JP3263897B2 - High water pressure cylindrical optical fiber acoustic sensor - Google Patents
High water pressure cylindrical optical fiber acoustic sensorInfo
- Publication number
- JP3263897B2 JP3263897B2 JP00792896A JP792896A JP3263897B2 JP 3263897 B2 JP3263897 B2 JP 3263897B2 JP 00792896 A JP00792896 A JP 00792896A JP 792896 A JP792896 A JP 792896A JP 3263897 B2 JP3263897 B2 JP 3263897B2
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- Prior art keywords
- optical fiber
- acoustic sensor
- pressure
- cylinder
- cavity
- Prior art date
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- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は円筒型光ファイバ音
響センサに関し、特に音圧を光の位相変化に変換して水
中音波を検出する高耐水圧円筒型光ファイバ音響センサ
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical optical fiber acoustic sensor, and more particularly, to a high water pressure resistant cylindrical optical fiber acoustic sensor for detecting underwater sound waves by converting sound pressure into a phase change of light.
【０００２】[0002]
【従来の技術】一般的な円筒型光ファイバ音響センサに
ついては、Ｇ．Ｆ．Ｍｃｄｅａｒｍｏｎによる「呼吸振
動型の光ファイバ水中聴音機の理論的解析：Ｔｈｅｏｒ
ｅｔｉｃａｌ Ａｎａｌｙｓｉｓ ｏｆ ａ Ｐｕｓｈ
−Ｐｕｌｌ Ｆｉｂｅｒ−Ｏｐｔｉｃ Ｈｙｄｒｏｐｈ
ｏｎ」と題する下記の文献によって開示されている。 文献名：Ｊｏｕｒｎａｌ ｏｆ Ｌｉｇｈｔｗａｖｅ
Ｔｅｃｈｎｏｌｏｇｙ，［ｖｏｌ．Ｌｔ・５］，Ｎｏ．
５，ｐｐ６４７〜６５２，Ｍａｙ１９８７（米）2. Description of the Related Art A general cylindrical optical fiber acoustic sensor is disclosed in G. K .; F. "Theoretical Analysis of a Respiratory Vibration Type Fiber Optic Underwater Hearing Aid by McDearmon: Theor
electrical Analysis of a Push
-Pull Fiber-Optic Hydroph
and "on". Article name: Journal of Lightwave
Technology, [vol. Lt.5], No.
5, pp 647-652, May 1987 (US)
【０００３】上記の文献に開示されている円筒型光ファ
イバ音響センサは、２つの円筒の呼吸振動を利用したも
ので、図５にこのセンサの模式断面図を示す。図におい
て、センサは所定の長さを持つ外円筒１及び内円筒２の
２つの円筒を同心円状に配置した二重円筒型のもので、
円筒の両端に蓋３を取り付け、各円筒の間に形成される
等間隔な空胴部を空気室４として形成している。外円筒
１の内側面及び内円筒２の外側面には、光ファイバ５，
５ａがそれぞれコイル状に巻回状態で設置されている構
造となっている。[0003] The cylindrical optical fiber acoustic sensor disclosed in the above document utilizes respiratory vibration of two cylinders, and FIG. 5 is a schematic cross-sectional view of this sensor. In the figure, the sensor is a double cylinder type in which two cylinders having a predetermined length, an outer cylinder 1 and an inner cylinder 2, are arranged concentrically.
Lids 3 are attached to both ends of the cylinder, and equally spaced cavities formed between the cylinders are formed as air chambers 4. Optical fibers 5 are provided on the inner surface of the outer cylinder 1 and the outer surface of the inner cylinder 2.
5a is installed in a coiled state.
