JPS6035839B2 - Optical fiber for fiber Brahman laser - Google Patents
Optical fiber for fiber Brahman laserInfo
- Publication number
- JPS6035839B2 JPS6035839B2 JP54147030A JP14703079A JPS6035839B2 JP S6035839 B2 JPS6035839 B2 JP S6035839B2 JP 54147030 A JP54147030 A JP 54147030A JP 14703079 A JP14703079 A JP 14703079A JP S6035839 B2 JPS6035839 B2 JP S6035839B2
- Authority
- JP
- Japan
- Prior art keywords
- fiber
- laser
- optical fiber
- light
- core
- 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
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/30—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
- H01S3/302—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects in an optical fibre
Description
【発明の詳細な説明】
本発明は、ファイバラマソレーザー用光フアィバ、特に
ファイバラマンレーザー用のし一ザー媒質として利得の
大きい高純度ガラス光フアィバに関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber for a fiber Raman laser, and particularly to a high-purity glass optical fiber having a high gain as a laser medium for a fiber Raman laser.
ファイバラマンレーザーは、高出力レーザ、たとえばＮ
ｄ：ＹＡＧレーザーの光をフアィバ状のレーザー煤質中
に入射し、煤質中での誘導ラマン散乱効果を用いて入射
光と異なる波長のレーザー光を取り出すものである。Fiber Raman lasers are high-power lasers, such as N
d: YAG laser light is input into a fiber-shaped laser soot, and the stimulated Raman scattering effect in the soot is used to extract laser light with a wavelength different from that of the incident light.
現在までに得られている種々のし−ザーの波長は限られ
たものであるが、ファイバラマンレーザ−を用いれば今
までにない波長のレーザー光を取り出せるため、広範な
応用が期待される。フアィバ状媒質中での誘導ラマン散
乱を起こし易くするためには、既に知られているように
、コア断面積が小さく、光損失の４・さな十分長いフア
ィバに高出力のレーザー光を入射する必要がある。さら
にフアィバ状媒質がラマン散乱係数の大きな物質である
ことも必要とされる。従来、フアィバ状のレーザー煤質
としては適当なものが存在しなかったが、最近になって
、光損失が小さいことに着目して、光通信用に開発され
たシリカガラス光フアィバが用いられるようになった。
この光通信用ガラスフアイバは、通常シリカよりわずか
に屈折率の高い直径数〜数十仏ｍのコア部とシリカから
成るクラッド部とを有するもので、不純物の極めて少な
いものにあっては光損失を１船／物以下にすることがで
きる。しかしながら、従来は光通信用ガラスフアィバの
低損失性のみを利用するに留まり、ファイバラマンレー
ザー用煤質として最適なガラス組成についての検討はな
されておらず、フアィバへの入射光強度を強くすること
によって誘導ラマン光を強くすることが考えられてきた
ので、装置の大型化、高価格化が避けられなかった。Although the wavelengths of the various lasers that have been obtained to date are limited, fiber Raman lasers can be used to extract laser light of unprecedented wavelengths, and are expected to have a wide range of applications. As is already known, in order to facilitate stimulated Raman scattering in a fiber-like medium, a high-power laser beam is incident on a fiber with a small core cross-sectional area and a sufficiently long fiber with a small optical loss. There is a need. Furthermore, the fibrous medium is also required to be a material with a large Raman scattering coefficient. In the past, there was no suitable fiber-like laser soot material, but recently, silica glass optical fibers developed for optical communications have been used, focusing on their low optical loss. Became.
This glass fiber for optical communication usually has a core part with a diameter of several to several tens of meters, which has a slightly higher refractive index than silica, and a cladding part made of silica. can be reduced to less than 1 ship/object. However, in the past, only the low loss properties of glass fibers for optical communication have been utilized, and no study has been made on the optimal glass composition as soot material for fiber Raman lasers. Consideration has been given to increasing the intensity of stimulated Raman light, which inevitably leads to larger and more expensive equipment.
本発明は前述した現状に鑑みてなされたもので、その目
的は光損失が低く、しかも誘導ラマン散乱効率の大きな
し一ザー媒質としてのガラスファイバを提供することに
ある。The present invention has been made in view of the above-mentioned current situation, and its object is to provide a glass fiber as a laser medium with low optical loss and high stimulated Raman scattering efficiency.
