JP3436286B2 - Substitution-type garnet crystal materials for solid-state lasers - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state laser crystal material used as a pumping light source for an optical amplifier used in the field of optical communication.

[0002]

In the field of optical communication, as a signal for optical communication,
Light in the wavelength band of 1.3 μm and light in the wavelength band of 1.55 μm are used. The signal light is transmitted using an optical fiber, but if the signal light propagates for about 50 km or more, it is inevitable that the loss during that time cannot be ignored and the intensity gradually decreases. Therefore, it is necessary to amplify the optical signal during transmission, but it is desirable to directly amplify the optical signal in order to transmit information at an ultrahigh speed. At that time, an optical amplifier is required.

Among optical amplifiers, 1.3 μm is required in the 1.3 μm band, which is the wavelength range for subscribers.
An optical amplifier for a band, which decomposes trivalent praseodymium ion which is a rare earth element in a fluoride optical fiber and uses its stimulated emission to amplify light, is promising and is under development. There is.

FIG . 7 is an energy diagram of praseodymium. In the figure, a is excitation light, b is laser light, c is level ³ H ₄ , d is level ³ H ₅ , and e is level ³ H.
₆ , f is the level ³ F ₂ , g is the level ³ F ₃ , and h is the level
³ F ₄ and i represent the level ¹ G ₄ . In the 1.3 μm band optical amplifier, ³ H ₄ having a center wavelength of about 1.02 μm is used.
→ Absorbs light using the transition of ¹ G ₄ and the center wavelength is 1.
It is characterized in that signal light in the 1.3 μm band is amplified by utilizing stimulated emission of 30 μm of ¹ G ₄ → ³ H ₅ .

The 1.3 μm band optical amplifier requires an external light source of 1.02 μm wavelength for exciting praseodymium ions. As the external excitation light source, a device that has a high output, a stable oscillation wavelength, a long life, a low price and a small size is desirable. Further, in the 1.55 μm band optical amplifier, optical amplification is performed by stimulated emission of erbium ions dispersed in a quartz optical fiber, but an external excitation light source of 0.98 μm wavelength is used for optical absorption of erbium ions. ing. As an external excitation light source, it is quite the same that a high output, stable oscillation wavelength, long life, low cost and small size element are desirable.

The InGaAs semiconductor laser diode is being developed to satisfy these requirements. However, InGaAs semiconductor laser diodes
Regarding the wavelengths of 1.02 μm and 0.98 μm, there is still a problem in the stability of the oscillation wavelength, and the mass production system has not been improved yet, and the unit price is increasing. In addition, there is a problem in practical use that the operating life is short. Another problem is that an optical isolator is required to stabilize the oscillation wavelength.

The optical isolator is used to block the reflected return light of the light emitted from the semiconductor laser. This is to prevent the reflected wavelength of the reflected light from being amplified again in the resonator of the semiconductor laser so that the oscillation wavelength becomes unstable due to the influence of the light having different phases. However, as the isolator for the light in the vicinity of 1 μm, the magnetic garnet material used for the isolator for the communication wavelength (1.3 μm or 1.55 μm) causes a large loss. Therefore, a special semiconductor material such as HgCdMnTe is used. Although it is manufactured using this material, it is difficult to grow a large crystal, and if the composition deviates even a little, the characteristics are extremely changed, so that it is difficult to manufacture and the material is very expensive.

On the other hand, solid-state lasers have good wavelength stability. For example, titanium sapphire laser
It is known as a solid-state laser capable of changing the wavelength in the range of 0.7 to 1.1 μm, and is widely used at the laboratory level. At the experimental stage, titanium sapphire laser may be used to investigate the characteristics of the optical fiber for the optical amplifier, but there are the following problems in using it for a practical amplifier.

