In the above embodiment, the configuration in which the LDs are arranged in two stages along the axis has been described, but two or more LDs may be arranged.
In the case of a configuration having three or more stages, the LDs in a plurality of stages having similar wavelength characteristics may be cooled using the same cooling system.

Further, in the fifth embodiment, the relative positional relationship between the plurality of LDs constituting each stage has been described as a configuration in which the LD is translated along the axis, but the LD is moved while being rotated about the axis. It may be configured.

Further, in the fifth embodiment, the number of LDs constituting each stage is four. However, the number of LDs constituting each stage may be one or more. The position may be freely determined within a range where the pumping light of the LD enters the solid-state laser medium.

In the fifth embodiment, one cooling system is provided for each stage in which a plurality of LDs are arranged. However, as in the fourth embodiment, a plurality of cooling systems are provided in each stage. You may. In this case, similarly to the fourth embodiment, by controlling each of the cooling systems so that the excitation intensity in a cross section perpendicular to the optical axis becomes uniform, a high-output and high-quality laser beam can be obtained, and It is possible to perform stable laser oscillation.

In the fifth embodiment, the characteristics of the plurality of LDs constituting each stage are not limited at all. However, as the LDs constituting each stage, LDs having wavelength characteristics close to each other are collected, and The step may be configured so that the excitation intensity in a section perpendicular to the optical axis is substantially uniform. In this way, a high-output and high-quality laser beam can be obtained, and more stable laser oscillation can be performed.

Further, in the fifth embodiment, FIG.
As shown in FIG. 1, the first-stage LDs 10, 11, 12, 13
And the second-stage LDs 14, 15, 16, and 17 are the LD drive system 6
, But as in the first embodiment, each L
D may be independently driven by separate LD drive systems.
In this case, the output of each LD is almost the same.
When a current is applied to the drive system, the excitation intensity in the optical axis direction and in the cross section perpendicular to the optical axis becomes more uniform, and there is an effect that a high-output and high-quality laser beam can be obtained. In this case, the same effect can be obtained for a plurality of LDs having similar output characteristics even if the same drive system is used.

Embodiment 6 FIG. FIG. 12 is a sectional configuration diagram showing a solid-state laser device according to Embodiment 6 of the present invention.
3 shows a longitudinal section of an LD excitation module. Embodiment 6
Is one in which two LD excitation modules are arranged along the optical axis. The LD excitation modules 90 and 91 are cooled by cooling units 70 and 71, respectively, and the cooling temperatures are set so that the oscillation wavelengths of the two LD excitation modules 90 and 91 are equal to each other.

In the sixth embodiment, since the cooling systems 70 and 71 are provided for each of the LD excitation modules 90 and 91, respectively, the oscillation wavelength of the LD in the plurality of LD excitation modules arranged along the optical axis direction. Can be adjusted for each LD
The excitation intensity distribution of the excitation module can be made uniform.
Therefore, similarly to the fifth embodiment, stable laser oscillation can be performed.

In the sixth embodiment, the configuration using two LD excitation modules has been described. However, the number of LD excitation modules is not limited to this, and may be two or more. In the case of a configuration of three or more units, a plurality of LD excitation modules having similar excitation characteristics may be cooled using the same cooling system.

Further, one LD excitation module may be constituted by a plurality of LDs, and each LD may be cooled by a plurality of cooling systems. In this case, as in Embodiment 4, if each cooling system is controlled so that the excitation intensity in a section perpendicular to the optical axis becomes uniform, a high-output and high-quality laser beam can be obtained and more stable. Laser oscillation can be performed.

One LD excitation module may be composed of a plurality of LDs having similar wavelength characteristics, and each LD excitation module may be configured so that the excitation intensity in a section perpendicular to the optical axis is substantially uniform. . If you do this,
A high-output, high-quality laser beam can be obtained, and more stable laser oscillation can be performed.

Further, in the sixth embodiment, FIG.
As shown in FIG. 2, the LDs of the first and second LD excitation modules are both driven by the LD drive system 6, but each LD may be independently driven by a separate LD drive system. In this case, if current is supplied to each LD drive system so that the output of each LD becomes substantially the same, the excitation intensity in the optical axis direction becomes more uniform, and there is an effect that a high-output and high-quality laser beam can be obtained. Further, the number of LDs constituting each LD pumping module may be one or more, and the arrangement position may be freely determined within a range where the pumping light of the LD is incident on the solid-state laser medium. In addition, each LD has a plurality of L
It may be driven by a D drive system. In this case, as in Embodiments 1 and 2, if each LD drive system is controlled such that the excitation intensity in a section perpendicular to the optical axis or the excitation intensity in the optical axis direction becomes uniform, high output can be obtained.
A high-quality laser beam can be obtained, and more stable laser oscillation can be performed.

Embodiment 7 FIG. Embodiment 7 is different from Embodiments 4 to 6 in that the oscillation wavelength of the LD coincides with the peak of the absorption spectrum of the solid-state laser medium.
This is for setting the cooling temperature of the LD. For example, in the case of a solid-state laser medium having an absorption spectrum shown in FIG.
If the cooling temperature of the LD is set so that the oscillation wavelength of the laser beam becomes 808 nm, the solid-state laser medium can be excited with high efficiency because the absorptance of the excitation light at the above wavelength is high.

It should be noted that the oscillation wavelength does not necessarily need to be exactly coincident with the peak of the absorption spectrum, but may be coincident with the vicinity of the peak.

In each of the above embodiments, the solid-state laser device using the diffuse reflection concentrator is shown. However, it is not always necessary to provide the diffuse reflection concentrator. May be provided, and a light collector may not be provided.

