JPH02102425A - Optical path difference zero point detecting device and optical interference signal averaging processor using same - Google Patents
Optical path difference zero point detecting device and optical interference signal averaging processor using sameInfo
- Publication number
- JPH02102425A JPH02102425A JP25678288A JP25678288A JPH02102425A JP H02102425 A JPH02102425 A JP H02102425A JP 25678288 A JP25678288 A JP 25678288A JP 25678288 A JP25678288 A JP 25678288A JP H02102425 A JPH02102425 A JP H02102425A
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- light
- interference signal
- optical path
- path difference
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- 230000003287 optical effect Effects 0.000 title claims abstract description 90
- 238000012935 Averaging Methods 0.000 title claims abstract description 28
- 230000003595 spectral effect Effects 0.000 claims abstract description 4
- 238000001514 detection method Methods 0.000 claims description 23
- 238000012545 processing Methods 0.000 claims description 21
- 238000001228 spectrum Methods 0.000 description 26
- 238000010586 diagram Methods 0.000 description 7
- 238000005070 sampling Methods 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 4
- 229910052734 helium Inorganic materials 0.000 description 3
- 239000001307 helium Substances 0.000 description 3
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 3
- 238000000034 method Methods 0.000 description 2
- 235000019687 Lamb Nutrition 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
- 238000010408 sweeping Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
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Abstract
Description
【発明の詳細な説明】
「産業上の利用分野」
この発明は光スペクトラムアナライザのような測定器に
利用することができる光路差ゼロ点検出装置及びこの検
出装置を利用した光干渉信号平均化処理装置に関する。Detailed Description of the Invention "Field of Industrial Application" This invention relates to an optical path difference zero point detection device that can be used in a measuring instrument such as an optical spectrum analyzer, and an optical interference signal averaging process using this detection device. Regarding equipment.
「従来の技術」
第６図に従来の光路差ゼロ点検出装置を利用した光干渉
信号平均化処理装置の構成を示す。"Prior Art" FIG. 6 shows the configuration of an optical interference signal averaging processing device using a conventional optical path difference zero point detection device.
図中ＩＯは光干渉計を示す。この例ではマイケルソン干
渉計を利用した場合を示すが、他の形式の光干渉計を使
うこともできる。In the figure, IO indicates an optical interferometer. Although this example uses a Michelson interferometer, other types of optical interferometers can also be used.
マイケルソン光干渉計ｌＯはハーフミラ−１１と、固定
ミラー１２及び可動ミラー１３と、受光器１４．１５と
によって構成される。The Michelson optical interferometer 10 is composed of a half mirror 11, a fixed mirror 12, a movable mirror 13, and a light receiver 14.15.
ハーフミラ−１１には、外部から例えばヘリウムレーザ
のように狭スペクトル光を発射する基準光源２０の基準
光２１と、被測定光２２とを二つの光路ＡとＢに振り分
ける動作を受は持つ。The half mirror 11 has a receiver that distributes the reference light 21 from the reference light source 20 emitting narrow spectrum light from the outside, such as a helium laser, and the measured light 22 into two optical paths A and B.
つまり基準光２１に関してはハーフミラ−１１で反射し
て固定ミラー１２で折返されて受光器ｌ４に入る光路長
が固定された固定光路Ａと、ハーフミラ−１１を通過し
て可動ミラー１３で折返され受光器１４に入る光路長が
可動ミラー１３の動きに応じて変化する可変光路Ｂの二
つに振り分けられる。In other words, the reference light 21 is reflected by the half mirror 11, reflected by the fixed mirror 12, and then enters the receiver l4.The optical path A has a fixed optical path length, and the other is the fixed optical path A, which passes through the half mirror 11, is reflected by the movable mirror 13, and is received. The optical path length entering the device 14 is divided into two variable optical paths B whose length changes according to the movement of the movable mirror 13.
一方被測定光２２に関してはハーフミラ−１１で反射し
て固定ミラー１２で折返されて受光器１５に入る固定光
路Ａと、ハーフミラ−１１を通過して可動ミラー１３で
折返されハーフミラ−１１で反射して受光器１５に入射
する可変光路Ｂの二つの光路に振り分けられる。On the other hand, the light to be measured 22 is reflected by the half mirror 11, reflected by the fixed mirror 12, and enters the light receiver 15, and then passes through the half mirror 11, reflected by the movable mirror 13, and reflected by the half mirror 11. The light is then distributed into two optical paths, a variable optical path B, which enters the light receiver 15.
