JP6619838B2

JP6619838B2 - Optical fiber manufacturing method and optical fiber preform

Info

Publication number: JP6619838B2
Application number: JP2018085803A
Authority: JP
Inventors: 石田　格; 格石田
Original assignee: Fujikura Ltd
Current assignee: Fujikura Ltd
Priority date: 2018-04-26
Filing date: 2018-04-26
Publication date: 2019-12-11
Anticipated expiration: 2038-04-26
Also published as: JP2019189497A

Description

本発明は、光ファイバの製造方法、および光ファイバ母材に関する。 The present invention relates to an optical fiber manufacturing method and an optical fiber preform.

従来から、下記特許文献１に示されるように、複数の光ファイバ母材を用いて連続的に光ファイバ裸線を溶融紡糸する、光ファイバの製造方法が知られている。下記特許文献１では、第１光ファイバ母材の上端面と第２光ファイバ母材の下端面とを拡散接合法によって接合することで、これらの光ファイバ母材を一体化させている。 Conventionally, as shown in Patent Document 1 below, an optical fiber manufacturing method is known in which a plurality of optical fiber preforms are used to continuously melt and spin a bare optical fiber. In Patent Document 1 below, these optical fiber preforms are integrated by joining the upper end surface of the first optical fiber preform and the lower end surface of the second optical fiber preform by the diffusion bonding method.

特開平８−１０９０３６号公報JP-A-8-109036

上記特許文献１のように、光ファイバ母材同士を拡散接合法によって接合するには、接合部を予備加熱するための装置が必要となる。このため、製造装置全体の大型化や複雑化につながってしまう。 As in Patent Document 1, in order to join optical fiber preforms by diffusion bonding, an apparatus for preheating the joint is required. For this reason, it leads to the enlargement and complication of the whole manufacturing apparatus.

本発明はこのような事情を考慮してなされたもので、複数の光ファイバ母材を用いて連続的に溶融紡糸することが可能であり、かつ製造装置を簡略化することが可能な光ファイバの製造方法および光ファイバ母材を提供することを目的とする。 The present invention has been made in consideration of such circumstances, and an optical fiber that can be continuously melt-spun using a plurality of optical fiber preforms and that can simplify a manufacturing apparatus. An object of the present invention is to provide a manufacturing method and an optical fiber preform.

上記課題を解決するために、本発明の第１の態様に係る光ファイバの製造方法は、上端に第１連結部が設けられた第１母材を溶融紡糸する第１紡糸工程と、下端に第２連結部が設けられた第２母材を、前記第１母材の上方に配置する配置工程と、少なくとも前記第１連結部および前記第２連結部により構成される連結機構によって、前記第２母材を前記第１母材に連結する連結工程と、前記第２母材を溶融紡糸する第２紡糸工程と、を有する。 In order to solve the above-described problem, an optical fiber manufacturing method according to a first aspect of the present invention includes a first spinning step of melt spinning a first base material provided with a first connecting portion at an upper end, and a lower end at a lower end. The disposing step of disposing the second base material provided with the second connecting portion above the first base material, and the connecting mechanism constituted by at least the first connecting portion and the second connecting portion, A connecting step of connecting two base materials to the first base material, and a second spinning step of melt spinning the second base material.

また、上記課題を解決するために、本発明の第２の態様に係る光ファイバ母材は、溶融紡糸されることで光ファイバ裸線となる本体部と、前記本体部の上端面から上方に向けて延びる第１連結部と、前記本体部の下端面から下方に向けて延びる第２連結部と、を備える。 In order to solve the above-described problem, an optical fiber preform according to the second aspect of the present invention includes a main body that becomes a bare optical fiber by melt spinning, and an upper side from the upper end surface of the main body. A first connection portion extending toward the bottom, and a second connection portion extending downward from a lower end surface of the main body portion.

本発明の上記態様によれば、複数の光ファイバ母材を用いて連続的に溶融紡糸することが可能であり、かつ製造装置を簡略化することが可能な光ファイバの製造方法および光ファイバ母材を提供することができる。 According to the above aspect of the present invention, an optical fiber manufacturing method and an optical fiber preform that can be continuously melt-spun using a plurality of optical fiber preforms and that can simplify the manufacturing apparatus. Material can be provided.

第１実施形態に係る光ファイバの紡糸装置および光ファイバ母材の縦断面図である。1 is a longitudinal sectional view of an optical fiber spinning device and an optical fiber preform according to a first embodiment. 第１実施形態に係る連結機構の縦断面図である。It is a longitudinal cross-sectional view of the connection mechanism which concerns on 1st Embodiment. 第２実施形態に係る連結機構の縦断面図である。It is a longitudinal cross-sectional view of the connection mechanism which concerns on 2nd Embodiment. 図３の連結機構の斜視図である。It is a perspective view of the connection mechanism of FIG. 第２実施形態に係る第２光ファイバ母材の縦断面図である。It is a longitudinal section of the 2nd optical fiber preform concerning a 2nd embodiment. 第３実施形態に係る連結機構の縦断面図である。It is a longitudinal cross-sectional view of the connection mechanism which concerns on 3rd Embodiment. 第３実施形態に係る第２光ファイバ母材の縦断面図である。It is a longitudinal cross-sectional view of the 2nd optical fiber preform which concerns on 3rd Embodiment.

（第１実施形態）
以下、第１実施形態に係る光ファイバの製造方法および光ファイバ母材について、図面を参照しながら説明する。
本実施形態の光ファイバの製造方法は、例えば図１に示すような紡糸装置３０を用いて実施される。紡糸装置３０は、筐体３１と、ヒータ３２と、炉心管３３と、シール部３５と、を備えている。
炉心管３３内には第１光ファイバ母材（第１母材）１０が配置され、第１母材１０の上方には第２光ファイバ母材（第２母材）２０が配置されている。第１母材１０と第２母材２０とは、後述する連結機構Ｍ１を介して連結されている。紡糸装置３０は、母材１０、２０を加熱溶融させて細径化して引き出し、光ファイバ裸線を製造するための線引き炉である。 (First embodiment)
Hereinafter, an optical fiber manufacturing method and an optical fiber preform according to the first embodiment will be described with reference to the drawings.
The manufacturing method of the optical fiber of this embodiment is implemented using the spinning apparatus 30 as shown, for example in FIG. The spinning device 30 includes a casing 31, a heater 32, a core tube 33, and a seal portion 35.
A first optical fiber preform (first preform) 10 is disposed in the furnace core tube 33, and a second optical fiber preform (second preform) 20 is disposed above the first preform 10. . The 1st preform | base_material 10 and the 2nd preform | base_material 20 are connected via the connection mechanism M1 mentioned later. The spinning device 30 is a drawing furnace for producing a bare optical fiber by heating and melting the base materials 10 and 20 to reduce the diameter.

（方向定義）
本実施形態では、第１、第２母材１０、２０の中心軸Ｏに沿う方向を上下方向という。また、上下方向から見て、中心軸Ｏに交差する方向を径方向といい、中心軸Ｏを中心として周回する方向を周方向という。上下方向において第１母材１０が位置する側を下方といい、第２母材２０が位置する側を上方という。 (Direction definition)
In the present embodiment, the direction along the central axis O of the first and second base materials 10 and 20 is referred to as the vertical direction. Further, the direction intersecting the central axis O when viewed from the vertical direction is referred to as a radial direction, and the direction of circling around the central axis O is referred to as a circumferential direction. The side where the first base material 10 is located in the vertical direction is referred to as the lower side, and the side where the second base material 20 is located is referred to as the upper side.

母材１０、２０を、炉心管３３内でヒータ３２によって例えば約２０００℃に加熱し、溶融紡糸することで光ファイバ裸線が得られる。また、光ファイバ裸線の周囲に被覆層を設けることで、光ファイバ素線が得られる。なお、本明細書では、光ファイバ裸線および光ファイバ素線を総称して「光ファイバ」という。 The base materials 10 and 20 are heated to, for example, about 2000 ° C. by the heater 32 in the core tube 33 and melt-spun to obtain a bare optical fiber. In addition, an optical fiber can be obtained by providing a coating layer around the bare optical fiber. In this specification, the bare optical fiber and the optical fiber are collectively referred to as “optical fiber”.

