JP2003321238A - Method and apparatus for producing optical fiber preform - Google Patents
Method and apparatus for producing optical fiber preformInfo
- Publication number
- JP2003321238A JP2003321238A JP2002128745A JP2002128745A JP2003321238A JP 2003321238 A JP2003321238 A JP 2003321238A JP 2002128745 A JP2002128745 A JP 2002128745A JP 2002128745 A JP2002128745 A JP 2002128745A JP 2003321238 A JP2003321238 A JP 2003321238A
- Authority
- JP
- Japan
- Prior art keywords
- quartz tube
- optical fiber
- fiber preform
- induction heating
- heating
- 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
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]
- C03B37/018—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] by glass deposition on a glass substrate, e.g. by inside-, modified-, plasma-, or plasma modified- chemical vapour deposition [ICVD, MCVD, PCVD, PMCVD], i.e. by thin layer coating on the inside or outside of a glass tube or on a glass rod
- C03B37/01807—Reactant delivery systems, e.g. reactant deposition burners
- C03B37/01815—Reactant deposition burners or deposition heating means
-
- 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]
- C03B37/018—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] by glass deposition on a glass substrate, e.g. by inside-, modified-, plasma-, or plasma modified- chemical vapour deposition [ICVD, MCVD, PCVD, PMCVD], i.e. by thin layer coating on the inside or outside of a glass tube or on a glass rod
- C03B37/01861—Means for changing or stabilising the diameter or form of tubes or rods
- C03B37/01869—Collapsing
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)
- Manufacture, Treatment Of Glass Fibers (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、光ファイバ母材
の製造方法および装置、さらに詳しく言えば、特にコア
の偏心およびコアの非円不良を排除することを目的とす
る光ファイバ母材の製造方法および装置に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing an optical fiber preform, more specifically, an optical fiber preform intended to eliminate core eccentricity and non-circular defect of the core. A method and apparatus.
【０００２】[0002]
【従来の技術】ＭＣＶＤ法およびＰＣＶＤ法による光フ
ァイバ母材の製造にはコラプス工程が含まれる。コラプ
ス（押し潰し）工程というのは、コアおよびクラッドガ
ラス層の堆積後の石英管を加熱して中実化させることで
ある。2. Description of the Related Art The manufacturing of optical fiber preforms by the MCVD method and the PCVD method includes a collapse process. The collapsing step is heating and solidifying the quartz tube after the core and clad glass layers are deposited.
【０００３】一般的に言ってコラプス工程は、ガラス層
堆積後の石英管をガラスが表面張力によって収縮する程
度の温度で、従来はバーナによって加熱しながらそのバ
ーナを石英管の軸線方向に往復移動させ、石英管をコア
およびクラッド層と共に中実化して光ファイバ母材を形
成するようにするものであり、使用するバーナは下部お
よび斜め横方向から当該石英管のほぼ中心に向かって、
Ｈ2およびＯ2などの燃焼用ガスを噴射するものが普通で
ある。Generally speaking, the collapse process is a temperature at which the quartz tube after the glass layer is deposited is contracted by the surface tension of the glass layer. Conventionally, the burner is reciprocated in the axial direction of the quartz tube while being heated by the burner. In order to form the optical fiber preform by solidifying the quartz tube together with the core and the clad layer, the burner to be used is from the lower part and the oblique lateral direction toward the approximate center of the quartz tube.
It is common to inject combustion gases such as H 2 and O 2 .
【０００４】上述のように使用するバーナの噴射方向は
下部および斜め横方向が普通であるが、これは上方から
の噴射は火炎が上に上がり気味になって熱が十分石英管
に伝わらないこと、また上下、真横同士のような対向関
係にあるバーナの場合は、石英管を外れた部分では互い
に相手バーナを焼き壊すなどの不都合があるからであ
る。As described above, the burner used is generally in the lower and oblique lateral directions. This is because the flame from the upper part of the burner rises upward and the heat is not sufficiently transmitted to the quartz tube. This is because, in the case of the burners that are in an opposing relationship such as vertically and horizontally, there is a problem that the mating burners are burned to each other at the portion outside the quartz tube.
