JPS63225546A - Production of base material for optical fiber - Google Patents

Production of base material for optical fiber

Info

Publication number
JPS63225546A
JPS63225546A JP5899287A JP5899287A JPS63225546A JP S63225546 A JPS63225546 A JP S63225546A JP 5899287 A JP5899287 A JP 5899287A JP 5899287 A JP5899287 A JP 5899287A JP S63225546 A JPS63225546 A JP S63225546A
Authority
JP
Japan
Prior art keywords
core
base material
cladding
porous
porous base
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.)
Pending
Application number
JP5899287A
Other languages
Japanese (ja)
Inventor
Hiroshi Yokota
弘 横田
Toshio Danzuka
彈塚 俊雄
Masumi Ito
真澄 伊藤
Masahiro Takagi
政浩 高城
Hiroo Kanamori
弘雄 金森
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Electric Industries Ltd
Original Assignee
Sumitomo Electric Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sumitomo Electric Industries Ltd filed Critical Sumitomo Electric Industries Ltd
Priority to JP5899287A priority Critical patent/JPS63225546A/en
Publication of JPS63225546A publication Critical patent/JPS63225546A/en
Pending legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03BMANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01Manufacture of glass fibres or filaments
    • C03B37/012Manufacture of preforms for drawing fibres or filaments
    • C03B37/014Manufacture 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]

Abstract

PURPOSE:To produce the titled base material in which migration of OH group into a core is reduced and transmission characteristics are excellent, by depositing fine glass particles for cladding to the outer circumferential part of the porous base material for the core raised bulk density by heating. CONSTITUTION:A raw material (e.g. SiCl4) for forming glass, combustion gas such as H2 and O2 and inert gas such as Ar are fed to burner 1 for synthesizing fine glass particles and subjected to flame hydrolysis reaction to obtain fine glass particles and a porous base material 3 for a core is obtained by depositing the obtained fine glass particles on a starting rod 2 fitted to rotary pulling-up device 4. Then a starting material 5 is obtained by heating this base material 3 at 1,200-1,500 deg.C under the inert gas atmosphere and raising mean bulk density rho(g/cm<3>) to 0.4<=rho<=1.0. Thereafter a composite porous base material consisting of the starting material 5 and a porous body 7 for cladding is formed by fitting this starting material 5 to the rotary pulling-up device 4 without performing vitrification treatment, stretching and flame polishing and depositing fine glass particles for cladding in the axial direction to the outer peripheral part of the starting material 5 from a burner 6 for cladding.

Description

【発明の詳細な説明】 〔産業上の利用分野] 本発明は気相合成法による光ファイバ用母材の製造方法
の改良に関するものである。
DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improvement in a method for manufacturing an optical fiber base material by a vapor phase synthesis method.

〔従来の技術〕[Conventional technology]

気相合成法により光ファイバ用母材を製造する方法とし
て、従来V A D (VaporphaseAxia
l Deposition 気相軸付け)法が知られて
いる。この方法は第1図に示すように、ガラス微粒子合
成用バーナ(以下バーナと略する)1にガラス形成原料
ガスを、HR*o雪等の燃焼ガス及びムr等の不活性ガ
スと共に供給する。ガラス原料としては一般的Ka1a
t4が用いられ、また屈折率を調整するために例えばG
e+0A4sB i F、等の添加剤原料を混合しても
よい。燃焼ガスとしては例えばOH4*  asils
 #  OMEN等の炭化水素系ガスや00等を用いる
こともできる。
Conventionally, V A D (Vaporphase Axia
1 Deposition (vapor phase axis deposition) method is known. In this method, as shown in Fig. 1, a glass forming raw material gas is supplied to a glass particle synthesis burner (hereinafter abbreviated as burner) 1 together with a combustion gas such as HR*o snow and an inert gas such as Mr. . Ka1a is a common glass raw material.
t4 is used and also for example G to adjust the refractive index.
Additive materials such as e+0A4sB i F may be mixed. Examples of combustion gas include OH4* asils
# Hydrocarbon gas such as OMEN, 00, etc. can also be used.

