JPH08201221A - Refractive index distribution measuring method and measuring apparatus - Google Patents
Refractive index distribution measuring method and measuring apparatusInfo
- Publication number
- JPH08201221A JPH08201221A JP4708094A JP4708094A JPH08201221A JP H08201221 A JPH08201221 A JP H08201221A JP 4708094 A JP4708094 A JP 4708094A JP 4708094 A JP4708094 A JP 4708094A JP H08201221 A JPH08201221 A JP H08201221A
- Authority
- JP
- Japan
- Prior art keywords
- refractive index
- optical fiber
- index distribution
- light
- fiber preform
- 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.)
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- Testing Of Optical Devices Or Fibers (AREA)
Abstract
(57)【要約】
【目的】光ファイバ母材の脈理や微細構造の大きさに合
わせてレーザ光の径を容易に変えることができ、測定精
度の高い屈折率分布の測定方法および測定装置を提供す
る。
【構成】屈折率分布の測定方法は、光ファイバ母材７の
軸方向とは垂直な方向から光１４を入射させ、その出射
光１７の光パターンを観察して光ファイバ母材７の屈折
率分布を測定する屈折率分布の測定方法において、入射
光１４の光路中で入射光１４の径を断続的に変化させ最
適な径を選択して測定する。屈折率分布の測定装置は、
光源１からの光１４が空間フィルタ３を通って光ファイ
バ母材７の軸方向とは垂直な方向から入射する入射光学
系と、該入射光学系から入射して光ファイバ母材７を通
った出射光１７の投影像を検出する撮像手段１２とを有
する屈折率分布の測定装置において、空間フィルタ３が
複数の径のアパーチャーを有し、その複数の径のアパー
チャーを切換えて入射光学系の光路が形成される。
(57) [Abstract] [Purpose] Measuring method and measuring device of refractive index distribution with high measurement accuracy because the diameter of laser light can be easily changed according to the striae of the optical fiber base material and the size of the microstructure. I will provide a. [Structure] The refractive index distribution is measured by injecting light 14 from a direction perpendicular to the axial direction of the optical fiber preform 7 and observing the optical pattern of the emitted light 17 to observe the refractive index of the optical fiber preform 7. In the method of measuring the refractive index distribution for measuring the distribution, the diameter of the incident light 14 is intermittently changed in the optical path of the incident light 14, and the optimum diameter is selected and measured. The refractive index distribution measuring device is
The light 14 from the light source 1 passes through the spatial filter 3 and is incident from a direction perpendicular to the axial direction of the optical fiber preform 7, and the incident optical system enters the optical fiber preform 7 and passes through the optical fiber preform 7. In a refractive index distribution measuring device having an image pickup means 12 for detecting a projected image of outgoing light 17, the spatial filter 3 has apertures of a plurality of diameters, and the apertures of the plurality of diameters are switched to change the optical path of the incident optical system. Is formed.
Description
【０００１】[0001]
【産業上の利用分野】本発明は、光ファイバ母材の屈折
率分布の測定方法および測定装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring method and a measuring device for a refractive index distribution of an optical fiber preform.
【０００２】[0002]
【従来の技術】光ファイバは光ファイバ母材を線引きし
て形成される。光ファイバ母材はＶＡＤ法等によって製
造される。光ファイバ母材は半径方向の屈折率がほぼ２
乗分布、軸方向の屈折率は均一になっている。良質な光
ファイバを得るためには線引きする前の光ファイバ母材
の屈折率分布を正確に測定することが必要である。2. Description of the Related Art An optical fiber is formed by drawing an optical fiber preform. The optical fiber preform is manufactured by the VAD method or the like. The optical fiber preform has a refractive index of approximately 2 in the radial direction.
The power distribution and the refractive index in the axial direction are uniform. In order to obtain a good quality optical fiber, it is necessary to accurately measure the refractive index distribution of the optical fiber preform before being drawn.