【０００４】ここで、センサに音圧が加わると、円筒の
内外に圧力差が生じるため、両円筒は振動方向が互いに
逆方向の呼吸振動をする。この時、両円筒に巻き付けた
光ファイバ５，５ａも互いに逆方向に伸び縮みするた
め、光ファイバ５，５ａ内を伝搬しているレーザ光の位
相が変化する。そこで、この音圧に比例するレーザ光の
位相変化量を光の干渉を利用した周知の干渉計の原理に
より、音圧を高感度で検出するようになっている。[0004] When sound pressure is applied to the sensor, a pressure difference is generated between the inside and outside of the cylinder, so that the two cylinders perform respiratory vibrations whose vibration directions are opposite to each other. At this time, since the optical fibers 5 and 5a wound around the two cylinders also expand and contract in opposite directions, the phase of the laser light propagating in the optical fibers 5 and 5a changes. Accordingly, the sound pressure is detected with high sensitivity based on the principle of a well-known interferometer utilizing the interference of light with respect to the phase change amount of the laser light which is proportional to the sound pressure.
【０００５】[0005]
【発明が解決しようとする課題】上述のような従来の円
筒型光ファイバ音響センサは、内・外円筒の間の空胴部
を蓋で閉じ、かつ密閉して空気室を構成しているため、
圧力バランス構造の円筒型光ファイバ音響センサとはな
っていない。従って、これを水中において使用する時は
一般に耐水圧が低くなり、例えば現在要望されるような
深々度の水中では利用できないという問題がある。In the above-mentioned conventional cylindrical optical fiber acoustic sensor, the air chamber is formed by closing and sealing the cavity between the inner and outer cylinders with a lid. ,
It is not a cylindrical optical fiber acoustic sensor having a pressure balance structure. Therefore, when it is used in water, the water pressure resistance is generally low, and for example, there is a problem that it cannot be used in deep water as currently required.
【０００６】[0006]
【課題を解決するための手段】本発明に係る高耐水圧円
筒型光ファイバ音響センサは、１つの円筒体による単円
筒型構造で構成され、１つの円筒体の内部を構成する空
胴部をその両端においてそれぞれ閉じる蓋を有し、かつ
円筒体の側面に沿って巻回された光ファイバを備えてな
る円筒型光ファイバ音響センサであって、蓋の内の一方
の側の蓋に形成され、空胴部と円筒体の外周部との静水
圧を等しくする開口部を有するものである。ここで、前
記の開口部の径は、この開口部と空胴部に相当する間隙
部とによって構成されるヘルムホルツ共鳴器におけるヘ
ルムホルツ共振周波数以上の周波数の音波は通過しない
大きさの径であることが必要である。また、光ファイバ
は円筒体の側面及び蓋の内の開口部の形成されていない
蓋の側面に設けられていることが好ましい。SUMMARY OF THE INVENTION A high-pressure-resistant cylindrical optical fiber acoustic sensor according to the present invention has a single-cylindrical structure composed of a single cylindrical body, and has a hollow portion forming the inside of one cylindrical body. A cylindrical optical fiber acoustic sensor having a lid closed at both ends thereof, and comprising an optical fiber wound along a side surface of the cylindrical body, wherein the acoustic sensor is formed on a lid on one side of the lid. And an opening for equalizing the hydrostatic pressure between the cavity and the outer peripheral portion of the cylindrical body. Here, the diameter of the opening is such that the sound wave having a frequency equal to or higher than the Helmholtz resonance frequency in the Helmholtz resonator formed by the opening and the gap corresponding to the cavity does not pass through. is necessary. Further, it is preferable that the optical fiber is provided on the side of the cylindrical body and on the side of the lid where the opening in the lid is not formed.
