JPH01203238A - Production of optical fiber preform - Google Patents
Production of optical fiber preformInfo
- Publication number
- JPH01203238A JPH01203238A JP2576688A JP2576688A JPH01203238A JP H01203238 A JPH01203238 A JP H01203238A JP 2576688 A JP2576688 A JP 2576688A JP 2576688 A JP2576688 A JP 2576688A JP H01203238 A JPH01203238 A JP H01203238A
- Authority
- JP
- Japan
- Prior art keywords
- starting
- base material
- preform
- glass
- optical fiber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013307 optical fiber Substances 0.000 title claims abstract description 21
- 238000004519 manufacturing process Methods 0.000 title claims description 15
- 239000011521 glass Substances 0.000 claims abstract description 52
- 239000005373 porous glass Substances 0.000 claims abstract description 43
- 239000002245 particle Substances 0.000 claims abstract description 21
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 17
- 239000000112 cooling gas Substances 0.000 claims abstract description 9
- 238000000151 deposition Methods 0.000 claims abstract description 9
- 230000002194 synthesizing effect Effects 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims description 59
- 238000000034 method Methods 0.000 claims description 24
- 239000007789 gas Substances 0.000 claims description 18
- 239000010419 fine particle Substances 0.000 claims description 14
- 238000010438 heat treatment Methods 0.000 claims description 10
- 238000003786 synthesis reaction Methods 0.000 claims description 10
- 230000000694 effects Effects 0.000 claims description 9
- 239000000567 combustion gas Substances 0.000 claims description 7
- 239000002131 composite material Substances 0.000 claims description 4
- 238000002485 combustion reaction Methods 0.000 claims description 3
- 238000006460 hydrolysis reaction Methods 0.000 claims description 3
- 239000011159 matrix material Substances 0.000 claims 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 abstract description 11
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 9
- 239000010453 quartz Substances 0.000 abstract description 8
- 238000001816 cooling Methods 0.000 abstract description 6
- 238000009792 diffusion process Methods 0.000 abstract description 4
- 239000001307 helium Substances 0.000 abstract description 2
- 229910052734 helium Inorganic materials 0.000 abstract description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 abstract description 2
- 238000005253 cladding Methods 0.000 description 19
- 238000009826 distribution Methods 0.000 description 7
- 239000007858 starting material Substances 0.000 description 6
- 208000005156 Dehydration Diseases 0.000 description 5
- 230000018044 dehydration Effects 0.000 description 5
- 238000006297 dehydration reaction Methods 0.000 description 5
- 230000008021 deposition Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 239000011261 inert gas Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 210000004709 eyebrow Anatomy 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 238000001308 synthesis method Methods 0.000 description 2
- 101100243951 Caenorhabditis elegans pie-1 gene Proteins 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 241000219112 Cucumis Species 0.000 description 1
- 235000015510 Cucumis melo subsp melo Nutrition 0.000 description 1
- 238000004566 IR spectroscopy Methods 0.000 description 1
- FJJCIZWZNKZHII-UHFFFAOYSA-N [4,6-bis(cyanoamino)-1,3,5-triazin-2-yl]cyanamide Chemical compound N#CNC1=NC(NC#N)=NC(NC#N)=N1 FJJCIZWZNKZHII-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002366 halogen compounds Chemical class 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/012—Manufacture of preforms for drawing fibres or filaments
- C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
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】
［産業上の利用分野］
本発明は光ファイバ用母材の新規な製造方法に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel method for manufacturing an optical fiber preform.
