JPH0933393A - Measuring device for optical waveguide type diffraction grating - Google Patents

Measuring device for optical waveguide type diffraction grating

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Publication number
JPH0933393A
JPH0933393A JP7182863A JP18286395A JPH0933393A JP H0933393 A JPH0933393 A JP H0933393A JP 7182863 A JP7182863 A JP 7182863A JP 18286395 A JP18286395 A JP 18286395A JP H0933393 A JPH0933393 A JP H0933393A
Authority
JP
Japan
Prior art keywords
optical waveguide
diffraction grating
light
type diffraction
waveguide type
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.)
Pending
Application number
JP7182863A
Other languages
Japanese (ja)
Inventor
Masaichi Mobara
政一 茂原
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Electric Industries Ltd
Original Assignee
Sumitomo Electric Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sumitomo Electric Industries Ltd filed Critical Sumitomo Electric Industries Ltd
Priority to JP7182863A priority Critical patent/JPH0933393A/en
Publication of JPH0933393A publication Critical patent/JPH0933393A/en
Pending legal-status Critical Current

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  • Light Guides In General And Applications Therefor (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Testing Of Optical Devices Or Fibers (AREA)

Abstract

PROBLEM TO BE SOLVED: To directly, quantitatively, and easily measure the form, structure and optical characteristic of an optical waveguide type diffraction grating. SOLUTION: The light from a light source is passed through the annular pupil 16a of a ring diaphragm 16, made into a parallel light (reference light) hυ by a condenser 18, and incident from one side surface of an optical waveguide type diffraction grating 30 sealed in a reflective index matching agent 28 at a proper angle. The reference light hυ is diffracted according to the refractive index distribution in the optical waveguide type diffraction grating 30, the diffracted light is transmitted by an objective lens 20, the 0-order diffracted light is phase-modulated when transmitted by an annular phase film 22a provided on a phase plate 22, while other high-order diffracted lights are transmitted by the part other than the phase film 22a, they are mutually interfered on the light receiving surface of a CCD solid image pickup device 24, and the image of the pattern of the interfered lights is two-dimensionally picked up. A microcomputer system 26 performs a signal processing for the video signal SV of the pattern, thereby extracting the characteristic of the optical waveguide type diffraction grating 30.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は、光導波路型回折格
子の屈折率分布等を測定する為の測定装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device for measuring the refractive index distribution of an optical waveguide type diffraction grating.

【０００２】[0002]

【従来の技術】光導波路型回折格子は、光を伝搬する光
導波路中のある領域に紫外線を照射等することにより、
その光導波路の元の屈折率とは異なる屈折率分布が形成
されて成る構造を有し、その屈折率分布に伴って所定の
波長選択性を発揮するものである。2. Description of the Related Art An optical waveguide type diffraction grating is produced by irradiating a certain region in an optical waveguide that propagates light with ultraviolet rays.
The optical waveguide has a structure in which a refractive index distribution different from the original refractive index of the optical waveguide is formed, and a predetermined wavelength selectivity is exhibited according to the refractive index distribution.

【０００３】例えば、光ファイバー等を用いた光導波路
型回折格子にあっては、光導波方向に沿った部分縦断面
図１０に示す如く、光導波路であるコアのある領域に、
その光導波方向（コアの長手方向）に沿って所定ピッチ
で複数個の屈折率変化部ＣＰ１，ＣＰ２，ＣＰ３，ＣＰ
４，ＣＰ５……が形成されている。したがって、この領
域には、屈折率変化部ＣＰ１，ＣＰ２，ＣＰ３，ＣＰ
４，ＣＰ５……と元々コアと同じ屈折率の部分ＣＮ１，
ＣＮ２，ＣＮ３，ＣＮ４……とが交互に配列されて成る
屈折率分布が形成されている。そして、屈折率分布のピ
ッチをΔ、コアの屈折率をｎとすると、λ＝２ｎΔで決
まる波長の光を選択的に反射する波長選択性が発揮さ
れ、かかる波長選択性を発揮させる領域を光導波路型回
折格子と呼ぶと共に、特に光ファイバを用いた図１０に
示す如き光導波路型回折格子をファイバグレーティング
と呼んでいる。For example, in an optical waveguide type diffraction grating using an optical fiber or the like, as shown in a partial longitudinal sectional view along the optical waveguide direction, as shown in FIG.
A plurality of refractive index changing parts CP1, CP2, CP3, CP at a predetermined pitch along the optical waveguide direction (longitudinal direction of the core).
4, CP5 ... are formed. Therefore, in this region, the refractive index changing portions CP1, CP2, CP3, CP
4, CP5 ... and the portion CN1, which originally has the same refractive index as the core
A refractive index distribution is formed by alternately arranging CN2, CN3, CN4 .... When the pitch of the refractive index distribution is Δ and the refractive index of the core is n, wavelength selectivity that selectively reflects light having a wavelength determined by λ = 2nΔ is exerted, and a region that exerts such wavelength selectivity is guided by light. In addition to being called a waveguide diffraction grating, an optical waveguide diffraction grating using an optical fiber as shown in FIG. 10 is called a fiber grating.

【０００４】また、かかる波長選択性を利用することに
より、様々な光学素子等としての応用が期待されてい
る。Further, by utilizing such wavelength selectivity, application as various optical elements and the like is expected.

【０００５】ところで、このような光導波路型回折格子
の特性や構造を測定することは、屈折率分布と実際の波
長選択性との関係を解析したり、所望の波長選択性の光
導波路型回折格子を製造する為の構造上の情報を入手し
たり、光導波路型回折格子の構造欠陥を直接的に観測す
る等、様々な点において有意義である。By measuring the characteristics and structure of such an optical waveguide type diffraction grating, the relationship between the refractive index distribution and the actual wavelength selectivity can be analyzed and the optical waveguide type diffraction grating with a desired wavelength selectivity can be analyzed. It is significant in various respects such as obtaining structural information for manufacturing a grating and directly observing a structural defect of an optical waveguide type diffraction grating.

【０００６】従来の測定技術にあっては、例えば図１０
に示すファイバグレーティングを測定する場合、光フィ
バのコアの一方から所定波長のレーザ光（参照光）を導
入し、それによって得られる反射光と出力光（透過光）
のスペクトラムを計測することによって、波長選択性の
良否や光透過率を調べていた。また、実際の構造を調べ
るためには、光導波路回折格子の一部分を削り取り、そ
れを光学顕微鏡で拡大して観測していた。In the conventional measuring technique, for example, FIG.
When measuring the fiber grating shown in, the laser light (reference light) of a predetermined wavelength is introduced from one of the cores of the optical fiber, and the reflected light and the output light (transmitted light) obtained by that are introduced.
The quality of wavelength selectivity and the light transmittance were investigated by measuring the spectrum of. Further, in order to investigate the actual structure, a part of the optical waveguide diffraction grating was shaved off, and it was observed by enlarging it with an optical microscope.

【０００７】[0007]

【発明が解決しようとする課題】しかしながら、従来の
測定技術にあっては、まず、参照光を導入したときの反
射光と出力光のスペクトラムを測定する場合には、光導
波路型回折格子全体としての（換言すれば、総合的な）
光学特性を調べることは可能であるが、屈折率分布の個
々の部分の形状や構造を詳細に調べて、これら個々の形
状等の違い起因する光学特性への影響を調べることは困
難であった。即ち、この従来の測定技術では、上記総合
的な光学特性から間接的に屈折率分布の個々部分の形状
等を推定するに止まり、直接的に形状等を観測すること
ができないために、測定精度の向上には自ずから限界が
あった。However, in the conventional measurement technique, first, when measuring the spectra of the reflected light and the output light when the reference light is introduced, the entire optical waveguide type diffraction grating is used. Of (in other words, comprehensive)
It is possible to examine the optical characteristics, but it was difficult to examine the shape and structure of each part of the refractive index distribution in detail, and to investigate the effect on the optical characteristics due to the difference in these individual shapes. . That is, in this conventional measurement technique, it is only possible to indirectly estimate the shape and the like of the individual portions of the refractive index distribution from the above comprehensive optical characteristics, and it is not possible to directly observe the shape and the like. There was a limit to the improvement of.

【０００８】また、光導波路回折格子の一部分を削り取
り、それを光学顕微鏡で拡大して観測する場合には、サ
ブミクロンオーダーで微細加工されている光導波路型回
折格子を高い精度で削り取ることが極めて困難であり、
したがって、光導波路回折格子の各部の形状や構造を高
精度で観察することができなかったり、測定作業が極め
て煩雑となる等の問題があった。Further, when a part of the optical waveguide diffraction grating is shaved off and observed with an optical microscope in an enlarged scale, it is extremely necessary to grind off the optical waveguide type diffraction grating finely processed in the submicron order with high accuracy. Difficult,
Therefore, there are problems that the shape and structure of each part of the optical waveguide diffraction grating cannot be observed with high accuracy, and the measurement work becomes extremely complicated.