炉心管３３は、上方に位置する上部３３ａと、下方に位置する下部３３ｂと、を有している。上部３３ａの内径は下部３３ｂの内径よりも大きく、上部３３ａの外径は下部３３ｂの外径よりも大きい。これにより炉心管３３は、２段の円筒状に形成されている。上部３３ａと下部３３ｂとは、隙間なく接続されていてもよいし、隙間が設けられていてもよい。上部３３ａの上端（炉心管３３の上端開口部）は、外部に向けて開口している。 The core tube 33 has an upper part 33a located above and a lower part 33b located below. The inner diameter of the upper part 33a is larger than the inner diameter of the lower part 33b, and the outer diameter of the upper part 33a is larger than the outer diameter of the lower part 33b. Thereby, the core tube 33 is formed in a two-stage cylindrical shape. The upper part 33a and the lower part 33b may be connected without a gap, or a gap may be provided. The upper end of the upper portion 33a (the upper end opening of the core tube 33) is open to the outside.

炉心管３３は、例えばカーボン材によって形成されている。炉心管３３は、母材１０、２０とともにヒータ３２によって加熱される。このため、炉心管３３の内部に酸素が存在すると、炉心管３３が加熱された際にカーボン材が酸化して消耗する。このため、炉心管３３の内部にはアルゴン（Ａｒ）やヘリウム（Ｈｅ）などの不活性ガスが充填されている。さらに、炉心管３３内に外気が進入しないように、炉心管３３の内部は陽圧に保たれている。 The core tube 33 is made of, for example, a carbon material. The core tube 33 is heated by the heater 32 together with the base materials 10 and 20. For this reason, if oxygen is present inside the core tube 33, the carbon material is oxidized and consumed when the core tube 33 is heated. For this reason, the inside of the furnace core tube 33 is filled with an inert gas such as argon (Ar) or helium (He). Further, the inside of the core tube 33 is kept at a positive pressure so that outside air does not enter the core tube 33.

また、炉心管３３内におけるガスの流れは、溶融紡糸して得られる光ファイバ裸線の外径に影響を与える。特に、炉心管３３内のガスの流れに乱れが生じると、光ファイバ裸線の外径が変動しやすくなる。したがって、炉心管３３内のガスの流れは、安定した層流状態であることが好ましい。そしてシール部３５は、炉心管３３内に外気が進入することを防ぎつつ、炉心管３３内のガスの流れを安定させるために設けられている。 Further, the gas flow in the core tube 33 affects the outer diameter of the bare optical fiber obtained by melt spinning. In particular, when the gas flow in the core tube 33 is disturbed, the outer diameter of the bare optical fiber is likely to fluctuate. Therefore, the gas flow in the core tube 33 is preferably in a stable laminar flow state. The seal portion 35 is provided to stabilize the flow of gas in the core tube 33 while preventing outside air from entering the core tube 33.

光ファイバ裸線は、紡糸装置３０の下方に配置された冷却装置（不図示）により冷却される。その後、冷却装置の下方に配置された被覆部（不図示）にて光ファイバ裸線の外周に被覆層が設けられて光ファイバ素線となる。さらに、光ファイバ素線は、引取装置（不図示）により所定の線速で引き取られた後、ボビン等に巻き取られる。 The bare optical fiber is cooled by a cooling device (not shown) disposed below the spinning device 30. Thereafter, a coating layer is provided on the outer periphery of the bare optical fiber at a coating portion (not shown) disposed below the cooling device to form an optical fiber. Further, the optical fiber is taken up at a predetermined linear speed by a take-up device (not shown) and then wound around a bobbin or the like.

第１母材１０、および第２母材２０は、例えば石英ガラスにより形成されている。母材１０、２０は、ＶＡＤ法やＯＶＤ法などによって得られた円柱状の本体部１１、２１に、後述の連結部を連結することにより得られる。
図１において、第１母材１０の下端部は、炉心管３３内に配置されており、光ファイバ裸線が溶融紡糸されている。第１母材１０と、第２母材２０とは、連結機構Ｍ１を介して連結されている。 The first base material 10 and the second base material 20 are made of, for example, quartz glass. The base materials 10 and 20 are obtained by connecting a connecting portion described later to columnar body portions 11 and 21 obtained by a VAD method, an OVD method, or the like.
In FIG. 1, the lower end part of the 1st preform | base_material 10 is arrange | positioned in the core tube 33, and the optical fiber bare wire is melt-spun. The first base material 10 and the second base material 20 are connected via a connection mechanism M1.

（第１母材）
図２に示すように、第１母材１０は、本体部１１および第１連結部１２を有している。本体部１１は円柱状に形成されている。第１連結部１２は、本体部１１の上方に設けられている。第１連結部１２は、円柱状に形成されており、本体部１１の上端面１１ａから上方に向けて延びている。第１連結部１２の外径は、本体部１１の外径よりも小さく、後述の第２連結部２２の内径よりも小さい。上下方向において、第１連結部１２の長さは、後述の第２連結部２２の長さと同等である。第１連結部１２には、第１連結部１２を径方向に貫く第１貫通孔１２ａが形成されている。第１貫通孔１２ａの内径は、後述の第２連結部２２の第２貫通孔２２ａと同等の大きさであり、後述のピンＰの外径よりも大きい。 (First base material)
As shown in FIG. 2, the first base material 10 has a main body portion 11 and a first connecting portion 12. The main body 11 is formed in a cylindrical shape. The first connecting part 12 is provided above the main body part 11. The first connecting portion 12 is formed in a columnar shape, and extends upward from the upper end surface 11 a of the main body portion 11. The outer diameter of the first connecting portion 12 is smaller than the outer diameter of the main body portion 11 and smaller than the inner diameter of the second connecting portion 22 described later. In the vertical direction, the length of the first connecting portion 12 is equivalent to the length of the second connecting portion 22 described later. The first connecting portion 12 is formed with a first through hole 12a that penetrates the first connecting portion 12 in the radial direction. The inner diameter of the first through hole 12a is the same size as the second through hole 22a of the second connecting portion 22 described later, and is larger than the outer diameter of the pin P described later.

（第２母材）
図１、２に示すように、第２母材２０は、本体部２１と、第１連結部２５と、第２連結部２２と、を有している。本体部２１は円柱状に形成されている。第１連結部２５は本体部２１の上方に設けられ、第２連結部２２は本体部２１の下方に設けられている。第２連結部２２は、本体部２１の下端面２１ａから下方に向けて延びる円筒状に形成されるとともに、第２連結部２２を径方向に貫く第２貫通孔２２ａを有する。第２連結部２２の外径は、第２母材２０の本体部２１の外径と同等の大きさである。これにより、本体部２１および第２連結部２２の外周面において、外径の変動に伴う上下方向の段差の発生を抑えることができる。第２連結部２２の内径は、第１連結部１２の外径よりも大きい。上下方向において、第２連結部２２の長さは、第１連結部１２の長さと同等である。これにより、円筒状の第２連結部２２の内部に第１連結部１２を挿入することが可能となる。 (Second base material)
As shown in FIGS. 1 and 2, the second base material 20 includes a main body portion 21, a first connecting portion 25, and a second connecting portion 22. The main body 21 is formed in a cylindrical shape. The first connecting part 25 is provided above the main body part 21, and the second connecting part 22 is provided below the main body part 21. The second connecting portion 22 is formed in a cylindrical shape extending downward from the lower end surface 21 a of the main body portion 21 and has a second through hole 22 a that penetrates the second connecting portion 22 in the radial direction. The outer diameter of the second connecting portion 22 is the same size as the outer diameter of the main body portion 21 of the second base material 20. Thereby, on the outer peripheral surface of the main-body part 21 and the 2nd connection part 22, generation | occurrence | production of the level | step difference of the up-down direction accompanying the fluctuation | variation of an outer diameter can be suppressed. The inner diameter of the second connecting portion 22 is larger than the outer diameter of the first connecting portion 12. In the vertical direction, the length of the second connecting portion 22 is equal to the length of the first connecting portion 12. As a result, the first connecting portion 12 can be inserted into the cylindrical second connecting portion 22.