【０００７】なお、ヘルムホルツ共鳴器は、よく知られ
ているように、本発明における蓋及び円筒を剛体とした
時の共振回路を構成する音響回路であり、次のような記
述によって定量的な説明がなされている。この場合、液
体の粘性等が音響抵抗ｒＡ（電気回路の抵抗Ｒに相
当）、開口部（オリフィス）を満たしている液体の質量
ｍＡは音響回路ではイナータンス（電気回路のインダク
タンスＬに相当）、円筒の容量ＣＡは音響コンプライア
ンス（電気回路のキャパシタンスＣに相当）として作用
する。従って、圧力バランスのような構造では、「オリ
フィス−円筒間の容量」により「Ｒ−Ｌ−Ｃ」の共振回
路が構成されたことにより、このような音響回路をヘル
ムホルツ共振器と呼んでいる。そして、ｍＡ、ＣＡ及び
ヘルムホルツ共振周波数ｆは、次式のような式で表され
ている。 ｍＡ＝Ｌρ／Ｓ ＣＡ＝Ｗ／ρｃ２ ｆ＝１／｛２π（ｍＡ×ＣＡ）１／２｝ ここで、Ｌ：オリフィスの長さ、ρ：液体の密度、Ｓ：
オリフィスの面積、Ｗ：円筒の容積、ｃ：音速である。
つまり、開口部と空胴部とは、音響機器（楽器等）の胴
体に設けられた穴と空胴（キャビティ）との関係に擬似
し、この構造は音波（音響）に対して一種のヘルムホル
ツの共鳴器（共振器に同じ）を構成している。[0007] As is well known, the Helmholtz resonator is an acoustic circuit constituting a resonance circuit when the lid and the cylinder in the present invention are rigid, and is quantitatively described by the following description. Has been made. In this case, the viscosity or the like of the liquid is an acoustic resistance rA (corresponding to the resistance R of the electric circuit), the mass mA of the liquid filling the opening (orifice) is an inertance (corresponding to the inductance L of the electric circuit) in the acoustic circuit, and a cylinder. Acts as acoustic compliance (corresponding to the capacitance C of the electric circuit). Accordingly, in a structure such as pressure balance, a resonance circuit of “RLC” is formed by “capacity between orifice and cylinder”, and such an acoustic circuit is called a Helmholtz resonator. The mA, CA and Helmholtz resonance frequency f are expressed by the following equations. mA = Lρ / S CA = W / ρc 2 f = 1 / {2π (mA × CA) 1/2 } where L: length of orifice, ρ: density of liquid, S:
The area of the orifice, W: the volume of the cylinder, and c: the speed of sound.
In other words, the opening and the cavity simulate the relationship between a hole provided in the body of an acoustic device (musical instrument or the like) and the cavity (cavity), and this structure is a kind of Helmholtz against sound waves (acoustics). (Same as the resonator).
【０００８】本発明においては、１つの円筒（これを以
後単円筒という）の空胴部を円筒の両端部で密閉するよ
うに使用された蓋の内の一方の側の蓋にオリフィス状の
開口部を設けているから、このセンサを水中に設置乃至
浮游させた場合、開口部を介して空胴部内とその外周部
とが通じて、空胴部内と円筒体の外周部とは静水圧が等
しくなるので、圧力バランス構造の光ファイバ音響セン
サが構成される。この場合、上記のような圧力バランス
型の光ファイバ音響センサは前述のヘルムホルツの共振
器として働くことを利用したものに相当し、その周波数
特性は次のように説明される。一般に、ヘルムホルツの
共振器では、ヘルムホルツの共振周波数以下の周波数の
音波（静水圧を含む）はオリフィスを通過する。そのた
め、単円筒型光ファイバ音響センサは、ヘルムホルツ共
振周波数以下の周波数では円筒内側の圧力と音響センサ
周囲の外側圧力が平衡して円筒は呼吸振動は生じない。
従って、それを取り巻く光ファイバは長さの変化は起き
ない。一方、ヘルムホルツ共振周波数以上の周波数の音
波はオリフィスを通過できないので、円筒に呼吸振動が
起き、光ファイバにも長さの変化がおきる。つまり、圧
力バランス型の光ファイバ音響センサの場合の受波感度
の周波数特性は、図４に示すように、遮断周波数（ヘル
ムホルツ共振による）を持つ特性になる。In the present invention, an orifice-like opening is formed in one of the lids used to seal the cavity of one cylinder (hereinafter referred to as a single cylinder) at both ends of the cylinder. When the sensor is installed or floated in water, the inside of the cavity and the outer periphery thereof pass through the opening, and the hydrostatic pressure between the inside of the cavity and the outer periphery of the cylindrical body is provided. Since they are equal, an optical fiber acoustic sensor having a pressure balance structure is formed. In this case, the pressure-balanced optical fiber acoustic sensor as described above is equivalent to the one utilizing the function as the above-described Helmholtz resonator, and its frequency characteristic is described as follows. Generally, in a Helmholtz resonator, sound waves (including hydrostatic pressure) having a frequency equal to or lower than the Helmholtz resonance frequency pass through the orifice. Therefore, in the single-cylinder optical fiber acoustic sensor, at a frequency lower than the Helmholtz resonance frequency, the pressure inside the cylinder and the outside pressure around the acoustic sensor are balanced, and the cylinder does not generate respiratory vibration.