【０００９】本発明は、このような従来の技術に鑑みて
成されたものであり、光導波路型回折格子の形状・構造
及び光学特性を直接的且つ定量的に、更に簡易に測定す
ることができる光導波路型回折格子の測定装置を提供す
ることを目的とする。The present invention has been made in view of such a conventional technique, and can directly and quantitatively and easily measure the shape / structure and optical characteristics of an optical waveguide type diffraction grating. It is an object of the present invention to provide an optical waveguide type diffraction grating measuring device that can be used.

【００１０】[0010]

【課題を解決するための手段】請求項１に係る発明にあ
っては、光導波方向に沿って屈折率の変化分布を有する
光導波路型回折格子を測定する光導波路型回折格子の測
定装置において、前記光導波方向に対して直交する方向
より前記光導波路型回折格子に参照光を照射する投光系
と、前記参照光が前記屈折率の変化分布に応じて屈折さ
れると共に透過又は反射してなる屈折光を任意の倍率で
拡大する光学系と、前記光学系を通過した前記屈折光の
投影パターンを受光する受光部とを具備する構成とし
た。According to a first aspect of the invention, there is provided an optical waveguide type diffraction grating measuring apparatus for measuring an optical waveguide type diffraction grating having a refractive index change distribution along an optical waveguide direction. A projection system that irradiates the optical waveguide type diffraction grating with reference light in a direction orthogonal to the optical waveguide direction, and the reference light is refracted according to the change distribution of the refractive index and is transmitted or reflected. The optical system configured to magnify the refracted light thus obtained at an arbitrary magnification, and the light receiving unit for receiving the projection pattern of the refracted light that has passed through the optical system are provided.

【００１１】これにより、受光部では、光導波路型回折
格子の屈折率分布に応じて屈折した屈折光の投影パター
ンを受光することにより、光導波路型回折格子の形状・
構造及び屈折率分布等の光学特性を直接的且つ定量的
に、更に簡易に測定することが可能となる。As a result, the light receiving section receives the projection pattern of the refracted light refracted according to the refractive index distribution of the optical waveguide type diffraction grating, and thereby the shape of the optical waveguide type diffraction grating is obtained.
It becomes possible to directly and quantitatively and easily measure the optical characteristics such as the structure and the refractive index distribution.

【００１２】請求項２に係る発明にあっては、光導波方
向に沿って屈折率の変化分布を有する光導波路型回折格
子を測定する光導波路型回折格子の測定装置において、
前記光導波方向に対して任意の傾斜角度の方向より前記
光導波路型回折格子に参照光を照射する投光系と、前記
参照光が前記光導波路型回折格子によって回折されると
共に透過又は反射してなる回折光を任意の倍率で拡大す
る光学系と、前記光学系中に設けられ、前記回折光のう
ち所定次数の回折光を位相変調する位相板と、前記光学
系を通過した前記回折光による干渉光の投影パターンを
受光する受光部とを具備する構成とした。According to a second aspect of the present invention, there is provided an optical waveguide type diffraction grating measuring apparatus for measuring an optical waveguide type diffraction grating having a refractive index change distribution along an optical waveguide direction.
A light projecting system that irradiates the optical waveguide type diffraction grating with reference light from a direction having an arbitrary inclination angle with respect to the optical waveguide direction, and the reference light is diffracted by the optical waveguide type diffraction grating and transmitted or reflected. An optical system that magnifies the diffracted light at an arbitrary magnification, a phase plate that is provided in the optical system, and that modulates the diffracted light of a predetermined order among the diffracted light, and the diffracted light that has passed through the optical system. And a light receiving unit for receiving the projected pattern of the interference light.

【００１３】これにより、受光部では、光導波路型回折
格子の屈折率分布に応じて回折した回折光の投影パター
ンを受光することにより、光導波路型回折格子の形状・
構造及び屈折率分布等の光学特性を直接的且つ定量的
に、更に簡易に測定することが可能となる。As a result, the light receiving section receives the projection pattern of the diffracted light diffracted according to the refractive index distribution of the optical waveguide type diffraction grating, and thereby the shape of the optical waveguide type diffraction grating
It becomes possible to directly and quantitatively and easily measure the optical characteristics such as the structure and the refractive index distribution.

【００１４】請求項３に係る発明にあっては、光導波方
向に沿って屈折率の変化分布を有する光導波路型回折格
子を測定する光導波路型回折格子の測定装置において、
光源より放射する光の一部を環状の瞳を有するリング絞
りに通し、前記リング絞りの環状の瞳を通過した光から
生成する参照光を前記光導波方向に対して任意の傾斜角
度の方向より前記光導波路型回折格子に照射する投光系
と、前記参照光が前記光導波路型回折格子によって回折
されると共に透過又は反射してなる回折光を任意の倍率
で拡大する光学系と、前記光学系中に設けられ、前記回
折光のうち所定次数の回折光を位相変調する位相板と、
前記光学系を通過した前記回折光による干渉光の投影パ
ターンを受光する受光部とを具備する構成とした。According to a third aspect of the present invention, there is provided an optical waveguide type diffraction grating measuring device for measuring an optical waveguide type diffraction grating having a refractive index change distribution along an optical waveguide direction.
Part of the light emitted from the light source is passed through a ring diaphragm having an annular pupil, and reference light generated from the light passing through the annular pupil of the ring diaphragm is emitted from a direction having an arbitrary inclination angle with respect to the optical waveguide direction. A light projecting system for irradiating the optical waveguide type diffraction grating, an optical system for enlarging diffracted light formed by transmitting or reflecting the reference light diffracted by the optical waveguide type diffraction grating at an arbitrary magnification, and the optical system A phase plate provided in the system for phase-modulating the diffracted light of a predetermined order among the diffracted lights,
And a light receiving unit for receiving a projection pattern of interference light due to the diffracted light that has passed through the optical system.

【００１５】これにより、受光部では、光導波路型回折
格子の屈折率分布に応じて回折した回折光の投影パター
ンを受光することにより、光導波路型回折格子の形状・
構造及び屈折率分布等の光学特性を直接的且つ定量的
に、更に簡易に測定することが可能となると共に、リン
グ絞りを通過した光による参照光で測定することによ
り、測定生後の向上が図られる。As a result, the light receiving section receives the projection pattern of the diffracted light diffracted according to the refractive index distribution of the optical waveguide type diffraction grating, and thereby the shape of the optical waveguide type diffraction grating
Optical characteristics such as structure and refractive index distribution can be measured directly and quantitatively and more easily, and by measuring with reference light from the light that has passed through the ring diaphragm, improvement in measurement after birth is possible. To be

【００１６】請求項４に係る発明にあっては、請求項１
乃至請求項３のいずれか一項に記載の発明において、前
記受光部で受光された投影パターンの輝度分布に基づい
て前記光導波路型回折格子の特徴を抽出する特徴抽出部
を有する構成とした。According to the invention of claim 4, claim 1
The invention according to any one of claims 1 to 3 is configured to include a feature extraction unit that extracts a feature of the optical waveguide type diffraction grating based on a luminance distribution of a projection pattern received by the light receiving unit.

【００１７】請求項５にかかる発明にあっては、請求項
４に係る発明において、前記特徴抽出部は、前記輝度分
布の最大輝度となる部分と最小輝度となる部分との距離
差に基づいて、前記光導波路型回折格子の前記屈折率の
変化分布のピッチを特徴抽出する構成とした。According to a fifth aspect of the present invention, in the invention according to the fourth aspect, the feature extracting section is based on a distance difference between a maximum brightness portion and a minimum brightness portion of the brightness distribution. The pitch of the change distribution of the refractive index of the optical waveguide type diffraction grating is characteristically extracted.

【００１８】請求項６に係る発明にあっては、請求項４
に係る発明において、前記特徴抽出部は、前記輝度分布
の任意の輝度部分を基準として、前記輝度分布の輝度変
化に基づいて前記光導波路型回折格子の形状、屈折率の
分布、ピッチの少なくとも一つの特徴を抽出する構成と
した。According to the invention of claim 6, claim 4
In the invention according to, the feature extraction unit, based on an arbitrary luminance portion of the luminance distribution, at least one of the shape, the refractive index distribution, and the pitch of the optical waveguide type diffraction grating based on the luminance change of the luminance distribution. It is configured to extract one feature.

