JP2953290B2 - Faraday effect type optical fiber sensor and current transformer - Google Patents
Faraday effect type optical fiber sensor and current transformerInfo
- Publication number
- JP2953290B2 JP2953290B2 JP6005602A JP560294A JP2953290B2 JP 2953290 B2 JP2953290 B2 JP 2953290B2 JP 6005602 A JP6005602 A JP 6005602A JP 560294 A JP560294 A JP 560294A JP 2953290 B2 JP2953290 B2 JP 2953290B2
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- Prior art keywords
- optical fiber
- current
- effect type
- faraday effect
- type optical
- Prior art date
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- Measuring Magnetic Variables (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
Description
【０００１】[0001]
【産業上の利用分野】この発明は、光ファイバ自体のフ
ァラデー効果を利用したファラデー効果型光ファイバセ
ンサおよびそれを用いた変流器に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Faraday effect type optical fiber sensor utilizing the Faraday effect of an optical fiber itself and a current transformer using the same.
【０００２】[0002]
【従来の技術】光ファラデー素子を用いた従来の電流セ
ンサの構成を図５に示す。図５において１は被測定電流
が流れる電流路、２０はこの電流路１に近接配置した電
流センサである。この電流センサ２０はコリメータ５，
５、偏検光子２，２、λ／２板３および光ファラデー素
子４からなる。この光センサ２０には２本の伝送用光フ
ァイバ６，６を接続する。コリメータ５，５はそれぞれ
光ファイバ６から入射する光および光ファイバ６へ出射
させる光をそれぞれ平行光にする。偏検光子２，２はラ
ンダム光から直線偏光を取り出す。λ／２板３は直線偏
光を４５度回転させ、光ファラデー素子４は電流路１に
流れる被測定電流に比例する磁界を受けて、光の偏波面
を回転させる。偏検光子２，２は光ファラデー素子４に
対する磁界が０の時、電流センサ１１の入力光に対する
出力光の光量変化が最も小さくなる偏光方向に配置して
いる。これにより、電流路１に流れる電流に比例した光
量変化を得て、被測定電流を測定する。2. Description of the Related Art The configuration of a conventional current sensor using an optical Faraday element is shown in FIG. In FIG. 5, reference numeral 1 denotes a current path through which a current to be measured flows, and reference numeral 20 denotes a current sensor arranged close to the current path 1. This current sensor 20 is a collimator 5,
5, a polarization detector 2, 2, a λ / 2 plate 3, and an optical Faraday element 4. The optical sensor 20 is connected to two transmission optical fibers 6 and 6. The collimators 5 and 5 respectively convert the light incident from the optical fiber 6 and the light emitted to the optical fiber 6 into parallel light. The polarization detectors 2 and 2 extract linearly polarized light from random light. The λ / 2 plate 3 rotates the linearly polarized light by 45 degrees, and the optical Faraday element 4 receives a magnetic field proportional to the measured current flowing through the current path 1 and rotates the plane of polarization of light. The polarization analyzers 2, 2 are arranged in the polarization direction in which the change in the amount of output light with respect to the input light of the current sensor 11 is smallest when the magnetic field with respect to the optical Faraday element 4 is 0. Thus, a change in the amount of light proportional to the current flowing through the current path 1 is obtained, and the current to be measured is measured.
