JPH0364816B2 - - Google Patents
Info
- Publication number
- JPH0364816B2 JPH0364816B2 JP24078186A JP24078186A JPH0364816B2 JP H0364816 B2 JPH0364816 B2 JP H0364816B2 JP 24078186 A JP24078186 A JP 24078186A JP 24078186 A JP24078186 A JP 24078186A JP H0364816 B2 JPH0364816 B2 JP H0364816B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- preform
- refractive index
- lens
- order diffraction
- 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
- 238000000034 method Methods 0.000 claims description 5
- 238000010586 diagram Methods 0.000 description 10
- 238000005259 measurement Methods 0.000 description 10
- 239000000463 material Substances 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
- G01N21/412—Index profiling of optical fibres
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Light Guides In General And Applications Therefor (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
光フアイバやロツドレンズの製造方法として、
最終製品と同様な半径方向の屈折率分布を有する
プリフオームを作製し、これを細く引伸ばすこと
により製品を得る方法がある。[Detailed description of the invention] [Industrial application field] As a method for manufacturing optical fibers and rod lenses,
There is a method of obtaining a product by producing a preform having a radial refractive index distribution similar to that of the final product and stretching the preform thinly.
これらの製造に際して、プリフオームの屈折率
分布測定は、フアイバ化前のフイードバツクデー
タとして特に重要である。 In manufacturing these materials, measurement of the refractive index distribution of the preform is particularly important as feedback data before fiberization.
プリフオームの屈折率測定方法は、多種類ある
が、この発明は、その中の、非破壊で、精度の良
い屈折率分布測定方法に関するものである。 There are many methods for measuring the refractive index of a preform, and the present invention relates to a nondestructive and highly accurate refractive index distribution measuring method among them.
代表的な測定構成を第４図に示す。 A typical measurement configuration is shown in FIG.
He−Neレーザ１０の光線１２をミラー１４に
よつて任意の角度θ方向に曲げる。その光線１２
を第一のレンズ１６によつて光軸１１と平行な光
とし、マツチングオイル１８中のプリフオーム２
０に入射させる。 The beam 12 of the He--Ne laser 10 is bent by a mirror 14 at an arbitrary angle in the θ direction. The ray 12
is converted into light parallel to the optical axis 11 by the first lens 16, and the preform 2 in the matching oil 18
0.
入射光線は、プリフオーム２０の屈折率分布に
より、角度φ方向に曲がり、第２のレンズ２２と
シリンドリカルレンズ２４とを通り、観察面２５
にあるラインセンサ２６に入る。 The incident light beam is bent in the angle φ direction due to the refractive index distribution of the preform 20, passes through the second lens 22 and the cylindrical lens 24, and reaches the observation surface 25.
It enters the line sensor 26 located at.
２８はラインセンサ２６の電源ならびに位置検
出回路である。 28 is a power supply and position detection circuit for the line sensor 26.
以下の説明の都合上、ｘ，ｙの方向を矢印３０
のようにきめる。なお、ｙ方向は母材２０の軸と
同方向で、紙面に対して直角の方向であり、ｘ方
向は、ｙ方向と光軸１１の両方に対して直角な方
向である。 For convenience of explanation below, arrow 30 indicates the x and y directions.
Decide as follows. Note that the y direction is the same direction as the axis of the base material 20 and perpendicular to the paper surface, and the x direction is perpendicular to both the y direction and the optical axis 11.
出射角θは、次式から求められる。The output angle θ is obtained from the following equation.
φ＝tan-1（ｘ／ｆ） (1)
ｆ：第２のレンズ２２の焦点距離
ｘ：出射光のスポツト位置
この出射角φから、プリフオーム２０の屈折率
分布ｎ（ｒ）は、次式で求められる。 φ=tan -1 (x/f) (1) f: Focal length of the second lens 22 x: Spot position of the emitted light From this output angle φ, the refractive index distribution n(r) of the preform 20 can be calculated using the following formula. is required.
