JP2000272933A - Tellurite glass for optical amplification, and optical fiber, light amplifier and laser system all using the same glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare glass useful as a fiber host capable of making a gain spectrum of a tellurite optical fiber amplifier be more flattened and be extended on the side of a longer wavelength by including a specific amount of P2O5 in tellurite glass. SOLUTION: This glass comprises >10 mol% P2O5, which leads to capability of sufficiently reducing the peak of 1.56 μm zone in a spectrum. The glass has a composition of the formula TeO2-ZnO-M2O-L2O3-P2O5 (wherein, M is an alkali element; L is Bi, La, Al, Ce, Ye or Lu). By employing a core made of the glass in an added state with erbium as an optical fiber or a host glass for an optical waveguide, the cross section of stimulated emission at 1.56 μm and 1.6 μm zones can be changed, a deviation between gains at 1.56 μm and 1.6 μm zones is reduced and a gain threshold wavelength of 1.6 μm zones on the side of a longer wavelength can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to tellurite glass for optical amplification, an optical fiber and an optical amplification medium using the glass, and the optical amplification medium is further applicable to a broadband optical amplifier and a laser device. is there.

[0002]

2. Description of the Related Art At present, optical signals of a plurality of wavelengths are multiplexed and transmitted in one optical fiber or conversely, in order to expand the transmission capacity and improve the function of an optical communication system. Wavelength multiplexing transmission technology (WDM: Wavelength D) for demultiplexing optical signals of a plurality of wavelengths propagated in an optical fiber for each wavelength.
ivision Mutiplexing) is being researched and developed.

In this transmission system, optical signals of a plurality of different wavelengths are transmitted by one optical fiber. If the transmission distance is long, the signals are amplified and relayed in the middle as in the conventional case. There is a need. For that purpose, that is, in order to increase the optical signal wavelength and increase the transmission capacity, an optical amplifier having a wide amplification wavelength band is required.

The wavelength of a system for maintaining and monitoring an optical communication system ranges from 1.61 μm to 1.66 μm.
It is considered that a wavelength between m and m is preferable, and development of a light source and an optical amplifier for a maintenance / monitoring system corresponding to such a wavelength is desired.

In recent years, for the purpose of application to the optical communication field,
Research and development of an optical fiber amplifier using an optical fiber in which a core is doped with a rare earth element as an optical amplification medium, for example, an Er (erbium) -doped optical fiber amplifier (EDFA) has been promoted, and application to an optical communication system has been actively promoted. ing.
This EDFA operates in the 1.5 μm band where the loss of the silica-based optical fiber is minimized, has a high gain of 30 dB or more, low noise, a wide gain band, is independent of the polarization, and has a high saturation output. , Etc.

One of the performances required when applying the EDFA to the WDM transmission is that the amplification band is wide as described above. As an EDFA having a wide amplification band, a fluoride EDFA using fluoride glass as a host of an Er-doped optical fiber amplifier has been developed.

There is a tellurite EDFA in which tellurite glass is used in place of silica or fluoride glass. However, when this optical amplifier is used, the conventional quartz EDFA or fluoride EDFA of 1.53 μm to 1.56 μm is used. 1.53 μm, which is at least twice as wide as the wavelength band up to 1.
Batch amplification in a wavelength band of up to 61 μm becomes possible (A. Mori et al., OFC'97, PD1). further,
In this tellurite EDFA, the limit of gain at the long wavelength side is limited by quartz EDFA and fluoride EDFA.
Since it is wider by 7 to 9 nm than in the prior art, it is possible to realize an amplifier at a wavelength in the 1.6 μm band, which has not been conventionally available (A. Mori et al., ECOC'97, vol. 3, pp. 135-13).
8). Therefore, such tellurium and EDFA are receiving attention as EDFAs for future ultra-large capacity WDM systems.

Incidentally, the performance required as an EDFA for a WDM system is (1) wide band of amplification and (2)
The flatness of amplification. The tellurite EDFA is excellent in broadband characteristics of amplification, but is inferior in flatness of amplification. For example, gain peak wavelengths of 1.56 μm and 1.6
The gain deviation at 0 μm is 18 dB or more (A. Mo.
ri et al., supra). Therefore, tellurite EDFA is replaced by WD
In order to use the EDFA as an M system EDFA, the gain must be flattened. For this purpose, a gain equalizer such as a fiber Bragg grating must be applied to the EDFA.