【００１９】請求項７に係る発明にあっては、請求項１
乃至請求項３のいずれか一項に記載の発明において、前
記光導波路型回折格子を除いた状態での前記投光系から
前記受光部までの光伝達関数を有し、前記光導波路型回
折格子に係る前記投影パターンを前記光伝達関数で補正
する補正部を有する構成とした。According to the invention of claim 7, claim 1
The invention according to any one of claims 1 to 3, wherein the optical waveguide type diffraction grating has an optical transfer function from the light projecting system to the light receiving section in a state where the optical waveguide type diffraction grating is excluded. It is configured to have a correction unit that corrects the projection pattern according to the above with the light transfer function.

【００２０】請求項８に係る発明にあっては、請求項１
乃至請求項３のいずれか一項に記載の発明において、前
記投光系は、平行光を前記参照光として前記光導波路型
回折格子に照射する構成とした。According to the invention of claim 8, claim 1
In the invention according to any one of claims 3 to 3, the light projecting system irradiates the optical waveguide type diffraction grating with parallel light as the reference light.

【００２１】請求項９に係る発明にあっては、請求項１
乃至請求項３のいずれか一項に記載の発明において、前
記投光系は、実質的に単一波長の参照光を前記光導波路
型回折格子に照射する構成とした。According to the invention of claim 9, claim 1
In the invention according to any one of claims 3 to 3, the light projecting system is configured to irradiate the optical waveguide type diffraction grating with reference light having a substantially single wavelength.

【００２２】請求項１０に係る発明にあっては、請求項
１乃至請求項３のいずれか一項に記載の発明において、
前記光導波路型回折格子は、屈折率整合剤中に浸される
構成とした。According to a tenth aspect of the invention, in the invention according to any one of the first to third aspects,
The optical waveguide type diffraction grating was soaked in a refractive index matching agent.

【００２３】[0023]

【発明の実施の形態】BEST MODE FOR CARRYING OUT THE INVENTION

（第１の実施の形態）図１ないし図６と共に本発明によ
る第１の実施の形態を説明する。尚、図１は測定装置の
概略構成を示す斜視図、図２及び図３は動作を説明する
ための説明図、図４ないし図６は測定原理を説明するた
めの説明図である。(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view showing a schematic configuration of the measuring device, FIGS. 2 and 3 are explanatory diagrams for explaining the operation, and FIGS. 4 to 6 are explanatory diagrams for explaining the measuring principle.

【００２４】図１に基づいて装置構成を説明すると、発
光ダイオードやレーザダイオード等の光源２と、光源２
より放射される光を参照光（平行光）ｈνにするコンデ
ンサレンズ４が設けられている。また、コンデンサレン
ズ４から所定の間隔をおいて対物レンズ６が配置される
と共に、対物レンズ６の後方に２次元撮像が可能なＣＣ
Ｄ固体撮像デバイス８が配置され、更に、ＣＣＤ固体撮
像デバイス８の撮像動作を制御すると共にその撮像動作
によって出力される映像信号Ｓv を入力して後述の信号
処理を行うマイクロコンピュータシステム１０が設けら
れている。The structure of the apparatus will be described with reference to FIG. 1. A light source 2 such as a light emitting diode or a laser diode, and a light source 2
A condenser lens 4 is provided which changes the emitted light to the reference light (parallel light) hν. In addition, the objective lens 6 is arranged at a predetermined distance from the condenser lens 4, and a CC that allows two-dimensional imaging is provided behind the objective lens 6.
A D-solid-state image pickup device 8 is arranged, and a microcomputer system 10 for controlling the image-pickup operation of the CCD solid-state image-pickup device 8 and inputting a video signal Sv output by the image-pickup operation to perform signal processing described later is provided. ing.

【００２５】ここで、光源２とコンデンサレンズ４及び
対物レンズ６が同一の光軸に沿って配置されると共に、
ＣＣＤ固体撮像デバイス８の撮像面がその光軸に対して
直角に向けられており、光源２とコンデンサレンズ４が
参照光ｈνを生じさせる投光系、対物レンズ６が所定の
光学倍率を有する光学系、ＣＣＤ固体撮像デバイス８が
受光部となっている。尚、光軸方向をＺ方向、Ｚ方向に
直交する方向をＹ方向及びＸ方向とする。Here, the light source 2, the condenser lens 4, and the objective lens 6 are arranged along the same optical axis, and
The image pickup surface of the CCD solid-state image pickup device 8 is oriented at right angles to its optical axis, the light source 2 and the condenser lens 4 generate a reference light hν, and the objective lens 6 is an optical element having a predetermined optical magnification. The system and the CCD solid-state imaging device 8 serve as a light receiving portion. The optical axis direction is the Z direction, and the directions orthogonal to the Z direction are the Y direction and the X direction.

【００２６】また、マイクロコンピュータシステム１０
は、上記投光系から受光部までのＭＴＦ（modulation t
ransfer function）とＰＴＦ（phase transfer functio
n ）の両者又は一方を予め記憶しており、これらのＭＴ
ＦとＰＴＦに基づいてＣＣＤ固体撮像デバイス８からの
映像信号Ｓv を補正することによって、上記投光系から
受光部までの特性を補正すると共に、この補正された映
像信号について所定の信号処理を行うことにより、光導
波路型回折格子の特徴抽出を行う。尚、これらのＭＴＦ
とＰＴＦを光伝達関数と総称することとする。Further, the microcomputer system 10
Is the MTF (modulation t) from the light emitting system to the light receiving unit.
ransfer function) and PTF (phase transfer functio)
n) or both of them are stored in advance, and these MTs are stored.
By correcting the video signal Sv from the CCD solid-state imaging device 8 based on F and PTF, the characteristics from the light projecting system to the light receiving unit are corrected, and predetermined signal processing is performed on the corrected video signal. By doing so, the feature extraction of the optical waveguide type diffraction grating is performed. In addition, these MTF
And PTF are collectively referred to as an optical transfer function.

【００２７】そして、測定時には、屈折率整合剤１４中
に密封した光導波路型回折格子１２がコンデンサレンズ
４と対物レンズ６の間に挿入され、参照光ｈνを光導波
路型回折格子１２の一側面より照射させる。At the time of measurement, the optical waveguide type diffraction grating 12 sealed in the refractive index matching agent 14 is inserted between the condenser lens 4 and the objective lens 6, and the reference light hν is supplied to one side of the optical waveguide type diffraction grating 12. More irradiation.

【００２８】次に、図２及び図６に基づいて装置の動作
及び測定原理を説明する。尚、図１０と共に説明した光
ファイバを用いた光導波路型回折格子１２、即ち、光フ
ァイバのクラッド１２ｂ中のコア１２ａにその長手方向
Ｘに沿って屈折率変化部ＣＰ１，ＣＰ２，ＣＰ３，ＣＰ
４，ＣＰ５……と元々コア１２ａと同じ屈折率の部分Ｃ
Ｎ１，ＣＮ２，ＣＮ３，ＣＮ４……とが交互に配列され
て成る屈折率分布を有する光導波路型回折格子１２を測
定する場合を説明するものとする。Next, the operation and measuring principle of the device will be described with reference to FIGS. The optical waveguide type diffraction grating 12 using the optical fiber described with reference to FIG. 10, that is, the core 12a in the clad 12b of the optical fiber is provided along the longitudinal direction X with the refractive index changing portions CP1, CP2, CP3, CP.
4, CP5 ... and the part C having the same refractive index as the core 12a originally.
A case of measuring the optical waveguide type diffraction grating 12 having a refractive index distribution in which N1, CN2, CN3, CN4, ... Are alternately arranged will be described.

【００２９】まず、光導波路型回折格子１２をそのクラ
ッド１２ｂと等しい屈折率の屈折率整合剤１４中に密封
して、コンデンサレンズ４と対物レンズ６の間に配置す
る。この際、光導波路型回折格子１２を上記屈折率分布
の方向Ｘに対して参照光ｈνの照射方向が直角となるよ
うに配置する。First, the optical waveguide type diffraction grating 12 is sealed in a refractive index matching agent 14 having the same refractive index as that of the cladding 12b, and is arranged between the condenser lens 4 and the objective lens 6. At this time, the optical waveguide type diffraction grating 12 is arranged so that the irradiation direction of the reference light hν is at right angles to the direction X of the refractive index distribution.

