JPS6028325B2 - Manufacturing method of optical fiber end - Google Patents

Description

Translated fromJapanese

【発明の詳細な説明】本発明は半導体レーザ等の光源と光フアィバの高効率結
合のための光フアィバ端部の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an optical fiber end for highly efficient coupling of a light source such as a semiconductor laser and an optical fiber.

光フアィバと半導体レーザとの結合は、光フアィバの指
向角と半導体レーザの指向角があまりにも異りすぎるた
め、高効率な結合は得られにくい。When coupling an optical fiber to a semiconductor laser, it is difficult to achieve highly efficient coupling because the orientation angle of the optical fiber and the orientation angle of the semiconductor laser are too different.

このため従来は光フアィバの端部を加熱、あるいは研磨
によって第１図Ａに示すようなレンズ状に加工していた
。図において１はコア、２はクラッドである。コアとク
ラッドの寸法が、あまり異らないときには、第１図Ａに
示すようにコア部の端部が十分にレンズに凸となるが、
第１図８に示すようにコアの径が小さくなると同一の構
成ではしンズ効果は期待されない。従って半導体レーザ
と光フアィバとの結合効率は大きくならない。従って結
合効率をあげるためにコァと同程度の大きさのレンズを
加工し、光フアィバ端部に接着する方法等が提案されて
いるが、加工がきわめて困難であり、工業性に乏しく、
また接着剤等を用いるため経年変化の恐れがある。本発
明はこれらの欠点を除去するために提案されたもので、
高効率な結合が可能な光フアィバ端部とその製造方法を
提供しようとするもので、以下図面について本発明を詳
細に説明する。For this reason, conventionally, the end of the optical fiber was processed into a lens shape as shown in FIG. 1A by heating or polishing. In the figure, 1 is the core and 2 is the cladding. When the dimensions of the core and cladding are not much different, the end of the core becomes sufficiently convex to the lens as shown in FIG. 1A.
As shown in FIG. 18, when the diameter of the core becomes smaller, no radial effect can be expected with the same configuration. Therefore, the coupling efficiency between the semiconductor laser and the optical fiber does not increase. Therefore, in order to increase the coupling efficiency, methods have been proposed in which a lens of the same size as the core is processed and bonded to the end of the optical fiber, but this method is extremely difficult to process and is not industrially viable.
Also, since adhesives are used, there is a risk of deterioration over time. The present invention has been proposed to eliminate these drawbacks.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is intended to provide an optical fiber end portion capable of highly efficient coupling and a method for manufacturing the same, and the present invention will be described in detail below with reference to the drawings.

第２図は本発明の方法によって作られた端部を示すもの
であって１はコア、２はクラツド、３はコア部で、コア
の端部のみが凸面に形成されている部分を示す。FIG. 2 shows the end portion made by the method of the present invention, where 1 is the core, 2 is the cladding, and 3 is the core portion, where only the end portion of the core is formed into a convex surface.

又コアの端部の媒質はコアを加工したものであるから、
コアと同煤質で連続している。第３図はコアの端部を凸
面に形成するための製造方法を示す。Also, since the medium at the end of the core is a processed core,
It has the same soot quality as the core and is continuous. FIG. 3 shows a manufacturing method for forming the end of the core into a convex surface.

４，４′は加熱のための放電電極で、コアの端部の両側
に配置される。4 and 4' are discharge electrodes for heating, which are arranged on both sides of the end of the core.

５は電源で約４ＫＶである。5 is a power supply of approximately 4KV.

コアの融点はクラツドの融点に比べて１００ｑｏ以上低
いため、クラッド部２′を加熱すると、その時点でコア
部１′は融点に達しているため、クラツド部の表面張力
によりクラツドがわずかに細り、そのためコア部の一部
が外に押し出され、３で示されている凸面部を形成する
。この時点で放電加熱を停止する。コァがクラッドより
融点を低くするためには、例えばクラッドを熔融石英で
、コアをリン，ゲルマニウム等をドープした熔融石英と
すればよい。実験例としてコア径６０Ａｍのリンをドー
プした多モード光フアイバを用いた場合、様面の凸面部
の曲率半径は約１００ｒｍとなり、十分なしンズ効果が
観測された。なおコア部とクラッド部との融点の差はほ
ぼ１００ｑｏ以上あることが望ましい。なお１００℃未
満の場合はコア部の溶融が不十分であり、実用上好まし
くない。叙上のように本発明は、凸面部がコアと同一材
質から成っているため、経時変化もなく、高効率な結合
が期待でき、また製造方法もきわめて容易である。The melting point of the core is more than 100 qo lower than the melting point of the cladding, so when the cladding part 2' is heated, the core part 1' has reached its melting point at that point, so the cladding becomes slightly thinner due to the surface tension of the cladding part. Therefore, a portion of the core portion is pushed out to form a convex portion shown at 3. At this point, discharge heating is stopped. In order to make the melting point of the core lower than that of the cladding, the cladding may be made of fused silica, and the core may be made of fused silica doped with phosphorus, germanium, or the like. When a phosphorus-doped multimode optical fiber with a core diameter of 60 Am was used as an experimental example, the radius of curvature of the convex portion of the modulus was approximately 100 rm, and a sufficient lens effect was observed. Note that it is desirable that the difference in melting point between the core portion and the cladding portion be approximately 100 qo or more. Note that if the temperature is less than 100°C, the core portion will not be sufficiently melted, which is not preferred in practice. As described above, in the present invention, since the convex portion is made of the same material as the core, there is no change over time, highly efficient coupling can be expected, and the manufacturing method is extremely easy.

又本発明はコア径の細い単一モード光フアィバの端面形
成手段としても有効である。The present invention is also effective as a means for forming an end face of a single mode optical fiber having a small core diameter.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図Ａ，Ｂは従来の光ファィバ端部、第２図は本発明
の方法によって作られた光フアィバ端部の断面図、第３
図は製造方法を示す。１，１′……コア、２，２′……クラツド、３…・・・
凸面部、４，４′・・・・・・電極、５・・…・電源。第１図第２図第３図1A and 1B are conventional optical fiber ends, FIG. 2 is a sectional view of an optical fiber end made by the method of the present invention, and FIG.
The figure shows the manufacturing method. 1, 1'... core, 2, 2'... clad, 3...
Convex portion, 4, 4'...electrode, 5...power supply. Figure 1 Figure 2 Figure 3

Claims (1)

Translated fromJapanese

【特許請求の範囲】[Claims]１ コア部の融点がクラツド部の融点より１００℃以上
低い光フアイバの平滑端面附近を、該クラツド部が熔融
する程度に加熱し、クラツド部の表面張力によりクラツ
ド部の先端を細らせ、該コア部を前記の平滑端面より押
し出し、凸面に形成することを特徴とする光フアイバ端
部の製造方法。1. Heat the vicinity of the smooth end face of an optical fiber, where the melting point of the core part is 100°C or more lower than the melting point of the cladding part, to such an extent that the cladding part melts, and the surface tension of the cladding part causes the tip of the cladding part to become thinner. A method for manufacturing an optical fiber end, comprising extruding the core from the smooth end surface to form a convex surface.