However, if the gain deviation is too large,
It becomes difficult to design a gain equalizer for flattening,
Further, gain equalization cannot be performed unless a plurality of gain equalizers are used. This is the current situation. In fact, in the case of tellurite EDFA, since the gain deviation is 18 dB or more,
A gain deviation equal to or less than 1 dB applied to a WDM system has not been realized even by using a gain equalizer (M. Yamada et al., OFC'98, PD7).

Further, when a large gain deviation is flattened by using a gain equalizer, a large energy loss occurs. Therefore, the 18d required for a WDM transmission broadband optical amplifier is required.
In order to obtain a large output of Bm or more, a very high excitation light intensity is required.

Furthermore, in order to change the original shape of the amplified spectrum of the EDFA, it is necessary to change the shape of the stimulated emission cross section spectrum.

[0012] In the case of tellurite EDFA, 1.5% is required to make the gain spectrum flat and easy to equalize the gain.
It is preferable to use a fiber host in which the stimulated emission cross-sectional area at the peak portion of the gain near the 6 μm band is reduced.
This is because in this case, the gain deviation between the wavelength band from 1.53 μm to 1.56 μm and the 1.6 μm band can be reduced.

Further, in order to extend the long wavelength limit of the gain, the value of the stimulated emission cross section in the 1.6 μm band and the value of Exci
It is preferable to use a fiber host that shifts the wavelength at which the value of the cross-sectional area of ted state absorption (excitation level absorption: ESA) coincides with the longer wavelength side. This is because that wavelength is the long wavelength limit of the original gain.

As a conventional fiber host of tellurite EDFA, TeO ₂ —ZnO—Na ₂ O—Bi ₂ O ₃
And _{TeO 2 -ZnO-Li 2 O-} Bi 2 O 3 ( Japanese Patent Application No. 1
No. 0-31874). In these glass systems, the gain deviation is more than 18 dB,
The long wavelength limit of the gain is 1637 nm.

[0015]

However, the composition of these glasses is not known so that when these glasses are applied as a fiber host, the gain spectrum of tellurite EDFA becomes flatter.

An object of the present invention is to provide a tellurite glass for optical amplification, which has a flatter gain spectrum of a tellurite EDFA and can be used as a fiber host capable of extending a band to a longer wavelength side. Broadband tellurite EDF with gain flattening as amplification medium
A and a laser device.

[0017]

The most important feature of the present invention resides in the addition of P ₂ O ₅ to tellurite glass.

When P ₂ O ₅ is added to quartz glass,
The stimulated emission cross section of Er added to the silica-based glass shows a characteristic spectrum (for example, PF Wysocki, O.
AA'96, SaA2-1) There is almost no intensity in the 1.6 μm band, and it is difficult to realize broadband amplification.

However, this is the effect of adding P ₂ O _{5 to} the silica-based fiber, and the effect of the tellurite-based fiber on the gain spectrum was not clear.

The above-mentioned patent application (Japanese Patent Application No. 10-318)
No. 74), "PO vibration energy is 120
As large as 0 cm ^-1, by the addition of the phosphorus is a method of exciting a ⁴ I _11/2 level of Er by light near a wavelength of 0.98 .mu.m, even in this method, ⁴ I _13/2 level Of the present invention does not reduce the pumping effect and has the advantage of excellent noise characteristics. " However, there is no description in this application specification regarding the gain spectrum,
Also in the embodiment, the addition amount of P ₂ O ₅ is as small as about 5 wt%.

The present inventors have proposed that P ₂ O is added to tellurite glass.
₅ and using this glass as a host glass of an optical fiber or an optical waveguide in which at least erbium is added to the core, the 1.56 μm band and the 1.6 are used.
The stimulated emission cross section in the μm band can be changed. As a result, the gain deviation between the 1.56 μm band and the 1.6 μm band is reduced, and the gain limit wavelength on the long wavelength side of the 1.6 μm band is extended. I found what I could do. The present inventors have completed the present invention based on such findings.

The addition amount of P ₂ O ₅ in the tellurite glass for optical amplification of the present invention is in a range exceeding 10 mol%, and when the addition amount is 10 mol% or less, the peak of the 1.56 μm band spectrum is sufficiently reduced. I can't let it.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The tellurite glass for optical amplification according to the present invention contains 10 mol of P ₂ O ₅ in tellurite glass.
It is contained in a range exceeding 1% (claim 1).