Therefore, the optical fiber surrounding it does not change in length. On the other hand, since a sound wave having a frequency higher than the Helmholtz resonance frequency cannot pass through the orifice, respiratory vibration occurs in the cylinder, and the length of the optical fiber changes. That is, the frequency characteristic of the wave receiving sensitivity in the case of the pressure-balanced optical fiber acoustic sensor has a cutoff frequency (due to Helmholtz resonance), as shown in FIG.
【０００９】換言すると、開口部と空胴部とは、音響機
器（楽器等）の穴と空胴との関係に擬似し、この構造は
前述のように音波（音響）に対して一種のヘルムホルツ
の共鳴器を構成している。従って、空胴部の容積と開口
部の径で決まるヘルムホルツ共振周波数以下の周波数の
音波はこの開口部を通過するが、ヘルムホルツ共振周波
数以上の周波数の音波は開口部を通過しない。そこで、
この構成において、ヘルムホルツ共振周波数以上の周波
数の音波をセンサのプローブとして使用すると、センサ
の外側には「静水圧＋この音波の音圧」が印加される
が、空胴部には静水圧のみしか加わらない。従って、円
筒の内側と外側に圧力不平衡が生じ、内・外筒はこの音
波の音圧で呼吸振動をするようになる。In other words, the opening and the cavity simulate the relationship between the hole of the acoustic equipment (musical instrument and the like) and the cavity, and this structure is a kind of Helmholtz for sound waves (acoustics) as described above. Of the resonator. Accordingly, sound waves having a frequency equal to or lower than the Helmholtz resonance frequency determined by the volume of the cavity and the diameter of the opening pass through the opening, but sound waves having a frequency equal to or higher than the Helmholtz resonance frequency do not pass through the opening. Therefore,
In this configuration, if a sound wave having a frequency equal to or higher than the Helmholtz resonance frequency is used as a probe of the sensor, "hydrostatic pressure + sound pressure of this sound wave" is applied to the outside of the sensor, but only the hydrostatic pressure is applied to the cavity. Will not join. Therefore, pressure imbalance occurs between the inside and the outside of the cylinder, and the inner and outer cylinders respire and vibrate at the sound pressure of this sound wave.
【００１０】[0010]
【発明の実施の形態】［第１の実施形態］ 図１は本発明による高耐水圧円筒型光ファイバ音響セン
サ（以下センサという）の第１の実施形態を示す模式断
面図である。図１において、所定の長さ・径を持つ単円
筒１０の両端に蓋１１及び蓋１２取り付け、単円筒１０
の内側空胴によって空胴部１３が形成されている。この
場合、蓋１１は、図示のように、円板で形成され、蓋１
２は蓋１１よりも厚さの厚い円板で形成されている。ま
た、単円筒１０の外側面には光ファイバ１４（第１の光
ファイバ）が、蓋１２の外側面には光ファイバ１５（第
２の光ファイバ）がそれぞれコイル状に巻回されて、干
渉計（後述の図２参照）を構成する構造となっている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 is a schematic sectional view showing a first embodiment of a highly water-resistant cylindrical optical fiber acoustic sensor (hereinafter referred to as a sensor) according to the present invention. In FIG. 1, a lid 11 and a lid 12 are attached to both ends of a single cylinder 10 having a predetermined length and diameter.