高純度のＳｉ０２ガラスを主成分とし、屈折率制御のた
め蛇０２，Ｐ２０５，Ｂ２０３を少量添加した光フアィ
バについては、遷移金属不純物および残留ＯＨ基を極度
に低減化することにより光損失が１紙／紘以下のものが
既に得られており、ファイバラマンレーザー煤質として
もＳｉ０２ガラスを主成分とする光フアィバを利用する
ことが望ましい。Optical fibers that are mainly composed of high-purity Si02 glass and doped with small amounts of Snake02, P205, and B203 to control the refractive index have a light loss of one paper by extremely reducing transition metal impurities and residual OH groups. /Hiro and below have already been obtained, and it is desirable to use an optical fiber whose main component is Si02 glass as a fiber Raman laser soot material.
そこで、本発明では、本質的に光損失の小さくなるガラ
ス組成としてＳｉ０２一Ｐ２Ｑ系あるいはＳｉＱ−Ｐ２
Ｑ−Ｑ０２系を用いて光通信用極低損失光フアィバと同
程度の低損失化を可能とする。すなわち、本発明光フア
ィバは、実質的に高純度のＳ；０２およびＰ２Ｑによっ
て、屈折率の高いコアおよびコアより屈折率の低いクラ
ッドを形成し、しかも上述のコアのＰ２０５の含有量を
後述するように１０モル％以上となした、ファイバラマ
ンレーザー用のし‐ザー媒質として用いられる単一モー
ド光フアイバである。誘導ラマン散乱光強度の大きさの
目安となるラマン散乱係数に関しては、Ｇｅ０２ガラス
、Ｐ２０５ガラスの方がＳｉＱガラスに比し数倍大きい
ことが知られている。Therefore, in the present invention, Si02-P2Q system or SiQ-P2 system is used as a glass composition that essentially reduces optical loss.
Using the Q-Q02 system, it is possible to achieve a loss comparable to that of ultra-low loss optical fibers for optical communications. That is, the optical fiber of the present invention has a core with a high refractive index and a cladding with a lower refractive index than the core made of substantially high-purity S;02 and P2Q, and the content of P205 in the core is described below. This single mode optical fiber is used as a laser medium for fiber Raman lasers and has a content of 10 mol % or more. Regarding the Raman scattering coefficient, which is a measure of the intensity of stimulated Raman scattered light, it is known that Ge02 glass and P205 glass are several times larger than SiQ glass.
Ｓｉ０２−ＣＣ０２ガラスおよびＳｉ０２一Ｐ２Ｑガラ
スの組成とラマン散乱係数の関係はそれぞれ第１図およ
び第２図に示してある。前者については第１図に示すよ
うに、Ｓｉ０２のラマン散乱効果（入射光より４４０肌
‐１だけエネルギーの小さい光を励起する）を示す強度
特性１と蛇０２のラマン散乱効果（入射光より４２５仇
‐１だけエネルギーの小さい光を励起する）を示す強度
特性２の両方が重ね合わされ、Ｑ０２成分の増加ととも
にラマン散乱係数は大きくなる。また、後者については
、第２図に示すように、Ｐ２０５のラマン散乱効果（入
射光より１３２０の‐１だけエネルギーの４・さな光を
励起する）を示す強度特性３はＰ２０５成分の増加とと
に大きくなる。Ｐ２０５のラマン散乱効果（特性３）は
、Ｓｉ０２や蛇０２の場合（特性１，２）に比し入射光
と励起光の波長間隔が丁度３倍大きいため、本発明によ
れば従来のＳｉ０２コア光フアィバに比し幅広い波長城
において強い励起光を得ることが可能である。この場合
Ｐ２４の添加量が１０モル％以下であると、特性の改善
は少な過ぎて望ましくない。また、本発明において、Ｓ
ｉ０２−Ｐ２０５ガラスにＱ０２を添加すれば、４４０
肌‐１付近のラマン散乱効率を大きくすることができる
。この場合２０モル％より多量の快０２添加は、Ｗ０２
の揮散により精密な屈折率分布形成が困難となり望まし
くない。さらに、入射光を微小面積に集中させるため、
およびパルス歪の小さな出射光を得るためには、単一モ
ード条件、すなわち２．４０５＝空ノ（ｎ・）２‐帆
を満たす単一モード光フアィバであることが望ましい。The relationship between the composition and Raman scattering coefficient of Si02-CC02 glass and Si02-P2Q glass is shown in FIGS. 1 and 2, respectively. Regarding the former, as shown in Fig. 1, intensity characteristic 1 shows the Raman scattering effect of Si02 (excites light with energy smaller than the incident light by 440 skin-1) and Raman scattering effect of Snake 02 (excites light with energy smaller than the incident light by 425 skin). Intensity characteristics 2 (exciting light with lower energy by -1) are superimposed, and the Raman scattering coefficient increases as the Q02 