これら二つの光路ＡとＢを通過した基準光２１と被測定
光２２は最終的に受光器１４と１５に入射する部分で合
波される。可動ミラー１３は矢印Ｘ方向にほぼ一定速度
で移動され、光路ＡとＢに光路差を与え、更にこの光路
差を変化させる。The reference light 21 and the measured light 22 that have passed through these two optical paths A and B are finally combined at the portions where they enter the light receivers 14 and 15. The movable mirror 13 is moved at a substantially constant speed in the direction of arrow X, giving an optical path difference between optical paths A and B, and further changing this optical path difference.
この光路差の変化によって基準光２１と被測定光２２は
各自が互に干渉を起し、可動ミラー１３の移動速度と、
光の波長に同期した周期で明暗が繰返される。この明暗
の変化を受光器１４と１５から電気信号として取出し干
渉信号を得る。Due to this change in optical path difference, the reference light 21 and the measured light 22 interfere with each other, and the moving speed of the movable mirror 13 and
Light and darkness are repeated in a cycle synchronized with the wavelength of light. This change in brightness is extracted as an electrical signal from the light receivers 14 and 15 to obtain an interference signal.
可動ミラー１３はＸ方向の最大偏倚点に達すると急激に
元の位置に戻され、再び矢印Ｘ方向に定速度で移動し、
これを繰返す。従って受光器１４と１５から基準光２１
の干渉信号と被測定光２２の干渉信号を繰返し得ること
ができる。When the movable mirror 13 reaches the maximum deflection point in the X direction, it is suddenly returned to its original position, and moves again at a constant speed in the direction of the arrow X.
Repeat this. Therefore, from the light receivers 14 and 15, the reference light 21
The interference signal of the measured light 22 and the interference signal of the measured light 22 can be obtained repeatedly.
受光器１５から得られる被測定光２２の干渉信号はＡＤ
変換器３０に与えられ、ＡＤ変換器３０でＡＤ変換され
る。ＡＤ変換器３０のＡＤ変換動作は基準光２１の干渉
信号を逓倍回路３１でｎ逓倍してサンプリングクロック
を生成し、このサンプリングクロックを利用してＡＤ変
換動作を行なう。The interference signal of the measured light 22 obtained from the light receiver 15 is AD
The signal is given to the converter 30 and AD converted by the AD converter 30. In the AD conversion operation of the AD converter 30, the interference signal of the reference light 21 is multiplied by n in the multiplier circuit 31 to generate a sampling clock, and this sampling clock is used to perform the AD conversion operation.
つまり基準光源２０はＡＤ変換器３０のサンプリングパ
ルスを生成するために設けられている。That is, the reference light source 20 is provided to generate sampling pulses for the AD converter 30.
従って逓倍回路３１に入力される干渉信号の振幅は可動
ミラー１３の移動に関係なく一定振幅を維持した方が好
ましい。Therefore, it is preferable that the amplitude of the interference signal input to the multiplier circuit 31 is maintained constant regardless of the movement of the movable mirror 13.
このため基準光源２０としては単一スペクトラムに近い
狭スペクトラム特性を持つ光が利用される。つまり挟ス
ベク］・ラム特性を持つ光の干渉信号は、第７図に示す
ように可動ミラー１３の位置に関係なく一定のレベルで
繰返される。Therefore, as the reference light source 20, light having narrow spectrum characteristics close to a single spectrum is used. In other words, the optical interference signal having the narrow Svek and Lamb characteristics is repeated at a constant level regardless of the position of the movable mirror 13, as shown in FIG.
これに対して広スペクトラム特性を持つ光の干渉信号は
第８図に示すように可動ミラー１３が光路差ゼロの点ｌ
。を通過するとき最大振幅となる変化を呈する。On the other hand, as shown in FIG. 8, the interference signal of light with wide spectrum characteristics is generated at the point l where the movable mirror 13 has zero optical path difference.
. It exhibits a change with maximum amplitude when passing through .
従って基準光源２０としてはヘリウムレーザのような挟
スペクトラム特性の光を発生する光源が用いられ、振幅
変動の少ない干渉信号を生成して安定なサンプリングパ
ルスを得るようにしている。Therefore, a light source that generates light with narrow spectrum characteristics, such as a helium laser, is used as the reference light source 20, and an interference signal with little amplitude fluctuation is generated to obtain a stable sampling pulse.