バーナ1の火炎(H,及びolを用いた場合は酸水素炎
)中で該ガラス形成原料ガスは火炎加水分解反応して、
ガラス微粒子を生成する。このガラス微粒子を回転引上
装置4に取りつけた出発棒2の先端部から付着させ始め
、該出発棒2を回転させつつ引き上げてゆくことによシ
、多孔質母材3を出発棒2の軸方向に形成してゆく。
In the flame of burner 1 (oxyhydrogen flame when H and OL are used), the glass forming raw material gas undergoes a flame hydrolysis reaction,
Generates glass particles. The glass particles begin to adhere to the tip of the starting rod 2 attached to the rotary pulling device 4, and by pulling up the starting rod 2 while rotating, the porous base material 3 is moved around the axis of the starting rod 2. Form in the direction.

上記で作製され九多孔質母材3について、次に加熱して
脱水する処理C以下加熱脱水処理とI饗す)及び加熱し
て透明化する処理(以下加熱透明化処理と称す)t−施
こすことにより、透明ガラス母材を得る。該透明ガラス
母材を所定径に延伸してコア用延伸ロッドとした後、第
2図に示すような装置構成において該コア用ロッドを出
発材5として回転引上装置4に装着し、クラッド合成用
バーナ6ft:用いて該コア用ロッドの外周にガラス微
粒子を堆積して、コア用ロッドとクラッド用多孔質体か
らなる複合体を形成する。該複合体を前記したと同様に
加熱脱水処理及び加熱透明化処理して、所望のクラッド
/コア径比を有する光ファイバ用母材を得る。
The nine porous base material 3 produced above is then heated and dehydrated (hereinafter referred to as heat dehydration treatment) and heated to make it transparent (hereinafter referred to as heat transparency treatment) t- By applying this, a transparent glass base material is obtained. After the transparent glass base material is stretched to a predetermined diameter to form a drawn core rod, the core rod is installed as a starting material 5 in a rotary pulling device 4 in the apparatus configuration shown in FIG. 2, and the cladding is synthesized. A 6ft burner is used to deposit glass particles on the outer periphery of the core rod to form a composite consisting of the core rod and the porous cladding body. The composite is subjected to heating dehydration treatment and heating transparentization treatment in the same manner as described above to obtain an optical fiber preform having a desired cladding/core diameter ratio.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

ところで上記した従来法では、コア用透明ガラス母材を
所定径に延伸してコア用ロッドとするが、該コア用ロッ
ドの外周にクラッド用ガラス微粒子を堆積させる前に、
該ロッドの外表面を清浄、平滑にする目的で、火炎研磨
を実施する必要がある。通常この火炎研磨には酸水素炎
が用いられるが、コア用ロッドの表面が火炎に曝される
ため、コア表面に高濃度のOH基が混入してしまう。さ
らに続く工程のクラッド用ガラス微粒子堆積に際しても
、クラッド用バーナの火炎によりコア用aツド外表面は
加熱されるので、これによってもコアにOH基が混入し
てしまう。OH基の存在は光7アイバの重要な特性であ
る伝送損失を著るしく劣化させるので、このOH基混入
は非常(困った問題であつ九。
By the way, in the conventional method described above, the core transparent glass base material is stretched to a predetermined diameter to form the core rod, but before depositing the cladding glass particles on the outer periphery of the core rod,
Flame polishing must be performed to clean and smooth the outer surface of the rod. Usually, an oxyhydrogen flame is used for this flame polishing, but since the surface of the core rod is exposed to the flame, a high concentration of OH groups is mixed into the core surface. In the subsequent process of depositing glass fine particles for the cladding, the outer surface of the core a is heated by the flame of the cladding burner, which also causes OH groups to be mixed into the core. The presence of OH groups significantly deteriorates the transmission loss, which is an important characteristic of optical fibers, so the contamination of OH groups is a very serious problem.

本発明はこの種のガラス原料から気相合成法によシガラ
ス微粒子を形成し、これを堆積して多孔質母材を得て、
これを透明ガラス化して光7アイパ母材を得る方法にお
ける、コアへのOH基混入の問題を解消して、伝送特性
に優れた高品質の光ファイバ用母材を製造できる方法を
提供することを目的とするものである。
The present invention involves forming shiglas fine particles from this type of glass raw material by a vapor phase synthesis method, depositing the same to obtain a porous base material,
To provide a method for manufacturing a high-quality optical fiber base material with excellent transmission characteristics by solving the problem of OH group contamination in the core in a method of obtaining an Optical 7-IPA base material by converting it into transparent glass. The purpose is to

