JP4203731B2 - Manufacturing method of glass preform for optical fiber - Google Patents

Manufacturing method of glass preform for optical fiber Download PDF

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JP4203731B2
JP4203731B2 JP2003146769A JP2003146769A JP4203731B2 JP 4203731 B2 JP4203731 B2 JP 4203731B2 JP 2003146769 A JP2003146769 A JP 2003146769A JP 2003146769 A JP2003146769 A JP 2003146769A JP 4203731 B2 JP4203731 B2 JP 4203731B2
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reaction tube
deposition
optical fiber
glass
manufacturing
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JP2004345924A (en
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信次 遠藤
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Sumitomo Electric Industries 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]
    • C03B37/018—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
    • C03B2207/00—Glass deposition burners
    • C03B2207/60—Relationship between burner and deposit, e.g. position
    • C03B2207/66—Relative motion
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/70—Control measures

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  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
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  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)

Description

【０００１】
【発明の属する技術分野】
この発明は、光ファイバ用ガラス母材の製造方法に関するものである。
【０００２】
【従来の技術】
従来の光ファイバ用ガラス母材の製造方法および製造装置として、石英からなる反応管を回転させ、反応管の内部に原料ガスを供給するとともに反応管を外側から加熱することにより、反応管の内面にガラス層を堆積させるいわゆるＭＣＶＤ法によるものが開示されている（例えば、特許文献１参照。）。
この特許文献１に示されているＭＣＶＤ法では、加熱源を反応管の外側において軸方向に沿って往復移動させる際に、下流側の移動終了端を徐々に上流側へ移動させるようにしている。これにより、ガラス層の堆積部分の末端における反応管の破損を防止するとともに、ススの堆積を低減している。
【０００３】
【特許文献１】
特開平６−２７１３２９号公報（第５−７頁、第１図）
【０００４】
【発明が解決しようとする課題】
ところで、ＭＣＶＤ法によるガラス堆積では、図３に示すように、堆積の開始側と終了側でガラス堆積量の違いが発生し、それがファイバ化したときに長手方向での特性変動の原因となる。
これは、図４に示すように、反応管１００の内部でガラス層１０１が生成される反応において、堆積開始時である上流側では内部温度が低いためガラスの生成量が少なく、その後徐々に堆積が進行して平衡状態に達するまでに時間差がある。その結果、図４に示すように、有効部におけるガラス層１０１の堆積量が上流側と下流側とで異なり、反応管１００の肉厚に差が生じるためである。
