JPH05323143A - Optical fiber for illumination light transmission - Google Patents
Optical fiber for illumination light transmissionInfo
- Publication number
- JPH05323143A JPH05323143A JP4156209A JP15620992A JPH05323143A JP H05323143 A JPH05323143 A JP H05323143A JP 4156209 A JP4156209 A JP 4156209A JP 15620992 A JP15620992 A JP 15620992A JP H05323143 A JPH05323143 A JP H05323143A
- Authority
- JP
- Japan
- Prior art keywords
- refractive index
- core
- optical fiber
- diameter
- illumination light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Light Guides In General And Applications Therefor (AREA)
- Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
Abstract
(57)【要約】
【目的】 出射速度パターンが均一な照明伝送用光ファ
イバを提供する。
【構成】 この発明の照明伝送用光ファイバは、一定の
屈折率ｎ1 を有する第１の部分と、その周りに形成され
た屈折率がｎ1 からそれよりも小さなｎ2 に低減する第
２部分からなるコアと、この第２部分の周りに形成され
た屈折率がｎ2 よりも小さな屈折率がｎ3 のクラッドと
ら構成されている。そして、コアの中心をなす第１の部
分の直径はコア径の５０〜９０％、好ましくは６０〜８
０％とされており、第１の部分の屈折率ｎ1 と第２部分
の屈折率ｎ2 との比屈折率差は０．２〜０．６％、第１
の部分の屈折率ｎ1 とクラッドの屈折率のｎ3 との比屈
折率差は０．５〜１．９％とされている。この構成とす
ることにより、出射光強度パターンは均一になる。
(57) [Summary] [Objective] To provide an optical fiber for illumination transmission with a uniform emission velocity pattern. According to the illumination transmission optical fiber of the present invention, a first portion having a constant refractive index n 1 and a second portion formed around the first portion are reduced from n 1 to n 2 which is smaller than that. It is composed of a core consisting of a part and a clad formed around the second part and having a refractive index n 3 smaller than n 2 . The diameter of the first portion forming the center of the core is 50 to 90% of the core diameter, preferably 60 to 8
0%, and the relative refractive index difference between the refractive index n 1 of the first portion and the refractive index n 2 of the second portion is 0.2 to 0.6%.
Relative refractive index difference between the refractive index n 1 and n 3 of the refractive index of the cladding portion is a 0.5 to 1.9%. With this configuration, the emitted light intensity pattern becomes uniform.
Description
【０００１】[0001]
【産業上の利用分野】この発明は、照明光伝送用光ファ
イバに関するもので、特に出射光の強度分布が均一な照
明光伝送用光ファイバに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber for transmitting illumination light, and more particularly to an optical fiber for transmitting illumination light having a uniform intensity distribution of emitted light.
【０００２】[0002]
【従来の技術】照明光伝送用光ファイバには、コア径の
大きないわゆる大口径で、その屈折率分布がステップ
型、もしくはグレーデッド型のものが使用されている。
ところで、光ファイバの出射光の強度分布は、その長さ
が数ｋｍと長いときにはその屈折率分布とほぼ同一をな
す。ところが、照明光伝送用光ファイバの出射光の強度
分布を見ると、その屈折率分布が前述のようにステップ
型、もしくはグレーデッド型であるにもかかわらず屈折
率分布と同一形状をなさず、また均一であるとも言いが
たい。その理由は、使用されるファイバ長が数十ｍ以
下、中には数ｍといった短いものが多く、このような長
さが短いと不要光が減衰されずにそのまま伝送されるか
らである。特にステップ型の場合、サーキュラーモード
（コア中を螺旋状に伝搬するモード）が多く残り、出射
パターンがドーナッツ状になってしまうためである。な
お、グレーデッド型の場合、このようなサーキュラーモ
ードの問題はないが本質的に伝搬光の出射パターンは分
布を有しており均一ではない。2. Description of the Related Art As an optical fiber for transmitting illumination light, a so-called large-diameter optical fiber having a large core diameter and a refractive index distribution of step type or graded type is used.
