JP2003206153A - Optical fiber preform, method for manufacturing the same, and method for manufacturing optical fiber - Google Patents
Optical fiber preform, method for manufacturing the same, and method for manufacturing optical fiberInfo
- Publication number
- JP2003206153A JP2003206153A JP2002001812A JP2002001812A JP2003206153A JP 2003206153 A JP2003206153 A JP 2003206153A JP 2002001812 A JP2002001812 A JP 2002001812A JP 2002001812 A JP2002001812 A JP 2002001812A JP 2003206153 A JP2003206153 A JP 2003206153A
- Authority
- JP
- Japan
- Prior art keywords
- optical fiber
- glass
- fiber preform
- glass rod
- base 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.)
- Granted
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]
- C03B37/01413—Reactant delivery systems
- C03B37/0142—Reactant deposition burners
-
- 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
-
- 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
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
【発明の詳細な説明】Detailed Description of the Invention
【0001】[0001]
【発明の属する技術分野】本発明は、光通信などに用い
られる光ファイバの製造に有用な光ファイバ母材とその
光ファイバ母材の製造方法およびその母材から光ファイ
バを製造する方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber preform useful for producing an optical fiber used for optical communication, a method for producing the optical fiber preform, and a method for producing an optical fiber from the preform.
【0002】[0002]
【従来の技術】従来の光ファイバの製造方法として、光
ファイバ化後にコアとなる部分を含むガラスロッドの外
周に原料ガスの火炎加水分解によりガラス微粒子を堆積
させて複合母材を形成し、その後堆積したガラス微粒子
を脱水焼結(ガラス化)することにより光ファイバ母材
を製造し、その光ファイバ母材の一端を加熱溶融して線
引きし、一定外径の光ファイバとする方法が一般に知ら
れている。2. Description of the Related Art As a conventional method for producing an optical fiber, glass microparticles are deposited by flame hydrolysis of a raw material gas on the outer periphery of a glass rod including a portion to be a core after the optical fiber is formed, and then a composite base material is formed. It is generally known that an optical fiber preform is manufactured by dehydration sintering (vitrification) of the deposited glass particles, and one end of the optical fiber preform is heated and melted and drawn to form an optical fiber with a constant outer diameter. Has been.
【0003】ここで、光ファイバ母材を製造する方法に
ついて見ると、例えば、本出願人の提案した特開平10
−7430号公報に開示された方法がある。この方法
は、ガラスロッドを回転させながら複数のガラス微粒子
発生装置(バーナ)をガラスロッドの長手方向に移動さ
せることにより、ガラスロッドの外周にガラス微粒子を
堆積させる技術に関するものである。このような技術に
より製造される複合母材には、図4に示されるように一
般に良質な光ファイバとなる外径一定部と、その両端に
外径が端部に向かって徐々に小さくなるテーパ部とが形
成されるが、このテーパ部は図に示されるように両端が
ほぼ同一傾斜である。また、このようにして得られた複
合母材を脱水焼結して光ファイバ母材とする工程におい
ては、複合母材を加熱炉内に鉛直方向につり下げて、回
転させながらゆっくり引き下げを行うことで処理するの
が一般的である。そして、脱水焼結して得られた光ファ
イバ母材は線引き炉に導入されてその下部を加熱溶融さ
れ、線引きされ光ファイバとなる。Now, looking at a method for manufacturing an optical fiber preform, for example, Japanese Patent Application Laid-Open No. 10-242242 proposed by the present applicant.
There is a method disclosed in Japanese Patent Laid-Open No. 7430. This method relates to a technique of depositing glass particles on the outer circumference of a glass rod by moving a plurality of glass particle generating devices (burners) in the longitudinal direction of the glass rod while rotating the glass rod. As shown in FIG. 4, a composite preform manufactured by such a technique has a constant outer diameter portion which generally becomes a good quality optical fiber, and a taper at which the outer diameter is gradually reduced toward both ends. The tapered portion has substantially the same inclination at both ends as shown in the figure. Further, in the step of dehydrating and sintering the composite preform thus obtained into the optical fiber preform, the composite preform is suspended vertically in the heating furnace and slowly pulled down while rotating. It is common to process by this. Then, the optical fiber preform obtained by dehydration sintering is introduced into a drawing furnace, the lower portion thereof is heated and melted, and drawn into an optical fiber.
【0004】[0004]
【発明が解決しようとする課題】ところで、近年は、光
ファイバ需要の拡大によって製造の効率化およびコスト
ダウンを目的として、光ファイバ母材を大型化する傾向
があり、この光ファイバ母材の大型化に伴い、脱水焼結
工程および線引き工程において種々の問題点が明らかに
なってきた。まず、脱水焼結(ガラス化)工程における
問題点として、複合母材のつり下げ部分に非常に大きな
荷重が加わっており、つり下げ部分に焼結時の高温度が
加わると軟化して母材が変形することが挙げられる。例
えば、図5に従って説明すると、良好な光ファイバ母材
を十分に取ろうとして、テーパ部も含めガラス微粒子堆
積部分を全てガラス化すると、ガラスロッド1が延びて
図5(a)に示すように母材が落下することになる。し
たがって、これを回避するために、複合母材を脱水焼結
して光ファイバ母材を得る際には、つり下げ部分に焼結
時の高温度が加わらないように、つり下げ部分側のテー
パ部の一部にガラス微粒子が完全に焼結されない部分
(非焼結部)を適度に残しておく必要がある。それは、
非焼結部が断熱材としての役割を果たし、つり下げ部分
の軟化変形を抑制する効果をもつからである。By the way, in recent years, there has been a tendency to increase the size of the optical fiber preform for the purpose of manufacturing efficiency and cost reduction due to the expansion of the demand for the optical fiber. As a result, various problems have become clear in the dehydration sintering process and the drawing process. First of all, as a problem in the dehydration sintering (vitrification) process, a very large load is applied to the suspended part of the composite base material, and when the high temperature during sintering is applied to the suspended part, it softens and becomes a base material. Can be deformed. For example, referring to FIG. 5, if the glass particle deposition portion including the tapered portion is entirely vitrified in an attempt to sufficiently obtain a good optical fiber preform, the glass rod 1 extends and as shown in FIG. The base material will fall. Therefore, in order to avoid this, when the composite preform is dehydrated and sintered to obtain the optical fiber preform, the taper on the side of the hanging part is kept so that the high temperature during sintering is not applied to the hanging part. It is necessary to appropriately leave a portion (non-sintered portion) where the glass fine particles are not completely sintered in a part of the portion. that is,
This is because the non-sintered portion functions as a heat insulating material and has an effect of suppressing softening deformation of the suspended portion.