【０００３】光ファイバ母材は、製造される際に微細構
造を生じる。光ファイバ母材の屈折率分布を測定する際
に、微細構造を測定するため入射光は微細構造より小さ
くする必要がある。このため、図７に示すようにレーザ
光３０を絞る場合には、レーザ光３０の最小の径（ビー
ムウエスト径：２Ｗ0 ）と波長λおよび入射角θとの間
にＷ0 ＝λ／（π・θ）の関係があり、ビームウエスト
径２Ｗ0 を小さくするためにはレーザ光３０の径２Ｗを
大きくして入射角θを大きくしなければならない。Optical fiber preforms produce microstructures when manufactured. When measuring the refractive index distribution of the optical fiber preform, the incident light needs to be smaller than the fine structure in order to measure the fine structure. Therefore, when the laser light 30 is narrowed down as shown in FIG. 7, W 0 = λ / () between the minimum diameter (beam waist diameter: 2W 0 ) of the laser light 30 and the wavelength λ and the incident angle θ. π · θ), and in order to reduce the beam waist diameter 2W 0 , it is necessary to increase the diameter 2W of the laser beam 30 and increase the incident angle θ.
【０００４】また脈理を有する光ファイバ母材の屈折率
分布の測定方法として、レーザ光３０を光ファイバ母材
に入射させ、図８に示すように光ファイバ母材から出射
されスクリーン１９に投影された出射光の０次の回折光
スポット２１、１次の回折光スポット２２、２次の回折
光スポット２３のデータを２値化して最小２乗法により
直線近似を行ない、近似直線２０を求める。その後、光
ファイバ母材が装着されていない状態の出射光の投影像
を基準点０として、光ファイバ母材の中心軸と垂直にレ
ーザ光３０が通る平面、すなわちｙ軸との交点ｙc を求
めその交点ｙcの座標軸から出射角φを算出する。光フ
ァイバ母材の半径方向の各位置で出射角φを算出して、
この出射角φから光ファイバ母材の屈折率分布ｎ（ｒ）
を次式As a method of measuring the refractive index distribution of the optical fiber preform having striae, a laser beam 30 is made incident on the optical fiber preform and emitted from the optical fiber preform and projected on a screen 19 as shown in FIG. Data of the 0th-order diffracted light spot 21 of the emitted light, the 1st-order diffracted light spot 22 and the 2nd-order diffracted light spot 23 are binarized and linear approximation is performed by the least square method to obtain an approximate straight line 20. After that, with the projected image of the emitted light in a state in which the optical fiber preform is not mounted as the reference point 0, the intersection point y c with the plane through which the laser light 30 passes perpendicularly to the central axis of the optical fiber preform, that is, the y-axis. Then, the emission angle φ is calculated from the coordinate axis of the intersection point y c . Calculate the emission angle φ at each position in the radial direction of the optical fiber preform,
From this emission angle φ, the refractive index distribution n (r) of the optical fiber preform
Is
【０００５】[0005]
【数１】 [Equation 1]
【０００６】（ｎ2 はクラッドの屈折率、ａは光ファイ
バ母材の半径、ｒは入射位置）で算出する方法がある。
この方法においては、入射角θが大きい場合はスクリー
ン１９上の投影像２１〜２３が大きくなるため近似直線
２０の測定誤差が大きくなってしまい、測定精度を良く
するためにはレーザ光３０の径２Ｗを小さくして入射角
θを小さくしなければならない。(N 2 is the refractive index of the cladding, a is the radius of the optical fiber preform, and r is the incident position).
In this method, when the incident angle θ is large, the projected images 21 to 23 on the screen 19 are large, so that the measurement error of the approximate straight line 20 becomes large, and in order to improve the measurement accuracy, the diameter of the laser beam 30 is increased. The incident angle θ must be reduced by reducing 2W.