図１に示すように、第１連結部２５は、円柱状に形成されており、第２母材２０の本体部２１の上端面２１ｂから上方に向けて延びている。また、第１連結部２５には、この第１連結部２５を径方向に貫く第１貫通孔２５ａが形成されている。第１貫通孔２５ａの内径は第２貫通孔２２ａの内径と同等である。第１連結部２５の外径は、第２連結部２２の内径よりも小さく、第１母材１０の第１連結部１２の外径と同等である。また、上下方向において、第１連結部２５の長さは、第２連結部２２および第１母材１０の第１連結部１２の長さと同等である。このように、第１連結部２５は、第１母材１０の第１連結部１２と同形状であり、かつ各部が同等の寸法となっている。このため、第２母材２０と同形状の他の母材を、第２母材２０の上端部に連結することができる。 As shown in FIG. 1, the first connecting portion 25 is formed in a columnar shape and extends upward from the upper end surface 21 b of the main body portion 21 of the second base material 20. The first connecting portion 25 is formed with a first through hole 25a that penetrates the first connecting portion 25 in the radial direction. The inner diameter of the first through hole 25a is equal to the inner diameter of the second through hole 22a. The outer diameter of the first connecting portion 25 is smaller than the inner diameter of the second connecting portion 22 and is equal to the outer diameter of the first connecting portion 12 of the first base material 10. Further, in the vertical direction, the length of the first connecting portion 25 is equal to the length of the second connecting portion 22 and the first connecting portion 12 of the first base material 10. Thus, the 1st connection part 25 is the same shape as the 1st connection part 12 of the 1st preform | base_material 10, and each part becomes an equivalent dimension. For this reason, another base material having the same shape as the second base material 20 can be connected to the upper end portion of the second base material 20.

なお、本実施形態では、第１連結部１２、２５は円柱状に形成されており、第２連結部２２は円筒状に形成されている。上記に限られず、第１連結部１２、２５は、母材１０、２０の本体部１１、２１の上端面１１ａ、２１ｂから上方に向けて延びるとともに、第１連結部１２、２５を径方向に貫く第１貫通孔１２ａ、２５ａを有していればよい。また、第２連結部２２は、第２母材２０の本体部２１の下端面２１ａから下方に向けて延びるとともに、第２連結部２２を径方向に貫く第２貫通孔２２ａを有していればよい。 In the present embodiment, the first connecting portions 12 and 25 are formed in a columnar shape, and the second connecting portion 22 is formed in a cylindrical shape. Not limited to the above, the first connecting portions 12 and 25 extend upward from the upper end surfaces 11a and 21b of the main body portions 11 and 21 of the base materials 10 and 20, and the first connecting portions 12 and 25 extend in the radial direction. What is necessary is just to have the 1st through-holes 12a and 25a which penetrate. The second connecting portion 22 has a second through hole 22a extending downward from the lower end surface 21a of the main body portion 21 of the second base material 20 and penetrating the second connecting portion 22 in the radial direction. That's fine.

例えば、第１連結部１２、２５は、１または複数の角柱状や板状に形成されており、第２連結部２２が前記角柱形状や板形状と組み合わさる１または複数の凹部を有していてもよい。または、各連結部１２、２２、２５は、母材１０、２０の外径と同等の外径を有する円柱を周方向で２分割した形状でもよい。 For example, the 1st connection parts 12 and 25 are formed in 1 or several prismatic shape or plate shape, and the 2nd coupling part 22 has 1 or several recessed part combined with the said prismatic shape or plate shape. May be. Or each connection part 12,22,25 may be the shape which divided | segmented the cylinder which has an outer diameter equivalent to the outer diameter of the base materials 10 and 20 into 2 in the circumferential direction.

各連結部１２、２２、２５は、それぞれの母材１０、２０の上下方向における端面に溶着により接続されている。 Each connection part 12, 22, 25 is connected to the end surface in the up-down direction of each base material 10, 20 by welding.

（連結機構）
ここで本実施形態では、第１貫通孔１２ａおよび第２貫通孔２２ａに、ピンＰが挿入されている。これにより、第１母材１０と第２母材２０とが連結されている。つまり、第１連結部１２、第２連結部２２、およびピンＰは、第１母材１０と第２母材２０とを連結する連結機構Ｍ１を構成している。
ピンＰは、円柱状のガラス棒であり、ピンＰの外径は、第１、第２貫通孔１２ａ、２２ａの内径よりも小さい。これによりピンＰは、第１、第２貫通孔１２ａ、２２ａ内に挿入可能となっている。ピンＰの円柱の長さは、母材１０、２０の本体部１１、２１の外径と同等である。ピンＰの両端部は、第２連結部２２の外周面の曲率と同等になるように形成されていてもよい。あるいは、ピンＰの長さが、第２連結部２２の外径よりも小さく、第２連結部２２の内径よりも大きくてもよい。これらの方法により、ピンＰが第１、第２貫通孔１２ａ、２２ａに挿入されたときに、ピンＰの端部が第２連結部２２の外周面から飛び出さないようにすることができる。 (Coupling mechanism)
Here, in this embodiment, the pin P is inserted in the 1st through-hole 12a and the 2nd through-hole 22a. Thereby, the 1st base material 10 and the 2nd base material 20 are connected. That is, the 1st connection part 12, the 2nd connection part 22, and the pin P comprise the connection mechanism M1 which connects the 1st preform | base_material 10 and the 2nd preform | base_material 20. FIG.
The pin P is a cylindrical glass rod, and the outer diameter of the pin P is smaller than the inner diameters of the first and second through holes 12a and 22a. Accordingly, the pin P can be inserted into the first and second through holes 12a and 22a. The length of the cylinder of the pin P is equal to the outer diameter of the main body portions 11 and 21 of the base materials 10 and 20. Both end portions of the pin P may be formed to be equal to the curvature of the outer peripheral surface of the second connecting portion 22. Alternatively, the length of the pin P may be smaller than the outer diameter of the second connecting portion 22 and larger than the inner diameter of the second connecting portion 22. By these methods, when the pin P is inserted into the first and second through holes 12a and 22a, the end portion of the pin P can be prevented from jumping out from the outer peripheral surface of the second connecting portion 22.

連結機構Ｍ１の外径は、第１、第２母材１０、２０の本体部１１、２１の外径と同等であることが好ましい。連結機構Ｍ１の外径が本体部１１，２１の外径より小さい場合、連結機構Ｍ１が炉心管３３の中に進入した時に、シール部３５と連結機構Ｍ１との隙間から炉心管３３内に外気が侵入し、炉心管３３内の温度が一時的に下がることがあるためである。本実施形態では、第２連結部２２の外径が本体部１１、２１の外径と同程度であるため、連結機構Ｍ１が炉心管３３内に進入した時の温度の変化を抑えることができる。また、外気の酸素により炉心管３３のカーボン材が酸化することを抑えることができる。 The outer diameter of the coupling mechanism M1 is preferably equal to the outer diameter of the main body portions 11 and 21 of the first and second base materials 10 and 20. When the outer diameter of the coupling mechanism M1 is smaller than the outer diameter of the main body parts 11 and 21, when the coupling mechanism M1 enters the core tube 33, the outside air enters the core tube 33 from the gap between the seal portion 35 and the coupling mechanism M1. This is because the temperature in the core tube 33 may temporarily drop. In the present embodiment, since the outer diameter of the second connecting portion 22 is approximately the same as the outer diameter of the main body portions 11 and 21, it is possible to suppress a change in temperature when the connecting mechanism M 1 enters the core tube 33. . Moreover, it can suppress that the carbon material of the core tube 33 is oxidized by oxygen of outside air.