【０００５】[0005]
【発明が解決しようとする課題】以上のように従来一般
的に使用されるバーナの場合は、噴射されるガスによる
圧力が下方からのものに偏ってしまい、このためコラプ
ス工程中に石英管が長手方向に曲がり、この結果完成し
た光ファイバ母材が長手方向に曲がる原因になってしま
う欠点がある。As described above, in the case of the burner generally used in the past, the pressure of the injected gas is biased toward the lower side, so that the quartz tube is not removed during the collapse process. There is a drawback that it bends in the longitudinal direction, and as a result, the completed optical fiber preform bends in the longitudinal direction.
【０００６】さらに、コラプス時の石英管の収縮速度が
通常の光ファイバ母材より遅い光ファイバ母材を作製す
る場合は、より多くの火力が必要になり、このためバー
ナ１０１の火力を上げるとバーナ圧力も同時に上昇し、
結果として上記欠点がさらに拡大されて図２に示すよう
な曲がった光ファイバ母材が生じ、曲がり矯正という余
分な工程を強いられる欠点もある。Further, when producing an optical fiber preform in which the contraction speed of the quartz tube at the time of collapse is slower than that of a normal optical fiber preform, more heating power is required. Therefore, if the burning power of the burner 101 is increased. Burner pressure also rises at the same time,
As a result, the above-mentioned defects are further magnified to form a bent optical fiber preform as shown in FIG. 2, and there is a defect that an extra step of correcting the bend is forced.
【０００７】また図３に示すように、圧力が下方からの
ものに偏るこのバーナ１０１によるときは、別に中実化
の過程で石英管が断面円形のまま収縮できずに断面形が
非円化するおそれがある。これはバーナ１０１の火炎が
下方からのものに偏っているために、石英管１が回転し
て上方にきた部分は加熱されずに放熱し、このため溶融
ガラスの表面張力が石英管の円周方向について均一とな
らずに断面が非円化するものである。この種の光ファイ
バ母材からは良好な偏波分散を有する光ファイバを得る
ことは困難である。Further, as shown in FIG. 3, when the burner 101 in which the pressure is biased from the lower side, the quartz tube cannot be shrunk with the circular cross section in the solidification process and the cross section becomes non-circular. May occur. This is because the flame of the burner 101 is biased to the one from the lower side, so that the portion where the quartz tube 1 rotates and goes up is radiated without being heated, and therefore the surface tension of the molten glass causes the circumferential tension of the quartz tube to rise. The cross section becomes non-circular without being uniform in the direction. It is difficult to obtain an optical fiber having good polarization dispersion from this type of optical fiber preform.
【０００８】さらにコラプス工程では、バーナ１０１の
火炎によって石英管表面がファィアポリッシュ（火炎に
よる研磨）されてしまい、表面から実質的にガラス質が
消失し、この量はときとしてデポジション前の石英管の
体積の実に５０％に達することもある。Further, in the collapse process, the surface of the quartz tube is fire-polished (polished by the flame) due to the flame of the burner 101, and the vitreous substance is substantially lost from the surface. This amount is sometimes the quartz tube before deposition. It can reach up to 50% of the volume.
【０００９】石英管の長手方向の曲がり現象とこのファ
ィアポリッシュが同時に生起したときはさらに重大な不
都合が起きる。再び図３を参照してこれを説明する。石
英管１が曲がっているときは回転の中心軸線が長手方向
の部分部分で図３に示すように偏心することになり、回
転の角度的位置によっては実線に示すようにバーナに近
接した位置をとり、また破線に示すようにバーナから遠
ざかる位置をとる。A more serious disadvantage occurs when the longitudinal bending phenomenon of the quartz tube and the fire polish occur simultaneously. This will be described with reference to FIG. 3 again. When the quartz tube 1 is bent, the central axis of rotation is eccentric as shown in FIG. 3 in the longitudinal part, and depending on the angular position of rotation, the position close to the burner may be changed as shown by the solid line. Also, take a position away from the burner as shown by the broken line.
【００１０】このためバーナから受ける圧力と熱量に大
差が生じ、ファィアポリッシュ量に大差が生じて、光フ
ァイバ母材全体としての中心軸線と内部のデポジション
層の中心軸線とがずれ、光ファイバの偏心の原因になっ
てしまう。For this reason, a large difference occurs in the pressure and heat quantity received from the burner, and a large difference in the amount of fire polish, and the central axis of the optical fiber preform as a whole deviates from the central axis of the internal deposition layer, and the optical fiber It causes eccentricity.
