JPS61201637A - Production of base material for optical fiber - Google Patents
Production of base material for optical fiberInfo
- Publication number
- JPS61201637A JPS61201637A JP3869085A JP3869085A JPS61201637A JP S61201637 A JPS61201637 A JP S61201637A JP 3869085 A JP3869085 A JP 3869085A JP 3869085 A JP3869085 A JP 3869085A JP S61201637 A JPS61201637 A JP S61201637A
- Authority
- JP
- Japan
- Prior art keywords
- base material
- glass
- fluorine
- porous glass
- bulk density
- 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
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
- 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]
- C03B37/01413—Reactant delivery systems
- C03B37/0142—Reactant deposition burners
-
- 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]
- C03B37/01486—Means for supporting, rotating or translating the preforms being formed, e.g. lathes
- C03B37/01493—Deposition substrates, e.g. targets, mandrels, start rods or tubes
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2207/00—Glass deposition burners
- C03B2207/50—Multiple burner arrangements
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (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〕
本発明は光7アイパ用母材の製造方法に関し、特にクラ
ッド部にフッ素を含む、高品質の石英系光ファイバ用母
材O11造方法に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a base material for an optical 7 eyer, and particularly relates to a method for manufacturing a base material O11 for a high-quality silica-based optical fiber containing fluorine in the cladding portion. .
第2脂に代表的な単一モード光ファイバの屈折率分布構
造を示す。従来このような屈折率分布を形成するために
は、屈折率を高める物itコア部に添加する方法が多く
堆られていた。屈折率を高める添加剤としてはG・0□
、 P2O5,*l、Osなどの酸化物が用いられるこ
とが多いが、これらの酸化物を用いると、■レイリー散
乱の増加によシ先の伝送損失が増加する、■ガラス母材
中に該酸化物に起因する気泡発生や結晶相析出などが起
シ易い、■ガラスの熱膨張係数が大きくなシガラス母材
が割れ易くなる、等の問題を生じる。したがって、ガラ
ス母材中に添加されるドーパント量は少ない方が望まし
い。The second layer shows the refractive index distribution structure of a typical single mode optical fiber. Conventionally, in order to form such a refractive index distribution, there have been many methods of adding substances that increase the refractive index to the core portion. G・0□ as an additive to increase the refractive index
, P2O5,*l, Os, etc. are often used; however, when these oxides are used, ■ the transmission loss at the tip increases due to an increase in Rayleigh scattering; Problems such as bubble generation and crystal phase precipitation caused by oxides are likely to occur, and (2) the glass base material, which has a large coefficient of thermal expansion, is likely to break. Therefore, it is desirable that the amount of dopant added to the glass base material be small.
このため、クラッド部に屈折率を低めるドーパント、た
とえばB20.、フッ素などを添加し、コアとクラッド
間の屈折率差を大きくする方法が増られることがある。For this reason, a dopant that lowers the refractive index is added to the cladding part, such as B20. In some cases, methods of increasing the refractive index difference between the core and the cladding by adding fluorine or the like may be used.
しかしながら、B2O5はシリカガラスの熱膨張係数を
大きくし、また長波長領域に固有の吸収損失を持つ。そ
こで屈折率低下成分としてはフッ素を用いることが望ま
しい〇
一方光ファイバの製造法として、火炎加水分解反応によ
シ、多孔質ガラス体を形成するWAD法(気相軸付は法
〕或はovpo法(外付けcvn法〕等は、生産性に優
れた経済的な方法として知られている。しかしながら、
MAD法或はovpo法のように火炎加水分解を利用し
た方法で石英ガラス中に十分な童のフッ素金象加するこ
とはきわめて困難である。たとえば、特開昭55−15
682号公報にはフッ素をガラス母材中に添加する方法
が記載されているが、この方法によればフッ素の添加に
よる屈折率の低下は、高々0.2〜0.3%程度にすぎ
ず添加されるフッ素の量に限界がある。However, B2O5 increases the coefficient of thermal expansion of silica glass and also has absorption loss specific to long wavelength regions. Therefore, it is desirable to use fluorine as the refractive index lowering component. On the other hand, as a manufacturing method for optical fibers, the WAD method (vapor phase attachment method), which forms a porous glass body by flame hydrolysis reaction, or The OVPO method (external CVN method) is known as an economical method with excellent productivity.However,
It is extremely difficult to add a sufficient amount of fluorine gold into quartz glass using a method using flame hydrolysis such as the MAD method or the OVPO method. For example, JP-A-55-15
Publication No. 682 describes a method of adding fluorine to a glass base material, but according to this method, the decrease in the refractive index due to the addition of fluorine is only about 0.2 to 0.3% at most. There is a limit to the amount of fluorine that can be added.
また−万では、特開昭55−67533号公報には、火
炎加水分解法で形成されたガラス微粒子の積層体tフッ
素化合物ガスの雰囲気中で加熱することによシ、効率的
にフッ素を添加する方法が提案されている。しかしなが
ら、上記公報に記載の方法では、ガラス微粒子積層体に
ほぼ均一にフッ素が添加されるので、フッ素のみを用い
て、第2図のような光導波路として十分な機能を有する
屈折率分布を形成することは―しい。Furthermore, in JP-A No. 55-67533, fluorine is efficiently added to a laminate of glass particles formed by flame hydrolysis by heating it in an atmosphere of fluorine compound gas. A method has been proposed. However, in the method described in the above publication, fluorine is added almost uniformly to the glass particle laminate, so only fluorine is used to form a refractive index distribution that has a sufficient function as an optical waveguide as shown in Figure 2. What to do is...
そこで、光導波路として十分な機能を有する屈折率分布
を形成し、かつ、生産性に優れた、火炎加水分解反応に
よる多孔質ガラス体全合成する方法を応用し九フッ素を
含む光ファイバ母材の製造方法として、第3因に模式的
に示した装置を用いた方法が考えられている。Therefore, we applied a method of total synthesis of a porous glass body using a flame hydrolysis reaction, which forms a refractive index distribution that has a sufficient function as an optical waveguide and has excellent productivity. As a manufacturing method, a method using the apparatus schematically shown in the third factor is considered.