Further, another tellurite glass for optical amplification according to the present invention is TeO ₂ -ZnO-M ₂ O-L ₂ O _3-.
Has a composition consisting of P ₂ O _5, in this composition, beyond 10 mol% amount of added P ₂ O _5, M is one or more alkali elements, L is Bi, La, Al, Ce, Yb, and Lu It is characterized by being at least one or more elements selected from among them (claim 2).

The optical fiber according to the present invention is an optical fiber made of a material glass having at least a core doped with erbium, wherein the material glass is made of P ₂ O ₅ .
It is characterized in that it is contained in a range exceeding 0 mol% (claim 3).

Further, another optical fiber according to the present invention comprises:
An optical fiber made of material glass, the material _{glass, TeO 2 -ZnO-M 2 O} -L 2 O 3 -P 2 O 5
Wherein the amount of P ₂ O ₅ added exceeds 10 mol%, and M is at least one alkali element;
L is at least one element selected from Bi, La, Al, Ce, Yb, and Lu (claim 4).

An optical amplifier according to the present invention inputs an optical amplification medium comprising an optical fiber or an optical waveguide having a core glass and a clad glass, and excitation light and signal light for exciting the optical amplification medium to the optical amplification medium. An optical amplifier comprising an input means, wherein at least one of the core glass and the clad glass is made of the tellurite glass for optical amplification according to claim 1 or 2 (claims 5 and 6). .

Another optical amplifier according to the present invention is an optical amplifier comprising: an optical amplification medium; and input means for inputting excitation light and signal light for exciting the optical amplification medium to the optical amplification medium. An amplification medium is made of the optical fiber according to claim 3 (claim 7).

Still another optical amplifier according to the present invention is an optical amplifier in which a plurality of optical amplifying media each composed of an optical fiber in which at least a core of a glass core and a clad is doped with erbium are arranged in series, At least one of the core glass and the clad glass is made of the tellurite glass for optical amplification according to claim 1 or 2 (claims 8 and 9).

Further, a laser device according to the present invention is a laser device having an optical resonator having a plurality of optical amplifying media and an excitation light source, wherein at least one of the plurality of optical amplifying media has a core glass. An optical fiber or an optical waveguide having a clad glass, and at least one of the core glass and the clad glass is made of the tellurite glass for optical amplification according to claim 1 or 2 (claims 10 and 11). ).

Another laser device according to the present invention is:
A laser device in which a plurality of optical amplifying media each comprising an optical fiber in which erbium is added to at least a core of a glass core and a clad are arranged in series, and at least one of the core glass and the clad glass is according to claim 1 or 2. The invention is characterized by being made of tellurite glass for optical amplification (claims 12 and 13).

Still another laser device according to the present invention is:
A laser device having an optical amplification medium and an excitation light source,
The optical amplification medium comprising an optical fiber or an optical waveguide having a core glass and a cladding glass, wherein at least one of the core glass and the cladding glass is the tellurite for optical amplification according to claim 1 or 2. It is made of glass (claims 14 and 15).

[0033]

The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 FIG. 1 shows (74) TeO ₂ −
(16) A 1.5 μm band emission spectrum (solid line) in ZnO- (6) Na ₂ O- (4) Bi ₂ O ₃ glass and (7)
_{4-X) TeO 2 - (} 16) ZnO- (6) Na 2 O-
(4) A 1.5 μm band emission spectrum (broken line) of Er in Bi ₂ O ₃ — (X) P ₂ O ₅ glass is shown.

In the above composition, the numbers in parentheses indicate mol% of each composition, and X = 10, 15, 20 mol%. These meanings are the same in the following examples.

As is clear from the figure, in the spectrum in which the concentration of P ₂ O ₅ is 10 mol% (dashed line), 1.5%
While the peak intensity at 6 μm hardly changes as compared with the case where no additive is added, 15, 20 mol%
The intensity of the added spectrum (dotted line and two-dot chain line) decreases as the added amount increases.

The Er-doped tellurite optical fiber glass the P ₂ O ₅ was added 20 mol% as a core composition (cut-off wavelength: 1.3 .mu.m, Er concentration: 1000 ppm,
(6 m in length) and excited at 1.48 μm (200 m)
W), the gain deviation between 1.56 μm and 1.6 μm could be reduced to 15 dB or less.

