JP3434241B2 - Excitation method of 1.4 to 1.52 μm band optical amplifier or laser oscillator - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to 1.4 to 1.52.
The present invention relates to a method for exciting an optical amplifier or a laser oscillator used in optical communication in the μm band.

[0002]

2. Description of the Related Art In optical communication, the minimum loss wavelength of a quartz fiber is 1.55 μm band, and the zero dispersion wavelength is 1.3.
The μm band has been used. Research and development of optical amplifiers have been actively carried out for these wavelength bands, and particularly great success has been achieved in the 1.55 μm band. In recent years, there has been a demand for high-speed and large-capacity internet and data transmission, and wavelength division multiplexing (WDM) is being put to practical use from the viewpoint of increasing the communication capacity. However, with the 1.55 μm band alone, there is a possibility that the capacity will eventually become insufficient, and there is a movement to seek another band. In particular, there is a strong demand that the entire wide transmission wavelength range of the quartz fiber of 1.3 to 1.7 μm be used for communication. Therefore, the 1.47 μm band containing Tm or 1.
Research on a 65 μm band fiber amplifier is actively conducted.

[0003]

It has been proposed to use a Tm-doped low phonon glass fiber for amplification or laser oscillation in the 1.47 μm band (1988).
Minutes of the 14th European Optics Commission, DN Payne et al. Rareear
th-doping fiber laser and amplifiers pp49-53. and IEEE.J.Quantum Electronics vol.24 (6) (1988) 92
0-923 etc.). The Tm level is shown in FIG. 1.47
Amplification in the μm band is performed by utilizing the stimulated emission process of ³ H ₄ → ³ F ₄ , and actually 1.4 to 1.52 μm
Has a wide gain and amplification band. As an excitation method, a method of performing two-step excitation at 1.06 μm (Japanese Patent Laid-Open No. 5-2
No. 75792), Tm of 0.7 to 0.89 μm band
A method of directly exciting ³ H ₄ (Japanese Patent Application Laid-Open No. 4-265251) and a method of performing two-step excitation in the 1.2 μm band (Japanese Patent Application Laid-Open No. 4-26525).
No. 180279) is disclosed. But,
The fluorescence lifetime of the ³ H ₄ level of Tm is shorter than that of ³ F ₄ , and it is known that it is difficult to obtain the population inversion required for amplification or laser oscillation. Such a characteristic is called a self terminating mechanism and is not suitable for highly efficient amplification or laser oscillation. Therefore, in order to shorten the life of ³ F ₄ , Eu, Tb, H
Method of adding o, Pr, etc. (JP-A-4-265251)
JP-A-5-145168, JP-A-7-4
No. 5899). However, if these co-additive elements are added at a certain concentration or more, unfavorable energy transfer occurs due to a tail of absorption even in the 1.4 to 1.52 μm band of the target wavelength and 1.4 to 1.5
Since it adversely affects the amplification efficiency in the 1.52 μm band,
There is a limit to the composition of the amplification medium. Further, it has been proposed to pump a Tm-doped fiber at two wavelengths, but both are short-wavelength light sources utilizing an up-conversion process (for example, Japanese Patent Laid-Open Nos. 5-319858 and 8-19838).
307000 publication etc.).

Further, the ratio of branch probabilities from ³ H ₄ which is the upper level of emission in the 1.47 μm band to each of ³ H ₅ , ³ F ₄ and ³ H ₆ is 20: 50: 480 in order. Yes, there are overwhelmingly many transitions to the ground level. Therefore, ^3, a method for exciting the H ₄ directly (excitation wavelength 0.8μm so), by the excitation light of high intensity, ³ H ₄ than the stimulated emission of 1.47μm band ⁽³ H ₄ → ³ F ₄₎ → Stimulated release of ³ H ₆ is 10 times more likely to occur,
It has been virtually impossible to realize a 1.47 μm band amplifier or laser that operates with a power conversion efficiency of 10% or more with an m-containing glass waveguide or fiber.

[0005]

[Means for Solving the Problems] The inventors of the present invention have made earnest studies to solve the above-mentioned problems, and as a result, not only can an inversion distribution be efficiently formed between ³ H ₄ and ³ F ₄ , but also ³ H ₄ → ³ H ₆
The present invention has been reached by finding an excitation method capable of suppressing the emission of γ.

