JPH03215710A - Optical fiber measuring instrument - Google Patents
Optical fiber measuring instrumentInfo
- Publication number
- JPH03215710A JPH03215710A JP833990A JP833990A JPH03215710A JP H03215710 A JPH03215710 A JP H03215710A JP 833990 A JP833990 A JP 833990A JP 833990 A JP833990 A JP 833990A JP H03215710 A JPH03215710 A JP H03215710A
- Authority
- JP
- Japan
- Prior art keywords
- polarization
- maintaining fiber
- light
- optical fiber
- polarized wave
- 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
Links
- 239000013307 optical fiber Substances 0.000 title claims description 13
- 239000000835 fiber Substances 0.000 claims abstract description 19
- 238000001514 detection method Methods 0.000 claims description 4
- 238000005259 measurement Methods 0.000 claims description 3
- 230000008878 coupling Effects 0.000 claims description 2
- 238000010168 coupling process Methods 0.000 claims description 2
- 238000005859 coupling reaction Methods 0.000 claims description 2
- 239000000284 extract Substances 0.000 claims 1
- 230000010287 polarization Effects 0.000 abstract description 16
- 238000010586 diagram Methods 0.000 description 5
- 238000005452 bending Methods 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 2
- 238000000253 optical time-domain reflectometry Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Landscapes
- Length Measuring Devices By Optical Means (AREA)
- Optical Transform (AREA)
Abstract
Description
【発明の詳細な説明】
く産業上の利用分野〉
本発明は光ファイバ応力付与型センサの測定装置に関し
、単一地点のみならず多数の地点の状況を検知するもの
であり、例えばバルブの開閉状態の検知、ケーブルの浸
水、落雷など、環境の検知に関するものである。[Detailed Description of the Invention] Industrial Application Fields The present invention relates to a measuring device for an optical fiber stress-applying sensor, which detects the situation not only at a single point but also at many points, such as the opening and closing of a valve. It is concerned with environmental sensing, such as condition sensing, cable flooding, lightning strikes, etc.
く従来の技術とその課題〉
従来、光ファイバ応力付与型センサとしては特開昭６３
−２６６３３３号に示されるような浸水検知センサ、及
び特開昭６０−１４１１２１号に示されるような落雷検
知センサがあった。Conventional technology and its problems> Conventionally, as an optical fiber stress applying sensor, Japanese Patent Application Laid-Open No. 63
There were a flood detection sensor as shown in Japanese Patent Application No. 266333, and a lightning detection sensor as shown in Japanese Patent Application Laid-open No. 141121/1983.
この覆の装置は検出する量に応じて光ファイバに曲げ，
側圧などの応力を加え、その結果生じろ光伝送損失をＯ
Ｔ Ｄ Ｒ （Ｏｐｔｉｃａｌ ＴｉｍｅＤｏｍａｉ
ｎ Ｒｅｆｌｅｅｔｏｍｅｔｒｙ＝光時間領域反射測定
法）により、光強度の段差として検出する構造となって
いる。しかしこの場合、第２図に示すように応力を加え
た部分から後に数十メートルの範囲にわたってデッドゾ
ーンが生じる。このデッドゾーンは後方散乱光を取り込
むタイミングより広いパルスを使用した場合に大きく生
じるが、たとえ取り込むタイミングより狭いパルスを使
用した場合でも応力を加えた場所で生じろ光導波モード
の乱れのため発生する。このため多数のセンサを接近し
て配置できないという問題があった。This device bends the optical fiber according to the amount to be detected.
By applying stress such as lateral pressure, the resulting optical transmission loss is
T D R (Optical Time Domai
The structure is such that it is detected as a step in the light intensity using Refleetometry (optical time domain reflectometry). However, in this case, as shown in FIG. 2, a dead zone occurs over a range of several tens of meters after the stressed part. This dead zone occurs largely when a pulse wider than the timing to capture the backscattered light is used, but even if a pulse narrower than the timing to capture the backscattered light is used, it still occurs at places where stress is applied. . For this reason, there was a problem in that a large number of sensors could not be placed close to each other.
本発明は、上述の問題に鑑み、光導波モードの乱れのた
めデッドゾーン内での多数のセンサ配置ができないとい
う支障を除き、センサの近接配置を可能とした光ファイ
バ測定装置の提供を目的とする。In view of the above-mentioned problems, an object of the present invention is to provide an optical fiber measuring device that allows sensors to be placed close to each other, eliminating the problem that a large number of sensors cannot be placed in a dead zone due to the disturbance of the optical waveguide mode. do.
く課題を解決するための手段〉
上述の目的を達成する本発明は、外界の状態変化に基づ
く応力の発生にて光の伝搬状態を変化させる悩波保持フ
ァイバと、この偏波保持ファイバに光学的に接続されて
上記伝搬状態変化の発生位置を検出する手段と、を備え
たことを特徴とする。Means for Solving the Problems> The present invention achieves the above-mentioned objects by providing a polarization-maintaining fiber that changes the propagation state of light by the generation of stress based on a change in the state of the outside world, and an optical fiber for this polarization-maintaining fiber. and means for detecting the position where the change in the propagation state occurs.