回転、引上げ装置2に装着された、コア部に相当するガ
ラス棒1を徐々に上方に引上げつつ回転させると同時に
、該ガラス棒1の側面上にガラス微粒子合成用バーナー
3によシ生成させたガラス微粒子を堆積させてゆき、ク
ラッド部に相当する多孔質ガラス層4を形成する。ガラ
ス微粒子は、ガラス微粒子合成用バーナー3に、B2.
02及び51014などを同時に供給し、火炎加水分解
反応によシ形成する。5は反応容器、6は排気口である
。このようにして形成したガラス棒及び多孔質ガラス層
の複合体を、フッ素を含むガス雰囲気中で加熱すること
により、多孔質ガラス層にフッ素が取フ込まれるととも
に、該多孔質ガラス層は透明ガラス化し、第2図に示し
たような屈折率分布を有する光ファイバ用母材とするこ
とができる。A glass rod 1 corresponding to a core portion, which is attached to a rotating and pulling device 2, is rotated while being gradually pulled upward, and at the same time, a burner 3 for synthesizing glass particles is generated on the side surface of the glass rod 1. Glass particles are deposited to form a porous glass layer 4 corresponding to a cladding part. The glass fine particles are placed in a burner 3 for glass fine particle synthesis in B2.
02, 51014, etc. are simultaneously supplied and formed by flame hydrolysis reaction. 5 is a reaction vessel, and 6 is an exhaust port. By heating the thus formed composite of the glass rod and the porous glass layer in a gas atmosphere containing fluorine, fluorine is incorporated into the porous glass layer and the porous glass layer becomes transparent. It can be vitrified and used as an optical fiber preform having a refractive index distribution as shown in FIG.
しかしながら、上述の第3因装置?l−用いるこの方法
では、コア部に相当するガラス棒を予め所定の径に延伸
加工する際、しばしば水蒸気を含む雰囲気中で加熱され
る場合が多く、ガラス棒表面がOH基によって汚染され
易い。中でも水素原子を含む燃焼ガスにより形成される
火炎を用いて該ガラス棒を延伸加工する際に、ガラス棒
表面のOH基による汚染は著しい。さらに、クラッド部
に相当する多孔質ガラス層を形成する際にも、ガラス微
粒子合成用バーナーの火炎から生じる水蒸気により、ガ
ラス棒表面がOH基で汚染されることがある。However, the third factor device mentioned above? In this method, when the glass rod corresponding to the core portion is drawn to a predetermined diameter in advance, it is often heated in an atmosphere containing water vapor, and the surface of the glass rod is likely to be contaminated with OH groups. In particular, when the glass rod is stretched using a flame formed by combustion gas containing hydrogen atoms, contamination by OH groups on the surface of the glass rod is significant. Furthermore, when forming a porous glass layer corresponding to the cladding part, the surface of the glass rod may be contaminated with OH groups due to water vapor generated from the flame of the burner for synthesizing glass particles.
このように、コアに相当するガラス棒表面がOH基で汚
染された母材を紡糸し、光ファイバとした場合、該光フ
ァイバ中を伝搬する光がOH基の存在により吸収損失上
受け、伝送損失特性が劣化する。特に該光ファイバを単
一モードファイバとして用いる場合には、゛単一モード
光ファイバ中を伝搬する光のパワー分布は、クラッド部
まで広く拡がっているので、コアとクラッドの境界近傍
のOH基汚染層の影響が殊に著しく、伝送損失特性の劣
化が著しい。In this way, when a base material whose surface of a glass rod corresponding to the core is contaminated with OH groups is spun into an optical fiber, the light propagating through the optical fiber is affected by absorption loss due to the presence of OH groups, and transmission is reduced. Loss characteristics deteriorate. In particular, when the optical fiber is used as a single mode fiber, the power distribution of light propagating in the single mode optical fiber extends widely to the cladding, so OH group contamination near the boundary between the core and the cladding The influence of the layer is particularly significant, and the deterioration of transmission loss characteristics is significant.
ところで本発明者らは、鋭意研究の結果多孔質ガラス体
をフッ素を含む雰囲気中で加熱することにより多孔質ガ
ラス体内にフッ素を含有せしめる方法において、フッ素
の添加量は雰囲気中のフッ素或いはフッ素化合物濃度、
加熱温度及び多孔質ガラス体のカブ密度に大きく依存す
ることを見い出している。By the way, as a result of intensive research, the present inventors have found that in a method of incorporating fluorine into a porous glass body by heating the porous glass body in an atmosphere containing fluorine, the amount of fluorine added is determined by the amount of fluorine or fluorine compounds in the atmosphere. concentration,
It has been found that the heating temperature and the turn density of the porous glass body are highly dependent.
たとえはフッ素を添加した石英ガラスの屈折率減少率を
百分率で表わしたものをΔn(FJ とすると、
y4 25X10’
I an(F) l oc P X exp (
−−)T
となる。ここでPは雰囲気ガスとして用いるフッ素化合
物ガスの分圧、Rはボルツマン定数(1,987Caj
/lleg−nor )、丁は雰囲気の絶対温度を表わ
す。また、第4図にカサ密度対比屈折率差の関係を示す
。第4図の場合、1200’CSF6め分圧0.02
(他はHe)の炉の中にカナ密度の異なる多孔質ガラス
体を3時間保持したのち1650℃で透明ガラス化した
あと、石′へ英に対する屈折率の変化を求めたものであ
る。For example, if the refractive index reduction rate of fluorine-doped silica glass expressed as a percentage is Δn (FJ), then y4 25X10' I an (F) lo oc P X exp (
--) T. Here, P is the partial pressure of the fluorine compound gas used as the atmospheric gas, and R is the Boltzmann constant (1,987 Caj
/lleg-nor), D represents the absolute temperature of the atmosphere. Further, FIG. 4 shows the relationship between the bulk density and the refractive index difference. In the case of Figure 4, 1200' CSF6th partial pressure 0.02
Porous glass bodies with different densities were kept in a He (the others were He) furnace for 3 hours and then turned into transparent vitrification at 1650°C, and the change in refractive index relative to quartz was determined.
