JPH01119735A - Interferometer - Google Patents

Abstract

PURPOSE:To perform stable measurement even under the environment such that the vibration is applied to a measuring meter, by dividing luminous flux to be measured into a pair of two luminous fluxes and respectively propagating both luminous fluxes through independent solid closed passages. CONSTITUTION:The luminous flux 2 to be measured emitted from a beam source 1 becomes parallel luminous flux 4 to be incident to an optical fiber bundle 5. The optical fiber bundle 5 is composed of (N) pairs of fiber pairs 6 each consisting of two fibers. One fiber 7 of each fiber pair has an equal beam path length (l) with respect to (N) pairs of fiber pairs 6 and the other fibers 8 are different at every pairs and the beam path length of one fiber of the n-th pair becomes l+(n-N/2)XDELTAl. By this constitution, there is beam path length difference of (n-N/2)XDELTAl between two fibers of the n-th pair and beam path difference is different by DELTAl between the n-th pair and the (n+1)-th pair. The beam from two fibers 7, 8 of each pair is again coupled by a beam coupler 9 to generate interference and detected by the corresponding pixel 11 of a unidimensional multichannel beam detector 10 composed of N-bit pixels. By this method, stable measurement can be performed even under the environ ment such that vibration is applied.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は干渉計に係り、特に一次元または二次元のマル
チチャネル光検出器を干渉図形の検出部に用いる干渉計
に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an interferometer, and more particularly to an interferometer that uses a one-dimensional or two-dimensional multichannel photodetector as an interferogram detection section.

〔従来の技術〕[Conventional technology]

従来の一次元または二次元のマルチチャネル光検知器を
干渉図計の検出部に用いる干渉計については、アプライ
ド・オプティックス、２３，２６９（１９８４年）第２
６９頁から第２７３頁（Ａｐｐｌ・０ρｔ・２３，２６
９（１９８４）ＰＰ２６９−２７３）　、およびアプラ
イド・スペクトロスコピー、４０，６９１（１９８６年
）第６９１頁から第６９５頁（Ａｐｐｌ・５ｐｅｃｆｒ
ｏｓｃ・４０，６９１　（１９８６）　Ｐ　Ｐ　６９１
−６９５）において論じられているように、ビームスプ
リッタ又は偏光プリズムによって被測定光束を２光束に
分割し、各光束が空間を伝播する間に各光束の断面内で
連続的に変化する光路差を発生させた後に結合させ、空
間上に形成された干渉図形を、一次元マルチチャネル検
知器で離散的にサンプリングするようになっていた。Regarding interferometers that use conventional one-dimensional or two-dimensional multichannel photodetectors as the detection section of interferometers, see Applied Optics, 23, 269 (1984), No. 2.
From page 69 to page 273 (Appl・0ρt・23,26
9 (1984) PP269-273), and Applied Spectroscopy, 40, 691 (1986) pp. 691-695 (Appl.
osc・40,691 (1986) P P 691
-695), a beam splitter or a polarizing prism splits the measured beam into two beams, and the optical path difference that continuously changes within the cross section of each beam as it propagates through space is calculated. After generation, they were combined and the interferograms formed in space were sampled discretely using a one-dimensional multichannel detector.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

上記従来技術では、干渉計を構成する光学素子の配置が
振動や外力によって変化を受けた場合、２光束の断面内
における光路差の変化が正規の状態からずれる点につい
て配慮されておらず、振動が干渉計に加わる場合、安定
な測定ができない問題があった。The above conventional technology does not take into account the fact that when the arrangement of the optical elements constituting the interferometer is changed due to vibration or external force, the change in the optical path difference in the cross section of the two light beams deviates from the normal state. When applied to the interferometer, there was a problem that stable measurements could not be made.

本発明の目的は、干渉計に振動が加わる環境下でも安定
に測定することのできる干渉計を提供することにある。An object of the present invention is to provide an interferometer that can perform stable measurements even in an environment where vibrations are applied to the interferometer.