一方ｎ逓倍回路３Ｉで生成されたサンプリングクロック
によって被測定光２２の干渉信号をＡＤ変換し、このＡ
Ｄ変換した可動ミラー１３の各位置におけるサンプルデ
ータを例えばＦＦＴのような周波数分析装置に与え、周
波数分析することにより被測定光２２のスペクトラムを
表示することができる。On the other hand, the interference signal of the light to be measured 22 is AD converted by the sampling clock generated by the n multiplier circuit 3I.
The spectrum of the light to be measured 22 can be displayed by applying the D-converted sample data at each position of the movable mirror 13 to a frequency analyzer such as FFT and performing frequency analysis.
ところで被測定光２２は弱い光の場合が多い。Incidentally, the light to be measured 22 is often weak light.
このため可動ミラー１３が一回掃引されて得られた被測
定光２２の干渉信号を周波数分析してもＳＮ比が悪く、
精度の高い周波数分析結果を得ることはむずかしい。For this reason, even if the interference signal of the measured light 22 obtained by sweeping the movable mirror 13 once is analyzed by frequency, the S/N ratio is poor.
It is difficult to obtain highly accurate frequency analysis results.
このため従来よりＡＤ変換器３０の後に加算平均化処理
装置３３を設け、この加算平均化処理装置３３でＡＤ変
換した各サンプル値を可動ミラー１３の掃引毎に加算し
て平均化処理し、この加算平均化処理によってＳＮ比を
向上させ精度の高い周波数分析結果を得るようにしてい
る。For this reason, conventionally, an averaging processing device 33 is provided after the AD converter 30, and each sample value AD-converted by the averaging processing device 33 is added and averaged every time the movable mirror 13 sweeps. The averaging process improves the SN ratio and obtains highly accurate frequency analysis results.
加算平均化処理装置３３でＡＤ変換した各サンプル値を
加算する場合に各掃引周期毎に可動ミラー１３のアドレ
スが一致したサンプルを加算しなければならない。When adding the sample values AD-converted by the averaging processing device 33, samples whose addresses on the movable mirror 13 match must be added every sweep period.
このため従来より可動ミラー１３が光路ＡとＢの光路差
がゼロの点を通過するとき広スペクトラム特性を持つ光
の干渉信号の振幅が最大となる現象を利用して光路差ゼ
ロのアドレスを規定し、このアドレスを基準に各ＡＤ変
換したサンプルデータのアドレスを規定して掃引周期毎
に同一アドレスのサンプルデータを加算してＳＮ比のよ
り干渉信号が得られるようにしている。For this reason, conventionally, the address of zero optical path difference is defined by utilizing the phenomenon that when the movable mirror 13 passes through a point where the optical path difference between optical paths A and B is zero, the amplitude of the interference signal of light having wide spectrum characteristics becomes maximum. Then, the address of each AD-converted sample data is defined based on this address, and the sample data of the same address is added every sweep period, so that an interference signal with a higher S/N ratio can be obtained.
３２はこのために設けられた最大値検出回路を示し、こ
の最大値検出回路３２によって比測定器の干渉信号の最
大値を検出し、この最大値が得られるＡＤ変換値のアド
レスを基準にして各ＡＤ変換データのアドレスを規定す
るようにしている。Reference numeral 32 indicates a maximum value detection circuit provided for this purpose, and this maximum value detection circuit 32 detects the maximum value of the interference signal of the ratio measuring device, and based on the address of the AD conversion value from which this maximum value is obtained, The address of each AD conversion data is defined.
「発明が解決しようとする課題」
ところで光の干渉は先にも説明したように挟スペクトラ
ム特性の場合は光路差がゼロの点でも振幅があまり変化
しない特質を持つ。また広スペクトラム特性の光であっ
ても光の強度が弱い場合はＳＮ比が悪いため光路差ゼロ
の点で振幅が増加したとしても光路差ゼロの点を正確に
特定することはむずかしい。``Problems to be Solved by the Invention'' By the way, as explained earlier, when light interference has narrow spectrum characteristics, the amplitude does not change much even at a point where the optical path difference is zero. Furthermore, even if the light has wide spectrum characteristics, if the intensity of the light is low, the signal-to-noise ratio is poor, so even if the amplitude increases at the point where the optical path difference is zero, it is difficult to accurately identify the point where the optical path difference is zero.