【００１１】またバーナを使用して加熱するコラプス工
程一般について言えば、加熱源であるバーナ周辺は大気
開放されており、このため石英管に与えた熱は大気中に
放散しやすく、それだけ石英管の内部への熱伝達が十分
でなくなると言うことができる。As for the collapse process in which a burner is used for heating, the burner, which is a heating source, is open to the atmosphere. Therefore, the heat applied to the quartz tube is easily dissipated into the atmosphere, and thus the quartz tube is used. It can be said that the heat transfer to the inside of is not sufficient.
【００１２】石英管の内壁に堆積させたコアおよびクラ
ッドガラス層のうち、中心に近い層（つまりコアに相当
する層）の、温度に対するガラス粘度の大きさはコラプ
ス工程の速度を決める大きな要因になるのであるが、ガ
ラスは温度が高くなるほどガラス粘度が下がる傾向にあ
り、しかして温度に対するガラス粘度変化量はドーパン
トの種類によって異なる。Of the core and clad glass layers deposited on the inner wall of the quartz tube, the magnitude of the glass viscosity with respect to temperature of the layer near the center (that is, the layer corresponding to the core) is a major factor that determines the speed of the collapse process. However, the glass tends to have a lower glass viscosity as the temperature rises, and thus the amount of change in the glass viscosity with respect to temperature varies depending on the type of dopant.
【００１３】ガラス粘度を下げるようなドーパント
（例：ＧｅＯ2、Ｂ2Ｏ3、Ｐ2Ｏ5、Ａｌ2Ｏ3など）を石
英管の中心に近い層において多く含む場合、熱伝達が不
十分な従来のコラプス工程であっても満足できるコラプ
ス工程速度を達成できる。しかしながら上記層の大部分
がＳｉＯ2であってほとんどドーパントを含まない場合
や、ガラス粘度を逆に上げるドーパント（例：Ｃｏな
ど）を含む場合は、従来のコラプス工程では熱伝達が不
十分であるために中心に近い層のガラス粘度が高いまま
であり、コラプス工程の速度が非常に遅くなってしまう
欠点がある。When a large amount of a dopant (eg, GeO 2 , B 2 O 3 , P 2 O 5 , Al 2 O 3 etc.) that lowers the glass viscosity is contained in the layer near the center of the quartz tube, the heat transfer is insufficient. Even a conventional collapse process can achieve a satisfactory collapse process speed. However, if most of the above layers are SiO 2 and contain almost no dopant, or if they contain a dopant that increases the glass viscosity in reverse (eg, Co, etc.), heat transfer is insufficient in the conventional collapse process. Therefore, the glass viscosity of the layer close to the center remains high, and the collapse process speed becomes very slow.
【００１４】この場合のコラプス工程速度を速めるため
の改善策としては石英管内部の温度を高めなければなら
ないが、このためにはバーナの火力を上げる必要があ
る。バーナの火力を上げると、これまでに詳しく説明し
たように曲がりが生じやすくなったり、ファィアポリッ
シュ量の増大を起こし、これまた結果として光ファイバ
偏心の原因となる。In order to improve the collapse process speed in this case, the temperature inside the quartz tube must be raised, but for this purpose, it is necessary to increase the burner heat power. When the burning power of the burner is increased, as described in detail above, bending is likely to occur and the amount of fire polish is increased, which also causes optical fiber eccentricity.
【００１５】以上〔０００５〕から〔００１３〕まで詳
しく説明してきたように、酸水素炎のバーナ使用の場合
は不可避的に光ファイバ母材の長手方向の曲がり、断面
の非円化、コア部の偏心などの不都合が避けられず、こ
れらの不都合はコラプス工程の速度を上げるために火力
を上げるときこれに連れて増大するという厄介な欠点で
あった。As described above in detail from [0005] to [0013], when an oxyhydrogen flame burner is used, the optical fiber preform inevitably bends in the longitudinal direction, has a non-circular cross section, and has a core portion. Inconveniences such as eccentricity are unavoidable, and these inconveniences have been the troublesome drawbacks that increase with the increase in heating power in order to increase the speed of the collapse process.