That is, according to the present invention, in a 1.4 to 1.52 μm band optical amplifier or laser oscillating device using an optical waveguide containing Tm in a core as an amplifying medium, at least 1.0 to 1.2 μm as a pumping light source is used. A high-efficiency 1.4 to 1.52 μm band optical amplifier or laser by exciting at two or more different wavelengths of at least one wavelength from the range and at least one wavelength from the range of 0.65 to 0.75 μm An oscillator is provided.

The present invention will be described in detail below.

High efficiency 1.4 to 1.52 with Tm added
μm band (energy difference: about 6800cm ^-1) to the optical amplification or laser oscillation, the phonon energy 700 cm ^-1
The following low phonon energy materials are suitable, and high phonon energy materials (generally about 1000 cm ⁻¹ ) such as silica-based oxides and boric acid-based oxides are considered unsuitable. Such low phonon energy glass materials include halide glass, chalcogenide glass, halide oxide glass, chalcogenide glass, tellurite glass (telluite glass), bismuthate glass,
Germanate glass and gallate glass are known. However, these low phonon energy glass materials are well known as up-conversion laser materials, and the excitation energy is consumed by red or blue light emission by a normal excitation method, and light emission in the 1.4 to 1.52 μm band It is known that the efficiency is extremely low. Also, ³
The fluorescence lifetime of H ₄ is shorter than that of ³ F ₄ in the lower emission level, which is a typical example of a self-stop mechanism, and it is known that laser oscillation itself is difficult. Very low efficiency (eg JY Allain et al., Electro
nics lett. 25 (1989) 1660-1662). Therefore, Eu, T
Attempts have been made to shorten the fluorescence lifetime of ³ F ₄ by adding b, Ho, Pr or the like. However, since these co-added elements also have a wide absorption wavelength band, if a sufficient concentration for shortening the life is added, absorption occurs in the 1.4 to 1.52 μm band or due to the upconversion process due to energy transfer. There was a problem that the luminous efficiency in the 1.4 to 1.52 μm band was lowered. As another method, it is possible to shorten the lifetime of ³ F ₄ by utilizing the oscillation of ³ F ₄ → ³ H ₆ (base), but since nearly half of the energy of the excitation light is discarded, Not preferable for efficiency. Further, as an even bigger problem, the transition probability from the emission upper level ( ³ H ₄ ) of Tm to the ground level ( ³ H ₆ ) is about 10 times as large as the transition probability to the target ³ F ₄ . To be Because of this, ³
In the excitation method of H ₆ → ³ H ₄ (wavelength 0.8 μm band), stimulated emission ( ³ H ₄ → ³ H ₆ ) by high-intensity excitation light occurs at the same time as the excitation process by absorption, and Tm ions in the ground state There was a problem that efficiency could not be reduced because the number could not be reduced.

In contrast to these methods, the present invention has a wavelength of 0.6.
Excitation at two or more different wavelengths from the range of 5 to 0.75 μm, at least one wavelength, and from the wavelength range of 1.0 to 1.2 μm, at least one wavelength, by two or more different wavelengths, thereby reversing without co-adding element. Distribution is easier to form, and ³
It was found that the emission of H ₄ → ³ H ₆ is unlikely to occur, and that amplification or laser oscillation can be performed with high efficiency and low excitation power.

The excitation method of the present invention will be described in more detail with reference to FIG.
I will explain. First, it is contained in the core of the optical waveguide
The Tm ion to be selected from the wavelength of 0.65 to 0.75 μm
Excitation light of at least one wavelength (hereinafter referred to as excitation light 1)
, The ground state (³H₆) →³F₂Or³F₃Encourage
Occurs (excitation process 1). Next, the radiationless relaxation process (radiation
After step 1)³H_FourRelaxed to³H_Four→³F_FourTransition (radiation
In the process 2), emission or amplification of 1.4 to 1.52 μm band
Occurs. Next, select from the range of wavelength 1.0 to 1.2 μm
Excitation light of at least one wavelength (hereinafter referred to as excitation light 2)
Lower emission level (³F_Four) →³F₂Or³F₃To
Excitation (excitation process 2). By this excitation ³F_FourThe presence of
The probability is effectively reduced and the self-stop mechanism can be avoided.
Finally,³F₂Or³F₃→³H_FourNon-radiative transition of (radiative process
After 1), again³H_Four→³F_Four(Radiation process 2)
Light emission in the band of 4 to 1.52 μm occurs. With this excitation method
Is, as you can see from Figure 2,³F_FourIs the virtual ground level
The four-level process used as
Is extremely easy. Also, with this method,³H_Four→³
H₆The strong light in the 0.8 μm band corresponding to the energy difference of
Because it does not exist³H_Four→³H₆Stimulated emission of
The³H_Four→³F_FourThe transition probability of can be increased.

