JP2988524B2 - Optical fiber and method for manufacturing the same - Google Patents

Optical fiber and method for manufacturing the same

Info

Publication number
JP2988524B2
JP2988524B2 JP63232632A JP23263288A JP2988524B2 JP 2988524 B2 JP2988524 B2 JP 2988524B2 JP 63232632 A JP63232632 A JP 63232632A JP 23263288 A JP23263288 A JP 23263288A JP 2988524 B2 JP2988524 B2 JP 2988524B2
Authority
JP
Japan
Prior art keywords
core
clad
glass
cladding
quartz glass
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
JP63232632A
Other languages
Japanese (ja)
Other versions
JPH0281004A (en
Inventor
良三 山内
朗 和田
吉哉 磯野
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujikura Ltd
Original Assignee
Fujikura Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Fujikura Ltd filed Critical Fujikura Ltd
Priority to JP63232632A priority Critical patent/JP2988524B2/en
Publication of JPH0281004A publication Critical patent/JPH0281004A/en
Application granted granted Critical
Publication of JP2988524B2 publication Critical patent/JP2988524B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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
    • 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]
    • C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/02—Pure silica glass, e.g. pure fused quartz
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2203/00—Fibre product details, e.g. structure, shape
    • C03B2203/10—Internal structure or shape details
    • C03B2203/22—Radial profile of refractive index, composition or softening point

Description

【発明の詳細な説明】 （産業上に利用分野） この発明は、光ファイバおよびその製造方法に関する
もので、特に低損失な光ファイバに関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber and a method for manufacturing the same, and more particularly to a low-loss optical fiber.

（従来の技術） 光ファイバの一般的製法として、VADや外付け法によ
ってコア−クラッド型の母材を製造し、これを線引きし
てファイバ化するという方法がある。(Prior Art) As a general manufacturing method of an optical fiber, there is a method of manufacturing a core-clad type base material by VAD or an external method, and drawing this into a fiber.

（発明が解決しようとする課題） しかしながら近年光ファイバの低損失化が進むにつれ
て非常に微少な損失原因まで問題とされるようになって
きている。そのうちの一つにファイバ中の線引きに依存
した残留応力の問題がある。(Problems to be Solved by the Invention) However, in recent years, as the loss of the optical fiber has been reduced, a very small cause of the loss has become a problem. One of them is a problem of residual stress depending on drawing in a fiber.

例えば、ファイバ中に軟化温度の異なる部分があると
その高い部分は線引き炉から引き出されてまず真っ先に
固化する。しかし軟化温度の低い部分はまだ粘度が低い
状態にある。その結果、軟化温度が高い部分のみに線引
き時の引張り応力が印加されることになり弾性歪を受け
ることになる。他の部分もファイバがしばらく走行する
うちに固化するが、先に弾性歪を受けていた軟化温度が
高い部分は後から固化した部分の粘性に妨げられて直ち
に応力緩和することができず、その応力のかなりの部分
が残留することになる。もう一つの残留応力は熱膨脹係
数のミスマッチにより起こる。すなわち仮にファイバの
全ての部分の軟化温度が等しいとしても、もし特定の部
分の熱膨脹係数が他の部分と比べて大きいとすると、線
引き炉からでて1400℃程度の温度から常温にまで至る間
にこの部分は大きく収縮しようとする。具体的にはこの
部分は通常のファイバではゲルマニウムをドーパントと
して多量に含むコア部であることが多い。その結果この
熱膨脹係数が大きいコア部分は線引き後に引張り歪を残
留することになり、その結果ガラスの屈折率ゆらぎが増
大しファイバのロス増を生じさせることになる。For example, if there is a portion of the fiber having a different softening temperature, the higher portion is drawn out of the drawing furnace and solidifies first. However, the portion having a low softening temperature is still in a low viscosity state. As a result, a tensile stress at the time of drawing is applied only to a portion having a high softening temperature, so that elastic strain occurs. The other part also solidifies while the fiber travels for a while, but the part with a high softening temperature that was previously subjected to elastic strain cannot be immediately relaxed due to the viscosity of the solidified part afterwards, A significant portion of the stress will remain. Another residual stress is caused by thermal expansion coefficient mismatch. That is, even if the softening temperatures of all parts of the fiber are equal, if the specific part has a larger coefficient of thermal expansion than the other parts, it will take about 1400 ° C to reach room temperature from the drawing furnace. This part tends to shrink significantly. Specifically, this portion is often a core portion containing a large amount of germanium as a dopant in an ordinary fiber. As a result, the core portion having a large coefficient of thermal expansion retains tensile strain after drawing, and as a result, the fluctuation of the refractive index of the glass increases and the loss of the fiber increases.