【0005】次に、脱水焼結工程および線引き工程にお
ける問題点として、良質の光ファイバを効率よく取ろう
として、図6に示すように複合母材の外径一定部を多く
しテーパ部の傾斜を急にしてテーパ部の長さを短くした
場合でも、その効果が表れないことが挙げられる。例え
ば、テーパ部の傾斜および長さが複合母材の両端でほぼ
同じである傾斜(図6)では、未焼結部を適度に残し、
図5(a)に示すような母材の変形を防止しようとする
と、図5(b)に示すように外径一定部の外径に対して
未焼結部の外径が大幅に大きくなり、この母材をこのま
ま線引きすると、線引き炉心管の入口あるいは管内壁面
にぶつかり、最後まで効率よく線引きすることができな
いものとなる。したがって、未焼結部を形成する側のテ
ーパ部の傾斜を急にして長さを短くし、外径一定部を多
くすることには限界がある。また、線引き工程における
問題点として、良品を効率よく取ろうとしてテーパ部の
傾斜を急にして長さを短くするために、脱水焼結工程と
線引き工程との間に別の工程を必要とすることが挙げら
れる。例えば、脱水焼結後の光ファイバ母材の線引き開
始側の端部を、線引きに最適な傾斜に加工することが一
般的に行われており、具体的には、光ファイバ母材を延
伸したり、切り割ったりして線引きに最適な形状を作っ
ている。しかし、この方法では、設備や多くの労力や時
間を要し、また、光ファイバ母材にこの加工を施すと、
良品部のロスも多くなり、甚だ効率が良くないものであ
る。Next, as a problem in the dehydration sintering process and the drawing process, in order to efficiently obtain a good quality optical fiber, as shown in FIG. 6, the outer diameter constant portion of the composite base material is increased and the taper portion is inclined. Even if the taper portion is suddenly shortened to shorten the length, the effect may not be exhibited. For example, in the inclination (FIG. 6) in which the inclination and the length of the tapered portion are substantially the same at both ends of the composite base material, the unsintered portion is appropriately left,
If it is attempted to prevent the deformation of the base material as shown in FIG. 5 (a), the outer diameter of the unsintered portion becomes significantly larger than the outer diameter of the constant outer diameter portion as shown in FIG. 5 (b). If this base material is drawn as it is, it will hit the inlet of the drawn core tube or the inner wall surface of the tube, and it will not be possible to draw efficiently until the end. Therefore, there is a limit to making the taper portion on the side forming the unsintered portion steep so as to shorten its length and increase the outer diameter constant portion. Further, as a problem in the drawing process, another process is required between the dehydration and sintering process and the drawing process in order to steeply incline the taper portion and shorten the length in order to efficiently obtain a good product. It can be mentioned. For example, it is generally performed to process the end portion of the optical fiber preform after the dehydration sintering on the drawing start side into an inclination that is most suitable for drawing. Specifically, the optical fiber preform is stretched. The best shape for drawing is made by cutting or cutting. However, this method requires equipment and a lot of labor and time, and when the optical fiber preform is subjected to this processing,
There is also a lot of loss in the non-defective part, which is very inefficient.
【0006】ここで、光ファイバ母材のテーパ部の傾斜
を規定したものが、例えば特開平9−100132号公
報、特開2000−264662公報に開示されてい
る。しかし、特開平9−100132号公報に開示され
たテーパ部は、ガラスロッドと同一の径まで小さくなっ
ていない。また、例示されたテーパ部は、かりにガラス
ロッドと同一の径まで小さくなっていたとしても、テー
パ部は線引き開始部が線引き終了部より長くなってしま
う。また、この公報に示されるテーパ部はあくまでも均
質な光ファイバの一部として利用することを想定してお
り、ガラス特性の長手変動を低減させることが目的であ
り、本発明の解決すべき課題とは関連がない。また、特
開2000−264662公報に開示されたテーパ部
は、ファイバ母材を加熱加工により所定の傾斜とされる
が、加熱加工を行う前のテーパ部の傾斜については言及
されておらず不明である。さらに、加熱加工を行うこと
を実質的に必須の要件としており、工程が追加されるこ
とによる生産性の低下をもたらすことは前述のとおりで
ある。そこで、本発明では、複合母材が変形することな
く焼結でき且つファイバ化の有効部を多く得ることが可
能な光ファイバ母材の製造方法とその得られる光ファイ
バ母材並びにその光ファイバ母材から簡略化した工程で
光ファイバを線引き製造する方法を提供することを目的
とする。Here, those in which the inclination of the taper portion of the optical fiber preform is defined are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 9-100132 and 2000-264662. However, the tapered portion disclosed in Japanese Patent Application Laid-Open No. 9-100132 is not reduced to the same diameter as the glass rod. Further, even if the taper portion illustrated is reduced to the same diameter as the glass rod, the drawing start portion of the taper portion is longer than the drawing end portion. Further, the tapered portion shown in this publication is assumed to be used as a part of a homogeneous optical fiber to the last, and the purpose is to reduce the longitudinal fluctuation of the glass characteristics, and the problems to be solved by the present invention. Is not relevant. Further, the taper portion disclosed in Japanese Patent Laid-Open No. 2000-264662 is made to have a predetermined inclination by heating the fiber preform, but the inclination of the taper portion before the heat processing is not mentioned because it is not mentioned. is there. Furthermore, it is essentially an essential requirement to perform heat processing, and as described above, the addition of steps causes a decrease in productivity. Therefore, in the present invention, a method for producing an optical fiber preform capable of sintering the composite preform without deformation and obtaining a large number of effective parts for fiberization, the obtained optical fiber preform, and the optical fiber preform. An object of the present invention is to provide a method for drawing and manufacturing an optical fiber from a material by a simplified process.