Explaining the excitation method of the present invention from the absorption spectrum with reference to FIG. 3, ³ H ₆ → ³ F _{3 is} generated by the excitation light 1.
Or ³ H ₆ → ³ F ₂ transition, ³ F ₄ → ³ F ₂ depending on excitation light ₂
Or it can be easily understood that the transition of ³ F ₄ → ³ F ₃ occurs. Moreover, within the excitation wavelength 1, 0.68 to 0.72 μ
The m band is particularly preferred because it can simultaneously avoid the ³ H ₄ → ¹ D ₂ and ³ H ₅ → ¹ G ₄ upconversion processes. Also,
Of the excitation wavelength 2, the 1.0 to 1.1 μm band is ³ H ₄ →
^{It is} particularly preferred because it avoids the ¹ G ₄ up-conversion process.

The optimum wavelength selection of the excitation wavelength 1 and the excitation wavelength 2 cannot be unconditionally specified because it depends on the concentration of Tm added and the type of glass material, but it is set within the range of each wavelength band of the present invention. be able to. For example, Tm: ZBLA
For N (fluoride glass), excitation wavelength 1 is 0.69μ
m and 1.064 μm can be selected as the excitation wavelength 2. The optimum combination of pumping light powers depends on the Tm concentration, the material of the optical waveguide, the numerical aperture of the waveguides, etc., and therefore cannot be specified unconditionally, but it is expressed by the power of the pumping wavelength 1: the power of the pumping wavelength 2. Excitation power ratio is 95: 5 to 5: 9
It is preferably in the range of 5. When the excitation wavelength 2 (wavelength 1.0 to 1.2 μm) is weaker than this range, ³ H ₄
^It becomes difficult to form a population inversion between ³ F ₄ and sufficient amplification efficiency cannot be obtained. Excitation wavelength 1 (wavelength 0.
65 to 0.75 μm) is weak, the ground level ( ³ H ₆ )
→ Because ³ F ₂ or ³ F ₃ is not excited effectively, the ratio of ions that can be used for amplification is reduced and gain cannot be obtained. Further, the above-mentioned pump power ratio is 80:20 to 20: 8.
In the range of 0, population inversion can be formed even with low pumping power, which is particularly preferable.

When the excitation method of the present invention is used, it is clear that any material capable of amplifying the 1.47 μm band in the Tm-added medium can be used. As such a material, a glass having a low phonon energy is generally used, and a chalcogenide glass, a halide glass, a chalcogenide glass, a halide oxide glass, a tellurite glass (tellurite glass), a bismuthate salt. Glass, germanate glass, and gallium salt glass are preferable, and it is particularly preferable to use the core portion.

As the excitation laser, a semiconductor laser,
Any laser that oscillates in the excitation wavelength band of the present invention, such as a dye laser, a solid-state laser, or a gas laser, may be used.
Particularly, a semiconductor laser with a fiber pigtail, a solid-state laser combined with a fiber, and a fiber laser are preferable. In terms of price and size, a semiconductor laser is used for the excitation wavelength 1 (wavelength 0.65 to 0.75 μm), and a solid-state laser added with Nd or Yb for the excitation wavelength 2 (wavelength 1.0 to 1.2 μm). Fiber lasers are preferred. Further, in order to fully utilize the absorption band of Tm to enhance the excitation efficiency, a laser having a wide oscillation wavelength band (for example, Raman laser) is used, or a plurality of lasers having different wavelengths in each excitation wavelength band are combined. Is also effective.