ｎ（ｒ）＝n2｛１−１／π∫a rφ（ｙ）
dy／（y2−r2）1/2 (2)
n2：マツチングオイル１８の屈折率
ａ：プリフオーム２０の半径
〔発明が解決しようとする問題点〕
プリフオーム２０への光線１２の入射位置を、
ｘ方向に順次ずらせてゆくと（ｙ方向の高さ一
定）、第５ａ図のように、出射光のレーザスポツ
ト３２は、観察面２５にあるライセンサ２６上
（ｘ軸方向上）を順次移動する。n(r)=n 2 {1-1/π∫ a r φ(y) dy/(y 2 −r 2 ) 1/2 (2) n 2 : Refractive index of matching oil 18 a : Refractive index of preform 20 Radius [Problem to be Solved by the Invention] When the incident position of the light ray 12 on the preform 20 is sequentially shifted in the x direction (the height in the y direction is constant), as shown in Fig. 5a, the laser of the emitted light The spot 32 sequentially moves on the licensor 26 on the observation surface 25 (in the x-axis direction).
その各位置のｘから、式(1)を用いて、φを求め、
それから(2)式により屈折率分布を得る。From x at each position, use equation (1) to find φ,
Then, the refractive index distribution is obtained using equation (2).
しかし、母材には作製時に形成される屈折率の
ゆらぎが存在する。 However, the base material has fluctuations in its refractive index that are formed during manufacturing.
そのため、レーザスポツトはただ一つだけ存在
するのではなく、第５ｂ図のように、０次回析光
３３の他に高次回析光３４が付随して存在する
（０次回析光３３だけが母材の軸と直角な平面内
に出射する）。 Therefore, there is not only one laser spot, but as shown in Fig. 5b, in addition to the 0th-order diffraction light 33, the higher-order diffraction light 34 also exists (only the 0th-order diffraction light 33 is the main beam). emitted in a plane perpendicular to the axis of the material).
ところが従来は、これら複数の回析光を、シリ
ンドリカルレンズ２４を使つて強制的にｘ軸上に
圧縮して、第５ａ図のレーザスポツト３２として
いた。 However, in the past, these plural diffraction lights were forcibly compressed on the x-axis using the cylindrical lens 24 to form the laser spot 32 shown in FIG. 5a.
したがつて、正確な情報が得られなかつた。 Therefore, accurate information could not be obtained.
この発明は、第１ａ図、第１ｂ図のように、
(1) シリンドリカルレンズ２４を使用して光線１
２の複数個の回析光スポツトを圧縮するという
ことはしないので、その代りに観察面２５に
TVカメラ３８のような２次元の受光素子を置
き、
(2) 出射光を２次元的に解析して、当該出射光の
中の０次回析光の出射角だけを測定すること、
によつて、上記問題の解決を図つたものである。
This invention, as shown in FIGS. 1a and 1b, (1) uses a cylindrical lens 24 to
Since the multiple diffraction light spots in step 2 are not compressed, instead, they are
By placing a two-dimensional light receiving element such as the TV camera 38, (2) analyzing the emitted light two-dimensionally and measuring only the emission angle of the zero-order diffraction light in the emitted light. , which aims to solve the above problem.
第1a図は本発明の実施例の測定構成をｙ方向
から見た説明図であり、第１ｂ図は同じくｘ方向
から見た状態の説明図である。
FIG. 1a is an explanatory diagram of a measurement configuration according to an embodiment of the present invention viewed from the y direction, and FIG. 1b is an explanatory diagram of the same as viewed from the x direction.
これらの図において、１０はHe−Neレーザ、
１６は第一のレンズ。 In these figures, 10 is a He-Ne laser,
16 is the first lens.
１８はマツチングオイル、２０はプリフオー
ム、１９はそれらが入つている容器で、２１はプ
リフオーム２０の中心面。 18 is matting oil, 20 is a preform, 19 is a container containing these, and 21 is the center surface of the preform 20.
容器１９全体を、ステツピングモータ３６によ
り、ｘ，ｙ両方向に移動できるようにする。 The entire container 19 can be moved in both x and y directions by a stepping motor 36.
２２は第２のレンズ。３８はTVカメラある
（外にCCD、半導体位置検出器などの２次元の受
光素子も使用できる）。 22 is the second lens. 38 has a TV camera (two-dimensional light-receiving elements such as CCD and semiconductor position detectors can also be used).
