JPH07243902A - Optical fiber passive acoustic sensor - Google Patents
Optical fiber passive acoustic sensorInfo
- Publication number
- JPH07243902A JPH07243902A JP6457394A JP6457394A JPH07243902A JP H07243902 A JPH07243902 A JP H07243902A JP 6457394 A JP6457394 A JP 6457394A JP 6457394 A JP6457394 A JP 6457394A JP H07243902 A JPH07243902 A JP H07243902A
- Authority
- JP
- Japan
- Prior art keywords
- laser light
- acoustic sensor
- optical fiber
- interference
- sensor
- 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.)
- Withdrawn
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、水中音響測定装置のセ
ンサー部に好適な光ファイバーパッシブ音響センサーに
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber passive acoustic sensor suitable for a sensor part of an underwater acoustic measuring device.
【０００２】[0002]
【従来の技術】従来の水中音響センサーは、図６側面図
に示すように、音圧センサーとしてはセラミックセンサ
ー等の素子を採用し、この音圧センサー自体が直接、水
中音響測定装置の電気回路の一部となっている。2. Description of the Related Art A conventional underwater acoustic sensor employs an element such as a ceramic sensor as a sound pressure sensor, as shown in the side view of FIG. 6, and the sound pressure sensor itself is directly connected to an electric circuit of an underwater acoustic measuring device. Has become a part of.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、従来の
この種の水中音響測定装置においては、下記のような問
題がある。 （１）音圧センサー自体が電気回路系の一部であり、こ
れらを直接水中に曝す必要があるので、腐食対策を十分
に留意しなければならない。 （２）また、伝送損失及び電気雑音による測定誤差が生
じやすい。 （３）このような関係で、船上から行う深海部の測定に
は不向きである。However, the conventional underwater acoustic measuring device of this type has the following problems. (1) Since the sound pressure sensor itself is a part of the electric circuit system and these need to be directly exposed to water, it is necessary to pay sufficient attention to measures against corrosion. (2) Further, a measurement error easily occurs due to transmission loss and electric noise. (3) Due to this kind of relationship, it is not suitable for deep-sea measurements from the ship.
【０００４】本発明はこのような事情に鑑みて提案され
たもので、Ｓ／Ｎ比が優れ、高感度かつ高精度で船上か
らの深海部測定にも好適な高性能かつ長寿命の光ファイ
バーパッシブ音響センサーを提供することを目的とす
る。The present invention has been proposed in view of the above circumstances, and has a high performance and a long life optical fiber passive, which has an excellent S / N ratio, is highly sensitive and highly accurate, and is suitable for deep-sea measurement from a ship. The purpose is to provide an acoustic sensor.
【０００５】[0005]
【課題を解決するための手段】そのために請求項１の発
明は、レーザー光源から出力するレーザー光を参照レー
ザー光と変調用レーザー光とに２分する分光手段と、単
一モード光ファイバーをコイル状に巻回してなる音響セ
ンサーを挿入してなり上記変調用レーザー光を導入する
単一モード光ファイバーと、上記音響センサーを通過し
た変調レーザー光と上記参照レーザー光との位相差を一
定とする光路長調整部と、上記変調レーザー光と上記参
照レーザー光とを干渉させる手段と、上記干渉手段から
出力する干渉レーザー光から音圧に比例する電気信号を
取り出す信号処理装置とを具えたことを特徴とする。To this end, the invention of claim 1 provides a coil-like single-mode optical fiber and a spectroscopic means for dividing the laser light output from the laser light source into a reference laser light and a modulating laser light. A single-mode optical fiber that inserts an acoustic sensor that is wound around and introduces the modulating laser light, and an optical path length that makes the phase difference between the modulated laser light that has passed through the acoustic sensor and the reference laser light constant. An adjusting unit, means for causing the modulated laser light and the reference laser light to interfere with each other, and a signal processing device for extracting an electric signal proportional to sound pressure from the interference laser light output from the interference means, To do.