component increases. Regarding the latter, as shown in Figure 2, intensity characteristic 3, which shows the Raman scattering effect of P205 (excites 4-small light with energy 1320 -1 more than the incident light), is due to an increase in the P205 component. It gets bigger. The Raman scattering effect of P205 (characteristic 3) is due to the fact that the wavelength interval between the incident light and the excitation light is exactly three times larger than that of Si02 and Snake 02 (characteristics 1 and 2). It is possible to obtain strong excitation light over a wider range of wavelengths than with optical fibers. In this case, if the amount of P24 added is less than 10 mol %, the improvement in properties will be too small, which is not desirable. Furthermore, in the present invention, S
If Q02 is added to i02-P205 glass, 440
Raman scattering efficiency near the skin-1 can be increased. In this case, the addition of more than 20 mol% of Kai-02 is W02
This volatilization makes it difficult to form a precise refractive index distribution, which is undesirable. Furthermore, in order to concentrate the incident light on a small area,
In order to obtain output light with small pulse distortion, it is desirable to use a single mode optical fiber that satisfies the single mode condition, that is, 2.405=empty(n·)2−sail.
ここで、＾＝光の波長、ａ＝コア半径、ｎ，＝コアの屈
折率、ｎ２＝クラッドの屈折率である。コア径２ａを数
山ｍとするとき、コアとクラッドの比屈折率差（ご二言
２）はｏ‐２〜０‐５％程度と極めて小さいので、ドー
パントを添加してラマン散乱効率の向上を図るためには
、屈折率増加効果の小さいドーパントＰ２Ｑの方が有利
である。次に本発明を実施例について説明するが、本発
明はこれら実施例により何ら限定されるものではない。
実施例 １コアはＳｉ０２８０モル％およびＰ２４２０
モル％の組成から成り、クラッドはＳｉ０２９０モル％
およびＰ２ＱＩＯモル％の組成から成る光フアィバを作
製した。Here, ^=wavelength of light, a=core radius, n,=refractive index of the core, and n2=refractive index of the cladding. When the core diameter 2a is several m, the relative refractive index difference between the core and the cladding (two words 2) is extremely small, about 0-2 to 0-5%, so dopants can be added to improve Raman scattering efficiency. In order to achieve this, the dopant P2Q, which has a small refractive index increasing effect, is more advantageous. Next, the present invention will be explained with reference to Examples, but the present invention is not limited to these Examples in any way.
Example 1 Core is Si0280 mol% and P2420
Composition of mol%, cladding is Si0290 mol%
An optical fiber having a composition of mol % of P2QIO and P2QIO was fabricated.
この場合にコアの屈折率幻，＝１．４７１０クラツドの
屈折率い＝１．４６５０であり、コア径２ａは６〃ｍ、
クラッド外径は１２５ムｍであった。実施例１の光フア
ィバは１．１仏ｍ以上の波長が上述した単一モード条件
を満たしている。比較例 １
コァはＳｉ０２の組成から成り、クラッドはＳｉ０２９
３モル％およびＢ２０３７モル％の組成から成る光フア
ィバを作製した。In this case, the refractive index of the core is 1.4710, the refractive index of the cladding is 1.4650, the core diameter 2a is 6 m,
The outer diameter of the cladding was 125 mm. In the optical fiber of Example 1, a wavelength of 1.1 fm or more satisfies the above-mentioned single mode condition. Comparative Example 1 The core is composed of Si02 and the cladding is Si029.
An optical fiber having a composition of 3 mol% of B20 and 37 mol% of B20 was produced.
