JP2007223824A - Method for sintering porous glass preform - Google Patents

Method for sintering porous glass preform Download PDF

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JP2007223824A
JP2007223824A JP2006044274A JP2006044274A JP2007223824A JP 2007223824 A JP2007223824 A JP 2007223824A JP 2006044274 A JP2006044274 A JP 2006044274A JP 2006044274 A JP2006044274 A JP 2006044274A JP 2007223824 A JP2007223824 A JP 2007223824A
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sintering
base material
porous glass
glass base
preform
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Makoto Yoshida
真 吉田
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Shin Etsu Chemical Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
    • C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
    • 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
    • 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

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  • Engineering & Computer Science (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Life Sciences & Earth Sciences (AREA)
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  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
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  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sintering method for a porous glass preform which enables production of an optical fiber preform with less variation of external diameter after sintering and stable optical characteristics. <P>SOLUTION: The sintering method comprises depositing glass fine particles on the starting member prepared by connecting the dummy rods to both ends of a core rod, and sintering the obtained porous glass preform by running through a vertical sintering furnace, and is characterized in that the sintering temperature at the time when the lower part of a preform passes through the heating region is set higher than that when the upper part passes to sinter the preform by imparting higher heat energy to the lower part. It is preferable to sinter the lower part of the preform at a temperature of 30°C or higher exceeding that of the upper part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、光ファイバの原材となる多孔質ガラス母材を脱水・焼結して透明ガラス化する焼結方法に関する。   The present invention relates to a sintering method in which a porous glass base material used as a raw material of an optical fiber is dehydrated and sintered to form a transparent glass.

従来、光ファイバ母材を製造するために、様々な方法が提案されている。
それらの方法の中でも、両端部にダミーロッドを溶着したコアロッドを出発部材として使用し、これを軸周りに回転させつつその長手方向に沿って、出発部材または複数のバーナを相対的に往復移動させて、出発部材の表面にガラス微粒子を堆積させ、これを電気炉内で脱水・焼結して透明ガラス化する外付け法（ＯＶＤ法）は、比較的任意の屈折率分布のものが得られ、しかも、大口径の光ファイバ母材を量産できることから汎用されている。 Conventionally, various methods have been proposed for manufacturing an optical fiber preform.
Among these methods, a core rod having dummy rods welded to both ends is used as a starting member, and the starting member or a plurality of burners are relatively reciprocated along the longitudinal direction while rotating around this axis. The external method (OVD method) in which glass particles are deposited on the surface of the starting member and then dehydrated and sintered in an electric furnace to form a transparent glass can be obtained with a relatively arbitrary refractive index distribution. Moreover, it is widely used because it can mass-produce large-diameter optical fiber preforms.

ガラス微粒子を堆積させて得られた多孔質ガラス母材は、その後、脱水・焼結して透明ガラス化され、光ファイバ母材とされるが、焼結工程において、屈折率分布の不整や偏芯、曲がりを生ずることがある。これらを防止するために、焼結条件を調整して焼結する方法が提案されている。   The porous glass base material obtained by depositing the glass fine particles is then dehydrated and sintered to form a transparent glass, which is used as an optical fiber base material. May cause wicking or bending. In order to prevent these problems, a method of sintering by adjusting the sintering conditions has been proposed.

特許文献１では、軸方向への熱エネルギーを均一化させて、軸方向の屈折率分布を均一化させる方法が示されている。また、特許文献２では、焼結開始時の最初にガラス化が始まる部分に充分な熱エネルギーを与えることによって、温度分布を均一化させ、偏芯を防ぐ方法が示されている。   Japanese Patent Application Laid-Open No. 2004-151561 discloses a method of making the thermal energy in the axial direction uniform and uniforming the refractive index distribution in the axial direction. Patent Document 2 discloses a method of making temperature distribution uniform and preventing eccentricity by giving sufficient heat energy to a portion where vitrification starts at the beginning of sintering.