く作 用〉
検出すべき環境の変化に応して発生する光ファイバへの
曲げや側圧などの応力の検出に当って、偏波保持ファイ
バには直又する偏波（Ｘ，Ｙ偏波とする）のどちらか一
方のみの成分、例えばＸ偏波のみの光パルスを入射する
。この光パルスはＸ偏波を導波するが、偏波保持ファイ
バに曲げ，側圧などの応力の生じた部分では、ｘ，Ｙ偏
波間でエネルギ結合が生じ、光の一部はＹ偏波へ漏れろ
。そして、Ｙ偏波面で光ファイバの入射端側へ反射する
成分が生じる。応力の生じた部分が多数あるとき、それ
ぞれの地点で反射する成分が生じろことになら、この反
射成分を入射パルスをトリガとして光ファイバの入射端
側より時間波形で測定すると、ＯＴＤＲの原理と同様第
３図の様な応力付与位置と反射レベルが得られる。ここ
で、第３図に示すそれぞれの位置での波形はフレネル反
射状の波形であり、かなり鋭いので多数のセンサを設置
する際に問題となっていたデッドゾーンを小さくするの
に非常に有効である。また、センサの動作時に現れる光
強度の段差波形を測定する従来の方法に比べて、反射波
形は形状がスパイク状であり非常に特徴的で検出が容易
である。Function> When detecting stress such as bending or lateral pressure on an optical fiber that occurs in response to changes in the environment to be detected, a polarization-maintaining fiber has orthogonal polarization (X, Y polarization and A light pulse of only one of the components (for example, only the X-polarized wave) is input. This optical pulse guides the X-polarized wave, but at the part where the polarization-maintaining fiber is bent or subjected to stress such as lateral pressure, energy coupling occurs between the x- and Y-polarized waves, and a part of the light becomes the Y-polarized wave. Leak it. Then, a component is generated that is reflected toward the input end side of the optical fiber on the Y polarization plane. When there are many stressed parts, if a reflected component is generated at each point, if this reflected component is measured as a time waveform from the input end of the optical fiber using the incident pulse as a trigger, it will be possible to understand the principle of OTDR. Similarly, stress application positions and reflection levels as shown in FIG. 3 can be obtained. Here, the waveforms at each position shown in Figure 3 are Fresnel reflection waveforms, and are quite sharp, so it is very effective in reducing the dead zone that was a problem when installing a large number of sensors. be. Furthermore, compared to the conventional method of measuring the stepped waveform of light intensity that appears during sensor operation, the reflected waveform has a spike-like shape, which is very characteristic and easy to detect.
施 例〉 ここで、第１図を参照して本発明の実施例を説明する。Example An embodiment of the present invention will now be described with reference to FIG.
第１図において、１は光源、２は偏波ビームスプリツタ
であり、この偏波ピームスプリッタ２ぱ直交２偏波のう
ちの一方の偏波光のみを分離するものである。In FIG. 1, 1 is a light source, and 2 is a polarized beam splitter. This polarized beam splitter 2 separates only one of two orthogonal polarized waves.
応力付与センサとしての検知部としては、偏波保持ファ
イバ３が配置される。A polarization maintaining fiber 3 is arranged as a detection section as a stress applying sensor.
４は偏波ピームスプリッタ２からの反射光の受光器、５
はＣＰＵである。また、ＣＰＵ５の出力表示としてＣＲ
Ｔ６が備えられる。4 is a receiver for the reflected light from the polarization beam splitter 2; 5
is the CPU. Also, as the output display of CPU5, CR
T6 is provided.
かかる第１図の構成において、光源工から偏波ビームス
ブリッタ２を介してｘｌＩ波のみの光パルスを偏波保持
ファイバ３に入射する。In the configuration shown in FIG. 1, a light pulse of only xlI waves is input from a light source through a polarization beam splitter 2 into a polarization-maintaining fiber 3.
偏波保持ファイバ３に部分的に曲げを発生させろと、そ
の後方散乱光のうち他方の偏波であるＹｌｉ波成分のみ
の反射が生じ、これを偏波ビームスプリッタ２により分
離して受光器４にて受光する。ＣＰＵ５ではＸＭ波の入
射パルスをトリガとしてとらえ受光器４にてく実
得られたＹ偏波成分を得て、時間波形で測定し画面表示
を得る。乙の結果が例えば第３図の波形である。この場
合、第３図の如く鋭いパルス状に波形が得られた。When the polarization-maintaining fiber 3 is partially bent, only the other polarized Yli wave component of the backscattered light is reflected, which is separated by the polarization beam splitter 2 and transmitted to the light receiver 4. The light is received at. The CPU 5 takes the incident pulse of the XM wave as a trigger, sends it to the light receiver 4, obtains the actually obtained Y polarization component, measures it as a time waveform, and obtains a screen display. The result of B is the waveform shown in FIG. 3, for example. In this case, a sharp pulse-like waveform was obtained as shown in FIG.