When constructing an optical amplifier, an optical element for optical communication such as a wavelength division multiplexing element (WDM) or an optical isolator can be used if necessary. Further, it is preferable that the amplifier has a gain monitoring function or a gain equalizing function built-in or attached thereto because the reliability of the optical communication system is improved.
For monitoring the gain, any method may be used as long as it can substantially compare the incident signal light intensity and the output signal light intensity. When performing wavelength division multiplexing, it is desirable to use a method capable of detecting and monitoring each signal assigned to each wavelength. The gain equalization function may be a passive method or an active method. As a passive gain equalization method, a configuration using an optical filter is simple. The active gain equalization method is composed of a gain monitoring function and a feedback function, and any method can be used as long as it can substantially compare the incident signal light intensity and the output signal light intensity and make the gain constant. . When performing wavelength division multiplexing communication, it is desirable to use a method capable of gain equalization for each signal assigned to each wavelength. Although it has the same function as the gain equalization, the output equalization function that keeps the output signal light intensity constant is as effective as the gain equalization function. These functions are preferably automatically adjustable, such as by a remotely programmable microprocessor.

In the case of constructing a laser oscillator, the output can be increased by connecting the optical waveguides in a ring shape or connecting a plurality of optical waveguides in series or in parallel. Also, narrow band oscillation using a fiber grating, variable wavelength oscillation, and ultrashort pulse oscillation by pulse compression are possible.

As described above, the excitation wavelength is 0.65
By using dual wavelength excitation of 0.75 μm band and wavelength of 1.0 to 1.2 μm, the efficiency of 1.4 is higher than that of normal single wavelength excitation.
It is possible to provide an optical amplifier or laser oscillator in the band of ~ 1.52 μm.

[0018]

The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.

Example 1 Fluoride glass fiber having 0.1% by mol of Tm added to the core was used. The basic glass composition of the core and clad is shown below. Tm replaces La. The numbers are
It is mol%.

Core composition: 51ZrF ₄ -19BaF _2-
4.5LaF ₃ -2YF ₃ -2AlF ₃ -13.5LiF
-8PbF ₂ Cladding composition: 40HfF ₄ -10ZrF ₄ -19BaF
₂ -3LaF ₃ -2YF ₃ -4AlF ₃ -22NaF relative refractive index difference of the fiber is 1.1%, the cutoff wavelength is 0.65 .mu.m, the core diameter was 2.2 .mu.m.
The fiber length is 3 m.

Next, the configuration of the optical amplifier used for the measurement is shown in FIG.
Shown in. For excitation, a semiconductor laser 2 having a wavelength of 0.69 μm and an Nd: YAG laser 3 having a wavelength of 1.064 μm are multiplexed, and a fluoride fiber for optical amplification is passed through an optical multiplexing / demultiplexing element 4 and a quartz fiber 5 having a high NA. Combined with 1.
The quartz fiber 5 and the fluoride fiber 1 were bonded by using a V-groove block, and the joint end surface was obliquely optically polished to reduce reflection loss, and fixed with an ultraviolet-curing optical adhesive. The signal light from the signal generator 6 in the 1.47 μm band is incident on the amplification fiber via the optical multiplexing / demultiplexing element 4, and the amplified output light is passed through the optical isolator 7 and the measuring instrument 8
The small signal gain was measured at. The input signal light is continuous light having a wavelength of 1.47 μm and an intensity of −30 dBm. FIG. 5 shows the small signal gain when pumping at a single wavelength of 0.69 μm or 1.064 μm and the small signal gain when pumping at two wavelengths at the same time. The input power in the case of dual wavelength pumping is the total power of the dual wavelengths, and the power ratio is fixed at 4: 6. It can be seen that in dual-wavelength pumping, the gain is improved by 5 dB or more as compared with single-wavelength pumping, and the threshold value is low.

Example 2 An experiment was conducted by using the same fluoride fiber as in Example 1 and changing the pumping power ratio with the same structure. The incident condition of the signal light and the excitation wavelength were the same as in Example 1, and the total power of the two wavelengths was fixed at 100 mW for measurement. Results are shown in FIG. Excitation wavelength 0.69 μm and 1.064 μm power ratio in the range of 95: 5 to 5:95 wavelength 0.69 μm
Alternatively, it can be seen that the gain is higher than that in the case of single wavelength pumping at a wavelength of 1.064 μm. Especially, the power ratio is 80: 2
In the range of 0 to 20:80, the gain was higher by 2 dB or more than the gain in the case of single wavelength excitation.

Example 3 With the same configuration as that of Example 1, the amplification medium was an In-based fluoride glass fiber, and the small signal gain was measured. The addition concentration of Tm was 0.2 mol%, and part of Gd was replaced. Numbers are mol%.