通常、多孔質ガラス母材は、鉛直に吊り下げられた状態で焼結されるが、ガラス化時に生じる収縮力によって縮む。このとき母材の下方部は、殆ど自重がかからないで溶融するためその軸方向に縮むが、母材の上方部では、大きな自重が掛かった状態で溶融するため、その軸方向に延伸されながらガラス化する。その結果、母材の上方部では下方部より外径が細くなり、長手方向に外径変動を生じる。   Usually, the porous glass base material is sintered in a state of being suspended vertically, but shrinks due to the shrinkage force generated during vitrification. At this time, the lower part of the base metal melts with almost no self-weight, so it shrinks in the axial direction, but the upper part of the base material melts in a state where a large self-weight is applied. Turn into. As a result, the outer diameter of the upper part of the base material is smaller than that of the lower part, and the outer diameter varies in the longitudinal direction.

従来は、このようにして透明ガラス化された光ファイバ母材を電気炉や旋盤を用いて規定の外径に延伸し、外径調整していたので、焼結後の光ファイバ母材に外径変動が存在しても大きな問題ではなかった。   Conventionally, the optical fiber preform thus formed into a transparent glass has been stretched to a specified outer diameter using an electric furnace or a lathe and adjusted to the outer diameter. The presence of diameter variation was not a big problem.

近年、光ファイバの生産性を向上させて製造コストを低減させるために、電気炉や旋盤による延伸工程を省略し、焼結して得られた光ガラス母材を、そのまま直接光ファイバに線引きする方法が検討されている。
そのためには、軸方向への光学特性が均一であるとともに、その全長にわたって外径変動が抑えられた光ファイバ母材が得られる焼結方法が必要となってきた。
特開平８−２２５３３７号公報 特開２０００−２５６０２０公報 In recent years, in order to improve the productivity of optical fibers and reduce the manufacturing cost, the drawing process by an electric furnace or lathe is omitted, and the optical glass base material obtained by sintering is directly drawn on the optical fiber. A method is being considered.
For this purpose, a sintering method has been required in which an optical fiber preform is obtained in which the optical characteristics in the axial direction are uniform and the fluctuation of the outer diameter is suppressed over the entire length.
JP-A-8-225337 JP 2000-256020 A

本発明は、このような課題を解決するためになされたもので、焼結後の外径変動が小さく、光学特性の安定した光ファイバ母材が得られる多孔質ガラス母材の焼結方法を提供することを目的とする。   The present invention has been made in order to solve such problems, and provides a method for sintering a porous glass preform in which an optical fiber preform having a small outer diameter variation after sintering and having stable optical characteristics is obtained. The purpose is to provide.

請求項１に記載の第１の発明は、コアロッドの両端にダミーロッドを接続してなる出発部材上にガラス微粒子を堆積し、得られた多孔質ガラス母材を縦型焼結炉に通して焼結するに際し、該母材の下方部が該焼結炉の加熱領域を通過するときの焼結温度を該母材の上方部が通過するときよりも高く設定し、該母材の下方部に上方部よりもより大きな熱エネルギーを与えて焼結することを特徴とする多孔質ガラス母材の焼結方法であり、該母材の下方部を上方部よりも３０℃以上高い焼結温度で焼結するのが好ましい。   According to a first aspect of the present invention, glass fine particles are deposited on a starting member formed by connecting dummy rods to both ends of a core rod, and the obtained porous glass base material is passed through a vertical sintering furnace. When sintering, the lower temperature of the base material is set higher than the temperature when the upper part of the base material passes when the lower part of the base material passes through the heating region of the sintering furnace. Is a method for sintering a porous glass base material, which is sintered by applying a larger thermal energy to the upper part, and the lower part of the base material is sintered at a temperature higher by 30 ° C. than the upper part. Is preferably sintered.