第１図と同一測定系において、従来の光ファイバとＯＴ
ＤＲとによる曲げ付与間隔を接近させた波形との比較を
第４図に示している。In the same measurement system as in Figure 1, conventional optical fiber and OT
FIG. 4 shows a comparison with a waveform in which the bending interval is made closer to that of DR.
従来方法ではデッドゾーンとなったケースでも本例では
鋭いパルス波形が得られており、位置分解能が向上した
。Even in cases where the conventional method would result in a dead zone, in this example a sharp pulse waveform was obtained, and the positional resolution was improved.
上記実施例においては、偏波保持ファイバとして、応力
付与型のものを用いたが、これに限られるものではなく
、一般に知られている、いわゆる偏波保持ファイバであ
れば良い。In the above embodiments, a stress-applying type fiber is used as the polarization-maintaining fiber, but the present invention is not limited to this, and any generally known so-called polarization-maintaining fiber may be used.
又光源の種類によっては、偏波変動が大きいので、この
場合あらかじめ偏光子を通過させ、直ＮｓＩＩｆＡ光と
してから偏波保持ファイバに入射する方が望ましい。Furthermore, depending on the type of light source, polarization fluctuations may be large, so in this case, it is preferable to pass the light through a polarizer in advance to form direct NsIIfA light before inputting it into the polarization-maintaining fiber.
曲げを加える方向は、特に限定されるものではないが、
直交２偏波間の伝搬定数差が小さくなる方向に加えた場
合、高感度とすることが可能となる。The direction of bending is not particularly limited, but
If it is applied in a direction that reduces the difference in propagation constant between two orthogonal polarized waves, high sensitivity can be achieved.
く発明の効果〉
以上説明したように本発明によれば、偏波保持ファイバ
の直交二偏波を利用することにより、外力の検出を容易
にできかつデッドゾーンを短くしてセンサの近接配置が
可能となり、高精度の位置分解能をもつ測定装置を得ろ
ことができる。Effects of the Invention> As explained above, according to the present invention, by using two orthogonal polarized waves of a polarization-maintaining fiber, it is possible to easily detect an external force, shorten the dead zone, and allow sensors to be placed close to each other. This makes it possible to obtain a measuring device with highly accurate position resolution.
第１図は本発明の一実施例の簡略構成図、第２図は従来
例によるデッドゾーンの説明図、第３図は本発明の一実
施例の測定波形図、第４図は従来例と本発明の一例との
測定波形の比較説明図である。
図 中、
２は偏波ビームスプリツタ、
３は偏波保持ファイバ、
４は受光器、
５はＣＰＵである。
第
１
図
曲げ付与
距離Fig. 1 is a simplified configuration diagram of an embodiment of the present invention, Fig. 2 is an explanatory diagram of a dead zone according to a conventional example, Fig. 3 is a measured waveform diagram of an embodiment of the present invention, and Fig. 4 is a diagram of a conventional example. FIG. 3 is an explanatory diagram for comparing measurement waveforms with an example of the present invention. In the figure, 2 is a polarization beam splitter, 3 is a polarization maintaining fiber, 4 is a light receiver, and 5 is a CPU. Figure 1 Bending distance
Claims (2)
状態を変化させる偏波保持ファイバと、この偏波保持フ
ァイバに光学的に接続されて上記伝搬状態変化の発生位
置を検出する手段と、を備えた光ファイバ測定装置。(1) A polarization-maintaining fiber that changes the propagation state of light by the generation of stress based on changes in the state of the outside world, and a means that is optically connected to this polarization-maintaining fiber to detect the position at which the change in the propagation state occurs. An optical fiber measurement device equipped with and.
波のうちいずれか一方のみの偏波光を入射し、発生位置
の検出手段では応力の発生による直交二偏波間のエネル
ギ結合により生じる他方の偏波光を取り出すことを特徴
とする請求項（１）の光ファイバ測定装置。(2) Only one polarized light of two mutually orthogonal polarized waves is input into the polarization-maintaining fiber, and the generation position detection means detects the other polarized light generated by energy coupling between the two orthogonal polarized waves due to the generation of stress. 2. The optical fiber measuring device according to claim 1, wherein the optical fiber measuring device extracts polarized light.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP833990A JPH03215710A (en) | 1990-01-19 | 1990-01-19 | Optical fiber measuring instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP833990A JPH03215710A (en) | 1990-01-19 | 1990-01-19 | Optical fiber measuring instrument |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03215710A true JPH03215710A (en) | 1991-09-20 |
Family
ID=11690444
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP833990A Pending JPH03215710A (en) | 1990-01-19 | 1990-01-19 | Optical fiber measuring instrument |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03215710A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8159601B2 (en) | 2008-09-19 | 2012-04-17 | Pentax Ricoh Imaging Company, Ltd. | Sequential shooting controller |
-
1990
- 1990-01-19 JP JP833990A patent/JPH03215710A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8159601B2 (en) | 2008-09-19 | 2012-04-17 | Pentax Ricoh Imaging Company, Ltd. | Sequential shooting controller |
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