JP3485673B2 - Dehydration and sintering device for porous preform for optical fiber - Google Patents
Dehydration and sintering device for porous preform for optical fiberInfo
- Publication number
- JP3485673B2 JP3485673B2 JP11956595A JP11956595A JP3485673B2 JP 3485673 B2 JP3485673 B2 JP 3485673B2 JP 11956595 A JP11956595 A JP 11956595A JP 11956595 A JP11956595 A JP 11956595A JP 3485673 B2 JP3485673 B2 JP 3485673B2
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- preform
- sintering
- dehydration
- base material
- 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.)
- Expired - Lifetime
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
- C03B37/0146—Furnaces therefor, e.g. muffle tubes, furnace linings
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
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)
- Glass Melting And Manufacturing (AREA)
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は光ファイバ用ガラス母材
の製造に用いられる光ファイバ用多孔質母材の脱水・焼
結装置に関する。
【０００２】
【従来技術】従来、光ファイバ用ガラス母材を製造する
一般的な方法は以下の通りである。まず、ＶＡＤ法や外
付け法などにより所望の屈折率分布および所望のサイズ
の光ファイバ用多孔質母材を合成する。次いで、脱水・
焼結であるが、通常は脱水・焼結には共通の炉（以下、
脱水・焼結炉という）を用いる。具体的には、前記光フ
ァイバ用多孔質母材を所定の雰囲気・温度とした炉内に
て加熱処理して脱水させ、続いて焼結に適した所定条件
に炉内雰囲気・温度を変更したのち、加熱処理して焼結
させて光ファイバ用ガラス母材を製造する。
【０００３】光ファイバ用多孔質母材の脱水・焼結装置
は、図２に示すように、脱水・焼結のための加熱処理を
行う脱水・焼結炉１と脱水・焼結処理を施す光ファイバ
用多孔質母材７を把持するための母材把持部８からな
る。具体的には、脱水・焼結炉１は、炉心管２と、該炉
心管２の外周に位置し内部に発熱体４を有する炉体３か
らなる。前記炉心管２の上部には母材導入口５、下部に
は各処理に適した雰囲気ガスを供給する雰囲気ガス供給
口６が設けられている。また、脱水・焼結処理を施す光
ファイバ用多孔質母材７を前記炉心管２内の所定位置に
保持するための母材把持部８が、前記脱水・焼結炉１の
上方に配置されている。
【０００４】前記母材把持部８は、光ファイバ用多孔質
母材７と共に脱水の際に、塩素を含む雰囲気中、1500℃
〜1600℃という過酷な条件に曝されるため、石英ガラス
にて形成されている。また、前記石英ガラスは、不透明
石英ガラスでは物理的な強度が不足するため、透明石英
ガラスが用いられている。
【０００５】近年、光ファイバは通信分野などにおいて
需要が飛躍的に伸び、その結果として生産性の向上が望
まれている。現状況下での光ファイバ生産の律速段階
は、光ファイバ用ガラス母材から光ファイバに線引する
段階であり、生産性を向上させるには、線引に関わる様
々な時間を短縮化することが必要である。線引時間の短
縮化の方法の一つとして、線引される光ファイバ用ガラ
ス母材を大型化し、一つの光ファイバ用ガラス母材から
光ファイバを従来よりも長く連続線引する方法がある。
この方法によれば、１本の光ファイバ用ガラス母材から
線引きされる光ファイバ長が長くなるので、光ファイバ
用ガラス母材の段替え回数を少なくできるため、段替え
に伴う様々な作業を省略でき、生産性が向上する。ま
た、融着接続などを必要としない長距離の光ファイバが
得られ、伝送損失の小さい光ファイバを得ることが可能
となる。
【０００６】現在、線引用の光ファイバ用ガラス母材の
前駆体である光ファイバ用多孔質ガラス母材自体の大型
化は技術の進歩によってなし得ている。しかしながら、
続く脱水・焼結が従来と同様の設備ではうまく行かず、
大型の光ファイバ用ガラス母材を得ることが難しかっ
た。すなわち、脱水・焼結炉自体は、大型の光ファイバ
用多孔質母材に併せて大型化すれば良かったが、脱水・
焼結炉と同一の比率で大型化しただけの母材保持部で
は、前記大型の光ファイバ用多孔質母材を保持しきれな
いという問題がある。具体的には、該母材保持部の粘度
が低下して、その形状が変形するために光ファイバ用多
孔質母材の位置を正確に制御することができなくなり、
精度良く脱水ガラス化することができないことや、前記
母材保持部が伸びきって切れてしまい、光ファイバ用多
孔質母材が落下してしまうことがあった。なお、従来の
