JPH0154288B2 - - Google Patents
Info
- Publication number
- JPH0154288B2 JPH0154288B2 JP15968984A JP15968984A JPH0154288B2 JP H0154288 B2 JPH0154288 B2 JP H0154288B2 JP 15968984 A JP15968984 A JP 15968984A JP 15968984 A JP15968984 A JP 15968984A JP H0154288 B2 JPH0154288 B2 JP H0154288B2
- Authority
- JP
- Japan
- Prior art keywords
- glass
- dopant
- burner
- layer
- raw material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000011521 glass Substances 0.000 claims description 44
- 239000002019 doping agent Substances 0.000 claims description 24
- 239000013307 optical fiber Substances 0.000 claims description 22
- 239000004071 soot Substances 0.000 claims description 21
- 239000002994 raw material Substances 0.000 claims description 16
- 230000008021 deposition Effects 0.000 claims description 10
- 239000002245 particle Substances 0.000 claims description 10
- 238000007496 glass forming Methods 0.000 claims description 9
- 238000006460 hydrolysis reaction Methods 0.000 claims description 9
- 150000001875 compounds Chemical class 0.000 claims description 8
- 230000007062 hydrolysis Effects 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 230000008018 melting Effects 0.000 claims description 5
- 238000002844 melting Methods 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 4
- 239000010410 layer Substances 0.000 description 35
- 239000000463 material Substances 0.000 description 24
- 238000005253 cladding Methods 0.000 description 20
- 239000007789 gas Substances 0.000 description 20
- 238000000034 method Methods 0.000 description 12
- 238000000151 deposition Methods 0.000 description 11
- 230000005540 biological transmission Effects 0.000 description 9
- 238000005229 chemical vapour deposition Methods 0.000 description 6
- 239000012792 core layer Substances 0.000 description 6
- 239000010419 fine particle Substances 0.000 description 6
- 229910003902 SiCl 4 Inorganic materials 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 238000009826 distribution Methods 0.000 description 5
- 230000001788 irregular Effects 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 229910005793 GeO 2 Inorganic materials 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- RLOWWWKZYUNIDI-UHFFFAOYSA-N phosphinic chloride Chemical compound ClP=O RLOWWWKZYUNIDI-UHFFFAOYSA-N 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000012159 carrier gas Substances 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229910052736 halogen Inorganic materials 0.000 description 2
- 150000002367 halogens Chemical class 0.000 description 2
- 239000005373 porous glass Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 229910004721 HSiCl3 Inorganic materials 0.000 description 1
- 229910003910 SiCl4 Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical group 0.000 description 1
- 238000011534 incubation Methods 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- JLUFWMXJHAVVNN-UHFFFAOYSA-N methyltrichlorosilane Chemical compound C[Si](Cl)(Cl)Cl JLUFWMXJHAVVNN-UHFFFAOYSA-N 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 150000003377 silicon compounds Chemical class 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- FDNAPBUWERUEDA-UHFFFAOYSA-N silicon tetrachloride Chemical compound Cl[Si](Cl)(Cl)Cl FDNAPBUWERUEDA-UHFFFAOYSA-N 0.000 description 1
- 229920002050 silicone resin Polymers 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- ZDHXKXAHOVTTAH-UHFFFAOYSA-N trichlorosilane Chemical compound Cl[SiH](Cl)Cl ZDHXKXAHOVTTAH-UHFFFAOYSA-N 0.000 description 1
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]
- C03B37/01413—Reactant delivery systems
- C03B37/0142—Reactant deposition burners
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/06—Doped silica-based glasses
- C03B2201/30—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi
- C03B2201/31—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with germanium
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/10—Internal structure or shape details
- C03B2203/22—Radial profile of refractive index, composition or softening point
- C03B2203/26—Parabolic or graded index [GRIN] core profile
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2207/00—Glass deposition burners
- C03B2207/04—Multi-nested ports
- C03B2207/06—Concentric circular ports
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2207/00—Glass deposition burners
- C03B2207/20—Specific substances in specified ports, e.g. all gas flows specified
- C03B2207/26—Multiple ports for glass precursor
- C03B2207/28—Multiple ports for glass precursor for different glass precursors, reactants or modifiers
-
- 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
- C03B2207/62—Distance
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は伝送損失の改良された光フアイバ用ガ
ラス母材の製造方法に関するものであり、特に光
が伝搬するコアとクラツドの境界面およびクラツ
ドの一部において屈折率のイレギユラー（不規則
な変化）がない低損失の正規分布型シングルモー
ド光フアイバ用ガラス母材の製造方法に関する。Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for manufacturing a glass base material for optical fibers with improved transmission loss, and particularly relates to a method for manufacturing a glass base material for optical fibers with improved transmission loss. The present invention relates to a method for manufacturing a glass base material for a normally distributed single mode optical fiber with low loss and no irregularity (irregular change) in the refractive index in a part of the fiber.