以上の考察の結果、光ファイバが損失増加をおこすの
はコアガラスに非常に近いクラッド部のガラスかコアガ
ラスに引張り歪が残留した場合であり、これらを生じさ
せないためには理想的にはクラッドガラスを非常に均一
に作製してクラッドのどこか特定の局所領域に不要な線
引き時の引張り歪が残留しないようにするとともに、均
一なクラッド全体に発生した引張り歪が線引き後は消失
することを利用して、ドーパント添加に伴うコアの熱歪
を同時にキャンセルすることが考えられる。As a result of the above considerations, the optical fiber causes an increase in loss when tensile strain remains in the glass in the clad part very close to the core glass or the core glass. The glass is made very uniform so that the tensile strain during unnecessary drawing does not remain in a specific local area somewhere in the cladding, and that the tensile strain generated in the entire uniform cladding disappears after drawing. It is conceivable that the thermal distortion of the core accompanying the addition of the dopant is simultaneously canceled by using the dopant.

しかしながら、非常に大きな断面積のクラッド部を完
全に一様にするのは製作上コスト的に必ずしも有利では
ない。However, it is not always advantageous in terms of manufacturing cost to make the clad portion having a very large cross-sectional area completely uniform.

（課題を解決するための手段） そこでこの発明では、 （１） コアガラスをドーパントを含み、軟化温度が相
対的に低いものにする。(Means for Solving the Problems) Therefore, in the present invention, (1) The core glass contains a dopant and has a relatively low softening temperature.

（２） コアガラスの周囲に少量で、かつガラスの屈折
率をほとんど変化させない程度のガラス組成の変化によ
り、その外側のクラッドよりも軟化温度が低いガラスを
コア直近のクラッドガラスとして配置する。(2) A small amount of glass having a softening temperature lower than that of the outer clad is disposed as a clad glass near the core due to a small change in the glass composition that does not substantially change the refractive index of the glass around the core glass.

（３） 上記（２）のガラスよりも高い軟化温度を有す
るガラスを第２のクラッドガラスとする。(3) A glass having a higher softening temperature than the glass of the above (2) is used as a second clad glass.

このとき、第２のクラッドガラスの断面積を上記
（１）、（２）のそれよりも大きくする。At this time, the cross-sectional area of the second clad glass is made larger than those of the above (1) and (2).

すなわちこの発明は、ガラスの軟化温度が中心から外
側に向かって順次高くしてなる石英ガラス系母材を用意
し、これを線引きしてファイバ化するようにしたもので
ある。石英ガラスの軟化温度を調整する手段としては、
ゲルマニウム、リン、ほう素等の金属酸化物、フッ素、
塩素系の陰イオン、酸素等があげられるが、導波炉を構
成する屈折率の調整という観点からコアにはゲルマニウ
ムを主とする金属酸化物が、クラッドには陰イオン、酸
素が添加される。その場合クラッドの厚さが十分に厚い
ので複数層にして添加される陰イオン、酸素の量を内側
から外側にむかって順次減少するようにしてそれらの軟
化温度が内側から外側にむかって順次高くなるようにす
る。ただし屈曲率についてはほとんど変わらない程度、
すなわち±0.02％程度とされる。That is, in the present invention, a quartz glass base material is prepared in which the softening temperature of the glass is gradually increased from the center toward the outside, and this is drawn into a fiber. As means for adjusting the softening temperature of quartz glass,
Metal oxides such as germanium, phosphorus and boron, fluorine,
Chlorine-based anions, oxygen, etc. are mentioned. From the viewpoint of adjusting the refractive index constituting the waveguide furnace, a metal oxide mainly containing germanium is added to the core, and anions and oxygen are added to the cladding. . In that case, the thickness of the clad is sufficiently thick so that the amount of anions and oxygen added in multiple layers is gradually reduced from the inside to the outside so that their softening temperatures are gradually increased from the inside to the outside. To be. However, the degree of bending is almost unchanged,
That is, it is about ± 0.02%.