被測定光２２は弱い光の場合もあれば、挟スペクトル特
性の光の場合があるため、どのような場合にも光路差ゼ
ロの点を適確に検出することができない欠点がある。Since the light to be measured 22 may be weak light or light with narrow spectral characteristics, there is a drawback that the point of zero optical path difference cannot be accurately detected in any case.
この発明の目的は被測定光が弱い光の場合でも、また挟
スペクトラム特性を持つ場合でも正確に光路差がゼロの
点を検出することができる光路差ゼロ検出装置と、この
光路差ゼロ検出装置を用いて正しい平均化処理を行なっ
てＳＮ比のよい干渉信号を出力する光干渉信号平均化処
理装置を提供しようとするものである。The purpose of the present invention is to provide a zero optical path difference detection device that can accurately detect the point at which the optical path difference is zero even when the light to be measured is weak or has narrow spectrum characteristics, and this zero optical path difference detection device. It is an object of the present invention to provide an optical interference signal averaging processing device that performs correct averaging processing using the following and outputs an interference signal with a good signal-to-noise ratio.
「課題を解決するための手段」
この出願の第１発明では広スペクトラム光を発光する補
助光源を設け、この補助光源で発光する広スペクトラム
光を基準光又は比測定光に合波して二つの光路を通過さ
せ、補助光の干渉信号を得ると共に、この補助光干渉信
号を最大値検出回路に与え、補助光干渉信号の振幅最大
点を光路差ゼロの点として検出するようにして光路差ゼ
ロ点検出装置を構成したものである。"Means for Solving the Problem" In the first invention of this application, an auxiliary light source that emits a wide spectrum light is provided, and the wide spectrum light emitted by the auxiliary light source is combined with a reference light or a ratio measurement light to generate two The auxiliary light interference signal is passed through the optical path to obtain the auxiliary light interference signal, and this auxiliary light interference signal is fed to the maximum value detection circuit, and the maximum amplitude point of the auxiliary light interference signal is detected as the point of zero optical path difference, so that the optical path difference is zero. This constitutes a point detection device.
またこの出願の第２発明ではこの光路差ゼロ点検出装置
によって検出した光路差ゼロのアドレスを基準に各ＡＤ
変換データのアドレスを規定し、可動ミラーの掃引毎に
同一アドレスのＡＤ変換データを加算し、平均化処理す
ることができる光スペクトル平均化処理装置を構成した
ものである。Further, in the second invention of this application, each AD is
This is an optical spectrum averaging processing device that can define the address of converted data, add AD converted data of the same address every time the movable mirror sweeps, and perform averaging processing.
「作 用」
この出願の第１発明によれば広スペクトル特性を持つ補
助光を光干渉計に与えて干渉させ、その干渉信号を得て
この干渉信号を最大値検出回路に与え、最大振幅点を検
出するようにしたから光路差ゼロの点を正しく検出する
ことができる。"Function" According to the first invention of this application, an auxiliary light having a wide spectrum characteristic is applied to an optical interferometer to cause interference, an interference signal is obtained, and this interference signal is applied to a maximum value detection circuit to detect the maximum amplitude point. Since the point where the optical path difference is zero can be detected correctly.
つまり広スペクトル特性を持つ光は光路差ゼロの点で顕
著に振幅が最大となる現象を呈し、更に補助光源から発
光させるため光の強度は必要なレベルに合致させること
ができる。In other words, light with broad spectrum characteristics exhibits a phenomenon in which the amplitude is significantly maximum at the point where the optical path difference is zero, and furthermore, since the light is emitted from the auxiliary light source, the intensity of the light can be matched to the required level.
よって被測定光の強度が弱くても、また挟スペクトル特
性を持つ光であっても、常に正しく光路差ゼロの点の可
動ミラー１３のアドレスを特定することができる。Therefore, even if the intensity of the light to be measured is weak or the light has narrow spectral characteristics, the address of the movable mirror 13 at the point where the optical path difference is zero can always be correctly specified.