【０００５】
さらに、図５に示すように、ガラス層１０１が堆積して反応管１００の肉厚が厚くなるに従って、ガラス層１０１の堆積が平衡に達するまでの遅延も大きくなる。すなわち、肉厚が薄い場合の遅延時間ＴＬ０よりも肉厚が厚い場合の遅延時間ＴＬ１の方が長くなる（ＴＬ０＜ＴＬ１）。このことも、ファイバ化したときの特性の長手方向変動を引き起こす要因となる。
なお、図５においては、ガラス層１０１が堆積して反応管１００の肉厚が変化した場合を示し、反応管１００の表面温度は同一温度に設定されている。
【０００６】
本発明の目的は、反応管の内部に堆積するガラス層の厚さを均一にすることにより、長手方向の特性変動を小さくすることのできる光ファイバ用ガラス母材の製造方法を提供することにある。
【０００７】
【課題を解決するための手段】
前述した目的を達成するために、本発明にかかる光ファイバ用ガラス母材の製造方法は、回転する反応管の内部に上流側から原料ガスを供給し、前記反応管を外側から加熱する熱源を上流側から下流側へ移動させて前記反応管の内部にガラス層を堆積させる光ファイバ用ガラス母材の製造方法であって、堆積開始端を段階的に上流側へ移動させることを特徴としている。
【０００８】
このように構成された光ファイバ用ガラス母材の製造方法においては、反応管に上流側から原料ガスを供給しながら回転させ、熱源を反応管の長手方向へ往復移動させて加熱して反応管の内部にガラス層を堆積させる。この際に、堆積開始端である熱源の移動範囲の上流側端を段階的に上流側へ移動させる。これにより、堆積により反応管の肉厚が厚くなることに伴って伸びる堆積開始端から堆積が平衡状態になるまでの過渡状態を有効部よりも上流側へ移動させ、製造されるガラス母材の有効部におけるガラス層の堆積量を均一にする。
【０００９】
【発明の実施の形態】
以下、本発明に係る光ファイバ用ガラス母材の製造方法および製造装置の実施の形態を図面に基づいて詳細に説明する。なお、図１は本発明に係る光ファイバ用ガラス母材の製造装置の正面図、図２は本発明に係る光ファイバ用ガラス母材の製造方法および製造装置により製造したガラス母材におけるガラス層の堆積状態を示す断面図である。
【００１０】
図１に示すように、光ファイバ用ガラス母材の製造装置１０は、基台１１の上面１１ａの上流側端部（図１において左側端部）および下流側端部に支柱１２、１２が各々立設されている。支柱１２、１２の上端部には、石英からなる反応管２０を保持する保持部１３が回転自在に設けられている。基台１１の上面１１ａの両支柱１２、１２間には、熱源移動機構である台座１４がモータ１５により往復移動自在に設けられており、熱源１７が取り付けられている。なお、モータ１５は制御装置３０により制御される。
【００１１】
台座１４には位置検出器１６が取り付けられており、台座１４の位置を制御装置３０に伝達するようになっている。位置検出器１６としては、モータ１５にロータリーエンコーダを取り付けて、モータ１５の回転数から位置を検出するようにすることができる。あるいは、基台１１にリニアスケールを設けておき、台座１４に設けた検出子により位置を検出するようにすることもできる。
【００１２】
制御装置３０は、モータ１５を制御して台座１４を往復移動させるモータ制御部３１、熱源１７の移動範囲の上流側端である堆積開始端ＰＵｉ（図２参照）を往復移動回数に対応して段階的に上流側へ移動するように設定する往復範囲指令部３２、台座１４に設けられている位置検出器１６からの位置信号を受けて設定された往復範囲と比較する比較部３３等を備えている。
【００１３】
次に、本発明に係る光ファイバ用ガラス母材の製造方法について説明する。保持部１３により保持されている反応管２０を回転させながら、原料ガス供給手段２１が上流側から反応管２０の内部に例えば四塩化ケイ素、三塩化ホウ素等の原料ガスを供給する。そして、モータ１５により台座１４を移動させて、熱源１７を反応管２０の長手方向に沿って上流側から下流側へ往復移動しながら反応管２０を外側から加熱して、反応管２０の内部にガラス層２２（図２参照）を堆積させる。
【００１４】
このとき、制御装置３０の往復範囲指令部３２は堆積開始端ＰＵｉを段階的に上流側へ移動させて往復範囲を設定する。比較部３３は位置検出器１６からの位置信号と往復範囲とを比較し、台座１４が往復範囲に収まるように、モータ制御部３１が熱源移動機構のモータ１５を制御して台座１４を往復移動させる。
【００１５】
従って、図２に示されるように、堆積開始端ＰＵｉが上流側へ移動するに伴って、堆積が平衡となる位置も上流側へ移動することになる。これにより、図５において前述したように、ガラス層２２の堆積によって反応管２０の肉厚が厚くなることに伴い、堆積が平衡となるまでの時間が延びるのを吸収するので、有効部においては常に均一なガラス層２２の堆積が得られることになる。