First, an argon gas laser is usually used to excite a titanium sapphire laser. Therefore, the entire laser becomes extremely large. And it can be very expensive. As a candidate that can solve these problems, a solid-state laser that can be excited by an existing inexpensive, stable, and high-power semiconductor laser is considered. At present, one of the candidates is expected to be Yb:
It is a YAG laser. Yb: Y ₃ Al ₅ O ₁₂ (Yb:
The YAG) laser is a promising laser recently confirmed to have room temperature continuous oscillation at 1.03 μm.
External excitation light of 0.943 or 0.968 μm that satisfies the light absorption of ytterbium ions is required. Such external pumping light is a choice between using the tunable solid-state laser described above or using a special semiconductor laser. The tunable solid-state laser has the above-mentioned problems and cannot withstand the demand for small size and low cost. Further, if a semiconductor laser having a special wavelength is used for pumping, it is more advantageous to use a semiconductor laser having a desired wavelength range from the beginning, and there is no problem. Further, the Yb: YAG laser has an oscillation threshold of 300.
It is as large as mW, and has not reached the point where it can be put to practical use.

As described above, in the conventional type laser,
To be used practically as an external excitation light source for optical amplification,
There were many issues.

[0011]

As described above, the conventional solid-state laser can be excited by an existing semiconductor laser which is inexpensive and can easily obtain a high output, and has an emission wavelength of 0.98 μm.
There was no solid-state laser in the range of m to 1.03 μm, in which oscillation was not unstable due to external disturbance such as returning light.

Therefore, an object of the present invention is to produce AlGa oscillating at an existing wavelength of 0.8 μm that is inexpensive and can easily obtain high output.
Can be excited by an As semiconductor laser and has an oscillation wavelength of 0.98
It is intended to provide a material for a solid-state laser which is in the range of μm to 1.04 μm and whose oscillation does not become unstable due to external disturbance such as returning light.

[0013]

[Means for Solving the Problems]
Because, the solid body laser for substituted garnet crystal materials, general formula is represented by _R 3 _A 5 _{O 12, R} is yttrium, lanthanum, cerium, praseodymium, neodymium, samarium,
It consists of any combination of one or more elements selected from europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and bismuth, and A is selected from aluminum, scandium and gallium. At least neodymium and ytterbium in a substitutional garnet crystal composed of an arbitrary combination of one or more selected elements.
It is characterized by containing bium as its constituent element.

That is, 0.98 μm to 1.04 μm
Providing a solid-state laser material for practical excitation light source in the wavelength region, a substituted garnet crystal material obtained by substituting a combination of some as neodymium and ytterbium of the rare earth element constituting the garnet crystal toward To do.

Further, in the substitutional garnet crystal material of the present invention , the occupancy of neodymium is 1 of the whole rare earth element.
% Or more, and the occupancy of ytterbium is preferably 40% or less of the whole rare earth elements.

Further, neodymium, Itterubiu beam other than the rare earth element is, for lanthanum, gadolinium, is that any combination of one or more elements selected from among yttrium desirable.

[0017]

The garnet crystal is represented by the general formula R ₃ A ₅ O ₁₂ , and it is possible to substitute the R portion with a rare earth element and the A portion with aluminum, scandium or gallium. In the present invention, in the composition of various substitution type garnet crystals that have been subjected to such substitution, a part of R is further substituted with another rare earth element such as neodymium, and a part of A is substituted with aluminum, scandium and gallium, respectively. It is possible to In the present invention, among the compositions of various substitution type garnet crystals having such substitution, R
Using substituted garnet crystal material comprising of the combination of ne Ojiumu and ytterbium part as a condition of必<br/> mandatory.

The energy level of the substituting element causes splitting when a field created by a neighboring atom or atomic group is sensed. The field is called a ligand field, which is determined by changing the crystal system of the host. The quantum field changes, and the energy level of the substituting element shifts by an amount corresponding to the property of the energy level. Therefore, the oscillation wavelength can be shifted within a certain range by appropriately selecting the crystal system of the host. For example, in a garnet crystal, the ligand field greatly changes depending on whether A is mostly aluminum or gallium. Therefore, for light in the vicinity of 1 μm, 0.98 μm to 1.04 μ is sufficient.
It is possible to select the oscillation wavelength within the range of m.

Furthermore, the absorption wavelengths can be set to some extent by absorption based on a plurality of substitutional elements, and further, the absorbed energy can cause internal conversion between the same atoms,
By utilizing quantum mechanical interaction such as intersystem crossing that occurs between different atoms, it can be successfully distributed to the oscillating upper level of the light emitting atom, and inversion distribution between the oscillating levels can be created.