【0007】[0007]
【課題を解決するための手段】本発明者は上記課題に鑑
み鋭意研究した結果、光ファイバ母材の両端部に形成さ
れるテーパ部の傾斜を異なるものにするのが良いことが
判明し、本発明に至った。すなわち、本発明は、(1)
光ファイバ化後にコアとなる部分を含むガラスロッドの
外周にガラス微粒子を堆積させて複合母材を形成し、前
記複合母材を脱水焼結することにより得られる光ファイ
バ母材であって、前記脱水焼結後の光ファイバ母材の両
端部に形成されているテーパ部の傾斜が異なっているこ
とを特徴とする光ファイバ母材、(2)光ファイバ化後
にコアとなる部分を含むガラスロッドを形成する第1工
程、該ガラスロッドをその軸を中心に回転させながらガ
ラス微粒子発生装置を前記ガラスロッドの長手方向に相
対的に往復移動させることにより前記ガラスロッドの外
周にガラス微粒子を堆積させて複合母材を形成する第2
工程、前記複合母材を加熱炉内にほぼ鉛直に支持しなが
ら回転させて脱水焼結して光ファイバ母材を得る第3工
程を有する光ファイバ母材の製造方法であって、前記第
2工程が複合母材の両端部に形成されるテーパ部の傾斜
が異なるように前記ガラスロッドの外周にガラス微粒子
を堆積させることを特徴とする光ファイバ母材の製造方
法、(3)前記第2工程のガラス微粒子発生装置の前記
ガラスロッドの長手方向への相対移動速度を、前記往復
移動の一方の折り返し点付近で徐々に上昇させることを
特徴とする(2)に記載の光ファイバ母材の製造方法、
(4)前記第2工程のガラス微粒子発生装置に供給され
るガラス微粒子原料の供給量を、前記往復移動の一方の
折り返し点付近で徐々に減少させることを特徴とする
(2)に記載の光ファイバ母材の製造方法、(5)前記
第2工程のガラス微粒子発生装置は複数使用し、複数の
ガラス微粒子発生装置の往復移動の振幅をそれぞれで異
ならせ、かつ前記往復移動の周期をそれぞれほぼ等しく
することを特徴とする(2)に記載の光ファイバ母材の
製造方法、(6)前記第3工程は、前記複合母材両端部
に形成される前記テーパ部のうち、傾斜が急な側のテー
パ部を下向きにして複合母材を脱水焼結することを特徴
とする(2)記載の光ファイバ母材の製造方法、およ
び、(7)光ファイバ化後にコアとなる部分を含むガラ
スロッドを形成する第1工程、該ガラスロッドをその軸
を中心に回転させながらガラス微粒子発生装置を前記ガ
ラスロッドの長手方向に相対的に往復移動させることに
より前記ガラスロッドの外周にガラス微粒子を堆積させ
て複合母材を形成する第2工程、前記複合母材を加熱炉
内にほぼ鉛直に支持しながら回転させて脱水焼結して光
ファイバ母材を得る第3工程および前記光ファイバ母材
の脱水焼結の際に下向きとなった側の端部の形状を実質
的に維持したまま前記光ファイバ母材を線引き炉に導入
して線引きする第4工程を有することを特徴とする光フ
ァイバの製造方法、を提供するものである。DISCLOSURE OF THE INVENTION As a result of earnest studies in view of the above problems, the present inventor has found that it is better to make the inclinations of the taper portions formed at both ends of the optical fiber preform different. The present invention has been completed. That is, the present invention provides (1)
An optical fiber preform obtained by depositing glass fine particles on the outer periphery of a glass rod including a portion to be a core after forming an optical fiber to form a composite preform, and dehydrating and sintering the composite preform, An optical fiber preform characterized in that the taper portions formed at both ends of the optical fiber preform after dehydration sintering have different inclinations, and (2) a glass rod including a portion which becomes a core after being made into an optical fiber. In the first step of forming the glass rod, while rotating the glass rod about its axis, the glass fine particle generator is relatively reciprocated in the longitudinal direction of the glass rod to deposit glass fine particles on the outer periphery of the glass rod. Second to form a composite matrix
A method for producing an optical fiber preform having a third step of rotating the composite preform in a heating furnace while supporting the composite preform in a vertical direction to dehydrate and sinter to obtain the optical fiber preform. A step of depositing glass fine particles on the outer periphery of the glass rod so that the taper portions formed at both ends of the composite base material have different inclinations; The relative movement speed in the longitudinal direction of the glass rod of the glass fine particle generator in the step is gradually increased in the vicinity of one turning point of the reciprocating movement. Production method,
(4) The light according to (2), wherein the supply amount of the glass fine particle raw material supplied to the glass fine particle generating device in the second step is gradually reduced in the vicinity of one turning point of the reciprocating movement. (5) A plurality of glass fine particle generators in the second step are used, the reciprocating movement amplitudes of the plurality of glass fine particle producing apparatuses are made different, and the cycle of the reciprocating movements is substantially the same. (2) The method for manufacturing an optical fiber preform according to (2), characterized in that the inclination is steep among the taper portions formed at both ends of the composite preform. (2) The method for producing an optical fiber preform according to (2), wherein the composite preform is dehydrated and sintered with the taper portion on the side facing downward, and (7) a glass including a portion to be a core after being made into an optical fiber. Forming rod Step: While rotating the glass rod about its axis, the glass fine particle generator is relatively reciprocated in the longitudinal direction of the glass rod to deposit glass fine particles on the outer periphery of the glass rod to form a composite base material. A second step of forming, a third step of rotating the composite preform in a heating furnace while supporting it substantially vertically and performing dehydration sintering to obtain an optical fiber preform, and a dehydration sintering of the optical fiber preform. And a fourth step of introducing the optical fiber preform into a drawing furnace and drawing the optical fiber while substantially maintaining the shape of the end on the downward side. To do.