【０００６】また、請求項２の発明は、請求項１におい
て、そのコイル状音響センサーを単位センサーとする複
数の単位センサーを円環状に配設してなる円周卓音響セ
ンサーと、同円周卓音響センサーの各単位センサーに音
波が到着する時間差及び音圧ベクトルの合成に基づいて
同音波の音源の方向を求める情報処理装置とを具えたこ
とを特徴とする。According to a second aspect of the present invention, there is provided a circular table acoustic sensor according to the first aspect, in which a plurality of unit sensors each having the coiled acoustic sensor as a unit sensor are arranged in an annular shape, and the same circular circumference. An information processing device for determining the direction of the sound source of the sound wave based on the time difference of arrival of the sound wave and the composition of the sound pressure vector at each unit sensor of the desk acoustic sensor.
【０００７】[0007]
【作用】このような構成によれば、レーザー光源からの
出力光は、干渉用レーザー光Ａと参照レーザー光Ｂとに
２分され、干渉用レーザー光Ａは光ファイバーコイル７
を経てセンサー用ファイバー４へ導かれる。その際、水
中音圧により位相変調された光ファイバーコイル７の干
渉用レーザー光Ａは参照レーザー光ファイバー３を通っ
た参照レーザー光Ｂと干渉し、光検出器５により音圧に
比例した電気信号となる。こうして、音圧に比例した位
相変調（変調角；△φ）を受けた干渉用レーザー光と参
照レーザー光との干渉の結果、光検出器の出力（電圧
等）は ｉ＝α｛Ｐｒ＋Ｐｓ＋２β〔√（Ｐｒ・Ｐｓ）〕｝ｃｏ
ｓ（φ0 ＋△φ） となる。ただし、 α：検出器感度 Ｐｒ：参照光強度 Ｐｓ：信号光強度 β：干渉効率 φ0 ：音波のないときの干渉用レーザー光と参照レーザ
ー光の位相差 である。ここで、一般に△φは小さいため、φ0 ＝π／
２となるように参照レーザー光の光ファイバーの長さを
調節することにより、出力ｉの変化分は △ｉ≒２αβ〔√（Ｐｒ・Ｐｓ）〕△φ となり、音圧に比例した電圧等の出力が得られ、高精度
の水中音響測定が可能となる。According to this structure, the output light from the laser light source is divided into the interference laser light A and the reference laser light B, and the interference laser light A is diverted into the optical fiber coil 7.
Is led to the sensor fiber 4. At that time, the interfering laser light A of the optical fiber coil 7 phase-modulated by the underwater sound pressure interferes with the reference laser light B passing through the reference laser optical fiber 3 and becomes an electric signal proportional to the sound pressure by the photodetector 5. . In this way, as a result of the interference between the interference laser light and the reference laser light that have undergone the phase modulation (modulation angle; Δφ) proportional to the sound pressure, the output (voltage or the like) of the photodetector is i = α {Pr + Ps + 2β [√ (Pr / Ps)]} co
s (φ 0 + Δφ). Here, α: detector sensitivity Pr: reference light intensity Ps: signal light intensity β: interference efficiency φ 0 : phase difference between interference laser light and reference laser light in the absence of sound waves. Here, since Δφ is generally small, φ 0 = π /
By adjusting the length of the optical fiber of the reference laser light so that it becomes 2, the change of the output i becomes Δi≈2αβ [√ (Pr · Ps)] Δφ, and the output of the voltage proportional to the sound pressure. Is obtained, and highly accurate underwater acoustic measurement becomes possible.
【０００８】[0008]
【実施例】本発明を水中音響計測に適用した一実施例を
図面について説明すると、図１はその第１実施例を示す
全体系統図、図２は図１のセンサーコイル部を示す拡大
図、図３は本発明の第２実施例を示す平面図、図４は図
３の作用説明図、図５は図４による音源方向の分析処理
要領を示す説明図である。DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment in which the present invention is applied to underwater acoustic measurement will be described. FIG. 1 is an overall system diagram showing the first embodiment, and FIG. 2 is an enlarged view showing the sensor coil portion of FIG. 3 is a plan view showing a second embodiment of the present invention, FIG. 4 is an operation explanatory view of FIG. 3, and FIG. 5 is an explanatory view showing a sound source direction analysis processing procedure according to FIG.