第4図より判るように同じ温度、時間、フッ素化合物ガ
ス分圧の雰囲気に多孔質ガラス母材をさらしても、多孔
質ガラス母材のカサ密度によって添加されるフッ素量に
大きな差が生じる。As can be seen from FIG. 4, even if the porous glass base material is exposed to an atmosphere of the same temperature, time, and fluorine compound gas partial pressure, there is a large difference in the amount of fluorine added depending on the bulk density of the porous glass base material.
そこで多孔質ガラス母材中に故意に半径方向にカサ密度
分布をつけることにより添加されるフッ素の霊に半径方
向、濃度分布、即ち屈折率分布を与えることが可能であ
る。Therefore, by intentionally creating a bulk density distribution in the radial direction in the porous glass base material, it is possible to give the added fluorine a concentration distribution, that is, a refractive index distribution, in the radial direction.
一万、多孔質ガラス母材の脱水性、即ち一定の脱水剤を
含むある温度雰囲気に多孔質母材tさらしそれ金さらに
高温で透明ガラス化した場合の残留OH量は多孔質ガラ
ス母材の力を密度に大きく依存しカサ密度が高いほど残
留OH量が多くなることはよく知られている。特に、上
記のごとくカサ密度分布を与えて多孔質ガラス母材に含
有されるフッ素量の濃度分布を形成する場合、カサ密度
の高い部分の脱水の方法VCに充分考慮する必要がめる
。10,000, the dehydration property of the porous glass base material, that is, the amount of residual OH when the porous base material is exposed to a certain temperature atmosphere containing a certain dehydrating agent and then turned into transparent vitrification at a high temperature is determined by the amount of residual OH of the porous glass base material. It is well known that force largely depends on density, and that the higher the bulk density, the greater the amount of residual OH. In particular, when forming the concentration distribution of the amount of fluorine contained in the porous glass base material by giving a bulk density distribution as described above, it is necessary to give sufficient consideration to the dewatering method VC of the portion with high bulk density.
本発明の目的は、以上の諸点を考慮し残留OH量が極め
て少なくコアが実質的に石英ガラス、クラッド部がフッ
素を含有した石英ガラスからなる伝送損失の極めて低い
光ファイバの製造方法を提供するところにある。In consideration of the above points, an object of the present invention is to provide a method for manufacturing an optical fiber with extremely low residual OH content, the core of which is substantially made of quartz glass, and the cladding portion of which is made of fluorine-containing quartz glass, and which has extremely low transmission loss. It's there.
本発明は出発材を増9囲む高カブ密度の多孔質ガラス層
と、該高カサ密度、多孔質ガラス層ヲ増り囲む低カサ密
度の多孔質ガラス層に、[出発材上にガラス微粒子を堆
積することにより形成したのち、上記出発材を取り除き
中空の多孔質ガラス体とし、該多孔質ガラス体に脱水、
フッ素添加、透明ガラス化の為の加熱処理金施すことに
より、半径方向にフッ素含有量の分布を有する中空透明
ガラス母材を形成し、その後該中空透明ガラス母材の内
部にガラス・エッチング剤を含むガスを流しつつ加熱処
at行うことによ51中空透明ガラス母材の内壁の平滑
化全行い、さらに加熱中実化することを特命とする光フ
ァイバ用母材の製造方法である。The present invention provides a porous glass layer with a high bulk density surrounding a starting material, and a porous glass layer with a low bulk density surrounding the high bulk density porous glass layer. After forming by depositing, the above starting material is removed to form a hollow porous glass body, and the porous glass body is subjected to dehydration,
By adding fluorine and applying heat treatment for transparent vitrification, a hollow transparent glass base material with a fluorine content distribution in the radial direction is formed, and then a glass etching agent is applied inside the hollow transparent glass base material. This is a method for producing an optical fiber preform in which the inner wall of the 51 hollow transparent glass preform is completely smoothed by heating it while flowing a containing gas, and the preform is heated to make it solid.
本発明の特に好ましい実施態様としては、該ガラスエツ
チング剤がフッ素或いはフッ素を含んだ化合物ガスであ
る上記方法が挙げられる。A particularly preferred embodiment of the present invention includes the above method in which the glass etching agent is fluorine or a compound gas containing fluorine.
以下にその詳細全説明する。なお、以下に述べる方法お
よび実施例は、本発明の例示にすぎず、また図面におけ
る各部の位置、相対的配置関係、大きさ、形状等は本発
明を何ら限定するものではない。The details will be explained below. The methods and examples described below are merely illustrative of the present invention, and the position, relative arrangement, size, shape, etc. of each part in the drawings do not limit the present invention in any way.
