JPS63176325A - Production of glass preform for optical fiber - Google Patents
Production of glass preform for optical fiberInfo
- Publication number
- JPS63176325A JPS63176325A JP329487A JP329487A JPS63176325A JP S63176325 A JPS63176325 A JP S63176325A JP 329487 A JP329487 A JP 329487A JP 329487 A JP329487 A JP 329487A JP S63176325 A JPS63176325 A JP S63176325A
- Authority
- JP
- Japan
- Prior art keywords
- preform
- fluorine
- atmosphere
- gas
- sif4
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000011521 glass Substances 0.000 title claims abstract description 26
- 239000013307 optical fiber Substances 0.000 title claims description 18
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 29
- 238000010438 heat treatment Methods 0.000 claims abstract description 17
- 239000010419 fine particle Substances 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 38
- 238000004017 vitrification Methods 0.000 claims description 4
- 239000010453 quartz Substances 0.000 claims description 3
- 239000011737 fluorine Substances 0.000 abstract description 30
- 229910052731 fluorine Inorganic materials 0.000 abstract description 30
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 abstract description 29
- 229910004014 SiF4 Inorganic materials 0.000 abstract description 21
- ABTOQLMXBSRXSM-UHFFFAOYSA-N silicon tetrafluoride Chemical compound F[Si](F)(F)F ABTOQLMXBSRXSM-UHFFFAOYSA-N 0.000 abstract description 21
- 239000006260 foam Substances 0.000 abstract 1
- 238000005816 glass manufacturing process Methods 0.000 abstract 1
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 239000000463 material Substances 0.000 description 21
- 238000006243 chemical reaction Methods 0.000 description 10
- 238000005253 cladding Methods 0.000 description 10
- 239000000377 silicon dioxide Substances 0.000 description 9
- 239000000654 additive Substances 0.000 description 7
- 235000012239 silicon dioxide Nutrition 0.000 description 5
- 230000000996 additive effect Effects 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 238000007664 blowing Methods 0.000 description 3
- 238000000151 deposition Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 208000018459 dissociative disease Diseases 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003682 fluorination reaction Methods 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000012770 industrial material Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- 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
-
- 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
Landscapes
- 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)
- Manufacture, Treatment Of Glass Fibers (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、多孔質母材を用いた光ファイバーの母材の製
造方法に関するもので、特にフッ素（ト）を添加剤とし
て多量かつ高速で添加する光フアイバー母材の製造方法
に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing an optical fiber base material using a porous base material, and in particular, the present invention relates to a method for manufacturing an optical fiber base material using a porous base material, and in particular, a method for manufacturing an optical fiber base material using a porous base material. The present invention relates to a method of manufacturing an optical fiber base material.
従来、光ファイバはＭＡＤ法、ｏｖｐｏ法など様々力製
法で製造されているが、生産性・品質などの点で注目さ
れている。これらの方法は、まず火炎加水分解反応によ
シ、ガラス微粒子を生成し、回転する出発材上に次々と
堆積させ、棒状の多孔質プリフォームを作る。次にプリ
フォームを様々なガス雰囲気中で加熱処理し、脱水・溶
融ガラス化し、光フアイバ母材を得る。Conventionally, optical fibers have been manufactured using various methods such as the MAD method and the OVPO method, but these methods have attracted attention in terms of productivity and quality. These methods first generate glass particles through a flame hydrolysis reaction, and deposit them one after another on a rotating starting material to create a rod-shaped porous preform. Next, the preform is heat-treated in various gas atmospheres to dehydrate and melt it into vitrification to obtain an optical fiber base material.
さらにこの母材を紡糸して光ファイバを得るという方法
である。This method further involves spinning this base material to obtain an optical fiber.
光ファイバは、主として光の伝搬されるコア部と、その
周囲のクラッド部から構成されておシ、コア部の屈折率
をｎｌ 、クラッド部の屈折率をｎ２とすると、Ｎ、Ａ
（開口数）はＮ 、Ａ 、＝ｍ（ｎｌ＞ｎｚ）で定義
される（ｎｔｗｎ＋は平均値）。An optical fiber mainly consists of a core through which light propagates and a cladding around it.If the refractive index of the core is nl and the refractive index of the cladding is n2, then N, A
(Numerical aperture) is defined as N , A , = m (nl>nz) (ntwn+ is the average value).