Since the substitutional garnet crystal material for solid-state laser according to the present invention contains neodymium as a rare earth element, the absorption transition from the ground level to ⁴ F _5/2 results in inexpensive 0.81 μm wavelength AlGaAs. are possible excitation with a semiconductor laser, there is energy transfer by automatic non-emission of the trivalent ytterbium ions by dipole-dipole interactions from the transition to the neodymium ions in the non-emission to the ⁴ F _3/2 level , ² F of Itterubiu Ion
_A population inversion can be formed to carry out stimulated emission near 1 μm in the _5/2 level.

By appropriately selecting the constituent ratio of gallium, aluminum and scandium which are the constituent elements of A, it is possible to selectively oscillate at a desired wavelength within the range of 0.98 μm to 1.04 μm. In conventional garnet crystals for solid-state lasers that use neodymium as the active ion, the content of neodymium should be set to the whole rare earth in order to avoid concentration quenching caused by increasing the content of neodymium ion in consideration of absorption / emission efficiency. It was selected around 1%. However, the role of the neodymium ions of the present invention is not to deviate situation emits light, and efficiently absorb the excitation light of 0.81 .mu.m, it is to transfer energy to the ytterbium ions near. That is, it is preferable that the content is not less than the level at which light emission is unlikely to occur, and the content of the rare earth element is 1
% Or more is selected.

The present invention is based on the above.
It is possible to provide a substitutional garnet crystal material for a solid-state laser, which has an oscillation wavelength in the wavelength range of m to 1.04 μm.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0024]

Example 1 Examples 1-1 to 1-5 shown below
Then, a bulk single crystal of the substitutional garnet crystal material for a solid-state laser of the present invention was produced by the Czochralski method. Furthermore, the bulk single crystal has a flat surface on one side in order to evaluate characteristics as a laser material,
One side was processed into a spherical surface having a radius of 5 cm and a disk having a thickness of 1.5 mm, and at a wavelength of 0.98 to 1.04 μm, a flat surface was coated with a reflectance of about 99%, and a spherical surface was coated with a reflectance of about 97%. FIG. 1 shows a measurement system for evaluating the characteristics of the substitutional garnet crystal materials for solid-state lasers of Examples 1-1 to 1-9 according to the present invention as a laser material. An AlGaAs semiconductor laser having a wavelength of 0.808 μm was used as the excitation light source.
The excitation light 3 emitted from the semiconductor laser 1 is coupled to the lens 2,
While converging through 2 ′ and 2 ″, it is incident on the disk 4 of the substitutional garnet crystal material for solid-state laser of Examples 1-1 to 1-9 , and the light 5 emitted from the disk 4 is reflected by the optical spectrum analyzer 6. The laser oscillation characteristics were evaluated by observing.

[0025]

Example 1-1 In this example, as shown in Example 1, the composition formula R _3-XY Nd _X Yb _Y A _5-Z Ga _Z O _{12 was used.}
And R _3-X-Y Nd _X Yb _Y A1 _5-Z-W A2 _W
Ga _Z O ₁₂ (X = 0.13, Y = 0.80, Z = 0.
17, W = 2.0, A and A1 are Al, A2 is Sc,
R is La, Ce, Pr, Bi, Sm, Eu, Gd, T
b, Dy, Ho, Y, Er, Tm, or any one element of Lu) of the present invention, a garnet crystal material for a laser of the present invention is produced, and laser oscillation characteristics are investigated using the measurement system shown in FIG. It was done. R, A, A1 and A2 in Table 1
Elements for which the threshold value represented by the laser oscillation wavelength of the substitutional garnet crystal material for solid-state laser of this embodiment and the light intensity of the excitation light source which is the minimum required for laser oscillation are selected are shown below. Any of the substitutional garnet crystal materials for solid-state lasers of this example lased at a wavelength in the range of 0.98 to 1.04 μm. In addition, any of the materials of this example oscillated at a threshold value of 100 mW or less, which was difficult to realize with the conventional materials.