４０は信号処理回路、４２は出力である。 40 is a signal processing circuit, and 42 is an output.
(1) He−Neレーザ１０の光線１２を第一のレン
ズ１６で集光する。その光線をプリフオーム２
０の入つている容器１９に対して垂直に入射
し、光線１２の最小スポツトサイズがプリフオ
ーム２０の中心面２１に合うように、第一のレ
ンズ１６を調節する。
(1) The light beam 12 of the He-Ne laser 10 is focused by the first lens 16. Preform that ray 2
The first lens 16 is adjusted so that the minimum spot size of the light ray 12 is incident perpendicularly to the container 19 containing the light beam 12 and aligned with the central plane 21 of the preform 20.
(2) そして、プリフオーム２０の任意の位置に光
線１２をあてるために、ステツピングモータ３
６で容器１９全体をｘ方向に移動する。(2) Then, in order to apply the light beam 12 to an arbitrary position on the preform 20, the stepping motor 3 is
6, the entire container 19 is moved in the x direction.
(3) プリフオーム２０から出射した光を、第２の
レンズ２２を通してTVカメラ３８に入射させ
る。(3) The light emitted from the preform 20 is made to enter the TV camera 38 through the second lens 22.
上記のように、プリフオーム２０に屈折率の
ゆらぎが存在するとき、０次回析光３３だけ
が、母材の軸と直角な平面内に存在する。 As described above, when there is a fluctuation in the refractive index in the preform 20, only the zero-order diffracted light 33 exists in a plane perpendicular to the axis of the base material.
この場合は、上記のように、０次回析光３３
だけを取り出すようにするのであるから、入射
光線１２を含みプリフオーム軸と直角な面と
TVカメラ３８の光電面との交線上の光だけを
取り出せばよいように考えられるが、しかし、
測定系には多少の測定誤差、たとえばプリフオ
ームを置いたときの傾きなどが付随するので、
それを考慮して、上記の交線上だけでなく、そ
の近傍に存在する領域の光をも拾い出すように
する。 In this case, as mentioned above, the 0th order diffraction light 33
Since we are trying to extract only the incident ray 12, the plane that includes the incident ray 12 and is perpendicular to the preform axis.
It may be possible to extract only the light on the line of intersection with the photocathode of the TV camera 38, but,
The measurement system has some measurement errors, such as the inclination when placing the preform, so
Taking this into consideration, the system is designed to pick up not only the light on the above-mentioned intersection line but also the light in the area that exists in the vicinity.
(4) また、光ビームには広がりがあるので、実際
の解析は、画像の強度分布を２次元的にとらえ
て、その中心の位置を決定する。(4) Furthermore, since the light beam has a spread, the actual analysis involves capturing the intensity distribution of the image two-dimensionally and determining the position of its center.
(5) ０次回析光３３か高次回析光３４かの判別
は、次のように行う。(5) Discrimination between zero-order diffraction light 33 and higher-order diffraction light 34 is performed as follows.
すなわち、上記のように、０次回析光３３は
プリフオーム軸に直角な面内を動くのに対し
て、高次回析光３４はプリフオームの軸方向に
も位置を変化させる（第１ｂ図参照）。 That is, as described above, the zero-order diffraction light 33 moves in a plane perpendicular to the preform axis, whereas the higher-order diffraction light 34 also changes its position in the axial direction of the preform (see FIG. 1b).
そこで、プリフオーム２０への光線１２の入
射位置を微少量（プリフオーム外径の１〜数％
程度）変えてみる。すると、０次回析光３３の
中心位置だけが直線的に移動し、高次回析光３
４は円弧を画いて移動するので、区別がつく。 Therefore, the incident position of the light beam 12 on the preform 20 is adjusted by a very small amount (1 to several % of the preform outer diameter).
degree) Try changing it. Then, only the center position of the zero-order diffraction light 33 moves linearly, and the higher-order diffraction light 3
4 is easy to distinguish because it moves in an arc.
(6) このようにして、TVカメラ３８のような２
次元光センサの面における０次回析光３３の位
置が分かる。(6) In this way, two cameras like TV camera 38
The position of the zero-order diffracted light 33 on the surface of the dimensional optical sensor is known.