シリカ（ｓｉｏ、）をベースとすると光ファイバでは、
（１）コアに屈折率を上げる添加剤を添加する方式、（
１１）クラッドに屈折率を下げる添加剤を添加する方式
、（Ｈｔ） （１）と（１１）の方式の合体方式、のい
ずれかの方式が用いられる。言うまでもなく、（１）で
はクラッド部が（１１）ではコア部がシリカである。In optical fibers based on silica (SIO),
(1) A method of adding an additive to the core to increase the refractive index, (
11) Either a method of adding an additive that lowers the refractive index to the cladding, or a method of combining methods (1) and (11) (Ht) is used. Needless to say, in (1), the cladding part is made of silica, and in (11), the core part is made of silica.
通常よく用いられる添加剤としては、Ｃ）ｅ０２ｔＰ２
０． 、 ｋｔ、０２．ＴｉＯ２（以上屈折率上昇用）
、またＢ２Ｏ３，Ｆ（以上屈折率下降用）等が挙げられ
る。第３図に波長ＩＩＬ５９μｍにおける石英系ガラス
の屈折率を示す。横軸はシリカ中の酸化物重量％を、縦
軸は屈折率（ｎα）および屈折率１ｍ％をあられす。［
出典：熊九、黒崎：”光伝送用材料１工業材料２７（１
９７９）、Ｐ３９］これらの添加剤のうち、フッ素は最
近になって注目されだした添加剤であって、ＶＡＤ法や
他の製法においても添加する方法が検討、開発されてい
る。Commonly used additives include C) e02tP2
0. , kt, 02. TiO2 (for increasing refractive index)
, B2O3, F (for lowering the refractive index), and the like. FIG. 3 shows the refractive index of silica glass at a wavelength IIL of 59 μm. The horizontal axis shows the weight percent of oxide in the silica, and the vertical axis shows the refractive index (nα) and the refractive index 1 m%. [
Source: Kumaku, Kurosaki: “Light transmission materials 1 Industrial materials 27 (1)
979), P39] Among these additives, fluorine is an additive that has recently begun to attract attention, and methods for adding it to the VAD method and other manufacturing methods are being studied and developed.
コア・クラッド間で同じ屈折率差を得たい場合に、一般
的にクラッドで屈折率を下げた、前述の（ｎ） Ｔｈよ
び（１１０の方式は、コア部に添加する添加剤量が全く
無いか、あるいは（１）の方式によるよシも少なくてす
む、という利点を有している。When it is desired to obtain the same refractive index difference between the core and cladding, the above-mentioned methods (n) Th and (110), in which the refractive index is generally lowered in the cladding, do not require any additive to be added to the core. Alternatively, the method (1) has the advantage of requiring less trouble.
このことは、高ＮＡ光ファイバにとって、コア部の添加
剤による吸収損失が低減されるという意味で有利である
。また、放射線照射下での伝送損失に優れた純シリカコ
ア光ファイバは（１１）の方式でしか作成できない。This is advantageous for high NA optical fibers in the sense that absorption losses due to additives in the core are reduced. Furthermore, a pure silica core optical fiber with excellent transmission loss under radiation irradiation can only be produced by the method (11).
このように、クラッド部の屈折率を下げる方式は有利な
特性をもつ。As described above, the method of lowering the refractive index of the cladding portion has advantageous characteristics.
特に、ＶＡＤ法の焼結工程において、フッ素を添加する
方法は、
■ 均一に添加できて、平担な屈折率分布を与えること
ができる。In particular, the method of adding fluorine in the sintering step of the VAD method is as follows: (1) It can be added uniformly and a flat refractive index distribution can be provided.
■ 処理速度が速い。すなわち数１００〜１ｋｇ程度の
多孔質プリフォームを数時間以内で処理・ガラス化でき
る。■ Fast processing speed. That is, a porous preform weighing several hundred to one kilogram can be processed and vitrified within several hours.
の２点において、特に他方式よりすぐれている。It is particularly superior to other methods in two respects.