母材保持部も光ファイバ用多孔質母材を脱水・焼結する
際に同様に粘度が低下していたが、光ファイバ用多孔質
母材の重量が小さかったため、母材保持部の軟化変形に
は至っていなかった。
【０００７】
【発明が解決しようとする課題】そこで、光ファイバ用
多孔質母材を脱水・焼結炉内に保持する母材保持部の改
良、具体的には大型の光ファイバ用多孔質母材の脱水・
焼結処理の間中、該光ファイバ用母材の保持に耐えうる
母材保持部の改良が急がれていた。
【０００８】
【課題を解決するための手段】前述した課題を解決すべ
く、本発明は、炉心管と、内部に発熱体を有し前記炉心
管の外周に位置する炉体と、透明石英ガラス製の中心部
と該中心部の外周の不透明石英ガラス製の外層部によっ
て構成される母材把持部からなることを特徴とする。
【０００９】
【作用】母材把持部の透明石英ガラスの軟化、すなわち
透明石英ガラスの温度上昇は、炉体内の発熱体から生じ
る赤外線によるものである。該透明石英ガラスは赤外線
を全て透過してしまうため、比較的短時間の内に透明石
英ガラスの中心部にまで一様に赤外線が到達し、透明石
英ガラスの粘度が下がって軟化する。したがって、母材
把持部を構成する透明石英ガラスの外側に赤外線を散乱
・反射させる層を設けて、該透明石英ガラスの中心部に
到達する赤外線の量を減らせば、該透明石英ガラスの温
度上昇を押さえることができる。
【００１０】母材把持部の透明石英ガラスの温度上昇を
押さえることができれば、母材把持部の粘度低下は生じ
るものの、母材把持部の変形には至らない。したがっ
て、容易に光ファイバ用多孔質母材の位置を制御するこ
とができるため、精度良く脱水・焼結処理を施せ、大型
の光ファイバ用ガラス母材を得ることが可能となる。
【００１１】
【実施例】以下、本発明の実施例を図面を参照して詳細
に説明する。実施例として用いた光ファイバ用多孔質母
材の脱水・焼結炉は図２に示すような構成である。すな
わち、従来のものと同様に、脱水・焼結のための加熱処
理を行う脱水・焼結炉１と脱水・焼結処理を施す光ファ
イバ用多孔質母材７を把持するための母材把持部８から
なる。具体的には、脱水・焼結炉１は、炉心管２と、該
炉心管２の外周に位置し内部に発熱体４を有する炉体３
からなる。前記炉心管２の上部には母材導入口５、下部
には各処理に適した雰囲気ガスを供給する雰囲気ガス供
給口６が設けられている。
【００１２】また、脱水・焼結処理を施す光ファイバ用
多孔質母材７を前記炉心管２内の所定位置に保持するた
めの母材把持部８が、前記脱水・焼結炉１の上方に配置
されている。前記母材把持部８は、図１に示すように透
明石英ガラス製の中心部９と不透明石英ガラス製の外層
部１０で構成されている。さらに具体的には、前記母材
把持部８は外径45mm、長さ30mmの円柱形状の上部と外径
35mm、長さ 100mmの円柱形状の下部を組み合わせた形を
している。前記中心部の下部は窪みを有する中空部を有
し、光ファイバ用多孔質母材７上部のダミー棒１１を窪
みにかけて把持するようになっている。また、前記中心
部９の外周の外層部１０は厚さ 5mmである。なお、本実
施例で用いた母材把持部８は透明石英ガラス製の中心部
９の外周に多孔質ガラスを堆積させ、He (10l/min)とCl
(0.1l/min)によって構成される雰囲気中、1400℃で30分
間、加熱処理して不透明石英ガラス製の外層部１０を形
成させて製造した。
【００１３】前述したガラス化炉を用いて平衡部の直径
90mm、長さ2000mm、重さ20Kgの光ファイバ用多孔質母材
に表１の条件で脱水・焼結処理を施したところ、何ら問
題が生じることなく光ファイバ用ガラス母材を製造でき
た。また、該光ファイバ用ガラス母材を線引して得た光
ファイバをスクリーニングテストしたが、線引工程並び
にスクリーニングテスト工程とも問題は生じなかった。
さらに、全ての処理終了後に母材把持部について検討し
たが、大きさ・形状共処理開始前と変わらなかった。
【００１４】
【表１】
【００１５】以下、本発明の比較例を図面を参照して詳
細に説明する。比較例として用いた光ファイバ用多孔質
母材の脱水・焼結炉は実施例と同様に図２に示したよう
な構成である。但し、母材把持部８は、透明石英ガラス
のみで構成されており、外径45mm、長さ30mmの円柱形状
の上部と外径35mm、長さ 100mmの円柱状の下部を組み合
わせた形をしている。また下部には光ファイバ用多孔質
母材を把持するための窪みを有した中空部が形成されて
いる。
【００１６】前述したガラス化炉で光ファイバ用多孔質
母材に、実施例と同一の表１に示した条件で、脱水・焼
結処理を施したところ、脱水処理に続く、焼結処理の後
半（焼結開始後４時間位）で母材把持部が軟化変形し、
光ファイバ用多孔質母材が急激に下降してしまった。参
考までに、得られた光ファイバ用ガラス母材を線引した
が、光ファイバ多孔質母材が急激に下降した時に焼結処
理を施されていたと考えられる部分で、光ファイバが断
線してしまった。また、全ての処理終了後に母材把持部
について検討したところ、処理開始前よりも長手方向に
5mm伸び、かつその外径は30mmとなっていることがわか
った。
【００１７】なお、本発明においては、母材把持部の透
明石英ガラスからなる中心部の外側に赤外線を反射・散
乱させる層を設けることが重要である。したがって、母
材把持部の形状や赤外線を反射・散乱させる層である不
透明石英ガラス製の外層部の厚さは、その処理条件によ
って適宜選択すべきものであり、実施例に挙げた例に限
定されるものではない。しかしながら、脱水・焼結処理
時間内の中心部の粘度低下が前記母材把持部の変形に至