第1図は本発明に係る多孔質母材形成め方法の1実施態
様七示すもので、図中7は円筒状、または円柱状の耐火
性出発材であり、80回転引上装置に取り付けられてい
る。9は高カナ密度多孔質ガラス層11を形成するため
のバーナー、10は低かさ密度の多孔質ガラス層12’
1形成する為のバーナーであり、13は多孔質ガラス体
保持用石英パイプ、14は反応容器、15は排気口であ
る。16は、保持用石英パイプ管藺易的に出発材1に取
付る為のピンである。バーナー9及びバーナー10には
H2、炭化水素などの可燃性ガス、O及び5iGj4な
どの石英ガラス原料等が供給される。なおバーナー9で
は高カサ密度多孔質ガラス層を形成する為、ガラス微粒
子堆積表面温度が高くなるよう、その配置及び供給する
ガス原料の流量が調整される。各バーナーの火炎中では
ガラス原料の火炎加水分解反応によシ、ガラス微粒子が
形成され、このガラス微粒子が保持用石英パイプ130
部分から堆積され始め、出発材7を回転させつつ徐々に
上方に引上げていくことにより軸方向に出発材7の外周
部に堆積されていく。このようにして出発材7の外周部
にガラス微粒子を所定長堆積させることによシ出発材7
とこれを取り囲む多孔質ガラス母材が形成される。その
後該多孔質ガラス母材から出発材7を引抜くことにょシ
、保持用石英パイプ15に保持された円筒状(中空)の
多孔質ガラス母材會得ることができる。該中空多孔質ガ
ラス母材は内層部の上記バーナー9によって形成された
高カサfi度部11と、これを取り囲むバーナー10に
よって形成された低カサ密度部12からなっている。FIG. 1 shows one embodiment of the method for forming a porous base material according to the present invention. In the figure, 7 is a cylindrical or cylindrical refractory starting material, which is attached to an 80-turn pulling device. ing. Reference numeral 9 indicates a burner for forming the high density porous glass layer 11, and reference numeral 10 indicates a low bulk density porous glass layer 12'.
1 is a burner for forming the porous glass body, 13 is a quartz pipe for holding a porous glass body, 14 is a reaction vessel, and 15 is an exhaust port. 16 is a pin for easily attaching the holding quartz pipe to the starting material 1. The burners 9 and 10 are supplied with combustible gases such as H2 and hydrocarbons, O, quartz glass raw materials such as 5iGj4, and the like. Since the burner 9 forms a porous glass layer with a high bulk density, its arrangement and the flow rate of the gas raw material to be supplied are adjusted so that the surface temperature on which the glass fine particles are deposited becomes high. In the flame of each burner, glass particles are formed due to the flame hydrolysis reaction of the glass raw material, and these glass particles are attached to the holding quartz pipe 130.
The starting material 7 is deposited starting from the outer circumference of the starting material 7 in the axial direction by gradually pulling it upward while rotating the starting material 7. By depositing the glass fine particles to a predetermined length on the outer periphery of the starting material 7 in this way, the starting material 7
A porous glass base material surrounding this is formed. Thereafter, by pulling out the starting material 7 from the porous glass preform, a cylindrical (hollow) porous glass preform held by the holding quartz pipe 15 can be obtained. The hollow porous glass base material consists of a high bulk density part 11 formed by the burner 9 in the inner layer part and a low bulk density part 12 formed by the burner 10 surrounding this part.
なお、本発明の方法において用いられる出発材7の材質
としては、カーボン、シリコンカーバイド、石英ガラス
、アルミナ、ジルコニアなどガラス微粒子合成の際にバ
ーナー9.10の炎によシ腐食や変形の起シにくい材料
であることが必要である。特に、ジルコニアは、多孔質
ガラス体から出発材7を引き抜くことが容易であるため
、望ましい材料である。The starting material 7 used in the method of the present invention may be made of carbon, silicon carbide, quartz glass, alumina, zirconia, etc., which may cause corrosion or deformation due to the flame of the burner 9 or 10 during glass particle synthesis. It is necessary that the material is difficult to use. In particular, zirconia is a desirable material because it is easy to pull the starting material 7 out of the porous glass body.
また、第1園においてガラス微粒子合成用バーナーとし
て2本のみを用いた例を示しているが、必要に応じてバ
ーナ一本数を増す或いは、カサ密度調整用加熱バーナー
を設けることにより、よシ安定に多孔質母材形成が可能
となることもある。In addition, although an example is shown in which only two burners are used as glass particle synthesis burners in the first garden, stability can be improved by increasing the number of burners as necessary or by installing a heating burner for bulk density adjustment. It may also be possible to form a porous matrix.
次に以上のようにして作成した円筒状の多孔質ガラス母
材に脱水、フッ素添加透明化処理を施す。ここで多孔質
ガラス母材を円筒状に作成した理由は、前述したごとく
高カサ密度部の脱水が中実の多孔質ガラス母材では母材
外局部から多孔質ガラス層全通って拡散して(る脱水剤
によってのみ行われる為困難或いは長時間を要するため
である。すなわち円筒状にすることにより、内層の高カ
サ密度部が中空部を流れる脱水剤に直接接触することが
可能となり、脱水が効率的に行われる。Next, the cylindrical porous glass base material prepared as described above is subjected to dehydration and fluorine addition transparent treatment. The reason why the porous glass base material was made into a cylindrical shape is that, as mentioned above, in a solid porous glass base material, dehydration in the high bulk density area diffuses from the outside of the base material through the entire porous glass layer. (This is because it is difficult or takes a long time to carry out the dehydration process, as it can only be carried out using a dehydrating agent. In other words, by making it cylindrical, the high bulk density part of the inner layer can come into direct contact with the dehydrating agent flowing through the hollow part. is carried out efficiently.
第5図及びw46図は脱水、フッ素添加透明ガラス化の
方法の実施態様會示す図である。17は多孔質ガラス母
材を加熱するための円筒状に配置された炉1Bは炉心管
、19.20はガス導入口、21は排気口、22.22
’は多孔質ガラス母材を保持用石英パイプ13i介して
保持するための保持パイプ及び保持相棒であり、保持用
石英パイプ會ピンなどt用いて簡便に取り付けられるL
うになっている。保持相棒22・にはガスの通路23が
設けである。FIG. 5 and FIG. 46 are diagrams showing embodiments of the method of dehydration and fluorine addition to produce transparent vitrification. 17 is a cylindrically arranged furnace 1B for heating a porous glass base material; 19.20 is a gas inlet; 21 is an exhaust port; 22.22
' is a holding pipe and a holding partner for holding the porous glass base material through the holding quartz pipe 13i, and is easily attached using a holding quartz pipe pin, etc.