A cavity portion 13 is formed by the inner cavity of. In this case, the lid 11 is formed of a disk as shown in FIG.
2 is formed of a disk having a thickness greater than that of the lid 11. Further, an optical fiber 14 (first optical fiber) is wound on the outer surface of the single cylinder 10 and an optical fiber 15 (second optical fiber) is wound on the outer surface of the lid 12 in a coil shape. (See FIG. 2 described later).
【００１１】そして、上下に２つある蓋１１，１２の
内、いずれか一方の蓋すなわち本実施例の場合蓋１１の
中心に空胴部１３に通ずるオリフィス１６が開口部とし
て設けられたセンサ構造となっている。この構造によ
り、このセンサを例えば水中に設置乃至浮游させた場
合、空胴部１３にもオリフィス１６を介して水（図に示
したセンサ周囲の液体と同じ液体）が充満するので、セ
ンサ周囲の媒体と同じ媒体で、かつ同じ静水圧で空胴部
１３を満たすことができるようになっている。A sensor structure in which an orifice 16 communicating with the cavity 13 is provided as an opening in one of the upper and lower lids 11 and 12, that is, in the present embodiment, in the center of the lid 11. It has become. With this structure, when this sensor is installed or floated in water, for example, the cavity 13 is also filled with water (the same liquid as the liquid around the sensor shown in the figure) through the orifice 16, so that the surroundings of the sensor are filled. The cavity 13 can be filled with the same medium and the same hydrostatic pressure as the medium.
【００１２】次に動作について、図３に示す前記の干渉
計の構成説明図を参照しながら説明する。まず、図３に
おいて、１０〜１６は図１で説明したセンサを構成する
部品と同一部品番号であるので、その説明は省略する。
１７はレーザダイオード（ＬＤ）１８からのレーザ光を
分岐して光ファイバ１４及び光ファイバ１５に入射させ
る光カプラであり、１７ａは光ファイバ１４及び光ファ
イバ１５から出力される各レーザ光を光電気変換器（Ｏ
／Ｅ）１９に送信するための光カプラである。Next, the operation will be described with reference to the explanatory diagram of the configuration of the interferometer shown in FIG. First, in FIG. 3, reference numerals 10 to 16 denote the same part numbers as those constituting the sensor described in FIG. 1, and a description thereof will be omitted.
Reference numeral 17 denotes an optical coupler that branches the laser light from the laser diode (LD) 18 and makes the laser light enter the optical fiber 14 and the optical fiber 15. Converter (O
/ E) an optical coupler for transmission to 19.
【００１３】一方図１において、片側の蓋１１にオリフ
ィス１６を設けておき、このセンサを例えば水中に設置
乃至浮游させた場合、空胴部１３には外周部と同じ液が
満たされる構造となっているため、空胴部１３の容積と
オリフィス１６の径で決まる静水圧を含むヘルムホルツ
共振周波数以下の周波数の音波はオリフィス１６を通過
する。従って、空胴部１３には「静水圧＋この音波の音
圧」が加わるが、センサ（円筒）の外側も同じ「静水圧
＋この音波の音圧」が印加されるので、円筒の内側と外
側の圧力が平衡し、単円筒１０はこの音波では呼吸振動
しない。しかし、この構成では、静水圧で潰れることの
ない圧力バランス構造が得られる。On the other hand, in FIG. 1, an orifice 16 is provided on one side of the lid 11, and when this sensor is installed or floated in water, for example, the cavity 13 is filled with the same liquid as the outer periphery. Therefore, sound waves having a frequency equal to or lower than the Helmholtz resonance frequency including the hydrostatic pressure determined by the volume of the cavity 13 and the diameter of the orifice 16 pass through the orifice 16. Therefore, although the “hydrostatic pressure + the sound pressure of this sound wave” is applied to the cavity 13, the same “hydrostatic pressure + the sound pressure of this sound wave” is also applied to the outside of the sensor (cylinder). The outer pressure is balanced and the single cylinder 10 does not respirate with this sound wave. However, this configuration provides a pressure balance structure that does not collapse under hydrostatic pressure.