コア外径は７仏ｍであり１．１仏ｍ以上で単一モード条
件を満たしている。実施例１と比較例１で得た光フアィ
バに、それぞれ１．０６４ムｍのＮｄ：ＹＡＧレーザー
の光を入射した場合に誘導ラマン散乱により発生した光
のスべクトルを第３図および第４図に示す。Ｎｄ：ＹＡ
Ｇレーザ−はモードロック（１０瓜ＭＨＺ）とＱスイッ
チ（５００ＨＺ）を行ない約５００Ｗのパルス光を発生
しているものとする。第３図に示されているように、実
施例１の光フアイバからは、出射光スペクトル４に示す
ように、１．２４ｒｍ以上の長波長においても強い光を
発生させることができた。一方、比較例１の光フアィバ
から発生したラマン光は、第４図の出射光スペクトル５
に示すように、長波長側で単調に減少し、１．３山ｍ以
上では強い光は得られなかった。実施例 ２
コアはＳｉ０２７８モレ％，Ｐ２０５１５モル％，Ｃｅ
０２７モル％の組成から成り、クラッドはＳｉ０２機モ
ル％，Ｐ２０５５モル％，Ｇｅ０２７モル％の組成から
成る光フアィバを作製した。The outer diameter of the core is 7 French m, and is 1.1 French m or more, which satisfies the single mode condition. Figures 3 and 4 show the spectrum of light generated by stimulated Raman scattering when 1.064 mm Nd:YAG laser light was incident on the optical fibers obtained in Example 1 and Comparative Example 1, respectively. As shown in the figure. Nd:YA
It is assumed that the G laser performs mode locking (10 MHz) and Q switching (500 Hz) to generate pulsed light of approximately 500 W. As shown in FIG. 3, the optical fiber of Example 1 was able to generate strong light even at long wavelengths of 1.24 rm or more, as shown in output light spectrum 4. On the other hand, the Raman light generated from the optical fiber of Comparative Example 1 has an output light spectrum 5 in FIG.
As shown in , it monotonically decreased on the longer wavelength side, and no strong light was obtained at wavelengths of 1.3 m or more. Example 2 Core is Si0278 mole%, P20515 mole%, Ce
An optical fiber was prepared in which the cladding had a composition of 027 mol %, Si 02 mol %, P 2055 mol %, and Ge 027 mol %.
この光フアィバはコア屈折率ｎ，＝１．４７７、クラツ
ド屈折率ｎ２；１．４７０、コア外径６仏ｍであり、１
．１仏ｍ以上で単一モード条件を満たしている。This optical fiber has a core refractive index n = 1.477, a cladding refractive index n2 = 1.470, a core outer diameter 6 fm, and a
．． The single mode condition is satisfied at 1 French m or more.
この光フアィバに前述したところと同様にＮｄ：ＹＡＧ
レーザーの光を入射したところ、実施例１に比べ、発生
した１．１２仏ｍおよび１．１８仏ｍの光強度は約１．
５倍になり、１．２４仏ｍ以上の長波長においても実施
例１より幾分強い光を発生させることができた。以上の
説明から明らかなように、本発明の光ファィバはＳｉ０
２−Ｐ夕５※ガラスより構成されるので、Ｓｉ０２ガラ
スをコアとする光フアィバに比べて同程度に光損失を低
くすることができ、しかもラマン散乱係数を大きくする
ことができるので、本発明光フアイバをファイバラマン
レーザ−用媒質として用いることにより従来の装置をそ
のまま用いて従来より広い波長域で、しかも従来より強
力なしーザー光を発生できるという利点を有する。This optical fiber is made of Nd:YAG as described above.
When laser light was incident, the light intensity of 1.12 m and 1.18 m was generated, compared to Example 1, and the light intensity was about 1.1 m.
5 times, and it was possible to generate light that was somewhat stronger than Example 1 even at long wavelengths of 1.24 m or more. As is clear from the above description, the optical fiber of the present invention has Si0
Since it is composed of 2-P glass, it can lower optical loss to the same extent as an optical fiber with a core of Si02 glass, and can also increase the Raman scattering coefficient, so the present invention By using an optical fiber as a medium for a fiber Raman laser, there is an advantage that laser light can be generated in a wider wavelength range than before and more powerful than before using conventional equipment as is.
また、コアおよびクラツドに、Ｓｉ０２とＰ２０５の他
にＷ０２を添加することによりレーザー光強度を大きく
することもできる。Furthermore, the laser light intensity can be increased by adding W02 in addition to Si02 and P205 to the core and cladding.
第１図はＳｉ０２−Ｑ０２系ガラスの組成とラマン散乱
強度の関係を表わす特性図、第２図はＳｉ０２一Ｐ２０
５系ガラスの組成とＰ２Ｑによるラマン散乱強度の関係
を表わす特性図、第３図は本発明光フアイバを用いたフ
ァイバラマンレーザーからの出射光スペクトル強度分布
を示す図、第４図は従来の光フアィバを用いたファイバ
ラマンレーザーからの出射光スペクトル強度分布を示す
図である。
１・・・・・・Ｓｉ０２のラマン散乱（４４０肌‐１）
強度、２・・・・・・Ｗ０２のラマン散乱（４２５弧‐
１）強度、３…・・・Ｐ２Ｑのラマン散乱（１３２０肌
‐１）強度、４・・・・・・実施例１の光フアィバを用
いた場合の出射光スペクトル、５・・・・・・比較例１
の光フアィバを用いた場合の出射光スペクトルｏ第３図
第１図
第２図
第４図Figure 1 is a characteristic diagram showing the relationship between the composition of Si02-Q02 glass and the Raman scattering intensity, and Figure 2 is a characteristic diagram showing the relationship between the composition of Si02-Q02 glass and the Raman scattering intensity.