〔問題点を解決するための手段〕[Means for solving problems]

上記目的は、被測定光束を複数の２光束の対に分割し、
各々を独立な固体閉路中を伝播させ、その間に各々の２
光束間に各２光束対毎に異なる光路差を生じさせること
によって達成される。The above purpose is to divide the light flux to be measured into a plurality of pairs of two light fluxes,
Each is propagated through an independent solid circuit, while each 2
This is achieved by creating a different optical path difference between the light beams for each pair of two light beams.

〔作用〕[Effect]

本発明の干渉計の構成を第１図に示す。被測定光源１を
出た被測定光束２はコリメーター３によって平行光束４
となり、光フアイバー束５に入射する。この光フアイバ
ー束５は、各々２本のファイバーから成るＮ対のファイ
バ一対６から成る。The configuration of the interferometer of the present invention is shown in FIG. The light beam 2 to be measured that exits the light source 1 to be measured is converted into a parallel light beam 4 by the collimator 3.
and enters the optical fiber bundle 5. The optical fiber bundle 5 consists of N pairs of fibers 6 each consisting of two fibers.

各ファイバ一対の一方のファイバー７はＮ対について全
て等しい光路長Ｑで、他方のファイバー８は６対で異な
り、ｎ番目の対については光路長がＱ＋　（ｎ−Ｎ、／
２）ＸΔＱ となっている。これにより、ｎ番目の対の２本のファイ
バー間には（ｎ−Ｎ／２）ＸΔＱだけの光路差があり、
ｎ番目とｎ　４１番目の対の間では光路差がΔＱだけ異
なる。６対の２本のファイバー７゜８から出た光は光結
合器９で再結合されて干渉を起こし、Ｎビットの絵素か
ら成る一次元マルチチャネル光検知器１ｏの対応する絵
素１１にて検出される。これにより一次元マルチチャネ
ル光検出器１ｏの出力として、被測定光束２によって生
じる干渉図形を光路差ΔＱ毎にサンプリングした信号が
得られる。One fiber 7 of each pair of fibers has the same optical path length Q for all N pairs, the other fiber 8 has different optical path lengths for 6 pairs, and the optical path length for the nth pair is Q+ (n-N, /
2) XΔQ. As a result, there is an optical path difference of (n-N/2)XΔQ between the two fibers of the n-th pair,
The optical path difference between the nth and n41st pairs differs by ΔQ. The light emitted from the six pairs of two fibers 7°8 is recombined by the optical coupler 9, causing interference, and is transmitted to the corresponding picture element 11 of the one-dimensional multichannel photodetector 1o consisting of N-bit picture elements. detected. As a result, a signal obtained by sampling the interference pattern generated by the measured light beam 2 for each optical path difference ΔQ is obtained as the output of the one-dimensional multichannel photodetector 1o.

この干渉計によれば、各ファイバ一対における光路差は
振動によって変化することが無いため、安定な測定を行
うことができる。According to this interferometer, since the optical path difference between each pair of fibers does not change due to vibration, stable measurements can be performed.

また、前記の光フアイバー束のかわりに、第２図に示す
先導波路を用いることもできる。これは半導体等の基板
１上に透明材料から成る先導波路２を前記光ファイバー
東同様にＮ本設ける。各先導波路は光２分岐部３を有し
、この部分で２本の先導波路に分れ、光再結合部４で再
び１本の先導波路となる。この２分岐した部分の２本の
先導波路の間の光路長差を前記光ファイバー束同様Ｎ本
毎に異なるようにし、光再結合後、同一基板上に形成し
たＮビットのフォトダイオード５にて検知する。この場
合にも、各ビット毎の光路差は振動によって変化するこ
とは無い。Furthermore, instead of the optical fiber bundle described above, a guiding waveguide shown in FIG. 2 can also be used. In this case, N leading waveguides 2 made of a transparent material are provided on a substrate 1 made of a semiconductor or the like, similar to the optical fiber east described above. Each leading waveguide has an optical two-branching section 3, where it splits into two leading waveways, and becomes one leading wavepath again at an optical recombining section 4. The optical path length difference between the two leading waveguides of this two-branched portion is made to be different for each N optical fiber bundle as in the above-mentioned optical fiber bundle, and after optical recombination, it is detected by an N-bit photodiode 5 formed on the same substrate. do. In this case as well, the optical path difference for each bit does not change due to vibration.