When the solid-state laser device shown in each of the above embodiments is used as an amplifier, it is possible to perform isotropic amplification without beam distortion and obtain an efficient device.

[0060]

As described above, according to the solid-state laser device of the first configuration of the present invention, a plurality of semiconductor lasers are arranged in a cross section perpendicular to the axis of the solid-state laser medium, and In the apparatus for exciting the solid-state laser medium, the output characteristics or wavelength characteristics of each of the semiconductor lasers are controlled to excite the solid-state laser medium almost uniformly in a cross section perpendicular to the axis. A solid-state laser device that generates a laser beam with high output can be obtained.

Further, according to the solid-state laser device of the second configuration of the present invention, a plurality of semiconductor lasers are arranged along the axial direction of the solid-state laser medium, and the solid-state laser medium is excited by the light of the semiconductor laser. In the device, the output characteristics or wavelength characteristics of each of the semiconductor lasers are controlled to excite the solid-state laser medium substantially uniformly in the axial direction, so that a solid-state laser device that stably generates a laser beam can be obtained. it can.

Further, according to the solid-state laser device of the third configuration of the present invention, a plurality of excitation modules each having a solid-state laser medium and a semiconductor laser for exciting the solid-state laser medium are arranged in series on the optical axis. In the solid-state laser device, the output characteristics or the wavelength characteristics of the semiconductor laser in each excitation module are controlled so that the excitation characteristics of the excitation modules are substantially matched, so that a solid-state laser device that stably generates a laser beam is obtained. Can be.

According to the solid-state laser device of the fourth configuration of the present invention, in any one of the first to third configurations, a plurality of driving systems for driving the semiconductor laser are provided. Can be controlled, and the solid-state laser medium can be excited uniformly.

According to the solid-state laser device of the fifth configuration of the present invention, in any one of the first to third configurations, a plurality of cooling systems for cooling the semiconductor laser are provided. Can be controlled, and the solid-state laser medium can be excited uniformly.

Further, according to the solid-state laser device of the sixth configuration of the present invention, in any one of the first to third or fifth configurations, the oscillation wavelength of the semiconductor laser is adjusted to the peak of the absorption spectrum of the solid-state laser medium. Since the control is performed so as to be in the vicinity, the solid-state laser medium can be excited with high efficiency.

[Brief description of the drawings]

FIG. 1 is a sectional configuration diagram showing a solid-state laser device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation of the solid-state laser device according to the first embodiment of the present invention.

FIG. 3 is a sectional configuration diagram showing another solid-state laser device according to Embodiment 1 of the present invention;

FIG. 4 is a sectional configuration diagram showing a solid-state laser device according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating an operation of the solid-state laser device according to the second embodiment of the present invention.

FIG. 6 is a sectional configuration diagram showing a solid-state laser device according to a third embodiment of the present invention.

FIG. 7 is a sectional configuration diagram showing a solid-state laser device according to a fourth embodiment of the present invention.

FIG. 8 is a diagram illustrating an operation of a solid-state laser device according to a fourth embodiment of the present invention.

FIG. 9 is a diagram illustrating an operation of a solid-state laser device according to a fourth embodiment of the present invention.

FIG. 10 is a diagram illustrating an operation of a solid-state laser device according to a fourth embodiment of the present invention.

FIG. 11 is a sectional configuration diagram showing a solid-state laser device according to a fifth embodiment of the present invention.

FIG. 12 is a sectional configuration diagram showing a solid-state laser device according to Embodiment 6 of the present invention.

FIG. 13 is a sectional view showing a conventional solid-state laser device.

[Explanation of symbols]

1,21 solid-state laser medium, 10,11,12,13,
14, 15, 16, 17, 28 semiconductor laser (L
D), 3 flow tubes, 4 condensers, 5 optical waveguide elements, 6, 60, 61, 62, 63 LD drive system, 7, 7
0, 71, 72, 73 cooling system, 8 excitation light, 90, 9
1 LD excitation module, 22 Cooling sleeve, 23
Heat sink, 24 waveguide, 25 holding member, 26
Mounting holes, 27 holders, 29 cooling passages.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shuichi Fujikawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 5F072 AB02 AK01 FF09 GG09 JJ02 JJ04 JJ20 KK30 PP07 RR01 TT15 TT29 5F073 BA09 EA03 EA15 EA29 GA21 GA38

Claims (6)

[Claims] 1. A semiconductor laser comprising: a plurality of semiconductor lasers arranged in a cross section perpendicular to an axis of a solid-state laser medium; and the solid-state laser medium is excited by light from the semiconductor laser. , And the solid-state laser medium is excited almost uniformly in a cross section perpendicular to the axis. 2. An apparatus in which a plurality of semiconductor lasers are arranged along an axial direction of a solid-state laser medium, and wherein the solid-state laser medium is excited by light of the semiconductor laser, wherein output characteristics or wavelength characteristics of each of the semiconductor lasers are controlled. A solid-state laser device characterized in that the solid-state laser medium is excited almost uniformly in the axial direction. 3. A solid-state laser device comprising: a plurality of excitation modules each having a solid-state laser medium and a semiconductor laser that excites the solid-state laser medium;
A solid-state laser device wherein output characteristics or wavelength characteristics of the semiconductor laser in each pump module are controlled so that the pump modules have substantially the same pump characteristics. 4. The solid-state laser device according to claim 1, further comprising a plurality of driving systems for driving a semiconductor laser. 5. The solid-state laser device according to claim 1, further comprising a plurality of cooling systems for cooling the semiconductor laser. 6. The solid-state laser device according to claim 1, wherein an oscillation wavelength of the semiconductor laser is controlled to be near a peak of an absorption spectrum of the solid-state laser medium.