（支持面）
第１連結部１２および第２連結部２２は、第１母材１０の荷重を受ける支持面Ｓ１を有している。本実施形態では、支持面Ｓ１は第１、第２貫通孔１２ａ、２２ａの内面であり、ピンＰを介して第１母材１０の荷重を受けている。支持面Ｓ１は、第２母材２０の本体部２１の下端面２１ａと、第１母材１０の本体部１１の上端面１１ａと、の間に位置している。つまり、支持面Ｓ１は第２母材２０の本体部２１の下端面２１ａよりも下方に位置している。各部材の寸法は、支持面Ｓ１およびピンＰが第１母材１０の荷重に耐えられるように決定される。 (Support surface)
The first connecting part 12 and the second connecting part 22 have a support surface S 1 that receives the load of the first base material 10. In the present embodiment, the support surface S1 is the inner surfaces of the first and second through holes 12a and 22a and receives the load of the first base material 10 via the pins P. The support surface S 1 is located between the lower end surface 21 a of the main body portion 21 of the second base material 20 and the upper end surface 11 a of the main body portion 11 of the first base material 10. That is, the support surface S 1 is positioned below the lower end surface 21 a of the main body portion 21 of the second base material 20. The dimension of each member is determined so that the support surface S 1 and the pin P can withstand the load of the first base material 10.

第１、第２連結部１２、２２、およびピンＰは、石英ガラスにより形成されている。すなわち、連結機構Ｍ１の各構成部材は、母材１０、２０の本体部１１、２１と同様に石英ガラスにより形成されている。このため、連結機構Ｍ１を炉心管３３内で溶融紡糸した場合、光ファイバ裸線を形成することができる。ただし、連結機構Ｍ１により形成される光ファイバ裸線は、良品部として用いなくてもよい。 The first and second connecting portions 12, 22 and the pin P are made of quartz glass. That is, each component member of the coupling mechanism M1 is made of quartz glass, similarly to the main body portions 11 and 21 of the base materials 10 and 20. For this reason, when the coupling mechanism M1 is melt-spun in the furnace core tube 33, a bare optical fiber can be formed. However, the bare optical fiber formed by the coupling mechanism M1 may not be used as a non-defective part.

第１連結部１２と第２連結部２２との間や、連結部１２、２２とピンＰとの間には、それぞれの寸法の違いにより隙間が存在する。詳細は後述するが、この隙間が原因となり発生する光ファイバ裸線内の泡の発生を抑えるため、径方向において、各隙間の断面積の和が連結機構Ｍ１の断面積に対して１０％以下となるように、各部の寸法を決定することが好ましい。 There is a gap between the first connecting portion 12 and the second connecting portion 22 or between the connecting portions 12 and 22 and the pin P due to the difference in dimensions. Although details will be described later, in order to suppress the generation of bubbles in the bare optical fiber caused by the gap, the sum of the sectional areas of the gaps in the radial direction is 10% or less with respect to the sectional area of the coupling mechanism M1. It is preferable to determine the dimensions of each part so that

（光ファイバの製造方法）
次に、２つの母材１０、２０を連結するための連結方法、および連結された２つの母材１０、２０から連続して光ファイバを製造する方法を説明する。 (Optical fiber manufacturing method)
Next, a connection method for connecting the two base materials 10 and 20 and a method for manufacturing an optical fiber continuously from the two connected base materials 10 and 20 will be described.

まず、第１把持部Ｈ１によって把持された第１母材１０の下端部を炉心管３３内に挿入し、第１母材１０を溶融紡糸する（第１紡糸工程）。なお、第１母材１０の上端面１１ａには予め第１連結部１２が設けられている。 First, the lower end portion of the first base material 10 gripped by the first gripping portion H1 is inserted into the core tube 33, and the first base material 10 is melt-spun (first spinning step). In addition, the 1st connection part 12 is provided in the upper end surface 11a of the 1st preform | base_material 10 previously.

次に、第２把持部Ｈ２によって把持された第２母材２０を、第１母材１０の上方に上下に移動可能なように配置する。そして第２母材２０を徐々に下降させ、第１連結部１２を第２連結部２２の内部に挿入する（配置工程）。この時に、周方向において第１貫通孔１２ａおよび第２貫通孔２２ａの位置を合わせて、同一の位置に配置されるように予め第２貫通孔２２ａの周方向における位置を第１貫通孔１２ａの位置と合わせてから、第２把持部Ｈ２により第２母材２０を把持する。若しくは、第２母材２０を周方向に回転させる回転機構（不図示）を用いて、第２貫通孔２２ａの周方向の位置を調整してもよい。 Next, the second base material 20 gripped by the second gripping portion H2 is disposed above the first base material 10 so as to be movable up and down. Then, the second base material 20 is gradually lowered, and the first connecting portion 12 is inserted into the second connecting portion 22 (arrangement step). At this time, the positions of the first through holes 12a and the second through holes 22a are aligned in the circumferential direction, and the positions of the second through holes 22a in the circumferential direction are set in advance so as to be arranged at the same position. After matching with the position, the second base material 20 is gripped by the second gripping portion H2. Or you may adjust the position of the circumferential direction of the 2nd through-hole 22a using the rotation mechanism (not shown) which rotates the 2nd preform | base_material 20 to the circumferential direction.

なお、第１母材１０の下端部では、紡糸が行われているため、第１母材１０は一定速度で降下し続けている。第１、第２貫通孔１２ａ、２２ａの周方向における位置を合わせた後は、第２母材２０も第１母材１０が下降する速度と同等の速度で降下させる。このため、第１母材１０および第２母材２０は、独立した把持装置により上下方向の位置を制御できることが好ましい。 In addition, since the spinning is performed at the lower end portion of the first base material 10, the first base material 10 continues to descend at a constant speed. After the positions of the first and second through holes 12a and 22a in the circumferential direction are matched, the second base material 20 is also lowered at a speed equivalent to the speed at which the first base material 10 is lowered. For this reason, it is preferable that the 1st preform | base_material 10 and the 2nd preform | base_material 20 can control the position of an up-down direction with an independent holding | gripping apparatus.

第２母材２０を下降させ、第１貫通孔１２ａおよび第２貫通孔２２ａの上下方向および周方向の位置が一致したところで、貫通孔１２ａ、２２ａにピンＰを挿通させ、２つの母材１０、２０を連結させる。すなわち、第１、第２連結部１２、２２およびピンＰにより構成される連結機構Ｍ１によって、第２母材２０を第１母材１０に連結する（連結工程）。この状態で、第１把持部Ｈ１による第１母材１０の把持を解放すると、支持面Ｓ１が第１母材１０の荷重を受ける。そして第１、第２母材１０、２０は、連結された状態で、第２把持部Ｈ２により把持されることになる。 The second base material 20 is lowered, and when the vertical and circumferential positions of the first through hole 12a and the second through hole 22a coincide with each other, the pin P is inserted into the through holes 12a and 22a, and the two base materials 10 are inserted. , 20 are connected. That is, the second base material 20 is connected to the first base material 10 by the connection mechanism M1 configured by the first and second connection portions 12 and 22 and the pin P (connection process). In this state, when the gripping of the first base material 10 by the first gripping part H 1 is released, the support surface S 1 receives the load of the first base material 10. The first and second base materials 10 and 20 are gripped by the second gripping portion H2 in a connected state.

ここで上述の通り、第１連結部１２と第２連結部２２との間や、連結部１２、２２とピンＰとの間には、それらの寸法の差による隙間が存在している。第１把持部Ｈ１による第１母材１０の把持が解放された時に、この隙間の分だけ第１母材１０が振動する可能性がある。この時の振動が大きい場合、紡糸中の光ファイバ裸線に振動が伝播し、光ファイバ裸線の断線が発生することもある。そのため、第１把持部Ｈ１の開放は低速で行うことが好ましい。若しくは、振動の発生を防止するための防振機構を設けてもよい。防振機構としては、例えば、上下方向において第１把持部Ｈ１とシール部３５との間に配置され、第１母材１０の本体部１１の外周面に接触する部材を用いてもよい。この場合、本体部１１の外周面に接触する部材により、上記の振動の発生を抑えることができる。 Here, as described above, there are gaps between the first connecting portion 12 and the second connecting portion 22 and between the connecting portions 12 and 22 and the pin P due to a difference in their dimensions. When the gripping of the first base material 10 by the first gripping portion H1 is released, the first base material 10 may vibrate by this gap. If the vibration at this time is large, the vibration may propagate to the bare optical fiber being spun and the bare optical fiber may be broken. Therefore, it is preferable to open the first gripping portion H1 at a low speed. Or you may provide the anti-vibration mechanism for preventing generation | occurrence | production of a vibration. As the vibration isolation mechanism, for example, a member that is disposed between the first gripping portion H1 and the seal portion 35 in the vertical direction and that contacts the outer peripheral surface of the main body portion 11 of the first base material 10 may be used. In this case, the occurrence of the vibration can be suppressed by the member that contacts the outer peripheral surface of the main body 11.

