JP2002321938A - Manufacturing method of optical amplification glass and optical amplification waveguide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical amplification glass having a bismuth oxide optical amplification waveguide without a fiber process. SOLUTION: This optical amplification glass is comprised of a matrix glass with 21-79 mol% Bi2 O3 , 7.6 mol% or more of alkali metal oxides, added in one or more elements selected from a group consisting of Er, Tm and Dy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a bismuth oxide optical amplification glass suitable for ion exchange and a method for manufacturing an optical amplification waveguide.

[0002]

2. Description of the Related Art For the purpose of application to an optical amplifier used in a wavelength division multiplexing optical communication system, etc., a core / cladding Er-doped bismuth oxide system having a short length, in which concentration quenching does not easily occur and a desired optical amplification can be obtained. Optical amplification glass fibers have been proposed.

[0003]

The light amplification glass used for the light amplification glass fiber is required not to be devitrified when the fiber is processed. On the other hand, such restrictions may reduce the optical amplification function of the optical amplification glass.

An object of the present invention is to provide a light amplification glass from which a bismuth oxide-based light amplification waveguide can be obtained without performing fiber processing, and a method for manufacturing the light amplification glass.

[0005]

According to the present invention, Bi ₂ O ₃ is converted to 2
Er, T are added to the matrix glass containing 1 to 79 mol%.
A light amplification glass to which at least one selected from the group consisting of m, Pr and Dy is added, wherein the matrix glass contains 7.6 mol% or more of an alkali metal oxide. . Further, the present invention provides a method for manufacturing an optical amplification waveguide, wherein the optical amplification glass is subjected to two-stage thermal ion exchange.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The optical amplification glass of the present invention (hereinafter referred to as the glass of the present invention) is usually made into an optical amplification waveguide by a two-step thermal ion exchange or the like, which will be described later. Connected with glass fiber. The glass of the present invention has a low-loss wavelength region (about 13
S ⁺ band (wavelength: 1450-1490 nm), S band (wavelength:
1490-1530 nm), C band (wavelength: 1530)
-1560 nm) or L band (wavelength: 1570-1)
(600 nm). Note that light having a wavelength of 900 to 1490 nm is usually used as the excitation light for performing optical amplification.

The glass of the present invention comprises a matrix glass and additional components, and the additional components may be Er, T
m, Pr, Dy and Yb. In addition, the content of the additional component is represented by using an element standard instead of an oxide standard, and is indicated by parts by mass with the matrix glass being 100 parts by mass. Hereinafter, parts by mass are simply referred to as parts.

In the glass of the present invention, when light amplification is performed in the C band or L band, Er, when light amplification is performed in the S ⁺ band or the S band, Tm is 130.
Pr or Dy for optical amplification in the 0 nm band
Is preferably contained.

The Er content is preferably 0.01 to 10 parts. If less than 0.01 part, C band or L
The light amplification factor in the band may be reduced. It is more preferably at least 0.1 part, particularly preferably at least 0.5 part. If it exceeds 10 parts, vitrification may be difficult. It is more preferably 5 parts or less, particularly preferably 4 parts or less.

[0010] The contents of Tm, Pr and Dy are each preferably 10 parts or less. If it exceeds 10 parts, vitrification may be difficult. It is more preferably 5 parts or less, particularly preferably 4 parts or less. T
m, Pr, or Dy
Is contained, it is preferable that each content is 0.01 part or more. More preferably 0.05 part or more,
Particularly preferably, it is at least 0.1 part.

Although not essential, the glass of the present invention may contain up to 10 parts of Yb in order to further increase the light amplification factor. If it exceeds 10 parts, vitrification becomes difficult. Preferably 5
Part or less. The effect of increasing the light amplification factor of Yb is remarkable when the glass of the present invention contains Er. When Yb is contained, its content is preferably 0.1%.
The amount is at least 01 part, more preferably at least 0.1 part, particularly preferably at least 0.5 part.

