JP2004307282A - Fluorine added quartz glass article and method of manufacturing the same - Google Patents

Fluorine added quartz glass article and method of manufacturing the same Download PDF

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Publication number
JP2004307282A
JP2004307282A JP2003104150A JP2003104150A JP2004307282A JP 2004307282 A JP2004307282 A JP 2004307282A JP 2003104150 A JP2003104150 A JP 2003104150A JP 2003104150 A JP2003104150 A JP 2003104150A JP 2004307282 A JP2004307282 A JP 2004307282A
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Prior art keywords
fluorine
quartz glass
glass article
chamber
added quartz
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Japanese (ja)
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Atsushi Abe
淳 阿部
Nobuyasu Mantoku
伸康 萬徳
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Shin Etsu Chemical Co Ltd
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Shin Etsu Chemical Co Ltd
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Priority to JP2003104150A priority Critical patent/JP2004307282A/en
Priority to EP04090131A priority patent/EP1466874B1/en
Priority to TW093109345A priority patent/TW200422270A/en
Priority to CA002463212A priority patent/CA2463212A1/en
Priority to CN2004100324191A priority patent/CN1550465B/en
Priority to US10/819,176 priority patent/US20040200240A1/en
Priority to AU2004201472A priority patent/AU2004201472A1/en
Priority to KR1020040024249A priority patent/KR20040087957A/en
Publication of JP2004307282A publication Critical patent/JP2004307282A/en
Pending legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
    • C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
    • C03B37/01453—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering for doping the preform with flourine
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/06—Doped silica-based glasses
    • C03B2201/07—Impurity concentration specified
    • C03B2201/075—Hydroxyl ion (OH)
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/06—Doped silica-based glasses
    • C03B2201/08—Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant
    • C03B2201/12—Doped silica-based glasses doped with boron or fluorine or other refractive index decreasing dopant doped with fluorine

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Thermal Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Glass Melting And Manufacturing (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorine added quartz glass article containing only a small quantity of OH groups and a method of manufacturing the same. <P>SOLUTION: In the heating of a porous glass preform under a fluorine gas atmosphere, the pressure in a chamber is made positive. The heating is carried out particularly for transparently vitrifying the preform at 1,350°C. The pressure in the chamber is a positive pressure of 10 to 500 Pa preferably to prevent sucking ambient air from a seal part. The moisture content in a gas supplied to the chamber is controlled to ≤3 ppm. The fluorine added quartz glass article containing ≤50 ppb OH group is manufactured using the method of manufacturing the fluorine added quartz glass article. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、光通信用ファイバの製造に好適なフッ素添加石英ガラス物品及びその製造方法に関する。