らない程度に押さえるよう、すなわちその程度に赤外線
透過量を押さえることが可能である厚さを選択しなくて
はならないことは明らかである。また、その製造方法は
実施例で記載した以外の方法であってもよい。
【００１８】また、本実施例では、大型の光ファイバ用
多孔質母材の脱水・焼結処理の場合のみを取り上げた
が、従来の光ファイバ用多孔質母材の脱水・焼結処理の
場合にも有効である。
【００１９】
【発明の効果】本発明のガラス化炉によれば、近年製造
されるようになった大型の光ファイバ用多孔質ガラス母
材を何ら問題なく脱水・焼結処理し、容易に大型の光フ
ァイバ用ガラス母材を安定して製造することができる。
また、該光ファイバ用ガラス母材を線引して得られる光
ファイバは高品質であり、信頼性がある。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for dehydrating and sintering a porous preform for an optical fiber used for producing a glass preform for an optical fiber. 2. Description of the Related Art Conventionally, a general method for producing a glass preform for an optical fiber is as follows. First, a porous preform for an optical fiber having a desired refractive index distribution and a desired size is synthesized by a VAD method, an external method, or the like. Then, dehydration
Although it is sintering, the common furnace for dehydration and sintering
Dehydration / sintering furnace) is used. Specifically, the porous preform for optical fiber was heated and dehydrated in a furnace with a predetermined atmosphere and temperature, and then the furnace atmosphere and temperature were changed to predetermined conditions suitable for sintering. After that, it is heated and sintered to produce a glass preform for optical fibers. As shown in FIG. 2, an apparatus for dehydrating and sintering a porous preform for an optical fiber includes a dehydrating and sintering furnace 1 for performing a heat treatment for dehydrating and sintering, and a dehydrating and sintering process. It comprises a preform holding portion 8 for holding the porous preform 7 for optical fibers. Specifically, the dewatering / sintering furnace 1 includes a furnace tube 2 and a furnace body 3 which is located on the outer periphery of the furnace tube 2 and has a heating element 4 inside. A base material introduction port 5 is provided at an upper portion of the furnace tube 2, and an atmosphere gas supply port 6 for supplying an atmosphere gas suitable for each process is provided at a lower portion. A preform holding portion 8 for holding a porous preform 7 for an optical fiber to be subjected to dehydration / sintering treatment at a predetermined position in the furnace tube 2 is disposed above the dehydration / sintering furnace 1. ing. [0004] When dewatering together with the porous preform 7 for an optical fiber, the preform holding portion 8 is heated to 1500 ° C. in an atmosphere containing chlorine.