この結果この出願の第２発明によれば可動ミラー１３の
掃引毎に得られるＡＤ変換されたサンプルデータを可動
ミラー１３の掃引位置に正確に対応付けすることができ
る。よって正しい加算平均処理を行なうことができるか
らＳＮ比のよい加算平均処理した干渉信号を出力するこ
とができ、精度の高い光スペクトラムを表示する光スペ
クトラムアナライザ等を提供することができる。As a result, according to the second invention of this application, the AD-converted sample data obtained every time the movable mirror 13 is swept can be accurately associated with the sweep position of the movable mirror 13. Therefore, since correct averaging processing can be performed, it is possible to output an interference signal subjected to averaging processing with a good S/N ratio, and it is possible to provide an optical spectrum analyzer or the like that displays a highly accurate optical spectrum.
「実施例」 第１図にこの発明の一実施例を示す。"Example" FIG. 1 shows an embodiment of the present invention.
第１図において、１０は光干渉計、２０は基準光源、３
０はＡＤ変換器、３１はｎ逓倍器、３３は加算平均化処
理装置を示す点は従来の構造と同じで・ある。In FIG. 1, 10 is an optical interferometer, 20 is a reference light source, and 3
The structure is the same as the conventional structure in that 0 indicates an AD converter, 31 indicates an n-multiplier, and 33 indicates an averaging processing device.
この出願の第１の発明では補助光源２３を設け、この補
助光源２３と合波器２５及び最大値検出回路３２とによ
って光路差ゼロ検出装置４０を構成した点を特徴とする
ものである。The first invention of this application is characterized in that an auxiliary light source 23 is provided, and a zero optical path difference detection device 40 is configured by this auxiliary light source 23, a multiplexer 25, and a maximum value detection circuit 32.
基準光源２０から照射する基準光２１は従来と同じ挟ス
ペクトル光とされ、補助光源２３から照射する補助光２
４は広スペクトル光とされる。このため基準光源２０は
例えばヘリウムレーザを用いることができ、これに対し
補助光源としては白色光源として例えばハロゲンランプ
或はＬＥＤ等を用いる。The reference light 21 emitted from the reference light source 20 is the same narrow spectrum light as in the past, and the auxiliary light 2 emitted from the auxiliary light source 23
4 is considered to be broad spectrum light. For this purpose, the reference light source 20 can be, for example, a helium laser, while the auxiliary light source is a white light source such as a halogen lamp or an LED.
この実施例では補助光源２３で発光させた補助光２４を
基準光２１が通る光路に与えるように構成した場合を示
す。このために基準光２１と補助光２４は合波器２５で
合波され固定ミラー２６で反射されて光干渉計１０に入
力する。This embodiment shows a case in which the auxiliary light 24 emitted by the auxiliary light source 23 is applied to the optical path along which the reference light 21 passes. For this purpose, the reference light 21 and the auxiliary light 24 are combined by a multiplexer 25, reflected by a fixed mirror 26, and input to the optical interferometer 10.
光干渉計１０ではハーフミラ−１１によって基準光２１
と補助光２４を合波した光を固定光路Ａと可変光路Ｂに
振り分けると共に被測定光２２も固定光路Ａ及び可変光
路Ｂに与え、光路差の変化によって各光を干渉させ受光
器１４から基準光２１と補助光２４との合波光の干渉信
号を得る。また受光器１５からは被測定光２２の干渉信
号を得る。In the optical interferometer 10, a reference light 21 is generated by a half mirror 11.
The light obtained by combining the and auxiliary light 24 is distributed to a fixed optical path A and a variable optical path B, and the light to be measured 22 is also applied to a fixed optical path A and a variable optical path B, and each light is caused to interfere with each other by changing the optical path difference, so that the reference light is transmitted from the light receiver 14. An interference signal of the combined light of the light 21 and the auxiliary light 24 is obtained. Further, an interference signal of the light to be measured 22 is obtained from the light receiver 15 .
基準光２１と補助光２４のスペクトラムを第２図に示す
ように基準光２１のスペクトルをＡ、補助光２４のスペ
クトルをＢのように選定することにより、受光器１４か
ら出力される干渉信号は第３図に示すような波形となる
。By selecting the spectrum of the reference light 21 and the auxiliary light 24 as A and B as shown in FIG. The waveform becomes as shown in FIG.
受光器１４から出力される光干渉信号はｎ逓倍器３１と
、最大値検出回路３２に与えられる。光干渉信号は第３
図に示すように基準光２１の波長をλとしたとき、その
λのλ／２を周期とする基準光２１の干渉信号が振幅変
調を受け、可動ミラー１３の移動位置が光路差ゼロ点を
通過する際に振幅が最大となる。The optical interference signal output from the light receiver 14 is given to an n multiplier 31 and a maximum value detection circuit 32. The optical interference signal is the third
As shown in the figure, when the wavelength of the reference light 21 is λ, the interference signal of the reference light 21 with a period of λ/2 of λ undergoes amplitude modulation, and the moving position of the movable mirror 13 reaches the zero optical path difference point. The amplitude is maximum when passing through.