The glass of the present invention is disclosed in JP-A-6-19453.
It is suitable for use as a light amplification waveguide by applying a two-stage thermal ion exchange method known from JP-A No. 3 (1993) -1995. The two-stage thermal ion exchange method refers to a method in which a masked glass (glass to be ion-exchanged) is immersed in a melt A for ion exchange in a portion other than a portion where a waveguide is to be formed, and a high refractive index is formed in a portion not masked. A high-index ion-exchange layer (hereinafter referred to as a high-refractive-index layer), then immerse the glass in another ion-exchange melt B to move the high-refractive-index layer into the glass, and apply an electric field. Is what you do. For example, the glass contains Na, the ion exchange melt A is an AgNO ₃ melt, and the ion exchange melt B is a NaNO ₃ melt.

In the optical amplification waveguide manufactured by applying the two-stage thermal ion exchange method to the glass of the present invention, light having a wavelength of 1300 to 1650 nm and used for signal light of optical communication propagates in a single mode. Preferably it is possible. It is more preferable that excitation light having a wavelength of 900 to 1490 nm can also propagate in a single mode. Hereinafter, a wavelength range of 900 to 1650 nm including the wavelength ranges of the signal light and the pump light is referred to as a propagation wavelength band.

It is preferable that Δn _{633 obtained} by subtracting n ₆₃₃ of the glass to be ion-exchanged from refractive index n _{633 of the} high refractive index layer with respect to light having a wavelength of 633 nm is 0.002 to 0.55. Outside this range, it may be difficult to propagate light in the propagation wavelength band in a single mode. When the thickness of the high refractive index layer is 3 μm, Δn ₆₃₃ is 0.005 to 0.2
7. When the thickness is 4 μm, Δn ₆₃₃ is 0.005 to 0.5.
16. When the thickness is 5 μm, Δn ₆₃₃ is 0.005 to
It is preferably 0.10, respectively. The time for immersing the ion-exchanged glass in the ion-exchange melt for forming the high refractive index layer is preferably 10 hours or less, more preferably 6 hours or less.

In the present invention, the refractive index of the high refractive index layer is evaluated based on the refractive index for light having a wavelength of 633 nm which does not belong to the propagation wavelength band for the following reason. That is, when the refractive index for light in the propagation wavelength band is measured with high accuracy using a prism coupler described later, the thickness of the high refractive index layer must be more than 5 μm. Therefore, it is difficult to measure the refractive index of a high refractive index layer having a thickness of typically 2 to 5 μm with respect to light in a propagation wavelength band with high accuracy.
On the other hand, for high precision measurement of _n633 , the thickness of the high refractive index layer is 1.
5 μm is sufficient, and high precision measurement of n ₆₃₃ is possible.

The glass transition point _TG of the glass of the present invention is 36.
The temperature is preferably 0 ° C. or higher. If the temperature is lower than 360 ° C., the glass may be thermally damaged when a high-intensity laser beam is used as excitation light for optical amplification. In addition, when performing ion exchange, the temperature of the melt cannot be increased, and the ion exchange efficiency may decrease. T _G is preferably at least 380 ° C., more preferably at least 400 ° C., particularly preferably at least 420 ° C.

Next, for the matrix glass, mol%
Is simply described as% and will be described below. Bi ₂ O ₃ is essential. If it is less than 21%, the optical amplification rate decreases. It is preferably at least 24%. If it exceeds 79%, vitrification becomes difficult, _TG becomes low, or it becomes difficult to increase the refractive index of the ion exchange layer. It is preferably at most 70%, more preferably at most 60%, particularly preferably at most 50%, most preferably at most 40%.

The alkali metal oxide is an essential component for ion exchange. The total content of alkali metal oxides,
That is, Li ₂ O, Na ₂ O, K ₂ O, Rb ₂ O and F
It is preferable that the total content of r ₂ O is from 7.6 to 30 mol%. If it is less than 7.6%, it may be difficult to increase the refractive index of the ion exchange layer. It is more preferably at least 11%. If it exceeds 30%, vitrification tends to be difficult, T _G
May decrease, or the weather resistance may decrease. It is more preferably at most 20%, particularly preferably at most 15%.