容器１９をｘ方向のみ移動させたとき、０次回
析光３３の像は、第２図のようになる。 When the container 19 is moved only in the x direction, the image of the 0th order diffraction light 33 becomes as shown in FIG.
各位置の０次回析光３３のｘの値から上記(1)式
により、φxが求められ、それから屈折率分布が
計算される。 From the x value of the zero-order diffracted light 33 at each position, φ x is determined by the above equation (1), and the refractive index distribution is calculated from it.
そ一例を第３図に示す。 An example is shown in Figure 3.
出射光を２次元的に解析して、当該出射光の中
の０次回析光の出射角だけを測定するので、
従来のようにシリンドリカルレンズを使用して全
ての回析光をモニタいたのと異なり、高次回析光
による測定誤差がなくなつて、全体の測定精度が
向上する。
Since the emitted light is analyzed two-dimensionally and only the emission angle of the 0th order diffracted light in the emitted light is measured, it is different from the conventional method of monitoring all diffracted light using a cylindrical lens. On the other hand, measurement errors due to higher-order diffraction light are eliminated, improving overall measurement accuracy.
第１ａ図は本発明の実施例の測定構成をｙ方向
から見た状態の説明図、第１ｂ図は本発明の実施
例の測定構成をｘ方向から見た状態の説明図、第
２図はTVカメラ３８で検出するレーザスポツト
３２の像の説明図、第３図はプリフオーム２０の
半径方向のゆらぎによる屈折率分布図、第４図は
従来の測定方法の説明図、第５ａ図はラインセン
サ２６により検出されるレーザスポツト３２の状
態の説明図、第５ｂ図シリンドリカルレンズ２４
を用いなかつた場合のレーザスポツトの説明図。
１０…He−Neレーザ、１１…光軸、１２…光
線、１４…ミラー、１６…第一のレンズ、１８…
マツチングオイル、１９…容器、２０…プリフオ
ーム、２１…中心面、２２…第２のレンズ、２４
…シリンドリカルレンズ、２５…観察面、２６…
ラインセンサ、３０…矢印、３１…矢印、３２…
レーザスポツト、３３…０次回析光スポツト、３
４…高次回析光スポツト、３６…ステツピングモ
ータ、３８…TVカメラ、４０…信号処理回路、
４２…出力。
Figure 1a is an explanatory diagram of the measurement configuration of the embodiment of the present invention viewed from the y direction, Figure 1b is an explanatory diagram of the measurement configuration of the embodiment of the invention viewed from the x direction, and Figure 2 is an explanatory diagram of the measurement configuration of the embodiment of the present invention viewed from the x direction. An explanatory diagram of the image of the laser spot 32 detected by the TV camera 38, Fig. 3 is a refractive index distribution diagram due to radial fluctuation of the preform 20, Fig. 4 is an explanatory diagram of the conventional measurement method, and Fig. 5a is a line sensor An explanatory diagram of the state of the laser spot 32 detected by the cylindrical lens 26, FIG. 5b
An explanatory diagram of a laser spot when the laser spot is not used. DESCRIPTION OF SYMBOLS 10... He-Ne laser, 11... Optical axis, 12... Ray, 14... Mirror, 16... First lens, 18...
Matching oil, 19... Container, 20... Preform, 21... Center plane, 22... Second lens, 24
...Cylindrical lens, 25...Observation surface, 26...
Line sensor, 30...arrow, 31...arrow, 32...
Laser spot, 33...0th order analysis light spot, 3
4...High-order analysis light spot, 36...Stepping motor, 38...TV camera, 40...Signal processing circuit,
42...Output.