連結された母材１０、２０を一定速度で降下させ続けると、連結機構Ｍ１が炉心管３３の内部に進入する。連結機構Ｍ１は炉心管３３内で溶融して一体化され、光ファイバ裸線が紡糸される。
連結機構Ｍ１が紡糸された後にも、さらに第２母材２０は一定速度で降下し、溶融紡糸される。（第２紡糸工程）
第２紡糸工程中に、第２母材２０の上端部に、第２母材２０と同形状の他の母材を連結させることも可能である。このように、紡糸が行われている第２母材２０の上端部に他の母材を連結していくことで、連続的に光ファイバを紡糸することが可能になる。 When the connected base materials 10 and 20 are continuously lowered at a constant speed, the connection mechanism M1 enters the core tube 33. The coupling mechanism M1 is melted and integrated in the core tube 33, and the bare optical fiber is spun.
Even after the coupling mechanism M1 is spun, the second base material 20 is further lowered at a constant speed and melt-spun. (Second spinning process)
It is also possible to connect another base material having the same shape as the second base material 20 to the upper end portion of the second base material 20 during the second spinning process. In this manner, by connecting another base material to the upper end portion of the second base material 20 on which the spinning is performed, it becomes possible to continuously spin the optical fiber.

ここで、連結機構Ｍ１の各構成部材の間の隙間により発生する泡について、説明する。隙間に存在する空気により、連結機構Ｍ１から形成された光ファイバ裸線には泡が混入することがある。泡が混入した光ファイバ裸線は、泡の断面積分だけガラス部分の断面積が減少するため、強度が低下し、断線が発生しやすくなる。また、泡の混入した光ファイバ裸線を良品候補部から除外するため、連結機構Ｍ１により紡糸がされた開始点と終了点とを特定することが好ましい。このため、炉心管３３よりも下方に配置された泡検出装置（不図示）を用い、泡の混入した箇所を特定してもよい。このように、光ファイバ裸線内の泡を検出することで、光ファイバ裸線のうち、連結機構Ｍ１により形成された部分を検出する（泡検出工程）。 Here, bubbles generated by the gaps between the constituent members of the coupling mechanism M1 will be described. Bubbles may be mixed into the bare optical fiber formed from the coupling mechanism M1 due to the air present in the gap. In the bare optical fiber mixed with bubbles, the cross-sectional area of the glass portion is reduced by the cross-sectional area of the bubbles, so that the strength is lowered and disconnection is likely to occur. Further, in order to exclude the bare optical fiber mixed with bubbles from the good product candidate portion, it is preferable to specify the start point and the end point where the spinning is performed by the coupling mechanism M1. For this reason, you may identify the location where the bubble mixed using the bubble detection apparatus (not shown) arrange | positioned below the core tube 33. FIG. Thus, the part formed by the connection mechanism M1 is detected among the bare optical fibers by detecting the bubbles in the bare optical fibers (bubble detecting step).

泡検出装置としては、光ファイバの径方向から光を照射し、その散乱光から泡や混入物を検知する汎用の測定器を用いることができる。泡検出装置を用いることで、連結機構Ｍ１から形成された光ファイバを良品候補部から除外することができる。 As the bubble detection device, a general-purpose measuring device that irradiates light from the radial direction of the optical fiber and detects bubbles and contaminants from the scattered light can be used. By using the bubble detection device, the optical fiber formed from the coupling mechanism M1 can be excluded from the good product candidate portion.

また、連結機構Ｍ１から形成される光ファイバ裸線では、上述の通り断線が発生しやすい。断線の発生を抑えるために、連結機構Ｍ１を紡糸中は、光ファイバの製造線速を減速することが好ましい。また、光ファイバを引き取るための引取装置において、光ファイバの引取張力を下げてもよい。 Moreover, in the bare optical fiber formed from the coupling mechanism M1, disconnection is likely to occur as described above. In order to suppress the occurrence of disconnection, it is preferable to reduce the production line speed of the optical fiber while the coupling mechanism M1 is being spun. Further, in the take-up device for taking up the optical fiber, the take-up tension of the optical fiber may be lowered.

さらに、連結機構Ｍ１を紡糸中に、炉心管３３の下方に配置された補助引取装置（不図示）を用い、光ファイバ裸線の引取を補助してもよい。補助引取装置として、対向する２つの回転ベルトで光ファイバ裸線を挟み込むキャタピラ等を用いることができる。補助引取装置を用いた場合、仮に、紡糸装置３０よりも下方に配置されている冷却装置や被覆部で光ファイバが断線したとしても、補助引取装置よりも上方に残された光ファイバ裸線を引き出すことにより容易に光ファイバの製造を再開することができる。なお、補助引取装置は、良品候補部とならない連結機構Ｍ１を紡糸中にのみ用いることが好ましい。補助引取装置が光ファイバ裸線に接触することにより、光ファイバ裸線の外周に傷がつく恐れがあるためである。 Further, during spinning of the coupling mechanism M1, an auxiliary take-up device (not shown) disposed below the core tube 33 may be used to assist in taking up the bare optical fiber. As an auxiliary take-up device, a caterpillar or the like that sandwiches a bare optical fiber between two opposing rotating belts can be used. When the auxiliary take-up device is used, even if the optical fiber is disconnected at the cooling device or the covering portion arranged below the spinning device 30, the bare optical fiber left above the auxiliary take-up device is used. By pulling out, the production of the optical fiber can be easily resumed. In addition, it is preferable that an auxiliary take-up apparatus uses the connection mechanism M1 which does not become a good quality candidate part only during spinning. This is because when the auxiliary take-up device contacts the bare optical fiber, the outer periphery of the bare optical fiber may be damaged.

以上説明したように、本実施形態の光ファイバの製造方法によれば、上端に第１連結部１２が設けられた第１母材１０を溶融紡糸する第１紡糸工程と、下端に第２連結部２２が設けられた第２母材２０を、第１母材１０の上方に配置する配置工程と、第１連結部１２および第２連結部２２を含む連結機構Ｍ１によって、第２母材２０を第１母材１０に連結する連結工程と、第２母材２０を溶融紡糸する第２紡糸工程と、を有する。 As described above, according to the optical fiber manufacturing method of the present embodiment, the first spinning step of melt spinning the first base material 10 provided with the first coupling portion 12 at the upper end, and the second coupling at the lower end. The second base material 20 is provided by the disposing step of arranging the second base material 20 provided with the portion 22 above the first base material 10 and the connecting mechanism M1 including the first connecting portion 12 and the second connecting portion 22. The first base material 10 and the second base material 20 are melt-spun.

これにより、複数の光ファイバ母材１０、２０を用いて連続的に溶融紡糸することが可能となる。また、連結機構Ｍ１の予備加熱等をする必要がないため、製造装置の構成を簡略化することも可能となる。 This makes it possible to continuously melt and spin using a plurality of optical fiber preforms 10 and 20. Further, since it is not necessary to preheat the coupling mechanism M1, the configuration of the manufacturing apparatus can be simplified.