When an EDFA was constructed using this optical fiber as an amplification medium and a fiber black grating as a gain equalizer, the EDFA was changed from 1.53 μm to 1.6 μm.
An EDFA with a gain deviation of 1 dB or less over 0 μm was realized.

On the other hand, P ₂ shown by a solid line in FIG.
In the case of using an optical fiber made of tellurite glass not containing O ₅ , the gain deviation between 1.53 μm and 1.60 μm is 18 dB or more, and even if the gain is corrected using a gain equalizer, the gain is not changed. Deviation is 1d over 70 nm band
It was difficult to make it B or less.

As described above, the use of the glass containing P ₂ O ₅ of the present invention for a fiber host has made it possible to reduce the gain deviation for the first time.

The effect of the addition of P ₂ O _{5 on} the gain is as follows.
TeO ₂ -ZnO- described in Japanese Patent Application No. 10-31874.
Na ₂ O—Bi ₂ O ₃ composition (55 ≦ TeO ₂ ≦ 90,
0 ≦ ZnO ≦ 35, 0 ≦ Na ₂ O ≦ 35, 0 <Bi ₂ O
₃ ≦ 20, unit mol%).

Example 2 The effect of adding P ₂ O _{5 on} the gain characteristics was confirmed for a TeO ₂ —ZnO—Li ₂ O—Bi ₂ O ₃ system glass. That is, (70) TeO ₂
- (10) ZnO- (15) Li 2 O- (5) Bi 2 O
₃ 1.5 μm band emission spectrum of Er in the glass,
_{(71-X) TeO 2 -} (11) ZnO- (13) Li
_{O 2 - (5) Bi 2} O 3 - (X) P 2 O 5 E in the glass
Comparison with the 1.5 μm band emission spectrum of r
As in the case of Example 1, in the spectrum in which the concentration of P ₂ O ₅ added was 10 mol%, the peak intensity at 1.56 μm was hardly changed as compared with the case where no P ₂ O ₅ was added. In the case of adding 20 mol%, the strength decreased as the added amount increased.

An Er-doped tellurite optical fiber (cut-off wavelength: 1.3 μm, Er concentration: 1000 pp) was used as a core composition of the glass containing 20 mol% of P ₂ O _5.
m, length 6 m) and excited at 1.48 μm (200
mW), the gain deviation between 1.56 μm and 1.6 μm could be reduced to 15 dB or less.

Using this fiber as an amplification medium and a Mach-Zehnder type filter (loss medium) as a gain equalizer,
When the EDFA was constructed, it was found that 1.53 μm to 1.60
An EDFA having a gain deviation of 1 dB or less over μm was realized. In the case where an optical fiber containing no P ₂ O ₅ is used, the gain deviation from 1.53 μm to 1.60 μm is 18 dB or more, and even if the gain is corrected using a gain equalizer, the gain deviation is 1 dB over a 70 nm band. It was difficult to:

The effect of adding P ₂ O _{5 on} the gain is as follows:
TeO ₂ -ZnO- described in Japanese Patent Application No. 10-31874.
Li ₂ O—Bi ₂ O ₃ composition (55 ≦ TeO ₂ ≦ 90,
0 ≦ ZnO ≦ 25, 0 ≦ Li ₂ O ≦ 25, 0 <Bi ₂ O
₃ ≦ 20, unit mol%), that is, a composition that can stably form a fiber.

In the above embodiment, the concentration of P ₂ O ₅ is set to 1
The content was set to 5 and 20 mol%, but the present invention is not limited to this. When the concentration of P ₂ O ₅ was in a region exceeding 10 mol%, the effect of adding P ₂ O ₅ could be confirmed.

(Example 3) However, P ₂ O ₅
Increasing the concentration of addition increases the viscosity of the glass,
Because it becomes difficult to make uniform glass without striae,
The above compositional conditions for stably forming a fiber are ignored, which is not preferable.

In this embodiment, TeO ₂ -ZnO-M ₂ O
The effect of adding P ₂ O _{5 to} the gain characteristics of -Bi ₂ O ₃ (M is an alkali element other than Li and Na) glass was confirmed. That is, when M is K, Cs, or Rb, the first embodiment
Similar to ~ 2 by addition of P ₂ O _5, 1.53
The gain deviation between .mu.m and 1.60 .mu.m can be reduced to 15 dB or less, and an EDFA is constructed using a gain equalizer. The EDFA having a gain deviation of 1 dB or less over a 70 nm band from 1.53 .mu.m to 1.60 .mu.m. Was realized.