しかしながら、従来技術においては、常圧下フッ素系ガ
ス１００チ雰囲気で多孔質プリフォームを加熱処理して
も、屈折率差で最大−Ｑ、７５チ程度しか添加されなか
った。また、他の製法、例えばプラズマ外付法と呼ばれ
る方法では、熱プラズマによる火炎を用いてガラス原料
を出発棒上に吹き付けて堆積させ、これを直接ガラス化
させるが、この際に同時にフッ素系ガスを添加して、フ
ッ素を添加しようとしても、屈折率差−１チを与える量
のフッ素系ガスを含有させた場合、その堆積速度はせい
ぜい０．１９／分であシ、かつ、添加量を増加させると
堆積速度が下がることが、知られている。However, in the prior art, even if a porous preform is heat-treated in an atmosphere of 100 fluorine-based gas under normal pressure, the maximum difference in refractive index is -Q, and only about 75 nitrides are added. In addition, in other manufacturing methods, such as the method called external plasma deposition method, glass raw materials are sprayed and deposited onto the starting rod using a flame generated by thermal plasma, and this is directly vitrified, but at the same time, fluorine-based gas is Even if an attempt is made to add fluorine by adding fluorine, if the fluorine-based gas is contained in an amount that gives a refractive index difference of -1 inch, the deposition rate is at most 0.19/min, and the addition amount is It is known that increasing the amount reduces the deposition rate.
加えて、ＶＡＤ法においてもプラズマ法においてもフッ
素を屈折率差で−（Ｌ５％以上添加しようとした場合、
得られたガラス母材中に気泡を残存せしめ、フッ素の添
加量を多くすればするほどこの傾向は大きくなるという
問題があった。In addition, in both the VAD method and the plasma method, when trying to add fluorine by -(L5% or more) due to the difference in refractive index,
There was a problem in that bubbles were allowed to remain in the obtained glass base material, and this tendency became more pronounced as the amount of fluorine added increased.
本発明は、上述の従来技術の欠点を解消すること、すな
わち、フッ素を添加した光フアイバ母材を得る方法にお
いて、気泡を残すことなくフッ素の添加量を向上するこ
と、またフッ素添加を高速で行えるようにすることを目
的とするものである。The present invention solves the above-mentioned drawbacks of the prior art, namely, to increase the amount of fluorine added without leaving bubbles in a method for obtaining a fluorine-doped optical fiber matrix, and to perform fluorine addition at high speed. The purpose is to make it possible.
本発明は石英を主成分とするガラス微粒子体の透明ガラ
ス化工程までに、該微粒子体を少なくとも一時期、実質
的にＳｉＦ４ ガスからなる１気圧を越えるガス雰囲気
中で加熱処理する工程を有しており、これに続いて実質
的にＳｉＦ４からなる１気圧以下のガス雰囲気中でさら
に高温に加熱して透明化を行うことを特徴とする光フア
イバ用ガラス母材の製造方法である。The present invention includes a step of heat-treating the glass particles containing quartz as a main component in a gas atmosphere of over 1 atm consisting essentially of SiF4 gas for at least a period of time before the step of making the glass particles transparent vitrification. This is followed by further heating to a high temperature in a gas atmosphere of 1 atm or less consisting essentially of SiF4 to make it transparent.
以下に本発明の基本となった知見及び本発明に到達した
経緯を詳細に述べる。Below, the findings that form the basis of the present invention and the circumstances that led to the present invention will be described in detail.
ガラス微粒子の多孔質プリフォームを熱処理する工程に
おいて、加圧ガス下で処理することで、反応効率を高め
うろことは容易に類推可能である。しかし、単に密閉し
た圧力容器を用い、内部にプリフォームとフッ素系ガス
を導入した加圧状態で熱処理を施しても良好なガラス体
を得ることば困難である。その理由は、１つは圧力容器
（炉心管）からの重金属汚染であシ、もう１つは雰囲気
ガス自体の熱分解による反応効率の低下である。It can be easily inferred that in the process of heat treating a porous preform of glass particles, the reaction efficiency is increased by treating it under pressurized gas. However, it is difficult to obtain a good glass body even if the preform and fluorine gas are introduced into the sealed pressure vessel and the heat treatment is performed under pressure. One reason is heavy metal contamination from the pressure vessel (furnace tube), and the other is a decrease in reaction efficiency due to thermal decomposition of the atmospheric gas itself.