また、本実施形態の光ファイバ母材によれば、溶融紡糸されることで光ファイバ裸線となる本体部２１と、本体部２１の上端面２１ｂから上方に向けて延びる第１連結部２５と、本体部２１の下端面２１ａから下方に向けて延びる第２連結部２２と、を備える。
このように、本体部２１の上端面２１ｂおよび下端面２１ａにそれぞれ連結部２２、２５を備える光ファイバ母材２０を用いることにより、複数の光ファイバ母材２０を連結し、連続的に溶融紡糸することが可能となる。 Further, according to the optical fiber preform of the present embodiment, the main body portion 21 that becomes a bare optical fiber by melt spinning, and the first connecting portion 25 that extends upward from the upper end surface 21 b of the main body portion 21. And a second connecting portion 22 extending downward from the lower end surface 21a of the main body portion 21.
As described above, by using the optical fiber preform 20 including the coupling portions 22 and 25 on the upper end surface 21b and the lower end surface 21a of the main body portion 21, a plurality of optical fiber preforms 20 are coupled and continuously melt-spun. It becomes possible to do.

（第２実施形態）
次に、本発明に係る第２実施形態について説明するが、第１実施形態と基本的な構成は同様である。このため、同様の構成には同一の符号を付してその説明は省略し、異なる点についてのみ説明する。
本実施形態では、連結機構の構造が第１実施形態と異なる。 (Second Embodiment)
Next, a second embodiment according to the present invention will be described. The basic configuration is the same as that of the first embodiment. For this reason, the same code | symbol is attached | subjected to the same structure, the description is abbreviate | omitted, and only a different point is demonstrated.
In the present embodiment, the structure of the coupling mechanism is different from that of the first embodiment.

図３に示すように、本実施形態の連結機構Ｍ２は、第１連結部１３および第２連結部２３を備える。
第１連結部１３は、第１母材１０の本体部１１の上端面１１ａから上方に向けて延びる第１接続部１３ａと、第１接続部１３ａの上端部から径方向内側に向けて突出した第１凸部１３ｂと、を有する。
第２連結部２３は、第２母材２０の本体部２１の下端面２１ａから下方に向けて延びる第２接続部２３ａと、第２接続部２３ａの下端部から径方向内側に向けて突出した第２凸部２３ｂと、を有する。 As shown in FIG. 3, the connection mechanism M 2 of this embodiment includes a first connection part 13 and a second connection part 23.
The 1st connection part 13 protruded toward the radial inside from the 1st connection part 13a extended toward upper direction from the upper end surface 11a of the main-body part 11 of the 1st base material 10, and the upper end part of the 1st connection part 13a. 1st convex part 13b.
The 2nd connection part 23 protruded toward the radial inside from the 2nd connection part 23a extended toward the downward direction from the lower end surface 21a of the main-body part 21 of the 2nd base material 20, and the lower end part of the 2nd connection part 23a. 2nd convex part 23b.

図３、４に示すように、連結機構Ｍ２では、第１凸部１３ｂの下面である第１凸部下面１３ｂ１と、第２凸部の上面である第２凸部上面２３ｂ１とを重ねることで、第１、第２連結部１３、２３を連結させることができる。すなわち、第１凸部下面１３ｂ１および第２凸部上面２３ｂ１が、第１母材１０の荷重を受ける支持面Ｓ２となる。 As shown in FIGS. 3 and 4, in the coupling mechanism M2, the first convex portion lower surface 13b1 that is the lower surface of the first convex portion 13b and the second convex portion upper surface 23b1 that is the upper surface of the second convex portion are overlapped. The 1st, 2nd connection parts 13 and 23 can be connected. That is, the first convex portion lower surface 13 b 1 and the second convex portion upper surface 23 b 1 serve as a support surface S 2 that receives the load of the first base material 10.

本実施形態の連結工程では、第１実施形態とは異なり、第２凸部２３ｂの上下方向の位置を、第１凸部１３ｂと第１母材１０の本体部１１との間に合わせ、第２母材２０を径方向外側から第１母材１０に近づけることで２つの母材１０、２０を連結する。この場合、ピンＰ等の連結用の部材を用いることなく、母材同士を連結させることができる。このように、第２凸部２３ｂに第１凸部１３ｂを係止させることで、支持面Ｓ２が第１母材１０の荷重を受けることになる。また、支持面Ｓ２は、第２母材２０の本体部２１の下端面２１ａよりも下方に位置している。 In the connecting step of the present embodiment, unlike the first embodiment, the vertical position of the second convex portion 23b is aligned between the first convex portion 13b and the main body portion 11 of the first base material 10, and the second The two base materials 10 and 20 are connected by bringing the base material 20 close to the first base material 10 from the outside in the radial direction. In this case, the base materials can be connected without using a connecting member such as the pin P. Thus, the support surface S2 receives the load of the first base material 10 by locking the first convex portion 13b to the second convex portion 23b. Further, the support surface S 2 is located below the lower end surface 21 a of the main body portion 21 of the second base material 20.

図５に示すように、本実施形態の第２母材２０は、下端部には第２連結部２３が設けられており、上端部には第１連結部２６が設けられている。第１連結部２６は、第２母材２０の本体部２１の上端面２１ｂから上方に向けて延びる第１接続部２６ａと、第１接続部２６ａの上端部から径方向に向けて突出した第１凸部２６ｂを有する。第１連結部２６は、第１母材１０の第１連結部１３と同形状であり、かつ各部が同等の寸法となっている。このため、第２母材２０と同形状の他の母材を、第２母材２０の上端部に連結することができる。 As shown in FIG. 5, the 2nd base material 20 of this embodiment is provided with the 2nd connection part 23 in the lower end part, and the 1st connection part 26 is provided in the upper end part. The first connecting part 26 includes a first connecting part 26a extending upward from the upper end surface 21b of the main body part 21 of the second base material 20, and a first protruding part radially extending from the upper end part of the first connecting part 26a. It has 1 convex part 26b. The first connecting part 26 has the same shape as the first connecting part 13 of the first base material 10, and each part has the same dimensions. For this reason, another base material having the same shape as the second base material 20 can be connected to the upper end portion of the second base material 20.

（第３実施形態）
次に、本発明に係る第３実施形態について説明するが、第１実施形態と基本的な構成は同様である。このため、同様の構成には同一の符号を付してその説明は省略し、異なる点についてのみ説明する。
本実施形態では、連結機構の構造が第１実施形態と異なる。 (Third embodiment)
Next, a third embodiment according to the present invention will be described. The basic configuration is the same as that of the first embodiment. For this reason, the same code | symbol is attached | subjected to the same structure, the description is abbreviate | omitted, and only a different point is demonstrated.
In the present embodiment, the structure of the coupling mechanism is different from that of the first embodiment.

図６に示すように、本実施形態の連結機構Ｍ３は、第１連結部１４、第２連結部２４、および係止部材Ｅを備える。
第１連結部１４は、第１母材１０の本体部１１の上端面１１ａから上方に向けて延びる第１接続部１４ａと、第１接続部１４ａの上端部から径方向外側に向けて突出した第１凸部１４ｂと、を有する。第１接続部１４ａは円柱状に形成され、第１凸部１４ｂは環状に形成されている。
第２連結部２４は、第２母材２０の本体部２１の下端面２１ａから下方に向けて延びる第２接続部２４ａと、第２接続部２４ａの下端部から径方向外側に向けて突出した第２凸部２４ｂと、を有する。第２接続部２４ａは円柱状に形成され、第２凸部２４ｂは環状に形成されている。 As shown in FIG. 6, the connection mechanism M 3 of the present embodiment includes a first connection part 14, a second connection part 24, and a locking member E.
The 1st connection part 14 protruded toward the radial direction outer side from the 1st connection part 14a extended toward upper direction from the upper end surface 11a of the main-body part 11 of the 1st base material 10, and the upper end part of the 1st connection part 14a. 1st convex part 14b. The 1st connection part 14a is formed in the column shape, and the 1st convex part 14b is formed in cyclic | annular form.
The 2nd connection part 24 protruded toward the radial direction outer side from the 2nd connection part 24a extended toward the downward direction from the lower end surface 21a of the main-body part 21 of the 2nd preform | base_material 20, and the lower end part of the 2nd connection part 24a. 2nd convex part 24b. The 2nd connection part 24a is formed in the column shape, and the 2nd convex part 24b is formed in cyclic | annular form.