[0026]

[Embodiment 1-2] This embodiment is the same as the first embodiment.
Composition formula _{R 3-X-Y Nd X} Yb Y A 5 O 12 , and R
_3-X-Y Nd _X Yb _Y A1 _5-W A2 _W O ₁₂ (X =
0.15, Y = 0.80, W = 2.0, A and A1 are Ga, A2 is Sc, R is La, Ce, Pr, Bi, S
m, Eu, Gd, Tb, Dy, Ho, Y, Er, Tm,
A substitutional garnet crystal material for a solid-state laser of the present invention represented by any one element of Lu) was produced, and the laser oscillation characteristics were investigated using the measurement system shown in FIG.
Table 2 shows elements for which the lasing wavelength and threshold value of the substitutional garnet crystal material for solid-state laser of the present embodiment, in which R, A, A1 and A2 are appropriately selected, are selected. Example 1
In the same manner as in -1 , any of the substitutional garnet crystal materials for solid-state lasers of this example lased at a wavelength in the range of 0.98 to 1.04 μm. In addition, any of the materials of this example oscillated at a threshold value of 100 mW or less, which was difficult to realize with the conventional materials.

[0027]

[Embodiment 1 to 3] This embodiment is similar to Embodiment 1 except that
Composition formula _{Y 3-X-Y Nd X} Yb Y Al 5 -Z Ga Z O
₁₂ (X = 0.1, Y = 1.0), a substitutional garnet crystal material for a solid-state laser of the present invention was prepared, and laser oscillation characteristics and Ga concentration Z were measured using the measurement system shown in FIG. It is a survey of relationships. FIG. 2 shows the relationship between the Ga concentration Z and the laser oscillation wavelength and oscillation threshold of the substitutional garnet crystal material for solid-state laser of this example. The lasing wavelength tends to become shorter as the Ga concentration Z increases, but any of the substitutional garnet crystal materials for solid-state lasers of this example lased at a wavelength in the range of 0.98 to 1.04 μm. In addition, although the materials of all of the present examples varied depending on the Ga concentration Z, they oscillated at a threshold value of 100 mW or less, which was difficult to realize with the conventional materials.

[0028]

[Examples 1 to 4] This example is the same as Example 1 except that
Composition formula _{Gd 3-X-Y Nd X} Yb Y Al 5-Z-W Ga
_Z Sc _W O ₁₂ (X = 0.13, Y = 1.2, W = 2.
00), a substitutional garnet crystal material for a solid-state laser of the present invention was produced, and the relationship between laser oscillation characteristics and Ga concentration Z was investigated using the measurement system shown in FIG. Figure
3 shows the relationship between the laser oscillation wavelength, the threshold, and the Ga concentration Z of the substitutional garnet crystal material for solid-state laser of this example. The laser oscillation wavelength tends to become shorter as the Ga concentration Z increases, but any of the laser garnet crystal materials of this example lased at a wavelength in the range of 0.98 to 1.04 μm. In addition, any of the materials of this embodiment is G
Although there were variations depending on the a concentration Z, oscillation occurred at a threshold value of 100 mW or less, which was difficult to realize with conventional materials.

[0029]

[Embodiment 1-5] This embodiment is similar to Embodiment 1,
Composition formula _{Y 3-X-Y-V} La V Nd X Yb Y Al 5-Z
Ga _Z O ₁₂ (X = 0.13, Y = 1.00, Z = 0.
17) A substitution type garnet crystal material for a solid-state laser of the present invention represented by 17) was produced, and the relationship between the laser oscillation characteristic and the La concentration V was investigated using the measurement system shown in FIG. Figure
4 shows the relationship between the laser oscillation wavelength, the threshold value, and the La concentration V of the substitutional garnet crystal material for solid-state laser of this example. The lasing wavelength tends to become shorter as the La concentration V increases, but any of the substitutional garnet crystal materials for solid-state lasers of this example lased at a wavelength in the range of 0.98 to 1.04 μm. Further, all the materials of the present examples oscillated at a low threshold value of 100 mW or less, which was difficult to realize with the conventional materials, although there were variations depending on the La concentration V.