なお、有効部の上流側に生じる非有効部が長くなるため、反応管２０の無駄を少なくするためにダミーパイプをつけるようにするのが好ましい。
【００１６】
次に、上述した光ファイバ用ガラス母材の製造方法および製造装置により製造した具体的な実施例について説明する。
表１には、本発明により堆積開始端ＰＵｉを上流側へ移動させながら製造した場合の堆積したガラス層２２の厚みと、従来の堆積開始端位置が一定の場合における堆積したガラス層の厚みを比較した結果が示されている。
なお、本発明における堆積開始端ＰＵｉの移動量は、熱源１７の２０往復ごとに５０ｍｍずつ上流側へ移動した。その他、熱源１７の温度や原料ガスの流量等は一定とした。
【００１７】
【表１】

Figure 0004203731
【００１８】
従来方式では、下流側に堆積したガラス層の厚さと上流側に堆積したガラス層の厚さの差は、堆積トラバース回数（熱源の往復回数）が２０のときに０．０１９ｍｍであり、その後４０回、６０回、８０回、１００回とトラバース回数にほぼ比例して厚さの差が増加している。すなわち、有効部においても下流側に堆積するガラス層が厚く、上流側に堆積するガラス層の厚さが小さくなっており、ガラス層の堆積量が長手方向に均一になっていないことがわかる。
【００１９】
一方、本発明では、下流側に堆積したガラス層２２の厚さと上流側に堆積したガラス層２２の厚さの差は、堆積トラバース回数が２０回の時と１００回の時とであまり差がない。従って、堆積トラバース回数が１００回の場合には、本発明の光ファイバ用ガラス母材の製造方法によると、上流側と下流側の厚さの差が従来式による場合と比較して約８分の１に小さくなっていることがわかる。すなわち、本発明では堆積するガラス層２２の厚さが、長手方向に均一となっていることがわかる。
【００２０】
以上、前述した光ファイバ用ガラス母材の製造方法および製造装置によれば、堆積開始端ＰＵｉである熱源１７の移動範囲の上流側端を段階的に上流側へ移動させることにより、堆積によって反応管２０の肉厚が厚くなることに伴って伸びる堆積開始端ＰＵｉから堆積が平衡状態になるまでの過渡状態を有効部よりも上流側へ移動させる。これにより、有効部におけるガラス層２２の堆積量を均一にすることができ、ファイバ化したときの長手方向の特性の変動を小さくすることができる。
【００２１】
なお、本発明の光ファイバ用ガラス母材の製造方法および製造装置は、前述した実施形態に限定されるものでなく、適宜な変形、改良等が可能である。
例えば、前述した製造装置１０における熱源移動機構として、台座１４に設けたモータ１５によって自走するタイプのものを例示したが、この他、モータにより回転するボールネジを反応管２０に沿って基台１１に設けておき、台座１４にこのボールネジに螺合しボールネジに沿って往復移動するボールナットを取り付けるようにしても良い。
【００２２】
【発明の効果】
以上、説明したように、本発明にかかる光ファイバ用ガラス母材の製造方法によれば、反応管に上流側から原料ガスを供給しながら回転させ、熱源を反応管の長手方向へ移動させて加熱して反応管の内部にガラス層を堆積させる。この際に、堆積開始端である熱源の移動範囲の上流側端を段階的に上流側へ移動させる。これにより、堆積により反応管の肉厚が厚くなることに伴って伸びる堆積開始端から反応が平衡状態になるまでの過渡状態を有効部よりも上流側へ移動させ、有効部におけるガラス層の堆積量を均一にすることができ、ファイバ化したときの長手方向の特性の変動を小さくすることができる。
【図面の簡単な説明】
【図１】本発明に係る光ファイバ用ガラス母材の製造装置の実施形態を示す構成図である。
【図２】本発明に係る光ファイバ用ガラス母材の製造方法および製造方法により反応管の内部に堆積したガラス層の厚さを示す断面図である。
【図３】従来より知られている堆積開始点から反応が平衡となるまでの過渡状態を示すグラフである。
【図４】従来法により反応管の内部に堆積したガラス層の厚さを示す断面図である。
【図５】反応管の肉厚と過渡状態の関係を示すグラフである。
【符号の説明】
１０ 光ファイバ用ガラス母材の製造装置
１５ モータ（熱源移動機構）
１７ 熱源
２０ 反応管
２１ 原料ガス供給手段
２２ ガラス層
３０ 制御装置
ＰＵｉ 堆積開始端[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a glass preform for an optical fiber.