【００１６】[0016]
【課題を解決するための手段】この発明は上述の課題を
解決するためになされたものであって、請求項１の発明
によるその解決手段は、石英管をその中心軸線の周りに
回転させながら、該管内に原材料ガスを供給しつつこれ
を外側から加熱して前記石英管内にガラスを堆積させる
デポジション工程と、前記デポジション工程の後に前記
石英管を加熱し中実化させて光ファイバ母材を得るコラ
プス工程とを有し、前記各加熱工程における石英管の加
熱を、該石英管を誘導加熱炉内に置いて誘導加熱するこ
とによって実施することを特徴とする光ファイバ母材の
製造方法である。The present invention has been made in order to solve the above-mentioned problems, and the means for solving the problems according to the invention of claim 1 is to rotate a quartz tube around its central axis. A deposition step of supplying a raw material gas into the tube and heating it from the outside to deposit glass in the quartz tube; and heating the quartz tube after the deposition step to solidify the optical fiber mother tube. And a collapse step for obtaining a material, wherein the heating of the quartz tube in each heating step is performed by placing the quartz tube in an induction heating furnace and performing induction heating. Is the way.
【００１７】請求項２の発明によるその解決手段は、光
ファィバ母材を製造するときデポジション工程の完了し
た石英管を加熱し中実化させるコラプス工程において、
前記石英管の加熱を、該石英管を誘導加熱炉内に置いて
誘導加熱することによって実施することを特徴とする光
ファィバ母材の製造方法である。According to a second aspect of the present invention, the solution means is a collapse process for heating and solidifying a quartz tube which has been subjected to a deposition process when manufacturing an optical fiber preform,
In the method for producing an optical fiber preform, the quartz tube is heated by placing the quartz tube in an induction heating furnace and performing induction heating.
【００１８】請求項３の発明によるその解決手段は、加
熱すべき石英管の外側に同軸的に設けられる中空円柱状
の発熱体と、前記発熱体の外側に同軸的に配設される中
空円柱状の断熱層と、前記断熱層の外側に同軸的に配置
される概して中空円柱状の誘導コイルとを含む誘導加熱
炉が、前記石英管の軸線方向に可動に設けられて成る光
ファイバ母材の製造装置である。According to a third aspect of the present invention, there is provided a means for solving the problem, in which a hollow cylindrical heating element is provided coaxially outside a quartz tube to be heated, and a hollow circle is provided coaxially outside the heating element. An optical fiber preform in which an induction heating furnace including a columnar heat insulating layer and a generally hollow columnar induction coil coaxially arranged outside the heat insulating layer is provided movably in the axial direction of the quartz tube. Manufacturing equipment.
【００１９】請求項４の発明によるその解決手段は、前
記発熱体の材質としてジルコニア、マグネシア等の酸化
物を用いるとともに、前記誘導加熱炉内の石英管の外径
を測定する外径測定器が配設され、この外径測定値によ
って前記誘導加熱炉の軸線方向の移動速度、または誘導
加熱炉に供給する電力を制御するようにされた請求項２
記載の光ファイバ母材の製造装置である。According to a fourth aspect of the present invention, there is provided an outer diameter measuring device for measuring the outer diameter of a quartz tube in the induction heating furnace, wherein an oxide such as zirconia or magnesia is used as a material for the heating element. It is arranged so that the moving speed of the induction heating furnace in the axial direction or the electric power supplied to the induction heating furnace is controlled by the measured value of the outer diameter.
It is a manufacturing apparatus of the optical fiber preform described.
【００２０】[0020]
【発明の実施の形態】図１にこの発明の一実施例装置
（簡略図）を示す。図１において、符号１は石英管を示
し、この両端は本体部分を省略して描かれた旋盤の対向
する２つのチャック８Ａ，８Ｂに把持されて自身の中心
軸線の周りに回転駆動される。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an apparatus (simplified view) of an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a quartz tube, both ends of which are gripped by two opposing chucks 8A and 8B of a lathe which is depicted with the main body omitted, and are driven to rotate about its own central axis.
【００２１】石英管１の周囲には中空円柱状の石英チュ
ーブ１２が同軸的に配設され、その長手方向のほぼ中程
に同じく中空円柱状の適宜な誘電体材質の発熱体３が石
英管１と同軸的に取り付けられる。石英チューブ１２お
よび発熱体３の外周側には、適宜厚さの中空円柱状の断
熱層４が設けられる。A hollow cylindrical quartz tube 12 is coaxially arranged around the quartz tube 1, and a hollow cylindrical heat generating element 3 made of a suitable dielectric material is also formed substantially in the middle of the longitudinal direction of the quartz tube 12. It is mounted coaxially with 1. A hollow cylindrical heat insulating layer 4 having an appropriate thickness is provided on the outer peripheral sides of the quartz tube 12 and the heating element 3.