【０００７】このようにレーザ光の径には光ファイバ母
材の脈理や微細構造の大きさに合った最適な値がある
が、径を変えて屈折率分布を測定することができる方法
および装置はなかった。As described above, the diameter of the laser beam has an optimum value according to the striae of the optical fiber preform and the size of the fine structure, but a method capable of measuring the refractive index distribution by changing the diameter and There was no device.
【０００８】[0008]
【発明が解決しようとする課題】本発明は前記の課題を
解決するためなされたもので、光ファイバ母材の脈理や
微細構造の大きさに合わせてレーザ光の径を容易に変え
ることができ、測定精度の高い屈折率分布の測定方法お
よび測定装置を提供することを目的とする。SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the diameter of laser light can be easily changed according to the striae of the optical fiber preform and the size of the fine structure. An object of the present invention is to provide a method and a device for measuring a refractive index distribution that can be measured with high accuracy.
【０００９】[0009]
【課題を解決するための手段】前記の目的を達成するた
めになされた本発明の屈折率分布の測定方法は、図１に
示すように光ファイバ母材７の軸方向とは垂直な方向か
ら光１４を入射させ、その出射光１７の光パターンを観
察して光ファイバ母材７の屈折率分布を測定する屈折率
分布の測定方法において、入射光１４の光路中で入射光
１４の径を断続的に変化させ最適な径を選択して測定す
る。The method for measuring the refractive index distribution of the present invention, which was carried out to achieve the above-mentioned object, is performed from a direction perpendicular to the axial direction of the optical fiber preform 7 as shown in FIG. In the method of measuring the refractive index distribution in which the light 14 is made incident and the optical pattern of the emitted light 17 is observed to measure the refractive index distribution of the optical fiber preform 7, the diameter of the incident light 14 is adjusted in the optical path of the incident light 14. Measure by selecting the optimum diameter by changing it intermittently.
【００１０】前記の目的を達成するためになされた本発
明の屈折率分布の測定装置は、図１に示すように光源１
からの光１４が空間フィルタ３を通って光ファイバ母材
７の軸方向とは垂直な方向から入射する入射光学系と、
該入射光学系から入射して光ファイバ母材７を通った出
射光１７の投影像を検出する撮像手段１２とを有する屈
折率分布の測定装置において、空間フィルタ３が複数の
径のアパーチャー１８（図２参照）を有し、その複数の
径のアパーチャー１８を切換えて入射光学系の光路が形
成される。The refractive index profile measuring apparatus of the present invention, which has been made to achieve the above-mentioned object, comprises a light source 1 as shown in FIG.
An incident optical system in which the light 14 from is incident from a direction perpendicular to the axial direction of the optical fiber preform 7 through the spatial filter 3;
In the refractive index distribution measuring device having an image pickup means 12 for detecting a projected image of the outgoing light 17 which has entered from the incident optical system and has passed through the optical fiber preform 7, the spatial filter 3 has an aperture 18 of a plurality of diameters ( (See FIG. 2), the apertures 18 having a plurality of diameters are switched to form the optical path of the incident optical system.
【００１１】[0011]
【作用】本発明の屈折率分布の測定方法および測定装置
は、図１に示すように入射光路中に複数の径のアパーチ
ャー１８を有する回転可能な空間フィルタ３を入れるこ
とにより、入射光１４の入射角を任意に変えることがで
き、ビームウエスト径２Ｗ0 を最適の径にして測定する
ことができる。このため出射光１７をスクリーン１１上
に投影させてその投影像のデータを演算処理して近似直
線を求める際、誤差のない近似直線を求めることができ
る。In the method and apparatus for measuring the refractive index distribution of the present invention, as shown in FIG. 1, the rotatable spatial filter 3 having the apertures 18 having a plurality of diameters is inserted in the incident light path so that the incident light 14 can be detected. The angle of incidence can be changed arbitrarily, and the beam waist diameter 2W 0 can be set to an optimum diameter for measurement. Therefore, when the outgoing light 17 is projected on the screen 11 and the data of the projected image is arithmetically processed to obtain an approximate straight line, an approximate straight line having no error can be obtained.