【０００９】まず、ず１に示す第１実施例において、レ
ーザー光源１から発射されるレーザー光は、ハーフミラ
ー２により反射光Ｂと透過光Ａに２分される。反射光Ｂ
は参照レーザー光として単一モード光ファイバー３及び
ハーフミラー分光器２′を経て光検出器５に入る。一
方、ハーフミラー２からの透過光Ａは干渉用レーザー光
として光ファイバー音響センサーコイル７及び単一モー
ド光ファイバー４を経て分光器（ハ−フミラ−）２′に
入る。ここで、参照光Ｂと干渉光Ａとは光検出器５を経
て情報処理装置６により同期的に処理される。このよう
な第１実施例によれば、音響センサーコイル７はコイル
状に巻回された形（図２）となっているので、水中音圧
を受ける際に単位時間当たりの音響吸収エネルギを大き
くすることができ、単なる一直線状の光ファイバーに比
べて大きな音響エネルギを吸収し、光ファイバーの屈折
率の変化により干渉光Ａの位相が大きく変化する。First, in the first embodiment shown in FIG. 1, the laser light emitted from the laser light source 1 is divided into a reflected light B and a transmitted light A by the half mirror 2. Reflected light B
Enters the photodetector 5 as a reference laser beam through the single mode optical fiber 3 and the half mirror spectroscope 2 '. On the other hand, the transmitted light A from the half mirror 2 passes through the optical fiber acoustic sensor coil 7 and the single mode optical fiber 4 as a laser light for interference and enters the spectroscope (harm mirror) 2 '. Here, the reference light B and the interference light A are processed synchronously by the information processing device 6 via the photodetector 5. According to the first embodiment as described above, the acoustic sensor coil 7 has a coiled shape (FIG. 2), so that when the underwater sound pressure is received, the acoustically absorbed energy per unit time is increased. It is possible to absorb a large amount of acoustic energy as compared with a mere linear optical fiber, and the phase of the interference light A largely changes due to the change of the refractive index of the optical fiber.
【００１０】このような構造によれば、レーザー光源か
らの出力光は、干渉用レーザー光Ａと参照レーザー光Ｂ
とに２分され、干渉用レーザー光Ａは光ファイバーコイ
ル７を経てセンサー用ファイバー４へ導かれる。その
際、水中音圧により位相変調された光ファイバーコイル
７の干渉用レーザー光Ａは参照レーザー光ファイバー３
を通った参照レーザー光Ｂと干渉し、光検出器５により
音圧に比例した電気信号となる。こうして、音圧に比例
した位相変調（変調角；△φ）を受けた干渉用レーザー
光と参照レーザー光との干渉の結果、光検出器の出力
（電圧等）は ｉ＝α｛Ｐｒ＋Ｐｓ＋２β√〔（Ｐｒ・Ｐｓ）〕｝ｃｏ
ｓ（φ0 ＋△φ） となる。ただし、 α：検出器感度 Ｐｒ：参照光強度 Ｐｓ：信号光強度 β：干渉効率 φ0 ：音波のないときの干渉用レーザー光と参照レーザ
ー光の位相差 である。ここで、一般に△φは小さいため、φ0 ＝π／
２となるように図１の鎖線枠で示すように、参照レーザ
ー光の光ファイバーの長さを調節することにより、出力
ｉの変化分は △ｉ≒２αβ√〔（Ｐｒ・Ｐｓ）〕△φ となり、音圧に比例した電圧等の出力が得られ、高精度
の水中音響測定が可能となる。なお、音響センサーコイ
ル７を図２に示すように、ある程度指向性を持たすこと
で音源の方向を求めることもできる。With this structure, the output light from the laser light source is the interference laser light A and the reference laser light B.