（実施例） VAD法により、ゲルマニアを5wt％含む直径5mm,長さ30
0mmのコア用SiO2ガラスロッドを用意し、この周りに第
１図に示す外付け法により32mm厚にSiO2多孔質ガラス微
粒子を堆積させた。図において、１はGeO2がドープされ
たコア用SiO2ガラスロッドでその軸の周りに40rpmで回
転される。２はコア用ロッド１の軸方向に200mm/分の速
度でトラバースされる４重管バーナで、中心から外側に
向けて順次SiCl40.3／分、Ar0.5／分、H26／分、
O210／分が供給されて火炎３によりSiO2ガラス微粒子
を生成させる。４はロッド１の周りに堆積されたSiO2ガ
ラス微粒子層である。次にこのSiO2多孔質ガラス粒子が
堆積されたロッドを第２図に示す最高温度が1620℃、Cl
2の温度が0.5％、ヘリウム99.5％の雰囲気炉内に10mm/
分の速度で導入して透明ガラス化させて、Cl2を0.3％含
む厚さ10mmの第１のクラッドガラスを有する外径25mmの
ロッドを得た。第２図において５は石英マッフルチュー
ブ、６はこの石英マッフルチューブ５の底部に設けられ
た雰囲気ガス供給口である。７はガス排出口、８はヒー
タである。次にこの第１のクラッド層が形成されたロッ
ド上に第１図に示した外付け法により再度80mm厚にSiO2
多孔質ガラス微粒子を堆積させた。このときの条件は第
１のクラッドガラスを得るときと同一とした。(Example) 5 mm in diameter and 30 in length containing 5 wt% of germania by VAD method
A 0 mm SiO 2 glass rod for a core was prepared, and around this, SiO 2 porous glass fine particles were deposited to a thickness of 32 mm by an external method shown in FIG. In the figure, 1 is a core SiO 2 glass rod doped with GeO 2 and rotated around its axis at 40 rpm. Reference numeral 2 denotes a quadruple tube burner traversed at a speed of 200 mm / min in the axial direction of the core rod 1. From the center outward, SiCl 4 0.3 / min, Ar 0.5 / min, H 2 6 / min,
O 2 10 / min is supplied, and the flame 3 generates SiO 2 glass fine particles. Reference numeral 4 denotes a SiO 2 glass fine particle layer deposited around the rod 1. Next, the rod on which the SiO 2 porous glass particles were deposited was heated at a maximum temperature of 1620 ° C.
Temperature of 2 0.5%, 10 mm to 99.5% atmosphere furnace in the helium /
The mixture was introduced at a speed of 1 minute to be vitrified to obtain a rod having an outer diameter of 25 mm and a first clad glass having a thickness of 10 mm and containing 0.3% of Cl 2 . In FIG. 2, reference numeral 5 denotes a quartz muffle tube, and reference numeral 6 denotes an atmosphere gas supply port provided at the bottom of the quartz muffle tube 5. 7 is a gas outlet, and 8 is a heater. Next, on the rod on which the first cladding layer was formed, SiO 2 was again formed to a thickness of 80 mm by the external method shown in FIG.
Porous glass particles were deposited. The conditions at this time were the same as when the first clad glass was obtained.