【００１２】[0012]
【実施例】以下、本発明の実施例を詳細に説明する。EXAMPLES Examples of the present invention will be described in detail below.
【００１３】図１は本発明の屈折率分布の測定装置の概
略構成図である。Ｈｅ−Ｎｅレーザ１から出射したレー
ザ光１４が通る位置にビームエクスパンダ２、空間フィ
ルタ３、集光用レンズ６がこの順に配置されている。FIG. 1 is a schematic configuration diagram of a refractive index distribution measuring apparatus of the present invention. The beam expander 2, the spatial filter 3, and the condenser lens 6 are arranged in this order at a position where the laser light 14 emitted from the He-Ne laser 1 passes.
【００１４】空間フィルタ３は、図２に示すように、円
板状の遮光板３に異なる大きさの複数のアパーチャー１
８が明けられている。遮光板３の中心がパルスモータ４
の回転軸に連結されている。複数のアパーチャー１８の
中心は、パルスモータ４の回転軸（すなわち遮光板３の
中心）を中心とする円上に並べられている。As shown in FIG. 2, the spatial filter 3 includes a disc-shaped light shielding plate 3 and a plurality of apertures 1 of different sizes.
8 is open. The center of the shading plate 3 is the pulse motor 4
Is connected to the rotating shaft of. The centers of the plurality of apertures 18 are arranged on a circle centered on the rotation axis of the pulse motor 4 (that is, the center of the light shielding plate 3).
【００１５】集光用レンズ６を通ったレーザ光１４が最
小の径になる位置に、セル８に貫通して固定された光フ
ァイバ母材７が配置されており、セル８はマッチングオ
イル９で満たされている。光ファイバ母材７を通った出
射光１７の投影像が写し出される位置にスクリーン１
１、投影像を撮像できる位置にカメラ１２が配置されて
いる。カメラ１２にはコンピュータ１３が接続されてい
る。An optical fiber preform 7 fixed through the cell 8 is arranged at a position where the laser beam 14 having passed through the condenser lens 6 has a minimum diameter. The cell 8 is made of a matching oil 9. be satisfied. The screen 1 is placed at a position where a projected image of the outgoing light 17 passing through the optical fiber base material 7 is projected.
1. The camera 12 is arranged at a position where a projected image can be captured. A computer 13 is connected to the camera 12.
【００１６】Ｈｅ−Ｎｅレーザ１から出射したレーザ光
１４はビームエクスパンダ２でその径が広げられ、必要
に応じてパルスモータ４を動作させて空間フィルタ３を
回転させアパーチャー１８を通って最適な径にされる。
空間フィルタ３を通過したレーザ光１４は集光用レンズ
６により収斂され光ファイバ母材７の中心で最小の径と
なる。光ファイバ母材７を通過した出射光１７はスクリ
ーン１１にその投影像が写し出される。写し出された投
影像はカメラ１２で撮像され、カメラ１２で得られた投
影像の位置からコンピュータ１３によって出射角が算出
されて屈折率分布が求められる。The laser beam 14 emitted from the He-Ne laser 1 is expanded in diameter by the beam expander 2, and the pulse motor 4 is operated as necessary to rotate the spatial filter 3 and pass through the aperture 18 to make it optimal. Made to diameter.
The laser beam 14 that has passed through the spatial filter 3 is converged by the condenser lens 6 and has the smallest diameter at the center of the optical fiber preform 7. A projected image of the emitted light 17 that has passed through the optical fiber preform 7 is projected on the screen 11. The projected image is projected by the camera 12, and the exit angle is calculated by the computer 13 from the position of the projected image obtained by the camera 12 to obtain the refractive index distribution.
【００１７】上記の装置、動作により以下の条件で測定
を行なった。Measurement was carried out under the following conditions by the above-mentioned device and operation.