[0002]
[Prior art]
As a conventional method and apparatus for producing a glass preform for an optical fiber, an inner surface of a reaction tube is obtained by rotating a reaction tube made of quartz, supplying a raw material gas into the reaction tube and heating the reaction tube from the outside. A so-called MCVD method in which a glass layer is deposited is disclosed (for example, see Patent Document 1).
In the MCVD method disclosed in Patent Document 1, when the heating source is reciprocated along the axial direction outside the reaction tube, the end of movement on the downstream side is gradually moved to the upstream side. . This prevents breakage of the reaction tube at the end of the deposited portion of the glass layer and reduces soot deposition.
[0003]
[Patent Document 1]
JP-A-6-271329 (page 5-7, FIG. 1)
[0004]
[Problems to be solved by the invention]
By the way, in the glass deposition by the MCVD method, as shown in FIG. 3, a difference in the amount of glass deposition occurs between the deposition start side and the termination side, which causes fluctuations in characteristics in the longitudinal direction when the fiber is formed. .
This is because, as shown in FIG. 4, in the reaction in which the glass layer 101 is generated inside the reaction tube 100, the amount of glass generated is small because the internal temperature is low on the upstream side at the start of deposition, and then gradually deposited. There is a time difference until the equilibrium state is reached. As a result, as shown in FIG. 4, the deposition amount of the glass layer 101 in the effective portion is different between the upstream side and the downstream side, and the thickness of the reaction tube 100 is different.
[0005]
Further, as shown in FIG. 5, as the glass layer 101 is deposited and the thickness of the reaction tube 100 is increased, the delay until the deposition of the glass layer 101 reaches equilibrium increases. That is, the delay time TL1 when the wall thickness is large is longer than the delay time TL0 when the wall thickness is thin (TL0 <TL1). This is also a factor that causes longitudinal fluctuations in characteristics when formed into a fiber.
FIG. 5 shows a case where the thickness of the reaction tube 100 changes due to the deposition of the glass layer 101, and the surface temperature of the reaction tube 100 is set to the same temperature.
[0006]
An object of the present invention is to provide a method for producing a glass preform for an optical fiber, which can reduce the characteristic fluctuation in the longitudinal direction by making the thickness of the glass layer deposited inside the reaction tube uniform. is there.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, a method for manufacturing a glass preform for an optical fiber according to the present invention includes a heat source for supplying a raw material gas from an upstream side into a rotating reaction tube and heating the reaction tube from the outside. A method of manufacturing a glass preform for an optical fiber that moves from an upstream side to a downstream side to deposit a glass layer inside the reaction tube, characterized in that the deposition start end is moved stepwise to the upstream side. .
[0008]
In the manufacturing method of the optical fiber glass preform thus configured, the reaction tube is rotated while supplying the raw material gas from the upstream side, and the heat source is reciprocated in the longitudinal direction of the reaction tube to heat it. A glass layer is deposited inside. At this time, the upstream end of the moving range of the heat source that is the deposition start end is moved to the upstream side stepwise. As a result, the transient state from the deposition start end extending as the reaction tube becomes thicker due to the deposition until the deposition reaches an equilibrium state is moved to the upstream side from the effective portion, and the glass base material to be manufactured is moved. The amount of the glass layer deposited in the effective part is made uniform.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for manufacturing an optical fiber glass preform and a manufacturing apparatus according to the present invention will be described below in detail with reference to the drawings. 1 is a front view of an optical fiber glass base material manufacturing apparatus according to the present invention, and FIG. 2 is a glass layer in a glass base material manufactured by the optical fiber glass base material manufacturing method and manufacturing apparatus according to the present invention. It is sectional drawing which shows the deposition state of.