In Example 1-5 , R _3-X-Y N was used.
In d _X Yb _Y A _5-Z Ga _Z O ₁₂ , R is Y and L.
Although the garnet crystal material for laser of the present invention in which a and A are Al is described, R is La, Ce, Pr, Bi, Sm,
Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Lu
Any one or more elements of A, A is one or more elements of Al or Sc, and X, Y, and Z are 0 <X.
Even within the range of <3,0 <Y <3,0 ≦ Z ≦ 5, 0.98-at a low threshold value of 100 mW or less due to the excitation of a 0.8 μm band semiconductor laser as in the case of the material of this example. 1.0
It goes without saying that laser oscillation is performed at a wavelength in the range of 4 μm.

[0031]

[Embodiment 1-6] This embodiment is similar to Embodiment 1 except that
Composition formula _{R 3-X-Y Nd X} Yb Y A 5 O 12 , and R
_3-X-Y Nd _X Yb _Y A1 _5-W A2 _W O ₁₂ (X =
0.20, Y = 0.20, W = 2.0 A and A1 is A
1, A2 is Sc, R is La, Ce, Pr, Bi, Sm,
Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Lu
Of the substitution type garnet crystal material for a solid-state laser of the present invention represented by any one of (1) to (5) and the laser oscillation characteristics were investigated using the measurement system shown in FIG. Table 3
The elements for which the lasing wavelength and the threshold value of the substitutional garnet crystal material for solid-state laser of this embodiment, in which R, A, A1 and A2 are appropriately selected, are selected are shown in FIG. Any of the substitutional garnet crystal materials for solid-state lasers of this example are 0.9.
Laser oscillation was performed at a wavelength in the range of 8 to 1.04 μm. In addition, any of the materials of this example oscillated at a low threshold value of 100 mW or less, which was difficult to realize with the conventional materials.

[0032]

[Examples 1 to 7] This example is the same as Example 1 except that
Composition formula _{R 3-X-Y Nd X} Yb Y A 5 O 12 , and R
_3-X-Y Nd _X Yb _Y A1 _5-W A2 _W O ₁₂ (X =
0.20, Y = 0.20, W = 2.0 A and A1 is A
1, A2 is Sc, R is La, Ce, Pr, Bi, Sm,
Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Lu
Of the substitution type garnet crystal material for a solid-state laser of the present invention represented by any one of (1) to (5) and the laser oscillation characteristics were investigated using the measurement system shown in FIG. Table 4
The elements for which the lasing wavelength and the threshold value of the substitutional garnet crystal material for solid-state laser of this embodiment, in which R, A, A1 and A2 are appropriately selected, are selected are shown in FIG. Any of the substitutional garnet crystal materials for solid-state lasers of this example are 0.9.
Laser oscillation was performed at a wavelength in the range of 8 to 1.04 μm. In addition, any of the materials of this example oscillated at a low threshold value of 100 mW or less, which was difficult to realize with the conventional materials.

[0033]

[Embodiment 1-8] This embodiment is similar to Embodiment 1,
Composition formula _{Y 3-X-Y Nd X} Yb Y Al 5-Z Ga Z O
₁₂ (X = 0.20, Y = 0.18), a substitutional garnet crystal material for a solid-state laser according to the present invention was produced, and FIG.
The relationship between the laser oscillation characteristic and the Ga concentration Z was investigated using the measurement system shown in FIG. FIG. 8 shows the relationship between the Ga concentration Z and the laser oscillation wavelength and oscillation threshold of the substitutional garnet crystal material for solid-state laser of this example. The lasing wavelength tends to become shorter as the Ga concentration Z increases, but any of the substitutional garnet crystal materials for solid-state lasers of this example lased at a wavelength in the range of 0.98 to 1.04 μm. In addition, although the materials of all of the present examples varied depending on the Ga concentration Z, they oscillated at a low threshold value of 100 mW or less, which was difficult to realize with the conventional materials.

[0034]

[Embodiments 1-9] This embodiment is the same as the first embodiment.
Composition formula _{Gd 3-X-Y Nd X} Yb Y Al 5-Z Ga Z O
₁₂ (X = 0.19, Y = 0.18), a substitutional garnet crystal material for a solid-state laser according to the present invention was produced, and FIG.
The relationship between the laser oscillation characteristic and the Ga concentration Z was investigated using the measurement system shown in FIG. FIG. 9 shows the relationship between the Ga concentration Z and the laser oscillation wavelength and oscillation threshold of the substitutional garnet crystal material for solid-state laser of this example. The lasing wavelength tends to become shorter as the Ga concentration Z increases, but any of the substitutional garnet crystal materials for solid-state lasers of this example lased at a wavelength in the range of 0.98 to 1.04 μm. In addition, although the materials of all of the present examples varied depending on the Ga concentration Z, they oscillated at a low threshold value of 100 mW or less, which was difficult to realize with the conventional materials.