請求項３に記載の第２の発明は、コアロッドの両端にダミーロッドを接続してなる出発部材上にガラス微粒子を堆積し、得られた多孔質ガラス母材を縦型焼結炉に通して焼結するに際し、該母材の下方部が該焼結炉の加熱領域を通過するときの焼結速度を該母材の上方部が通過するときよりも遅く設定し、該母材の下方部に上方部よりもより大きな熱エネルギーを与えて焼結することを特徴とする多孔質ガラス母材の焼結方法であり、該母材の下方部を、上方部よりも２０％以上遅い焼結速度で加熱領域を通過させて焼結するのが好ましい。   According to a second aspect of the present invention, glass fine particles are deposited on a starting member formed by connecting dummy rods to both ends of a core rod, and the obtained porous glass base material is passed through a vertical sintering furnace. In sintering, the lower part of the base material is set to be slower than the upper part of the base material when the lower part of the base material passes through the heating region of the sintering furnace. Is a method for sintering a porous glass base material, which is sintered by applying a larger thermal energy to the upper part, and the lower part of the base material is sintered 20% or more slower than the upper part. It is preferred to sinter through the heating zone at a speed.

本発明においては、焼結炉の加熱領域を通過する母材の焼結位置によって、供給するガスの構成比及び供給量を調整すると良く、焼結後の外径が１５０ｍｍφ以上のガラス母材において、その全長で外径変動が±２％に収まるように、焼結温度又は焼結速度を調整するのが好ましい。   In the present invention, the composition ratio and supply amount of the supplied gas may be adjusted depending on the sintering position of the base material that passes through the heating region of the sintering furnace. In a glass base material having an outer diameter of 150 mmφ or more after sintering. It is preferable to adjust the sintering temperature or the sintering speed so that the fluctuation of the outer diameter is within ± 2% over the entire length.

本発明の焼結方法によれば、多孔質ガラス母材の下方部に、上方部よりも充分な熱エネルギーを与えることにより、外径変動を小さく抑えることができ、長手方向に均一な外径を有する光ファイバ母材が得られる。また、外径変動が小さくなるように温度及び速度を調整した場合、長手方向に脱水処理量の変動が発生することがある。その場合、加熱領域を通過する多孔質ガラス母材の部位によって、炉心管内に供給する脱水ガスの構成比及び供給量を変化させて母材の脱水処理量を調整することにより、母材の長手方向への屈折率の変動を低減することができる。   According to the sintering method of the present invention, by giving sufficient heat energy to the lower part of the porous glass base material than the upper part, it is possible to suppress fluctuations in the outer diameter, and to make the outer diameter uniform in the longitudinal direction. An optical fiber preform having the following is obtained. In addition, when the temperature and speed are adjusted so as to reduce the outer diameter variation, the amount of dehydration treatment may vary in the longitudinal direction. In that case, the length of the base material is adjusted by adjusting the dehydration amount of the base material by changing the composition ratio and the supply amount of the dehydrated gas supplied into the core tube depending on the portion of the porous glass base material that passes through the heating region. Variation in refractive index in the direction can be reduced.

以下、本発明の多孔質ガラス母材の焼結方法について、図を用いて詳細に説明する。
図１は、縦型焼結炉の概略を示す縦断面図である。
図において、コアロッド１の両端にダミーロッド２，２’を接続した出発部材上に、ガラス微粒子を堆積した多孔質ガラス母材３が炉心管４内に垂下され、炉心管４には断熱材５とヒータ６が配設されている。
焼結は、多孔質ガラス母材３をヒータ６の設けられた加熱領域を通過させることにより行われる。 Hereinafter, the method for sintering the porous glass preform of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an outline of a vertical sintering furnace.
In the figure, a porous glass base material 3 on which glass fine particles are deposited is suspended in a core tube 4 on a starting member in which dummy rods 2 and 2 ′ are connected to both ends of a core rod 1. And a heater 6 are disposed.
Sintering is performed by passing the porous glass base material 3 through a heating region in which the heater 6 is provided.