さらにはフッ素系ガス中のフッ素以外の成分、例えばＣ
Ｆ４中のＣ’、ＳＦ６中のＳがガラス中に残り、気泡の
原因となることである。この点については、本発明を得
る過程において、ＣＦ４を使用してガラス中にフッ素を
添加せしめた場合、発生した気泡中の成分がＣＯ□、
Ｃｏからなっていた事実を確認できた。Furthermore, components other than fluorine in the fluorine-based gas, such as C
C' in F4 and S in SF6 remain in the glass and cause bubbles. Regarding this point, in the process of obtaining the present invention, when fluorine is added to the glass using CF4, the components in the generated bubbles are CO□,
We were able to confirm the fact that it was made of Co.
本発明者らはこのような知見に基き、本発明ではフッ素
化のためにＳｉＦ４ を用いる。このとき、石英ガラ
スとの反応は下記（１）の反応式３式％（）
ただし Ｓ：固体
ｇ：気体
のとおりであって、従来のＣＦ４や０２Ｆ、を用いる場
合とは異なり、Ｃ０２，ＣＯ等の余分なガスを発生しな
い。Based on this knowledge, the present inventors use SiF4 for fluorination in the present invention. At this time, the reaction with quartz glass is as shown in the following reaction formula (1), formula 3% () where S: solid g: gas, and unlike the conventional case of using CF4 or 02F, CO2, CO Do not generate excess gas such as
さらにＳｉＦ４ を加圧下で吹き流すことにより、発
熱炉からの汚染物質がプリフォームに達することなく運
び去られるので、プリフォームの清浄を保ち得ることも
見出した。Furthermore, it has been found that by blowing SiF4 under pressure, contaminants from the exothermic furnace are carried away without reaching the preform, thereby keeping the preform clean.
またこのように吹き流すことで常に新鮮なガスを供給す
ることによシ、最高の反応効率が維持できることが判明
した。これは下記（２）の反応式
％式％（２）
で表される解離反応を抑える効果があるためと考えられ
る。It has also been found that the highest reaction efficiency can be maintained by constantly supplying fresh gas by blowing in this way. This is thought to be due to the effect of suppressing the dissociation reaction expressed by the reaction formula (2) below.
上述の如く、ＳｉＦ４ を加圧下で吹き流すことは、常
に最高の反応効率を維持するうえでは最も重要な技術の
うちの一つであるが、反面しばしば焼結体中に気泡が残
るという現象が、依然として見られた。これは、常に最
高の反応効率を維持するために余剰のＳｉＦ４が供給さ
れているので、未反応のガスが気泡として残るためと考
えられた。一般に、雰囲気ガスの圧力が高い程、焼結後
のガラス体中に気泡が残留しやすくなることが知られて
いるので、気泡の残留を防ぐには、雰囲気ガスの圧力を
下げれば良いわけであるが、そうすると本発明の目的の
一方である、高濃度にフッ素を添加することが困難にな
ると予想された。As mentioned above, blowing SiF4 under pressure is one of the most important techniques to always maintain the highest reaction efficiency, but on the other hand, it often leaves bubbles in the sintered body. , was still seen. This was thought to be because unreacted gas remained as bubbles because excess SiF4 was always supplied to maintain the highest reaction efficiency. Generally, it is known that the higher the pressure of the atmospheric gas, the more likely bubbles remain in the glass body after sintering, so in order to prevent bubbles from remaining, it is sufficient to lower the pressure of the atmospheric gas. However, it was expected that this would make it difficult to add fluorine at a high concentration, which is one of the objectives of the present invention.
このようなジレンマを解決して、気泡残留をなくし、か
つフッ素添加量を向上できる方法について、本発明者ら
は鋭意検討した。その結果、まずガラス微粒子を堆積し
た多孔質プリフォームを加圧したＳｉＦ４雰囲気中、好
ましくは１気圧を越えるＳｉＦ４雰囲気中にて加熱処理
することによシ、該多孔質プリフォーム中にフッ素を多
量に添加できると同時に、該多孔質プリフォームの嵩密
度を高めて一定範囲に調整することができて、これを続
いて１気圧以下に圧力を下げたＳｉＦ４ 雰囲気中にて
更に温度を上昇させて加熱し透明化するという本発明の
方法によって、残留気泡の無い、高濃度にフッ素が添加
された石英ガラスを得ることができることを見出したの
である。The present inventors have conducted extensive studies on a method that can solve this dilemma, eliminate residual bubbles, and increase the amount of fluorine added. As a result, by first heating a porous preform on which glass fine particles have been deposited in a pressurized SiF4 atmosphere, preferably in a SiF4 atmosphere exceeding 1 atm, a large amount of fluorine is introduced into the porous preform. At the same time, the bulk density of the porous preform can be increased and adjusted within a certain range, and then the temperature is further increased in an SiF4 atmosphere with the pressure lowered to 1 atm or less. It has been discovered that by the method of the present invention, which involves heating and making transparent, it is possible to obtain quartz glass with no residual bubbles and to which fluorine is added at a high concentration.