(Embodiment 4) In this embodiment, TeO ₂ -Z
The effect of adding P ₂ O _{5 to} the gain characteristics of nO—M ₂ O—Bi ₂ O ₃ (M is an alkali element containing at least two kinds) glass was confirmed. That is, even when two or more kinds of alkali elements are contained as M, as in Examples 1 and ₂ , P ₂
By adding O ₅ , 1.53 μm and 1.60 μm
m can be reduced to 15 dB or less, and an EDFA is configured by using a gain equalizer, and 1.53 μm
An EDFA with a gain deviation of 1 dB or less was realized over a band of 70 nm from m to 1.60 μm.

(Embodiment 5) In the above embodiment, TeO ₂
The effect of adding P ₂ O _{5 to} the gain characteristics of —ZnO—R ₂ O—Bi ₂ O ₃ (R is an alkali element) glass has been described. However, the effect of adding P ₂ O ₅ is not only effective for these glass systems, but also for other tellurite systems (for example, TeO ₂ -WO ₃ system glasses) and has a wide band and flat gain. It was confirmed that it was effective for realizing EDFA.

(Example 6) (74) TeO _2- (16)
_{ZnO- (6) Na 2 O- (} 4) Bi 2 O 3 glass, and _{(59) TeO 2 - (16} ) ZnO- (6) Na 2
_{O- (4) Bi 2 O 3} - (15) the P ₂ O ₅ glass as the core composition, Er-doped tellurite optical fiber prepared (cut-off wavelength:: 1.3 .mu.m, Er concentration 1000 ppm, length 18m), and exited state absorption cross se
ction (excitation state absorption cross section: ESA cross section) was measured. FIG. 2 shows the ES at a wavelength of 1.60 to 1.67 μm.
The A cross section and the light emission cross section are shown. The wavelength at which the ESE cross section and the light emission cross section intersect is the limit on the long wavelength side where the EDFA can obtain a gain. According to this figure, the limit wavelength is
By adding 15 mol% of P ₂ O ₅ , 1637
from 16 nm to 1645 nm.

An EDFA was constructed using an optical fiber doped with 15 mol% of P ₂ O ₅ as an amplification medium and a fiber Bragg grating as a gain equalizer.
Gain deviation is 1d from 1.56μm to 1.63μm
An EDFA of B or less was realized. When an optical fiber containing no P ₂ O ₅ is used, 1.62 μm
1.6, since the gain sharply decreases around
Broadband gain flattened ED with gain on long wavelength side of 2μm or more
It was difficult to realize FA.

As described above, the use of the P ₂ O ₅ -containing glass of the present invention for a fiber host makes it possible for the first time to broaden the gain and flatness of the gain in an optical amplification medium.

The effect of adding P ₂ O _{5 to} the gain is as follows:
TeO ₂ -ZnO- described in Japanese Patent Application No. 10-31874.
Na ₂ O—Bi ₂ O ₃ composition (55 ≦ TeO ₂ ≦ 90,
0 ≦ ZnO ≦ 35, 0 ≦ Na ₂ O ≦ 35, 0 <Bi ₂ O
₃ ≦ 20, unit mol%).

Further, the TeO ₂ described in Examples 2 to 5 was used.
The same effect of adding P ₂ O _{5 to} the gain characteristics of —ZnO—R ₂ O—Bi ₂ O ₃ (R is an alkali element) glass was also confirmed. However, the effect of adding P ₂ O ₅ is not only effective for these glass systems, but also for other tellurite systems (for example, TeO ₂ -WO ₃ glass), the gain is extended to the longer wavelength side. Broadband and Flat Gain EDF
A was confirmed to be effective in achieving A.

By applying the tellurite glass for optical amplification described in the above embodiments to an optical amplifying medium, an optical amplifier and a laser device using the optical amplifying medium, the cost of various wavelength multiplexing optical transmission systems can be reduced. And high performance of optical measurement.

An embodiment of the laser device according to the present invention will be described below.