炉心管４内に垂下された多孔質ガラス母材３は、駆動源７と焼結速度を増減させる速度制御装置８とに連結され、加熱領域を通過する母材の速度が調整される。炉心管４の下方にはガス導入管９が取り付けられ、脱水反応用ガスである塩素ガスの供給源と、不活性ガスであるヘリウムの供給源（不図示）に接続されている。炉心管４の上方には排気管１０が取り付けられている。   The porous glass base material 3 suspended in the furnace core tube 4 is connected to a drive source 7 and a speed control device 8 for increasing or decreasing the sintering speed, and the speed of the base material passing through the heating region is adjusted. A gas introduction tube 9 is attached below the core tube 4 and is connected to a supply source of chlorine gas that is a dehydration reaction gas and a supply source (not shown) of helium that is an inert gas. An exhaust pipe 10 is attached above the core tube 4.

多孔質ガラス母材の焼結は、以下のようにして実施される。
塩素ガスとヘリウムをそれぞれの供給源からガス導入管９へ流すと、塩素ガスとヘリウムは混合されて炉心管４に導入され、炉心管４内で充満される。ヒータ６により加熱領域が加熱される。多孔質ガラス母材３は、速度制御装置８で駆動が制御されている駆動源７により軸回転しながら、低速で降下しつつ加熱領域を通過する。多孔質ガラス母材３は、加熱により脱水・焼結され、透明ガラス化される。
なお、多孔質ガラス母材をヒータ６より下方に設置して、上昇させながら焼結することもできる。 Sintering of the porous glass base material is performed as follows.
When chlorine gas and helium are allowed to flow from the respective supply sources to the gas introduction tube 9, the chlorine gas and helium are mixed and introduced into the core tube 4, and are filled in the core tube 4. The heating area is heated by the heater 6. The porous glass base material 3 passes through the heating region while descending at a low speed while rotating the shaft by the drive source 7 whose drive is controlled by the speed control device 8. The porous glass base material 3 is dehydrated and sintered by heating to be converted into a transparent glass.
Note that the porous glass base material can be placed below the heater 6 and sintered while being raised.

本発明による焼結方法の特徴は、多孔質ガラス母材の上方部と比較して、下方部に与える熱エネルギーを大きくすることにある。母材の下方部に充分な熱エネルギーを与えることにより、下方部の外径を自重による延伸力によって細めに仕上がる上方部と同程度の外径に収めることができる。上方部に対しては、溶け残りが生じない程度に熱エネルギーを抑制して、軸方向の伸びを抑制する。これにより外径変動を小さく抑えることができ、長手方向に均一な外径を有する母材が得られる。   The feature of the sintering method according to the present invention is that the thermal energy applied to the lower part is increased as compared with the upper part of the porous glass base material. By giving sufficient heat energy to the lower part of the base material, the outer diameter of the lower part can be kept within the same outer diameter as the upper part that is finely finished by the stretching force due to its own weight. For the upper part, the thermal energy is suppressed to such an extent that no undissolved residue is generated, and the axial elongation is suppressed. As a result, fluctuations in the outer diameter can be kept small, and a base material having a uniform outer diameter in the longitudinal direction can be obtained.

焼結時に、多孔質ガラス母材の部位によって与える熱エネルギーを調整するには、母材の下方部ほど焼結温度を高くする方法や、焼結速度を小さくする方法が挙げられ、これらの方法を単独で、あるいは組み合わせて用いても良い。   In order to adjust the thermal energy given by the porous glass base material during sintering, there are a method of increasing the sintering temperature and a method of decreasing the sintering speed in the lower part of the base material. May be used alone or in combination.

なお、外径変動が小さくなるように温度及び速度を調整した場合、長手方向に脱水処理量が変動することがある。その場合、加熱領域を通過する多孔質ガラス母材の部位によって、炉心管内に供給する脱水ガスの構成比及び供給量を変化させることで、母材の脱水処理量を調整することができる。これによって、母材の長手方向への屈折率の変動を低減することができる。
以下、実施例、比較例を挙げて本発明をさらに詳細に説明するが、本発明はこれらに限定されず、様々な態様が可能である。 Note that when the temperature and speed are adjusted so as to reduce the outer diameter variation, the amount of dehydration may vary in the longitudinal direction. In that case, the dehydration amount of the base material can be adjusted by changing the composition ratio and supply amount of the dehydrated gas supplied into the core tube depending on the portion of the porous glass base material that passes through the heating region. Thereby, the fluctuation | variation of the refractive index to the longitudinal direction of a base material can be reduced.
EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited to these, Various aspects are possible.