また、上記の透明化以前の熱処理によって、多孔質プリ
フォームが収縮するが、その嵩密度が大きくなシすぎる
と、透明化後のガラス体に気泡が残り易く、一方嵩密度
が小さすぎると、−たん多孔質プリフォーム中に添加さ
れたフッ素が続く透明化の過程にて揮散して、得られた
透明ガラス体中のフッ素濃度が十分ではなくなってしま
う。そこで、透明化以前の熱処理工程を終えた多孔質プ
リフォームの嵩密度はＱ、３２〜１．７０９／ｃｍ”の
範囲であれば気泡残留もなく、フッ素の揮散もないので
好ましい。α５０〜１、１０９７ｃｍ３に調整すること
が特に好ましい。In addition, the porous preform shrinks due to the above-mentioned heat treatment before transparentization, but if the bulk density is too large, air bubbles tend to remain in the glass body after transparentization, while if the bulk density is too small, -Fluorine added to the porous preform volatilizes during the subsequent transparentization process, resulting in an insufficient fluorine concentration in the resulting transparent glass body. Therefore, it is preferable that the bulk density of the porous preform that has undergone the heat treatment process prior to transparentization be in the range Q of 32 to 1.709/cm, since there will be no residual air bubbles and no volatilization of fluorine. α50 to 1 , 1097 cm3 is particularly preferable.
ＷＡＤ法で得られた多孔質プリフォームの加熱処理雰囲
気（処理温度１２００℃、時間３時間）におけるＳｉＦ
４ ガスの分圧Ｐと、得られたガフス母材のシリカに対
する屈折率差△ｎの関係を、第４図に示す。これにより
、加圧雰囲気下ではフッ素はより効果的、多量にドープ
され、屈折率を下げることが判る。SiF in a heat treatment atmosphere (processing temperature 1200°C, time 3 hours) of a porous preform obtained by the WAD method
4. The relationship between the gas partial pressure P and the refractive index difference Δn of the obtained gaff base material with respect to silica is shown in FIG. This shows that under a pressurized atmosphere, fluorine is more effectively doped in a large amount and lowers the refractive index.
また、第５図に同プロセスの処理温度Ｔ（６）と屈折率
差△ｎの関係を示す。ＳｉＦ４の圧力Ｐが高く、処理温
度が高温であればあるほどフッ素添加量は増え屈折率差
は大きくなる。但し、実際問題としては、圧力が２０気
圧を越えるか、処理温度が１４００℃を越えると透明化
後のガラス体に気泡が残りやすい。また、温度が低すぎ
ると反応が１００チ起こらず非効率的なので、処理温度
としては８００℃以上が好ましい。Further, FIG. 5 shows the relationship between the treatment temperature T(6) and the refractive index difference Δn in the same process. The higher the pressure P of SiF4 and the higher the processing temperature, the greater the amount of fluorine added and the greater the difference in refractive index. However, as a practical matter, if the pressure exceeds 20 atmospheres or the treatment temperature exceeds 1400° C., bubbles tend to remain in the glass body after it has been made transparent. Furthermore, if the temperature is too low, 100 reactions will not occur and it will be inefficient, so the treatment temperature is preferably 800° C. or higher.
以上から５ｉＦ４９圧は１気圧を越えることが好ましく
、処理温度は８００℃以上で１４００℃以下にて処理し
て、多孔質プリフォームの嵩密度がｃＬ５２〜１．７０
９／ｍ’の範囲、特に好ましくは０．５ ［１〜１．１
０ ｆｌ／ｃｍ”の範囲になるように調整する。From the above, it is preferable that the 5iF49 pressure exceeds 1 atm, and the processing temperature is 800°C or higher and 1400°C or lower, so that the bulk density of the porous preform is cL52 to 1.70.