次にSiO2多孔質ガラス微粒子が堆積されたロッドを第
２図に示す炉を用いて透明ガラス化させてO2を１％含む
厚さ17.5mmの第２のクラッドガラスを有する外径60mmの
ロッドとした。このときの条件は第１のクラッドガラス
を得るときと比較して炉内の雰囲気ガスの種類をヘリウ
ム99％、O21％に変えた以外は同じとした。得られたこ
のロッドを2050℃で線引きし、コア径10.5μｍ、第１の
クラッド径65μｍ、第２のクラッド径125μｍのファイ
バを得た。Next, the rod on which the SiO 2 porous glass fine particles are deposited is transparently vitrified by using the furnace shown in FIG. 2 and has a 17.5 mm-thick second clad glass containing 1% of O 2 and having an outer diameter of 60 mm. A rod was used. The conditions at this time were the same as those for obtaining the first clad glass, except that the type of atmosphere gas in the furnace was changed to helium 99% and O 2 1%. The obtained rod was drawn at 2050 ° C. to obtain a fiber having a core diameter of 10.5 μm, a first cladding diameter of 65 μm, and a second cladding diameter of 125 μm.

なお、補強のためにこのファイバ化の直後に紫外線硬
化型の樹脂を62μｍ厚に施した。第３図は得られたファ
イバの温度1200℃における粘度の推定値を示したもの
で、コアが約107ボアズ、第１のクラッドが約５×1010
ボアズ、第２のクラッドが約1011ボアズであり中心から
外側に向かって順次粘度が高くなっている。またその屈
折率は、コアは1.463、第１のクラッドは1.459、第２の
クラッドは1.458となっている。さらに第４図はファイ
バの損失波長特性を調べたものである。同図中（イ）は
この発明のファイバ、（ロ）はクラッドガラスの軟化温
度調整を行っていない従来法によるファイバの損失波長
特性を示している。Immediately after the formation of the fiber, an ultraviolet curable resin was applied to a thickness of 62 μm for reinforcement. FIG. 3 shows the estimated value of the viscosity of the obtained fiber at a temperature of 1200 ° C., in which the core is about 10 7 boas and the first clad is about 5 × 10 10
The bores and the second cladding are about 10 11 bores, and the viscosity increases gradually from the center toward the outside. The refractive index of the core is 1.463, that of the first cladding is 1.449, and that of the second cladding is 1.458. FIG. 4 shows the result of examining the loss wavelength characteristics of the fiber. In the figure, (a) shows the loss wavelength characteristics of the fiber according to the present invention, and (b) shows the loss wavelength characteristics of the fiber according to the conventional method without adjusting the softening temperature of the cladding glass.

図から明らかなように、この発明方法によるファイバ
は波長1.55μｍで0.18dB/kmと極めて低損失のものであ
る。As is clear from the figure, the fiber according to the present invention has an extremely low loss of 0.18 dB / km at a wavelength of 1.55 μm.

以上この発明の実施例では、クラッドを複数層にな
し、その中の塩素と酸素の残留量を調整した例を示した
が、これに限定されるものでなくフッ素やリン、ゲルマ
ニウムをドープさせても同様の効果を得ることができ
る。In the embodiment of the present invention, the clad is formed into a plurality of layers, and the example in which the residual amounts of chlorine and oxygen in the clad are adjusted has been described.However, the present invention is not limited to this, and fluorine, phosphorus, and germanium may be doped. Can obtain the same effect.

（発明の効果） この発明は、以上のように光ファイバ用のロッドを中
心から外側に向かって順次軟化温度が高くなるようにし
たので、このロッドをファイバ化する際に内部に応力が
残留することがなく、以って低損失のファイバを得るこ
とができる。(Effects of the Invention) In the present invention, as described above, the softening temperature of the optical fiber rod is gradually increased from the center toward the outside, so that when the rod is formed into a fiber, stress remains inside. Thus, a low-loss fiber can be obtained.