〔問題点を解決するための手段・作用〕本発明はコア相
当部及びクラッド相当部を有する多孔質母材を加熱して
透明化することによシ光ファイバ用母材を製造する方法
において、ガラス原料をバーナ火炎中に供給して気相反
応させることにより生成したガラス微粒子を堆積させて
コア用多孔質母材を形成し、次に該コア用多孔質母材を
加熱することによりかさ密度の上昇したコア用多孔質母
材とした後、該コア用多孔質母材の外周部にクラッド用
ガラス微粒子を堆積させることにより複合多孔質母材を
得ることを特徴とする光7アイパ用母材の製造方法に関
する。
[Means and effects for solving the problems] The present invention provides a method for manufacturing an optical fiber preform by heating and transparentizing a porous preform having a core-equivalent portion and a clad-equivalent portion. A porous base material for the core is formed by depositing glass particles produced by supplying glass raw materials into a burner flame and causing a gas phase reaction, and then heating the porous base material for the core to increase the bulk density. A composite porous base material for Hikari 7 Eyepa is obtained by forming a porous base material for a core having an elevated temperature, and then depositing fine glass particles for cladding on the outer periphery of the porous base material for a core. It relates to a method of manufacturing materials.

本発明の特に好ましい実施態様としては、加熱によシコ
ア用多孔質母材の平均かさ密度ア(f/cIII” )
をa4く;ii;<toとして行なう上記方法が挙げら
れる。
In a particularly preferred embodiment of the present invention, the average bulk density a(f/cIII") of the porous matrix for heating cores is
The above method is carried out as a4;ii;<to.

本発明はコア用多孔質母材を形成して加熱脱水処理を行
うところまでは従来と同様であるが、該脱水処理された
多孔質体を加熱して収縮させ、その平均かさ密度を高め
る。特に好ましくはその平均かさ密度iが、αa <f
i <t oとなるように加熱して収縮させる。このよ
うな加熱は通常電気炉を用いてHe ガス雰囲気下温度
1200゜〜1500℃に保持することによシ行われる
The present invention is the same as the conventional method up to the point where a porous base material for the core is formed and heated and dehydrated, but the dehydrated porous body is heated to shrink and increase its average bulk density. Particularly preferably, the average bulk density i is αa < f
It is heated and contracted so that i < t o. Such heating is normally carried out by using an electric furnace and maintaining the temperature at 1200° to 1500° C. in a He gas atmosphere.

加熱収縮されたコア用多孔質母材を、この状態のままで
、すなわち透明化処理や延伸や火炎研磨なしに、第2図
の構成の引上回転装置4に出発材5として装着して、ク
ラッド用バーナ6を用いて公知の手段によシその外周部
にクラッド用ガラス微粒子を堆積させて軸方向に成長さ
せ、前記コア用多孔質母材(出発材5)とクラッド用多
孔質体7とからなる複合多孔質母材を得る。該複合多孔
質母材について、加熱脱水処理及び加熱透明化処理を行
うことによりコア・クラッドを有する透明ガラス母材を
得、ま九これを線引きすることによシ光ファイバが得ら
れる。
The heat-shrinked porous base material for the core is mounted as a starting material 5 in this state, that is, without any transparent treatment, stretching, or flame polishing, to the pulling and rotating device 4 having the configuration shown in FIG. Fine glass particles for cladding are deposited on the outer periphery of the cladding burner 6 by known means and grown in the axial direction, thereby forming the porous base material for the core (starting material 5) and the porous body 7 for the cladding. Obtain a composite porous base material consisting of. The composite porous preform is subjected to heating dehydration treatment and heating transparentization treatment to obtain a transparent glass preform having a core and cladding, and by drawing this, an optical fiber is obtained.

〔作用] 本発明はコア用多孔質母材についての透明化処理、延伸
及び火炎研磨処理を行わないので、延伸や火炎研磨によ
るOH基の混入がない0従って、従来法のようにコア・
クラッド界面に高濃度のOH基層が形成されることはな
い。
[Function] Since the present invention does not perform transparency treatment, stretching, or flame polishing on the porous base material for the core, there is no contamination of OH groups due to stretching or flame polishing.
A highly concentrated OH base layer is not formed at the cladding interface.