The laser light A for interference is guided to the sensor fiber 4 via the optical fiber coil 7. At that time, the interference laser light A of the optical fiber coil 7 phase-modulated by the underwater sound pressure is the reference laser optical fiber 3.
It interferes with the reference laser beam B that has passed through, and the photodetector 5 produces an electrical signal proportional to the sound pressure. In this way, as a result of the interference between the interference laser light and the reference laser light that have undergone phase modulation (modulation angle; Δφ) proportional to the sound pressure, the output (voltage or the like) of the photodetector is i = α {Pr + Ps + 2β√ [ (Pr / Ps)]} co
s (φ 0 + Δφ). Here, α: detector sensitivity Pr: reference light intensity Ps: signal light intensity β: interference efficiency φ 0 : phase difference between interference laser light and reference laser light in the absence of sound waves. Here, since Δφ is generally small, φ 0 = π /
By adjusting the length of the optical fiber of the reference laser light as shown by the chain line frame in FIG. 1 so that it becomes 2, the change of the output i becomes Δi≈2αβ√ [(Pr · Ps)] Δφ , The output of voltage, etc., which is proportional to the sound pressure is obtained, which enables highly accurate underwater acoustic measurement. It is also possible to obtain the direction of the sound source by giving the acoustic sensor coil 7 a certain degree of directivity as shown in FIG.
【００１１】次に、図３に示す第２実施例においては、
レーザー光源１及び光検出器５は円周卓８の内に挿入さ
れたボックス９に内蔵され、レーザー光源１から発射さ
れるレーザー光は単一モード光ファイバー４を経て円周
卓８を形成する単一モード光ファイバーからなる各音響
センサーコイル７ｓを通ったのち、単一モード光ファイ
バー４を経て光検出器５に導入される。Next, in the second embodiment shown in FIG.
The laser light source 1 and the photodetector 5 are built in a box 9 inserted in a circular table 8, and the laser light emitted from the laser light source 1 forms a circular table 8 through a single mode optical fiber 4. After passing through each acoustic sensor coil 7 s composed of a single mode optical fiber, it is introduced into the photodetector 5 via the single mode optical fiber 4.
【００１２】このような円周卓８を形成する音響センサ
ーコイル部によれば、図４に示すように、複数の単位音
響センサーコイル７ｓに指向性を持たせておくことで、
音波つまり音圧に対する受信レベルが最大である単位音
響センサーコイル７ｓの方向として音源の方向を求める
ことができる。ここで、音源方向を高精度で求めるため
に、図４〜図５に示すように、ある音波面について最初
にこれを検出する単位音響センサー（図中ハッチングを
施した部分）から他の各単位音響センサーまでの時間遅
れａ，ｂ，ｃ・・・を考慮して情報処理装置６にて同一
音波面に対する各単位センサーコイルの受信レベルの合
成ベクトルを作成し、精度の高い音源方向を求めるので
ある。According to the acoustic sensor coil portion forming the circular table 8 as described above, as shown in FIG. 4, by directing a plurality of unit acoustic sensor coils 7s,
The direction of the sound source can be obtained as the direction of the unit acoustic sensor coil 7s having the maximum reception level for sound waves, that is, sound pressure. Here, in order to obtain the sound source direction with high accuracy, as shown in FIGS. 4 to 5, from a unit acoustic sensor (hatched portion in the figure) that first detects a sound wave surface to each of other units. In consideration of the time delays a, b, c ... to the acoustic sensor, the information processing device 6 creates a composite vector of the reception levels of the respective unit sensor coils with respect to the same sound wave surface to obtain a highly accurate sound source direction. is there.