【０００３】[0003]
【発明が解決しようとする課題】ところが、このような
光ファラデー素子を用いた電流センサにおいては、被測
定電流が流れる電流路と光ファラデー素子間の距離Ｌと
電流路の発生する磁界の強さＨは、Ｈ＝ＮＩ／Ｌ（Ａ／
ｍ）の関係があるため、距離Ｌが変わると、センサの出
力が変化するため、電流路と電流センサとの位置関係を
精度よく定めなければならず、電流センサの取り付け位
置に制約があった。また、電流センサ自身は、入射側光
ファイバからの光を出射側光ファイバに高精度に戻さな
ければならず、偏検光子、光ファラデー素子およびλ／
２板等の光学部品を高精度に位置決め固定しなければな
らず、製作が困難であった。However, in a current sensor using such an optical Faraday element, the distance L between the current path through which the current to be measured flows and the optical Faraday element and the strength of the magnetic field generated by the current path are described. H is H = NI / L (A /
m), when the distance L changes, the output of the sensor changes. Therefore, the positional relationship between the current path and the current sensor must be accurately determined, and the mounting position of the current sensor is limited. . In addition, the current sensor itself must return the light from the input side optical fiber to the output side optical fiber with high accuracy, and the polarization detector, the optical Faraday element, and the λ /
Optical components such as two plates have to be positioned and fixed with high precision, which has been difficult to manufacture.
【０００４】一方、光ファイバを構成するＳｉＯ2 や多
成分ガラスのファラデー効果を利用して、光ファイバの
入射光と出射光間に生じる偏波面の回転を光量変化等に
変換し検出することによって、磁界または電流を検出す
るファラデー効果型光ファイバセンサが知られている。
このようなセンサは、光ファイバの巻回数を多くするこ
とによって感度を増加させることができ、センサ部と光
伝送路が一体化できるという利点がある。ところが、こ
のような光ファイバセンサは、一般に光ファイバ製造時
の内部歪みや曲げ変形等によって複屈折が生じるため、
偏波面保存性が悪い。たとえば通常の単一モード光ファ
イバは１００°／ｍの直線複屈折を有し、この複屈折に
よる偏波方向の変化はファラデー効果とは独立に生じ、
磁界（電流）感度を上げるためにコイル状に巻回した場
合に、コイル状に巻回することにより生じる複屈折によ
る旋光性がファラデー効果を打ち消すように働くことも
あり、実際には巻回数に比例した感度向上は得られな
い。また、スピンドルファイバと称される低複屈折の光
ファイバでも数°／ｍの直線複屈折を有し、この低複屈
折性の光ファイバでセンサを構成する場合、前記複屈折
による旋光性は温度により変化するため、温度によって
計測誤差が生じ、特別な温度補償を行わなければならな
い。On the other hand, by utilizing the Faraday effect of SiO 2 or multi-component glass constituting the optical fiber, the rotation of the polarization plane generated between the incident light and the output light of the optical fiber is converted into a change in light amount and detected. A Faraday effect type optical fiber sensor for detecting a magnetic field or a current is known.
Such a sensor has the advantage that the sensitivity can be increased by increasing the number of turns of the optical fiber, and the sensor section and the optical transmission path can be integrated. However, such an optical fiber sensor generally generates birefringence due to internal strain or bending deformation during the production of the optical fiber.
Poor polarization preservation. For example, a normal single mode optical fiber has a linear birefringence of 100 ° / m, and the change in the polarization direction due to this birefringence occurs independently of the Faraday effect,
When wound in a coil shape to increase the magnetic field (current) sensitivity, the optical rotation due to birefringence caused by the coil shape may act to cancel the Faraday effect. A proportional increase in sensitivity cannot be obtained. Further, even a low birefringence optical fiber called a spindle fiber has a linear birefringence of several degrees / m, and when a sensor is constituted by this low birefringence optical fiber, the optical rotation due to the birefringence is a temperature. , A measurement error occurs depending on the temperature, and special temperature compensation must be performed.
【０００５】この発明の目的は、複屈折による悪影響を
抑制し高精度な磁界センサまたは電流センサを得ること
のできるファラデー効果型光ファイバセンサおよびそれ
を用いた変流器を提供することにある。An object of the present invention is to provide a Faraday effect type optical fiber sensor capable of suppressing a bad influence by birefringence and obtaining a highly accurate magnetic field sensor or current sensor, and a current transformer using the same.