（従来の技術）
光フアイバに関し伝送損失をもたらす原因とし
ては種々の吸収損失、散乱損失があり、こうした
伝送損失を改良することならびに屈折率のイレギ
ユラーを改良することは、高性能光フアイバを得
るうえからきわめて重要な課題であり、光フアイ
バの構造設計、製造技術等の観点から多くの研究
が行われている。(Prior art) There are various absorption losses and scattering losses that cause transmission loss in optical fibers, and improving these transmission losses and irregularities in refractive index are important in obtaining high-performance optical fibers. This is an extremely important issue, and much research is being conducted from the viewpoints of optical fiber structural design, manufacturing technology, etc.
従来、光フアイバ用ガラス母材の製法として、
中心棒の周りに酸水素バーナによりガラス原料ガ
ス（SiCl4等）を火炎加水分解することにより生
成するガラス微粒子を何層にも堆積させ、中心棒
を引抜いた後溶融透明化する方法（外付けCVD
法）が知られている。この方法においては一層毎
のガラス（シリカ）の付着が十分強固であること
が必要であるため強力な火炎を使用するのである
が、各層間でドープ剤の濃度に大きな変動のある
ことが指摘されており、屈折率のイレギユラーと
いう欠点がある。他方ガラス管内にガラス原料ガ
スを流し高温に加熱することにより管内壁に化学
蒸着させる方法（内付けCVD法）においてもイ
レギユラーの問題がある。 Conventionally, as a manufacturing method for glass base material for optical fiber,
A method in which glass fine particles produced by flame hydrolysis of frit gas (SiCl 4 , etc.) using an oxyhydrogen burner are deposited in many layers around the center rod, and after the center rod is pulled out, they are melted and made transparent (externally attached). CVD
law) is known. In this method, a strong flame is used because it is necessary for the adhesion of glass (silica) in each layer to be sufficiently strong, but it has been pointed out that there is a large variation in the concentration of the dopant between each layer. The disadvantage is that the refractive index is irregular. On the other hand, the method of chemical vapor deposition on the inner wall of a glass tube (internal CVD method) by flowing frit gas into a glass tube and heating it to a high temperature also has irregular problems.
上記したCVD法に対し、回転するターゲツト
棒の先端に、高温ガス中でSiCl4等の原料から生
成されたガラス微粒子を吹き付けることにより軸
方向に堆積させスート層を形成する方法（VAD
法）が開発され、量産性の向上がはかられた。し
かしこの方法においてはコア層およびクラツド層
の形成に当つて、まず第一のバーナでコアスート
層を形成し次にそのコアスート層を一たん溶融透
明化するかまたはスートの上に直接第二のバーナ
によつてクラツドスート層を形成する方法が採ら
れたり、あるいはまたシングルモード光フアイバ
製造のときのように複数本のバーナが用いられる
が、これらの場合に各層間（境界層）で大きなイ
レギユラーが生じ、伝送損失がもたらされるとい
う問題がある。 In contrast to the above-mentioned CVD method, a method (VAD) in which a soot layer is formed by spraying glass particles generated from raw materials such as SiCl 4 in a high-temperature gas onto the tip of a rotating target rod to deposit them in the axial direction.
A new method was developed to improve mass productivity. However, in this method, when forming the core layer and cladding layer, first a core soot layer is formed using a first burner, and then the core soot layer is temporarily melted and made transparent, or a second burner is used directly on top of the soot. In some cases, a method is adopted to form a clad soot layer, or multiple burners are used as in the production of single-mode optical fibers, but in these cases large irregularities occur between each layer (boundary layer). , there is a problem that transmission loss is introduced.