【0008】[0008]
【発明の実施の形態】次に、本発明の好ましい実施の態
様について、添付の図面に基づいて詳細に説明する。な
お、各図の説明において同一の要素には同一の符号を付
して重複する説明を省略する。まず、第1工程は、光フ
ァイバ化後にコアとなる部分を含むガラス微粒子集合体
を例えば周知のVAD法などにより形成し、その集合体
を脱水焼結し、必要に応じて目的の外径となるように延
伸し、所望のガラスロッドを得る。その外径は30mm
〜50mm、長さ500〜2000mmが好ましい。BEST MODE FOR CARRYING OUT THE INVENTION Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of each drawing, the same elements will be denoted by the same reference symbols and redundant description will be omitted. First, in the first step, a glass fine particle aggregate including a portion to be a core after being made into an optical fiber is formed by, for example, the well-known VAD method, the aggregate is dehydrated and sintered, and if necessary, a desired outer diameter is obtained. To obtain the desired glass rod. Its outer diameter is 30 mm
-50 mm and length 500-2000 mm are preferable.
【0009】次いで、第2工程は図2(a)に示すよう
にそのガラスロッド1をその長手軸を中心に回転させな
がらその外周にガラス微粒子発生装置(バーナ)Aをガ
ラスロッド1の長手方向に相対的に往復移動させてガラ
スロッド1の外周にガラス微粒子2を堆積させて複合母
材3を得る工程である。ここで、第2工程では、複合母
材両端部に形成されるテーパ部の傾斜が異なるように前
記ガラスロッドの外周にガラス微粒子を堆積させること
が望ましい。本発明の複合母材3の形状の一例を図1
(a)に正面図として示す。図1(a)の複合母材は、
その両端のテーパ部の傾斜が異なるものであり、本発明
の光ファイバ母材の製造方法は、図1(b)に例示され
る傾斜のファイバ母材を製造するために適するものであ
る。本発明の母材のテーパ部は、その面の母線が直線だ
けでなく、図1(a)や図4に示すように曲線であって
もよい。ここで、テーパ部の傾斜S(%)は、テーパ部
の長さをL、外径一定部の外径をD、ガラスロッドの平
均外径をdとしたとき、S=L×100/{(D−d)
/2}で表される。図1(a)におけるテーパ部の傾斜
Sは、傾斜が緩やかな側(上部)のテーパ部で約150
〜350%の範囲が好ましく、さらに好ましくは約20
0〜300%であり、傾斜が急な側(下部)のテーパ部
は約50〜150%の範囲が好ましく、さらに好ましく
は約70〜120%である。図1(b)は、図1(a)
の複合母材を脱水焼結した場合の本発明の光ファイバ母
材の形状の一例を示す正面図である。図1(b)におけ
るテーパ部の傾斜Sは、傾斜が緩やかな側のテーパ部で
約200〜600%の範囲が好ましく、さらに好ましく
は約350〜550%であり、傾斜が急な側のテーパ部
で約100〜300%の範囲が好ましく、さらに好まし
いのは約130〜250%である。また、未焼結部の外
径は焼結後の外径一定部の外径の約95〜120%の範
囲が好ましい。Next, in the second step, as shown in FIG. 2A, while rotating the glass rod 1 about its longitudinal axis, a glass fine particle generator (burner) A is provided on the outer periphery of the glass rod 1 in the longitudinal direction of the glass rod 1. Is a step of reciprocating relatively to and depositing the glass fine particles 2 on the outer periphery of the glass rod 1 to obtain the composite base material 3. Here, in the second step, it is desirable to deposit glass particles on the outer circumference of the glass rod so that the tapered portions formed at both ends of the composite base material have different inclinations. FIG. 1 shows an example of the shape of the composite base material 3 of the present invention.
It is shown as a front view in (a). The composite base material of FIG. 1 (a) is
The taper portions at both ends have different inclinations, and the method for producing an optical fiber preform of the present invention is suitable for producing the inclined fiber preform illustrated in FIG. 1 (b). In the tapered portion of the base material of the present invention, the generatrix of the surface is not limited to a straight line, but may be a curved line as shown in FIG. Here, the slope S (%) of the taper portion is S = L × 100 / {, where L is the length of the taper portion, D is the outer diameter of the constant outer diameter portion, and d is the average outer diameter of the glass rod. (D-d)
/ 2}. The inclination S of the taper portion in FIG. 1A is about 150 at the taper portion on the side where the inclination is gentle (upper part).
Is preferably in the range of ~ 350%, more preferably about 20.
0 to 300%, and the taper portion on the steep slope (lower part) is preferably about 50 to 150%, more preferably about 70 to 120%. FIG. 1B is the same as FIG.
FIG. 3 is a front view showing an example of the shape of the optical fiber preform of the present invention when the composite preform of FIG. The slope S of the taper portion in FIG. 1B is preferably about 200 to 600%, more preferably about 350 to 550% in the taper portion on the side where the slope is gentle, and the taper on the side where the slope is steep. A range of about 100-300% by weight is preferred, and more preferably about 130-250%. Further, the outer diameter of the unsintered portion is preferably within a range of about 95 to 120% of the outer diameter of the constant outer diameter portion after sintering.