It's becoming a sea urchin. The holding partner 22 is provided with a gas passage 23.
まず、炉内を1100℃程度に保ちガス導入口19.2
0から脱水剤と希釈用ガス、たとえばCl2をHe を
流入せしめ、多孔質ガラス母材中に残留しているOH基
を十分増成く。この際高カサ密度部の内層部11が十分
C/2にさらされるように、第5因の方法ではガス導入
口20から流入されるガス流速を、下部のガス導入口1
9から導入されるガス流速よりも早くする。First, keep the inside of the furnace at around 1100℃ and gas inlet 19.2.
A dehydrating agent and a diluent gas such as Cl2 and He are introduced from 0 to sufficiently increase the OH groups remaining in the porous glass base material. At this time, in order to sufficiently expose the inner layer part 11 of the high bulk density part to C/2, in the method of the fifth factor, the gas flow rate flowing in from the gas inlet 20 is adjusted to the lower gas inlet 11.
The flow rate of the gas introduced from 9.
ま九第6図の方法では、下部のガス導入口19から流入
されたガスが多孔質ガラス母材中空部に流れ易くする目
的で、保持相棒22’の一部に母材中空部を流れてきた
ガスの通路23を設ける等の工夫によりより効率的に脱
水処理を施すことができる。In the method shown in Fig. 6, in order to facilitate the flow of gas into the hollow part of the porous glass base material from the lower gas inlet 19, a part of the holding partner 22' is made to flow through the hollow part of the base material. Dehydration processing can be carried out more efficiently by providing a gas passage 23 or the like.
その後、炉温を上昇させつつ、ガス導入口19からフッ
素化合物ガス例えば、SF6. OF4゜02F6.
SiF4など及びH6等の希釈用ガスを流入せしめ、フ
ッ素添加及び透明化処理を行う。炉温は1650℃程度
に上昇させれば完全に透明ガラス化せしめることができ
る。尚、フッ815加処理を透明ガラス化温度より低温
域で行いその後炉温を1650℃程度に上昇させ透明ガ
ラス化するというようにフッ素添加処理と透明ガラス化
処理を分離することも可能である。Thereafter, while increasing the furnace temperature, a fluorine compound gas such as SF6. OF4゜02F6.
A diluent gas such as SiF4 or H6 is introduced to perform fluorine addition and transparency treatment. Completely transparent vitrification can be achieved by raising the furnace temperature to about 1650°C. Note that it is also possible to separate the fluorine addition treatment and the transparent vitrification treatment, such as performing the fluorine 815 treatment at a temperature lower than the transparent vitrification temperature, and then increasing the furnace temperature to about 1650° C. to effect transparent vitrification.
このようにして得られた母材の模式的な径方同君折率分
布を第7図に示す。母材内層部は、多孔質ガラスの段階
で、カサ密度が高く、フッ素の添加量がきわめて少なく
なり、屈折率がほぼ純粋石英ガラスのものに等しい。FIG. 7 shows a schematic radial refractive index distribution of the base material thus obtained. At the stage of porous glass, the inner layer of the base material has a high bulk density, an extremely small amount of fluorine added, and a refractive index almost equal to that of pure silica glass.
なお、上記脱水フッ素添加透明ガラス化工程の説明に於
いては炉長がほぼ多孔質ガラス体の長さと同等以上であ
る均熱温度分布を持つ炉(均熱炉)の例を示したが、炉
長が短かい、リング状の炉(ゾーン炉)中を多孔質ガラ
ス母材を通過させていく方法においても何ら本発明の意
図するところを逸脱するものではない。In addition, in the above description of the dehydration fluoridation transparent vitrification process, an example of a furnace (soaking furnace) with a soaking temperature distribution in which the furnace length is approximately equal to or longer than the length of the porous glass body was shown, Even a method in which the porous glass base material is passed through a ring-shaped furnace (zone furnace) with a short furnace length does not deviate from the spirit of the present invention.
次に、以上で得られた中空透明ガラス母材を中実化する
方法について述べる。通常、管状石英パイプを中実化す
る際には、外周部から火炎或いは電気炉等で加熱し、場
合によっては中空部上減圧しつつ行われる。しかしなが
ら本発明の方法に於いては、中空の多孔質ガラス体を作
製する際、出発材全引抜く必要がある為、出発材を引抜
く際の傷などにより多少多孔質ガラス体内面の平滑度が
劣り、中実化の際の気泡発生の原因となり易い。さらに
透明化後から中実化に至るまで母材内層表面に水分等の
不純物の付着の可能性があり、伝送損失劣化の要因とな
シうる。Next, a method for solidifying the hollow transparent glass base material obtained above will be described. Normally, when a tubular quartz pipe is solidified, it is heated from the outer periphery using a flame or an electric furnace, and in some cases, the pressure is reduced above the hollow part. However, in the method of the present invention, when producing a hollow porous glass body, it is necessary to pull out the entire starting material. is inferior, and tends to cause bubbles to form during solidification. Furthermore, there is a possibility that impurities such as moisture may adhere to the surface of the inner layer of the base material from the time of transparency to the time of solidification, which may cause deterioration of transmission loss.
そこで本発明に於いては、中実化に先立って母材中空部
に、Fを含む化合物ガスなどのガラスエツチング剤必要
に応じて02などを流しつつ母材外部から母材全加熱す
ることにより母材内層表面の平滑化及び水分の除去上行
うことが有効である。また02は、ガラス内表面の02
欠陥を減少せしめることにより02欠陥に由来する伝送
特性の劣化を少なくする為に効果的である。Therefore, in the present invention, prior to solidification, a glass etching agent such as F-containing compound gas such as 02 is poured into the hollow part of the base material as necessary, and the base material is completely heated from the outside. It is effective to smooth the surface of the inner layer of the base material and remove moisture. Also, 02 is 02 on the inner surface of the glass.
By reducing the number of defects, it is effective to reduce deterioration in transmission characteristics caused by 02 defects.