【０００６】この発明の他の目的は、温度による複屈折
（旋光性）の変化を抑えて、特別な温度補償を不要とし
たファラデー効果型光ファイバセンサおよびそれを用い
た変流器を提供することにある。Another object of the present invention is to provide a Faraday effect type optical fiber sensor which suppresses a change in birefringence (optical rotation) due to temperature and does not require special temperature compensation, and a current transformer using the same. It is in.
【０００７】[0007]
【課題を解決するための手段】この発明の請求項１に係
るファラデー効果型光ファイバセンサは、光ファイバの
一端から偏光光を入射させ、他端から出射する光の偏波
面の回転を検出するファラデー効果型光ファイバセンサ
において、一定長を有する単一モードの光ファイバに右
旋捩じり区間および左旋捩じり区間を設け、距離当たり
の捩じり回数をほぼ等しくするとともに、右旋捩じり区
間の累積捩じり回数と左旋捩じり区間の累積捩じり回数
を略等しくしたことを特徴とする。According to a first aspect of the present invention, there is provided a Faraday effect type optical fiber sensor which receives polarized light from one end of an optical fiber and detects rotation of the plane of polarization of light emitted from the other end. In a Faraday effect type optical fiber sensor, a single-mode optical fiber having a fixed length is provided with a right-hand twist section and a left-hand twist section to substantially equalize the number of twists per distance, and The present invention is characterized in that the cumulative number of twists in the torsion section is substantially equal to the cumulative number of twists in the left-handed torsion section.
【０００８】請求項２に係るファラデー効果型光ファイ
バセンサは、請求項１記載の捩じった状態の光ファイバ
がチューブ内に収納したことを特徴とする。A Faraday effect type optical fiber sensor according to a second aspect is characterized in that the twisted optical fiber according to the first aspect is housed in a tube.
【０００９】請求項３に係る変流器は、請求項２記載の
捩じった状態の光ファイバを収納したチューブをボビン
に巻回するとともに、そのボビンに被測定電流の流れる
電流路を挿通させたことを特徴とする。According to a third aspect of the present invention, the tube accommodating the twisted optical fiber according to the second aspect is wound around a bobbin, and a current path through which a current to be measured flows is inserted into the bobbin. It is characterized by having made it.
【００１０】[0010]
【作用】請求項１に係るファラデー効果型光ファイバセ
ンサは一定長を有する単一モードの光ファイバの一端か
ら入射する光の偏波面に対する他端から出射する光の偏
波面の回転を検出することによって光ファイバに与えら
れる磁界または磁界を発生する電流の測定に用いられる
が、前記光ファイバには右旋捩じり区間および左旋捩じ
り区間が設けられ、距離当たりの捩じり回数がほぼ等し
く右旋捩じり区間の累積捩じり回数と左旋捩じり区間の
累積捩じり回数が略等しく構成されている。たとえば、
中央が固定されて、その軸方向の前後で回数が等しく且
つ方向が逆の捩じりが与えられている。このように単一
モードの光ファイバに捩じりを与えることによって、複
屈折に規則性が与えられ、偏波面保存性が高まる。ま
た、光ファイバの温度により生じる複屈折（旋光性）は
相反性があるが、この発明では距離当たりの捩じり回数
が略等しく、且つ光ファイバの右旋捩じり区間と左旋捩
じり区間のそれぞれの累積捩じり回数がほぼ等しいた
め、光ファイバの入射端と出射端間では温度により生じ
る複屈折（旋光性）が打ち消され、温度変化が偏波面の
回転検出結果に影響を与えない。According to a first aspect of the present invention, there is provided a Faraday effect type optical fiber sensor for detecting a rotation of a plane of polarization of light emitted from the other end with respect to a plane of polarization of light incident from one end of a single mode optical fiber having a fixed length. The optical fiber is provided with a right-handed twist section and a left-handed twist section, and the number of twists per distance is substantially equal. The cumulative number of twists in the right-handed torsion section and the cumulative number of twists in the left-handed torsion section are substantially equal. For example,
The center is fixed, and the torsion is given the same number of times before and after the axial direction and in the opposite direction. By imparting a twist to the single-mode optical fiber in this way, birefringence is given regularity and polarization plane preservation is enhanced. Further, although birefringence (rotation) generated by the temperature of the optical fiber is reciprocal, in the present invention, the number of twists per distance is substantially equal, and the right-handed twist section and the left-handed twist of the optical fiber are used. Since the cumulative number of twists in each section is almost equal, birefringence (rotation) caused by temperature is canceled between the input end and the output end of the optical fiber, and the temperature change affects the rotation detection result of the polarization plane. Absent.