【0010】本発明のテーパ部の傾斜が異なる光ファイ
バ母材の製造方法の例を図2にしたがって説明する。ま
ず、ガラス微粒子発生装置の移動速度を変更することに
よる方法である。例えば光ファイバ化後にコアとなる部
分を含むガラスロッドをその長手軸を中心に回転させな
がらその外周にガラス微粒子を堆積させて複合母材を製
造するものであるが、ガラス微粒子発生装置を長手軸方
向(上下方向)に往復移動させる場合の複合母材製造中
のガラスロッド1とガラス微粒子発生装置(バーナ)A
との位置関係を図2(a)に示す。図2(a)の位置関
係に配置されたガラス微粒子発生装置(バーナ)Aの移
動速度の様子を図2(b)にグラフで示す。図2(b)
において、縦軸のバーナの位置は図2(a)のバーナ位
置に相当するものであり、点線は折り返し点を示し、横
軸はその位置でのバーナの速度を表す。原料ガス及び燃
料ガス等の供給条件を同じにしてガラス微粒子発生装置
を定速度で移動させた後、往復移動の一方(図では上
方)の折り返し点付近(点P)で徐々に移動速度を上昇
し、折り返し後はP点までは徐々に速度を下降し、以後
定速で移動させる。移動速度はガス供給量やガラスロッ
ドの長さ等に応じて適宜定まるが、定速度は約20〜5
0mm/秒の範囲内に設定するのが好ましく、速度上昇
後の最大速度は約100〜300mm/秒程度が好まし
い。したがって、移動速度が上昇する位置においては、
母材の単位面当たりのガラス微粒子の付着量が減少する
ため、図1(a)に示すような両端部に形成されるテー
パ部の傾斜が異なる複合母材を容易に得ることができ
る。テーパ部の終了端は図示のようにバーナの折り返し
点(点線位置)より外側となる。ここでは、ガラス微粒
子発生装置の移動について述べたが、ガラス微粒子発生
装置を定位置に固定し、ガラスロッドを移動させて同様
の操作を行っても良いのは勿論である。次に、ガラス微
粒子発生装置への原料ガス供給量を変更することによる
方法を示す。図2(c)はガラス微粒子発生装置の位置
と原料ガス供給量の関係を示すグラフの一例である。図
2(c)において、縦軸のバーナの位置は図2(a)の
バーナ位置に相当するものであり、横軸はその位置での
バーナからの原料ガス供給量を表す。相対移動速度を一
定にして原料ガス供給量を図2(c)に示すように往復
移動の一方の折り返し点付近(点P)で徐々に減少させ
るようにしても、折り返し点付近で徐々に母材の単位面
当たりのガラス微粒子の付着量が減少するため、同様に
図1(a)に示すような複合母材が得られる。さらに、
図2(b)と図2(c)とを組み合わせた、移動速度と
原料供給量をともに制御する方法をガラス微粒子発生装
置に対して行っても同様にテーパ部の傾斜が異なる複合
母材が得られることはいうまでもない。An example of a method for manufacturing an optical fiber preform having different tapered portions according to the present invention will be described with reference to FIG. First, there is a method by changing the moving speed of the glass particle generator. For example, a glass rod including a portion to be a core after being made into an optical fiber is rotated around its longitudinal axis to deposit glass particles on its outer periphery to manufacture a composite preform. Glass rod 1 and glass fine particle generator (burner) A during the manufacture of the composite base material when reciprocating in the vertical direction (vertical direction)
The positional relationship between and is shown in FIG. The state of the moving speed of the glass particle generator (burner) A arranged in the positional relationship of FIG. 2 (a) is shown in the graph of FIG. 2 (b). Figure 2 (b)
2A, the burner position on the vertical axis corresponds to the burner position in FIG. 2A, the dotted line indicates the turning point, and the horizontal axis indicates the speed of the burner at that position. After moving the glass particle generator at a constant speed under the same supply conditions of the raw material gas and the fuel gas, the moving speed is gradually increased near the turning point (point P) of one of the reciprocating movements (upper in the figure). Then, after turning back, the speed is gradually decreased to the point P, and thereafter, it is moved at a constant speed. The moving speed is appropriately determined according to the gas supply amount, the length of the glass rod, etc., but the constant speed is about 20 to 5
It is preferable to set it within the range of 0 mm / sec, and the maximum velocity after velocity increase is preferably about 100 to 300 mm / sec. Therefore, at the position where the moving speed increases,
Since the adhesion amount of the glass fine particles per unit surface of the base material is reduced, it is possible to easily obtain a composite base material in which the taper portions formed at both ends have different slopes as shown in FIG. The end of the tapered portion is outside the turning point (dotted line position) of the burner as shown in the figure. Here, the movement of the glass particle generator is described, but it goes without saying that the same operation may be performed by fixing the glass particle generator at a fixed position and moving the glass rod. Next, a method by changing the amount of raw material gas supplied to the glass particle generator will be described. FIG. 2C is an example of a graph showing the relationship between the position of the glass fine particle generator and the supply amount of the raw material gas. In FIG. 2 (c), the burner position on the vertical axis corresponds to the burner position in FIG. 2 (a), and the horizontal axis represents the source gas supply amount from the burner at that position. Even if the relative movement speed is kept constant and the raw material gas supply amount is gradually decreased near one turning point (point P) of the reciprocating movement as shown in FIG. Since the adhered amount of glass fine particles per unit surface of the material is reduced, a composite base material as shown in FIG. 1A is also obtained. further,
Even when the method for controlling both the moving speed and the raw material supply amount, which is a combination of FIG. 2B and FIG. 2C, is applied to the glass particle generating apparatus, a composite base material having different taper inclinations is obtained. Needless to say, it can be obtained.