ガラスエツチング剤としてはフッ素(F2) 或いは
CtF4.8F6. QC/2F2.02F6. BF
、、 NF、フッ素(F)を含む化合物ガスなどを用い
ることができる。As a glass etching agent, fluorine (F2) or CtF4.8F6. QC/2F2.02F6. BF
,, NF, a compound gas containing fluorine (F), etc. can be used.
このときの温度は9GO51300℃程度が一般的であ
る。また中実化は1800〜2000℃程度で行うこと
ができる。良だしこれらの温度は母材の大きさ等により
変ってくるものであυ何ら本発明を限定するものではな
い。The temperature at this time is generally about 9GO51300°C. Moreover, solidification can be performed at about 1800 to 2000°C. However, these temperatures vary depending on the size of the base material, etc., and do not limit the present invention in any way.
実施例1
直径15■のジルコニア管を出発材とし、第1図に示す
構成により、多孔質ガラス母材を作製した。内層(高カ
サ密度]多孔質ガラス層形成用のバーナー9には5LO
1a 50 CC7分、628137分、0□ 10ぶ
7分を供給し、外層(低カテ密度ン多孔質ガラス層形成
用バーナ10にはSiC/4B 00007分、H22
0J 7分、0250に7分を供給した。出発材f 5
0 rpwaで回転させつつ60鵬/時の速度で除々に
引上げることにより外径100111φ、内層部の淳さ
約5鵬のシ孔質ガラス母材を形成した。この際、外層部
低カサ密度部の平均カサ密度は0.25j1101’で
あシ、内層の高カサ密度部の平均力を密度は1.01/
rlyr’であった。該多孔質母材より出発材を引き抜
いたのち、第5図に示す構成により、脱水及びフッ素添
加透明化処理を行った。脱水は1100℃の温度で下部
ガス導入口19からはC12100C1;7分、He
7.51iJ1分に流し上部ガス導入口120からは
O/22J/分を流し3時間保持し脱水した。Example 1 A porous glass base material was prepared using a zirconia tube having a diameter of 15 square meters as a starting material and having the structure shown in FIG. 5LO for burner 9 for forming the inner layer (high bulk density) porous glass layer
1a 50 CC 7 minutes, 628137 minutes, 0□ 10bu 7 minutes was supplied, and the outer layer (low catastrophe density) SiC/4B 00007 minutes, H22 was supplied to the burner 10 for forming the porous glass layer.
0J 7 minutes, 0250 supplied 7 minutes. Starting material f5
A porous glass preform having an outer diameter of 100111φ and an inner layer thickness of about 5 mm was formed by gradually pulling up at a speed of 60 mm/hour while rotating at 0 rpm. At this time, the average bulk density of the low bulk density part of the outer layer is 0.25j1101', and the average force of the high bulk density part of the inner layer is 1.01/
It was rlyr'. After the starting material was extracted from the porous base material, it was subjected to dehydration and fluorine addition transparency treatment using the configuration shown in FIG. Dehydration was carried out at a temperature of 1100°C, using C12100C1; 7 minutes from the lower gas inlet 19;
7.51 iJ/minute was flowed, and O/22J/minute was flowed from the upper gas inlet 120 and held for 3 hours for dehydration.
しかるのち、温度を110Q℃から1600℃まで5℃
/分の上昇速度で上げていくとともに、下部ガス導入口
19からはSF 4 20 G DC7分、Ha8A/
分上部ガス導入口20からaH・0.21/分を流すこ
とにより、フッ素管多孔質母材に含有せしめつつ透明ガ
ラス化を行った。After that, the temperature was increased by 5℃ from 110Q℃ to 1600℃.
SF 4 20 G DC 7 minutes, Ha 8 A/min from the lower gas inlet 19.
By flowing 0.21/min of aH from the upper gas inlet 20, transparent vitrification was performed while the fluorine was contained in the porous base material of the fluorine tube.
得られた円筒状透明ガラス母材の屈折率分布を第8図に
示す図中aは[QIII、l)は14■、0は4ass
であった。又図中の%表示は純石英ガラスの屈折率との
差を示す。The refractive index distribution of the obtained cylindrical transparent glass base material is shown in FIG. 8. In the figure, a is [QIII, l) is 14■, and 0 is 4ass.
Met. Also, the percentage shown in the figure indicates the difference from the refractive index of pure silica glass.
該透明ガラス母材の両端に石英ダミーパイプ 。Quartz dummy pipes on both ends of the transparent glass base material.
を融着したのち1500℃の電気炉に挿入し石英ダず一
パイプの片端からsy6を300α/分o2.を5 G
G 007分、20分間保持し該母材内層部y o、
s am厚だけエツチングするとともに平滑化し、その
後炉温11900℃に上昇させ中実化した。その結果、
外径45■φコア径3■φコア一クラツド間の比屈折率
差0.29%(コア部に若干のフッ素が添加されコア部
の石英ガラスに対する比屈折率が0.03%であシ、ク
ラッド部の石英ガラスに対する比屈折率差は−0,32
%であった)の単一モード光ファイバ用プリフォーム會
得た。After welding, it was inserted into an electric furnace at 1500°C, and sy6 was heated at 300α/min o2. from one end of the quartz pipe. 5G
G 007 minutes, held for 20 minutes and the inner layer part of the base material yo,
It was etched by a thickness of sam and smoothed, and then the furnace temperature was raised to 11,900°C to solidify it. the result,
Outer diameter: 45 ■φ Core diameter: 3 ■φ Difference in relative refractive index between core and cladding: 0.29% (some fluorine is added to the core, and the relative refractive index of the core relative to quartz glass is 0.03%). , the relative refractive index difference of the cladding part with respect to quartz glass is -0.32
%) was obtained for a single mode optical fiber preform.