光ファイバ用母材の製造方法としてＶＡＤ（気相軸付け
）法が知られている。ＶＡＤ法の概略を第２図を用いて
説明する。ＶＡＤ法ではガラス微粒子合成用バーナー２
．１にガラス原料ガス、燃焼用ガス、助燃ガス等を供給
して火炎加水分解反応によシ火炎２．２の中でガラス微
粒子２．５を発生させ、回転する出発材２．４の先端付
近にガラス微粒子を堆積させ多孔質ガラス母材２．５を
形成する。多孔質ガラス母材２．５の成長に合わせて出
発材ｚ４を軸方向にガラス微粒子合成用バーナ２．１と
相対的に移動させていくことによシ、多孔質ガラス母材
２．５を軸方向に成長させていく。２−６ｒｉ発生した
廃ガスの排出用の管である。A VAD (vapor phase attachment) method is known as a method for manufacturing optical fiber preforms. An outline of the VAD method will be explained using FIG. 2. In the VAD method, burner 2 for glass particle synthesis
．． A glass raw material gas, a combustion gas, an auxiliary combustion gas, etc. are supplied to 1 to cause a flame hydrolysis reaction, and glass particles 2.5 are generated in a flame 2.2 near the tip of the rotating starting material 2.4. Fine glass particles are deposited on the substrate to form a porous glass base material 2.5. By moving the starting material z4 in the axial direction relative to the glass fine particle synthesis burner 2.1 in accordance with the growth of the porous glass base material 2.5, the porous glass base material 2.5 is grown. It grows in the axial direction. This is a pipe for discharging waste gas generated by 2-6ri.
石英（ＳｔＯ，） 系光ファイバを作成する際には、
ガラス原料として８１Ｃｔ、 、 ８１ＨＣｔ、、
燃焼用ガスとしてＨ，、ＯＨ，、助燃ガスとして０鵞、
ガラス原料ガスのキャリアやバーナー保護のため不活性
ガスがガラス微粒子合成用バーナーに供給される場合が
多い。また所望の屈折率分布を形成する丸めに、８１０
．の屈折率を高めるＧｏｏ、の原料としてＧｅ０４をガ
ラス原料ガスに混入させることも一般的な手法である。When creating a quartz (StO,) based optical fiber,
81Ct, , 81HCt, , as glass raw materials
H, OH, as combustion gas, 0 as combustion aid gas,
Inert gas is often supplied to the burner for glass particle synthesis as a carrier for the frit gas and to protect the burner. In addition, 810
．． It is also a common method to mix Ge04 into the frit gas as a raw material for Goo, which increases the refractive index of the glass.
このようにして得られた多孔質ガラス母材は加熱脱水処
理、加熱透明化処理を経て透明な光ファイバ用母材とな
る。The porous glass preform thus obtained becomes a transparent preform for an optical fiber through a heating dehydration treatment and a heating transparentization treatment.
第２図に示したような一本のガラス微粒子合成用バーナ
ーで所望の屈折率分布を得ることができないときには、
第５図のように複数のガラス微粒子合成用バーナー五１
．五２を用いることがある。例えばバーナー五１に５ｉ
０４ 、 Ｇｅ０４を供給し、バーナー五２に５１ａｔ
、のみを供給することによシ、バーナー五１によ多形成
された多孔質ガラス母材の部位五３にのみＧｏｏ、を添
加する（バーナー五２により形成された多孔質ガラス母
材の部位五４にはＧｏｏ、が添加されない）。加熱透明
化後バーナー五１によ多形成されたＧｅ０１ を含む部
分のみ屈折率が高くなり、光を伝送するだめのコアーク
ラッド構造ができ上る。When the desired refractive index distribution cannot be obtained with a single glass particle synthesis burner as shown in Figure 2,
As shown in Fig. 5, a plurality of burners 51 for synthesizing glass particles
．． May 2 is sometimes used. For example, burner 51 to 5i
04, Ge04 is supplied and 51at is supplied to burner 52.
By supplying only , Goo is added only to the portion 53 of the porous glass preform formed by the burner 51 (the portion of the porous glass preform formed by the burner 52). Goo is not added to 54). After heating and transparency, only the portion containing Ge01 formed in the burner 51 has a high refractive index, and a core clad structure for transmitting light is completed.
しかしながら複数のバーナーを用いる場合には、２本の
バーナーの相対位置のガス流量、各々のバーナーによ多
形成された多孔質ガラス母材の成長速度を同一にするた
めの出発材移動速度等厳密に制御する必要のある製造条
件が多くなシ、多孔質ガラス体の製造を複雑にする。However, when using multiple burners, strict requirements such as the gas flow rate at the relative positions of the two burners and the starting material movement speed to make the growth rate of the porous glass base material formed by each burner the same are required. There are many manufacturing conditions that need to be controlled, which complicates the manufacturing of porous glass bodies.