By the way, the intensity distribution of the light emitted from the optical fiber is almost the same as the refractive index distribution when the length is as long as several km. However, when looking at the intensity distribution of the emitted light of the optical fiber for illumination light transmission, the refractive index distribution does not have the same shape as the refractive index distribution, even if it is a step type or a graded type as described above, It is also hard to say that they are uniform. The reason is that the fiber used has a short fiber length of several tens of meters or less, some of which are several meters, and if the fiber length is short, unnecessary light is transmitted as it is without being attenuated. This is because, especially in the case of the step type, a large number of circular modes (modes of propagating spirally in the core) remain and the emission pattern becomes a donut shape. Incidentally, in the case of the graded type, there is no problem of such a circular mode, but the emission pattern of the propagating light essentially has a distribution and is not uniform.
【０００３】[0003]
【発明が解決しようとする課題】然しながら、レーザ光
で材料に一定の深さの溝を加工するといった観点から、
照明光伝送用光ファイバにおいて出射光の強度分布が一
定のものが要求されるようになり、従来のステップ型、
グレーデッド型の屈折率分布のものでは対応しきれない
ことから、新たな屈折率分布のファイバ構造が検討され
ていた。この発明者等は、新たな屈折率分布のファイバ
構造を開発するに当たって、従来のステップ型、グレー
デッド型の屈折率分布の光ファイバの出射パターンにつ
いてさらに解析を行なったところ、ステップ型の場合、
前述したサーキュラーモードは必ず発生するが、このモ
ード自身の損失は大きく、光ファイバの長さが長いと減
衰して問題にならないこと、グレーデッド型の場合、サ
ーキュラモードは外に洩れて減衰するか、正常モードに
変換されてファイバ長が短くても殆ど問題にならないと
いう知見を得、両者の中間の屈折率分布であれば出射強
度のパターンが均一になるのではないかとの推論に達し
た。However, from the viewpoint of processing a groove having a certain depth in a material with a laser beam,
In the optical fiber for illumination light transmission, the intensity distribution of emitted light is required to be constant, and the conventional step type,
Since a graded type refractive index profile cannot be used, a fiber structure with a new refractive index profile has been studied. The present inventors, in developing a fiber structure having a new refractive index distribution, further analyzed the exit pattern of the conventional step type, graded type refractive index distribution optical fiber, and in the case of the step type,
The circular mode mentioned above always occurs, but the loss of this mode itself is large, and it does not matter if the length of the optical fiber is long. Then, we obtained the knowledge that there is almost no problem even if the fiber length is converted to the normal mode and the fiber length is short, and we have inferred that the pattern of the emission intensity may be uniform if the refractive index distribution is in between.
【０００４】[0004]
【課題を解決するための手段】この発明は、以上の観点
からなされたもので、その特徴とする請求項１記載の発
明は、一定の屈折率ｎ1 を有する第１の部分と、この第
１の部分の周りに形成された、その屈折率が屈折率ｎ1
からそれよりも小さな屈折率ｎ2 に漸減する第２の部分
とからなるコアと、このコアの周りに形成された、屈折
率が前記屈折率ｎ2 よりも小さな屈折率ｎ3 を有するク
ラッドとからなる照明光伝送用光ファイバにある。ま
た、その特徴とする請求項１記載の発明は、コアをなす
第１の部分の直径がコア径の５０〜９０％であり、かつ
第１の部分の屈折率ｎ1 と第２の部分の屈折率ｎ2 との
比屈折率差Δが０．２〜０．６％であり、さらにコアの
第１の部分の屈折率ｎ1 とクラッドの屈折率ｎ3 との比
屈折率差Δが少なくとも０．５％である請求項１記載の
照明光伝送用光ファイバにある。The present invention has been made from the above point of view. The invention according to claim 1 is characterized by a first portion having a constant refractive index n 1 and The refractive index formed around the portion 1 has a refractive index n 1
From a core consisting of a second portion of decreasing it into smaller refractive index n 2 Also, the core is formed around a, a cladding refractive index has a refractive index n 3 than the refractive index n 2 An optical fiber for transmitting illumination light. Further, the invention according to claim 1 characterized in that the diameter of the first portion forming the core is 50 to 90% of the core diameter, and the refractive index n 1 of the first portion and the second portion The relative refractive index difference Δ with the refractive index n 2 is 0.2 to 0.6%, and the relative refractive index difference Δ between the refractive index n 1 of the first portion of the core and the refractive index n 3 of the clad is It is at least 0.5%. The optical fiber for transmitting illumination light according to claim 1.