It is preferable to contain at least one of Li ₂ O and Na ₂ O, and it is more preferable to contain Na ₂ O. When Na ₂ O is contained, its content is preferably 11 to 20%. If it is less than 11%, it may be difficult to increase the refractive index. More preferably, it is 11.5% or more. If it exceeds 20%, _TG may decrease or weather resistance may decrease. More preferably, it is 13.5% or less. In this case, Na ₂ O
Other alkali metal oxides may or may not be contained.

In the case where it is desired to make the glass of the present invention more difficult to devitrify, K ₂ O is preferably not contained.

The matrix glass is based on the following oxides: Bi ₂ O ₃ 21-79%, SiO ₂ 10-60%, Ga ₂ O ₃ 0-40%, Al ₂ O ₃ 0-30%, Li ₂ O _{0~30%, Na 2 O 0~30%} , K 2 O 0~30%, Rb 2 O 0~30%, Fr 2 O 0~30%, CeO 2 0~10%, 0~20% ZnO, 0~20% MgO, CaO 0~20%, SrO 0~20%, BaO 0~20%, GeO 2 0~20%, WO 3 0~10%, TeO 2 0~20%, TiO 2 0~10 %, ZrO ₂ 0-10%, SnO ₂ 0-10%, Y ₂ O ₃ 0-10%, and Li ₂ O + Na ₂ O + K ₂ O + Rb ₂ O
+ Fr ₂ O is preferably a 7.6 to 30 mol%.

Next, this preferred matrix glass will be described. Incidentally, it omitted for Bi ₂ O ₃ and alkali metal oxides described above. SiO ₂ is a network former and is essential. If it is less than 10%, vitrification becomes difficult or devitrification may occur during fiber processing. It is more preferably at least 20%. If it exceeds 60%, the light amplification rate will decrease, or the melting temperature during glass production will increase. It is more preferably at most 50%, particularly preferably at most 40%.

Ga ₂ O ₃ is not essential, but may be contained up to 40% in order to increase the wavelength width at which gain can be obtained or to suppress devitrification during fiber processing. 40
%, Crystals may be precipitated during glass production, and the transmittance of the glass may be reduced. It is preferably at most 30%, more preferably at most 25%. When containing Ga ₂ O ₃ ,
The content is preferably 1% or more. It is more preferably at least 5%, particularly preferably at least 10%.

Al ₂ O ₃ is not essential, but may be contained up to 30% to increase _TG . If it exceeds 30%, crystals may precipitate during glass production, and the transmittance of the glass may be reduced. More preferably 20% or less, particularly preferably 1%
0% or less. When Al ₂ O ₃ is contained, its content is preferably at least 0.1%. It is more preferably at least 1%, particularly preferably at least 2%.

CeO ₂ is not essential, but is contained up to 10% in order to prevent Bi ₂ O ₃ in the glass composition from being reduced during melting of the glass to precipitate as metallic bismuth, thereby reducing the transparency of the glass. May be. If it exceeds 10%, vitrification may be difficult, or yellow or orange coloring may become strong and the transmittance of the glass may decrease. It is preferably at most 1%, more preferably at most 0.5%, particularly preferably at most 0.3%. When CeO ₂ is contained, its content is preferably 0.01% or more. It is more preferably at least 0.05%, particularly preferably at least 0.1%. In order to avoid a decrease in the transmittance of the glass, the content of CeO ₂ is preferably less than 0.15%, and more preferably substantially no CeO ₂ .

ZnO, MgO, CaO, SrO and B
Although aO is not indispensable, each may contain up to 20% to stabilize the glass. If it exceeds 20%, the glass may be easily crystallized.