一方、１本のバーナーでコアークラッドの２重構造を作
成することは難しいのでＧｏｏ、を含むコア部のみを形
成して加熱透明化処理段、これによシ得られた該コア用
母材をクラッドに相当する市販の石英パイプ中に挿入し
、一体化する方法がある。On the other hand, since it is difficult to create a double structure of core cladding with one burner, only the core part containing Goo is formed and then heated and transparentized. There is a method of inserting it into a commercially available quartz pipe equivalent to cladding and integrating it.
或いｄＧｅｌｏ、 を含む該コア用母材を所定径に延
伸したのち、第４図に示すように再度該コア用母材を出
発母材４．１として、ガラス微粒子合成用バーナー４２
によシガラス微粒子を該出発母材ζ１の外周部に堆積さ
せクラッドに相当する多孔質ガラス眉毛３を形成すると
ともに該多孔質ガラス層４３の成長に合わせて出発母材
４．１をバーナー歳２と相対的に移動させることにより
出発母材４１を取シ囲む多孔質ガラス体を形成し、しか
るのちに加熱脱水及び加熱透明化処理する方法がある。After stretching the core base material containing dGelo to a predetermined diameter, as shown in FIG.
Fine glass particles are deposited on the outer periphery of the starting base material ζ1 to form a porous glass eyebrow 3 corresponding to the cladding, and as the porous glass layer 43 grows, the starting base material 4.1 is heated using a burner 2. There is a method in which a porous glass body surrounding the starting base material 41 is formed by moving it relative to the starting base material 41, and then heat dehydration and heat transparency treatment are performed.
後者の方法では、コア用出発母材としてｑθ０゜を添加
し屈折率を高めたＳ１０．ガラスを用いればクラッドに
相当する部分は単に８１０．ガラスを形成すればよいし
、またコア材として純粋Ｓ１０．ガラスを用いれば、ク
ラッドに相当する部分には、多孔質ガラス層を１を含む
雰囲気で加熱することによシ？を添加しその屈折率を下
げることにより、やはシコア・クラッド構造が形成でき
る。In the latter method, the starting material for the core is S10. If glass is used, the portion corresponding to the cladding will simply be 810. It is sufficient to form glass, and pure S10. If glass is used, a porous glass layer is heated in an atmosphere containing 1 in the portion corresponding to the cladding. By adding and lowering the refractive index, a chicore clad structure can be formed.
〔発明が解決しようとする。ｉｌｌ！題〕ところで、光
ファイバの中でも中、長距離用通信に用いられるものは
低損失が要求されるが１、コア用母材を市販石英パイ１
に挿入一体化する方法では、石英パイプ中の不純物の影
響で損失が高くなシ易い。一方、クラッド部に相当する
多孔質ガラス層をコア用出発母材の周囲に形成する方法
では、クラッド用多孔質ガラス層形成時にガラス微粒子
合成用バーナーによ）発生するＨ、Ｏ成分がコア用、出
発母材中に拡散浸透し、光を吸収して損失を高くするＯ
Ｒ基をコア・クラッド界面近傍に多く（数百ｐｐｍ ）
含む光ファイバとなってしまう、という問題点がある。[The invention attempts to solve the problem. ill! By the way, among optical fibers, those used for medium to long-distance communication require low loss1, but the base material for the core is commercially available quartz pie1.
In the method of inserting and integrating into the quartz pipe, loss is likely to be high due to the influence of impurities in the quartz pipe. On the other hand, in the method of forming a porous glass layer corresponding to the cladding part around the starting base material for the core, H and O components generated by the burner for glass particle synthesis during the formation of the porous glass layer for the cladding are used for the core. , diffuses into the starting material and absorbs light, increasing the loss.
Many R groups near the core/cladding interface (several hundred ppm)
There is a problem in that the optical fiber ends up containing
特に単一モード光７アイパ′では、伝搬する光がコアの
みならずクラッド部にまで拡がっているので、コア・ク
ラッド界面近傍のＯＨ基の悪影響が強い。単一モードフ
ァイバではコア径に対して約４〜８倍のクラッド部まで
は十分にＯＨ基が低減されて約数十ｐｐｍ以下となって
いる必要がある。In particular, in the case of single mode light 7eyeper', the propagating light spreads not only to the core but also to the cladding, so the adverse effects of the OH groups near the core-cladding interface are strong. In a single mode fiber, the OH groups must be sufficiently reduced to about several tens of ppm or less up to the cladding portion, which is about 4 to 8 times the core diameter.