【０００５】[0005]
【作用】コアの屈折率分布を、中心の第１の部分をステ
ップ型として、その周りの第２の部分をグレーテッド型
とすることにより、中心の第１の部分で出射強度のパタ
ーンを本質的に均一なステップ型とするとともに、ステ
ップ型故に生じるサーキュラーモードを第２の部分で正
常モードに変換し、全体として均一な出射強度パターン
とする。The refractive index distribution of the core is formed so that the first portion in the center is the step type and the second portion around it is the graded type, so that the pattern of the emission intensity is essentially formed in the first portion in the center. And a circular mode that is uniform due to the step type is converted into a normal mode in the second portion to form a uniform emission intensity pattern as a whole.
【０００６】[0006]
【実施例１】図１は、この発明の照明光伝送用石英系フ
ァイバの断面図、図２はその屈折率分布図である。図に
おいて、１はコアの中心をなす第１の部分で、例えばＧ
ｅＯ2 ーＳｉＯ2 からなる一定の屈折率ｎ1 を有してい
る。２は第１の部分の周りに形成された、コアの一部を
なす第２の部分で、第１の部分１と同様にＧｅＯ2 ーＳ
ｉＯ2 からなり、その屈折率はＧｅ量の調整により屈折
率ｎ1 から次第に漸減して屈折率ｎ2 に至っている。な
お、コアの一部をなす第１の部分の直径のコア径に対す
る比率は５０〜９０％、好ましくは６０〜８０％とされ
る。さらに、屈折率ｎ1 と屈折率ｎ2 との比屈折率差は
０．２〜０．６％とされる。３はクラッドで、例えばＦ
ーＳｉＯ2 からなり、その屈折率は屈折率ｎ2 よりも小
さいｎ3 であって、その純粋石英ガラスとの比屈折率差
Δ＝−０．３〜−１．３％、コアの第１の部分の屈折率
ｎ1 との比屈折率差Δ＝０．５〜１．９％とされてい
る。EXAMPLE 1 FIG. 1 is a sectional view of a silica fiber for transmitting illumination light according to the present invention, and FIG. 2 is a refractive index distribution diagram thereof. In the figure, 1 is a first portion which forms the center of the core, for example G
eO 2 chromatography has a constant refractive index n 1 made of SiO 2. Reference numeral 2 is a second portion formed around the first portion and forming a part of the core. Like the first portion 1, GeO 2 --S
It is made of iO 2 , and its refractive index gradually decreases from the refractive index n 1 to the refractive index n 2 by adjusting the Ge amount. The ratio of the diameter of the first portion forming a part of the core to the core diameter is 50 to 90%, preferably 60 to 80%. Further, the relative refractive index difference between the refractive index n 1 and the refractive index n 2 is 0.2 to 0.6%. 3 is a clad, for example, F
-SiO 2 , its refractive index is n 3 which is smaller than the refractive index n 2 , and its relative refractive index difference Δ = −0.3 to −1.3% with respect to the pure quartz glass, The relative refractive index difference Δ with respect to the refractive index n 1 of the part is 0.5 to 1.9%.