ま念、平均かさ密度iを高め、特に好ましくはiがl1
4く;<toとなるよう加熱収縮されたコア用多孔質母
材は、次の工程でクラッド用ガラス微粒子を堆積させる
際にクラッド用バーナの火炎で加熱されるために、その
外周囲にOH基が*#)込まれるが、クラッド用多孔質
体を形成した後、複合多孔質母材の加熱脱水処理の際に
上記のコア中に取り込まれたOH基を除去される。この
ときコア用多孔質母材の平均かさ密度βが1よ)大であ
るとコア用多孔質母材の外表面のOH基除去が不充分と
な)好ましくない。まfl−7sが14未満ではクラッ
ド用ガラス微粒子を堆積する際に、コア用多孔質母材と
の界面付近でクラックが発生し易くなシ、安定な製造が
困難となるため好ましくない。なお、通常のMAD法等
により作成した多孔質体の平均かさ密度はα2〜α3程
度である。
Carefully, the average bulk density i is increased, particularly preferably when i is l1
4) The porous base material for the core, which has been heat-shrinked so as to become However, after forming the porous body for cladding, the OH groups taken into the core are removed during the heating dehydration treatment of the composite porous base material. At this time, if the average bulk density β of the porous base material for the core is greater than 1, the removal of OH groups from the outer surface of the porous base material for the core will be insufficient. If Mfl-7s is less than 14, cracks are not likely to occur near the interface with the porous base material for the core when depositing glass particles for the cladding, and stable production becomes difficult, which is not preferable. Note that the average bulk density of a porous body created by a normal MAD method or the like is about α2 to α3.

本発明によシ、グレーデッド型ファイバのコア用多孔質
母材の複数について、その平均かさ密度アが種々の値と
なるように加熱収縮した後に、コア・クラッドを有する
複合多孔質母材とし、透明化後線引きして得た7アイパ
の波長1、3811mにおけるOH吸収臣ス増を調べた
According to the present invention, a plurality of porous preforms for the core of a graded fiber are heat-shrinked so that the average bulk density a becomes various values, and then a composite porous preform having a core and cladding is prepared. The increase in OH absorption at the wavelength 1, 3811 m of 7 Aipa obtained by drawing after clearing was investigated.

得られた結果を、加熱収縮後のコア用多孔質母材の平均
かさ密度″P(t/cm” )を横軸に、得られたファ
イバの08吸収ロス増(dB/km )t’縦軸にとっ
て両者の関係を示したグラフとして、第5図に示す。
The obtained results are plotted using the average bulk density "P (t/cm") of the porous base material for the core after heat shrinkage as the horizontal axis, and the 08 absorption loss increase (dB/km) t' of the obtained fiber as the vertical axis. A graph showing the relationship between the two along the axis is shown in FIG.

本発明における、ガラス原料から気相合成したガラス微
粒子を堆積することによる多孔質母材の製造は従来公知
の技術にて行えばよく、例えばWAD法、0VPD法、
プラズマ火炎法等を挙げることができる。
In the present invention, the production of the porous base material by depositing glass fine particles synthesized in a vapor phase from glass raw materials may be performed using conventionally known techniques, such as the WAD method, the 0VPD method,
Examples include plasma flame method.

コア又はクラッド用のガラス原料としては例えは810
4 、 8111O74等を用いることができ、これ等
に屈折率その他を調整するための添加剤として例えばG
 eOt4. 8 Ar4 、  sya t  00
4F1  等を加えることができる。
An example of a glass raw material for the core or cladding is 810.
4, 8111O74, etc. can be used, and additives such as G for adjusting the refractive index etc. can be used.
eOt4. 8 Ar4, sya t 00
4F1 etc. can be added.

燃料ガス及び助燃ガスとしては一般的なHloH,、C
3H・、O冨、  oo  等を用いることができ、不
活性ガスとしてはAr j li雪等を用いることがで
きる。
Common HloH,,C as fuel gas and auxiliary gas
3H., Ofu, oo, etc. can be used, and Ar j li snow etc. can be used as the inert gas.

コア用多孔質母材の加熱脱水処理鉱、例えば電気炉を用
いて通常Be ガスとat、又はOt化合物ガスとの混
合雰囲気下温度800〜1100℃にて加熱するととく
よる。
The porous base material for the core is heated and dehydrated, for example, when it is heated in an electric furnace at a temperature of 800 to 1100° C. in a mixed atmosphere of Be gas and At or Ot compound gas.