該プリフォームを外径125μmφになるよう紡糸しそ
の伝送損失を測定した結果波長1.3μmで0.45
dB/Ax、1.55amで0.28 (18/ 1m
13857111での01(吸収損失増は46B/la
1であり伝送損失にすぐれたものであった。The preform was spun to an outer diameter of 125 μmφ, and the transmission loss was measured to be 0.45 at a wavelength of 1.3 μm.
dB/Ax, 0.28 at 1.55am (18/1m
01 at 13857111 (absorption loss increase is 46B/la
1 and had excellent transmission loss.
比較例1
中央部にカサ密度〜1.Q &/傷3外径5■φの高カ
ナ密度部を有し咳高カサ密度部を*p囲むカサ密度〜0
.251/am3外径1408φの低カサ密度部を有す
る中実の多孔質ガラス体を形成したのちび多孔質ガラス
体を雰囲気ガスとしてC/22J/分、H・ 10ぶ7
分全供給している1100℃の電気炉中に6時間保持し
、加熱脱水処理したのちさらに温度を110G℃から1
600℃まで5℃/分の上昇速度で上げいくとともに、
雰囲気ガスとしてSF6200 (X: /分He8t
3/分に切替え、フッ素を多孔質母材に官有させつつ透
明ガラス化を行った。その結果フッ素は高カサ密度部に
は殆んど含有されず、低カサ密度部にのみ屈折率低下度
で0.3%の量だけ含有された母材を得ることができた
が叔母材の含有水分量を赤外分光度計で測定したところ
、高カサ密度部に〜200 ppmの水分が残留し、脱
水が全く行えなかった。Comparative Example 1 Umbrella density in the center ~1. Q&/Wound 3 has a high density area with an outer diameter of 5■φ and a density area surrounding the cough high density area *p ~ 0
.. 251/am3 A solid porous glass body having a low bulk density part with an outer diameter of 1408φ was formed, and the atmosphere gas was C/22 J/min, H・10bu7.
After being kept in an electric furnace at 1100°C for 6 hours and heated and dehydrated, the temperature was further increased from 110G°C to 1°C.
While increasing the temperature to 600℃ at a rate of 5℃/min,
SF6200 (X: /min He8t
3/min, and transparent vitrification was performed while allowing fluorine to be incorporated into the porous base material. As a result, we were able to obtain a base material in which almost no fluorine was contained in the high bulk density area, and only 0.3% of fluorine was contained in the low bulk density area in terms of the degree of decrease in refractive index. When the water content was measured using an infrared spectrometer, ~200 ppm of water remained in the high bulk density area, and dehydration could not be performed at all.
比較例2
実施例1と同様にして、中空透明ガラス体を形成したの
ち平滑化処理をしないで中実化したところ、母材中央部
に多数の気泡が残り、紡糸することができなかった。Comparative Example 2 When a hollow transparent glass body was formed in the same manner as in Example 1 and then solidified without smoothing, many air bubbles remained in the center of the base material, making spinning impossible.
比較例3
実施例1と同様にして中空透明ガラス体を形成したのち
平滑化処理する際02全流さなかったところ、紡糸後の
伝送損失時性測定においてすべての波長で約0.′Sd
B/A2I実施例のものよりロスが高かった。Comparative Example 3 A hollow transparent glass body was formed in the same manner as in Example 1, and then the 02 flow was not completely flowed during the smoothing treatment, and the transmission loss after spinning was measured to be about 0.0 at all wavelengths. 'Sd
The loss was higher than that of Example B/A2I.
以上の説明及び実施例の結果から明らかなように、本発
明の方法は多孔質ガラス母材の内層部と外層部のカサ密
度分布を調整することにより、母材中に含有されるフッ
素分布を制御し、加えて脱水、フッ素添加、透明化工程
及び中実化工程でのOH基付着残存を極力防止できるの
で、コアが石英、クラッドがフッ素を含む石英ガラスか
らなシOH基含有量の少ない高品質の石英系光ファイバ
用母材を得ることができる。As is clear from the above explanation and the results of the examples, the method of the present invention improves the distribution of fluorine contained in the porous glass base material by adjusting the bulk density distribution of the inner layer and outer layer of the porous glass base material. In addition, it is possible to prevent OH group adhesion as much as possible during dehydration, fluorine addition, transparency process, and solidification process, so the core is quartz and the cladding is made of quartz glass containing fluorine, so the content of OH groups is low. A high-quality silica-based optical fiber base material can be obtained.
4因面の簡単な説明
第1図 本発明に係る多孔質ガラス体の形成方法の実施
態様を示す模式図、
第2図 シングルモード光ファイバの屈折率分布の例を
示すグラフ、 、
第3図 フッ素tクラッド部に含有せしめた光ファイバ
用母材の従来法によるクラッ
ド層の製法の1例を示す図、
第4図 多孔質ガラス体のカサ密度と弗素添加量の関係
を示す図、
W45図及び第6図 本発明に係る多孔質ガラス母材の
脱水、弗素添加、透
羽化の各処理を行う方法の
実施態様を示す図、
第7図 本発明によって得られる中空透明ガラス母材の
屈折率分布のグラフ、
第8図 実施例によって得られた中空透明ガラス母材の
屈折率分布のグラフ。Brief explanation of the four factors Figure 1 A schematic diagram showing an embodiment of the method for forming a porous glass body according to the present invention, Figure 2 A graph showing an example of the refractive index distribution of a single mode optical fiber, Figure 3 Figure 4 shows an example of the conventional method for manufacturing a cladding layer of an optical fiber base material containing fluorine in the cladding part. Figure W45 shows the relationship between the bulk density of a porous glass body and the amount of fluorine added. and Fig. 6 is a diagram showing an embodiment of the method of dehydrating, fluoridating, and transparentizing a porous glass preform according to the present invention, and Fig. 7 is a refractive index of a hollow transparent glass preform obtained by the present invention. Distribution graph, FIG. 8 A graph of the refractive index distribution of the hollow transparent glass base material obtained in the example.