[0035]

[Embodiment 2] Embodiment 2 1 shown below, was prepared an optical waveguide having a core portion made of substituted garnet crystal material for a solid laser according to the present invention as shown in FIG. Figure 5
The optical waveguide shown in FIG. ₃ is a liquid phase epitaxial growth method (LPE method) using PbO and B ₂ O ₃ as a flux on a substrate 9 made of Y ₃ Al ₅ O ₁₂ (YAG).
Thus, a layer made of the substitutional garnet crystal material for a solid-state laser of the present invention having a composition having a refractive index slightly higher than that of YAG and having a small lattice constant difference from the YAG substrate to such an extent that the crystallinity does not decrease, is grown. It could be easily formed by processing the layer made of the material into the core 10 by photolinography and ion milling, and finally growing the upper clad 11 made of YAG by the LPE method. The substrate material itself acts as the lower clad. Further, in order to evaluate the characteristics when the substitutional garnet crystal material for a solid-state laser of Example 2-1 is used as a waveguide type laser material, both ends of the optical waveguide are cut and polished, and the Wavelength of 0.98 to 1.0 at outgoing / incident end 12
A coating with a reflectance of about 99% at 4 μm was applied.

FIG . 6 shows a measurement system for evaluating the characteristics of the substitutional garnet crystal material for solid-state laser of Example 2-1 as a laser material. An AlGaAs semiconductor laser 1 having a wavelength of 0.810 μm was used as the excitation light source. Semiconductor laser 1
The excitation light 3 emitted from the laser beam is incident on the optical fiber 7 using a lens, and is incident on the optical waveguide 8 having a core made of the substitutional garnet crystal material for the solid-state laser of Example 2-1 through the optical fiber 7. The laser oscillation characteristic was evaluated by receiving the emitted light 5 from the emitting end of the optical waveguide 8 with the optical fiber 7'and observing it with the optical spectrum analyzer 6.

[0037]

Example 2-1 This example shows the composition formula Y _3-XY Nd.
_{X Yb Y Al 5-Z Ga} Z O to produce an optical waveguide having a core of the present invention the solid-state laser for substituted garnet crystal material expressed by _12, investigate laser oscillation characteristics using a measuring system shown in FIG. 6 It was done. In this example, the refractive index of the substitutional garnet crystal material for solid-state laser is set to be slightly larger than that of the substrate material YAG, and the difference in lattice constant from YAG is within the range where the crystallinity does not decrease.
X = 0.13, Y = 0.80, Z =
Selected to 0.17. The optical waveguide having the core of the substitutional garnet crystal material for the solid-state laser of this example is 1.025.
Laser oscillation was performed at a wavelength of μm. Also, the threshold is 13 mW
It oscillates at 1 and is difficult to realize with conventional materials 1
It oscillated at a low threshold value of 00 mW or less.

Table 1

[Table 1]

Table 1 continued

[Table 2]

Table 2

[Table 3]

Table 2 continued

[Table 4]

Table 3

[Table 5]

Table 3 continued

[Table 6]

Table 4

[Table 7]

Table 4 continued

[Table 8]

[0046]

As described above, the substitutional garnet crystal material for solid-state laser of the present invention is 0.98 to 1.04 μm.
Since it oscillates at a low threshold value of 100 mW or less in the m wavelength band, it has an advantage that it can be put to practical use. Further, unlike the conventional materials, a semiconductor laser that oscillates in the 0.8 μm band that is inexpensive and has a high output can be used as the excitation light source, so that it has great economic and performance advantages.

In a specific embodiment of the present invention,
Due to experimental and time constraints, great restrictions were made on the composition of the material. However, as long as there is no significant change from these compositions and no problem occurs in crystal growth, the effect of the present invention Of course, for the materials that give rise to, they are within the scope of the invention.