Core composition: 18InF ₃ -12GaF ₃ -2
0ZnF ₂ -27BaF ₂ -3PbF ₂ -10GdF ₃ -1
0YF ₃ clad composition: 18InF ₃ -12GaF ₃ -20ZnF
₂ -18BaF ₂ -12SrF ₂ -10GdF ₃ -10YF
₃ The relative refractive index difference of this fiber was 1.1%, and the cutoff wavelength was 0.65 μm. The fiber length used for the measurement is 2 m. For excitation, a semiconductor laser having a wavelength of 0.695 μm and a Yb: YAG laser having a wavelength of 1.02 μm were used. As in Example 1, the single-wavelength pumping and dual-wavelength pumping (power ratio 4: 6) were measured, and as a result, as shown in FIG. 7, the dual-wavelength pumping had a higher gain of 5 dB or more.

Example 4 With the same structure as in Example 1, a small signal gain was measured using a tellurite-based oxide glass fiber as the amplification medium. Tm
The addition concentration of is 0.1 mol%, and a part of La is replaced. Numbers are mol%.

Core composition: 90TeO ₂ -8BaO -2L
a ₂ O ₃ cladding _{composition: 81TeO 2 - 16BaO -3Y 2 O} 3 relative refractive index difference of the fiber, 0.7%, cut-off wavelength was 0.65 .mu.m. The fiber length used for the measurement is 1.5 m. For excitation, a semiconductor laser having a wavelength of 0.695 μm and an Nd: YVO ₄ laser having a wavelength of 1.064 μm were used. As shown in FIG. 8, the gain in dual wavelength excitation was 3 dB or more higher than that in single wavelength excitation.

Example 5 With the same construction as in Example 1, a small signal gain was measured using a bismuth oxide glass fiber as the amplification medium. The concentration of Tm added was 0.1 mol%, which partially replaced La. Numbers are mol%.

Core composition: 75Bi ₂ O ₃ -18B ₂ O ₃ -5
SiO ₂ -2La ₂ O ₃ clad composition: 70Bi ₂ O ₃ -15CdO-15B ₂ O _{3 The} fiber had a relative refractive index difference of 1.2% and a cutoff wavelength of 0.65 μm. The fiber length used for the measurement is 2 m. For excitation, a semiconductor laser having a wavelength of 0.695 μm and an Nd: YLF laser having a wavelength of 1.057 μm were used. As in the case of Example 1, the single wavelength pumping and the dual wavelength pumping (power ratio 1: 1) were measured, and as a result, as shown in FIG. 9, the dual wavelength pumping had a higher gain of 3 dB or more.

Example 6 With the same construction as in Example 1, a gallate glass fiber was used as an amplification medium, and a small signal gain was measured. The addition concentration of Tm is 0.3 mol%. Numbers are mol%.

Core composition: 30K ₂ O-30Ta ₂ O ₃ -4
0Ga ₂ O ₃ clad composition: 30K ₂ O-25Ta ₂ O ₃ -45Ga ₂ O
₃ The relative refractive index difference of this fiber was 1.2%, and the cutoff wavelength was 0.65 μm. The fiber length used for the measurement is 0.7 m. The excitation is a semiconductor laser with a wavelength of 0.695 μm and Nd: YAG with a wavelength of 1.064 μm.
A laser was used. As in Example 1, the results of single wavelength excitation and dual wavelength excitation (power ratio 1: 1) were measured.
As shown in FIG. 10, the dual-wavelength pump had a higher gain of 3 dB or more.

Example 7 With the same configuration as in Example 1, a sulfide glass fiber was used as an amplification medium, and a small signal gain was measured. The addition concentration of Tm is 0.1 mol%. Tm replaces La. Numbers are mol%.

Core composition: 30In₂S₃-40 Ga₂S₃−
30 La₂S₃ Cladding composition: 12Al (PO₃)₃-11AlF₃-3
0.5 RF₂ -46.5MF₂ (R: Mg, Ca M: S
r, Ba) The relative refractive index difference of this waveguide is 1.2%, the cutoff wavelength
Was 0.65 μm. Fiber used for measurement
Is 1.5 m long. Single wavelength excitation as in Example 1
And the two wavelength excitation (power ratio 1: 1) was measured.
As a result, as shown in FIG. 11, dual wavelength excitation is 3 dB or more.
It was a high gain.

[0033]

By using the excitation method of the present invention,
High efficiency 1.4 to 1.52 μm band optical amplifier or 1.4
A ~ 1.52 μm band laser oscillator can be constructed.