【００１８】光ファイバ母材７をその中心と集光用レン
ズ６との距離が３００ｍｍになるように配置して、Ｈｅ
−Ｎｅレーザ１からのレーザ光１４の径をビームエクス
パンダ２で１５ｍｍに広げ、径１〜１５ｍｍのアパーチ
ャー１８が明けられた空間フィルタ３の径４ｍｍのアパ
ーチャー１８を用いて屈折率分布を測定した。また光フ
ァイバ母材のコアの最大屈折率をｎ1 、クラッドの屈折
率をｎ2 として屈折率を測定し、次式で示す比屈折率差
Δ Δ＝（ｎ1 −ｎ2 ）×１００／ｎ1 を求め、この比屈折率差Δの標準偏差σを算出して比屈
折率差Δで正規化し、（σ／Δ）で示される繰り返し精
度を調べた。The optical fiber preform 7 is arranged so that the distance between its center and the condenser lens 6 is 300 mm, and He
-The diameter of the laser beam 14 from the Ne laser 1 was expanded to 15 mm by the beam expander 2, and the refractive index distribution was measured using the aperture 18 of 4 mm in diameter of the spatial filter 3 in which the aperture 18 of 1 to 15 mm in diameter was opened. . The refractive index was measured with the maximum refractive index of the core of the optical fiber preform being n 1 and the refractive index of the cladding being n 2 , and the relative refractive index difference ΔΔ = (n 1 −n 2 ) × 100 / n 1 was calculated, the standard deviation σ of this relative refractive index difference Δ was calculated, normalized by the relative refractive index difference Δ, and the repeatability represented by (σ / Δ) was examined.
【００１９】まず光ファイバ母材７として脈理を有する
母材を用いて測定すると、図３に示すように屈折率分布
に誤差はなく繰り返し精度は０．００３と良かった。次
にコアの近傍に屈折率の高い微細構造を有する母材を用
いて測定すると、図４に示すように微細構造を測定する
ことができなかった。そこで空間フィルタ３を回転させ
径１５ｍｍのアパーチャー１８にしたところ微細構造を
測定することができ、繰り返し精度も０．００１と良か
った。First, when a preform having striae was used as the optical fiber preform 7, the refractive index distribution had no error as shown in FIG. 3 and the repeatability was good at 0.003. Next, when measurement was performed using a base material having a fine structure with a high refractive index in the vicinity of the core, the fine structure could not be measured as shown in FIG. Therefore, when the spatial filter 3 was rotated to form the aperture 18 having a diameter of 15 mm, the fine structure could be measured, and the repeatability was as good as 0.001.
【００２０】比較のため、光ファイバ母材７をその中心
と集光用レンズ６との距離が３００ｍｍになるように配
置して、Ｈｅ−Ｎｅレーザ１からのレーザ光１４の径を
ビームエクスパンダ２で１５ｍｍに広げ空間フィルタ３
を使用せずに屈折率分布を測定した。まず光ファイバ母
材７として脈理を有する母材の屈折率分布を測定する
と、図５に示すように誤差を生じてしまい繰り返し精度
も０．１と悪かった。次に微細構造を有する母材の屈折
率分布を測定すると、図６に示すように微細構造を測定
することができたが、繰り返し精度は０．００３と実施
例よりも悪かった。For comparison, the optical fiber preform 7 is arranged such that the distance between the center of the optical fiber preform 7 and the condenser lens 6 is 300 mm, and the diameter of the laser beam 14 from the He-Ne laser 1 is set to the beam expander. Spatial filter 3 by expanding to 15 mm by 2
Was used to measure the refractive index distribution. First, when the refractive index distribution of the optical fiber preform 7 having a striae was measured, an error occurred as shown in FIG. 5, and the repeatability was poor at 0.1. Next, when the refractive index distribution of the base material having a fine structure was measured, the fine structure could be measured as shown in FIG. 6, but the repeatability was 0.003, which was worse than that of the example.