Claims (1)
該高カサ密度多孔質ガラス層を取り囲む低カサ密度の多
孔質ガラス層を、該出発材上にガラス微粒子を堆積する
ことにより形成したのち、上記出発材を取り除き、中空
の多孔質ガラス体とし、該多孔質ガラス体に脱水、フッ
素添加、透明ガラス化の為の加熱処理を施すことにより
、半径方向にフッ素含有量の分布を有する中空透明ガラ
ス母材を形成し、その後該中空透明ガラス母材の内部に
ガラス・エッチング剤を含むガスを流しつつ加熱処理を
行うことにより該中空透明ガラス母材の内壁の平滑化を
行い、さらに加熱中実化することを特徴とする光ファイ
バ用母材の製造方法。 2、ガラスエッチング剤がフッ素或いはフッ素を含む化
合物ガスである特許請求範囲第1項に記載の光ファイバ
用母材の製造方法。 3、該中空透明ガラス母材の内壁の平滑化に際し該中空
透明ガラス母材内部に流すガスがO_2を含有している
特許請求範囲第1項又は第2項に記載の光ファイバ用母
材の製造方法。[Claims] 1. A porous glass layer with a high bulk density surrounding the starting material;
After forming a low bulk density porous glass layer surrounding the high bulk density porous glass layer by depositing glass fine particles on the starting material, removing the starting material to form a hollow porous glass body, By subjecting the porous glass body to dehydration, fluorine addition, and heat treatment for transparent vitrification, a hollow transparent glass base material having a fluorine content distribution in the radial direction is formed, and then the hollow transparent glass base material An optical fiber preform characterized in that the inner wall of the hollow transparent glass preform is smoothed by heat treatment while flowing a gas containing a glass etching agent inside the preform, and the preform is made solid by heating. Production method. 2. The method for manufacturing an optical fiber preform according to claim 1, wherein the glass etching agent is fluorine or a compound gas containing fluorine. 3. The optical fiber preform according to claim 1 or 2, wherein the gas flowing inside the hollow transparent glass preform contains O_2 when smoothing the inner wall of the hollow transparent glass preform. Production method.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3869085A JPS61201637A (en) | 1985-03-01 | 1985-03-01 | Production of base material for optical fiber |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3869085A JPS61201637A (en) | 1985-03-01 | 1985-03-01 | Production of base material for optical fiber |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS61201637A true JPS61201637A (en) | 1986-09-06 |
JPH051221B2 JPH051221B2 (en) | 1993-01-07 |
Family
ID=12532292
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3869085A Granted JPS61201637A (en) | 1985-03-01 | 1985-03-01 | Production of base material for optical fiber |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS61201637A (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0311080A2 (en) * | 1987-10-07 | 1989-04-12 | Sumitomo Electric Industries Limited | Method for producing glass preform for optical fiber |
EP0738691A3 (en) * | 1990-11-09 | 1997-03-19 | Corning Inc | Method of forming an elongated glass article |
KR100310091B1 (en) * | 1999-10-18 | 2001-11-07 | 윤종용 | Apparatus for manufacturing silica glass for sol-gel process |
WO2003037808A1 (en) * | 2001-10-26 | 2003-05-08 | Heraeus Tenevo Ag | Method for producing a tube consisting of quartz glass, tubular semi-finished product consisting of porous quartz glass, and the use of the same |
JP2010202478A (en) * | 2009-03-05 | 2010-09-16 | Sumitomo Electric Ind Ltd | Method for manufacturing glass preform |
JP2011230988A (en) * | 2010-04-30 | 2011-11-17 | Sumitomo Electric Ind Ltd | Manufacturing method for glass preform |
JP2011230989A (en) * | 2010-04-30 | 2011-11-17 | Sumitomo Electric Ind Ltd | Manufacturing method for glass preform |
WO2014099645A1 (en) * | 2012-12-20 | 2014-06-26 | Corning Incorporated | Methods for forming optical fiber preforms with selective diffusion layers |
CN105174696A (en) * | 2015-08-11 | 2015-12-23 | 中国建筑材料科学研究总院 | Quartz glass roller making machine |
-
1985
- 1985-03-01 JP JP3869085A patent/JPS61201637A/en active Granted
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0311080A2 (en) * | 1987-10-07 | 1989-04-12 | Sumitomo Electric Industries Limited | Method for producing glass preform for optical fiber |
US5055121A (en) * | 1987-10-07 | 1991-10-08 | Sumitomo Electric Industries, Ltd. | Method for producing glass preform for optical fiber |
EP0738691A3 (en) * | 1990-11-09 | 1997-03-19 | Corning Inc | Method of forming an elongated glass article |
KR100310091B1 (en) * | 1999-10-18 | 2001-11-07 | 윤종용 | Apparatus for manufacturing silica glass for sol-gel process |
WO2003037808A1 (en) * | 2001-10-26 | 2003-05-08 | Heraeus Tenevo Ag | Method for producing a tube consisting of quartz glass, tubular semi-finished product consisting of porous quartz glass, and the use of the same |
JP2010202478A (en) * | 2009-03-05 | 2010-09-16 | Sumitomo Electric Ind Ltd | Method for manufacturing glass preform |
JP2011230988A (en) * | 2010-04-30 | 2011-11-17 | Sumitomo Electric Ind Ltd | Manufacturing method for glass preform |
JP2011230989A (en) * | 2010-04-30 | 2011-11-17 | Sumitomo Electric Ind Ltd | Manufacturing method for glass preform |
WO2014099645A1 (en) * | 2012-12-20 | 2014-06-26 | Corning Incorporated | Methods for forming optical fiber preforms with selective diffusion layers |
CN105174696A (en) * | 2015-08-11 | 2015-12-23 | 中国建筑材料科学研究总院 | Quartz glass roller making machine |
Also Published As
Publication number | Publication date |
---|---|
JPH051221B2 (en) | 1993-01-07 |
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