【００２２】誘電体としてはたとえばジルコニア（酸化
ジルコニウム）、マグネシア（酸化マグネシウム）等の
金属酸化物が好ましく、この粒状のものを断熱材として
断熱層４の内部に詰め込んでもいい。The dielectric is preferably a metal oxide such as zirconia (zirconium oxide) or magnesia (magnesium oxide), and the granular material may be packed in the heat insulating layer 4 as a heat insulating material.
【００２３】断熱層４の外側には概して中空円柱状の誘
導コイル２が配設される。また石英管チューブ１２の軸
方向の両端部にはシャッタ板９Ａ，９Ｂが取り付けら
れ、加熱ゾーンからの熱が逃げないようにされる。Outside the heat insulating layer 4, a generally hollow cylindrical induction coil 2 is arranged. Further, shutter plates 9A and 9B are attached to both ends of the quartz tube 12 in the axial direction so that heat from the heating zone does not escape.
【００２４】しかして上述した各要素はすべて適宜のフ
レームにまとめられて一つの誘導加熱炉を形成し、アー
ム１０を介して、石英管１に平行に設けられるトラバー
ス軸７に係合して同軸上を往復動する往復スライダ１１
に固着される。All of the above-mentioned elements are assembled into an appropriate frame to form a single induction heating furnace, which is coaxially engaged with the traverse shaft 7 provided parallel to the quartz tube 1 via the arm 10. Reciprocating slider 11 reciprocating above
Stuck to.
【００２５】なお符号５，６は２組の外径測定器であっ
て、符号Ａのついた側が計測用光線の投光側、符号Ｂの
ついた側が受光側である。石英管１の外径を測定するこ
とによって、デポジション工程の進捗具合や、その後の
コラプス工程の進行状態を知ることができる。また符号
１３は放射温度計である。Numerals 5 and 6 are two sets of outer diameter measuring instruments, the side marked A is the projecting side of the measuring light beam, and the side marked B is the light receiving side. By measuring the outer diameter of the quartz tube 1, the progress of the deposition process and the progress of the subsequent collapse process can be known. Reference numeral 13 is a radiation thermometer.
【００２６】図１に示す装置がいまコラプス工程を稼働
中であれば、上述の外径測定器５，６の測定値によって
往復スライダ１１の移動速度、すなわちトラバース軸７
の回転速度を、またデポジション工程中では同器の外径
測定値や放射温度計１３の測定値によって誘導コイル２
に通電する電力を、いずれもフィードバック制御するの
もよい。If the apparatus shown in FIG. 1 is currently in the collapse process, the moving speed of the reciprocating slider 11, that is, the traverse shaft 7 is measured according to the measured values of the outer diameter measuring instruments 5 and 6.
The rotation speed of the induction coil 2 is measured by the measured value of the outer diameter of the device and the measured value of the radiation thermometer 13 during the deposition process.
It is also possible to perform feedback control on the electric power supplied to each.
【００２７】誘導加熱炉の場合、誘電体の材質を上記の
ように金属酸化物とすることで酸素雰囲気の中でも使用
することができ、したがって従来のカーボン式抵抗炉の
ように不活性ガスによるパージも必要なく、また炭素粉
末の飛散等も起きることもない。In the case of an induction heating furnace, it is possible to use it in an oxygen atmosphere by changing the material of the dielectric material to a metal oxide as described above. Therefore, as in the conventional carbon resistance furnace, purging with an inert gas is performed. Is also unnecessary, and the scattering of carbon powder does not occur.
【００２８】以下の数項で従来のバーナ式装置と、本発
明装置との実際的な差を証明するための作製実験の結果
を示そう。図４は一つの光ファイバ母材を例示したもの
で、これでは外周側から中心に向かって、石英管層Ｓ
１、合成クラッド層Ｓ２（ドーパント濃度大）、合成コ
ア層Ｓ３（ドーパント濃度０％）を有する。母材外周部
の直径ｄ2と合成クラッド層の直径ｄ1との比ｄ2／ｄ1＝
１．５である。The following numerical terms will show the results of fabrication experiments for proving a practical difference between the conventional burner type device and the device of the present invention. FIG. 4 exemplifies one optical fiber preform, in which the quartz tube layer S is moved from the outer peripheral side toward the center.