【０００７】[0007]
【具体例】先ず、ＶＡＤ法により直径φ２０ｍｍ，長さ
ｌ７００ｍｍのコア母材を作製した。第１の部分はＧｅ
Ｏ2 ーＳｉＯ2 ガラスで構成し、その直径は１２ｍｍで
コア径の６０％、屈折率は純粋石英のそれとの比較で比
屈折率差Δ＝約０．５％で一定とした。第２の部分は第
１の部分同様にＧｅＯ2 ーＳｉＯ2 ガラスとしたが、そ
の直径は２０ｍｍとし、コア径の６０％から最外周の１
００％に向かってＧｅ量を漸減して、屈折率を純粋石英
のそれとの比較で比屈折率差Δ＝約０．５〜０．１％に
直線的に変化させた。このコア部材の周りにプラズマ外
付け法によりＦ−ＳｉＯ2 ガラスを堆積して純粋石英ガ
ラスとの比屈折率差Δ＝約−１％のクラッド部を形成し
た。仕上がり寸法は、外径φ：２５ｍｍ、長さｌ：約６
００ｍｍとした。この母材をコア径４００μｍ、ファイ
バ径５００μｍに線引きし、その上に被覆材としてシリ
コーン樹脂をコーティングして外径７００μｍとした。
このファイバにＹＡＧレーザを伝送させたところ、出射
パターンは図３に示すようにほぼ一定強度のパターンで
あった。Concrete Example First, a core preform having a diameter of 20 mm and a length of 1700 mm was manufactured by the VAD method. The first part is Ge
It was made of O 2 —SiO 2 glass, the diameter of which was 12 mm and 60% of the core diameter, and the refractive index was constant at a relative refractive index difference Δ = about 0.5% as compared with that of pure quartz. The second part was made of GeO 2 -SiO 2 glass as in the first part, but its diameter was 20 mm, and it was 60% of the core diameter to 1 of the outermost circumference.
The Ge amount was gradually reduced toward 00%, and the refractive index was linearly changed to a relative refractive index difference Δ = about 0.5 to 0.1% in comparison with that of pure quartz. F-SiO 2 glass was deposited around this core member by a plasma external attachment method to form a clad portion having a relative refractive index difference Δ from pure silica glass of about −1%. Finished dimensions: outer diameter φ: 25 mm, length l: approx. 6
It was set to 00 mm. This base material was drawn to have a core diameter of 400 μm and a fiber diameter of 500 μm, and a silicone resin was coated thereon to form an outer diameter of 700 μm.
When a YAG laser was transmitted to this fiber, the emission pattern was a pattern of substantially constant intensity as shown in FIG.
【０００８】[0008]
【発明の効果】この発明による照明伝送用光ファイバ
は、コアが中心をなす第１の部分とその周囲の第２の部
分からなり、しかも第１の部分の屈折率は一定で、第２
の部分の屈折率はこの第１の部分の屈折率と等しい屈折
率からそれよりも小さい屈折率に向かって次第に減少す
る屈折率分布を有し、さらにその外側に屈折率分布が第
２の部分の最小屈折率よりも小さな屈折率のクラッドを
設けた構造であるので、伝送光の出射強度のパターンを
均一にできるという効果を奏する。The optical fiber for illumination transmission according to the present invention comprises a first portion having a core as a center and a second portion around the core, and the refractive index of the first portion is constant.
Has a refractive index profile that gradually decreases from a refractive index equal to the refractive index of the first part toward a smaller refractive index, and further outside thereof has a refractive index profile. Since the clad having a refractive index smaller than the minimum refractive index is provided, the effect that the pattern of the emission intensity of the transmitted light can be made uniform can be obtained.
【図１】この発明による照明光伝送用光ファイバの断面
図。FIG. 1 is a sectional view of an optical fiber for transmitting illumination light according to the present invention.
【図２】図１の照明光伝送用光ファイバの屈折率分布
図。FIG. 2 is a refractive index distribution diagram of the illumination light transmission optical fiber of FIG.
【図３】図１の照明光伝送用光ファイバの出射強度分布
図。FIG. 3 is an emission intensity distribution chart of the optical fiber for transmitting illumination light in FIG.