9/m', particularly preferably 0.5 [1 to 1.1
Adjust so that it is within the range of 0 fl/cm.
また前記のように透明化の際の雰囲気ガス圧力が高いほ
ど得られたガラス体中に気泡が残シやすいので、透明化
の際の圧力は低いほうが気泡残留の点では好ましいが、
実用上は１気圧以下の圧力において透明化すれば好結果
が得られるとわかった。この時の温度は１５００℃以上
が好ましく、特に好ましくは１４００℃以上である。In addition, as mentioned above, the higher the atmospheric gas pressure during transparentization, the more likely air bubbles will remain in the obtained glass body.
In practice, it has been found that good results can be obtained if the material is made transparent at a pressure of 1 atmosphere or less. The temperature at this time is preferably 1500°C or higher, particularly preferably 1400°C or higher.
本発明方法に用いる加熱処理装置の例を第１図および第
２図に示す。第１図および第２図において、１は支持棒
、２は多孔質プリフォーム、３は圧力容器、４は加熱部
、５および７は加熱装置、６は７−μ、８はガス配管を
示し、第２図の構成ではさらに９の圧力計、１０のガス
配管（流出部）、１１のパルプを備えている。これらは
あくまでも例示にすぎず、この構成に限定されるもので
はない。An example of a heat treatment apparatus used in the method of the present invention is shown in FIGS. 1 and 2. In Figures 1 and 2, 1 is a support rod, 2 is a porous preform, 3 is a pressure vessel, 4 is a heating section, 5 and 7 are heating devices, 6 is 7-μ, and 8 is a gas pipe. The configuration shown in FIG. 2 further includes 9 pressure gauges, 10 gas pipes (outflow sections), and 11 pulps. These are merely examples, and the configuration is not limited to this.
実施例１
第１図に示すような熱処理装置で純シリカ・プリフォー
ムをＳｉＦ４ ガス１００チ雰囲気でガラス化した。Ｓ
ｉＦ′、 ガスは五５気圧、温度は１１５０℃で２時
間保持されたあと、嵩密度ＣＬ ３８ ｆｌ／ｃｍ３の
多孔質体を１４００℃、５ｉＦ４１００チ１気圧雰囲気
中で溶融・ガラス化した。Example 1 A pure silica preform was vitrified in an atmosphere of 100 g of SiF4 gas using a heat treatment apparatus as shown in FIG. S
After the iF' gas was maintained at 55 atm and the temperature at 1150°C for 2 hours, the porous body with a bulk density CL 38 fl/cm3 was melted and vitrified in an atmosphere of 5iF4100 and 1 atm at 1400°C.
得られた負の屈折率は一１％であった。このガラスに石
英管をジャケットし、線引し光ファイバとしたところ、
不純物の混ムの少ない、低損失のファイバが得られた。The negative refractive index obtained was -1%. When this glass was jacketed with a quartz tube and drawn into an optical fiber,
A fiber with less impurities and low loss was obtained.
損失値は２ ｄＢ／ｋｍ（波長０．８５μｍにおいて）
であった。Loss value is 2 dB/km (at wavelength 0.85 μm)
Met.
実施例２
第２図に示すような熱処理装置を用いて、シリカ・ガラ
ス周囲にシリカ多孔質部を付着させたプリフォームを処
理した。温度は１１００℃、圧力２気圧を維持し、Ｓｉ
Ｆ４ ガスを２１７分の率で１時間流したところ、多孔
質体の嵩密度は［Ｌ ３５９／ｃｍ３となり得られた母
材のコア・クラッド間屈折率差は０．９％であった。母
材の透明ガラス化は１４５０℃以上の１気圧ＳｉＦ４雰
囲気中で行なった。この母材から得たファイバは損失値
が１． ｓ ｄＢ／ｃｒｎ（波長０８５μｍにおいて）
と高品質なものであった。Example 2 A preform in which a porous silica portion was attached around silica glass was treated using a heat treatment apparatus as shown in FIG. The temperature was maintained at 1100°C and the pressure was maintained at 2 atm.