【００１３】[0013]
【発明の効果】このような各実施例によれば、より高感
度かつ高精度の水中音響のパッシブな測定が可能とな
る。また、光ファイバーは耐食性に優れているので、セ
ンサー部の腐食対策が容易であり、Ｓ／Ｎ比が優れ、高
感度かつ測定精度が高い。According to each of the embodiments described above, it is possible to perform passive measurement of underwater sound with higher sensitivity and accuracy. Further, since the optical fiber is excellent in corrosion resistance, it is easy to take measures against corrosion of the sensor portion, the S / N ratio is excellent, the sensitivity is high, and the measurement accuracy is high.
【００１４】要するに請求項１の発明によれば、レーザ
ー光源から出力するレーザー光を参照レーザー光と変調
用レーザー光とに２分する分光手段と、単一モード光フ
ァイバーをコイル状に巻回してなる音響センサーを挿入
してなり上記変調用レーザー光を導入する単一モード光
ファイバーと、上記音響センサーを通過した変調レーザ
ー光と上記参照レーザー光との位相差を一定とする光路
長調整部と、上記変調レーザー光と上記参照レーザー光
とを干渉させる手段と、上記干渉手段から出力する干渉
レーザー光から音圧に比例する電気信号を取り出す信号
処理装置とを具えたことにより、Ｓ／Ｎ比が優れ、高感
度かつ高精度で船上からの深海部測定にも好適な高性能
かつ長寿命の光ファイバーパッシブ音響センサーを得る
から、本発明は産業上極めて有益なものである。In short, according to the first aspect of the invention, a single mode optical fiber and a spectroscopic means for dividing the laser light output from the laser light source into the reference laser light and the modulation laser light are wound in a coil shape. A single-mode optical fiber that inserts an acoustic sensor and introduces the modulating laser light, an optical path length adjusting unit that makes the phase difference between the modulated laser light that has passed through the acoustic sensor and the reference laser light constant, and The S / N ratio is excellent because the device has means for causing the modulated laser light and the reference laser light to interfere with each other and a signal processing device for extracting an electric signal proportional to sound pressure from the interference laser light output from the interference means. The present invention provides a high-performance and long-life optical fiber passive acoustic sensor that is highly sensitive and accurate and is suitable for deep-sea measurement from a ship. Those above extremely beneficial.
【００１５】また、請求項２の発明によれば、請求項１
において、そのコイル状音響センサーを単位センサーと
する複数の単位センサーを円環状に配設してなる円周卓
音響センサーと、同円周卓音響センサーの各単位センサ
ーに音波が到着する時間差及び音圧ベクトルの合成に基
づいて同音波の音源の方向を求める情報処理装置とを具
えたことにより、請求項１の発明による効果のほか、か
なりの精度で音源の方向を求めることができるので、本
発明は産業上極めて有益なものである。According to the invention of claim 2, claim 1
In the above, a circular table acoustic sensor in which a plurality of unit sensors having the coiled acoustic sensor as a unit sensor are arranged in an annular shape, and a time difference and a sound that a sound wave arrives at each unit sensor of the circular table acoustic sensor. Since the information processing apparatus for determining the direction of the sound source of the same sound wave based on the composition of the pressure vector is provided, the direction of the sound source can be determined with considerable accuracy in addition to the effect according to the invention of claim 1. The invention is extremely useful in industry.
【図１】本発明の第１実施例を示す全体系統図である。FIG. 1 is an overall system diagram showing a first embodiment of the present invention.
【図２】図１のセンサーコイル部を示す拡大図である。FIG. 2 is an enlarged view showing a sensor coil unit of FIG.
【図３】本発明の第２実施例を示す全体系統図である。FIG. 3 is an overall system diagram showing a second embodiment of the present invention.
【図４】図３の作用説明図である。FIG. 4 is an explanatory view of the operation of FIG.
【図５】図４の音源方向を求める作用説明図である。FIG. 5 is an explanatory view of the operation for obtaining the sound source direction in FIG.
【図６】従来の水中音響測定装置を示す概念図である。FIG. 6 is a conceptual diagram showing a conventional underwater acoustic measurement device.