GeO ₂ is not essential, but has the effect of facilitating glass formation and increasing the refractive index.
%. If it exceeds 20%, the glass may be easily crystallized. It is preferably at most 10%, more preferably at most 5%. When containing GeO ₂ ,
The content is preferably 0.1% or more. More preferably, it is 1% or more.

WO ₃ is not essential, but may be contained up to 10% in order to increase the wavelength width at which gain can be obtained.
If it exceeds 10%, the light amplification rate may be reduced.

TeO ₂ is not essential, but may be contained up to 20% in order to increase the optical amplification factor. If it exceeds 20%, crystals may precipitate during glass production, and the transmittance of the glass may be reduced. It is preferably at most 10%, more preferably at most 5%. When TeO ₂ is contained, its content is preferably at least 1%, more preferably at least 2%.

TiO ₂ , ZrO ₂ , SnO ₂ and Y ₂ O ₃
Are not indispensable, but are each 1 to suppress devitrification at the time of glass production or to adjust the refractive index.
It may be contained up to 0%. If it exceeds 10%, the glass may be easily crystallized.

The preferred matrix glass consists essentially of the above components, but may contain other components as long as the object of the present invention is not impaired. The total content of the "other components" is preferably 10% or less.

Next, the "other components" will be described.
CdO, PbO, La ₂ O ₃ or the like may be contained to facilitate glass formation or to adjust the refractive index. Note that B ₂ O ₃ is preferably not contained because it may increase multiphonon relaxation.

[0033]

EXAMPLES In the column of Bi ₂ O ₃ to BaO in Table 1, mol% is shown.
In 100 parts by mass of the matrix glass of the composition shown in the display,
Glass having a composition to which Er and Yb were added in amounts shown in parts by mass in the same table was produced as follows. That is, the raw materials are prepared, mixed, put into a platinum crucible, melted while being kept at 1150 ° C. for 1 hour in the air atmosphere, and the obtained molten glass is poured out into a plate shape, kept at 450 ° C. for 4 hours, and then cooled to room temperature. Slow cooling for cooling was performed. Examples 1 to 3 are Examples and Example 4
7 are comparative examples.

The glass transition point T _G (unit: ° C.) of the glass thus produced was determined by differential thermal analysis at a wavelength of 130
Refractive indexes n ₁₃₀₄ and n for light having a wavelength of 4 nm and a wavelength of 633 nm
₆₃₃ was measured using a Metricon Model 2010 prism coupler (trade name). From this measurement result, it can be seen that n ₁₃₀₄ is about 0.98 times n ₆₃₃ .

The glass of Example 3 was 15 mm × 7 mm.
It was processed into a plate of mm × 2 mm, and the emission spectrum was measured as follows. That is, the glass is irradiated with light having a wavelength of 980 nm using a semiconductor laser diode having an output of 1 W, and a wavelength of 1500 to 1600 nm is obtained using a PbS detector.
The emission spectrum at m was measured. The result is shown by the thick line in FIG. The thin line in FIG. 1 is the emission spectrum of the light amplification glass obtained by adding 0.5 parts by mass of Er to 100 parts by mass of borosilicate glass (BK7) (IEEE).
E Photonics Technology Le
terts, Vol. 4,1041-1135,199
2 years).

[0036]

[Table 1]

Next, with respect to the glasses of Examples 1, 3, and 5, the glass was processed into a plate having a size of 20 mm × 15 mm × 1 mm, and immersed in a 370 ° C. AgNO ₃ melt for 1 to 6 hours. (Processes 1A4 to 5A6 in Table 2). Next, the treated glass was subjected to ultrasonic cleaning in ion-exchanged water, and then _n633 was measured. The results are shown in Table 2, and the immersion time is shown in the time column of the table.

Further, with respect to the glasses of Examples 2 and 3, AgN
A melt containing O ₃ and LiNO ₃ at a ratio of 1 mol: 1 mol was used in place of the AgNO ₃ melt, and the immersion time was changed to the time shown in the corresponding column of Table 3 in the same manner as the above treatment. After the treatment, the _n633 was measured after the ultrasonic cleaning (Table 3).
2B2 to 3B2).