【0011】さらに、本発明の両端部に形成されるテー
パ部の傾斜が異なる光ファイバ母材の製造方法の他の一
例を図3に示す。図3(a)は、複数のガラス微粒子発
生装置(バーナ)を上下方向に往復移動させてガラスロ
ッドの外周にガラス微粒子を堆積させるものであり、複
数のガラス微粒子発生装置(この場合は3本)は、お互
いに接触しないように配置されており独立して往復移動
を行うものである。この方法はガラス微粒子発生装置の
往復移動について、その振幅をそれぞのガラス微粒子発
生装置(バーナ)で異ならせながら周期をほぼ等しくす
るものである。図3(b)及び(c)は、それぞれのガ
ラス微粒子発生装置(バーナ)の振幅即ち移動範囲を図
3(a)に対応させて表示するものである。形成される
テーパ部の傾斜が異なるようにするならばその振幅はど
のような範囲でも適宜設定できるが、例えば、図3
(a)に示すように上部折り返し位置では、それぞれの
バーナ折り返し位置は、150mmずつずらすのが好ま
しく、下部折り返し位置では、50mmずつずらすのが
好ましい。図3(c)の場合は、3本のバーナの移動範
囲の差を小さくしたパターンである。いずれの場合で
も、バーナは一往復の時間が同じになるようにその速度
は異なる設定となっている。このように複数のガラス微
粒子発生装置のそれぞれの振幅を変えることにより、図
1(a)に示すような両端部のテーパ部の傾斜が異なる
複合母材を容易に得ることができる。そして、それぞれ
のバーナ折り返し位置を適宜ずらすことで、テーパ傾斜
を容易に調節することもできる。なお、この場合には、
ガラス微粒子発生装置への原料ガス供給量は、適宜調整
してよく、図2(c)に相当するような折り返し点付近
で供給量を減少させるといった供給量調整を行ってもよ
い。FIG. 3 shows another example of the method for manufacturing the optical fiber preform in which the taper portions formed at both ends of the present invention have different inclinations. FIG. 3A shows a structure in which a plurality of glass particle generators (burners) are vertically reciprocally moved to deposit glass particles on the outer periphery of a glass rod. ) Are arranged so that they do not contact each other, and independently reciprocate. In this method, the reciprocating movement of the glass particle generating device is made to have substantially the same period while varying the amplitude of each glass particle generating device (burner). FIGS. 3B and 3C show the amplitude, that is, the moving range of each glass particle generator (burner) in correspondence with FIG. 3A. If the inclinations of the formed taper portions are made different, the amplitude can be appropriately set in any range.
As shown in (a), it is preferable to shift the burner folding positions by 150 mm at the upper folding position, and preferably shift by 50 mm at the lower folding position. In the case of FIG. 3C, the difference in the moving range of the three burners is small. In either case, the burners are set to different speeds so that one round trip has the same time. By changing the amplitude of each of the plurality of glass fine particle generators in this manner, it is possible to easily obtain a composite base material in which the taper portions at both ends have different inclinations as shown in FIG. The taper inclination can be easily adjusted by appropriately shifting the respective burner folding positions. In this case,
The supply amount of the raw material gas to the glass particle generation device may be appropriately adjusted, and the supply amount may be adjusted by reducing the supply amount in the vicinity of the turning point as shown in FIG.
【0012】このようにして効率よく図1(a)に示す
ような複合母材を得ることがでる。そして、第3工程と
して、この複合母材の傾斜が急な側のテーパ部を下にし
て加熱炉内にほぼ垂直に支持しながら回転させ、ヘリウ
ムガス、塩素ガス等を送りながら約1100℃以上で脱
水を行い、さらに1400℃〜1600℃の高温で焼結
を行い、図1(b)に示すような上部に未焼結部5を少
し残した光ファイバ母材4を製造する。複合母材の上方
の支持部側はテーパが長いので支持部付近のガラスロッ
ドが高温に曝されず軟化変形の恐れがなく、焼結処理操
作が容易である。続いて、第4工程として、得られた光
ファイバ母材に望むなら適宜の処理を加えてもよいが、
さらに形状が変化するような特別な処理や加工を施すこ
となく、そのまま線引き炉へ導入し線引きを行うことが
できる。そして、伝送損失の少ない良好で均質な光ファ
イバを得ることができる。この結果従来の光ファイバの
製造方法と比較して、光ファイバ母材製造後線引きまで
に光ファイバ母材を加熱加工する工程を必要としないた
め工程が数時間短縮し、得られる光ファイバの良品率が
約10〜20%増加した。なお、本発明の実施の形態は
上述のものに限られず、特許請求の範囲に記載された発
明の範囲内で種々の変更が可能である。Thus, the composite base material as shown in FIG. 1 (a) can be efficiently obtained. Then, in the third step, the composite base material is rotated with the taper portion on the steep slope side facing downward in the heating furnace while being supported substantially vertically, and while feeding helium gas, chlorine gas, etc., about 1100 ° C. or higher. Then, it is dehydrated and further sintered at a high temperature of 1400 ° C. to 1600 ° C. to manufacture an optical fiber preform 4 with a small amount of unsintered portion 5 left on the upper portion as shown in FIG. Since the upper support portion side of the composite base material has a long taper, the glass rod in the vicinity of the support portion is not exposed to high temperature and there is no fear of softening deformation, and the sintering process operation is easy. Then, as a fourth step, the obtained optical fiber preform may be appropriately treated if desired.
Furthermore, the wire can be introduced into the wire drawing furnace as it is without any special treatment or processing that changes the shape, and wire drawing can be performed. Then, it is possible to obtain a good and uniform optical fiber with little transmission loss. As a result, compared with the conventional optical fiber manufacturing method, the process of heating the optical fiber preform before the drawing of the optical fiber preform is not required, so the process is shortened by several hours, and the obtained optical fiber is a good product. The rate increased by about 10 to 20%. The embodiments of the present invention are not limited to those described above, and various modifications can be made within the scope of the invention described in the claims.
【0013】[0013]
【実施例】周知のVAD法によりコアとなる部分を含む
外径36mm、長さ1800mmの石英ガラスロッドを
作製した。図2(a)に示すように、このガラスロッド
を垂直に配置し、時間と共に回転数を200〜25rp
mに変化させて回転させながらバーナを上下方向に移動
させてガラス微粒子を堆積させ複合母材を製造した。バ
ーナには各ガス供給装置から水素200リットル/分、
酸素90リットル/分、四塩化ケイ素100g/分、シ
ール用にアルゴンガス1.5リットル/分を供給し、火
炎分解反応によってガラス微粒子を生成させた。図2
(b)に示すように上部折り返し点より約200mm下
方に速度変更点Pを設定した。バーナは下部折り返し点
からP点まで50mm/秒の一定速度で移動し、P点か
ら上部折り返し点までその速度を徐々に上げ、折り返し
直前には最高速度150mm/秒とした。このバーナ移
動を繰り返し、ガラス微粒子を堆積した。EXAMPLE A quartz glass rod having an outer diameter of 36 mm and a length of 1800 mm including a core portion was manufactured by the well-known VAD method. As shown in FIG. 2 (a), this glass rod is arranged vertically and the rotation speed is 200 to 25 rp with time.