[Brief description of drawings]

FIG. 1 is a level diagram and an absorption spectrum of Tm.

FIG. 2 is a diagram illustrating a level of Tm and an excitation method of the present invention.

FIG. 3 is a diagram showing an absorption cross section from each level of Tm.

FIG. 4 is a configuration diagram of an amplifier according to the first exemplary embodiment.

FIG. 5 is a diagram showing the pump power dependence of the amplification factor in the first embodiment.

FIG. 6 is a diagram showing the power ratio dependency of the amplification factor of the excitation wavelength 1 and the excitation wavelength 2 in the second embodiment.

FIG. 7 is a diagram showing pump power dependence of amplification factor in Example 3;

FIG. 8 is a diagram showing the dependence of the amplification factor on the excitation power in Example 4;

FIG. 9 is a diagram showing the dependence of the amplification factor on the excitation power in Example 5.

FIG. 10 is a diagram showing the pump power dependence of the amplification factor in Example 6;

FIG. 11 is a diagram showing pump power dependence of amplification factor in Example 7.

[Explanation of symbols]

1 Optical amplification fiber 2 Semiconductor laser that supplies 1 excitation wavelength 3 Nd: YAG laser that supplies excitation wavelength 2 4 Optical multiplexer / demultiplexer 5 High NA quartz fiber 6 Signal light generator with wavelength 1.47 μm 7 Optical isolator 8 measuring instruments

─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Kiyotaka Miura 5253 Oki Ube, Ube City, Yamaguchi Prefecture Central Glass Co., Ltd. Chemical Research Laboratory (72) Inventor Takuya Tejima 5253 Oki Ube, Ube City Yamaguchi Prefecture Central Glass Chemical Research Institute Co., Ltd. (56) Reference JP 5-275792 (JP, A) JP 5-145168 (JP, A) JP 3-289186 (JP, A) JP 2000-353837 (JP , A) JP 2000-307176 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01S 3/00-3/30 C03C 4/12

Claims (7)

(57) [Claims] 1. In a 1.4 to 1.52 μm band optical amplifier provided with at least a pumping light source, a multiplexer / demultiplexer, and an amplification optical waveguide, a core portion of the amplification optical waveguide contains Tm and has a wavelength of 1. 1. Excitation at two or more kinds of wavelengths different from each other, that is, at least one wavelength in the range of 0 to 1.2 μm and at least one wavelength in the range of 0.65 to 0.75 μm. A method for exciting a 52 μm band optical amplifier. 2. A 1.4 to 1.52 μm band laser oscillator equipped with at least a pumping light source, a multiplexer / demultiplexer, and an amplification optical waveguide, wherein the core portion of the amplification optical waveguide contains Tm,
It excites at two or more kinds of wavelengths different from each other, that is, at least one wavelength in the range of wavelength 1.0 to 1.2 μm and at least one wavelength in the range of wavelength 0.65 to 0.75 μm. ~ 1.52 µm band laser oscillator excitation method. 3. The core portion of the amplification optical waveguide comprises a halide oxide glass, a halide glass, a chalcogenide glass,
3. At least one type of glass selected from chalcohalide glass, tellurite glass, bismuthate glass, germanate glass, and gallium salt glass. 1.
A method for exciting a 52 μm band optical amplifier or laser oscillator. 4. The pumping method for a 1.4 to 1.52 μm band optical amplifier or laser oscillator according to claim 1, wherein at least one of the pumping light sources is a semiconductor laser. 5. At least one of the pumping light sources is a semiconductor laser pumped solid-state laser.
4. The pumping method for a 1.4 to 1.52 μm band optical amplifier or laser oscillator according to claim 3. 6. The 1.4 to 1.52 μm band according to claim 5, wherein the solid-state laser is a laser using a crystal doped with Nd or Yb, or a glass fiber doped with Nd or Yb. Excitation method of optical amplifier or laser oscillator. 7. A pumping power having a pumping wavelength selected from the range of 0.65 to 0.75 μm and a wavelength of 1.0 to 1.2.
The ratio of the pumping power of the pumping wavelength selected from the range of μm is
It is in the range of 95: 5 to 5:95, 1.4 to 1.52μ according to any one of claims 1 to 6.
A method for exciting an m-band optical amplifier or a laser oscillator.