（発明の構成）
本発明者らはかかる技術的課題に対し鋭意研究
を重ねた結果、条件を設定することにより一本の
同心多重管バーナで、ドープ剤を含むコアスート
層とドープ剤を実質的に含まないクラツドスート
層を同時に堆積生長させることが可能となるこ
と、およびこれから本質的に層間の屈折率イレギ
ユラーがない伝送損失の顕著に改良された光フア
イバが得られることを確認し本発明を完成した。(Structure of the Invention) As a result of intensive research into the technical problem, the present inventors found that by setting conditions, a core soot layer containing a dopant and a dopant can be substantially removed using a single concentric multi-tube burner. The present invention was completed by confirming that it is possible to simultaneously deposit and grow a clad soot layer that does not contain cladding, and that this results in an optical fiber with significantly improved transmission loss that is essentially free of interlayer refractive index irregularities. did.
すなわち本発明は一本の同心多重管バーナより
形成される酸水素炎の中に、ガラス形成原料化合
物とドープ剤とからなる均一組成の原料ガスを該
バーナの一本の中心ノズルから噴出せしめて火炎
加水分解し、この火炎加水分解で形成されるガラ
ス微粒子が堆積される堆積面と該バーナ出口端面
との距離を50mm以上に維持しながら、生成ガラス
微粒子を回転しているターゲツトの先端に吹き付
け軸方向に堆積生長させることにより、ドープ剤
を含むコアスート層とドープ剤を実質的に含まな
いクラツドスート層とを同時に形成し、溶融透明
化することを特徴とする光フアイバ用ガラス母材
の製造方法に関するものである。 That is, the present invention injects a raw material gas of a uniform composition consisting of a glass-forming raw material compound and a dopant from a single central nozzle of the burner into an oxyhydrogen flame formed by a single concentric multi-tube burner. Flame hydrolysis is performed, and while maintaining a distance of 50 mm or more between the deposition surface on which glass particles formed by this flame hydrolysis are deposited and the end face of the burner outlet, the generated glass particles are sprayed onto the tip of a rotating target. A method for producing a glass base material for optical fiber, characterized by simultaneously forming a core soot layer containing a dopant and a clad soot layer substantially free of a dopant by depositing and growing in the axial direction, and melting and making the base material transparent. It is related to.
以下本発明を詳細に説明する。 The present invention will be explained in detail below.
本発明は基本的にはガラス形成原料ガスを酸水
素炎中で加熱反応（火炎加水分解）させることに
よりガラス微粒子を発生させ、これを回転機構の
ついているターゲツトの先端に吹き付け軸方向に
堆積生長させ、堆積量に応じて移動させ円柱状の
ガラススート（多孔質体）をつくり、つぎにこの
スートを溶融透明化することにより光フアイバ用
ガラス母材を得るVAD法技術と関連するもので
あるが、次の事項が重要な要件とされる。 Basically, the present invention generates glass fine particles by subjecting glass forming raw material gas to a heating reaction (flame hydrolysis) in an oxyhydrogen flame, which is then blown onto the tip of a target equipped with a rotating mechanism to deposit and grow in the axial direction. This is related to the VAD method technology, which creates a cylindrical glass soot (porous body) by moving it according to the amount of deposition, and then melting and making this soot transparent to obtain a glass base material for optical fibers. However, the following items are considered important requirements.
(1) 一本の同心多重管バーナで操作する（従来の
VAD法においてシングルモード光フアイバを
作る場合にはバーナが２本またはそれ以上用い
ることが必須であつた）。バーナを２本以上用
いると炎の干渉による温度分布やガスの流れな
どが境界層で不連続となりこの結果屈折率イレ
ギユラーを解消することができない。(1) Operate with a single concentric multi-tube burner (conventional
When making a single mode optical fiber using the VAD method, it was essential to use two or more burners). If two or more burners are used, the temperature distribution and gas flow due to flame interference become discontinuous in the boundary layer, and as a result, refractive index irregularities cannot be eliminated.