Further, when crystal growth is performed, it is unavoidable that some unintended elements such as platinum, which is a crucible material, are positively mixed, so that these mixed elements do not essentially affect the effect of the present invention. As far as possible, materials containing these mixed elements are also included in the scope of the present invention.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a measurement system for evaluating characteristics of a substitutional garnet crystal material for a solid-state laser of Example 1 (Examples 1-1 to 1-9 ) as a laser material.

FIG. 2 is a composition formula Y _3-X-Y Nd _X Yb _Y Al _5-Z G.
_{a Z O 12 (X = 0.1} , Y = 1.0) shows the relationship between the lasing wavelength and threshold and Ga concentration Z of the solid-state laser for substituted garnet crystal materials of the examples represented by.

FIG. 3 is a composition formula Gd _3-XY Nd _X Yb _Y Al.
_5-Z-W Ga _Z Sc _W O ₁₂ (X = 0.13, Y =
1.2, W = 2.00) is a diagram showing the relationship between the laser oscillation wavelength, the threshold value, and the Ga concentration Z of the substitutional garnet crystal material for a solid-state laser of the example.

FIG. 4 is a composition formula Y _3-X-Y-V La _V Nd _X Yb _Y A.
l _5-Z Ga _{ZO 12} (X = 0.13, Y = 1.00,
The figure which shows the laser oscillation wavelength of the substitution type garnet crystal material for solid-state lasers of Example 1-15 represented by Z = 0.17), the threshold value, and the La concentration V.

FIG. 5 is a perspective view of an optical waveguide having a core made of a garnet crystal material for laser.

FIG. 6 is a diagram showing a measurement system for evaluating the characteristics of an optical waveguide having a core made of a substitutional garnet crystal material for a solid-state laser as a waveguide type laser.

FIG. 7 is a diagram showing an energy diagram of praseodymium.

FIG. 8 is a diagram showing a relationship between a Ga concentration Z, a laser oscillation wavelength, and an oscillation threshold value.

FIG. 9 is a diagram showing a relationship between a Ga concentration Z, a laser oscillation wavelength, and an oscillation threshold value.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Lens 3 Excitation light 4 Disk made of substitutional garnet crystal material for solid state laser 5 Emission light 6 Optical spectrum analyzer 7 Optical fiber 8 Optical waveguide 9 having a core made of substitutional garnet crystal material 9 Substrate 10 Core 11 Cladding 12 Light entrance / exit end

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Yamada 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Yasunori Oishi 1-1-6 Uchiyuki-cho, Chiyoda-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Makoto Shimizu 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Shoichi Sudo 1-1-6 Uchiyuki-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation Incorporated (56) Reference JP 5-251795 (JP, A) JP 6-37371 (JP, A) JP 6-120606 (JP, A) JP 6-209135 (JP, A) JP-A-6-326394 (JP, A) JP-A-6-350171 (JP, A) JP-A-7-183608 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) C30B 1/00-35/00 H01S 3/0 0-3/30 CA (STN)

Claims (4)

(57) [Claims] 1. A general formula is represented by R ₃ A ₅ O ₁₂ , wherein R is yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, Substitutional garnet consisting of any combination of one or more elements selected from bismuth, and A consisting of any combination of one or more elements selected from aluminum, scandium and gallium A substitutional garnet crystal material for a solid-state laser, characterized in that the crystal contains at least neodymium, ytterbium, and gallium as its constituent elements. 2. A general formula is represented by R ₃ A ₅ O ₁₂ , wherein R is yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, Substitutional garnet consisting of any combination of one or more elements selected from bismuth, and A consisting of any combination of one or more elements selected from aluminum, scandium and gallium A substitutional garnet crystal material for a solid-state laser, characterized in that the crystal contains at least neodymium and ytterbium as its constituent elements. 3. Occupancy rate of neodymium is 1% of all rare earth elements.
Or more, according to claim 1 or 2 occupancy ytterbium is equal to or less than 40% of the total rare earth elements
A substitutional garnet crystal material for a solid-state laser according to claim 1. Wherein R as lanthanum, gadolinium, either solid laser for substituted garnet crystal that any combination of one or more elements selected from among yttrium claim 1, wherein the 3, wherein material.