Because it is exposed to severe conditions of 16001600 ° C., it is formed of quartz glass. Further, as the quartz glass, a transparent quartz glass is used because opaque quartz glass has insufficient physical strength. [0005] In recent years, the demand for optical fibers has increased dramatically in the field of communications and the like, and as a result, it is desired to improve productivity. In the current situation, the rate-determining step of optical fiber production is the step of drawing from the optical fiber glass base material to the optical fiber.To improve productivity, shorten the various times related to drawing. is necessary. As one of the methods of shortening the drawing time, there is a method of increasing the size of the glass preform for optical fiber to be drawn and continuously drawing the optical fiber from one glass preform for optical fiber longer than before. .
According to this method, since the length of the optical fiber drawn from one glass preform for optical fiber becomes long, the number of times of changing the glass preform for optical fiber can be reduced, so that various operations accompanying the step change can be performed. It can be omitted, and productivity is improved. In addition, a long-distance optical fiber that does not require fusion splicing or the like can be obtained, and an optical fiber with small transmission loss can be obtained. At present, the enlargement of a porous glass preform for an optical fiber itself, which is a precursor of a glass preform for an optical fiber, which has been quoted, can be achieved by technological advances. However,
The subsequent dehydration and sintering did not go well with the same equipment as before,
It was difficult to obtain a large glass preform for optical fibers. In other words, the dehydration and sintering furnace itself should have been increased in size in accordance with the large optical fiber porous preform.
There is a problem that the preform holding portion, which is simply made larger at the same ratio as the sintering furnace, cannot hold the large-sized porous preform for optical fiber. Specifically, the viscosity of the base material holding portion is reduced, and the shape of the base material is deformed, so that the position of the optical fiber porous base material cannot be accurately controlled,
In some cases, dehydration vitrification cannot be performed with high accuracy, and the preform holding portion may be stretched and cut, and the porous preform for optical fibers may fall. The viscosity of the conventional preform holding portion also decreased when the porous preform for optical fiber was dehydrated and sintered, but the weight of the porous preform for optical fiber was small, so that the preform holding portion was not used. No softening deformation of the part was found. SUMMARY OF THE INVENTION Therefore, an improved preform holding portion for holding a porous preform for optical fibers in a dehydration / sintering furnace, specifically, a large-sized porous preform for optical fibers has been proposed. Dehydration of materials
During the sintering process, there has been an urgent need to improve a preform holding portion capable of holding the optical fiber preform. [0008] In order to solve the above-mentioned problems, the present invention provides a furnace tube, a furnace body having a heating element therein and located on the outer periphery of the furnace tube, and a transparent quartz glass. And a base material gripping portion formed of an opaque quartz glass outer layer around the center portion. The softening of the transparent quartz glass at the base material gripping portion, that is, the temperature rise of the transparent quartz glass, is due to infrared rays generated from the heating element in the furnace. Since the transparent quartz glass transmits all the infrared rays, the infrared rays uniformly reach the center of the transparent quartz glass within a relatively short time, and the viscosity of the transparent quartz glass decreases and softens. Therefore, if a layer that scatters and reflects infrared light is provided outside the transparent quartz glass constituting the base material gripping portion to reduce the amount of infrared light that reaches the center of the transparent quartz glass, the temperature of the transparent quartz glass increases. Can be held down. If the rise in the temperature of the