［実施例１］
外径５０ｍｍφ、長さ２０００ｍｍのコアロッドを用いた出発部材上に、ＯＶＤ法によって外径が３００ｍｍφになるまでガラス微粒子を堆積させて多孔質ガラス母材を形成し、これを図１に示した炉心管内に垂下し、焼結速度１．５ｍｍ／ｍｉｎで降下させ、焼結温度を図２に示すように、母材の下方部での１５５０℃から上方部の１４５０℃へと変化させて焼結した。なお、図２は、縦軸に焼結温度を、横軸に母材の長手方向の位置（長手位置）を示している。なお、比較のために従来法による焼結温度を従来例として併記してある。
得られた光ファイバ母材の外径を測定し、コアロッド径とともに図３に示した。図３は、縦軸にコアロッド径と母材の外径を、横軸に母材の長手方向の位置（長手位置）を示している。
図から、コアロッド径は、全長にわたって５０ｍｍ以下になっていることから、焼結によって光ファイバ母材全体が一様に伸びていることが認められる。その結果、平均母材径が２ｍｍほど細く仕上がったものの、光ファイバ母材の径差は、全長で２．３ｍｍの範囲に収まり、後記した比較例より大きく改善され、このままで光ファイバの線引きに使用することができた。 [Example 1]
On a starting member using a core rod having an outer diameter of 50 mmφ and a length of 2000 mm, a porous glass base material is formed by depositing glass fine particles by an OVD method until the outer diameter becomes 300 mmφ, and this is shown in FIG. It hangs down in the tube, lowers at a sintering speed of 1.5 mm / min, and the sintering temperature is changed from 1550 ° C. in the lower part of the base material to 1450 ° C. in the upper part as shown in FIG. did. FIG. 2 shows the sintering temperature on the vertical axis and the position (longitudinal position) in the longitudinal direction of the base material on the horizontal axis. For comparison, the sintering temperature according to the conventional method is also shown as a conventional example.
The outer diameter of the obtained optical fiber preform was measured and shown in FIG. 3 together with the core rod diameter. FIG. 3 shows the core rod diameter and the outer diameter of the base material on the vertical axis, and the position (longitudinal position) in the longitudinal direction of the base material on the horizontal axis.
From the figure, since the core rod diameter is 50 mm or less over the entire length, it is recognized that the entire optical fiber preform is uniformly extended by sintering. As a result, although the average base material diameter was finished as thin as 2 mm, the difference in diameter of the optical fiber base material was within the range of 2.3 mm in total length, which was greatly improved from the comparative example described later. Could be used.