【００３０】これにより、平行光である参照光ｈνが光
導波路型回折格子１２の一側面より直角に照射すると共
に、屈折率整合剤１４及びクラッド１２ｂを透過する参
照光ｈνはそのまま対物レンズ６へ直進し、上記屈折率
分布を有するコア１２ａ中を透過する参照光ｈνがその
屈折率分布に伴って屈折されて対物レンズ６へ伝搬し、
これらの透過光は対物レンズ６を介してＣＣＤ固体撮像
デバイス８の受光面に投影パターンとして投影される。As a result, the reference light hν, which is parallel light, is emitted from one side surface of the optical waveguide type diffraction grating 12 at a right angle, and the reference light hν transmitted through the refractive index matching agent 14 and the clad 12b is directly applied to the objective lens 6. The reference light hν which goes straight and is transmitted through the core 12a having the above-mentioned refractive index distribution is refracted along with the refractive index distribution and propagates to the objective lens 6,
These transmitted lights are projected as a projection pattern on the light receiving surface of the CCD solid-state imaging device 8 via the objective lens 6.

【００３１】図２は屈折率変化部ＣＰ１，ＣＰ２，ＣＰ
３，ＣＰ４，ＣＰ５……を透過する参照光ｈνの光路を
示し、図３は元々コア１２ａと同じ屈折率の部分ＣＮ
１，ＣＮ２，ＣＮ３，ＣＮ４……を透過する参照光ｈν
の光路を示す。これらの図から明らかなように、部分Ｃ
Ｎ１，ＣＮ２，ＣＮ３，ＣＮ４の各屈折率ｎ2 よりも屈
折率変化部ＣＰ１，ＣＰ２，ＣＰ３，ＣＰ４，ＣＰ５…
…の各屈折率ｎ1 の方が高いので、屈折率変化部ＣＰ
１，ＣＰ２，ＣＰ３，ＣＰ４，ＣＰ５…を透過する参照
光ｈνの方が大きな屈折角で屈折される。FIG. 2 shows the refractive index changing portions CP1, CP2, CP.
3, CP4, CP5 ... Shows the optical path of the reference light hν, and FIG. 3 shows a portion CN originally having the same refractive index as the core 12a.
Reference light hν transmitted through 1, CN2, CN3, CN4 ...
Shows the optical path of. As is clear from these figures, part C
N1, CN2, CN3, the refractive index change portion CP1 than the refractive index n 2 of CN4, CP2, CP3, CP4, CP5 ...
Since each refractive index n 1 of ... Is higher, the refractive index changing portion CP
The reference light hν transmitted through 1, CP2, CP3, CP4, CP5 ... Is refracted at a larger refraction angle.

【００３２】この結果、図４に示す如く、ＣＣＤ固体撮
像デバイス８の受光面には、屈折率変化部ＣＰ１，ＣＰ
２，ＣＰ３，ＣＰ４，ＣＰ５……を通過してなる屈折光
の投影パターンＰ１，Ｐ２，Ｐ３，Ｐ４，Ｐ５……と、
元々コア１２ａと同じ屈折率の部分ＣＮ１，ＣＮ２，Ｃ
Ｎ３，ＣＮ４……を通過してなる屈折光の投影パターン
Ｎ１，Ｎ２，Ｎ３，Ｎ４……と、クラッド１２ｂ及び屈
折率整合剤１４を直進した透過光ｈνによる投影パター
ンＫＵ，ＫＬが投影される。As a result, as shown in FIG. 4, on the light receiving surface of the CCD solid-state image pickup device 8, the refractive index changing portions CP1 and CP are formed.
2, CP3, CP4, CP5 ..., and projection patterns P1, P2, P3, P4, P5 ..
The portions CN1, CN2, C originally having the same refractive index as the core 12a
Projection patterns N1, N2, N3, N4, ... Of refracted light passing through N3, CN4 ... And projection patterns KU, KL by the transmitted light hv straightly traveling through the cladding 12b and the index matching agent 14. .

【００３３】ここで、屈折率変化部ＣＰ１，ＣＰ２，Ｃ
Ｐ３，ＣＰ４，ＣＰ５……と元々コア１２ａと同じ屈折
率の部分ＣＮ１，ＣＮ２，ＣＮ３，ＣＮ４……の夫々の
屈折率ｎ1 ，ｎ2 に起因して屈折光の密度分布が異なる
ので、投影パターンＰ１，Ｐ２，Ｐ３，Ｐ４，Ｐ５……
及びＮ１，Ｎ２，Ｎ３，Ｎ４……と投影パターンＫＵ，
ＫＬとの境界部分（クラッド１２ｂとコア１２ａの境界
部分に相当する）に、薄暗い投影パターンＰＣＵ，ＰＣ
Ｌが現れる。Here, the refractive index changing portions CP1, CP2, C
The density distribution of the refracted light differs due to the refractive indexes n 1 and n 2 of P3, CP4, CP5, ... And the portions CN1, CN2, CN3, CN4 ,. Patterns P1, P2, P3, P4, P5 ...
And N1, N2, N3, N4 ... And the projection pattern KU,
Dim projection patterns PCU, PC on the boundary with KL (corresponding to the boundary between the clad 12b and the core 12a).
L appears.

【００３４】更に、屈折率ｎ1 ＞ｎ2 に起因して、投影
パターンＰ１，Ｐ２，Ｐ３，Ｐ４，Ｐ５……の夫々の幅
ＬP と投影パターンＮ１，Ｎ２，Ｎ３，Ｎ４……の夫々
の幅ＬN が異なると共に、薄暗い投影パターンＰＣＵ，
ＰＣＬと投影パターンＰ１，Ｐ２，Ｐ３，Ｐ４，Ｐ５…
…の夫々の境界部分にも暗い投影パターンＰＣＵ，ＰＣ
Ｌが現れる。Further, due to the refractive index n 1 > n 2 , the width L P of each of the projection patterns P1, P2, P3, P4, P5 ... And the projection patterns N1, N2, N3, N4. with width L N are different, dim projection pattern PCU,
PCL and projection patterns P1, P2, P3, P4, P5 ...
Dark projection pattern PCU, PC on each boundary of
L appears.

【００３５】よって、投影パターンＰ２に該当する部分
のＹP −ＹP ’断面の輝度分布と投影パターンＮ２に該
当する部分のＹN −ＹN ’断面の輝度分布を夫々代表し
て示すと、図５と図６のようになり、光導波路型回折格
子の屈折率分布の特徴を現す投影パターンが得られるこ
とになる。[0035] Therefore, when showing the brightness distribution in the cross section 'Y N -Y N of the luminance distribution and a portion corresponding to the projected pattern N2 sectional' Y P -Y P of the portion corresponding to the projection pattern P2 respectively representatively, As shown in FIGS. 5 and 6, it is possible to obtain a projection pattern that represents the characteristics of the refractive index distribution of the optical waveguide type diffraction grating.

【００３６】ＣＣＤ固体撮像デバイス８は、かかる投影
パターンを２次元撮像し映像信号Ｓv をマイクロコンピ
ュータシステム１０へ転送する。The CCD solid-state image pickup device 2 takes a two-dimensional image of the projection pattern and transfers the video signal Sv to the microcomputer system 10.

【００３７】マイクロコンピュータシステム１０は、光
伝達関数に基づいて映像信号Ｓv を補正処理することに
より、光導波路型回折格子の屈折率分布の特徴をより正
確に現す映像信号Ｓv ’を内部作成し、更に、この映像
信号Ｓv ’について信号処理することにより、光導波路
型回折格子１２の屈折率分布の特徴を抽出する。即ち、
映像信号Ｓv ’は図４乃至図６に示した投影パターンの
輝度分布の情報を有し、且つ輝度分布の情報は光導波路
型回折格子１２の屈折率分布と対応しているので、輝度
分布の情報に基づいて、屈折率分布の形状や、屈折率分
布の各部分の屈折率を演算する。The microcomputer system 10 internally corrects the video signal Sv based on the optical transfer function to internally generate a video signal Sv 'which more accurately expresses the characteristics of the refractive index distribution of the optical waveguide type diffraction grating, Further, the characteristics of the refractive index distribution of the optical waveguide type diffraction grating 12 are extracted by performing signal processing on this video signal Sv '. That is,
The image signal Sv 'has information on the brightness distribution of the projection pattern shown in FIGS. 4 to 6, and since the information on the brightness distribution corresponds to the refractive index distribution of the optical waveguide type diffraction grating 12, the brightness distribution The shape of the refractive index distribution and the refractive index of each part of the refractive index distribution are calculated based on the information.