(Embodiment 7) FIG. 3 is a schematic configuration diagram of an embodiment of a laser device according to the present invention. In this example,
The amplification optical fibers 2 and 4 containing 20 mol% of P ₂ O ₅ used in Example 1 were connected in series via a wavelength-tunable band-pass filter 3 (bandwidth 2 nm).
99% transmittance at 0 nm, 1500 nm to 1650 n
A mirror 5 having a reflectance of 100% at m and a mirror 1 having a transmittance of 20% at a wavelength from 1500 nm to 1650 nm were provided at multiple ends, and laser oscillation was performed.

As a result, the signal wavelength from 1505 nm to 16
Laser oscillation can be confirmed in a wide range of 42 nm, and its output is stable within almost 10%.
It turned out that it can be used as a broadband tunable laser that can be used in the 6 μm band.

In the seventh embodiment, a laser device comprising the tellurite optical fiber shown in the first embodiment as a component has been described. However, another P ₂ O ₅ -doped tellurite optical fiber described in the claims is described. It is obvious that the same effect can be obtained in a laser device having the above as a component.

[0061]

As described above, by adding P ₂ O ₅ to conventional tellurite optical fiber glass, E
r can reduce the intensity of the 1.5 μm band emission spectrum around 1.56 μm, and as a result, tellurite EDF
It is possible to reduce the gain deviation between 1.56 μm and 1.60 μm of A. Further, since the wavelength at which the value of the stimulated emission cross section and the value of the ESA cross section in the 1.6 μm band coincide is shifted to the longer wavelength side, the longer wavelength band of tellurite EDFA can be expanded. Therefore, this P ₂ O ₅
When a tellurite optical fiber containing the compound is used as a host of Er, a broadband tellurite EDFA with a flat gain, which has been difficult with the conventional one, can be realized. And if this EDFA is applied to a WDM communication system,
The transmission capacity can be dramatically increased, which can contribute to economical communication costs and enhanced functions of the communication system.

[Brief description of the drawings]

FIG. 1 (74) TeO _2- (16) ZnO- (6) N
1.5μm in _{a 2 O- (4) Bi 2} O 3 Er in the glass
A band emission _{spectrum, (74-X) TeO 2} - (16)
_{ZnO- (6) Na 2 O- (} 4) Bi 2 O 3 - (X) P
Er in ₂ O ₅ (X = 10, 15, 20 mol%) glass
FIG. 3 is a diagram showing a 1.5 μm band emission spectrum of the present invention.

FIG. 2 is a diagram showing an ESA cross section and a light emission cross section at a wavelength of 1.60 to 1.67 μm. In the figure, the core composition of the fiber 1 indicated by the solid line is (74) TeO ₂ − (16) Z
nO- (6) a _{Na 2 O- (4) Bi 2} O 3, the core composition of the fiber 2 shown by dotted lines, (59) TeO ₂ -
(16) ZnO- (6) Na 2 O- (4) Bi 2 O 3 -
(15) P ₂ O ₅ .

FIG. 3 is a schematic configuration diagram of an embodiment of a laser device according to the present invention.

[Explanation of symbols]

 1,5 mirror 2,4 amplifying optical fiber 3 tunable bandpass filter

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01S 3/10 H01S 3/10 Z 3/17 3/17 (72) Inventor Makoto Shimizu 3-chome Nishishinjuku, Shinjuku-ku, Tokyo 19-2 Nippon Telegraph and Telephone Corporation (72) Inventor Tadashi Sakamoto 19-2 Nishi Shinjuku 3-chome, Shinjuku-ku, Tokyo Japan (72) Inventor Toshiyuki Shimada Toshiyuki Nishi-Shinjuku 3-chome, Shinjuku-ku, Tokyo 19-2 Nippon Telegraph and Telephone Co., Ltd. (72) Inventor Yasutake Oishi 20-1 Sakuragaoka-cho, Shibuya-ku, Tokyo F-Term (in reference) 2NT050 AB37Z AC03 AD00 4G062 AA06 BB09 BB11 DA01 DB01 DB02 DC01 DD04 DE04 DF01 EA04 EB03 EC01 ED01 EE01 EF01 EG01 FA01 FB01 FC01 FD01 FE01 FF01 FG01 FH01 FJ01 FK02 FL02 GA03 GB01 GC01 GD07 GE01 HH01 HH03 HH05 HH07 HH09 KK NN KK NN20 5F072 AB07 AK06 AK10 JJ20 KK02 KK30 PP07 RR01 YY17