(2) ガラス形成原料ガスは、ガラス形成原料化合
物とドープ剤とを均一組成に混合した状態で該
バーナの一本の中心ノズルから噴出させる。(2) The glass-forming raw material gas is ejected from one central nozzle of the burner in a state in which the glass-forming raw material compound and the dopant are mixed to have a uniform composition.
ガラス形成原料化合物とドープ剤とを均一混
合せずに別々のノズルから噴出させると、屈折
率イレギユラーが生じスムーズなプロフアイル
をした正規分布型シングルモード光フアイバ用
ガラス母材を得ることができない。 If the glass-forming raw material compound and the dopant are ejected from separate nozzles without being uniformly mixed, irregular refractive index occurs, making it impossible to obtain a glass base material for a normally distributed single mode optical fiber with a smooth profile.
(3) バーナ出口端面と生成ガラス微粒子を堆積さ
せる堆積面との距離を50mm以上に維持する。こ
の距離が短かすぎると、ドープ剤を実質的に含
まないクラツド層の形成が困難となり、正規分
布型シングルモード光フアイバ用ガラス母材を
得ることができない。(3) Maintain a distance of 50 mm or more between the end face of the burner outlet and the deposition surface on which the generated glass particles are deposited. If this distance is too short, it will be difficult to form a cladding layer that does not substantially contain a dopant, making it impossible to obtain a glass preform for a normally distributed single mode optical fiber.
(4) 上記した(1)〜(3)の条件のもとに、火炎加水分
解で形成されるガラス微粒子を軸方向に堆積生
長させることにより、ドープ剤を含むコアスー
ト層とドープ剤を実質的に含まないクラツドス
ート層とを同時に形成する。(4) Under the conditions (1) to (3) above, glass fine particles formed by flame hydrolysis are deposited and grown in the axial direction, thereby substantially removing the core soot layer containing the dopant and the dopant. A clad soot layer not included in the cladding layer is formed at the same time.
このようにして製造された多孔質ガラス母材
は、適宜ハロゲンガス等により高温で脱水処理を
施した後加熱により溶融透明化する。このものは
軸方向と直角の切断面についてＸ線マイクロアナ
ライザで調べると、ドープ剤を含むコア層とドー
プ剤を実質的に含まないクラツド層が形成されて
おり、かつ全面にわたつて屈折率イレギユラーが
全く無いことが確認される。 The porous glass base material produced in this manner is suitably dehydrated at a high temperature using halogen gas or the like, and then melted and made transparent by heating. When this material is examined with an X-ray microanalyzer on a cross section perpendicular to the axial direction, it is found that a core layer containing a dopant and a cladding layer that does not substantially contain a dopant are formed, and the refractive index is irregular over the entire surface. It is confirmed that there is no such thing.
屈折率およびコア径の測定からクラツド径が設
計値に達していない分は、上記溶融透明化の前ま
たは後で外付けCVD法等によりガラス微粒子を
所定量付着させるかまたは透明化した後石英ガラ
ス管をかぶせて溶融一体化することにより、所望
のシングルモード光フアイバ用母材（プリフオー
ム）が得られる。なお、正規分布型の屈折率分布
をもつ母材の実質コア径は最大屈折率の半値幅に
よつて近似的に示される。 If the cladding diameter does not reach the design value based on the measurement of the refractive index and core diameter, either attach a predetermined amount of glass fine particles by external CVD method, etc. before or after the above-mentioned melting and transparency, or use silica glass after making it transparent. A desired single-mode optical fiber preform can be obtained by covering the tubes and melting them together. Note that the substantial core diameter of the base material having a normal distribution type refractive index distribution is approximately expressed by the half-width of the maximum refractive index.
本発明の実施に使用されるガラス形成原料化合
物としては、精製されけい素化合物たとえば
SiCl4、HSiCl3、CH3SiCl3、Si（OR1）4、R2Si
（OR1）3（式中のR1、R2は同種または異種の一価
炭化水素基）があげられる。ドープ剤は火炎中焼
結、脱水反応等により濃度変化を受けるもので、
光フアイバ用としてはGe、Ｐ、Ｂ、Ｆの化合物
が例示されるが、特にGeのハロゲン化物、アル
コキシ化物等が好ましい。 The glass-forming raw material compounds used in the practice of the present invention include purified silicon compounds such as
SiCl4 , HSiCl3 , CH3SiCl3 , Si( OR1 ) 4 , R2Si
(OR 1 ) 3 (R 1 and R 2 in the formula are the same or different monovalent hydrocarbon groups). Dopants undergo concentration changes due to flame sintering, dehydration reactions, etc.