[0010]
As shown in FIG. 1, the optical fiber glass preform manufacturing apparatus 10 has columns 12 and 12 at the upstream end (the left end in FIG. 1) and the downstream end of the upper surface 11 a of the base 11. It is erected. A holding portion 13 that holds a reaction tube 20 made of quartz is rotatably provided at the upper end portion of the support columns 12 and 12. A pedestal 14, which is a heat source moving mechanism, is provided between the columns 12, 12 on the upper surface 11 a of the base 11 so as to be reciprocally movable by a motor 15, and a heat source 17 is attached. The motor 15 is controlled by the control device 30.
[0011]
A position detector 16 is attached to the base 14 so that the position of the base 14 is transmitted to the control device 30. As the position detector 16, a rotary encoder can be attached to the motor 15 so that the position can be detected from the number of rotations of the motor 15. Alternatively, a linear scale may be provided on the base 11 and the position may be detected by a detector provided on the base 14.
[0012]
The control device 30 controls the motor 15 to reciprocate the pedestal 14 and the deposition start end PUi (see FIG. 2), which is the upstream end of the moving range of the heat source 17, corresponding to the number of reciprocating movements. A reciprocating range command unit 32 that is set so as to move upstream in stages, a comparison unit 33 that receives a position signal from the position detector 16 provided on the pedestal 14 and compares it with a set reciprocating range are provided. ing.
[0013]
Next, the manufacturing method of the glass preform for optical fibers according to the present invention will be described. The source gas supply means 21 supplies a source gas such as silicon tetrachloride or boron trichloride from the upstream side to the inside of the reaction tube 20 while rotating the reaction tube 20 held by the holding unit 13. Then, the pedestal 14 is moved by the motor 15, and the reaction tube 20 is heated from the outside while reciprocating the heat source 17 from the upstream side to the downstream side along the longitudinal direction of the reaction tube 20. A glass layer 22 (see FIG. 2) is deposited.
[0014]
At this time, the reciprocating range command unit 32 of the control device 30 sets the reciprocating range by moving the deposition start end PUi to the upstream side stepwise. The comparison unit 33 compares the position signal from the position detector 16 with the reciprocating range, and the motor control unit 31 controls the motor 15 of the heat source moving mechanism to reciprocate the pedestal 14 so that the pedestal 14 is within the reciprocating range. Let
[0015]
Therefore, as shown in FIG. 2, as the deposition start end PUi moves upstream, the position at which the deposition is balanced also moves upstream. Accordingly, as described above with reference to FIG. 5, as the thickness of the reaction tube 20 increases due to the deposition of the glass layer 22, it absorbs an increase in time until the deposition reaches equilibrium. A uniform deposition of the glass layer 22 is always obtained.
In addition, since the non-effective part produced on the upstream side of the effective part becomes long, it is preferable to attach a dummy pipe in order to reduce the waste of the reaction tube 20.
[0016]
Next, the specific Example manufactured with the manufacturing method and manufacturing apparatus of the glass base material for optical fibers mentioned above is described.
Table 1 shows the thickness of the deposited glass layer 22 when the deposition start end PUi is manufactured while being moved upstream according to the present invention, and the thickness of the deposited glass layer when the conventional deposition start end position is constant. The comparison results are shown.
Note that the amount of movement of the deposition start end PUi in the present invention moved upstream by 50 mm for every 20 reciprocations of the heat source 17. In addition, the temperature of the heat source 17 and the flow rate of the source gas were set constant.
[0017]
[Table 1]
Figure 0004203731
[0018]
In the conventional method, the difference between the thickness of the glass layer deposited on the downstream side and the thickness of the glass layer deposited on the upstream side is 0.019 mm when the number of times of deposition traverse (the number of reciprocations of the heat source) is 20, and then 40 The difference in thickness increases almost in proportion to the number of times of traversing times, 60 times, 80 times, 100 times. That is, it can be seen that the glass layer deposited on the downstream side is also thick in the effective portion, the thickness of the glass layer deposited on the upstream side is small, and the deposition amount of the glass layer is not uniform in the longitudinal direction.