The glass of Example 2 was made of AgNO._Three
And LiNO_ThreeIs contained in a ratio of 1 mol: 3 mol
AgNO_ThreeIt is used instead of the melt, and the above immersion time is shown.
3 except that the time is shown in the corresponding column.
After the ultrasonic cleaning. ₆₃₃Was measured (Table 3
Process 2C2, Process 2C4).

An electron beam microanalyzer (EPM)
Using A), the Ag concentration profile near the surface of the glass subjected to treatment 3B4 was measured. As a result, the thickness of the ion exchange layer was 4 μm.

[0041]

[Table 2]

[0042]

[Table 3]

[0043]

According to the present invention, a bismuth oxide-based optical amplification waveguide can be obtained without performing fiber processing, and a bismuth oxide-based optical amplification waveguide that can be manufactured without performing fiber processing can be obtained. .

[0044]

[Brief description of the drawings]

FIG. 1 is a diagram showing emission spectra of a light amplification glass and an Er-doped borosilicate glass of the present invention.

Continued on front page F-term (reference) 4G062 AA04 BB01 BB06 CC10 DA05 DA06 DB01 DB02 DB03 DB04 DC01 DD01 DE01 DE02 DE03 DE04 DF01 EA01 EA02 EA03 EA04 EA10 EB01 EB02 EB03 EB04 EC01 EC02 EC03 EC04 ED01 EE02 ED03 EF03 EF04 EG01 EG02 EG03 EG04 FA01 FA10 FB01 FB02 FB03 FC01 FC02 FC03 FD01 FD02 FD03 FD04 FE01 FE02 FE03 FF01 FG01 FH01 FJ01 FJ02 FJ03 FK01 FL01 FL02 FL03 GA04 GA05 H02 H01 GD01 H01 H HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ05 JJ07 JJ10 KK01 KK02 KK03 KK05 KK06 KK07 KK08 KK10 MM02 NN01 5F072 AB07 AB09 YY17

Claims (7)

[Claims] 1. A light amplification glass comprising a matrix glass containing 21 to 79 mol% of Bi ₂ O ₃ and one or more elements selected from the group consisting of Er, Tm, Pr and Dy added thereto. A light amplification glass in which the matrix glass contains at least 7.6 mol% of an alkali metal oxide. 2. The optical amplification glass according to claim 1, wherein Er is added in an amount of 0.01 to 10 parts by mass to 100 parts by mass of the matrix glass. 3. The method according to claim 1, wherein 0.01 to 10 parts by mass of Yb is added to 100 parts by mass of the matrix glass.
The optical amplification glass according to item 1. 4. A matrix glass in mole% based on the following _{oxides, Bi 2 O 3 21~79%,} SiO 2 10~60%, Ga 2 O 3 0~40%, Al 2 O 3 0~ _{30%, Li 2 O 0~30%} , Na 2 O 0~30%, K 2 O 0~30%, Rb 2 O 0~30%, Fr 2 O 0~30%, CeO 2 0~10%, ZnO 0-20%, MgO 0-20%, CaO 0-20%, SrO 0-20%, BaO 0-20%, GeO ₂ 0-20%, WO ₃ 0-10%, TeO ₂ 0-20% TiO ₂ 0 to 10%, ZrO ₂ 0 to 10%, SnO ₂ 0 to 10%, Y ₂ O ₃ 0 to 10%, and Li ₂ O + Na ₂ O + K ₂ O + Rb ₂ O
+ Optical amplifying glass according to claim 1, 2 or 3 Fr ₂ O is from 7.6 to 30 mol%. 5. The matrix glass according to claim 1, wherein said Na ₂ O is 11-20.
The optical amplification glass according to claim 1, which contains mol%. 6. The optical amplification glass according to claim 1, wherein the matrix glass does not contain K ₂ O. 7. A method for producing an optical amplification waveguide, comprising performing two-stage thermal ion exchange on the optical amplification glass according to claim 1.