〔発明の効果〕〔Effect of the invention〕

本発明によれば、干渉計に振動が加わる環境下でも安定
に測定することのできる干渉計を提供できる効果がある
。According to the present invention, it is possible to provide an interferometer that can perform stable measurements even in an environment where vibrations are applied to the interferometer.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の光ファイバーを用いた干渉計の構成図
、第２図は基板上に形成した先導波路及びフォトダイオ
ードアレイの構造図である。 １・・・被測定光源、２・・・被測定光束、３・・・コ
リメータ、４・・・平行光束、５・・・光フアイバー束
、６・・・光フアイバ一対、７及び８・・・光ファイバ
ー、９・・・光結合器、１０・・・一次元マルチチャネ
ル光検出器、１１・・・前記光検出器の一絵素、１２・
・・基板、１３・・・先導波路、１４・・・光２分岐部
、１５・・・光再結合部、１６・・・フォトダイオード
。FIG. 1 is a block diagram of an interferometer using an optical fiber according to the present invention, and FIG. 2 is a structural diagram of a leading waveguide and a photodiode array formed on a substrate. DESCRIPTION OF SYMBOLS 1... Light source to be measured, 2... Light flux to be measured, 3... Collimator, 4... Parallel light flux, 5... Optical fiber bundle, 6... Pair of optical fibers, 7 and 8... - Optical fiber, 9... Optical coupler, 10... One-dimensional multi-channel photodetector, 11... One pixel of the photodetector, 12.
. . . Substrate, 13 . . . Guide wave path, 14 . . . 2-light branching section, 15 . . .

Claims (1)

【特許請求の範囲】 １、一次元または二次元のマルチチャネル光検出器を干
渉図形検出部にもつ干渉計において、被測定光束を複数
の２光束の対に分割し、分割された各光束を独立な閉路
中を伝播させ、その間に各々の２光束間に各２光束の対
毎で異なる光路差を生じさせ、然る後、各２光束を再び
結合して干渉を起こさせ、一次元または二次元のマルチ
チャネル光検出器の各絵素に導いて検出するようにした
ことを特徴とする干渉計。 ２、特許請求の範囲第１項において、複数に分割された
各２光束の伝播媒体として、光路長が互いに異なる一対
の光ファイバを用いることを特徴とする干渉計。 ３、特許請求の範囲第１項において、複数に分割された
各２光束の伝播媒体として、半導体等の基板上に形成し
た光路長が互いに異なる一対の光導波路を用いることを
特徴とする干渉計。 ４、特許請求の範囲第１項において、光導波路と同一基
板上に、マルチチャネル光検出器を形成させ、その各絵
素に光導波路を接続して検知することを特徴とする干渉
計。[Claims] In an interferometer having a one-dimensional or two-dimensional multi-channel photodetector in an interferogram detection section, a beam to be measured is divided into a plurality of pairs of two beams, and each divided beam is divided into two pairs. The light beams are propagated through independent closed paths, during which a different optical path difference is created for each pair of two light beams, and then the two light beams are combined again to cause interference, resulting in one-dimensional or An interferometer characterized by detecting by guiding each picture element of a two-dimensional multichannel photodetector. 2. An interferometer according to claim 1, characterized in that a pair of optical fibers having different optical path lengths are used as propagation media for each of the two divided beams. 3. An interferometer according to claim 1, characterized in that a pair of optical waveguides formed on a substrate such as a semiconductor and having different optical path lengths are used as propagation media for each of the two divided beams. . 4. An interferometer according to claim 1, characterized in that a multichannel photodetector is formed on the same substrate as the optical waveguide, and the optical waveguide is connected to each picture element of the multichannel photodetector for detection.