Compounds of Ge, P, B, and F are exemplified for use in optical fibers, and halides and alkoxides of Ge are particularly preferred.
ガラス形成原料化合物とドープ剤はそれぞれ別
のバブラー（ガス化装置）からキヤリアーガスに
より所定量を計量して搬送し少なくともバーナの
出口では完全に混合された均一組成のものとして
バーナのノズル（一本のノズル）のみから噴出さ
せ、この噴出原料ガスを酸水素炎で囲む（包む）
ような形で火炎加水分解させる。 The glass-forming raw material compound and the doping agent are each measured and transported in predetermined amounts by carrier gas from separate bubblers (gasifiers), and are completely mixed at least at the exit of the burner and delivered to the burner nozzle (one nozzle). The raw material gas is ejected only from the nozzle), and this ejected raw material gas is surrounded (wrapped) in an oxyhydrogen flame.
flame hydrolysis in the form of
ガラス形成原料化合物およびドープ剤の混合ガ
ス流体は火炎中で反応し、反応ゾーンは時間と共
に炎の内部に向けて進行する。すなわち混合原料
ガスは火炎中でバーナから離れているほど中心部
まで反応が進行しドープ剤を含まない層が増加し
ていくがバーナ出口端面から少なくとも50mm以上
離して標的（堆積面）に付着堆積させてガラスス
ートとなしこのものを溶融透明化すると、実質的
に必要なドープ剤を含んでいないクラツド層が形
成されるが、バーナ出口端面と堆積面との距離が
短かすぎるとドープ剤を含まないクラツド層の形
成が少なく同時合成で必要なクラツド層の形成が
困難となる。なお、該距離を150〜300mmにも離し
た場合にはクラツド層が大きくならすぎコア層と
なるべき中心部にもドープ剤がほとんど存在しな
くなるので、この距離は50〜150mmの範囲とする
ことが望ましい。ドープ剤を実質的に含まない外
周クラツド層の厚さは原料ガスの噴出速度やバー
ナの噴出径にも依存するので、これらの点につい
ても最適条件を設定することが望ましい。 A mixed gaseous fluid of glass-forming feedstock compounds and dopant reacts in the flame, and the reaction zone progresses into the interior of the flame over time. In other words, the farther the mixed raw material gas is from the burner in the flame, the more the reaction progresses to the center, and the layer that does not contain the dopant increases, but it is deposited on the target (deposition surface) at a distance of at least 50 mm from the end face of the burner outlet. When this material is melted and made transparent with glass soot, a clad layer that does not substantially contain the necessary dopant is formed, but if the distance between the burner exit end face and the deposition surface is too short, the dopant will be absorbed. Since the formation of a cladding layer that does not contain this material is small, it is difficult to form a cladding layer that is necessary by simultaneous synthesis. Note that if the distance is set to 150 to 300 mm, the cladding layer will become too large and there will be almost no dopant in the center, which should become the core layer, so this distance should be set in the range of 50 to 150 mm. is desirable. Since the thickness of the outer cladding layer, which does not substantially contain a dopant, also depends on the ejection speed of the source gas and the ejection diameter of the burner, it is desirable to set optimal conditions for these points as well.