When F4 gas was flowed at a rate of 217 minutes for 1 hour, the bulk density of the porous body was [L 359/cm3, and the difference in refractive index between the core and cladding of the obtained base material was 0.9%. Transparent vitrification of the base material was performed in a 1 atm SiF4 atmosphere at 1450°C or higher. The fiber obtained from this base material has a loss value of 1. s dB/crn (at wavelength 085 μm)
It was of high quality.
実施例３
第１図に示す熱処理装置を用いて、Δｎ＝２チのＧｅＯ
２を添加された高ＮＡガラスの周囲にシリカ多孔質部を
付着させたプリフォームを処理した。温度１２００℃、
圧力５気圧を維持してＳｉＦ４ をｓ Ｏｃｃ／分の
流量で１時間保持し、嵩密度を０．４ ａ ｆｉ／副３
とした。次いで１３００℃のＳｉＦ４ガス雰囲気（１気
圧）下で透明化し、クラッド部でΔｎ＝−１，２％を持
った、△ｎ：五２チの高ＮＡ母材を得た。この母材から
得たファイバの損失値は２． ｑ ａＢ／ｋｍ （波
長α８５μｍにおいて）であった。Example 3 Using the heat treatment apparatus shown in FIG.
A preform in which a porous silica portion was attached around a high NA glass doped with 2 was processed. Temperature 1200℃,
The pressure was maintained at 5 atm and SiF4 was maintained at a flow rate of s Occ/min for 1 hour, and the bulk density was 0.4 a fi/sub3.
And so. Next, it was made transparent under a SiF4 gas atmosphere (1 atm) at 1300°C to obtain a high NA base material with Δn=-1.2% in the cladding part and Δn:52. The loss value of the fiber obtained from this base material is 2. q aB/km (at wavelength α85 μm).
本発明は下記のような効果を奏する。 The present invention has the following effects.
１） ＳｉＦ４ガス雰囲気で、かつ１気圧を越える加
圧下で熱処理して、多孔質体の嵩密度をＱ、 ５２９／
ω３〜１．７０ ｆｊｌα３の範囲にすることにより、
シリカに比し１△ｎ１）１％の負の屈折率のガラスを得
ることが可能となった。1) Heat treated in a SiF4 gas atmosphere and under pressure exceeding 1 atm to reduce the bulk density of the porous body to Q, 529/
By setting it in the range of ω3 to 1.70 fjlα3,
It became possible to obtain a glass with a negative refractive index of 1Δn1)1% compared to silica.
２）高速でフッ素添加が可能となった。2) Fluorine addition is now possible at high speed.
３） ＳｉＦ４ ガスを加圧下で流しながら熱処理
す、ることによシ、フッ素の反応効率を落すことなく添
加することが可能となった。3) By performing heat treatment while flowing SiF4 gas under pressure, it has become possible to add fluorine without reducing reaction efficiency.
４）クラッドの△ｎを低くした形の、高ＮＡ光フアイバ
ー用母材、純シリカコア光フアイバー用母材の作成が容
易になった。4) It has become easier to create a base material for a high NA optical fiber and a base material for a pure silica core optical fiber with a low Δn of the cladding.
５）透明化処理を１気圧以下のＳｉＦ４雰囲気で行うこ
とにより、ガラス母材中に気泡を残すことなく、大量の
フッ素を添加することが可能になった。5) By performing the transparentization treatment in a SiF4 atmosphere of 1 atmosphere or less, it became possible to add a large amount of fluorine without leaving any bubbles in the glass base material.
さらに従来技術におけると同様、ＭＡＤ法の焼結工程で
フッ素を添加する利点、すなわち平担な屈折率分布およ
び処理速度における利点を有することは、言うまでもな
い。Furthermore, as in the prior art, it goes without saying that there are advantages of adding fluorine in the sintering step of the MAD method, that is, advantages in flat refractive index distribution and processing speed.