本発明は出発母材表面でのＯＨ基影形成びその内部への
ＯＨ基の拡散を抑止して多孔質ガラス層の形成を行うこ
とができ、これによシ低損失な光ファイバ用母材を製造
できる新規な方法を提供することを目的とするものであ
る。The present invention makes it possible to form a porous glass layer by suppressing the formation of OH group shadows on the surface of the starting base material and the diffusion of OH groups into the interior thereof, thereby making it possible to form a low-loss optical fiber base material. The purpose is to provide a new method for manufacturing.
ｃ課題を解決するための手段・作用〕
本発明は上記の課題を解決する手段として、ガラス微粒
子合成用バーナーにガラス原料ガス。(c) Means and Effects for Solving the Problems] The present invention provides a means for solving the above-mentioned problems by using a glass raw material gas in a burner for synthesizing glass particles.
燃焼用ガス、助燃ガスを供給して火炎加水分解反応させ
ることによりガラス微粒子を発生させ、該ガラス微粒子
を回転する出発母材外周部上に堆積させるとともに、該
出発母材を該ガラス微粒子合成用バーナーに対し相対的
にその軸方向に移動させることにより該出発母材を取シ
囲む多孔質ガラス層を形成し、しかるのちに該出発母材
と該多孔質ガラス層の複合体を加熱することによシ該多
孔質ガラス層を透明ガラス化して該出発母材とこれを取
勺囲む透明ガラス層の複合体からなる光ファイバ用母材
を製造する方法において、ガラス微粒子が堆積していな
い出発母材部を冷却しながら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用母材の製造方法を提供す
る。Glass fine particles are generated by supplying combustion gas and combustion assisting gas to cause a flame hydrolysis reaction, and the glass fine particles are deposited on the outer periphery of the rotating starting base material, and the starting base material is used for synthesizing the glass fine particles. forming a porous glass layer surrounding the starting base material by moving it in its axial direction relative to a burner, and then heating the composite of the starting base material and the porous glass layer; In a method for manufacturing an optical fiber base material comprising a composite of the starting base material and a transparent glass layer surrounding the starting base material by transparently vitrifying the porous glass layer, the starting material does not have glass fine particles deposited thereon. Provided is a method for manufacturing an optical fiber base material, which comprises depositing glass particles while cooling the base material.
本発明の特に好ましい実施態様としては、ガラス微粒子
が堆積していない出発母材部に冷却用ガスを吹きつける
上記方法および冷却用ガスに脱水作用のあるガスを混合
する上記方法が挙げられる。Particularly preferred embodiments of the present invention include the above-mentioned method in which a cooling gas is blown onto the starting base material on which glass fine particles are not deposited, and the above-mentioned method in which a gas having a dehydrating effect is mixed with the cooling gas.
まず本発明のように行なう根拠から説明すると、次のと
おシである。第４図に示した従来法では、クラッドに相
当する多孔質ガラス層４．３を、コア用出発母材４１の
外周に形成する際に、多孔質ガラス層４．３が形成され
る直前の出発母材部１の表面は、ガラス微粒子合成用バ
ーナー瓜２の熱によυ、約７００℃程度以上に加熱され
る。このよりな高温は、バーナー４．２の火炎から発生
するＨ、Ｏ成分や燃焼用ガスとして用いている■原子を
含む成分の出発母材表面からの内部への浸透を加速させ
る。First, the basis for carrying out the method according to the present invention will be explained as follows. In the conventional method shown in FIG. 4, when forming the porous glass layer 4.3 corresponding to the cladding on the outer periphery of the starting base material 41 for the core, immediately before the porous glass layer 4.3 is formed, The surface of the starting base material portion 1 is heated to about 700° C. or higher by the heat of the glass particle synthesis burner 2. This higher temperature accelerates the penetration of the H and O components generated from the flame of the burner 4.2 and the components containing the ■ atoms used as the combustion gas from the surface of the starting base material into the interior.