【００３８】例えば、図４乃至図６に示した暗いパター
ンＮＣＵ，ＮＣＬ，ＰＣＵ，ＰＣＬの位置情報を基準に
して、明るい部分Ｐ１，Ｐ２，Ｐ３，Ｐ４，Ｐ５……と
Ｎ１，Ｎ２，Ｎ３，Ｎ４……の夫々の幅ＬN ，ＬP を演
算すると共に、幅ＬN ，ＬPの段差位置の情報から屈折
率変化部ＣＰ１，ＣＰ２，ＣＰ３，ＣＰ４，ＣＰ５……
と元々コア１２ａと同じ屈折率の部分ＣＮ１，ＣＮ２，
ＣＮ３，ＣＮ４……の夫々のＸ方向の長さを演算するこ
とによって、これらの各部分ＣＰ１，ＣＰ２，ＣＰ３，
ＣＰ４，ＣＰ５……とＣＮ１，ＣＮ２，ＣＮ３，ＣＮ４
……の形状を特徴抽出する。For example, based on the positional information of the dark patterns NCU, NCL, PCU, PCL shown in FIGS. 4 to 6, the bright portions P1, P2, P3, P4, P5 ... And N1, N2, N3. The respective widths L N and L P of N4 ... Are calculated, and the refractive index changing portions CP1, CP2, CP3, CP4, CP5 ... From the information of the step positions of the widths L N and L P.
And portions CN1, CN2 having the same refractive index as the core 12a originally.
By calculating the length of each of CN3, CN4, ... In the X direction, each of these parts CP1, CP2, CP3,
CP4, CP5 ... and CN1, CN2, CN3, CN4
The feature of the shape is extracted.

【００３９】また、このようにして求められた各部分Ｃ
Ｐ１，ＣＰ２，ＣＰ３，ＣＰ４，ＣＰ５……とＣＮ１，
ＣＮ２，ＣＮ３，ＣＮ４……の輝度分布の情報に基づい
て、夫々の屈折率を特徴抽出する。Further, each portion C thus obtained
P1, CP2, CP3, CP4, CP5 ... and CN1,
Based on the information of the luminance distribution of CN2, CN3, CN4 ..., Each refractive index is feature-extracted.

【００４０】更にまた、このようにして求められた各部
分ＣＰ１，ＣＰ２，ＣＰ３，ＣＰ４，ＣＰ５……とＣＮ
１，ＣＮ２，ＣＮ３，ＣＮ４……の輝度分布の最大輝度
の位置又は最低輝度を演算して、各部分間のピッチを特
徴抽出する。Furthermore, the respective parts CP1, CP2, CP3, CP4, CP5, ... And CN thus obtained are
The position of the maximum brightness or the minimum brightness of the brightness distribution of 1, CN2, CN3, CN4 ... Is calculated to extract the pitch between the respective parts as a feature.

【００４１】そして、マイクロコンピュータシステム１
０からモニター等の外部表示装置（図示せず）へ、特徴
抽出データや映像信号Ｓv ’を出力することによって、
測定結果を表示させる。Then, the microcomputer system 1
By outputting the feature extraction data or the video signal Sv 'from 0 to an external display device (not shown) such as a monitor,
Display the measurement results.

【００４２】このように、この第１の実施の形態によれ
ば、光導波路型回折格子の形状・構造及び光学特性を直
接的且つ定量的に、更に簡易に測定することができる光
導波路型回折格子の測定装置を提供することができる。As described above, according to the first embodiment, it is possible to measure the shape / structure and the optical characteristics of the optical waveguide type diffraction grating directly and quantitatively and more easily. A grid measuring device can be provided.

【００４３】尚、上記参照光ｈνの波長については特に
限定するものではないが、単一波長光を適用しても良
い。また、参照光ｈνを光導波型回折格子に側面照射し
たときの透過光の投影パターンについて測定する測定装
置を説明したが、光導波型回折格子に側面照射したとき
の反射光の投影パターンについて測定する構成としても
良い。更にまた、光ファイバを用いた光導波型回折格子
の測定について説明したが、かかる光導波型回折格子の
測定に限らず、他種類の光導波型回折格子の測定も可能
である。The wavelength of the reference light hν is not particularly limited, but a single wavelength light may be applied. Further, the measurement device for measuring the projection pattern of the transmitted light when the reference light hν is side-illuminated to the optical waveguide type diffraction grating has been described, but the projection pattern of the reflected light when side-illuminated to the optical waveguide type diffraction grating is measured. It may be configured to. Furthermore, the measurement of the optical waveguide type diffraction grating using the optical fiber has been described, but the measurement is not limited to such an optical waveguide type diffraction grating, and other types of optical waveguide type diffraction gratings can be measured.

【００４４】（第２の実施の形態）図７ないし図９と共
に第２の実施の形態を説明する。尚、図７は測定装置の
概略構成を示す断面図、図８及び図９は動作及び測定原
理を説明するための説明図である。(Second Embodiment) A second embodiment will be described with reference to FIGS. 7 to 9. 7. FIG. 7 is a sectional view showing a schematic configuration of the measuring device, and FIGS. 8 and 9 are explanatory views for explaining the operation and the measuring principle.

【００４５】図７に基づいて装置構成を説明すると、光
源（図示せず）と環状の瞳１６ａが設けられたリング絞
り１６とコンデンサレンズ１８とを有する投光系と、対
物レンズ２０及び位相板２２を有する光学系と、２次元
撮像が可能なＣＣＤ固体撮像デバイス２４を有する撮像
部が配置され、更に、ＣＣＤ固体撮像デバイス２４の撮
像動作を制御すると共にその撮像動作によって出力され
る映像信号Ｓv を入力して後述の信号処理を行うマイク
ロコンピュータシステム２６が設けられている。The structure of the apparatus will be described with reference to FIG. 7. A light projection system having a light source (not shown), a ring diaphragm 16 provided with an annular pupil 16a, and a condenser lens 18, an objective lens 20 and a phase plate. An optical system having 22 and an image pickup unit having a CCD solid-state image pickup device 24 capable of two-dimensional image pickup are arranged, and further, the image pickup operation of the CCD solid-state image pickup device 24 is controlled, and a video signal Sv outputted by the image pickup operation. A microcomputer system 26 is provided for inputting the input signal and performing signal processing described later.

【００４６】ここで、上記光源とコンデンサレンズ１８
及び対物レンズ２０が同一の光軸に沿って配置されると
共に、ＣＣＤ固体撮像デバイス２４の撮像面がその光軸
に対して直角に向けられている。更に、コンデンサレン
ズ１８と対物レンズ２０との対向間隔と、対物レンズ２
０と位相板２２との対向間隔を光軸に沿って任意に微調
整することができるようになっている。尚、光軸方向を
Ｚ方向、Ｚ方向に直交する方向をＹ方向及びＸ方向とす
る。Here, the light source and the condenser lens 18
The objective lens 20 is arranged along the same optical axis, and the image pickup surface of the CCD solid-state image pickup device 24 is oriented at a right angle to the optical axis. Furthermore, the opposing distance between the condenser lens 18 and the objective lens 20 and the objective lens 2
The facing distance between 0 and the phase plate 22 can be arbitrarily adjusted along the optical axis. The optical axis direction is the Z direction, and the directions orthogonal to the Z direction are the Y direction and the X direction.

【００４７】また、マイクロコンピュータシステム２６
は、上記投光系から受光部までのＭＴＦ（modulation t
ransfer function）とＰＴＦ（phase transfer functio
n ）の両者又は一方を予め記憶しており、これらのＭＴ
ＦとＰＴＦに基づいてＣＣＤ固体撮像デバイス８からの
映像信号Ｓv を補正することによって、上記投光系から
受光部までの特性を補正すると共に、この補正された映
像信号について所定の信号処理を行うことにより、光導
波路型回折格子の特徴抽出を行う。Further, the microcomputer system 26
Is the MTF (modulation t) from the light emitting system to the light receiving unit.
ransfer function) and PTF (phase transfer functio)
n) or both of them are stored in advance, and these MTs are stored.
By correcting the video signal Sv from the CCD solid-state imaging device 8 based on F and PTF, the characteristics from the light projecting system to the light receiving unit are corrected, and predetermined signal processing is performed on the corrected video signal. By doing so, the feature extraction of the optical waveguide type diffraction grating is performed.

【００４８】そして、測定時には、屈折率整合剤２８中
に密封した光導波路型回折格子３０がコンデンサレンズ
１８と対物レンズ２０の間に挿入され、対物レンズ２０
を通過する参照光ｈνを光導波路型回折格子３０の一側
面より照射させる。At the time of measurement, the optical waveguide type diffraction grating 30 sealed in the refractive index matching agent 28 is inserted between the condenser lens 18 and the objective lens 20, and the objective lens 20
The reference light hν that passes through is emitted from one side surface of the optical waveguide diffraction grating 30.