The composite base material was manufactured by moving the burner in the vertical direction while changing the value to m and rotating the burner to deposit glass particles. 200 liters / min of hydrogen from each gas supply device for the burner,
90 l / min of oxygen, 100 g / min of silicon tetrachloride, and 1.5 l / min of argon gas for sealing were supplied, and glass fine particles were produced by a flame decomposition reaction. Figure 2
As shown in (b), the speed change point P was set about 200 mm below the upper turning point. The burner moved at a constant speed of 50 mm / sec from the lower turning point to the P point, gradually increased its speed from the P point to the upper turning point, and had a maximum speed of 150 mm / sec immediately before turning. This burner movement was repeated to deposit glass particles.
【0014】得られた複合母材は、外径一定部の外径が
約250mmであり、上部のテーパ部の長さが約300
mm、下部約100mmの図1(a)に示すような形状
であり、その傾斜は上部で280%、下部で93%であ
った。この複合母材を傾斜が急な側のテーパ部を下にし
て、加熱炉内に垂直に支持し回転させながら脱水焼結処
理を約15時間行った。得られた光ファイバ母材は、外
径一定部の外径が150mmであり、上部の未ガラス化
部分を含むテーパ部の最大外径は約160mmであっ
た。そして、上部のテーパ部の長さが約300mm、下
部テーパ部の長さ100mmは変わりなかった。したが
って、その傾斜は上部で約530%、下部で約180%
である。このように両端部に形成されるテーパ部の傾斜
が異なった光ファイバ母材が得られた。この光ファイバ
母材は、このまま線引き炉に投入し良好に線引きを行う
ことができた。In the obtained composite base material, the outer diameter of the constant outer diameter portion is about 250 mm, and the length of the upper tapered portion is about 300 mm.
The shape was as shown in FIG. 1 (a) having a size of 100 mm and a lower part of about 100 mm, and the inclination was 280% in the upper part and 93% in the lower part. The composite base material was subjected to dehydration sintering treatment for about 15 hours while vertically supporting and rotating the composite base material in the heating furnace with the taper portion on the steep inclination side facing downward. In the obtained optical fiber preform, the outer diameter of the constant outer diameter portion was 150 mm, and the maximum outer diameter of the taper portion including the unvitrified upper portion was about 160 mm. The length of the upper taper portion was about 300 mm, and the length of the lower taper portion was 100 mm. Therefore, the slope is about 530% at the top and about 180% at the bottom.
Is. Thus, optical fiber preforms having different inclinations of the taper portions formed at both ends were obtained. The optical fiber preform was put into the drawing furnace as it was, and the drawing could be performed satisfactorily.
【0015】[0015]
【発明の効果】以上のとおり、本発明によれば、焼結後
の光ファイバ母材は特別の処理を必要とすることなく光
ファイバの製造が可能であるので、光ファイバの製造工
程を簡略化するとともに、その製造コストを低減させる
ことができる。また、複合母材の焼結時にファイバ化に
有効な部分を多く取っても母材の軟化による変形が抑制
でき、焼結操作が容易である。As described above, according to the present invention, since the optical fiber preform after sintering can be manufactured without any special treatment, the manufacturing process of the optical fiber can be simplified. And the manufacturing cost thereof can be reduced. Further, even if a large number of portions effective for fiberizing are taken during the sintering of the composite base material, the deformation due to the softening of the base material can be suppressed, and the sintering operation is easy.
【図1】(a)は本発明の光ファイバ母材の製造過程で
得られる複合母材の正面図であり、(b)は(a)の複
合母材を脱水焼結した場合の光ファイバ母材の正面図で
ある。FIG. 1A is a front view of a composite preform obtained in a manufacturing process of an optical fiber preform of the present invention, and FIG. 1B is an optical fiber when the composite preform of FIG. 1A is dehydrated and sintered. It is a front view of a base material.
【図2】本発明の光ファイバ母材の製造方法の第2工程
の例を示す説明図であり、(a)はガラスロッドとガラ
ス微粒子発生装置(バーナ)との位置関係の状態を示す
正面図であり、(b)はバーナの位置と移動速度の関係
を示すグラフであり、(c)はバーナ位置と原料ガス供
給量の関係を示すグラフである。FIG. 2 is an explanatory view showing an example of a second step of the method for producing an optical fiber preform according to the present invention, FIG. 2 (a) is a front view showing a state of a positional relationship between a glass rod and a glass fine particle generator (burner). It is a figure, (b) is a graph which shows the position of a burner, and the relationship of moving speed, (c) is a graph which shows a burner position and the relationship of source gas supply amount.
【図3】本発明の光ファイバ母材の製造方法の第2工程
の他の例を示す説明図であり、(a)はガラスロッドと
ガラス微粒子発生装置(バーナ)との位置関係の状態を
示す正面図であり、(b)、(c)はそれぞれバーナの
移動範囲を示すものである。FIG. 3 is an explanatory view showing another example of the second step of the method for producing an optical fiber preform according to the present invention, in which (a) shows the state of the positional relationship between the glass rod and the glass particle generator (burner). It is a front view shown, and (b) and (c) show the moving range of a burner, respectively.
【図4】従来の複合母材の製造方法と得られた複合母材
の形状とを説明する概略図である。FIG. 4 is a schematic view illustrating a conventional method for manufacturing a composite base material and the shape of the obtained composite base material.
【図5】(a)は焼結時に母材つり下げ部が変形した状
態の説明図であり、(b)は従来の光ファイバ母材の形
状の例を示す説明図である。5A is an explanatory view of a state in which a base material hanging portion is deformed during sintering, and FIG. 5B is an explanatory view showing an example of a shape of a conventional optical fiber base material.
【図6】従来のテーパ部の傾斜を急にした複合母材の概
略図である。FIG. 6 is a schematic view of a conventional composite base material in which the taper portion has a steep inclination.