1. It has a synthetic clad layer S2 (high dopant concentration) and a synthetic core layer S3 (dopant concentration 0%). Ratio of the diameter d 2 of the outer peripheral portion of the base material and the diameter d 1 of the synthetic cladding layer d 2 / d 1 =
It is 1.5.
【００２９】これと同型の光ファイバ母材を従来のバー
ナ式装置と、本発明の装置のそれぞれによって作製した
ものを以下に比較説明する。図５は従来のバーナ式装置
によるものの断面図である。この光ファイバ母材では合
成コア層のドーパント濃度が０％であるためガラス粘度
が比較的高く、従来技術の〔００１２〕で説明したよう
に長手方向の曲がり、偏心を生じやすい。石英管層Ｓ１
の左、右の厚みｂ1、ｂ2も互いに異なってしまい、いわ
ゆる偏心が生じてしまった。左、右の厚みの比はｂ1／
ｂ2＝１．５となった。An optical fiber preform of the same type as that manufactured by the conventional burner type device and the device of the present invention will be compared and described below. FIG. 5 is a sectional view of a conventional burner type device. In this optical fiber preform, since the synthetic core layer has a dopant concentration of 0%, the glass viscosity is relatively high, and as described in [0012] of the prior art, bending in the longitudinal direction and eccentricity are likely to occur. Quartz tube layer S1
The left and right thicknesses b 1 and b 2 also differ from each other, and so-called eccentricity occurs. The thickness ratio of left and right is b 1 /
b 2 = 1.5.
【００３０】また母材の石英管層Ｓ１の断面積は、作製
前の断面積より約５０％も減少しておりファィアポリッ
シュによる損耗量が極めて多いことが窺える。Further, the cross-sectional area of the quartz tube layer S1 as the base material is reduced by about 50% from the cross-sectional area before fabrication, which indicates that the amount of wear due to fire polishing is extremely large.
【００３１】現在、光ファイバの量産化を図るために作
製した光ファイバ母材の外周の直径が２．５倍になる程
度に外付け工程、ジャケット工程などを付加するのが一
般的であるが、この作製した母材にも同様に外付け工程
を追加して、元の外周の直径ｂに対して直径が２．５ｂ
になるように母材径を大型化した後、この光ファイバ母
材から紡糸して光ファイバを作りその偏心量を計ったと
ころおよそ１．６μｍであった。これは一般的に知られ
る偏心量の許容値０．８μｍを大きく超えるものであ
る。At present, it is general to add an external mounting step, a jacketing step, etc. to the extent that the outer diameter of the optical fiber preform produced for mass production of optical fibers becomes 2.5 times. Similarly, an external process is added to the prepared base material so that the diameter is 2.5b with respect to the original outer diameter b.
The diameter of the base material was increased so that the optical fiber preform was spun from the optical fiber base material to make an optical fiber, and the eccentricity thereof was measured to be about 1.6 μm. This greatly exceeds the generally known allowable value of eccentricity of 0.8 μm.
【００３２】一方、同じサイズの光ファイバ母材を本発
明の装置によって作製したものについては、図６にその
断面を示すが、石英管層Ｓ１の左、右の厚みｃ1、ｃ2の
比はほぼ１であった。つまり偏心がないということであ
る。On the other hand, FIG. 6 shows a cross section of an optical fiber preform of the same size produced by the apparatus of the present invention. The ratio of the left and right thicknesses c 1 and c 2 of the quartz tube layer S1 is shown in FIG. Was almost 1. In other words, there is no eccentricity.
【００３３】またこの石英管層Ｓ１の断面積は作製前の
それと殆ど同じであって、従来のバーナ式によるものに
見られたファィアポリッシュ損耗が皆無であったことが
立証できた。さらにこの試作母材をバーナ式のものと同
様に外付けして同じ外径とした上で紡糸した光ファイバ
について偏心量を測定したところ約０．１μｍであっ
て、良好なコア偏心量を持つ光ファイバを得ることがで
きた。Further, the cross-sectional area of this quartz tube layer S1 was almost the same as that before production, and it could be proved that there was no fire polish wear observed in the conventional burner type. Further, the eccentricity of the optical fiber spun after the trial base material was externally attached in the same manner as the burner type and had the same outer diameter was about 0.1 μm, and the good core eccentricity was obtained. An optical fiber could be obtained.