【符号の説明】 １ レーザー光源 ２ ハーフミラー ２′ ハーフミラー ３，４ 単一モード光ファイバー ５ 光検出器 ６ 情報処理装置 ７ 音響センサーコイル ７ｓ単位音響センサ−コイル ８ 円周卓 Ａ 干渉用レーザー光（透過光） Ｂ 参照レーザー光（反射光）[Explanation of symbols] 1 laser light source 2 half mirror 2'half mirror 3,4 single mode optical fiber 5 photodetector 6 information processing device 7 acoustic sensor coil 7s unit acoustic sensor-coil 8 circular table A laser light for interference ( Transmitted light) B Reference laser light (reflected light)
Claims (2)
参照レーザー光と変調用レーザー光とに２分する分光手
段と、単一モード光ファイバーをコイル状に巻回してな
る音響センサーを挿入してなり上記変調用レーザー光を
導入する単一モード光ファイバーと、上記音響センサー
を通過した変調レーザー光と上記参照レーザー光との位
相差を一定とする光路長調整部と、上記変調レーザー光
と上記参照レーザー光とを干渉させる手段と、上記干渉
手段から出力する干渉レーザー光から音圧に比例する電
気信号を取り出す信号処理装置とを具えたことを特徴と
する光ファイバーパッシブ音響センサー。1. A spectroscopic means for dividing a laser beam output from a laser light source into a reference laser beam and a modulating laser beam, and an acoustic sensor formed by winding a single mode optical fiber in a coil shape. A single-mode optical fiber for introducing a laser light for modulation, an optical path length adjusting unit for making the phase difference between the modulated laser light passing through the acoustic sensor and the reference laser light constant, the modulated laser light and the reference laser light An optical fiber passive acoustic sensor comprising: means for interfering with each other; and a signal processing device for extracting an electric signal proportional to sound pressure from the interference laser light output from the interference means.
ンサーを単位センサーとする複数の単位センサーを円環
状に配設してなる円周卓音響センサーと、同円周卓音響
センサーの各単位センサーに音波が到着する時間差及び
音圧ベクトルの合成に基づいて同音波の音源の方向を求
める情報処理装置とを具えたことを特徴とする光ファイ
バーパッシブ音響センサー。2. The circular table acoustic sensor according to claim 1, wherein a plurality of unit sensors each having the coiled acoustic sensor as a unit sensor are arranged in an annular shape, and each unit sensor of the circular table acoustic sensor. An optical fiber passive acoustic sensor, comprising: an information processing device that determines the direction of the sound source of the sound wave based on the time difference of arrival of the sound wave and the synthesis of the sound pressure vector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6457394A JPH07243902A (en) | 1994-03-08 | 1994-03-08 | Optical fiber passive acoustic sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6457394A JPH07243902A (en) | 1994-03-08 | 1994-03-08 | Optical fiber passive acoustic sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07243902A true JPH07243902A (en) | 1995-09-19 |
Family
ID=13262113
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6457394A Withdrawn JPH07243902A (en) | 1994-03-08 | 1994-03-08 | Optical fiber passive acoustic sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07243902A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2748108A1 (en) * | 1996-04-26 | 1997-10-31 | Marconi Gec Ltd | FIBER OPTIC DETECTION SYSTEM |
| DE10112458C1 (en) * | 2001-03-15 | 2002-10-10 | Hmt Ag | Testing of acoustic wave source propagating in liquid medium involves detecting change in intensity of transmitted light passed through liquid medium perpendicular to propagation direction |
| WO2003002956A1 (en) * | 2001-06-27 | 2003-01-09 | Center For Advanced Science And Technology Incubation, Ltd. | Device and method for vibration measurement |
| WO2005095909A1 (en) * | 2004-03-30 | 2005-10-13 | Toudai Tlo, Ltd. | Vibration measuring device |
| US7536911B2 (en) * | 2003-09-22 | 2009-05-26 | Hyeung-Yun Kim | Diagnostic systems of optical fiber coil sensors for structural health monitoring |