係止部材Ｅは、円筒を周方向で２分割した形状に形成されている。係止部材Ｅの上下方向における中央部の内面には、第１、第２凸部１４ｂ、２４ｂを係止させるための凹部が形成されている。係止部材Ｅは、第１、第２連結部１４、２４の径方向外側に配置される。係止部材Ｅは、第１、第２連結部１４、２４の径方向外側から取り付け可能となっている。
なお、係止部材Ｅは、円筒を周方向で３つ以上に分割した形状に形成されていてもよい。 The locking member E is formed in a shape obtained by dividing the cylinder into two in the circumferential direction. On the inner surface of the central portion in the vertical direction of the locking member E, a recess for locking the first and second convex portions 14b, 24b is formed. The locking member E is disposed on the radially outer side of the first and second connecting portions 14 and 24. The locking member E can be attached from the outside in the radial direction of the first and second connecting portions 14 and 24.
The locking member E may be formed in a shape obtained by dividing the cylinder into three or more in the circumferential direction.

本実施形態の連結工程では、第１母材１０に第２母材２０を上方から徐々に近づけて、第１、第２凸部１４ｂ、２４ｂを接触させた後に、係止部材Ｅを径方向外側から取り付ける。これにより、係止部材Ｅを第１凸部１４ｂおよび第２凸部２４ｂに係止する。この時、第１凸部１４ｂの下面である第１凸部下面１４ｂ１と、第２凸部２３ｂの上面である第２凸部上面２４ｂ１と、が支持面Ｓ３となる。すなわち、係止部材Ｅを介して、これらの支持面Ｓ３が第１母材１０の荷重を受けることになる。また、支持面Ｓ３は、第２母材２０の本体部２１の下端面２１ａよりも下方に位置している。 In the connecting step of the present embodiment, the second base material 20 is gradually brought closer to the first base material 10 from above and the first and second convex portions 14b and 24b are brought into contact with each other. Install from the outside. Thereby, the locking member E is locked to the first convex portion 14b and the second convex portion 24b. At this time, the first convex portion lower surface 14b1 that is the lower surface of the first convex portion 14b and the second convex portion upper surface 24b1 that is the upper surface of the second convex portion 23b serve as the support surface S3. That is, these support surfaces S3 receive the load of the first base material 10 via the locking member E. Further, the support surface S 3 is located below the lower end surface 21 a of the main body portion 21 of the second base material 20.

図７に示すように、本実施形態の第２母材２０は、下端部には第２連結部２４が設けられており、上端部には第１連結部２７が設けられている。第１連結部２７は、第２母材２０の本体部２１の上端面２１ｂから上方に向けて延びる第１接続部２７ａと、第１接続部２７ａの上端部から径方向外側に向けて突出した第１凸部２７ｂを有する。第１連結部２７は、第１母材１０の第１連結部１４と同形状であり、かつ各部が同等の寸法となっている。このため、第２母材２０と同形状の他の母材を、係止部材Ｅを介して第２母材２０の上端部に連結することができる。 As shown in FIG. 7, the 2nd base material 20 of this embodiment is provided with the 2nd connection part 24 in the lower end part, and the 1st connection part 27 is provided in the upper end part. The 1st connection part 27 protruded toward the radial direction outer side from the 1st connection part 27a extended toward upper direction from the upper end surface 21b of the main-body part 21 of the 2nd base material 20, and the 1st connection part 27a. It has the 1st convex part 27b. The 1st connection part 27 is the same shape as the 1st connection part 14 of the 1st preform | base_material 10, and each part becomes an equivalent dimension. For this reason, another base material having the same shape as the second base material 20 can be connected to the upper end portion of the second base material 20 via the locking member E.

なお、第１〜第３実施形態では、異なる形態の連結機構Ｍ１〜Ｍ３について説明した。各母材１０、２０を連結するために求められる強度に応じて、いずれの形態の連結機構Ｍ１〜Ｍ３を採用するかを適宜選択することができる。 In the first to third embodiments, different types of coupling mechanisms M1 to M3 have been described. Depending on the strength required for connecting the base materials 10 and 20, it is possible to appropriately select which form of the connection mechanism M1 to M3 is adopted.

以下、具体的な実施例を用いて、上記実施形態を説明する。なお、以下の実施例は本発明を限定するものではない。 The above embodiment will be described below using specific examples. The following examples do not limit the present invention.

光ファイバの製造装置を用い、図２に示す第１、第２母材１０、２０および連結機構Ｍ１を溶融紡糸し光ファイバの製造を行った。第１、第２母材１０、２０、および連結機構Ｍ１の各部材の寸法は以下の通りである。 Using an optical fiber manufacturing apparatus, the first and second preforms 10 and 20 and the coupling mechanism M1 shown in FIG. 2 were melt-spun to manufacture an optical fiber. The dimensions of the members of the first and second base materials 10 and 20 and the coupling mechanism M1 are as follows.

第１、第２母材１０、２０の本体部１１、２１の外径：５０ｍｍ
第１連結部１２の外径：２５ｍｍ
第２連結部２２の外径：５０ｍｍ
第２連結部２２の内径：２５．５ｍｍ
第１、第２連結部１２、２２の上下方向の長さ：１００ｍｍ Outer diameter of the main body parts 11 and 21 of the first and second base materials 10 and 20: 50 mm
The outer diameter of the first connecting part 12: 25 mm
The outer diameter of the second connecting portion 22: 50 mm
Inner diameter of second connecting portion 22: 25.5 mm
Length of the first and second connecting parts 12 and 22 in the vertical direction: 100 mm

また、第１、第２連結部１２、２２の上下方向における中心部に、以下の寸法の貫通孔１２ａ、２２ａを形成した。
第１、第２貫通孔１２ａ、２２ａの内径：１０ｍｍ
ピンＰの外径：９．８ｍｍ
ピンＰの円柱の長さ：４９ｍｍ Moreover, the through-holes 12a and 22a of the following dimensions were formed in the center part in the up-down direction of the 1st, 2nd connection parts 12 and 22. FIG.
Inner diameter of the first and second through holes 12a and 22a: 10 mm
Outer diameter of pin P: 9.8mm
Length of cylinder of pin P: 49mm

まず、第１把持部Ｈ１に把持された第１母材１０の下端部を炉心管３３の内部に配置し、線速１００ｍｍ／ｍｉｎで、光ファイバを製造した。第１把持部Ｈ１が炉心管３３のシール部３５に接触する前に、第２母材２０を第１母材１０の上方に配置し、第１連結部１２を第２連結部２２の内部に挿入後、ピンＰを第１、第２貫通孔１２ａ、２２ａに挿入した。その後、第１把持部Ｈ１の把持を徐々に開放した。解放直後には、第１母材１０に若干の振動が生じたが、光ファイバの断線は発生しなかった。 First, the lower end portion of the first base material 10 held by the first holding portion H1 was placed inside the core tube 33, and an optical fiber was manufactured at a linear speed of 100 mm / min. Before the first holding part H1 contacts the seal part 35 of the core tube 33, the second base material 20 is disposed above the first base material 10, and the first connecting part 12 is placed inside the second connecting part 22. After the insertion, the pin P was inserted into the first and second through holes 12a and 22a. Thereafter, the gripping of the first gripping part H1 was gradually released. Immediately after release, the first base material 10 was slightly vibrated, but no breakage of the optical fiber occurred.

さらに紡糸を続け、連結機構Ｍ１の紡糸が始まる前に線速を５０ｍｍ／ｍｉｎへ減速した。泡検出装置を用いて、泡の検出を行ったところ、連結機構Ｍ１を紡糸して得られた光ファイバ内には泡が検出されたが、断線は発生しなかった。連結機構Ｍ１を紡糸後、線速を再度１００ｍｍ／ｍｉｎまで増速し、第２母材２０の紡糸を行った。第２母材２０を紡糸した際には、断線等の異常を発生させることなく光ファイバを製造することができた。
このように、複数の光ファイバ母材を用いて連続的に溶融紡糸することが可能であることが判った。 Further, spinning was continued and the linear speed was reduced to 50 mm / min before spinning of the coupling mechanism M1 started. When bubbles were detected using the bubble detection device, bubbles were detected in the optical fiber obtained by spinning the coupling mechanism M1, but no disconnection occurred. After spinning the coupling mechanism M1, the linear velocity was increased again to 100 mm / min, and the second base material 20 was spun. When the second preform 20 was spun, an optical fiber could be manufactured without causing an abnormality such as disconnection.
Thus, it has been found that it is possible to continuously melt and spin using a plurality of optical fiber preforms.