ガラス微粒子を軸方向に堆積生長させて得た多
孔質ガラス母材は、ハロゲンガス雰囲気の中で脱
水化処理し高温で溶融透明化する。この透明化母
材はプリフオームアナライザ等により長手方向に
ついて屈折率、実質コア径、実質クラツド径を測
定し、クラツド層の不足分をさらに外周にクラツ
ド層を追加形成する。この追加クラツド層は石英
ガラス管をかぶせるロツドインチユーブ法が簡便
であるが、外付けCVD法により計算量のガラス
微粒子を堆積させる方が界面による散乱損失を少
なくするうえから適している。この堆積クラツド
層は脱水処理し溶融透明化して光フアイバ用ガラ
ス母材（プリフオーム）とする。 A porous glass base material obtained by depositing and growing glass particles in the axial direction is dehydrated in a halogen gas atmosphere and melted and made transparent at a high temperature. The refractive index, substantial core diameter, and substantial cladding diameter of this transparent base material are measured in the longitudinal direction using a preform analyzer or the like, and a cladding layer is additionally formed on the outer periphery to make up for the missing cladding layer. This additional cladding layer can be easily formed using the rod incubation method in which a quartz glass tube is covered, but it is more suitable to deposit a calculated amount of glass fine particles using the external CVD method in order to reduce scattering loss due to the interface. This deposited clad layer is dehydrated, melted and made transparent to form a glass preform for optical fiber.
このプリフオームを線引きし、コーテイングす
ることによりコア層とクラツド層からなる光フア
イバが得られる。 By drawing this preform and coating it, an optical fiber consisting of a core layer and a cladding layer is obtained.
つぎに実施例をあげる。 Next, an example will be given.
実施例 １
蒸留により精製したSiCl4、GeCl4、POCl3を
別々のガラス製パブラーに入れて各々の温度を25
℃、４℃、４℃に保つた。キヤリアーガスとして
アルゴンをパブラー内に通しパブリングさせるこ
とによりそれぞれガス化させた。これらの均一混
合ガス体を同心四重管バーナの中心ノズル口に供
給した（ただしそれぞれのパブラーにおけるアル
ゴンガスの流量を、
SiCl4のパブラー 0.6／分
GeCl4のパブラー 0.28／分
POCl3のパブラー 0.117／分
とした）。Example 1 SiCl 4 , GeCl 4 , and POCl 3 purified by distillation were placed in separate glass bubblers and the temperature of each was adjusted to 25°C.
It was kept at 4°C, 4°C, and 4°C. Argon was passed through a bubbler as a carrier gas and gasified by bubbling. These uniformly mixed gas bodies were supplied to the center nozzle port of a concentric quadruple tube burner (however, the flow rates of argon gas in each bubbler were as follows: SiCl 4 bubbler 0.6/min GeCl 4 bubbler 0.28/min POCl 3 bubbler 0.117 / minute).
またバーナの他のノズルにH23.4／分、O28.4
／分の割合で供給して酸水素炎を形成し、中心
ノズル口から噴出される均一混合原料ガスをこの
酸水素炎中で火炎加水分解反応させた。この反応
により形成されるガラス微粒子を、回転引上機構
の下端にとりつけた石英棒に下側から吹き付け、
軸方向に堆積生長させることにより円柱状のガラ
ススートを製造した。 Also, H 2 3.4/min and O 2 8.4 to other nozzles of the burner.
1/min to form an oxyhydrogen flame, and the homogeneous mixed raw material gas ejected from the center nozzle port was subjected to a flame hydrolysis reaction in this oxyhydrogen flame. The glass particles formed by this reaction are sprayed from below onto a quartz rod attached to the lower end of the rotating lifting mechanism.
Cylindrical glass soot was produced by axial deposition growth.
この際バーナ出口端面とガラス微粒子堆積面と
の距離を(1)20mm、(2)30mm、または(3)50mmとした。 At this time, the distance between the burner outlet end face and the glass particle deposition surface was set to (1) 20 mm, (2) 30 mm, or (3) 50 mm.
生長速度 2.5mm／分
平均堆積速度 30.5ｇ／hr
大きさ（直径） 70.2mm
重さ 110ｇ
見かけ密度 0.09ｇ／cm3
距離を前記(1)、(2)または(3)として得た各堆積ガ
ラススートを1600℃の炉内に入れ、Heガスを通
じながら溶融透明化した。これらのガラス母材を
５cmの厚さに輪切りにし、片面を研磨洗浄後島津
製作所製のＸ線マイクロアナライザでGeO2の濃
度分布を調べたところ、結果はそれぞれ第１図に
示すとおりであつた。
Growth rate 2.5 mm/min Average deposition rate 30.5 g/hr Size (diameter) 70.2 mm Weight 110 g Apparent density 0.09 g/cm 3 Each deposited glass obtained using distance (1), (2), or (3) above The soot was placed in a furnace at 1,600°C and was melted and made transparent while passing He gas through it. These glass base materials were cut into rounds with a thickness of 5 cm, and after polishing and cleaning one side, the concentration distribution of GeO 2 was examined using an X-ray microanalyzer manufactured by Shimadzu Corporation, and the results were as shown in Figure 1. .