加熱脱水処理したコア用多孔質体は次に前記したように
電気炉を用いて通常はHe ガス雰囲気下で温度120
0〜1500℃にて加熱して、カサ密度を上昇させる。
The heated and dehydrated porous body for the core is then heated to a temperature of 120°C in an electric furnace, usually under a He gas atmosphere, as described above.
The bulk density is increased by heating at 0 to 1500°C.

またカサ密度を上昇させたコア用多孔質母材の外周部に
クラッド用ガラス微粒子を堆積させ複合多孔質母材とす
る工程は、上記したコア用多孔質体形成と同様に行なえ
ばよく、該複合多孔質母材の加熱脱水処理、加熱透明化
処理も同様に行なえばよい。
In addition, the step of depositing glass particles for cladding on the outer periphery of the porous base material for the core with increased bulk density to form a composite porous base material may be performed in the same manner as the formation of the porous body for the core described above. The heating dehydration treatment and heating transparentization treatment of the composite porous base material may be performed in the same manner.

〔実施例] 実施例1 第1図に示す装置構成において、コア用バーナKH,2
,35t/分、02717分、ムr4t/分、8104
560 CC7分及びGe0432 CC7分を供給し
て、引き上げ速度59−7時でコア用多孔質体を作製し
た。得られたコア用多孔質体の外径は87■φ、平均が
さ密度はα19f/cm”であった。該コア用多孔質体
を電気炉を用いて、温度1050℃で0116容積%(
ガス分圧比)t−含むHe ガス雰囲気中にて加熱脱水
処理した。次にHe ガスのみの雰囲気として、140
0℃に加熱することにより、咳多孔質母材の平均かさ密
度をα72とした。
[Example] Example 1 In the device configuration shown in FIG.
, 35t/min, 02717min, 4t/min, 8104
A core porous body was produced by supplying 7 minutes of 560 CC and 7 minutes of Ge0432 CC at a pulling rate of 59-7 hours. The outer diameter of the obtained porous body for a core was 87 φ, and the average bulk density was α19f/cm.The porous body for a core was heated to 0.116% by volume (
Gas partial pressure ratio) Heating and dehydration treatment was performed in a t-containing He gas atmosphere. Next, as an atmosphere containing only He gas, 140
By heating to 0°C, the average bulk density of the porous matrix was set to α72.

この加熱収縮したコア用多孔質母材を第2図に示す装置
構成において出発材5とし、その外周にクラッド用多孔
質体を形成した。このときクラッド用バーナにはa、s
et/分、014567分、Ar13z/分、BLOl
、 & 20 t7分を供給し、引上速度は84■/時
とした。
This heat-shrinked porous base material for a core was used as a starting material 5 in the apparatus configuration shown in FIG. 2, and a porous body for a cladding was formed around its outer periphery. At this time, the cladding burner has a, s
et/min, 014567 min, Ar13z/min, BLOl
, &20 t7 minutes were supplied, and the pulling speed was 84 ■/hour.

クラッド用多孔質体部分のかさ密度はα51f/ am
 ’であった。
The bulk density of the porous body part for cladding is α51f/am
'Met.

得られた複合多孔質母材を、電気炉を用いてOL、6容
積係を含むHe ガス雰囲気中にて1060℃で加熱脱
水処理した。次KHIS のみのガス雰囲気として16
20CK加熱して透明ガラス化したところ、得られた透
明ガラス母材のコア・クラッド界面には気泡の発生は見
られなかった。
The obtained composite porous base material was heated and dehydrated at 1060° C. in a He gas atmosphere containing OL and 6 volume fractions using an electric furnace. 16 as a gas atmosphere only for KHIS
When heated for 20 CK to produce transparent glass, no bubbles were observed at the core-clad interface of the resulting transparent glass base material.

該透明ガラス母材を線引きして外径125μm1 屈折
率差194%のグレーデッド型7アイパを作製し、その
光伝送損失を測定したとζろ、波長1.38μmにおけ
るOH吸収ロスは(L S 1 dB/IC1l、波長
LSpmではl 52 dB/ks*と良好な特性を示
した。
A graded 7-eyeper with an outer diameter of 125 μm and a refractive index difference of 194% was fabricated by drawing the transparent glass base material, and its optical transmission loss was measured. It showed good characteristics of 1 dB/IC1l and l52 dB/ks* at the wavelength LSpm.