一方、出発母材部１の表面温度を下げるために、バーナ
ー４２に供給する燃焼ガスｉｔを低減したり、バーナー
表２を出発母材ｔ１から遠く離すなどの手段をとると、
多孔質ガラスノー４．５のガラス微粒子堆積面の温度が
下ってしまう。多孔質ガラス層表３はガラス微粒子の集
合体であるので、ガラス微粒子堆積面が５００〜４００
℃以上の高温に十分に加熱されていないと、ガラス微粒
子間のネック成長が進行せず、非常に壊れ易いものにな
ってしまう。On the other hand, if measures are taken to lower the surface temperature of the starting base material 1, such as reducing the amount of combustion gas it supplied to the burner 42 or moving the burner table 2 far away from the starting base material t1,
The temperature of the glass particle deposition surface of porous glass No. 4.5 drops. Since the porous glass layer Table 3 is an aggregate of glass fine particles, the glass fine particle deposition surface is 500 to 400.
If the glass is not heated sufficiently to a high temperature of 0.degree. C. or higher, the neck growth between the glass particles will not proceed and the glass will become extremely fragile.
本発明者らは以上の考察に鑑み、多孔質ガラス眉毛３の
ガラス微粒子堆積面を十分に高温にした状態で、かつ出
発母材４１表面を低温に保つことで問題点が解決し得る
と考え、種々検討の結果、出発母材を強制的に冷却する
ことが効果的であることを見出した。In view of the above considerations, the present inventors believe that the problem can be solved by keeping the glass particle deposition surface of the porous glass eyebrow 3 at a sufficiently high temperature and keeping the surface of the starting base material 41 at a low temperature. As a result of various studies, they found that it is effective to forcibly cool the starting base material.
以下、図面を参照して本発明を具体的に説明する。第１
図は本発明の一実ｍ列の説明図である。Hereinafter, the present invention will be specifically explained with reference to the drawings. 1st
The figure is an explanatory diagram of a single m-row of the present invention.
出発母材１．１表面の冷却にｒ１種々の方法が考えられ
るが、特に出発母材１．１の表面で多孔質ガラス層１．
３に覆われる直前の部分Ａが最もバーナーｔ２の形成す
る炎に近く高温になるので、この部分ムを局所的に冷却
することがよう効果的であ夛、そのためには、冷却用ガ
ス１．７をその部分にノズルｔ４等を用いて吹きつける
ことが好ましい。同図中、１．５はダミー石英棒、ｔ６
は排気管である。Various methods can be considered for cooling the surface of the starting base material 1.1, but in particular cooling the surface of the starting base material 1.1 with the porous glass layer 1.1.
Since the portion A immediately before being covered by the burner t2 is closest to the flame formed by the burner t2 and has a high temperature, it is effective to locally cool this portion. It is preferable to spray Nozzle 7 onto the area using a nozzle t4 or the like. In the same figure, 1.5 is a dummy quartz rod, t6
is the exhaust pipe.
該冷却用ガスとしてはガラス微粒子合成反応を乱すもの
や、また何らかの反応を起し逆に反応熱を発生するよう
なものは利用できないので、不活性ガスが好ましい。ま
た、不活性ガスの中でも熱伝導度の良いものはど冷却性
が良く代表的なものとしてヘリウムが挙げられる。As the cooling gas, it is preferable to use an inert gas, since it is impossible to use a gas that disturbs the glass particle synthesis reaction or a gas that causes some kind of reaction and generates heat of reaction. Furthermore, among inert gases, helium is a typical gas that has good thermal conductivity and good cooling properties.
さらに、本発明の冷却ガスに脱水作用のあるガスを混付
して吹きつけると、出発母材表面の吸着水分を除去でき
るのでより有効でおる。脱水作用のあるガスとしてはハ
ロゲン又はハロゲン化合物ガス列えばａｔ、、 ５ｏ
ｏｔ、 等が挙げられる。Furthermore, it is more effective to spray a mixture of the cooling gas of the present invention with a gas having a dehydrating effect, since the moisture adsorbed on the surface of the starting base material can be removed. Examples of gases that have a dehydrating effect include halogen or halogen compound gases such as at, 5o
ot, etc.
以上の説明では出発用母材としてコア用母材を用いた列
を挙げたが、本発明はこれに限定されるものではなく、
同様の構成で出発母材表面でのＯＨ基生成又は拡散を防
止する目的に適用できるものである。In the above explanation, the core base material is used as the starting base material, but the present invention is not limited to this.
A similar configuration can be applied to the purpose of preventing OH group formation or diffusion on the surface of the starting base material.