| CN105181112A (en) * | 2015-10-22 | 2015-12-23 | 哈尔滨工业大学 | Diaphragm type low-fineness F-P optical fiber sound pressure transducer based on FBG |
| CN105241541A (en) * | 2015-10-22 | 2016-01-13 | 哈尔滨工业大学 | FBG-based diaphragm type high-definition F-P optical fiber sound pressure sensor |
-
1994
- 1994-03-08 JP JP6457394A patent/JPH07243902A/en not_active Withdrawn
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2748108A1 (en) * | 1996-04-26 | 1997-10-31 | Marconi Gec Ltd | FIBER OPTIC DETECTION SYSTEM |
| DE10112458C1 (en) * | 2001-03-15 | 2002-10-10 | Hmt Ag | Testing of acoustic wave source propagating in liquid medium involves detecting change in intensity of transmitted light passed through liquid medium perpendicular to propagation direction |
| WO2003002956A1 (en) * | 2001-06-27 | 2003-01-09 | Center For Advanced Science And Technology Incubation, Ltd. | Device and method for vibration measurement |
| US7262834B2 (en) | 2001-06-27 | 2007-08-28 | Toudai Tlo, Inc. | Sensor for measuring velocity of vibration using light waveguide |
| US7536911B2 (en) * | 2003-09-22 | 2009-05-26 | Hyeung-Yun Kim | Diagnostic systems of optical fiber coil sensors for structural health monitoring |
| WO2005095909A1 (en) * | 2004-03-30 | 2005-10-13 | Toudai Tlo, Ltd. | Vibration measuring device |
| CN105181112A (en) * | 2015-10-22 | 2015-12-23 | 哈尔滨工业大学 | Diaphragm type low-fineness F-P optical fiber sound pressure transducer based on FBG |
| CN105241541A (en) * | 2015-10-22 | 2016-01-13 | 哈尔滨工业大学 | FBG-based diaphragm type high-definition F-P optical fiber sound pressure sensor |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4297887A (en) | High-sensitivity, low-noise, remote optical fiber | |
| US4770535A (en) | Distributed sensor array and method using a pulsed signal source | |
| US4238856A (en) | Fiber-optic acoustic sensor | |
| US4313185A (en) | Acoustic vibration sensor and sensing system | |
| JPS6345047B2 (en) | ||
| US4310905A (en) | Acoustical modulator for fiber optic transmission | |
| JP4751118B2 (en) | Optical detection sensor | |
| JPS6159216A (en) | Acoustic type fluid flowmeter | |
| JPH07243902A (en) | Optical fiber passive acoustic sensor | |
| IL135281A (en) | Small optical microphone/sensor | |
| JPS6018100A (en) | Microphone | |
| Wen et al. | High-sensitivity fiber-optic ultrasound sensors for medical imaging applications | |
| KR101832075B1 (en) | Acoustic converter, acoustic converter system, optical hydrophone, acoustic converter array and watercraft | |
| US6542244B1 (en) | Variable sensitivity acoustic transducer | |
| JPS61270683A (en) | Light applied measuring instrument | |
| JPS5948668A (en) | Optical fiber speedometer | |
| CN116299147B (en) | One-dimensional structure internal sound source positioning method based on acoustic coherence technology | |
| SU1638580A1 (en) | Acoustic pressure gauge | |
| RU2091984C1 (en) | Fiber-optic sound pressure gradient detector | |
| SU1449891A1 (en) | Transceiving device of acoustic microscope | |
| SU811118A1 (en) | Apparatus for determining pulsations of optical refraction index gradient | |
| ATE222014T1 (en) | ULTRASONIC MEASUREMENT DEVICE | |
| SU995034A1 (en) | Device for measuring pulse magnetic field strength | |
| JPS6250625A (en) | Optical fiber acoustic sensor | |
| JPH04318455A (en) | Ultrasonic concentration measuring instrument |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20010508 |