【００３４】[0034]
【発明の効果】請求項１および２の発明によれば、石英
管はデポジション工程においてもコラプス工程において
も外周部が一様に、かつガス噴射による圧力を全くうけ
ることなく加熱されるので、長手方向の曲がりもなく、
コア偏心もなく、また全体として非円化することもなく
良好な光ファイバ母材を製造でき、この結果この母材か
ら偏心量の極めて小さい良好な光ファイバを生産できる
効果がある。According to the first and second aspects of the present invention, the quartz tube is heated uniformly in the outer peripheral portion both in the deposition step and the collapse step and without being subjected to any pressure due to the gas injection. There is no bending in the longitudinal direction,
It is possible to manufacture a good optical fiber preform without core eccentricity and without making it non-circular as a whole, and as a result, it is possible to produce a good optical fiber with an extremely small amount of eccentricity from this preform.
【００３５】また請求項３の発明によれば、誘導加熱炉
内が酸化環境であっても構わないから不活性ガスによる
パージ操作の必要がなく、また自動制御がしやすいため
に作業管理者による人力制御の必要が大幅に削減される
利点もある。According to the third aspect of the present invention, since the inside of the induction heating furnace may be in an oxidizing environment, it is not necessary to carry out a purging operation with an inert gas, and since automatic control is easy, the work manager can It also has the advantage of significantly reducing the need for human power control.
【図１】本発明の一実施例装置を示す簡略側断面図であ
る。FIG. 1 is a simplified side sectional view showing an apparatus according to an embodiment of the present invention.
【図２】石英管の曲がりを説明す簡略側面図である。FIG. 2 is a simplified side view illustrating bending of a quartz tube.
【図３】光ファイバ母材がバーナ火炎から受ける熱およ
び圧力の偏在を説明する簡略横断面図である。FIG. 3 is a schematic cross-sectional view for explaining uneven distribution of heat and pressure that an optical fiber preform receives from a burner flame.
【図４】比較実験作製した光ファイバ母材を示す断面図
である。FIG. 4 is a sectional view showing an optical fiber preform produced in a comparative experiment.
【図５】従来のバーナ方式装置によって作製した光ファ
イバ母材を示す断面図である。FIG. 5 is a cross-sectional view showing an optical fiber preform manufactured by a conventional burner system device.
【図６】本発明の装置によって作製した光ファイバ母材
を示す断面図である。FIG. 6 is a cross-sectional view showing an optical fiber preform manufactured by the apparatus of the present invention.
１ 石英管 １０１ バーナ ２ 誘導コイル ３ 発熱体 ４ 断熱層 ５Ａ，６Ａ 外径測定器の投光側 ５Ｂ，６Ｂ 同受光側 ７ トラバース軸 ８Ａ，８Ｂ チャック ９Ａ，９Ｂ シャッタ １０ アーム １１ 往復スライダ １２ 石英チューブ １３ 放射温度計 Ｓ１ 石英管層 Ｓ２ 合成クラッド層 Ｓ３ 合成コア層 1 quartz tube 101 burner 2 induction coil 3 heating element 4 heat insulation layer Light emitting side of 5A, 6A outer diameter measuring instrument 5B, 6B Same light receiving side 7 Traverse axis 8A, 8B chuck 9A, 9B shutter 10 arms 11 reciprocating slider 12 Quartz tube 13 Radiation thermometer S1 quartz tube layer S2 synthetic clad layer S3 synthetic core layer
Claims (4)
転させながら、該管内に原材料ガスを供給しつつこれを
外側から加熱して前記石英管内にガラスを堆積させるデ
ポジション工程と、前記デポジション工程の後に前記石
英管（１）を加熱し中実化させて光ファイバ母材を得る
コラプス工程とを有し、前記各加熱工程における石英管
（１）の加熱を、該石英管（１）を誘導加熱炉内に置い
て誘導加熱することによって実施することを特徴とする
光ファイバ母材の製造方法。1. A deposition step of rotating a quartz tube (1) around its central axis while supplying a raw material gas into the tube and heating it from the outside to deposit glass in the quartz tube. After the deposition step, there is a collapse step of heating and solidifying the quartz tube (1) to obtain an optical fiber preform, and heating the quartz tube (1) in each heating step is performed by the quartz tube (1). A method for producing an optical fiber preform, which is carried out by placing (1) in an induction heating furnace and performing induction heating.