本発明における具体的な条件等は以下の実施列に示され
るが、本発明はこれらにより限定されるものではない。Although specific conditions and the like in the present invention are shown in the following examples, the present invention is not limited thereto.
実施列１
出発母材として、ＶＡＤ法で作製した約Ｓ７重１％のＧ
ｅ０ｇ を添加した石英ガラスからなるコア用母材を、
ＯＲ基が浸透しないように電気炉にて加熱して１０■φ
に延伸したものを準備した。該出発母材の屈折率分布を
第５図に示す。Practical row 1 As a starting base material, about S7 weight 1% G produced by VAD method
A core base material made of quartz glass doped with e0g,
Heat it in an electric furnace to prevent the OR group from penetrating to 10mm
A stretched version was prepared. The refractive index distribution of the starting base material is shown in FIG.
第１図に示すような構成で、本発明によシ、この出発母
材１．１の外周部に、ガラス微粒子合成用バーナーｔ２
を用いてクラッド部に相当する多孔質ガラス層ｔ３を形
成した。ガラス微粒子合成用バーナーｔ２には、Ｈ！
４５ Ｌ ７分、ＯＨ４０ｔ／分、８１０ｔ４ Ａ
０００ ＣＣ７分、ムｒガス１５ｔ／分を供給し、毎分
＆２ｔ／分の堆積速度でガラス微粒子（ａｉｏ、）
を堆積させていつｆｉｃ（堆積収率６５％）。出発母材
１．１はダミー石英棒１．５に接続され、５０ ｒｐｍ
で回転させつつ７５■／時の速度で移動させることによ
り、外径１３０■−の多孔質ガラス層を形成した。この
時冷却用ガスとしてＨｅ１Ｏ１／分を３−一の口径を有
するノズル１．４から出発母材ｔ１の表面に吹きつける
ことによυ、出発母材の多孔質ガラス層形成直前の部位
ムの表面温度を約ＳＯＯ℃にまで冷却した。しかるのち
、得られた母材を０１，６容ｆｉｔｓを含有するＨｅ
雰囲気中で１０５０℃に加熱し１時間保持したのち、Ｈ
・のみの雰囲気中で１６００℃に加熱し透明ガラス化し
た。得られた透明ガラス体の屈折率分布を第６図の（ａ
）部分に示す。なお同図においてＳ１はコア部、瓜２は
クラッドでおる。この時のコア径／クラツド径の比は１
：５であった。According to the present invention, with the configuration shown in FIG.
A porous glass layer t3 corresponding to the cladding portion was formed using the following method. The burner t2 for glass particle synthesis has H!
45 L 7 minutes, OH40t/min, 810t4A
000 CC for 7 minutes, supplying MR gas 15t/min, depositing glass particles (aio,) at a deposition rate of 2t/min/min.
fic (deposition yield 65%). The starting base material 1.1 is connected to a dummy quartz rod 1.5 and the speed of 50 rpm
A porous glass layer having an outer diameter of 130 cm was formed by rotating the glass at a speed of 75 cm/hour. At this time, by spraying He1O1/min as a cooling gas onto the surface of the starting base material t1 from a nozzle 1.4 having a diameter of 3-1, the area of the starting base material immediately before the formation of the porous glass layer is The surface temperature was cooled to about SOO°C. After that, the obtained base material was heated with He containing 0.1,6 volume fits.
After heating to 1050°C in an atmosphere and holding for 1 hour, H
・It was heated to 1600°C in an atmosphere of only 100 ml of chlorine to make it transparent vitrified. The refractive index distribution of the obtained transparent glass body is shown in Figure 6 (a
) section. In the same figure, S1 is the core part, and the melon 2 is the cladding. At this time, the ratio of core diameter/cladding diameter is 1
: It was 5.
該透明ガラス体を２０ｍの厚さにスライスし、赤外分光
々変針によシ断面内のＯｉｌ濃度分布を測定したところ
第６図の（ｂ） ｆｆｌｓ分に示すよりにコア・クラッ
ド界面近傍のＯＨ基濃度は約３０ｐｐｍと低いものであ
った。The transparent glass body was sliced to a thickness of 20 m, and the oil concentration distribution within the cross section was measured using an infrared spectroscopy needle. The OH group concentration was as low as about 30 ppm.