【００２１】[0021]
【発明の効果】以上、詳細に説明したように本発明の測
定方法および測定装置により屈折率分布を測定すれば、
光ファイバ母材の脈理や微細構造の大きさに合わせてレ
ーザ光の径を容易に変えることができるため、繰り返し
精度が良く測定精度が高い。As described above in detail, when the refractive index distribution is measured by the measuring method and the measuring apparatus of the present invention,
Since the diameter of the laser light can be easily changed according to the striae of the optical fiber preform and the size of the fine structure, the repeatability is good and the measurement accuracy is high.
【図１】本発明を適用する屈折率分布の測定装置の概略
構成図である。FIG. 1 is a schematic configuration diagram of a refractive index distribution measuring apparatus to which the present invention is applied.
【図２】本発明を適用する屈折率分布の測定装置の一部
品の側面図および部分断面図である。FIG. 2 is a side view and a partial cross-sectional view of one component of a refractive index distribution measuring device to which the present invention is applied.
【図３】本発明を適用する屈折率分布の測定方法の実施
例における屈折率分布を示す図である。FIG. 3 is a diagram showing a refractive index distribution in an example of a refractive index distribution measuring method to which the present invention is applied.
【図４】本発明を適用する屈折率分布の測定方法の実施
例における屈折率分布を示す図である。FIG. 4 is a diagram showing a refractive index distribution in an example of a refractive index distribution measuring method to which the present invention is applied.
【図５】従来の屈折率分布の測定方法の例における屈折
率分布を示す図である。FIG. 5 is a diagram showing a refractive index distribution in an example of a conventional method of measuring a refractive index distribution.
【図６】従来の屈折率分布の測定方法の例における屈折
率分布を示す図である。FIG. 6 is a diagram showing a refractive index distribution in an example of a conventional method of measuring a refractive index distribution.
【図７】入射レーザ光のビームウエスト径と入射角との
関係を説明する図である。FIG. 7 is a diagram illustrating a relationship between a beam waist diameter of incident laser light and an incident angle.
【図８】出射光のスクリーン上の投影像および近似直線
を示す図である。FIG. 8 is a diagram showing a projected image of outgoing light on a screen and an approximate straight line.
１はＨｅ−Ｎｅレーザ、２はビームエクスパンダ、３は
空間フィルタ、４はパルスモータ、６は集光用レンズ、
７は光ファイバ母材、８はセル、９はマッチングオイ
ル、１１・１９はスクリーン、１２はカメラ、１３はコ
ンピュータ、１４は入射光、１７は出射光、１８はアパ
ーチャー、２０は近似直線、２１〜２３は投影像、３０
はレーザ光である。1 is a He-Ne laser, 2 is a beam expander, 3 is a spatial filter, 4 is a pulse motor, 6 is a condenser lens,
7 is an optical fiber base material, 8 is a cell, 9 is a matching oil, 11 and 19 are screens, 11 and 19 are screens, 12 is a camera, 13 is a computer, 14 is incident light, 17 is outgoing light, 18 is an aperture, 20 is an approximate straight line, 21 -23 is a projected image, 30
Is laser light.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 島田 忠克 群馬県安中市磯部２丁目13番１号 信越化 学工業株式会社精密機能材料研究所内 (72)発明者 大野田 忠与 東京都千代田区神田錦町二丁目９番地 信 越エンジニアリング株式会社内 (72)発明者 市川 和弘 東京都千代田区神田錦町二丁目９番地 信 越エンジニアリング株式会社内 (72)発明者 鈴木 敏之 東京都千代田区神田錦町二丁目９番地 信 越エンジニアリング株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadakatsu Shimada 2-13-1, Isobe, Annaka-shi, Gunma Shin-Etsu Kagaku Kogyo Co., Ltd., Institute for Precision Materials (72) Tadayo Onoda Chiyoda-ku, Tokyo 2-chome Kanda Nishikicho Shin-Etsu Engineering Co., Ltd. (72) Inventor Kazuhiro Ichikawa 2-chome Kanda Nishiki-cho Chiyoda-ku, Tokyo Shin-Etsu Engineering Co., Ltd. (72) Toshiyuki Suzuki 2-chome Kanda Nishiki-cho, Chiyoda-ku, Tokyo 9th Shin-Etsu Engineering Co., Ltd.