Claims (15)

[Claims] 1. P ₂ O ₅ in tellurite glass is 10 m
A tellurite glass for light amplification, characterized in that it is contained in an amount exceeding ol%. 2. TeO ₂ -ZnO-M ₂ O-L ₂ O _3-
Has a composition consisting of P ₂ O _5, in the composition, beyond 10 mol% amount of added P ₂ O _5, M is one or more alkali elements, L is Bi, La, Al, Ce, Yb, and Lu Tellurite glass for optical amplification, characterized in that it is at least one element selected from the group consisting of: 3. An optical fiber comprising a material glass having at least a core doped with erbium, wherein the material glass contains P ₂ O ₅ in a range exceeding 10 mol%. 4. An optical fiber made of a material glass, wherein the material glass is TeO ₂ -ZnO-M ₂ O-L ₂
It has a composition of O ₃ -P ₂ O ₅ , wherein P ₂
The added amount of O ₅ exceeds 10 mol%, M is one or more kinds of alkali elements, L is Bi, La, Al, Ce, Yb, L
An optical fiber comprising at least one element selected from u. 5. An optical amplifying medium comprising an optical fiber or an optical waveguide having a core glass and a clad glass, and light comprising an input means for inputting excitation light and signal light for exciting the optical amplifying medium to the optical amplifying medium. An optical amplifier, wherein at least one of the core glass and the clad glass is made of the tellurite glass for optical amplification according to claim 1. 6. An optical amplifying medium comprising an optical fiber or an optical waveguide having a core glass and a cladding glass, and light comprising: input means for inputting excitation light and signal light for exciting the optical amplifying medium to the optical amplifying medium. An optical amplifier, wherein at least one of the core glass and the cladding glass is made of the tellurite glass for optical amplification according to claim 2. 7. An optical amplifier comprising: an optical amplifying medium; and input means for inputting pumping light and signal light for exciting the optical amplifying medium to the optical amplifying medium, wherein the optical amplifying medium is defined in claim 3. An optical amplifier comprising an optical fiber. 8. An optical amplifier in which a plurality of optical amplifying media comprising an optical fiber in which at least the core is doped with erbium out of a glass core and a clad are arranged in series, and at least one of the core glass and the clad glass is provided. An optical amplifier comprising the optical amplifying tellurite glass according to claim 1. 9. An optical amplifier in which a plurality of optical amplifying media each composed of an optical fiber in which at least a core is doped with erbium out of a glass core and a clad are arranged in series, and at least one of the core glass and the clad glass is provided. Item 3. An optical amplifier comprising the tellurite glass for optical amplification according to Item 2. 10. A laser device having an optical resonator having a plurality of optical amplification media and an excitation light source, wherein at least one of the plurality of optical amplification media has an optical fiber or an optical waveguide having a core glass and a clad glass. A laser device, wherein at least one of the core glass and the clad glass is made of the tellurite glass for optical amplification according to claim 1. 11. A laser device having an optical resonator having a plurality of optical amplifying media and an excitation light source, wherein at least one of the plurality of optical amplifying media is an optical fiber or an optical waveguide having a core glass and a clad glass. A laser device, wherein at least one of the core glass and the clad glass is made of the tellurite glass for optical amplification according to claim 2. 12. A laser device in which a plurality of optical amplifying media each composed of an optical fiber in which erbium is added to at least one of a core and a clad made of glass are arranged in series, and at least one of the core glass and the cladding glass is provided. Item 7. A laser device comprising the tellurite glass for optical amplification according to Item 1. 13. A laser device in which a plurality of optical amplifying media composed of optical fibers in which at least the core is doped with erbium out of a glass core and a clad are arranged in series, wherein at least one of the core glass and the cladding glass is provided. Item 3. A laser device comprising the optical amplification tellurite glass according to Item 2. 14. A laser device having an optical amplification medium and an excitation light source, wherein the optical amplification medium comprises an optical fiber or an optical waveguide having a core glass and a clad glass, and at least one of the core glass and the clad glass. A laser device comprising the tellurite glass for optical amplification according to claim 1. 15. A laser device having an optical amplification medium and an excitation light source, wherein the optical amplification medium comprises an optical fiber or an optical waveguide having a core glass and a clad glass, and at least one of the core glass and the clad glass. A laser device comprising the tellurite glass for optical amplification according to claim 2.