【００１４】そこで、この構成において、ヘルムホルツ
共振周波数以上の周波数の音波をセンサのプローブとし
て使用すると、この音波はオリフィス１６を通過しなく
なるので、センサの外側には「静水圧＋この音波の音
圧」が印加されるが、空胴部１３には静水圧のみしか加
わらない。従って、円筒の内側と外側に圧力不平衡が生
じ、単円筒１０はこの音波の音圧で呼吸振動をするよう
になり、それにつれて円筒に巻き付けられた光ファイバ
１４は伸び縮みする。一方、蓋１１，１２は中空でない
剛体であるから音波による呼吸振動は生じないので、蓋
１２に巻き付けられた光ファイバ１５には長さの変化は
生じない。従って、光ファイバ１４及び光ファイバ１５
中を伝搬する光（図３のレーザダイオート１８から入射
された二筋のレーザ光）の間に位相差が生ずるようにな
る。従って、従来の技術で説明したと同様に音響センサ
として機能するようになる。つまり、、ヘルムホルツ共
振周波数以上の周波数の音波を通さない大きさの径を有
するオリフィス１６を蓋１１に設けて音響センサを構成
すればよい。このようにして、蓋１１にオリフィス１６
を有し、単円筒１０の空胴部１３に液体が満たされる構
造を有する圧力バランス構造の単円筒型の光ファイバ音
響センサは耐水圧が高く、深々度の水中でも適用できる
ようになる。Therefore, in this configuration, if a sound wave having a frequency equal to or higher than the Helmholtz resonance frequency is used as a probe of the sensor, the sound wave does not pass through the orifice 16, so that "hydrostatic pressure + sound pressure of this sound wave" appears outside the sensor. Is applied, but only the hydrostatic pressure is applied to the cavity 13. Accordingly, a pressure imbalance occurs between the inside and the outside of the cylinder, and the single cylinder 10 respires and vibrates at the sound pressure of this sound wave, and accordingly, the optical fiber 14 wound around the cylinder expands and contracts. On the other hand, since the lids 11 and 12 are rigid bodies that are not hollow, respiratory vibration due to sound waves does not occur, so that the optical fiber 15 wound around the lid 12 does not change in length. Therefore, the optical fiber 14 and the optical fiber 15
A phase difference is generated between the light propagating in the inside (the two laser beams incident from the laser die 18 in FIG. 3). Therefore, it functions as an acoustic sensor as described in the related art. In other words, the acoustic sensor may be configured by providing the orifice 16 having a diameter large enough to block sound waves having a frequency equal to or higher than the Helmholtz resonance frequency on the lid 11. Thus, the orifice 16 is attached to the lid 11.
The pressure-balanced single-cylinder optical fiber acoustic sensor having a structure in which the cavity 13 of the single cylinder 10 is filled with liquid has a high water pressure resistance, and can be applied even in deep water.
【００１５】以上のように第１の実施形態によれば、円
筒型光ファイバ音響センサの単円筒１０の空胴部１３を
密閉する蓋１１にオリフィス１６で形成される開口部を
設け、前述の空胴部１３に液体を満たすことができるよ
うな圧力バランス構造とすることにより、空胴部１３の
静水圧とセンサ外部の静水圧とを一致させることができ
るので、深々度の海中等において使用可能な高耐水圧の
単円筒型光ファイバ音響センサ（ハイドロホン）を得る
ことができる。As described above, according to the first embodiment, the opening formed by the orifice 16 is provided in the lid 11 that seals the cavity 13 of the single cylinder 10 of the cylindrical optical fiber acoustic sensor. Since the hydrostatic pressure of the cavity 13 and the hydrostatic pressure outside the sensor can be matched by using a pressure balance structure that allows the cavity 13 to be filled with a liquid, the hydrostatic pressure can be used in a deep sea or the like. It is possible to obtain a single-cylinder optical fiber acoustic sensor (hydrophone) having a high water pressure resistance.