ョン工程の完了した石英管（１）を加熱し中実化させる
コラプス工程において、前記石英管（１）の加熱を、該
石英管（１）を誘導加熱炉内に置いて誘導加熱すること
によって実施することを特徴とする光ファィバ母材の製
造方法。2. The quartz tube (1) is heated in a collapse process for heating and solidifying the quartz tube (1) which has been subjected to a deposition step when manufacturing an optical fiber preform. ) Is placed in an induction heating furnace to perform induction heating, and a method for producing an optical fiber preform.
に設けられる中空円柱状の発熱体（３）と、前記発熱体
（３）の外側に同軸的に配設される中空円柱状の断熱層
（４）と、前記断熱層（４）の外側に同軸的に配置され
る概して中空円柱状の誘導コイル（２）とを含む誘導加
熱炉が、前記石英管（１）の軸線方向に可動に設けられ
て成る光ファイバ母材の製造装置。3. A hollow cylindrical heating element (3) coaxially provided outside the quartz tube (1) to be heated, and a hollow circle coaxially disposed outside the heating element (3). An induction heating furnace including a columnar heat-insulating layer (4) and a generally hollow cylindrical induction coil (2) coaxially arranged outside the heat-insulating layer (4) is an axis of the quartz tube (1). A device for manufacturing an optical fiber preform, which is provided so as to be movable in any direction.
ア、マグネシア等の酸化物を用いるとともに、前記誘導
加熱炉内の石英管（１）の外径を測定する外径測定器
（５Ａ，５Ｂ；６Ａ，６Ｂ）が配設され、この外径測定
値によって前記誘導加熱炉の軸線方向の移動速度、また
は誘導加熱炉に供給する電力を制御するようにされた請
求項２記載の光ファイバ母材の製造装置。4. An outer diameter measuring instrument (5A, 5B) for measuring the outer diameter of a quartz tube (1) in the induction heating furnace, using an oxide such as zirconia or magnesia as a material of the heating element (3). 6A, 6B) are provided, and the moving speed in the axial direction of the induction heating furnace or the electric power supplied to the induction heating furnace is controlled by the measured value of the outer diameter. Material manufacturing equipment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002128745A JP2003321238A (en) | 2002-04-30 | 2002-04-30 | Method and apparatus for producing optical fiber preform |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002128745A JP2003321238A (en) | 2002-04-30 | 2002-04-30 | Method and apparatus for producing optical fiber preform |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2003321238A true JP2003321238A (en) | 2003-11-11 |
Family
ID=29542395
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002128745A Pending JP2003321238A (en) | 2002-04-30 | 2002-04-30 | Method and apparatus for producing optical fiber preform |
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| Country | Link |
|---|---|
| JP (1) | JP2003321238A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7637125B2 (en) | 2003-11-20 | 2009-12-29 | Sumitomo Electric Industries, Ltd. | Glass tube processing method, apparatus and glass tube |
| CN108298810A (en) * | 2018-03-14 | 2018-07-20 | 长飞光纤光缆股份有限公司 | A kind of PCVD precipitation equipments |
| CN109133608A (en) * | 2018-11-16 | 2019-01-04 | 长飞光纤光缆股份有限公司 | A kind of implantation equipment for preform |
-
2002
- 2002-04-30 JP JP2002128745A patent/JP2003321238A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7637125B2 (en) | 2003-11-20 | 2009-12-29 | Sumitomo Electric Industries, Ltd. | Glass tube processing method, apparatus and glass tube |
| US8015845B2 (en) | 2003-11-20 | 2011-09-13 | Sumitomo Electric Industries, Ltd. | Glass tube processing method |
| US8024945B2 (en) | 2003-11-20 | 2011-09-27 | Sumitomo Electric Industries, Ltd. | Glass tube processing apparatus |
| CN108298810A (en) * | 2018-03-14 | 2018-07-20 | 长飞光纤光缆股份有限公司 | A kind of PCVD precipitation equipments |
| CN109133608A (en) * | 2018-11-16 | 2019-01-04 | 长飞光纤光缆股份有限公司 | A kind of implantation equipment for preform |
| CN109133608B (en) * | 2018-11-16 | 2022-02-01 | 长飞光纤光缆股份有限公司 | Doping equipment for optical fiber preform |
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