transparent quartz glass in the base material gripping portion can be suppressed, the viscosity of the base material gripping portion decreases, but the base material gripping portion does not deform. Therefore, since the position of the porous preform for optical fiber can be easily controlled, the dewatering / sintering process can be performed with high accuracy, and a large glass preform for optical fiber can be obtained. Embodiments of the present invention will be described below in detail with reference to the drawings. The dewatering and sintering furnace for the porous preform for optical fiber used as an example has a configuration as shown in FIG. That is, as in the conventional case, a dehydration / sintering furnace 1 for performing a heat treatment for dehydration / sintering and a preform holding for holding the optical fiber porous preform 7 to be subjected to the dehydration / sintering treatment. It consists of a part 8. Specifically, the dehydration / sintering furnace 1 includes a furnace tube 2 and a furnace body 3 which is located on the outer periphery of the furnace tube 2 and has a heating element 4 therein.
Consists of A base material introduction port 5 is provided at an upper portion of the furnace tube 2, and an atmosphere gas supply port 6 for supplying an atmosphere gas suitable for each process is provided at a lower portion. A preform holding portion 8 for holding a porous preform 7 for an optical fiber to be subjected to a dehydration / sintering process at a predetermined position in the furnace tube 2 is provided above the dehydration / sintering furnace 1. Are located in As shown in FIG. 1, the base material gripping portion 8 includes a central portion 9 made of transparent quartz glass and an outer layer portion 10 made of opaque quartz glass. More specifically, the base material gripping portion 8 has a cylindrical upper portion having an outer diameter of 45 mm and a length of 30 mm.
The shape is a combination of a cylindrical lower part of 35mm and length of 100mm. The lower part of the center part has a hollow part having a depression, and the dummy rod 11 on the upper part of the optical fiber porous preform 7 is gripped over the depression. The outer layer portion 10 on the outer periphery of the central portion 9 has a thickness of 5 mm. The base material gripping portion 8 used in this embodiment is formed by depositing porous glass on the outer periphery of a center portion 9 made of transparent quartz glass, and He (10 l / min) and Cl
(0.1 l / min) in an atmosphere constituted by opaque quartz glass by heating at 1400 ° C. for 30 minutes. The diameter of the equilibrium section using the above-mentioned vitrification furnace
When a porous preform for an optical fiber having a length of 90 mm, a length of 2000 mm and a weight of 20 kg was subjected to dehydration and sintering treatment under the conditions shown in Table 1, a glass preform for an optical fiber could be produced without any problem. An optical fiber obtained by drawing the glass preform for an optical fiber was subjected to a screening test, but no problems occurred in the drawing step and the screening test step.
Further, after all the processes were completed, the base material gripping portion was examined, but it was not different from that before the start of the size / shape co-processing. [Table 1] Hereinafter, a comparative example of the present invention will be described in detail with reference to the drawings. A furnace for dehydrating and sintering a porous preform for an optical fiber used as a comparative example has a configuration as shown in FIG. However, the base material gripping portion 8 is made of only transparent quartz glass, and is formed by combining a cylindrical upper portion having an outer diameter of 45 mm and a length of 30 mm with a cylindrical lower portion having an outer diameter of 35 mm and a length of 100 mm. ing. Further, a hollow portion having a depression for holding the porous preform for optical fiber is formed in a lower portion. When the porous preform for an optical fiber was subjected to dehydration and sintering treatment in the above-described vitrification furnace under the same conditions as shown in Table 1 as in the embodiment, the sintering treatment following the dehydration treatment was carried out. In the second half (about 4 hours after the start of sintering), the base material gripper softened and deformed.