比較例1 実malにおいて他の条件は同様にしてコア用多孔質母
材を加熱収縮させる温度f:1600℃に上げたところ
、透明ガラス化しな。このロッドを延伸することなく、
その外側に実施例1と同条件でクラッド用ガラス微粒子
を堆積して同様に加熱脱水処理し、次に透明ガラス化処
理を行ったところ、コアとタララドガラスの界面の一部
に気泡の発生した透明ガラス母材が得られた。該母材の
気泡のない部分を線引きして7アイバとし、その伝送ロ
スを測定したところ、波長t 58 am においてO
EI 吸収ロスは五〇dB/kIl、波長t S pm
でt 2 an/kmと実施f111の本発明品に比し
て高す値であシ、伝送特性が劣っていた。
Comparative Example 1 When the temperature f for heating and shrinking the porous base material for the core was raised to 1600° C. under the same conditions except for the actual mold, the material did not become transparent vitrified. Without stretching this rod,
Glass fine particles for cladding were deposited on the outside under the same conditions as in Example 1, heated and dehydrated in the same way, and then transparent vitrified. A glass matrix was obtained. The bubble-free portion of the base material was drawn to form 7 fibers, and the transmission loss was measured.
EI absorption loss is 50 dB/kIl, wavelength t S pm
t 2 an/km, which was a higher value than the product of the present invention tested in f111, and the transmission characteristics were inferior.

実施992 第1図の装置構成(て、コア用バーナにH。Implementation 992 The device configuration shown in Figure 1 (with H for the core burner).

2.8 t/分、O嘗 917分、ムr5A/分及び1
1104550 cc/分を供給して、引上速度80閣
/分で、外径55−φ、平均カサ密度a27のコア用多
孔質体を作製した。該コア用多孔質体を電気炉にて、■
・ 10f/分、O1黛500CC/分の雰囲気下、温
[1050℃にて加熱脱水処理した後、Ife  10
j/分のみの雰囲気とし、1460℃で加熱収縮処理し
て、その平均かさ密度を1924C増加させた。
2.8 t/min, 0.917 min, mur5A/min and 1
A porous body for a core having an outer diameter of 55-φ and an average bulk density of a27 was produced by supplying 1104550 cc/min at a pulling rate of 80 mm/min. The porous body for the core is heated in an electric furnace,
- Ife 10
The sample was subjected to heat shrinkage treatment at 1,460° C. in an atmosphere of only J/min, and its average bulk density was increased by 1,924° C.

該加熱収縮した多孔質体について第2図の装置構成で、
クラッド用バーナにII、aat1分10! 62f/
分、ムr15A/分、B1(3147,4t/分を供給
し、引上速度71−7時で1クラッド用ガラス微粒子体
を堆積させて、外径210■φの複合多孔質体を得た。
With the apparatus configuration shown in FIG. 2 for the heat-shrinked porous body,
II for cladding burner, aat 1 minute 10! 62f/
A composite porous body with an outer diameter of 210 φ was obtained by supplying 15 A/min, B1 (3147.4 t/min) and depositing glass fine particles for 1 cladding at a pulling speed of 71-7 hours. .

この複合多孔質体を電気炉を用いて、at、6容積憾を
含むH・ガス雰囲気下1060℃で加熱脱水処理し、続
いて2.7容積僑の8174 を含むIie ガス雰囲
気下1250℃に加熱して?添加し、次いで2.7容積
憾のB i P、を含むHe雰囲気にて1610℃に加
熱することによシ透明ガラス化した。
This composite porous body was heated and dehydrated at 1060°C in an H gas atmosphere containing 8174 vol. at 1250° C. using an electric furnace. Heat it up? and then heated to 1610° C. in a He atmosphere containing 2.7 volumes of B i P to form transparent vitrification.

得られたガラスロッドを加熱延伸した後、クラッド/コ
ア径比が15となるように再度上記と同様の条件にてク
ラッド用ガラス微粒子を堆積し、上記同様に透明ガラス
化した。
After heating and stretching the obtained glass rod, glass fine particles for cladding were deposited again under the same conditions as above so that the cladding/core diameter ratio was 15, and transparent glass was formed in the same manner as above.