[0019]
On the other hand, in the present invention, the difference between the thickness of the glass layer 22 deposited on the downstream side and the thickness of the glass layer 22 deposited on the upstream side is not so different between when the number of deposition traverses is 20 times and when it is 100 times. Absent. Therefore, when the number of deposition traverses is 100, according to the method for manufacturing a glass preform for an optical fiber of the present invention, the difference in thickness between the upstream side and the downstream side is about 8 minutes as compared with the case of the conventional method. It can be seen that it is smaller to 1. That is, in the present invention, it can be seen that the thickness of the deposited glass layer 22 is uniform in the longitudinal direction.
[0020]
As mentioned above, according to the manufacturing method and manufacturing apparatus of the glass base material for optical fibers mentioned above, it reacts by deposition by moving the upstream side end of the movement range of the heat source 17 which is the deposition start end PUi to the upstream side stepwise. The transient state from the deposition start end PUi extending as the thickness of the tube 20 increases to the equilibrium state is moved to the upstream side of the effective portion. Thereby, the deposition amount of the glass layer 22 in an effective part can be made uniform, and the fluctuation | variation of the characteristic of the longitudinal direction when it makes into a fiber can be made small.
[0021]
In addition, the manufacturing method and manufacturing apparatus of the glass base material for optical fibers of this invention are not limited to embodiment mentioned above, A suitable deformation | transformation, improvement, etc. are possible.
For example, as the heat source moving mechanism in the manufacturing apparatus 10 described above, a type that is self-propelled by the motor 15 provided on the pedestal 14 is illustrated, but in addition, a ball screw that is rotated by the motor is connected to the base 11 along the reaction tube 20. The ball nut may be attached to the pedestal 14 so as to be engaged with the ball screw and reciprocally moved along the ball screw.
[0022]
【The invention's effect】
As described above, according to the method for manufacturing a glass preform for an optical fiber according to the present invention, the reaction tube is rotated while supplying the raw material gas from the upstream side, and the heat source is moved in the longitudinal direction of the reaction tube. Heat to deposit a glass layer inside the reaction tube. At this time, the upstream end of the moving range of the heat source that is the deposition start end is moved to the upstream side stepwise. As a result, the transient state from the deposition start end, which is extended as the reaction tube becomes thicker due to deposition, until the reaction reaches an equilibrium state is moved upstream from the effective portion, and the glass layer is deposited in the effective portion. The amount can be made uniform, and fluctuations in the characteristics in the longitudinal direction when the fiber is formed can be reduced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of an optical fiber glass preform manufacturing apparatus according to the present invention.
FIG. 2 is a cross-sectional view showing the thickness of a glass layer deposited in a reaction tube by the manufacturing method of an optical fiber glass preform according to the present invention and the manufacturing method.
FIG. 3 is a graph showing a transient state from the deposition start point known until now until the reaction reaches equilibrium.
FIG. 4 is a cross-sectional view showing the thickness of a glass layer deposited inside a reaction tube by a conventional method.
FIG. 5 is a graph showing the relationship between the thickness of a reaction tube and a transient state.
[Explanation of symbols]
10 Optical Fiber Glass Base Material Manufacturing Equipment 15 Motor (Heat Source Movement Mechanism)
17 Heat source 20 Reaction tube 21 Raw material gas supply means 22 Glass layer 30 Controller PUi Deposition start end

Claims (1)

回転する反応管の内部に上流側から原料ガスを供給し、前記反応管を外側から加熱する熱源を上流側から下流側へ移動させて前記反応管の内部にガラス層を堆積させる光ファイバ用ガラス母材の製造方法であって、
堆積開始端を段階的に上流側へ移動させることを特徴とする光ファイバ用ガラス母材の製造方法。An optical fiber glass in which a source gas is supplied into the rotating reaction tube from the upstream side, and a heat source for heating the reaction tube from the outside is moved from the upstream side to the downstream side to deposit a glass layer inside the reaction tube. A method of manufacturing a base material,
A method for producing a glass preform for an optical fiber, characterized in that the deposition start end is moved stepwise upstream.
JP2003146769A 2003-05-23 2003-05-23 Manufacturing method of glass preform for optical fiber Expired - Fee Related JP4203731B2 (en)

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