The porous preform for the optical fiber dropped rapidly. For reference, the obtained optical fiber glass preform was drawn, but the optical fiber was broken at the part where it was considered that the sintering process was performed when the optical fiber porous preform dropped rapidly. Oops. In addition, after examining the base material gripper after all the processes, the longitudinal direction was longer than before the process.
It was found that it was elongated by 5 mm and its outer diameter was 30 mm. In the present invention, it is important to provide a layer that reflects and scatters infrared rays outside the central portion made of transparent quartz glass of the base material holding portion. Therefore, the shape of the base material gripping portion and the thickness of the outer layer made of opaque quartz glass, which is a layer that reflects and scatters infrared rays, should be appropriately selected depending on the processing conditions, and are limited to the examples given in the examples. Not something. However, the thickness is selected so that the decrease in the viscosity of the central portion within the dehydration / sintering treatment time does not lead to the deformation of the base material gripping portion, that is, the thickness capable of suppressing the amount of infrared transmission to that extent. It is clear that it is necessary. Further, the manufacturing method may be a method other than the method described in the embodiment. Further, in this embodiment, only the case of dehydration and sintering of a large-sized porous preform for optical fibers is taken up. It is also effective. According to the vitrification furnace of the present invention, a large-sized porous glass preform for optical fiber, which has been manufactured in recent years, can be subjected to dehydration and sintering without any problem, and the large-sized porous glass can be easily enlarged. Can be stably manufactured.
Further, an optical fiber obtained by drawing the glass base material for an optical fiber has high quality and reliability.
【図面の簡単な説明】
【図１】図１は、本実施例で使用した光ファイバ用多孔
質母材の脱水・焼結装置における母材把持部の断面図で
ある。
【図２】図２は、本実施例ならびに比較例で使用した脱
水・焼結装置の概略図である。
【符号の説明】
１…脱水・焼結炉
２…炉心管
３…炉体
４…発熱体
５…母材導入口
６…雰囲気ガス供給口
７…光ファイバ用多孔質母材
８…母材把持部
９…中心部
１０…外層部BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a preform holding portion in a device for dehydrating and sintering a porous preform for optical fibers used in the present embodiment. FIG. 2 is a schematic diagram of a dewatering / sintering apparatus used in the present example and a comparative example. [Description of Signs] 1 ... Dehydration / sintering furnace 2 ... Furnace tube 3 ... Furnace body 4 ... Heating element 5 ... Base material introduction port 6 ... Atmospheric gas supply port 7 ... Porous base material for optical fiber 8 ... Base material gripping Part 9 ... Center part 10 ... Outer layer part
Claims (1)
孔質母材をつり下げる母材把持部とからなり、前記母材
把持部は透明石英ガラス製の中心部と該中心部の外周の
不透明石英ガラス製の外層部によって構成されているこ
とを特徴とする光ファイバ用多孔質母材の脱水・焼結装
置。(57) [Claims 1] A furnace core tube and a base material holding portion for suspending a porous base material for an optical fiber in the furnace tube, wherein the base material holding portion is made of transparent quartz glass. A dewatering / sintering apparatus for a porous preform for an optical fiber, comprising: a central portion of the optical fiber; and an outer layer made of opaque quartz glass around the central portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11956595A JP3485673B2 (en) | 1995-05-18 | 1995-05-18 | Dehydration and sintering device for porous preform for optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11956595A JP3485673B2 (en) | 1995-05-18 | 1995-05-18 | Dehydration and sintering device for porous preform for optical fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08310828A JPH08310828A (en) | 1996-11-26 |
| JP3485673B2 true JP3485673B2 (en) | 2004-01-13 |
Family
ID=14764486
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11956595A Expired - Lifetime JP3485673B2 (en) | 1995-05-18 | 1995-05-18 | Dehydration and sintering device for porous preform for optical fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3485673B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5380018B2 (en) | 2008-09-03 | 2014-01-08 | 株式会社フジクラ | Optical fiber preform manufacturing method |
-
1995
- 1995-05-18 JP JP11956595A patent/JP3485673B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08310828A (en) | 1996-11-26 |
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