１ コアの中心をなす第１の部分 ２ 第１の部分の周りに形成された、コアの一部をなす
第２の部分 ３ クラッド1 1st part which forms the center of the core 2 2nd part which forms a part of the core formed around the 1st part 3 Cladding
───────────────────────────────────────────────────── フロントページの続き (72)発明者 妻沼 孝司 千葉県佐倉市六崎1440番地 藤倉電線株式 会社佐倉工場内 (72)発明者 真田 和夫 千葉県佐倉市六崎1440番地 藤倉電線株式 会社佐倉工場内 (72)発明者 鳥谷 智晶 千葉県佐倉市六崎1440番地 藤倉電線株式 会社佐倉工場内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Tamanuma 1440 Rokuzaki, Sakura City, Chiba Prefecture, Fujikura Cable Co., Ltd.Sakura Factory (72) Inventor, Kazuo Sanada, 1440, Rokkazaki Sakura City, Chiba, Fujikura Cable Co., Ltd.Sakura Factory ( 72) Inventor Tomoaki Toritani 1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Electric Co., Ltd.Sakura Factory
Claims (2)
と、この第１の部分の周りに形成された、その屈折率が
屈折率ｎ1 からそれよりも小さな屈折率ｎ2 に漸減する
第２の部分とからなるコアと、このコアの周りに形成さ
れた、屈折率が前記屈折率ｎ2 よりも小さな屈折率ｎ3
を有するクラッドとからなることを特徴とする照明光伝
送用光ファイバ。 1. A first portion having a constant refractive index n 1, and a refractive index formed around the first portion, the refractive index of which decreases from the refractive index n 1 to a smaller refractive index n 2 . And a refractive index n 3 formed around the core and having a refractive index smaller than the refractive index n 2
An optical fiber for illuminating light transmission, comprising: a clad having:
５０〜９０％であり、かつ第１の部分の屈折率ｎ1 と第
２の部分の屈折率ｎ2 との比屈折率差Δが０．２〜０．
６％であり、さらにコアの第１の部分の屈折率ｎ1 とク
ラッドの屈折率ｎ3 との比屈折率差Δが少なくとも０．
５％であることを特徴とする請求項１記載の照明光伝送
用光ファイバ。2. The diameter of the first portion forming the core is 50 to 90% of the core diameter, and the relative refractive index between the refractive index n 1 of the first portion and the refractive index n 2 of the second portion. The difference Δ is 0.2 to 0.
6%, and the relative refractive index difference Δ between the refractive index n 1 of the first portion of the core and the refractive index n 3 of the clad is at least 0.
It is 5%, The optical fiber for illumination light transmission of Claim 1 characterized by the above-mentioned.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04156209A JP3142955B2 (en) | 1992-05-25 | 1992-05-25 | Optical fiber for illumination light transmission for laser beam machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04156209A JP3142955B2 (en) | 1992-05-25 | 1992-05-25 | Optical fiber for illumination light transmission for laser beam machine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05323143A true JPH05323143A (en) | 1993-12-07 |
| JP3142955B2 JP3142955B2 (en) | 2001-03-07 |
Family
ID=15622753
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04156209A Expired - Lifetime JP3142955B2 (en) | 1992-05-25 | 1992-05-25 | Optical fiber for illumination light transmission for laser beam machine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3142955B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5940567A (en) * | 1998-02-20 | 1999-08-17 | Photon-X, Inc. | Optical fibers having an inner core and an outer core |
| WO2005022218A1 (en) * | 2003-08-29 | 2005-03-10 | Sumitomo Electric Industries, Ltd. | Optical part, optical part producing method and optical system |
| CN114859459A (en) * | 2022-04-27 | 2022-08-05 | 长飞光坊(武汉)科技有限公司 | Special optical fiber for realizing flat-top energy distribution and controlling light beam quality |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2754297B2 (en) | 1991-09-30 | 1998-05-20 | 株式会社フジクラ | Optical fiber for laser treatment |
-
1992
- 1992-05-25 JP JP04156209A patent/JP3142955B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5940567A (en) * | 1998-02-20 | 1999-08-17 | Photon-X, Inc. | Optical fibers having an inner core and an outer core |
| WO2005022218A1 (en) * | 2003-08-29 | 2005-03-10 | Sumitomo Electric Industries, Ltd. | Optical part, optical part producing method and optical system |
| CN114859459A (en) * | 2022-04-27 | 2022-08-05 | 长飞光坊(武汉)科技有限公司 | Special optical fiber for realizing flat-top energy distribution and controlling light beam quality |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3142955B2 (en) | 2001-03-07 |
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