【０００２】
【従来の技術】
光通信用ファイバのなかには、所定の伝送特性を得るために、クラッド部にフッ素をドープした多孔質ガラス母材を製造し、これを線引きして屈折率分布の調整を行ったフッ素添加光ファイバが使用されている。
【０００３】
フッ素を添加した石英ガラスの製造には、多孔質ガラス母材を形成する際にフッ素をドープする方法と、多孔質ガラス母材を加熱・焼結して透明ガラス化する際にフッ素をドープする方法とが、一般的に行われている。
例えば、下記の特許文献１乃至３には、多孔質ガラス母材にフッ素を均一にドープする方法が提案されている。
【０００４】
これらの特許文献は、いずれもＨｅなどの不活性ガスにＣＦ４、ＳＦ６、ＳｉＦ４などのフッ素化合物を含む雰囲気中で保持することにより、多孔質ガラス母材中にフッ素をドープし、その後、焼結・透明ガラス化して、フッ素添加石英ガラスを製造している。
【０００５】
多孔質ガラス母材中にフッ素をドープするために使用されるフッ素化合物としては、通常、ＳｉＦ４が使用されている。しかしながら、ＳｉＦ４雰囲気下で焼結・透明ガラス化すると、得られたガラス中にＯＨ基が含有され、波長１３８５ ｎｍにおいて吸収を生じるという問題があった。
【０００６】
また、無水の光ファイバ母材を得るには、従来、多孔質ガラス母材中のＯＨ基を塩素と反応させることにより、例えば、多孔質ガラス母材を塩素ガスやＳＯＣｌ２ガス雰囲気下８００〜１０００℃で熱処理して脱水することが行われている（特許文献４参照）。
【０００７】
【特許文献１】特開２００２−４７０１３号公報
【特許文献２】特開２００２−６０２２８号公報
【特許文献３】特開２００２−１１４５２２号公報
【特許文献４】特開昭５６−７３６３６号公報
【発明が解決しようとする課題】
【０００８】
しかしながら、特許文献４に記載の方法で製造した光ファイバ母材であっても、ガラス中から十分にＯＨ基を除去することができず、波長１３８５ ｎｍに吸収が存在していた。
【０００９】
そこで、本発明の課題は、ＯＨ基含有量の少ないフッ素添加石英ガラス物品及びその製造方法を提供することである。
【００１０】
【課題を解決するための手段】
本発明のフッ素添加石英ガラス物品の製造方法は、多孔質ガラス母材をフッ素ガス雰囲気下で加熱処理する際に、チャンバー内の圧力を陽圧として行うことを特徴としている。なお、加熱処理は、特には透明ガラス化であり、１３５０℃以上で行われる。
【００１１】
チャンバー内の圧力は、１０〜５００ Ｐａの陽圧とし、また、チャンバーのシール部分から、外気の吸込みがないようにするのが好ましい。
チャンバー内に供給されるガスの水分量は３ｐｐｍ以下とされる。
本発明のフッ素添加石英ガラス物品は、上記フッ素添加石英ガラス物品の製造方法を用いて製造された、ＯＨ基含有量が５０ ｐｐｂ以下のものであることを特徴としている。
【００１２】
【発明の実施の形態】
上記したように、ＳｉＦ４雰囲気下で焼結・透明ガラス化すると、得られたガラス中にＯＨ基が含有される。しかしながら、Ｈｅ，Ｎ２，Ａｒ等の不活性ガス雰囲気下で透明ガラス化した場合には、ＯＨ基が含有されることはない。
【００１３】
そこで、幾つかの実験を行ったところ、ＳｉＦ４ガスが、透明ガラス化の際にチャンバー内の微量の水分と反応して、そのままガラス中に取り込まれることが分かった。そこで、チャンバー内の水分除去が最も重要であることを見出し、チャンバー内圧の管理、シール箇所の見直しを行って本発明を完成させた。
【００１４】
本発明のフッ素添加石英ガラス物品の製造方法について、図１を参照して、さらに詳細に説明する。
チャンバー１内に吊下げられた多孔質ガラス母材２は、ＳｉＦ４フッ素ガス雰囲気下、１３５０℃以上で１０〜５００ Ｐａの陽圧下において透明ガラス化が行われる。なお、チャンバー１内を１０〜５００ Ｐａの陽圧とする理由は、外気の吸込み防止のためである。
【００１５】
雰囲気ガスは、矢印で示されているように、チャンバー１の下方から、フッ素ドープ用のＳｉＦ４ガスとともにＨｅ，Ｎ２，Ａｒ等の不活性ガスが供給され、上方から所定の陽圧を保つように排出される。この間、多孔質ガラス母材２は、図示していない吊下げ・回転機構によりチャンバー１内で回転され、ヒーター４によって加熱され、透明ガラス化が行われる。
【００１６】
チャンバー１内を１０〜５００ Ｐａの陽圧とする理由は、１０ Ｐａ未満では外気の吸込み防止が不完全となり、５００ Ｐａを超えると、炉内圧とチャンバー内圧をバランスさせるのがむずかしくなるためである。このとき、チャンバー１内に供給されるガスの水分量は３ｐｐｍ以下とされる。この量を超えると、ＯＨ基を十分に除去できなくなる。
なお、チャンバー１内は、シール部分から外気の吸込みがないように、十分にシールするのが望ましい。
【００１７】
【実施例】
以下、実施例を挙げて説明するが、本発明はこれらに限定されず、様々な態様が可能である。
なお、下記の実施例１及び比較例１，２では、予め、ＶＡＤ法で作製した純石英ガラスからなる石英多孔質体を使用した。
【００１８】
（実施例１）
石英多孔質体を塩素ガス雰囲気下１１００℃で脱水後、温度を１４００℃に上げ、ＳｉＦ４１２ｍｏｌ％フッ素ガス雰囲気とし、透明ガラス化した。この間、チャンバー内圧は１００〜５００ Ｐａで変動し、陽圧を保持した。
チャンバー内に供給したガスの水分量は３ｐｐｍ以下とし、チャンバーのシール部分から、外気の吸込みがないようにして石英ガラスの製造を行った。
得られたフッ素添加石英ガラスのＯＨ基量をＩＲ分析したところ、図２に示したように、０．０５ ｐｐｍ以下となり、ＩＲ測定器の検出下限であった。
【００１９】
（比較例１）
石英多孔質体を塩素雰囲気下１１００℃で脱水後、温度を１４００℃に上げ、ＳｉＦ４１２ｍｏｌ％フッ素ガス雰囲気とし、透明ガラス化した。この間、チャンバー内圧は−１００〜９Ｐａで変動していた。チャンバー内に供給したガスの水分量は３ｐｐｍとした。得られたＦドープガラスのＯＨ基量をＩＲ分析したところ、図３に示したように、０．６ ｐｐｍ前後のＯＨ基を含有していた。