Claims (1)
し、その出射光の出射角を測定することにより、
プリフオーム内の屈折率分布を決定する方法にお
いて、前記出射光を２次元的に解析して、当該出
射光の中の０次回析光の出射角だけを測定するこ
とを特徴とする、屈折率分布の測定方法。1. By emitting a light beam from the direction perpendicular to the axis of the preform and measuring the exit angle of the emitted light,
A method for determining a refractive index distribution within a preform, characterized in that the emitted light is analyzed two-dimensionally and only the emission angle of the zero-order diffracted light in the emitted light is measured. How to measure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24078186A JPS6395336A (en) | 1986-10-10 | 1986-10-10 | Measurement of refractive index distribution |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24078186A JPS6395336A (en) | 1986-10-10 | 1986-10-10 | Measurement of refractive index distribution |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6395336A JPS6395336A (en) | 1988-04-26 |
| JPH0364816B2 true JPH0364816B2 (en) | 1991-10-08 |
Family
ID=17064608
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24078186A Granted JPS6395336A (en) | 1986-10-10 | 1986-10-10 | Measurement of refractive index distribution |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6395336A (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5365329A (en) * | 1988-11-15 | 1994-11-15 | York Technology Limited | Apparatus and method for measuring refractive index |
| GB8826643D0 (en) * | 1988-11-15 | 1988-12-21 | York Technology Ltd | Measurement of refractive index |
| US5078488A (en) * | 1989-04-17 | 1992-01-07 | Rikagaku Kenkyusho | Method and apparatus for determining refractive index distribution |
| JP2661001B2 (en) * | 1989-04-17 | 1997-10-08 | 理化学研究所 | Method and apparatus for measuring refractive index distribution |
| JPH07109381B2 (en) * | 1989-04-17 | 1995-11-22 | 理化学研究所 | Refractive index distribution measuring device |
| JPH0812130B2 (en) * | 1989-05-24 | 1996-02-07 | 信越化学工業株式会社 | Method and apparatus for measuring refractive index distribution |
| JPH07117476B2 (en) * | 1989-05-24 | 1995-12-18 | 信越化学工業株式会社 | Refractive index distribution measuring method and measuring apparatus |
| JP3735063B2 (en) * | 2001-12-13 | 2006-01-11 | 古河電気工業株式会社 | Optical fiber preform refractive index measurement method |
| KR20030097242A (en) * | 2002-06-20 | 2003-12-31 | 학교법인 한양학원 | device for measuring the gain coefficient for photo-refractive materials |
| CN102494639B (en) * | 2011-10-18 | 2013-11-13 | 北京理工大学 | Laser divergence angle measuring device and measuring method based on full-automatic hole alignment method |
-
1986
- 1986-10-10 JP JP24078186A patent/JPS6395336A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6395336A (en) | 1988-04-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3922093A (en) | Device for measuring the roughness of a surface | |
| US4859861A (en) | Measuring curvature of transparent or translucent material | |
| JP2954708B2 (en) | Multifocal imaging system | |
| JPH0364816B2 (en) | ||
| JPH05332733A (en) | Detection optical system and method for detecting three-dimensional form | |
| CN110836642A (en) | Color triangular displacement sensor based on triangulation method and measuring method thereof | |
| JPH0648229B2 (en) | Refractive index measuring device | |
| JP3726028B2 (en) | 3D shape measuring device | |
| US4279513A (en) | Optical inspection system for large parts and for multiple measurements | |
| JPH06509416A (en) | Probe for surface measurement | |
| JP2004000004U6 (en) | Probe for surface measurement | |
| US3619067A (en) | Method and apparatus for determining optical focal distance | |
| CN1204047A (en) | Light beam direction micro drift detection system | |
| JP3162364B2 (en) | Optical sensor device | |
| JP3200927B2 (en) | Method and apparatus for measuring coating state | |
| JP2000509825A (en) | Optical scanning device | |
| JP2519775B2 (en) | Refraction angle measuring device | |
| JPH07209169A (en) | Method and device for measuring spatial distribution of concentration and grain size of floating particle group | |
| JP2661001B2 (en) | Method and apparatus for measuring refractive index distribution | |
| JPS63138204A (en) | Shape measuring method | |
| JP2577008B2 (en) | Refraction angle measuring device | |
| JPH07117476B2 (en) | Refractive index distribution measuring method and measuring apparatus | |
| JPS61151407A (en) | Non-contacting diameter gauge | |
| RU2055311C1 (en) | Method and device for measurement of torsion angle of distant object | |
| JPH0339709Y2 (en) |