【００４９】次に、図７乃至図９に基づいて装置の動作
及び測定原理を説明する。尚、図１０と共に説明した光
ファイバを用いた光導波路型回折格子３０、即ち、光フ
ァイバのクラッド３０ｂ中のコア３０ａにその長手方向
Ｘに沿って屈折率変化部ＣＰ１，ＣＰ２，ＣＰ３，ＣＰ
４，ＣＰ５……と元々コア３０ａと同じ屈折率の部分Ｃ
Ｎ１，ＣＮ２，ＣＮ３，ＣＮ４……とが交互に配列され
て成る屈折率分布を有する光導波路型回折格子３０を測
定する場合を説明するものとする。Next, the operation of the device and the principle of measurement will be described with reference to FIGS. The optical waveguide type diffraction grating 30 using the optical fiber described with reference to FIG. 10, that is, the core 30a in the clad 30b of the optical fiber is provided along the longitudinal direction X with the refractive index changing portions CP1, CP2, CP3, CP.
4, CP5 ... and the part C originally having the same refractive index as the core 30a.
A case of measuring an optical waveguide type diffraction grating 30 having a refractive index distribution in which N1, CN2, CN3, CN4 ... Are alternately arranged will be described.

【００５０】まず、光導波路型回折格子３０をそのクラ
ッド３０ｂと等しい屈折率の屈折率整合剤２８中に密封
して、コンデンサレンズ１８と対物レンズ２０の間に配
置する。この際、光導波路型回折格子３０の上記屈折率
分布の方向Ｘと光軸方向Ｚとが直角となるように、光導
波路型回折格子３０を配置する。First, the optical waveguide type diffraction grating 30 is sealed in a refractive index matching agent 28 having the same refractive index as that of the clad 30b, and is arranged between the condenser lens 18 and the objective lens 20. At this time, the optical waveguide type diffraction grating 30 is arranged so that the direction X of the refractive index distribution of the optical waveguide type diffraction grating 30 is perpendicular to the optical axis direction Z.

【００５１】前記投光系中の光源（図示せず）から放射
される光の一部だけがリング絞り１６の環状の瞳１６ａ
を通過することによって、環状の光がコンデンサレンズ
１８に入射し、この光がコンデンサレンズ１８を通過す
ることによって平行光（参照光）ｈνとなる。これによ
り、環状且つ平行光である参照光ｈνが、コンデンサレ
ンズ１８から光導波路型回折格子３０に向けて適宜の角
度をもって照射する。Only part of the light emitted from the light source (not shown) in the projection system is an annular pupil 16a of the ring diaphragm 16.
The circular light is made incident on the condenser lens 18 by passing through, and becomes parallel light (reference light) hν by passing through the condenser lens 18. As a result, the reference light hν which is an annular and parallel light is emitted from the condenser lens 18 toward the optical waveguide type diffraction grating 30 at an appropriate angle.

【００５２】図７中には照射光ｈνの光路の一部を代表
して示すが、参照光ｈνが光導波路型回折格子３０を通
過する際に、コア３０ａ中に形成されている上記屈折率
分布に伴って回折し、この回折光が所定倍率の対物レン
ズ２０ないし位相板２２を通ってＣＣＤ固体撮像デバイ
ス２４の受光面に投影される。FIG. 7 shows a part of the optical path of the irradiation light hν as a representative, but when the reference light hν passes through the optical waveguide type diffraction grating 30, the above-mentioned refractive index formed in the core 30a. The light is diffracted according to the distribution, and the diffracted light is projected on the light receiving surface of the CCD solid-state image pickup device 24 through the objective lens 20 or the phase plate 22 having a predetermined magnification.

【００５３】ここで、位相板２２には、回折光のうちの
０次回折光（図中、実線にて示す）の通過位置に、０次
回折光の透過光量及び移動を適宜に調節する為の環状の
位相膜２２ａが設けられており、位相膜２２ａ以外の部
分を透過する高次の回折光（図中、点線にて示す）と位
相膜２２ａを透過した０次回折光がＣＣＤ固体撮像デバ
イス２４の受光面で相互に干渉し合う。したがって、こ
の干渉により、回折光がより鮮明な干渉光の投影パター
ンとして受光される。Here, the phase plate 22 has an annular shape for appropriately adjusting the amount and movement of the 0th-order diffracted light at the passing position of the 0th-order diffracted light (shown by the solid line in the figure) of the diffracted light. Of the CCD solid-state imaging device 24, the high-order diffracted light (shown by a dotted line in the drawing) that transmits the portion other than the phase film 22a and the 0th-order diffracted light that has passed through the phase film 22a The light receiving surfaces interfere with each other. Therefore, due to this interference, the diffracted light is received as a clearer projection pattern of the interference light.

【００５４】また、屈折率整合剤２８及びクラッド３０
ｂに入射する参照光ｈνはそのまま直進し、対物レンズ
２０及び位相板２２を介してＣＣＤ固体撮像デバイス２
４に受光される。Further, the refractive index matching agent 28 and the clad 30
The reference light hν incident on b travels straight as it is, and passes through the objective lens 20 and the phase plate 22 to the CCD solid-state imaging device 2
4 is received.

【００５５】この結果、図８に示す如く、ＣＣＤ固体撮
像デバイス２４の受光面には、上記干渉によりＸ方向に
そって周期的に輝度が変化する輝度分布パターンＦＰ，
ＦＮと、これらの輝度分布バターンＦＰ，ＦＮの上下位
置に現れる輝度パターンＦＫＵ，ＦＫＬが投影される。
尚、例えば、輝度分布パターンＦＰは、光導波路型回折
格子３０の屈折率分布のうちの屈折率変化部ＣＰ１，Ｃ
Ｐ２，ＣＰ３，ＣＰ４，ＣＰ５……に対応して発生し、
輝度分布パターンＦＮは、元々コア３０ａと同じ屈折率
の部分ＣＮ１，ＣＮ２，ＣＮ３，ＣＮ４……に対応して
発生し、輝度パターンＦＫＵ，ＦＫＬは、屈折率整合剤
２８及びクラッド３０ｂを透過・直進する光によって発
生する。As a result, as shown in FIG. 8, on the light receiving surface of the CCD solid-state image pickup device 24, the luminance distribution pattern FP, whose luminance changes periodically along the X direction due to the interference,
The FN and the luminance patterns FKU and FKL appearing at the upper and lower positions of the luminance distribution patterns FP and FN are projected.
Note that, for example, the brightness distribution pattern FP has the refractive index changing portions CP1 and C in the refractive index distribution of the optical waveguide type diffraction grating 30.
It occurs corresponding to P2, CP3, CP4, CP5 ...
The luminance distribution pattern FN is originally generated corresponding to the portions CN1, CN2, CN3, CN4 ... Having the same refractive index as the core 30a, and the luminance patterns FKU and FKL are transmitted through the refractive index matching agent 28 and the clad 30b and go straight. It is generated by the light.

【００５６】更に、位相板２２及び位相膜２２ａの位相
特性を調節すれば、０次回折光の位相を進めたり逆に遅
らせることとなるので、上記の干渉を調整することがで
き、鮮明なコントラストの輝度分布パターンＦＰ，ＦＮ
を得ることができる。Furthermore, if the phase characteristics of the phase plate 22 and the phase film 22a are adjusted, the phase of the 0th-order diffracted light is advanced or delayed, so that the above interference can be adjusted and a clear contrast can be obtained. Luminance distribution pattern FP, FN
Can be obtained.

【００５７】図９は、輝度分布パターンＦＰ，ＦＮの輝
度をＸ方向に沿って示した図であり、輝度分布の最大値
の間隔又は最小値の間隔Δが屈折率分布のピッチに対応
する。FIG. 9 is a diagram showing the luminance of the luminance distribution patterns FP and FN along the X direction. The maximum value interval or the minimum value interval Δ of the brightness distribution corresponds to the pitch of the refractive index distribution.

【００５８】ＣＣＤ固体撮像デバイス２４は、かかる投
影パターンを２次元撮像し映像信号Ｓv をマイクロコン
ピュータシステム２６へ転送する。The CCD solid-state image pickup device 24 two-dimensionally picks up the projection pattern and transfers the video signal Sv to the microcomputer system 26.