なお、本発明の技術的範囲は前記実施の形態に限定されるものではなく、本発明の趣旨を逸脱しない範囲において種々の変更を加えることが可能である。 The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

例えば、第１実施形態において、１本のピンＰを用いて連結機構Ｍ１を構成したが、複数のピンＰを用いて連結機構Ｍ１を構成してもよい。この場合、例えば第１連結部１２および第２連結部２２における上下方向に異なる位置に、２箇所以上の貫通孔を配置してもよい。また、第１連結部１２および第２連結部２２にそれぞれ設けられた２つの貫通孔が、上下方向に異なる位置に配置され、径方向において直交する方向に延びていてもよい。この場合、支持面Ｓ１の面積が増大するため、２つの母材１０、２０を連結する強度が増す。さらに、第１母材１０の把持を解放した時の振動の抑制することができる。 For example, in the first embodiment, the coupling mechanism M1 is configured using one pin P, but the coupling mechanism M1 may be configured using a plurality of pins P. In this case, for example, two or more through holes may be arranged at different positions in the vertical direction in the first connecting portion 12 and the second connecting portion 22. Moreover, the two through holes provided in the first connecting part 12 and the second connecting part 22 may be arranged at different positions in the vertical direction and may extend in a direction perpendicular to the radial direction. In this case, since the area of support surface S1 increases, the intensity | strength which connects the two base materials 10 and 20 increases. Furthermore, vibration when the grip of the first base material 10 is released can be suppressed.

また、第１、第３実施形態では、ピンＰまたは係止部材Ｅを介して各連結部を連結したが、第２実施形態のように、連結機構Ｍ２は、少なくとも第１連結部および第２連結部により構成されていればよい。 In the first and third embodiments, the connecting portions are connected via the pin P or the locking member E. However, as in the second embodiment, the connecting mechanism M2 includes at least the first connecting portion and the second connecting portion. What is necessary is just to be comprised by the connection part.

その他、本発明の趣旨を逸脱しない範囲で、上記した実施の形態における構成要素を周知の構成要素に置き換えることは適宜可能であり、また、上記した実施形態や変形例を適宜組み合わせてもよい。 In addition, the constituent elements in the above-described embodiment can be appropriately replaced with known constituent elements without departing from the gist of the present invention, and the above-described embodiments and modifications may be appropriately combined.

１０…第１母材（光ファイバ母材）１１…（第１母材の）本体部１１ａ…上端面１２〜１４…第１連結部１２ａ…第１貫通孔１３ａ、１４ａ…第１接続部１３ｂ、１４ｂ…第１凸部１３ｂ１…第１凸部下面１４ｂ１…第１凸部下面２０…第２母材（光ファイバ母材）２１…（第２母材の）本体部２１ａ…下端面２２〜２４…第２連結部２５…第１連結部２２ａ…第２貫通孔２３ａ…第２接続部２３ｂ、２４ｂ…第２凸部２３ｂ１…第２凸部上面２４ｂ１…第２凸部上面Ｅ…係止部材Ｍ１〜Ｍ３…連結機構Ｏ…中心軸Ｐ…ピンＳ１〜Ｓ３…支持面 DESCRIPTION OF SYMBOLS 10 ... 1st preform | base_material (optical fiber preform | base_material) 11 ... Main part 11a (of 1st preform | base_material) 11a ... Upper end surface 12-14 ... 1st connection part 12a ... 1st through-hole 13a, 14a ... 1st connection part 13b , 14b ... 1st convex part 13b1 ... 1st convex part lower surface 14b1 ... 1st convex part lower surface 20 ... 2nd preform | base_material (optical fiber preform | base_material) 21 ... (2nd preform | base_material) main-body part 21a ... Lower end surface 22- 24 ... 2nd connection part 25 ... 1st connection part 22a ... 2nd through-hole 23a ... 2nd connection part 23b, 24b ... 2nd convex part 23b1 ... 2nd convex part upper surface 24b1 ... 2nd convex part upper surface E ... Locking Members M1 to M3 ... Connection mechanism O ... Center axis P ... Pins S1 to S3 ... Support surface

Claims

A first spinning step of melt spinning the first base material provided with the first connecting portion at the upper end;
An arrangement step of arranging a second base material provided with a second connecting portion at a lower end above the first base material;
A connecting step of connecting the second base material to the first base material by a connecting mechanism constituted by at least the first connecting portion and the second connecting portion;
A second spinning step of melt spinning the second base material.

The coupling mechanism has a support surface that receives a load of the first base material;
The method for manufacturing an optical fiber according to claim 1, wherein the support surface is positioned below a lower end surface of the main body portion of the second base material.

3. The optical fiber manufacturing method according to claim 1, further comprising: a bubble detection step of detecting a portion of the bare optical fiber formed by the coupling mechanism by detecting a bubble in the bare optical fiber. Method.

The first connecting portion extends upward from an upper end surface of the main body portion of the first base material, and has a first through hole penetrating the first connecting portion in a radial direction,
The second connection portion extends downward from a lower end surface of the main body portion of the second base material, and has a second through hole that penetrates the second connection portion in a radial direction.
In the arrangement step, the positions of the first through hole and the second through hole in the circumferential direction are aligned,
4. The optical fiber manufacturing method according to claim 1, wherein a pin is inserted through the first through hole and the second through hole in the connecting step. 5.

The first connecting portion includes a first connecting portion extending upward from an upper end surface of the main body of the first base material, and a first protrusion protruding radially inward from the upper end portion of the first connecting portion. And
The second connecting portion includes a second connection portion extending downward from a lower end surface of the main body portion of the second base material, and a second protrusion projecting radially inward from the lower end portion of the second connection portion. And
4. The optical fiber manufacturing method according to claim 1, wherein, in the connecting step, the first convex portion is locked to the second convex portion. 5.

The first connecting portion includes a first connection portion extending upward from an upper end surface of the main body portion of the first base material, and a first protrusion projecting radially outward from the upper end portion of the first connection portion. And
The second connecting portion includes a second connecting portion extending downward from a lower end surface of the main body portion of the second base material, and a second protrusion projecting radially outward from the lower end portion of the second connecting portion. And
The optical fiber manufacturing method according to any one of claims 1 to 3, wherein, in the connecting step, a locking member is locked to the first convex portion and the second convex portion.

A body portion that becomes a bare optical fiber by being melt-spun,
A first connecting portion extending upward from an upper end surface of the main body portion;
An optical fiber preform comprising: a second connecting portion extending downward from a lower end surface of the main body portion.

The optical fiber preform according to claim 7, wherein the first connection part and the second connection part are made of quartz glass.

The first connecting part has a first through hole penetrating the first connecting part in a radial direction,
The optical fiber preform according to claim 7 or 8, wherein the second connecting portion has a second through hole that penetrates the second connecting portion in a radial direction.

The first connecting portion includes a first connecting portion extending upward from an upper end surface of the main body portion, and a first convex portion protruding radially inward from the upper end portion of the first connecting portion. And
The second connecting portion includes a second connecting portion that extends downward from a lower end surface of the main body portion, and a second convex portion that protrudes radially inward from the lower end portion of the second connecting portion. The optical fiber preform according to claim 7 or 8.

The first connecting portion includes a first connecting portion extending upward from an upper end surface of the main body portion, and a first convex portion protruding radially outward from the upper end portion of the first connecting portion. And
The second connecting portion includes a second connecting portion that extends downward from a lower end surface of the main body portion, and a second convex portion that protrudes radially outward from the lower end portion of the second connecting portion. The optical fiber preform according to claim 7 or 8.