【図面の簡単な説明】[Brief description of the drawings]

第１、第２図は、この発明の実施例における一工程を示
す説明図、第３図は、この発明によるファイバの断面方
向の粘度を示す説明図、第４図は、この発明によるファ
イバと従来のファイバの損失波長特性を示すグラフであ
る。 図において、1:ゲルマニアドープコア用ロッド、4:SiO2
ガラス微粒子層、5:石英マッフルチューブ、6:雰囲気ガ
ス供給口。1 and 2 are explanatory views showing one process in an embodiment of the present invention, FIG. 3 is an explanatory view showing a cross-sectional viscosity of a fiber according to the present invention, and FIG. 9 is a graph showing a loss wavelength characteristic of a conventional fiber. In the figure, 1: rod for germania-doped core, 4: SiO 2
Glass fine particle layer, 5: quartz muffle tube, 6: atmosphere gas supply port.

フロントページの続き (72)発明者 磯野 吉哉 千葉県佐倉市六崎1440番地 藤倉電線株 式会社佐倉工場内 (56)参考文献 特開 昭57−47740（ＪＰ，Ａ) 特開 昭63−189809（ＪＰ，Ａ)Continuation of the front page (72) Inventor Yoshiya Isono 1440 Mutsuzaki, Sakura City, Chiba Prefecture Inside the Sakura Plant of Fujikura Electric Cable Co., Ltd. (56) References JP-A-57-47740 (JP, A) JP-A-63-189809 (JP) , A)

Claims (2)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】石英ガラスを主成分としてなる光ファイバ
であって、少なくとも１種類の金属酸化物をドーパント
として含む、石英ガラスよりも屈折率が高くされてな
る、相対的に断面積の小さなコアと、このコアよりも軟
化温度が高く、その屈折率が石英ガラスのそれにほぼ等
しく、相対的に断面積の小さな第１のクラッドと、この
第１のクラッドよりも軟化温度が高く、その屈折率が石
英ガラスのそれにほぼ等しく、その断面積が前記コア及
び第１のクラッドのそれよりも相対的に大きな第２のク
ラッドとからなることを特徴とする光ファイバ。An optical fiber comprising quartz glass as a main component, comprising a core having at least one kind of metal oxide as a dopant and having a higher refractive index than quartz glass and having a relatively small cross-sectional area. And a first cladding having a softening temperature higher than that of the core and a refractive index substantially equal to that of quartz glass and having a relatively small cross-sectional area, and a softening temperature higher than that of the first cladding and a refractive index of the first cladding. Is substantially equal to that of quartz glass, and the cross-sectional area of the core and the second clad are larger than those of the first clad. 【請求項２】ゲルマニウムがドープされた、相対的に小
さな直径のコア用石英ガラスロッドの周りに相対的に薄
くSiO2ガラス微粒子層を堆積させ、次いでこれを陰イオ
ンもしくは酸素雰囲気で透明ガラス化させて相対的に薄
い第１のクラッド層を形成し、さらにその上に相対的に
厚くSiO2ガラス微粒子を堆積させた後、陰イオンもしく
は酸素量が前記第１のクラッド層形成時よりも少量の雰
囲気で透明ガラス化させて前記第１のクラッド層よりも
陰イオンもしくは酸素を少量に含む、前記コア及び第１
のクラッド層よりも相対的に断面積の大きな第２のクラ
ッド層となし、得られた第１、第２のクラッド層を有す
るロッドを線引きすることを特徴とする光ファイバの製
造方法。Wherein the germanium doped, relatively small around the quartz glass rod for a core having a diameter of depositing a relatively thin SiO 2 glass fine particle layer, followed by vitrification in an anion or an oxygen atmosphere so After forming a relatively thin first cladding layer and depositing relatively thick SiO 2 glass fine particles thereon, the amount of anions or oxygen is smaller than that in forming the first cladding layer. The core and the first cladding layer, which are made vitrified in an atmosphere and contain a smaller amount of anions or oxygen than the first cladding layer.
Forming a second clad layer having a relatively larger cross-sectional area than the clad layer described above, and drawing a rod having the obtained first and second clad layers.
JP63232632A 1988-09-19 1988-09-19 Optical fiber and method for manufacturing the same Expired - Lifetime JP2988524B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP63232632A JP2988524B2 (en) 1988-09-19 1988-09-19 Optical fiber and method for manufacturing the same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP63232632A JP2988524B2 (en) 1988-09-19 1988-09-19 Optical fiber and method for manufacturing the same