Claims (2)
から光を入射させ、その出射光の光パターンを観察して
光ファイバ母材の屈折率分布を測定する屈折率分布の測
定方法において、入射光の光路中で該入射光の径を断続
的に変化させ最適な径を選択して測定することを特徴と
する屈折率分布の測定方法。1. A method of measuring a refractive index distribution in which light is incident from a direction perpendicular to the axial direction of the optical fiber preform and the optical pattern of the emitted light is observed to measure the refractive index distribution of the optical fiber preform. 2. A method for measuring a refractive index distribution, characterized in that the diameter of the incident light is intermittently changed in the optical path of the incident light and an optimum diameter is selected and measured.
ファイバ母材の軸方向とは垂直な方向から入射する入射
光学系と、該入射光学系から入射して光ファイバ母材を
通った出射光の投影像を検出する撮像手段とを有する屈
折率分布の測定装置において、該空間フィルタが複数の
径のアパーチャーを有し、その複数の径のアパーチャー
を切換えて入射光学系の光路が形成されることを特徴と
する屈折率分布の測定装置。2. An incident optical system in which light from a light source passes through a spatial filter in a direction perpendicular to the axial direction of the optical fiber preform, and enters from the incident optical system and passes through the optical fiber preform. In a refractive index distribution measuring device having an imaging means for detecting a projected image of emitted light, the spatial filter has apertures of a plurality of diameters, and the apertures of the plurality of diameters are switched to form an optical path of an incident optical system. An apparatus for measuring a refractive index distribution, characterized in that
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|---|---|---|---|
| JP04708094A JP3470729B2 (en) | 1994-03-17 | 1994-03-17 | Method and apparatus for measuring refractive index distribution |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04708094A JP3470729B2 (en) | 1994-03-17 | 1994-03-17 | Method and apparatus for measuring refractive index distribution |
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| Publication Number | Publication Date |
|---|---|
| JPH08201221A true JPH08201221A (en) | 1996-08-09 |
| JP3470729B2 JP3470729B2 (en) | 2003-11-25 |
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| JP04708094A Expired - Lifetime JP3470729B2 (en) | 1994-03-17 | 1994-03-17 | Method and apparatus for measuring refractive index distribution |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0994341A1 (en) * | 1998-10-12 | 2000-04-19 | Issei Sasaki | Method of measuring distribution of internal refractive index for optical fibre preform and measuring device |
| EP4459264A1 (en) * | 2023-05-03 | 2024-11-06 | Heraeus Quartz North America LLC | Ultra low-na refractive index profiling system and method for filtering out severely disturbing diffraction effects |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105784336B (en) * | 2016-04-26 | 2018-05-18 | 哈尔滨工程大学 | A kind of transmission of optical fibre device and reflecting properties test device and method |
-
1994
- 1994-03-17 JP JP04708094A patent/JP3470729B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0994341A1 (en) * | 1998-10-12 | 2000-04-19 | Issei Sasaki | Method of measuring distribution of internal refractive index for optical fibre preform and measuring device |
| US6611321B1 (en) | 1998-10-12 | 2003-08-26 | Issei Sasaki | Method of measuring distribution of internal reactive index for optical fiber preform and measuring device |
| EP4459264A1 (en) * | 2023-05-03 | 2024-11-06 | Heraeus Quartz North America LLC | Ultra low-na refractive index profiling system and method for filtering out severely disturbing diffraction effects |
| US12560537B2 (en) | 2023-05-03 | 2026-02-24 | Heraeus Quartz North America Llc | Ultra low-na refractive index profiling system and method for filtering out severely disturbing diffraction effects |
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| JP3470729B2 (en) | 2003-11-25 |
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