最大値検出回路３２はこの振幅変調を受けた光干渉信号
の最大振幅Ｐ０が得られる可動ミラー１３のアドレス！
。を検出し、この最大振幅Ｐ０を与える可動ミラー１３
のアドレスＸ、を加算平均化処理装置３３に与える。The maximum value detection circuit 32 determines the address of the movable mirror 13 from which the maximum amplitude P0 of the optical interference signal subjected to this amplitude modulation is obtained!
. A movable mirror 13 detects this and gives this maximum amplitude P0.
address X, is given to the averaging processing device 33.
加算平均化処理装置３３は最大値検出回路３２から与え
られる光路差ゼロを与えるアドレスｉ。The averaging processing device 33 receives the address i given from the maximum value detection circuit 32 and gives zero optical path difference.
を基準アドレスとして定め、ＡＤ変換器３０から与えら
、れる各サンプルデータを加算し平均化処理する。尚こ
の加算平均化処理装置は各サンプルを加算して記憶する
メモリを含むマイクロコンピュータによって構成される
。is determined as a reference address, and each sample data given from the AD converter 30 is added and averaged. Note that this averaging processing device is constituted by a microcomputer including a memory for adding and storing each sample.
またｎ逓倍回路３１は光干渉信号のキャリヤ成分をｎ逓
倍し、ＡＤ変換器３０にサンプリングクロックとして与
えている。Further, the n-multiplying circuit 31 multiplies the carrier component of the optical interference signal by n and provides it to the AD converter 30 as a sampling clock.
「変形実施例」
第４図はこの発明の変形実施例を示す。この例では被測
定光２２に対して補助光源２３から補助光２４を合波器
２５で合波し、被測定光２２と補助光２４の合波光を固
定ミラー１２と可動ミラー１３によって形成される二つ
の光路Ａ、Ｂを通して受光器１５に入射するように構成
した場合を示す。"Modified Embodiment" FIG. 4 shows a modified embodiment of the present invention. In this example, the light to be measured 22 is combined with the auxiliary light 24 from the auxiliary light source 23 by the multiplexer 25, and the combined light of the light to be measured 22 and the auxiliary light 24 is formed by the fixed mirror 12 and the movable mirror 13. A case is shown in which the light is configured to enter the light receiver 15 through two optical paths A and B.
尚基準光源２０から照射される基準光２１はこの例では
単独で二つの光路を通って受光器１４に入射し、ｎ逓倍
器３１でｎ逓倍してＡＤ変換器３１のサンプリングクロ
ックとして利用される。In this example, the reference light 21 emitted from the reference light source 20 enters the light receiver 14 through two optical paths alone, is multiplied by n by an n multiplier 31, and is used as a sampling clock for the AD converter 31. .
受光器１５の出力には被測定光２２と補助光２４の干渉
光信号が取出される。この干渉光信号はＡＤ変換器３０
でＡＤ変換され、そのＡＤ変換出力を第５図に符号りを
付して示す特性を持つディジタルローパスフィルタ３４
に与え、ディジタルローパスフィルタ３４で被測定光の
成分を分離して取出し、加算平均化処理装置３３に与え
る。An interference light signal of the light to be measured 22 and the auxiliary light 24 is extracted from the output of the light receiver 15 . This interference optical signal is sent to the AD converter 30
A digital low-pass filter 34 which is AD-converted and whose AD-converted output is shown in FIG.
The components of the light to be measured are separated and extracted by the digital low-pass filter 34 and are provided to the averaging processing device 33 .
これと共にＡＤ変換器３０の出力を最大値検出回路３２
に与え、主に補助光２４の光路差ゼロ点における最大値
を検出する。At the same time, the output of the AD converter 30 is detected by the maximum value detection circuit 32.
The maximum value of the auxiliary light 24 at the zero optical path difference point is mainly detected.