［実施例２］
実施例１と同じ多孔質ガラス母材を用意し、焼結温度１５００℃で、焼結速度は図４に示すように、母材の下方部での０．９ｍｍ／ｍｉｎから上方部の１．５ｍｍ／ｍｉｎへと変化させて焼結した。なお、図４には、比較のために従来法による焼結速度を従来例として併記してある。
得られた光ファイバ母材の外径を測定し、コアロッド径とともに図５に示した。
図から、コアロッド径は、実施例１と同様に全長にわたって５０ｍｍ以下になっていることから、焼結によって光ファイバ母材全体が一様に伸びていることが認められる。その結果、平均母材径は２ｍｍほど細く仕上がったものの、光ファイバ母材の径差は、全長で２．４ｍｍの範囲に収まり、大きく改善された。
なお、平均母材径が細めに仕上がる点については、コア径と多孔質ガラス母材径をその分予め太くしておくことで、長手方向に外径変動が小さく、所望の径を有する光ファイバ母材が得られる。 [Example 2]
The same porous glass base material as in Example 1 was prepared, the sintering temperature was 1500 ° C., and the sintering speed was 0.9 mm / min in the lower part of the base material as shown in FIG. Sintering was performed at 5 mm / min. In FIG. 4, for comparison, the sintering rate according to the conventional method is also shown as a conventional example.
The outer diameter of the obtained optical fiber preform was measured and shown in FIG. 5 together with the core rod diameter.
From the figure, since the core rod diameter is 50 mm or less over the entire length as in the case of Example 1, it is recognized that the entire optical fiber preform is uniformly extended by sintering. As a result, although the average preform diameter was finished as thin as 2 mm, the difference in diameter of the optical fiber preform was within the range of 2.4 mm in total length, which was greatly improved.
As for the point where the average base material diameter is made narrower, the core diameter and the porous glass base material diameter are increased in advance, so that the outer diameter fluctuation is small in the longitudinal direction and the optical fiber has a desired diameter. A base material is obtained.

［比較例１］
実施例１と同じ多孔質ガラス母材を用意し、焼結速度１．５ｍｍ／ｍｉｎ、焼結温度１５００〔℃〕一定で焼結した。
得られた光ファイバ母材の外径及びコアロッド径は、図６に示す通りである。図からは、コアロッド径が下方部では５０ｍｍよりも太く、上方部では５０ｍｍよりも細くなっていることから、焼結によって光ファイバ母材が伸び縮みしたことが分かる。光ファイバ母材の径差は、全長で１３．２ｍｍにもなり、外径加工が必要で、そのままでは光ファイバの線引きに使用することはできなかった。 [Comparative Example 1]
The same porous glass base material as in Example 1 was prepared, and sintered at a sintering rate of 1.5 mm / min and a sintering temperature of 1500 [° C.].
The outer diameter and core rod diameter of the obtained optical fiber preform are as shown in FIG. From the figure, the core rod diameter is thicker than 50 mm in the lower part and thinner than 50 mm in the upper part, so that it can be seen that the optical fiber preform has expanded and contracted by sintering. The difference in diameter of the optical fiber preform was 13.2 mm in total length, and it was necessary to process the outer diameter, so that it could not be used for drawing an optical fiber as it was.

本発明によれば、光ファイバの製造コスト低減に寄与する。   According to the present invention, it contributes to the reduction of the manufacturing cost of the optical fiber.

本発明による多孔質ガラス母材の焼結に使用した焼結装置の一例を示す概略縦断面図である。It is a schematic longitudinal cross-sectional view which shows an example of the sintering apparatus used for sintering of the porous glass base material by this invention. 実施例１の焼結温度を従来例と比較して示すグラフである。It is a graph which shows the sintering temperature of Example 1 compared with a prior art example. 実施例１の、焼結後の光ファイバ母材の外径及びコアロッド径の分布を示すグラフである。2 is a graph showing the distribution of the outer diameter and core rod diameter of an optical fiber preform after sintering in Example 1. 実施例２の焼結速度を従来例と比較して示すグラフである。It is a graph which shows the sintering speed of Example 2 compared with a prior art example. 実施例２の、焼結後の光ファイバ母材の外径及びコアロッド径の分布を示すグラフである。It is a graph which shows distribution of the outer diameter of the optical fiber preform after sintering of Example 2, and a core rod diameter. 従来法（比較例）による、焼結後の光ファイバ母材の外径及びコアロッド径の分布を示すグラフである。It is a graph which shows distribution of the outer diameter and core rod diameter of the optical fiber preform after sintering by a conventional method (comparative example).

符号の説明Explanation of symbols

１ コアロッド、
２ ダミーロッド、
３ 多孔質ガラス母材、
４ 炉心管、
５ 断熱材、
６ ヒータ、
７ 駆動源、
８ 速度制御装置、
９ ガス導入管、
１０ 排気管。 1 core rod,
2 dummy rod,
3 porous glass base material,
4 Reactor core tube,
5 Insulation,
6 heater,
7 Drive source,
8 Speed control device,
9 Gas inlet pipe,
10 Exhaust pipe.