これらの結果から本発明の目的を達成するため
には前記距離を50mm以上にすることが重要である
ことがわかる。 These results show that it is important to set the distance to 50 mm or more in order to achieve the object of the present invention.
実施例 ２
実施例１において、距離を50mmから70mm、90
mm、120mmと大きくしたほかは同様にしてガラス
微粒子を堆積させ、透明ガラス母材を得てGeO2
の濃度分布を調べた。結果は第２図に示すとおり
であり、距離の増加と共にクラツド層は厚くなる
が、GeO2濃度が低くなり、コア層とクラツド層
との屈折率差は小さくなる。Example 2 In Example 1, the distance was changed from 50 mm to 70 mm and 90 mm.
Glass particles were deposited in the same manner except that the size was increased to 120 mm and 120 mm to obtain a transparent glass base material and GeO 2
We investigated the concentration distribution of The results are shown in FIG. 2. As the distance increases, the cladding layer becomes thicker, but the GeO 2 concentration decreases and the difference in refractive index between the core layer and the cladding layer becomes smaller.
第２図においてそれぞれの曲線についてｒ（母
材径）とａ（実効コア径）の比を調べると下記の
とおりである。曲線No.
距 離 ａ／ｒ
(4) 50mm 0.56
(5) 70mm 0.42
(6) 90mm 0.28
(7) 120mm 0.19
以上の結果から、実効コア径は母材径に対して
0.15〜0.60の範囲が適当である。 The ratio of r (base material diameter) to a (effective core diameter) for each curve in FIG. 2 is examined as follows. Curve No. Distance a/r (4) 50mm 0.56 (5) 70mm 0.42 (6) 90mm 0.28 (7) 120mm 0.19 From the above results, the effective core diameter is relative to the base material diameter.
A range of 0.15 to 0.60 is appropriate.
実施例 ３
実施例１において、原料ガスとしてPOCl3を使
用せず、同条件でパブリングさせたSiCl4とGeCl4
との均一混合ガスを使用したほかは同様の操作で
円柱状のガラススートを製造した。ただしこの場
合にバーナ出口端面とガラス微粒子堆積面との距
離を80mmとして堆積生長させた。得られたガラス
スートは62mmφ、生長速度28.2ｇ／hr、重さ110
ｇであつた。これをCl20.2モル％含むHeガス中
で1600℃に加熱して脱水処理、溶融透明化した。
このようにして得たガラス母材は第３図Ａに示す
とおりの屈折率プロフアイルであり、クラツド層
はコア径の2.45倍すなわちクラツド径に対する実
効コア径比0.29であつた。Example 3 In Example 1, SiCl 4 and GeCl 4 were bubbled under the same conditions without using POCl 3 as the raw material gas.
A cylindrical glass soot was produced in the same manner except that a homogeneous gas mixture was used. However, in this case, the distance between the end face of the burner outlet and the surface on which glass fine particles were deposited was set to 80 mm for deposition growth. The obtained glass soot had a diameter of 62 mm, a growth rate of 28.2 g/hr, and a weight of 110
It was hot at g. This was heated to 1600° C. in He gas containing 0.2 mol% of Cl 2 to dehydrate it and melt it to make it transparent.
The glass base material thus obtained had a refractive index profile as shown in FIG. 3A, and the cladding layer was 2.45 times the core diameter, that is, the ratio of the effective core diameter to the cladding diameter was 0.29.