このようにこの実施例でも光路差ゼロを検出する干渉信
号を広スペクトラム特性を持つ補助光によって生成する
から常に光の強度は充分な強度をもって一定に与えられ
、然も光路差ゼロ点における振幅変化も大きく得られる
から光路差ゼロの点を正確に求めることができる。In this way, also in this embodiment, since the interference signal for detecting zero optical path difference is generated by the auxiliary light having wide spectrum characteristics, the light intensity is always given at a constant and sufficient intensity, and the amplitude change at the zero optical path difference point is constant. Since a large value can be obtained, the point at which the optical path difference is zero can be accurately determined.
この結果加算平均化処理装置３３における加算平均化処
理も各アドレス毎に正しく行なわれるからＳＮ比のよい
平均化処理信号を得ることができる。As a result, since the averaging processing in the averaging processing device 33 is performed correctly for each address, it is possible to obtain an averaging processed signal with a good S/N ratio.
「発明の効果」
以上説明したようにこの出願の第１発明によれば広スペ
クトラム特性を持つ補助光を基準光又は被測定光に合波
してその干渉光信号で最大値検出を行なう構成としたか
ら、被測定光２２のレベルに左右されることなく、また
被測定光２２が挟スペクトラム特性であっても光路差ゼ
ロの点を正確に検出することができる光路差ゼロ点検出
装置を提供することができる。"Effects of the Invention" As explained above, according to the first invention of this application, the auxiliary light having wide spectrum characteristics is combined with the reference light or the measured light and the maximum value is detected using the interference light signal. Therefore, we provide an optical path difference zero point detection device that can accurately detect the point of zero optical path difference, regardless of the level of the measured light 22, and even if the measured light 22 has narrow spectrum characteristics. can do.
またこの出願の第２発明によれば光路差ゼロ点検出装置
を使うことによって加算平均化処理装置３３の加算平均
化処理が正確な基準アドレスを基に処理するから平均化
出力の精度が向上し、質のよいスペクトラム解析結果を
得ることができる。Further, according to the second invention of this application, by using the optical path difference zero point detection device, the averaging processing of the averaging processing device 33 is performed based on an accurate reference address, so that the accuracy of the averaged output is improved. , it is possible to obtain high-quality spectrum analysis results.
第１図はこの発明の一実施例を示すブロック図、第２図
はこの実施例に用いた基準光源と補助光源から照射され
る基準光と補助光のスペクトラムの一例を示すグラフ、
第３図は第１図の実施例で得られる補助光と基準光との
合波光の光路差ゼロ付近の光干渉信号の様子を説明する
ための波形図、第４図はこの発明の変形実施例を説明す
るためのブロック図、第５図はこの変形実施例に用いた
補助光と被測定光のスペクトラムの関係を説明するため
のグラフ、第６図は従来の技術を説明するためのブロッ
ク図、第７図は基準光源から発光される挟スペクトラム
特性を持つ光の干渉の様子を説明するための波形図、第
８図は広スペクトラム特性を持つ光の干渉の様子を説明
するための波形図である。
１０・・・光干渉計、２０・・・基準光源、２２・・・
被測定光、３０・・・ＡＤ変換器、３１・・・ｎ逓倍器
、３２・・・最大値検出回路、３３・・・加算平均化処
理装置、４０・・・光路差ゼロ点検出装置。FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a graph showing an example of the spectrum of the reference light and auxiliary light emitted from the reference light source and auxiliary light source used in this embodiment.
FIG. 3 is a waveform diagram for explaining the state of the optical interference signal near zero optical path difference of the combined light of the auxiliary light and the reference light obtained in the embodiment of FIG. 1, and FIG. 4 is a modified embodiment of the present invention. A block diagram for explaining an example, FIG. 5 is a graph for explaining the relationship between the spectra of the auxiliary light and the measured light used in this modified example, and FIG. 6 is a block diagram for explaining the conventional technique. Figure 7 is a waveform diagram to explain the interference of light with narrow spectrum characteristics emitted from the reference light source, and Figure 8 is a waveform diagram to explain the interference of light with wide spectrum characteristics. It is a diagram. 10... Optical interferometer, 20... Reference light source, 22...
Light to be measured, 30... AD converter, 31... n multiplier, 32... maximum value detection circuit, 33... averaging processing device, 40... optical path difference zero point detection device.