【００５９】マイクロコンピュータシステム２６は、光
伝達関数に基づいて映像信号Ｓv を補正処理することに
より、光導波路型回折格子の屈折率分布の特徴をより正
確に現す映像信号Ｓv ’を内部作成し、更に、この映像
信号Ｓv ’について信号処理することにより、光導波路
型回折格子３０の屈折率分布の特徴を抽出する。即ち、
映像信号Ｓv ’は図８乃至図９に示した投影パターンの
輝度分布の情報を有し、且つ輝度分布の情報は光導波路
型回折格子３０の屈折率分布と対応しているので、輝度
分布の情報に基づいて、屈折率分布の形状や、屈折率分
布の各部分の屈折率を演算する。The microcomputer system 26 corrects the video signal Sv based on the optical transfer function to internally generate a video signal Sv 'which more accurately expresses the characteristics of the refractive index distribution of the optical waveguide type diffraction grating, Further, the characteristics of the refractive index distribution of the optical waveguide type diffraction grating 30 are extracted by performing signal processing on this video signal Sv '. That is,
The video signal Sv 'has information on the brightness distribution of the projection pattern shown in FIGS. 8 to 9, and since the information on the brightness distribution corresponds to the refractive index distribution of the optical waveguide type diffraction grating 30, the brightness distribution The shape of the refractive index distribution and the refractive index of each part of the refractive index distribution are calculated based on the information.

【００６０】例えば、図８に示したパターンＦＫＵ，Ｆ
ＫＬとパターンＦＰ，ＦＮとの明暗の境界部分を基準に
して、屈折率分布の形状や、屈折率分布の各部分の屈折
率を演算したり、図９に示した輝度分布に基づいて、屈
折率分布のピッチや各部の屈折率を演算する。For example, the patterns FKU and F shown in FIG.
Based on the light and dark boundary portion between KL and the patterns FP and FN, the shape of the refractive index distribution and the refractive index of each portion of the refractive index distribution are calculated, and the refractive index is calculated based on the brightness distribution shown in FIG. The pitch of the index distribution and the refractive index of each part are calculated.

【００６１】そして、マイクロコンピュータシステム３
０からモニター等の外部表示装置（図示せず）へ、特徴
抽出データや映像信号Ｓv ’を出力することによって、
測定結果を表示させる。Then, the microcomputer system 3
By outputting the feature extraction data or the video signal Sv 'from 0 to an external display device (not shown) such as a monitor,
Display the measurement results.

【００６２】このように、この第２の実施の形態によれ
ば、光導波路型回折格子の形状・構造及び光学特性を直
接的且つ定量的に、更に簡易に測定することができる光
導波路型回折格子の測定装置を提供することができる。As described above, according to the second embodiment, it is possible to measure the shape and structure of the optical waveguide type diffraction grating and the optical characteristics directly and quantitatively and more easily. A grid measuring device can be provided.

【００６３】尚、上記参照光ｈνの波長については特に
限定するものではないが、単一波長光を適用しても良
い。また、参照光ｈνを光導波型回折格子に側面照射し
たときの透過光の投影パターンについて測定する測定装
置を説明したが、光導波型回折格子に側面照射したとき
の反射光の投影パターンについて測定する構成としても
良い。更にまた、光ファイバを用いた光導波型回折格子
の測定について説明したが、かかる光導波型回折格子の
測定に限らず、他種類の光導波型回折格子の測定も可能
である。The wavelength of the reference light hν is not particularly limited, but single wavelength light may be applied. Further, the measurement device for measuring the projection pattern of the transmitted light when the reference light hν is side-illuminated to the optical waveguide type diffraction grating has been described, but the projection pattern of the reflected light when side-illuminated to the optical waveguide type diffraction grating is measured. It may be configured to. Furthermore, the measurement of the optical waveguide type diffraction grating using the optical fiber has been described, but the measurement is not limited to such an optical waveguide type diffraction grating, and other types of optical waveguide type diffraction gratings can be measured.

【００６４】また、リング絞り１６を備えた装置構成を
説明したが、これに限定されるものではなく、平行光で
ある参照光ｈνを光導波路型回折格子に対して適宜の角
度で照射させる構成ならば、本発明に含まれるものであ
る。The structure of the device provided with the ring diaphragm 16 has been described. However, the structure is not limited to this, and the reference light hν which is parallel light is irradiated onto the optical waveguide type diffraction grating at an appropriate angle. Then, it is included in the present invention.

【００６５】[0065]

【発明の効果】以上説明したように本発明によれば、被
検体である光導波路回折格子を本装置に配置するだけで
簡易に、その形状や構造、屈折率分布等を直接的且つ定
量的に測定することができるという優れた効果を発揮す
る。As described above, according to the present invention, the shape, structure, refractive index distribution, etc. of the optical waveguide diffraction grating which is the subject can be directly and quantitatively simply by arranging it in this device. It has an excellent effect that it can be measured.

【図面の簡単な説明】[Brief description of drawings]

【図１】第１の実施の形態の装置構成を示す斜視図であ
る。FIG. 1 is a perspective view showing a device configuration of a first embodiment.

【図２】第１の実施の形態の動作を説明するための説明
図である。FIG. 2 is an explanatory diagram for explaining the operation of the first embodiment.

【図３】第１の実施の形態の動作を更に説明するための
説明図である。FIG. 3 is an explanatory diagram for further explaining the operation of the first embodiment.

【図４】第１の実施の形態の測定原理を説明するための
説明図である。FIG. 4 is an explanatory diagram for explaining the measurement principle of the first embodiment.

【図５】第１の実施の形態の測定原理を更に説明するた
めの説明図である。FIG. 5 is an explanatory diagram for further explaining the measurement principle of the first embodiment.

【図６】第１の実施の形態の測定原理を更に説明するた
めの説明図である。FIG. 6 is an explanatory diagram for further explaining the measurement principle of the first embodiment.

【図７】第２の実施の形態の装置構成及び動作を説明す
るための断面図である。FIG. 7 is a cross-sectional view for explaining the device configuration and operation of the second embodiment.

【図８】第２の実施の形態の測定原理を説明するための
説明図である。FIG. 8 is an explanatory diagram for explaining the measurement principle of the second embodiment.

【図９】第２の実施の形態の測定原理を更に説明するた
めの説明図である。FIG. 9 is an explanatory diagram for further explaining the measurement principle of the second embodiment.

【図１０】光導波路型回折格子の構造を示す部分縦断面
図である。FIG. 10 is a partial vertical cross-sectional view showing the structure of an optical waveguide type diffraction grating.

【符号の説明】[Explanation of symbols]

２…光源、４…コンデンサレンズ、６…対物レンズ、８
…ＣＣＤ固体撮像デバイス、１０…マイクロコンピュー
タシステム、１２…光導波路型回折格子、１２ａ…屈折
率分布を有するコア、１２ｂ…クラッド、１４…屈折率
整合剤、１６…リング絞り、１８…コンデンサレンズ、
２０…対物レンズ、２２…位相板、２２ａ…位相膜、２
４…ＣＣＤ固体撮像デバイス、２６…マイクロコンピュ
ータシステム。2 ... Light source, 4 ... Condenser lens, 6 ... Objective lens, 8
... CCD solid-state imaging device, 10 ... Microcomputer system, 12 ... Optical waveguide type diffraction grating, 12a ... Core having a refractive index distribution, 12b ... Clad, 14 ... Refractive index matching agent, 16 ... Ring diaphragm, 18 ... Condenser lens,
20 ... Objective lens, 22 ... Phase plate, 22a ... Phase film, 2
4 ... CCD solid-state imaging device, 26 ... Microcomputer system.

Claims (10)