【００２０】
（比較例２）
石英多孔質体を塩素雰囲気下１１００℃で脱水後、温度を１４６０℃に上げ、Ｈｅ不活性ガス雰囲気とし、透明ガラス化してピュアシリカガラスを得た。この間、チャンバー内圧は−１００〜９Ｐａで変動していた。
得られたピュアシリカガラスのＯＨ基量をＩＲ分析した。図３に示したように、ＯＨ基はＩＲ測定器の検出下限値以下であった。
【００２１】
【発明の効果】
本発明によれば、容易にＯＨ基含有量の少ないフッ素添加石英ガラスが得られる。
【図面の簡単な説明】
【図１】焼結炉の一例を示す概略縦断面図である。
【図２】本発明の実施例１で得られたフッ素添加石英ガラス中のＯＨ基量を示すグラフである。
【図３】比較例１，２で得られたフッ素添加石英ガラス中のＯＨ基量を示すグラフである。
【符号の説明】
１……チャンバー、
２……多孔質ガラス母材、
３……炉、
４……ヒーター。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fluorine-doped quartz glass article suitable for manufacturing optical communication fibers and a method for manufacturing the same.
[0002]
[Prior art]
Among the optical communication fibers, a fluorine-doped optical fiber in which a porous glass base material in which a clad portion is doped with fluorine is manufactured and a refractive index distribution is adjusted by drawing the porous glass base material in order to obtain predetermined transmission characteristics. It is used.
[0003]
For the production of quartz glass to which fluorine is added, a method of doping fluorine when forming a porous glass base material and a method of doping fluorine when heating and sintering a porous glass base material to form a transparent glass The method is generally performed.
For example, Patent Documents 1 to 3 below propose a method of uniformly doping fluorine into a porous glass base material.
[0004]
In these patent documents, the porous glass base material is doped with fluorine by holding an inert gas such as He in an atmosphere containing a fluorine compound such as CF 4 , SF 6 , or SiF 4. Sintering and transparent vitrification to produce fluorine-added quartz glass.
[0005]
As a fluorine compound used for doping fluorine in the porous glass base material, SiF 4 is usually used. However, when sintering and transparent vitrification in a SiF 4 atmosphere, there is a problem that the obtained glass contains OH groups and absorbs at a wavelength of 1385 nm.
[0006]
Further, in order to obtain an anhydrous optical fiber preform, conventionally, an OH group in the porous glass preform is reacted with chlorine, for example, to form the porous glass preform in a chlorine gas or SOCl 2 gas atmosphere for 800 to 800 hours. Dehydration is performed by heat treatment at 1000 ° C. (see Patent Document 4).
[0007]
[Patent Document 1] JP-A-2002-47013 [Patent Document 2] JP-A-2002-60228 [Patent Document 3] JP-A-2002-114522 [Patent Document 4] JP-A-56-73636 [ Problems to be solved by the invention]
[0008]
However, even with the optical fiber preform manufactured by the method described in Patent Document 4, OH groups could not be sufficiently removed from the glass, and absorption was present at a wavelength of 1385 nm.
[0009]
Therefore, an object of the present invention is to provide a fluorine-added quartz glass article having a low OH group content and a method for producing the same.