Claims (2)
光器と、 Ｃ、広いスペクトル分布を持つ補助光源と、 Ｄ、この補助光源と入力光又は基準光とを合波する合波
器と、 Ｅ、補助光を含む光干渉信号の最大値点を検出する最大
値検出回路と、 を具備して成る光路差ゼロ点検出装置。(1) A. An optical interferometer that can sweep the optical path difference; B. An optical receiver that converts the interference output light of this optical interferometer into an electrical signal; C. An auxiliary light source with a wide spectral distribution; D. , a multiplexer that combines the auxiliary light source and the input light or the reference light; and E, a maximum value detection circuit that detects the maximum point of the optical interference signal including the auxiliary light. Point detection device.
渉信号の最大値点を基準アドレスとして光干渉信号のＡ
Ｄ変換値を加算平均する加算平均化回路を具備して成る
光干渉信号平均化処理装置。(2) A of the optical interference signal using the maximum value point of the optical interference signal detected by the optical path difference zero point detection device as a reference address.
An optical interference signal averaging processing device comprising an averaging circuit that adds and averages D-converted values.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63256782A JP2889248B2 (en) | 1988-10-11 | 1988-10-11 | Optical interferometer for optical spectrum analyzer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63256782A JP2889248B2 (en) | 1988-10-11 | 1988-10-11 | Optical interferometer for optical spectrum analyzer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02102425A true JPH02102425A (en) | 1990-04-16 |
| JP2889248B2 JP2889248B2 (en) | 1999-05-10 |
Family
ID=17297373
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63256782A Expired - Fee Related JP2889248B2 (en) | 1988-10-11 | 1988-10-11 | Optical interferometer for optical spectrum analyzer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2889248B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1019774A (en) * | 1996-07-09 | 1998-01-23 | Yokogawa Electric Corp | Near infrared spectroscope |
| JP2013245981A (en) * | 2012-05-24 | 2013-12-09 | Konica Minolta Inc | Fourier transform spectrometer, fourier transform spectroscopy and attachment for fourier transform spectrometer |
| JP2015175678A (en) * | 2014-03-14 | 2015-10-05 | 株式会社日立エルジーデータストレージ | Optical tomographic observation device |
| JP2019194550A (en) * | 2018-05-02 | 2019-11-07 | 株式会社島津製作所 | Fourier transform type spectrophotometer |
| US10663347B2 (en) | 2017-10-25 | 2020-05-26 | Yokogawa Electric Corporation | Optical measurement apparatus and recording medium |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5821527A (en) * | 1981-07-31 | 1983-02-08 | Shimadzu Corp | Fourier converting type infrared spectrophotometer |
| JPS61500509A (en) * | 1983-11-28 | 1986-03-20 | マイダク・コ−ポレ−ション | Apparatus and method for photoluminescence analysis |
| JPS6238324A (en) * | 1985-08-12 | 1987-02-19 | Shimadzu Corp | Fourier transform type spectrophotometer |
| JPS633230A (en) * | 1986-06-23 | 1988-01-08 | Advantest Corp | Optical digital spectrum analyzer |
-
1988
- 1988-10-11 JP JP63256782A patent/JP2889248B2/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5821527A (en) * | 1981-07-31 | 1983-02-08 | Shimadzu Corp | Fourier converting type infrared spectrophotometer |
| JPS61500509A (en) * | 1983-11-28 | 1986-03-20 | マイダク・コ−ポレ−ション | Apparatus and method for photoluminescence analysis |
| JPS6238324A (en) * | 1985-08-12 | 1987-02-19 | Shimadzu Corp | Fourier transform type spectrophotometer |
| JPS633230A (en) * | 1986-06-23 | 1988-01-08 | Advantest Corp | Optical digital spectrum analyzer |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1019774A (en) * | 1996-07-09 | 1998-01-23 | Yokogawa Electric Corp | Near infrared spectroscope |
| JP2013245981A (en) * | 2012-05-24 | 2013-12-09 | Konica Minolta Inc | Fourier transform spectrometer, fourier transform spectroscopy and attachment for fourier transform spectrometer |
| JP2015175678A (en) * | 2014-03-14 | 2015-10-05 | 株式会社日立エルジーデータストレージ | Optical tomographic observation device |
| US10663347B2 (en) | 2017-10-25 | 2020-05-26 | Yokogawa Electric Corporation | Optical measurement apparatus and recording medium |
| JP2019194550A (en) * | 2018-05-02 | 2019-11-07 | 株式会社島津製作所 | Fourier transform type spectrophotometer |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2889248B2 (en) | 1999-05-10 |
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