以上で得られた光ファイバ用母材ロッドを線引して外径
125pmの光ファイバとしな。該ファイバは純シリカ
のコアとF(ふっ素)が添加された810雪  クラッ
ドの屈折率差がCL29qbテア;b シングルモード
ファイバであり、カットオフ波長λm 1.17μm1
伝送ロスは波長1.5pmで(L 54 aB/km、
波長1.55 pmでα19dLB/krx、O)!吸
収ロスは波長1.58 pmで[L9eL B/kmと
良好な特性を示した。
The optical fiber base material rod obtained above was drawn to form an optical fiber with an outer diameter of 125 pm. The fiber is a single-mode fiber with a refractive index difference of CL29qb tear;b between a pure silica core and an F (fluorine)-doped 810 cladding, and has a cutoff wavelength λm of 1.17μm1.
The transmission loss is at a wavelength of 1.5 pm (L 54 aB/km,
α19dLB/krx at wavelength 1.55 pm, O)! The absorption loss was [L9eLB/km] at a wavelength of 1.58 pm, showing good characteristics.

比較例2 実施例2において、コア用多孔質体の加熱収縮処理温度
を1630℃に上げて透明ガラス化した以外は、実施例
2におけると同条件にて行って光ファイバ用母材ロッド
を得て、これを線引きしファイバとし友。該ファイバの
OH’吸収ロスは波長1.38μmで294B/laa
と非常に大きくな〕、ま九波長1.5μmでの伝送ロス
も1.1dB/に1mであり、実施例20本発明品に比
して著しく劣化していた。
Comparative Example 2 An optical fiber preform rod was obtained under the same conditions as in Example 2, except that the heat shrinkage treatment temperature of the core porous body was raised to 1630°C to make it transparent vitrified. Then, draw this wire and use it as a fiber. The OH' absorption loss of this fiber is 294B/laa at a wavelength of 1.38μm.
The transmission loss at a wavelength of 1.5 μm was also 1.1 dB/1 m, which was significantly worse than the product of Example 20 of the present invention.

〔発明の効果〕 本発明は、OH基混入の原因となるコア用多孔質体の加
熱延伸、火炎研磨を行なわずに、該多孔質体の平均カサ
密度を上昇せしめるよう加熱収縮した後、この外周にク
ラッド用多孔質体を形成することで、クラッド形成時で
のOH基混入の問題をも解決できる。
[Effects of the Invention] The present invention does not perform heating stretching or flame polishing of the porous body for the core, which may cause the contamination of OH groups, but after heating and shrinking the porous body to increase the average bulk density of the porous body, By forming a porous body for cladding on the outer periphery, it is also possible to solve the problem of OH group contamination during cladding formation.

したがって本発明はO)I吸収ロスが低減されており、
かつ伝送特性に優れた光ファイバを製造できる光ファイ
バ用母材の製造方法として非常に有利である。またコア
用多孔質体の加熱透明化、延伸、火炎研磨といった処理
工程を省略できる点も工程的に有利である。
Therefore, the present invention has reduced O)I absorption loss,
Moreover, it is very advantageous as a method of manufacturing an optical fiber base material that can manufacture an optical fiber with excellent transmission characteristics. Further, it is advantageous in terms of process that processing steps such as heating and transparentizing the porous body for the core, stretching, and flame polishing can be omitted.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は本発明のコア用多孔質体を作製する工程の実施
態様を説明する概略断面図、第2図は本発明のコア用多
孔質体外周にクラッド用多孔質体を形成し複合多孔質を
作製する工程の実施態様を説明する概略断面図、第3図
は加熱収縮されたコア用多孔質母材の平均かさ密度(1
7cm” )と、該母材から得たファイバのOH吸収ロ
ス(dB島)の関係を示すグラフである。 第1図      第2図 平均b)さ密度(%]3)
FIG. 1 is a schematic cross-sectional view illustrating an embodiment of the process of producing a porous body for a core according to the present invention, and FIG. FIG. 3 is a schematic cross-sectional view illustrating an embodiment of the process of producing a core material, and FIG. 3 shows the average bulk density (1
7cm") and the OH absorption loss (dB island) of the fiber obtained from the base material. Fig. 1 Fig. 2 Average density (%) 3)

Claims (2)