比較例１
実施列１において出発母材の冷却を行わず他は全く同様
の方法で透明ガラス母材を作製したところ、コア・クラ
ッド界面には約６００ ｐｐｍとい９高濃度のＯＲ基が
残留しておシ、実施例１の結果と比べると本発明の効果
が明らかに認められる。尚この時、クラッド用多孔質ガ
ラス体形成時の出発母材表面の温度は、８５０℃にまで
加熱されていた。Comparative Example 1 When a transparent glass base material was produced in the same manner as in Example 1 without cooling the starting base material, a high concentration of OR groups of approximately 600 ppm9 remained at the core-cladding interface. Furthermore, when compared with the results of Example 1, the effects of the present invention are clearly recognized. At this time, the temperature of the surface of the starting base material during formation of the porous glass body for cladding was heated to 850°C.
実施列２
実施例１において、冷却用ガスとしてＨｅ１０ｔ／分に
０４１０ｏｃｃ／分を混合して供給し、その他は同様に
して透明ガラス母材を作製したところ、コア・クラッド
界面のＯＨ基濃度は検出限界に近い〜１ ｐｐｍにまで
低減されてい友。この母材を１７−−に延伸したものを
出発母材どして、再度多孔質ガラス層を形成することに
よシ、クラツド径をコア径の１４倍にまで増加させた。Example 2 In Example 1, a mixture of He 10 t/min and 0410 occ/min was supplied as the cooling gas, and a transparent glass base material was produced in the same manner as in Example 1. The OH group concentration at the core-cladding interface was detected. It has been reduced to ~1 ppm, which is close to the limit. This base material was stretched 17 mm and used as a starting base material, and a porous glass layer was formed again, thereby increasing the cladding diameter to 14 times the core diameter.
この２度目の多孔質ガラス層の合成条件及びその加熱脱
水、加熱透明化条件は実施例１に記した第１の多孔質ガ
ラス層の合成条件及びその加熱脱水、加熱透明化条件と
同様である。このようにして得られ九光ファイバ用母材
を外径１２５・μｍ Ｋまで線引し九ところ波長ｔ５８
μｍでのＯＨ基による吸収損失は６ｄＥ／ｋａ＋Ｋｔで
低減されてい友。The conditions for synthesizing this second porous glass layer, its heating dehydration, and its heating transparency are the same as those of the first porous glass layer, its heating dehydration, and its heating transparency described in Example 1. . The nine optical fiber base materials obtained in this way were drawn to an outer diameter of 125 μm and a wavelength of t58 at nine points.
Absorption loss due to OH groups at μm is reduced by 6 dE/ka+Kt.
以上説明したように、本発明は出発母材外周部に多孔質
ガラス層を合成し、しかるのちに該多孔質ガラス層を加
熱脱水及び加熱透明化処理する光ファイバ用母材の製造
方法において、光ファイバの伝送損失特性上問題となる
。多孔質ガラス層合成時の出発母材表面でのＯＨ５の形
成及びその内部への拡散を抑止する効果がろ９、低損失
な光ファイバを得るための光ファイバ用母材の製造方法
として有効である。As explained above, the present invention provides a method for producing an optical fiber preform in which a porous glass layer is synthesized on the outer periphery of a starting preform, and then the porous glass layer is subjected to heat dehydration and heat transparency treatment. This poses a problem in terms of transmission loss characteristics of optical fibers. It has the effect of suppressing the formation of OH5 on the surface of the starting base material and its diffusion into the interior during synthesis of the porous glass layer, making it an effective method for producing an optical fiber base material to obtain a low-loss optical fiber. be.
第１図は本発明の多孔質ガラス層合成方法の実施態様の
説明図であシ、第２図および第６図は公知のＷＡＤ法に
よる多孔質ガラス母材作成方法の説明図、第４図ｒｓ、
従来の多孔質ガラスｊ−合成方法の説明図である。第５
図は本発明の実施１３’ｌＪ １および比較列１で用い
た出発母材の屈折率分布を示す図、第６図は本発明の実
施列１で作成したコア・クラッドを有する光ファイバ用
母材の屈折率分布を（ａ）部分に示し、これに対応する
母材半径方向のＯＨ基濃度分布を（ｂ）部分に示す図で
ある。FIG. 1 is an explanatory diagram of an embodiment of the porous glass layer synthesis method of the present invention, FIGS. 2 and 6 are explanatory diagrams of a method for producing a porous glass base material by the known WAD method, and FIG. rs,
It is an explanatory view of a conventional porous glass j-synthesis method. Fifth
The figure shows the refractive index distribution of the starting base materials used in Example 13'lJ 1 of the present invention and Comparative Row 1, and FIG. FIG. 3 is a diagram showing the refractive index distribution of the material in part (a) and the corresponding OH group concentration distribution in the radial direction of the base material in part (b).