Publications (2)

Publication Number Publication Date
JPH0281004A JPH0281004A (en) 1990-03-22
JP2988524B2 true JP2988524B2 (en) 1999-12-13

Family

ID=16942354

Family Applications (1)

Application Number Title Priority Date Filing Date
JP63232632A Expired - Lifetime JP2988524B2 (en) 1988-09-19 1988-09-19 Optical fiber and method for manufacturing the same

Country Status (1)

Country Link
JP (1) JP2988524B2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101858732B1 (en) * 2016-09-13 2018-05-16 한국광기술원 optical transmission apparatus of medical endoscope
KR101907154B1 (en) * 2016-05-26 2018-10-11 한국광기술원 passive type polarization scrambler

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001038243A1 (en) * 1999-11-24 2001-05-31 Corning Incorporated Method for radially consolidating a porous optical fiber preform
JP4093553B2 (en) * 2002-08-07 2008-06-04 信越化学工業株式会社 Optical fiber preform, manufacturing method thereof, and optical fiber obtained by drawing the same
JP5144159B2 (en) * 2007-07-26 2013-02-13 パナソニック株式会社 Lifting and drying equipment
US8565566B2 (en) 2011-10-05 2013-10-22 Sumitomo Electric Industries, Ltd. Multi-mode optical fiber
US8565567B2 (en) 2011-11-23 2013-10-22 Sumitomo Electric Industries, Ltd. Multi-mode optical fiber

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4298365A (en) * 1980-07-03 1981-11-03 Corning Glass Works Method of making a soot preform compositional profile
JPS63189809A (en) * 1987-02-02 1988-08-05 Nippon Telegr & Teleph Corp <Ntt> Single mode optical fiber

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101907154B1 (en) * 2016-05-26 2018-10-11 한국광기술원 passive type polarization scrambler
KR101858732B1 (en) * 2016-09-13 2018-05-16 한국광기술원 optical transmission apparatus of medical endoscope

Also Published As

Publication number Publication date
JPH0281004A (en) 1990-03-22

Similar Documents

Publication Publication Date Title
US4243298A (en) High-strength optical preforms and fibers with thin, high-compression outer layers
US5702497A (en) Method of producing an optical fiber preform from a plurality of tubes having different thermal conductivities
US5482525A (en) Method of producing elliptic core type polarization-maintaining optical fiber
JPS5843336B2 (en) Manufacturing method of clad type optical glass fiber
JP2959877B2 (en) Optical fiber manufacturing method
US4664473A (en) Optical fiber formed of MgO--Al2 O3 --SiO2 glass
US4351658A (en) Manufacture of optical fibers
CA1121160A (en) Method of manufacturing optical fibers
JP2988524B2 (en) Optical fiber and method for manufacturing the same
JPS61191543A (en) Quartz base optical fiber
CA1122079A (en) Manufacture of monomode fibers
JPS627130B2 (en)
JP2616087B2 (en) Manufacturing method of elliptical core type polarization maintaining optical fiber
JPS62116902A (en) Wide-band low dispersion optical fiber
JP2800960B2 (en) Viscous matching method of optical fiber and viscous matching optical fiber
JPH02113205A (en) Optical fiber
JPH0557215B2 (en)
JP2770092B2 (en) Radiation-resistant image fiber
JPS6313946B2 (en)
JPH04362603A (en) Low-loss optical fiber
JPH03248103A (en) Optical fiber for image fiber
JPH01270534A (en) Production of optical fiber preform
JPH0425216B2 (en)
JPH06171978A (en) Quartz optical fiber
KR19990015863A (en) Distributed transition single mode fiber with wedge structure

Legal Events

Date Code Title Description
FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20081008

Year of fee payment: 9

EXPY Cancellation because of completion of term