Claims (6)

コアロッドの両端にダミーロッドを接続してなる出発部材上にガラス微粒子を堆積し、得られた多孔質ガラス母材を縦型焼結炉に通して焼結するに際し、該母材の下方部が該焼結炉の加熱領域を通過するときの焼結温度を該母材の上方部が通過するときよりも高く設定し、該母材の下方部に上方部よりもより大きな熱エネルギーを与えて焼結することを特徴とする多孔質ガラス母材の焼結方法。 When glass particles are deposited on a starting member formed by connecting dummy rods to both ends of the core rod, and the resulting porous glass base material is sintered through a vertical sintering furnace, the lower part of the base material is The sintering temperature when passing through the heating region of the sintering furnace is set higher than when the upper part of the base material passes, and greater thermal energy is given to the lower part of the base material than to the upper part. A method for sintering a porous glass base material, comprising sintering. 該母材の下方部を、上方部よりも３０℃以上高い焼結温度で焼結する請求項１に記載の多孔質ガラス母材の焼結方法。 The method for sintering a porous glass base material according to claim 1, wherein the lower part of the base material is sintered at a sintering temperature higher by 30 ° C or more than the upper part. コアロッドの両端にダミーロッドを接続してなる出発部材上にガラス微粒子を堆積し、得られた多孔質ガラス母材を縦型焼結炉に通して焼結するに際し、該母材の下方部が該焼結炉の加熱領域を通過するときの焼結速度を該母材の上方部が通過するときよりも遅く設定し、該母材の下方部に上方部よりもより大きな熱エネルギーを与えて焼結することを特徴とする多孔質ガラス母材の焼結方法。 When glass particles are deposited on a starting member formed by connecting dummy rods to both ends of the core rod, and the resulting porous glass base material is sintered through a vertical sintering furnace, the lower part of the base material is The sintering speed when passing through the heating zone of the sintering furnace is set slower than when the upper part of the base material passes, and greater thermal energy is given to the lower part of the base material than to the upper part. A method for sintering a porous glass base material, comprising sintering. 該母材の下方部を、上方部よりも２０％以上遅い焼結速度で加熱領域を通過させて焼結する請求項３に記載の多孔質ガラス母材の焼結方法。 The method for sintering a porous glass base material according to claim 3, wherein the lower part of the base material is sintered by passing through the heating region at a sintering rate that is 20% or more slower than that of the upper part. 該焼結炉の加熱領域を通過する該母材の焼結位置によって、供給するガスの構成比及び供給量を調整する請求項１乃至４のいずれかに記載の多孔質ガラス母材の焼結方法。 The sintering of the porous glass base material according to any one of claims 1 to 4, wherein the composition ratio and the supply amount of the supplied gas are adjusted depending on the sintering position of the base material that passes through the heating region of the sintering furnace. Method. 焼結後の外径が１５０ｍｍφ以上のガラス母材において、その全長で外径変動が±２％に収まるように、焼結温度又は焼結速度を調整する請求項１乃至５のいずれかに記載の多孔質ガラス母材の焼結方法。
6. A glass base material having an outer diameter of 150 mm.phi. Or more after sintering, wherein the sintering temperature or the sintering speed is adjusted so that the outer diameter variation is within ± 2% over the entire length. Of sintering a porous glass base material.
JP2006044274A 2006-02-21 2006-02-21 Method for sintering porous glass preform Pending JP2007223824A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109704561A (en) * 2017-02-15 2019-05-03 天津富通集团有限公司 The production technology of large-scale optical fiber prefabricating stick

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109704561A (en) * 2017-02-15 2019-05-03 天津富通集团有限公司 The production technology of large-scale optical fiber prefabricating stick
CN109704561B (en) * 2017-02-15 2021-09-21 天津富通集团有限公司 Production process of large-size optical fiber preform

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