【００１６】［第２の実施形態］ 図２は本発明による高耐水圧円筒型光ファイバ音響セン
サの第２の実施形態を示す模式断面図である。図２にお
いて、所定の長さ・径を持つ単円筒１０の両端に蓋１
１，１２を取り付け、円筒内が空胴部１３となるように
形成している。また、本実施例では単円筒１０内側面
に、光ファイバ２０（第１の光ファイバ）がコイル状に
巻回され、蓋１２の外側面には、図１の実施形態の場合
と同様に光ファイバ１５（第２の光ファイバ）が巻回さ
れていて、本実施形態の干渉計を構成する構造となって
いる。そして、図１の実施形態の場合と同様に、蓋１１
にはオリフィス１６が設けられているが、その基本的な
構成・構造は第１の実施例で説明したものと同様であ
る。[Second Embodiment] FIG. 2 is a schematic sectional view showing a second embodiment of a high water pressure resistant cylindrical optical fiber acoustic sensor according to the present invention. In FIG. 2, lids 1 are provided at both ends of a single cylinder 10 having a predetermined length and diameter.
1 and 12 are attached to form a cavity 13 inside the cylinder. In this embodiment, an optical fiber 20 (first optical fiber) is wound in a coil shape on the inner surface of the single cylinder 10, and an optical fiber is formed on the outer surface of the lid 12 in the same manner as in the embodiment of FIG. A fiber 15 (second optical fiber) is wound, and has a structure constituting the interferometer of the present embodiment. Then, as in the case of the embodiment of FIG.
Is provided with an orifice 16, the basic configuration and structure of which is the same as that described in the first embodiment.
【００１７】そして、本実施形態では、光ファイバ２０
が単円筒１０の内側面にコイル状に巻回され、光ファイ
バ１５が蓋１２の外側面に巻回されて、本実施形態の干
渉計を構成する構造となっていることを特徴としている
が、その他の構成、作用動作及び効果乃至利点は、前述
の第１の実施形態の場合と同様であるので、詳細な説明
は省略する。In this embodiment, the optical fiber 20
Is wound around the inner surface of the single cylinder 10 in a coil shape, and the optical fiber 15 is wound around the outer surface of the lid 12 to constitute the interferometer of the present embodiment. The other configuration, operation, effects, and advantages are the same as those in the first embodiment, and thus detailed description is omitted.
【００１８】[0018]
【発明の効果】以上のように本発明によれば、１つの円
筒体による単円筒型構造で構成され、円筒体の両端に配
置される蓋を備え、円筒体の側面に沿って巻かれた第１
の光ファイバを備えた円筒型光ファイバ音響センサであ
って、蓋の一方は円筒体の内側と外側との圧力平衡を保
つ開口部を備え、蓋の他方はその側面に第２の光ファイ
バとを備えたものとしたから、部品点数が少なくコンパ
クトで、しかも高感度かつ高耐水圧の円筒型光ファイバ
音響センサを得ることができる。As described above, according to the present invention, a single-cylinder structure having a single cylindrical body is provided, and lids are provided at both ends of the cylindrical body, and are wound along the side surface of the cylindrical body. First
A cylindrical optical fiber acoustic sensor having an optical fiber, one of the lids is provided with an opening for maintaining the pressure balance between the inside and the outside of the cylindrical body, the other of the lid and the second optical fiber on its side. Therefore, it is possible to obtain a compact cylindrical optical fiber acoustic sensor having a small number of parts, a high sensitivity and a high water pressure resistance.