[0010]
[Means for Solving the Problems]
The method for producing a fluorine-added quartz glass article of the present invention is characterized in that when the porous glass base material is heat-treated in a fluorine gas atmosphere, the pressure in the chamber is set to a positive pressure. Note that the heat treatment is particularly vitrification, and is performed at 1350 ° C. or higher.
[0011]
It is preferable that the pressure in the chamber is a positive pressure of 10 to 500 Pa, and that no outside air is sucked in from the sealed portion of the chamber.
The water content of the gas supplied into the chamber is 3 ppm or less.
The fluorine-added quartz glass article of the present invention is characterized by having an OH group content of 50 ppb or less, produced using the above-described method for producing a fluorine-added quartz glass article.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
As described above, when sintering and vitrification in a SiF 4 atmosphere, the obtained glass contains OH groups. However, when the vitrification is performed in an atmosphere of an inert gas such as He, N 2 , or Ar, no OH group is contained.
[0013]
Then, when some experiments were performed, it was found that the SiF 4 gas reacted with a small amount of water in the chamber during the vitrification and was taken into the glass as it was. Then, they found that the removal of water in the chamber was the most important, and completed the present invention by managing the pressure in the chamber and reviewing the sealing location.
[0014]
The method for producing the fluorine-containing quartz glass article of the present invention will be described in more detail with reference to FIG.
The porous glass base material 2 suspended in the chamber 1 is vitrified in a SiF 4 fluorine gas atmosphere at a temperature of 1350 ° C. or more and a positive pressure of 10 to 500 Pa. The reason why the pressure in the chamber 1 is set to a positive pressure of 10 to 500 Pa is to prevent outside air from being sucked.
[0015]
As shown in the arrow, as the atmosphere gas, an inert gas such as He, N 2 , or Ar is supplied together with the SiF 4 gas for fluorine doping from below the chamber 1, and a predetermined positive pressure is maintained from above. So that it is discharged. During this time, the porous glass base material 2 is rotated in the chamber 1 by a suspension / rotation mechanism (not shown), heated by the heater 4, and vitrified.
[0016]
The reason why the pressure in the chamber 1 is set to a positive pressure of 10 to 500 Pa is that if the pressure is less than 10 Pa, the prevention of outside air suction is incomplete, and if the pressure exceeds 500 Pa, it becomes difficult to balance the furnace pressure and the chamber pressure. . At this time, the water content of the gas supplied into the chamber 1 is set to 3 ppm or less. If this amount is exceeded, OH groups cannot be sufficiently removed.
It is desirable that the inside of the chamber 1 be sufficiently sealed so that no outside air is sucked from the sealed portion.
[0017]
【Example】
Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited thereto, and various embodiments are possible.
In the following Example 1 and Comparative Examples 1 and 2, a quartz porous body made of pure quartz glass produced by a VAD method in advance was used.
[0018]
(Example 1)
After the quartz porous body was dehydrated at 1100 ° C. in a chlorine gas atmosphere, the temperature was increased to 1400 ° C., and a 12 mol% SiF 4 fluorine gas atmosphere was used to form a transparent glass. During this time, the internal pressure of the chamber fluctuated between 100 and 500 Pa, and the positive pressure was maintained.
The water content of the gas supplied into the chamber was 3 ppm or less, and quartz glass was manufactured from the sealed portion of the chamber so that no outside air was sucked.
When the OH group content of the obtained fluorine-added quartz glass was analyzed by IR, it was 0.05 ppm or less as shown in FIG.
[0019]
(Comparative Example 1)
After the quartz porous body was dehydrated at 1100 ° C. in a chlorine atmosphere, the temperature was increased to 1400 ° C., and a 12 mol% SiF 4 fluorine gas atmosphere was used to form a transparent glass. During this time, the chamber internal pressure varied between -100 and 9 Pa. The water content of the gas supplied into the chamber was 3 ppm. IR analysis of the amount of OH groups in the obtained F-doped glass revealed that it contained about 0.6 ppm of OH groups as shown in FIG.
[0020]
(Comparative Example 2)
After the quartz porous body was dehydrated at 1100 ° C. in a chlorine atmosphere, the temperature was raised to 1460 ° C., the atmosphere was changed to a He inert gas atmosphere, and the glass was turned into a transparent glass to obtain pure silica glass. During this time, the chamber internal pressure varied between -100 and 9 Pa.