【特許請求の範囲】[Claims] (1)コア相当部及びクラッド相当部を有する多孔質母
材を加熱して透明化することにより光ファイバ用母材を
製造する方法において、ガラス原料をバーナ火炎中に供
給して気相反応させることにより生成したガラス微粒子
を堆積させてコア用多孔質母材を形成し、次に該コア用
多孔質母材を加熱することによりかさ密度の上昇したコ
ア用多孔質母材とした後、該コア用多孔質母材の外周部
にクラッド用ガラス微粒子を堆積させることにより複合
多孔質母材を得ることを特徴とする光ファイバ用母材の
製造方法。
(1) In a method of manufacturing an optical fiber preform by heating and making transparent a porous preform having a core-equivalent portion and a clad-equivalent portion, a glass raw material is fed into a burner flame and subjected to a gas phase reaction. The glass fine particles produced by this are deposited to form a porous base material for the core, and then the porous base material for the core is heated to form a porous base material for the core with increased bulk density. 1. A method for producing an optical fiber preform, which comprises obtaining a composite porous preform by depositing glass fine particles for cladding on the outer periphery of a porous preform for a core.
(2)加熱によりコア用多孔質母材の平均かさ密度@ρ
@(g/cm^3)を0.4≦@ρ@≦1.0として行
なう特許請求の範囲第1項に記載される光ファイバ用母
材の製造方法。
(2) Average bulk density of porous base material for core by heating @ρ
A method for manufacturing an optical fiber preform according to claim 1, wherein @(g/cm^3) is set to 0.4≦@ρ≦1.0.
JP5899287A 1987-03-16 1987-03-16 Production of base material for optical fiber Pending JPS63225546A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP5899287A JPS63225546A (en) 1987-03-16 1987-03-16 Production of base material for optical fiber

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5899287A JPS63225546A (en) 1987-03-16 1987-03-16 Production of base material for optical fiber

Publications (1)

Publication Number Publication Date
JPS63225546A true JPS63225546A (en) 1988-09-20

Family

ID=13100340

Family Applications (1)

Application Number Title Priority Date Filing Date
JP5899287A Pending JPS63225546A (en) 1987-03-16 1987-03-16 Production of base material for optical fiber

Country Status (1)

Country Link
JP (1) JPS63225546A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04310531A (en) * 1991-04-03 1992-11-02 Yazaki Corp Production of optical fiber preform
US6904772B2 (en) 2000-12-22 2005-06-14 Corning Incorporated Method of making a glass preform for low water peak optical fiber

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04310531A (en) * 1991-04-03 1992-11-02 Yazaki Corp Production of optical fiber preform
JP2592359B2 (en) * 1991-04-03 1997-03-19 矢崎総業株式会社 Burner control device for forming clad members
US6904772B2 (en) 2000-12-22 2005-06-14 Corning Incorporated Method of making a glass preform for low water peak optical fiber
US6944382B2 (en) 2000-12-22 2005-09-13 Corning Incorporated Low water peak optical waveguide fiber
US7076141B2 (en) 2000-12-22 2006-07-11 Corning Incorporated Low water peak optical waveguide fiber

Similar Documents

Publication Publication Date Title
JP2515728B2 (en) Optical fiber rod preform and fiber manufacturing method
JPH0196039A (en) Production of optical fiber preform
CN102757179B (en) Method for preparing large-size optical fiber preform
JPH0425210B2 (en)
US3933453A (en) Flame hydrolysis mandrel and method of using
JPS63225546A (en) Production of base material for optical fiber
JP2793617B2 (en) Manufacturing method of optical fiber preform
JP2818707B2 (en) Method for producing quartz glass base material
JP3498590B2 (en) Manufacturing method of preform for optical fiber
JPH0426523A (en) Production of optical fiber
JPH01111747A (en) Production of optical fiber preform
JPH0798671B2 (en) Method for manufacturing preform for optical fiber
JPS62191434A (en) Production of parent material for optical fiber
JPH04260630A (en) Production of preform optical fiber
JPS59141436A (en) Manufacture of optical fiber preform
JP2770103B2 (en) Manufacturing method of optical fiber preform
JPH054825A (en) Production of glass article
JPH0327493B2 (en)
JPS63151639A (en) Production of glass preformer for optical fiber
JPS58135147A (en) Preparation of base material for optical fiber
JP3752990B2 (en) Method for producing fluorine-added glass article
JPH0784331B2 (en) Method for manufacturing glass base material for optical fiber
JPS6054936A (en) Manufacture of preform rod
JPH04124044A (en) Production of quartz-based glass preform
JPH02208234A (en) Production of optical fiber preform