なお、２本のバーナを使用する従来の方法すな
わち１本のバーナでコア層を形成し次に他のバー
ナでクラツド層を形成することにより製造したガ
ラス母材の屈折率プロフアイルは第３図Ｂに、ま
た２本のバーナを使用する点では第３図Ｂの場合
と同じであるができるだけイレギユラーが少なく
なるように細心の注意を払つて製造したガラス母
材の屈折率プロフアイルは第３図Ｃにそれぞれ示
すとおりであつた。 The refractive index profile of the glass base material manufactured by the conventional method using two burners, that is, by forming the core layer with one burner and then forming the cladding layer with the other burner, is shown in Figure 3. The refractive index profile of the glass base material is the same as in Figure 3B in that two burners are used, but the refractive index profile of the glass base material is manufactured with great care to minimize irregularities as much as possible. They were as shown in Figure C.
他方シングルモード光フアイバを作るために、
第３図Ａのガラス母材に外付けCVD法によりガ
ラス微粒子を堆積し、1600℃で脱水処理、溶融透
明化を行つて、実効コア径の8.8倍のインゴツト
を作り、さらにこのものにヘラウス社のスプラジ
ルWG管をジヤケツトし、プリフオームを製造し
た。これを2000℃の線引炉を用いて外径125μに
線引し、シリコーン樹脂をコーテイングして光フ
アイバを得た。この光フアイバの伝送特性は下記
のとおりであり低い損失を示した。 On the other hand, to make a single mode optical fiber,
Fine glass particles are deposited on the glass base material shown in Figure 3A by the external CVD method, dehydrated at 1600℃, and melted and made transparent to create an ingot with an effective core diameter of 8.8 times. A preform was manufactured by jacketing the Spradil WG tube. This was drawn to an outer diameter of 125μ using a drawing furnace at 2000°C and coated with silicone resin to obtain an optical fiber. The transmission characteristics of this optical fiber are as follows, and it showed low loss.
実質屈折率差：0.268％ 伝送損失 ：0.33dB／Km（1.3μｍ） 伝送損失 ：0.16dB／Km（1.55μｍ） Actual refractive index difference: 0.268% Transmission loss: 0.33dB/Km (1.3μm) Transmission loss: 0.16dB/Km (1.55μm)
第１図、第２図および第３図はそれぞれ実施例
１、実施例２および実施例３の結果を示したもの
である。
FIG. 1, FIG. 2, and FIG. 3 show the results of Example 1, Example 2, and Example 3, respectively.
Claims (1)
素炎の中に、ガラス形成原料化合物とドープ剤と
からなる均一組成の原料ガスを該バーナの一本の
中心ノズルから噴出せしめて火炎加水分解し、バ
ーナ出口端面と堆積面との距離を50mm以上に維持
しながら、該火炎加水分解で形成されるガラス微
粒子を回転しているターゲツトの先端に吹き付け
軸方向に堆積生長させることにより、ドープ剤を
含むコアスート層とドープ剤を実質的に含まない
クラツドスート層とを同時に形成し、溶融透明化
することを特徴とする光フアイバ用ガラス母材の
製造方法。1 A raw material gas with a uniform composition consisting of a glass-forming raw material compound and a dopant is ejected from one central nozzle of the burner into an oxyhydrogen flame formed by a single concentric multi-tube burner to perform flame hydrolysis. Then, while maintaining the distance between the burner outlet end face and the deposition surface at 50 mm or more, the glass particles formed by the flame hydrolysis are sprayed onto the tip of the rotating target and deposited and grown in the axial direction. 1. A method for producing a glass preform for an optical fiber, comprising simultaneously forming a core soot layer containing a dopant and a clad soot layer substantially free of a dopant, and melting and making the preform transparent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15968984A JPS6136133A (en) | 1984-07-30 | 1984-07-30 | Manufacture of glass preform for optical fiber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15968984A JPS6136133A (en) | 1984-07-30 | 1984-07-30 | Manufacture of glass preform for optical fiber |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6136133A JPS6136133A (en) | 1986-02-20 |
| JPH0154288B2 true JPH0154288B2 (en) | 1989-11-17 |
Family
ID=15699166
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15968984A Granted JPS6136133A (en) | 1984-07-30 | 1984-07-30 | Manufacture of glass preform for optical fiber |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6136133A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0776108B2 (en) * | 1986-05-12 | 1995-08-16 | 住友電気工業株式会社 | Method for manufacturing base material for optical fiber |
-
1984
- 1984-07-30 JP JP15968984A patent/JPS6136133A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6136133A (en) | 1986-02-20 |
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