The OH group content of the obtained pure silica glass was analyzed by IR. As shown in FIG. 3, the OH group was below the lower limit of detection of the IR meter.
[0021]
【The invention's effect】
According to the present invention, a fluorine-containing quartz glass having a low OH group content can be easily obtained.
[Brief description of the drawings]
FIG. 1 is a schematic vertical sectional view showing an example of a sintering furnace.
FIG. 2 is a graph showing the amount of OH groups in the fluorinated quartz glass obtained in Example 1 of the present invention.
FIG. 3 is a graph showing the amount of OH groups in the fluoridated quartz glass obtained in Comparative Examples 1 and 2.
[Explanation of symbols]
1 ... chamber
2. Porous glass base material,
3 ... furnace
4 ... heater.

Claims (7)

多孔質ガラス母材をフッ素ガス雰囲気下で加熱処理する際に、チャンバー内の圧力を陽圧として行うことを特徴とするフッ素添加石英ガラス物品の製造方法。A method for producing a fluorine-added quartz glass article, comprising: performing a heat treatment of a porous glass base material in a fluorine gas atmosphere with a positive pressure in a chamber. 前記加熱処理が、透明ガラス化である請求項１に記載のフッ素添加石英ガラス物品の製造方法。The method for producing a fluoridated quartz glass article according to claim 1, wherein the heat treatment is transparent vitrification. 前記透明ガラス化の温度が１３５０℃以上である請求項２に記載のフッ素添加石英ガラス物品の製造方法。The method for producing a fluorine-added quartz glass article according to claim 2, wherein the temperature of the transparent vitrification is 1350 ° C or higher. 前記陽圧が、１０〜５００ Ｐａである請求項１乃至３のいずれかに記載のフッ素添加石英ガラス物品の製造方法。The method for producing a fluorine-added quartz glass article according to any one of claims 1 to 3, wherein the positive pressure is 10 to 500 Pa. チャンバーのシール部分から、外気の吸込みがないようにして行われる請求項１乃至４のいずれかに記載のフッ素添加石英ガラス物品の製造方法。The method for producing a fluorine-added quartz glass article according to any one of claims 1 to 4, wherein the method is performed such that outside air is not sucked from a sealed portion of the chamber. チャンバー内に供給されるガスの水分量が３ｐｐｍ以下である請求項１乃至５のいずれかに記載のフッ素添加石英ガラス物品の製造方法。The method for producing a fluorine-added quartz glass article according to any one of claims 1 to 5, wherein the gas supplied into the chamber has a moisture content of 3 ppm or less. 請求項１乃至６のいずれかに記載のフッ素添加石英ガラス物品の製造方法を用いて製造された、ＯＨ基含有量が５０ ｐｐｂ以下であることを特徴とするフッ素添加石英ガラス物品。A fluorine-added quartz glass article produced using the method for producing a fluorine-added quartz glass article according to any one of claims 1 to 6, wherein the OH group content is 50 ppb or less.
JP2003104150A 2003-04-08 2003-04-08 Fluorine added quartz glass article and method of manufacturing the same Pending JP2004307282A (en)

Priority Applications (8)

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JP2003104150A JP2004307282A (en) 2003-04-08 2003-04-08 Fluorine added quartz glass article and method of manufacturing the same
EP04090131A EP1466874B1 (en) 2003-04-08 2004-04-05 Method of manufacturing a fluorine-doped quartz glass article
TW093109345A TW200422270A (en) 2003-04-08 2004-04-05 Fluorine-doped quartz glass article and manufacturing method thereof
CA002463212A CA2463212A1 (en) 2003-04-08 2004-04-05 Fluorine-doped quartz glass article and manufacturing method thereof
CN2004100324191A CN1550465B (en) 2003-04-08 2004-04-07 Fluorine-doped quartz glass article and manufacturing method thereof
US10/819,176 US20040200240A1 (en) 2003-04-08 2004-04-07 Fluorine-doped quartz glass article and manufacturing method thereof
AU2004201472A AU2004201472A1 (en) 2003-04-08 2004-04-07 Fluorine-doped Quartz Glass Article and Manufacturing Method Thereof
KR1020040024249A KR20040087957A (en) 2003-04-08 2004-04-08 Fluorine-doped quartz glass article and manufacturing method thereof

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