A characteristic diagram showing the relationship between the composition of the 5-series glass and the Raman scattering intensity due to P2Q. Figure 3 is a diagram showing the spectral intensity distribution of the emitted light from a fiber Raman laser using the optical fiber of the present invention. Figure 4 is a diagram showing the spectral intensity distribution of the emitted light from a fiber Raman laser using the optical fiber of the present invention. FIG. 2 is a diagram showing the spectral intensity distribution of light emitted from a fiber Raman laser using a fiber. 1...Raman scattering of Si02 (440 skin-1)
Intensity, 2...Raman scattering of W02 (425 arc-
1) Intensity, 3... P2Q Raman scattering (1320 skin-1) intensity, 4... Emitted light spectrum when using the optical fiber of Example 1, 5... Comparative example 1
Output light spectrum when using an optical fiber of Fig. 3 Fig. 1 Fig. 2 Fig. 4
Claims (1)
いられる単一モード光フアイバにおいて、屈折率の高い
コアおよび該コアより屈折率の低いクラツドを実質的に
高純度のＳｉＯ＿２およびＰ＿２Ｏ＿５で形成し、かつ
前記コアのＰ＿２Ｏ＿５の含有量を１０モル％以上とし
たことを特徴とするフアイバラマンレーザー用光フアイ
バ。 ２ 特許請求の範囲第１項記載の光フアイバにおいて、
前記コアおよび前記クラツドは１〜２０モル％のＧｅＯ
＿２を含むことを特徴とするフアイバラマンレーザー用
光フアイバ。[Claims] 1. In a single mode optical fiber used as a laser medium for a fiber Brahman laser, a core with a high refractive index and a cladding with a lower refractive index than the core are formed of substantially high-purity SiO_2 and P_2O_5. An optical fiber for a fiber Brahman laser, characterized in that the content of P_2O_5 in the core is 10 mol% or more. 2. In the optical fiber according to claim 1,
The core and the cladding contain 1 to 20 mol% GeO.
An optical fiber for a fiber Brahman laser, characterized by containing _2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP54147030A JPS6035839B2 (en) | 1979-11-15 | 1979-11-15 | Optical fiber for fiber Brahman laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP54147030A JPS6035839B2 (en) | 1979-11-15 | 1979-11-15 | Optical fiber for fiber Brahman laser |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5670683A JPS5670683A (en) | 1981-06-12 |
| JPS6035839B2 true JPS6035839B2 (en) | 1985-08-16 |
Family
ID=15420941
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP54147030A Expired JPS6035839B2 (en) | 1979-11-15 | 1979-11-15 | Optical fiber for fiber Brahman laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6035839B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4790619A (en) * | 1986-04-25 | 1988-12-13 | American Telephone And Telegraph Company, At&T Bell Laboratories | Apparatus comprising Raman-active optical fiber |
| JP2692694B2 (en) * | 1987-05-25 | 1997-12-17 | 日本電信電話株式会社 | Optical fiber laser device |
| EP1174742B1 (en) * | 1995-07-28 | 2006-03-01 | Sabeus Photonics, Inc. | Method for changing the refractive index in germanium silicate glass |
| US5838700A (en) * | 1995-07-28 | 1998-11-17 | Nauchny Tsentr Volokonnoi Optiki Pri Institute Obschei Fiziki Rossiiskoi Akademii Nauk | Raman fibre laser, bragg fibre-optical grating and method for changing the refraction index in germanium silicate glass |
| GB9928474D0 (en) * | 1999-12-03 | 2000-02-02 | Secr Defence Brit | Laser effects and laser devices |
| JP4776085B2 (en) * | 2001-03-15 | 2011-09-21 | 古河電気工業株式会社 | Optical communication system using broadband Raman amplifier |
-
1979
- 1979-11-15 JP JP54147030A patent/JPS6035839B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5670683A (en) | 1981-06-12 |
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