1 ガラスロッド 2 ガラス微粒子 3 複合母材 4 光ファイバ母材 5 未焼結部 A、B、C ガラス微粒子発生装置(バーナ) 1 glass rod 2 glass particles 3 Composite base material 4 Optical fiber base material 5 Unsintered part A, B, C Glass particle generator (burner)
Claims (7)
ガラスロッドの外周にガラス微粒子を堆積させて複合母
材を形成し、前記複合母材を脱水焼結することにより得
られる光ファイバ母材であって、前記脱水焼結後の光フ
ァイバ母材の両端部に形成されているテーパ部の傾斜が
異なっていることを特徴とする光ファイバ母材。1. An optical fiber preform obtained by depositing glass fine particles on the outer periphery of a glass rod including a portion to be a core after forming an optical fiber to form a composite preform, and dehydrating and sintering the composite preform. In the optical fiber preform, the taper portions formed at both ends of the dehydrated and sintered optical fiber preform have different inclinations.
ガラスロッドを形成する第1工程、該ガラスロッドをそ
の軸を中心に回転させながらガラス微粒子発生装置を前
記ガラスロッドの長手方向に相対的に往復移動させるこ
とにより前記ガラスロッドの外周にガラス微粒子を堆積
させて複合母材を形成する第2工程、前記複合母材を加
熱炉内にほぼ鉛直に支持しながら回転させて脱水焼結し
て光ファイバ母材を得る第3工程を有する光ファイバ母
材の製造方法であって、前記第2工程が複合母材の両端
部に形成されるテーパ部の傾斜が異なるように前記ガラ
スロッドの外周にガラス微粒子を堆積させることを特徴
とする光ファイバ母材の製造方法。2. A first step of forming a glass rod including a portion to be a core after forming an optical fiber, wherein the glass particle generating device is relatively arranged in a longitudinal direction of the glass rod while rotating the glass rod about its axis. The second step of depositing glass fine particles on the outer periphery of the glass rod by reciprocating the glass rod to form a composite base material, rotating the composite base material in a heating furnace while supporting the composite base material almost vertically, and performing dehydration sintering. A method for manufacturing an optical fiber preform having a third step of obtaining an optical fiber preform, wherein the second step is performed so that the taper portions formed at both ends of the composite preform have different inclinations. A method for manufacturing an optical fiber preform, characterized in that glass particles are deposited on the outer periphery.
前記ガラスロッドの長手方向への相対移動速度を、前記
往復移動の一方の折り返し点付近で徐々に上昇させるこ
とを特徴とする請求項2に記載の光ファイバ母材の製造
方法。3. The relative movement speed in the longitudinal direction of the glass rod of the glass fine particle generator in the second step is gradually increased near one turning point of the reciprocating movement. The method for producing an optical fiber preform according to 1.
供給されるガラス微粒子原料の供給量を、前記往復移動
の一方の折り返し点付近で徐々に減少させることを特徴
とする請求項2に記載の光ファイバ母材の製造方法。4. The glass fine particle raw material supplied to the glass fine particle generator in the second step is gradually reduced in supply amount near one turnaround point of the reciprocating movement. Manufacturing method of optical fiber preform.
複数使用し、複数のガラス微粒子発生装置の往復移動の
振幅をそれぞれで異ならせ、かつ前記往復移動の周期を
それぞれほぼ等しくすることを特徴とする請求項2に記
載の光ファイバ母材の製造方法。5. A plurality of glass fine particle generators in the second step are used, the reciprocating movement amplitudes of the plurality of glass fine particle generating apparatuses are made different, and the reciprocating movement periods are made substantially equal to each other. The method for manufacturing an optical fiber preform according to claim 2.
形成される前記テーパ部のうち、傾斜が急な側のテーパ
部を下向きにして複合母材を脱水焼結することを特徴と
する請求項2記載の光ファイバ母材の製造方法。6. The third step is to dehydrate and sinter the composite base material with the taper portion having a steep slope, of the taper portions formed at both ends of the composite base material, facing downward. The method for producing an optical fiber preform according to claim 2.
ガラスロッドを形成する第1工程、該ガラスロッドをそ
の軸を中心に回転させながらガラス微粒子発生装置を前
記ガラスロッドの長手方向に相対的に往復移動させるこ
とにより前記ガラスロッドの外周にガラス微粒子を堆積
させて複合母材を形成する第2工程、前記複合母材を加
熱炉内にほぼ鉛直に支持しながら回転させて脱水焼結し
て光ファイバ母材を得る第3工程および前記光ファイバ
母材の脱水焼結の際に下向きとなった側の端部の形状を
実質的に維持したまま前記光ファイバ母材を線引き炉に
導入して線引きする第4工程を有することを特徴とする
光ファイバの製造方法。7. A first step of forming a glass rod including a core portion after being made into an optical fiber, wherein a glass particle generating device is relatively arranged in a longitudinal direction of the glass rod while rotating the glass rod about its axis. The second step of depositing glass fine particles on the outer periphery of the glass rod by reciprocating the glass rod to form a composite base material, rotating the composite base material in a heating furnace while supporting the composite base material almost vertically, and performing dehydration sintering. In the third step of obtaining the optical fiber preform and the dehydration sintering of the optical fiber preform, the optical fiber preform is introduced into the drawing furnace while substantially maintaining the shape of the end on the side facing downward. And a fourth step of drawing.
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CN113277727A (en) * | 2021-07-22 | 2021-08-20 | 武汉光谷航天三江激光产业技术研究院有限公司 | Preparation method of tapered-core optical fiber with gradually-changed core cladding ratio and tapered-core optical fiber |
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2002
- 2002-01-08 JP JP2002001812A patent/JP3977082B2/en not_active Expired - Lifetime
Cited By (2)
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CN113277727A (en) * | 2021-07-22 | 2021-08-20 | 武汉光谷航天三江激光产业技术研究院有限公司 | Preparation method of tapered-core optical fiber with gradually-changed core cladding ratio and tapered-core optical fiber |
CN113277727B (en) * | 2021-07-22 | 2021-11-09 | 武汉光谷航天三江激光产业技术研究院有限公司 | Preparation method of tapered-core optical fiber with gradually-changed core cladding ratio and tapered-core optical fiber |
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