【特許請求の範囲】[Claims] 【請求項１】 光導波方向に沿って屈折率の変化分布を
有する光導波路型回折格子を測定する光導波路型回折格
子の測定装置において、 前記光導波方向に対して直交する方向より前記光導波路
型回折格子に参照光を照射する投光系と、 前記参照光が前記屈折率の変化分布に応じて屈折される
と共に透過又は反射してなる屈折光を任意の倍率で拡大
する光学系と、 前記光学系を通過した前記屈折光の投影パターンを受光
する受光部と、を具備することを特徴とする光導波路型
回折格子の測定装置。1. An optical waveguide type diffraction grating measuring device for measuring an optical waveguide type diffraction grating having a refractive index change distribution along the optical waveguide direction, wherein the optical waveguide is arranged in a direction orthogonal to the optical waveguide direction. A projection system for irradiating a type diffraction grating with reference light, and an optical system for magnifying refracted light, which is refracted and transmitted or reflected by the reference light according to the change distribution of the refractive index, at an arbitrary magnification, An optical waveguide type diffraction grating measuring device, comprising: a light receiving unit that receives a projection pattern of the refracted light that has passed through the optical system. 【請求項２】 光導波方向に沿って屈折率の変化分布を
有する光導波路型回折格子を測定する光導波路型回折格
子の測定装置において、 前記光導波方向に対して任意の傾斜角度の方向より前記
光導波路型回折格子に参照光を照射する投光系と、 前記参照光が前記光導波路型回折格子によって回折され
ると共に透過又は反射してなる回折光を任意の倍率で拡
大する光学系と、 前記光学系中に設けられ、前記回折光のうち所定次数の
回折光を位相変調する位相板と、 前記光学系を通過した前記回折光による干渉光の投影パ
ターンを受光する受光部と、を具備することを特徴とす
る光導波路型回折格子の測定装置。2. An optical waveguide type diffraction grating measuring apparatus for measuring an optical waveguide type diffraction grating having a refractive index change distribution along the optical waveguide direction, comprising: A light projecting system for irradiating the optical waveguide type diffraction grating with reference light; and an optical system for enlarging the diffracted light formed by transmitting or reflecting the reference light diffracted by the optical waveguide type diffraction grating at an arbitrary magnification. A phase plate provided in the optical system for phase-modulating diffracted light of a predetermined order among the diffracted light; and a light receiving unit for receiving a projection pattern of interference light due to the diffracted light that has passed through the optical system, An optical waveguide type diffraction grating measuring device comprising: 【請求項３】 光導波方向に沿って屈折率の変化分布を
有する光導波路型回折格子を測定する光導波路型回折格
子の測定装置において、 光源より放射する光の一部を環状の瞳を有するリング絞
りに通し、前記リング絞りの環状の瞳を通過した光から
生成する参照光を前記光導波方向に対して任意の傾斜角
度の方向より前記光導波路型回折格子に照射する投光系
と、 前記参照光が前記光導波路型回折格子によって回折され
ると共に透過又は反射してなる回折光を任意の倍率で拡
大する光学系と、 前記光学系中に設けられ、前記回折光のうち所定次数の
回折光を位相変調する位相板と、 前記光学系を通過した前記回折光による干渉光の投影パ
ターンを受光する受光部と、を具備することを特徴とす
る光導波路型回折格子の測定装置。3. An optical waveguide type diffraction grating measuring apparatus for measuring an optical waveguide type diffraction grating having a refractive index change distribution along an optical waveguide direction, wherein a part of light emitted from a light source has an annular pupil. A light projecting system for irradiating the optical waveguide type diffraction grating through a ring diaphragm, and irradiating the reference light generated from the light passing through the annular pupil of the ring diaphragm from a direction of an arbitrary inclination angle with respect to the optical waveguide direction, An optical system that magnifies diffracted light, which is obtained by transmitting or reflecting the reference light while being diffracted by the optical waveguide type diffraction grating, at an arbitrary magnification, and provided in the optical system and having a predetermined order of the diffracted light. An optical waveguide type diffraction grating measuring apparatus comprising: a phase plate that phase-modulates diffracted light; and a light receiving unit that receives a projection pattern of interference light due to the diffracted light that has passed through the optical system. 【請求項４】 前記受光部で受光された投影パターンの
輝度分布に基づいて前記光導波路型回折格子の特徴を抽
出する特徴抽出部を有することを特徴とする請求項１乃
至請求項３のいずれか一項に記載の光導波路型回折格子
の測定装置。4. The feature extraction unit according to claim 1, further comprising a feature extraction unit that extracts a feature of the optical waveguide type diffraction grating based on a brightness distribution of a projection pattern received by the light receiving unit. 2. An optical waveguide type diffraction grating measuring device according to item 1. 【請求項５】 前記特徴抽出部は、前記輝度分布の最大
輝度となる部分と最小輝度となる部分との距離差に基づ
いて、前記光導波路型回折格子の前記屈折率の変化分布
のピッチを特徴抽出することを特徴とする請求項４に記
載の光導波路型回折格子の測定装置。5. The feature extracting unit determines the pitch of the change distribution of the refractive index of the optical waveguide type diffraction grating based on the difference in distance between the maximum luminance portion and the minimum luminance portion of the luminance distribution. The optical waveguide type diffraction grating measuring apparatus according to claim 4, wherein the characteristic extraction is performed. 【請求項６】 前記特徴抽出部は、前記輝度分布の任意
の輝度部分を基準として、前記輝度分布の輝度変化に基
づいて前記光導波路型回折格子の形状、屈折率の分布、
ピッチの少なくとも一つの特徴を抽出することを特徴と
する請求項４に記載の光導波路型回折格子の測定装置。6. The feature extraction unit, based on an arbitrary luminance portion of the luminance distribution, based on a luminance change of the luminance distribution, a shape of the optical waveguide type diffraction grating, a refractive index distribution,
The optical waveguide type diffraction grating measuring device according to claim 4, wherein at least one feature of the pitch is extracted. 【請求項７】 前記光導波路型回折格子を除いた状態で
の前記投光系から前記受光部までの光伝達関数を有し、
前記光導波路型回折格子に係る前記投影パターンを前記
光伝達関数で補正する補正部を有することを特徴とする
請求項１乃至請求項３のいずれか一項に記載の光導波路
型回折格子の測定装置。7. A light transfer function from the light projecting system to the light receiving section in a state where the optical waveguide type diffraction grating is removed,
The measurement of the optical waveguide type diffraction grating according to claim 1, further comprising a correction unit that corrects the projection pattern of the optical waveguide type diffraction grating with the light transfer function. apparatus. 【請求項８】 前記投光系は、平行光を前記参照光とし
て前記光導波路型回折格子に照射することを特徴とする
請求項１又は請求項３に記載の光導波路型回折格子の測
定装置。8. The optical waveguide type diffraction grating measuring apparatus according to claim 1, wherein the light projecting system irradiates the optical waveguide type diffraction grating with parallel light as the reference light. . 【請求項９】 前記投光系は、実質的に単一波長の参照
光を前記光導波路型回折格子に照射することを特徴とす
る請求項１乃至請求項３の何れか一項に記載の光導波路
型回折格子の測定装置。9. The light projecting system irradiates the optical waveguide type diffraction grating with reference light having a substantially single wavelength, according to any one of claims 1 to 3. Optical waveguide diffraction grating measuring device. 【請求項１０】 前記光導波路型回折格子は、屈折率整
合剤中に浸されることを特徴とする請求項１又は請求項
３の何れか一項に記載の光導波路型回折格子の測定装
置。10. The optical waveguide type diffraction grating measuring apparatus according to claim 1, wherein the optical waveguide type diffraction grating is immersed in a refractive index matching agent. .
JP7182863A 1995-07-19 1995-07-19 Measuring device for optical waveguide type diffraction grating Pending JPH0933393A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7182863A JPH0933393A (en) 1995-07-19 1995-07-19 Measuring device for optical waveguide type diffraction grating

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7182863A JPH0933393A (en) 1995-07-19 1995-07-19 Measuring device for optical waveguide type diffraction grating

Publications (1)

Publication Number Publication Date
JPH0933393A true JPH0933393A (en) 1997-02-07

Family

ID=16125767

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7182863A Pending JPH0933393A (en) 1995-07-19 1995-07-19 Measuring device for optical waveguide type diffraction grating

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Country Link
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011106553A2 (en) * 2010-02-24 2011-09-01 The Regents Of The University Of California Planar, low loss transmitting or reflecting lenses using sub-wavelength high contrast grating
CN108180866A (en) * 2017-12-31 2018-06-19 西北大学 Fiber grating vector curved-ray tracing device
CN110199174A (en) * 2017-01-25 2019-09-03 奥林巴斯株式会社 Light measuring device
CN114364948A (en) * 2019-09-13 2022-04-15 应用材料公司 Measurement system and grating pattern array

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011106553A2 (en) * 2010-02-24 2011-09-01 The Regents Of The University Of California Planar, low loss transmitting or reflecting lenses using sub-wavelength high contrast grating
WO2011106553A3 (en) * 2010-02-24 2012-01-19 The Regents Of The University Of California Planar, low loss transmitting or reflecting lenses using sub-wavelength high contrast grating
US8755118B2 (en) 2010-02-24 2014-06-17 The Regents Of The University Of California Planar, high NA, low loss transmitting or reflecting lenses using sub-wavelength high contrast grating
CN110199174A (en) * 2017-01-25 2019-09-03 奥林巴斯株式会社 Light measuring device
CN108180866A (en) * 2017-12-31 2018-06-19 西北大学 Fiber grating vector curved-ray tracing device
CN108180866B (en) * 2017-12-31 2021-01-01 西北大学 Fiber grating vector bending recognizer
CN114364948A (en) * 2019-09-13 2022-04-15 应用材料公司 Measurement system and grating pattern array
CN114364948B (en) * 2019-09-13 2024-06-11 应用材料公司 Measuring system and grating pattern array

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