第１図および第２図は本発明に用いる加熱処理装置を説
明する図、第３図は石英系ガラスにおける、シリカ中酸
化物（重量％）と屈折率（ｎα）および屈折率差（△ｎ
）の関係を示すグラフ、第４図はＳｉＦ４ ガス分圧と
屈折率差１△ｎ１の関係を示すグラフ、第５図は屈折率
差Δｎの処理温度依存性を示すグラフである。Figures 1 and 2 are diagrams explaining the heat treatment apparatus used in the present invention, and Figure 3 is silica-based oxide (wt%), refractive index (nα), and refractive index difference (△n
), FIG. 4 is a graph showing the relationship between the SiF4 gas partial pressure and the refractive index difference 1Δn1, and FIG. 5 is a graph showing the processing temperature dependence of the refractive index difference Δn.
Claims (2)
化工程までに、該微粒子体を少なくとも一時期、実質的
にＳｉＦ＿４ガスからなる１気圧を越えるガス雰囲気中
で加熱処理する工程を有しており、これに続いて実質的
にＳｉＦ＿４からなる１気圧以下のガス雰囲気中でさら
に高温に加熱して透明化を行うことを特徴とする光フア
イバ用ガラス母材の製造方法。(1) Before the transparent vitrification process of the glass fine particles mainly composed of quartz, the fine particles are heat-treated for at least one period in a gas atmosphere of more than 1 atmosphere consisting essentially of SiF_4 gas. A method for producing a glass preform for an optical fiber, which is then further heated to a high temperature in a gas atmosphere of 1 atm or less consisting essentially of SiF_4 to make it transparent.
ガス雰囲気中でガラス微粒子体を加熱処理することによ
り、該ガラス微粒子体の嵩密度を０．３２ｇ／ｃｍ＾３
〜１．７０ｇ／ｃｍ＾３の範囲とする特許請求の範囲第
（１）項記載の光フアイバー用ガラス母材の製造方法。(2) By heating the glass particulate body in a gas atmosphere exceeding 1 atm consisting essentially of SiF_4 gas, the bulk density of the glass particulate body is reduced to 0.32 g/cm^3
A method for producing a glass preform for optical fiber according to claim (1), wherein the preform is in a range of 1.70 g/cm^3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62003294A JPH089487B2 (en) | 1987-01-12 | 1987-01-12 | Method for producing glass base material for optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62003294A JPH089487B2 (en) | 1987-01-12 | 1987-01-12 | Method for producing glass base material for optical fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63176325A true JPS63176325A (en) | 1988-07-20 |
| JPH089487B2 JPH089487B2 (en) | 1996-01-31 |
Family
ID=11553362
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62003294A Expired - Lifetime JPH089487B2 (en) | 1987-01-12 | 1987-01-12 | Method for producing glass base material for optical fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH089487B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006199517A (en) * | 2005-01-18 | 2006-08-03 | Furukawa Electric Co Ltd:The | Method of manufacturing optical fiber preform |
| JP2012246157A (en) * | 2011-05-26 | 2012-12-13 | Ohara Inc | Method for producing synthetic silica glass and the synthetic silica glass |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| PT105474A (en) | 2011-01-10 | 2012-11-27 | Univ Lisboa | UNDERWATER SOUND GENERATOR |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6090843A (en) * | 1983-10-20 | 1985-05-22 | Sumitomo Electric Ind Ltd | Manufacture of glass base material for optical fiber |
| JPS60239337A (en) * | 1984-05-15 | 1985-11-28 | Sumitomo Electric Ind Ltd | Preparation of parent glass material for optical fiber |
| JPS60255638A (en) * | 1984-05-31 | 1985-12-17 | Sumitomo Electric Ind Ltd | Production of parent material for optical fiber |
-
1987
- 1987-01-12 JP JP62003294A patent/JPH089487B2/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6090843A (en) * | 1983-10-20 | 1985-05-22 | Sumitomo Electric Ind Ltd | Manufacture of glass base material for optical fiber |
| JPS60239337A (en) * | 1984-05-15 | 1985-11-28 | Sumitomo Electric Ind Ltd | Preparation of parent glass material for optical fiber |
| JPS60255638A (en) * | 1984-05-31 | 1985-12-17 | Sumitomo Electric Ind Ltd | Production of parent material for optical fiber |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006199517A (en) * | 2005-01-18 | 2006-08-03 | Furukawa Electric Co Ltd:The | Method of manufacturing optical fiber preform |
| JP2012246157A (en) * | 2011-05-26 | 2012-12-13 | Ohara Inc | Method for producing synthetic silica glass and the synthetic silica glass |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH089487B2 (en) | 1996-01-31 |
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