Claims (3)
燃焼用ガス、助燃ガスを供給して火炎加水分解反応させ
ることによりガラス微粒子を発生させ、該ガラス微粒子
を回転する出発母材外周部上に堆積させるとともに、該
出発母材を該ガラス微粒子合成用バーナーに対し相対的
にその軸方向に移動させることにより該出発母材を取り
囲む多孔質ガラス層を形成し、しかるのちに該出発母材
と該多孔質ガラス層の複合体を加熱することにより該多
孔質ガラス層を透明ガラス化して該出発母材とこれを取
り囲む透明ガラス層の複合体からなる光ファイバ用母材
を製造する方法において、ガラス微粒子が堆積していな
い出発母材部を冷却しながら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用母材の製造方法。(1) Frit gas in the burner for glass particle synthesis;
Glass fine particles are generated by supplying combustion gas and combustion assisting gas to cause a flame hydrolysis reaction, and the glass fine particles are deposited on the outer periphery of the rotating starting base material, and the starting base material is used for synthesizing the glass fine particles. forming a porous glass layer surrounding the starting matrix by moving it in its axial direction relative to a burner, and then heating the composite of the starting matrix and the porous glass layer to In a method for producing an optical fiber preform consisting of a composite of a starting preform and a transparent glass layer surrounding it by converting a porous glass layer into transparent glass, a portion of the starting preform on which glass fine particles are not deposited is cooled. 1. A method for producing an optical fiber base material, the method comprising depositing glass fine particles while producing an optical fiber.
用ガスを吹きつけることを特徴とする特許請求の範囲第
１項に記載の光ファイバ用母材の製造方法。(2) The method for manufacturing an optical fiber preform according to claim 1, characterized in that a cooling gas is blown onto the starting preform on which glass fine particles are not deposited.
を特徴とする特許請求の範囲第２項に記載の光ファイバ
用母材の製造方法。(3) The method for manufacturing an optical fiber preform according to claim 2, characterized in that a gas having a dehydrating effect is mixed with the cooling gas.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2576688A JPH01203238A (en) | 1988-02-08 | 1988-02-08 | Production of optical fiber preform |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2576688A JPH01203238A (en) | 1988-02-08 | 1988-02-08 | Production of optical fiber preform |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01203238A true JPH01203238A (en) | 1989-08-16 |
Family
ID=12174962
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2576688A Pending JPH01203238A (en) | 1988-02-08 | 1988-02-08 | Production of optical fiber preform |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01203238A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8297079B2 (en) | 2004-01-07 | 2012-10-30 | Shin-Etsu Chemical Co., Ltd. | Method of manufacturing porous glass base material used for optical fibers, and glass base material |
| US8567217B2 (en) | 2003-05-09 | 2013-10-29 | Fujikura Ltd. | Optical fiber preform and manufacturing method therefor |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62108748A (en) * | 1985-11-08 | 1987-05-20 | Fujikura Ltd | Preparation of glass fiber base material |
| JPH01111747A (en) * | 1987-10-23 | 1989-04-28 | Hitachi Cable Ltd | Production of optical fiber preform |
-
1988
- 1988-02-08 JP JP2576688A patent/JPH01203238A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62108748A (en) * | 1985-11-08 | 1987-05-20 | Fujikura Ltd | Preparation of glass fiber base material |
| JPH01111747A (en) * | 1987-10-23 | 1989-04-28 | Hitachi Cable Ltd | Production of optical fiber preform |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8567217B2 (en) | 2003-05-09 | 2013-10-29 | Fujikura Ltd. | Optical fiber preform and manufacturing method therefor |
| US8297079B2 (en) | 2004-01-07 | 2012-10-30 | Shin-Etsu Chemical Co., Ltd. | Method of manufacturing porous glass base material used for optical fibers, and glass base material |
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