【図１】本発明による高耐水圧円筒型光ファイバ音響セ
ンサの第１の実施形態を示す模式断面図である。FIG. 1 is a schematic cross-sectional view showing a first embodiment of a high water pressure resistant cylindrical optical fiber acoustic sensor according to the present invention.
【図２】本発明による高耐水圧円筒型光ファイバ音響セ
ンサの第２の実施形態を示す模式断面図である。FIG. 2 is a schematic cross-sectional view showing a second embodiment of a high water pressure resistant cylindrical optical fiber acoustic sensor according to the present invention.
【図３】図１の実施形態の干渉計構成を示す模式説明図
である。FIG. 3 is a schematic explanatory view showing a configuration of the interferometer according to the embodiment of FIG. 1;
【図４】図１の実施形態の干渉計構成の周波数特性を示
す線図である。FIG. 4 is a diagram showing frequency characteristics of the interferometer configuration of the embodiment of FIG. 1;
【図５】従来の円筒型光ファイバ音響センサを示す模式
断面図である。FIG. 5 is a schematic sectional view showing a conventional cylindrical optical fiber acoustic sensor.
１ 外円筒 ２ 内円筒 ３ 蓋 ４ 空気室 ５，５ａ 光ファイバ １０ 単円筒 １１，１２ 蓋 １３ 空胴部 １４，１５，２０ 光ファイバ １６ オリフィス １７，１７ａ 光カプラ １８ レーザダイオード（ＬＤ） １９ 光電気変換器（Ｏ／Ｅ） 1 outer cylinder 2 inner cylinder 3 lid 4 air chamber 5,5a optical fiber 10 single cylinder 11,12 lid 13 cavity 14,15,20 optical fiber 16 orifice 17,17a optical coupler 18 laser diode (LD) 19 opto-electric Converter (O / E)
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) G01H 9/00 G01D 5/26 ──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. 7 , DB name) G01H 9/00 G01D 5/26
Claims (1)
され、前記円筒体の両端に配置される蓋を備え、前記円
筒体の側面に沿って巻かれた第１の光ファイバを備えた
円筒型光ファイバ音響センサであって、前記蓋の一方は前記円筒体の内側と外側との圧力平衡を
保つ開口部を備え、 前記蓋の他方はその側面に第２の光ファイバとを備えた
ことを特徴とする高耐水圧円筒型光ファイバ音響セン
サ。 1. A circular structure comprising a single cylindrical structure having one cylindrical body, comprising lids disposed at both ends of the cylindrical body.
A cylindrical optical fiber acoustic sensor comprising a first optical fiber wound along a side surface of a cylindrical body , wherein one of the lids balances pressure between the inside and the outside of the cylindrical body.
A high-pressure-resistant cylindrical optical fiber acoustic sensor , comprising: an opening for retaining; and a second optical fiber on the other side of the lid .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00792896A JP3263897B2 (en) | 1996-01-22 | 1996-01-22 | High water pressure cylindrical optical fiber acoustic sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00792896A JP3263897B2 (en) | 1996-01-22 | 1996-01-22 | High water pressure cylindrical optical fiber acoustic sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09196748A JPH09196748A (en) | 1997-07-31 |
| JP3263897B2 true JP3263897B2 (en) | 2002-03-11 |
Family
ID=11679193
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP00792896A Expired - Fee Related JP3263897B2 (en) | 1996-01-22 | 1996-01-22 | High water pressure cylindrical optical fiber acoustic sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3263897B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5131497B2 (en) * | 2010-09-22 | 2013-01-30 | 防衛省技術研究本部長 | High water pressure optical fiber hydrophone |
| JP5630460B2 (en) * | 2012-05-07 | 2014-11-26 | 防衛省技術研究本部長 | Optical fiber magnetic sensor |
| JP6350239B2 (en) * | 2014-11-21 | 2018-07-04 | 住友電気工業株式会社 | Interference type optical fiber sensor system and interference type optical fiber sensor head |
-
1996
- 1996-01-22 JP JP00792896A patent/JP3263897B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09196748A (en) | 1997-07-31 |
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