【００１１】請求項２に係るファラデー効果型光ファイ
バセンサでは、捩じった状態の光ファイバがチューブ内
に収納されているため、捩じりによる光ファイバの広が
りが抑制され、チューブ内において光ファイバの捩じり
状態が安定に保持される。In the Faraday effect type optical fiber sensor according to the second aspect, since the optical fiber in the twisted state is housed in the tube, the expansion of the optical fiber due to the twisting is suppressed, and the optical fiber in the tube is reduced. The twisted state of the fiber is stably maintained.
【００１２】ここで、前記チューブの内径をＲｇ、捩じ
りをτとして、両者の関係を参考として(1) 式に示す。Here, the inner diameter of the tube is represented by Rg, and the torsion is represented by τ.
【００１３】 Ｒｇ2 −（０．６８Ｒｇ／√τ）＋（１／τ2 ）≧０ …(1) 上式においてτは単位長さ（１ｍ）当たりの捩じり回数
であり、たとえばτ＝５０の時、チューブの内径Ｒｇは
Ｒｇ＜０．２７である。チューブの内径は保護被覆の外
径より大きくなければならないため、たとえば保護被覆
の外径が２２０μｍの光ファイバーを用いて、捩じり回
数τをτ＜５０とすれば、チューブの内径は０．５ｍｍ
以上が適当となり、またボビン等に巻回する際の作業性
およびチューブに与える影響を考えて１３ｍｍ以下が適
当な値となる。Rg 2 − (0.68Rg / √τ) + (1 / τ 2 ) ≧ 0 (1) In the above equation, τ is the number of twists per unit length (1 m), for example, τ = At 50, the inner diameter Rg of the tube is Rg <0.27. Since the inner diameter of the tube must be larger than the outer diameter of the protective coating, for example, using an optical fiber having the outer diameter of the protective coating of 220 μm and setting the number of twists τ to τ <50, the inner diameter of the tube is 0.5 mm
The above is appropriate, and an appropriate value is 13 mm or less in consideration of the workability when wound around a bobbin and the influence on the tube.
【００１４】請求項３に係る変流器では、前記チューブ
がボビンに巻回されて、そのボビンに被測定電流の流れ
る電流路が挿通されている。このように捩じった状態の
光ファイバが収納されたチューブがボビンに巻回されて
いるため、被測定電流の流れる電流路の熱および振動等
を直接受けず、また光ファイバの変位による複屈折が抑
えられ、安定した状態で電流測定を行うことができる。In the current transformer according to a third aspect, the tube is wound around a bobbin, and a current path through which a current to be measured flows is inserted through the bobbin. Since the tube containing the twisted optical fiber is wound around the bobbin, the tube does not directly receive the heat and vibration of the current path through which the current to be measured flows. Refraction is suppressed, and current measurement can be performed in a stable state.
【００１５】ここで、ボビンの径をＲｈ、保護被覆の施
された光ファイバの外形をＲｐ、複屈折をβとして、こ
れらの関係を参考として(2) 式に示す。Here, assuming that the diameter of the bobbin is Rh, the outer shape of the optical fiber with the protective coating is Rp, and the birefringence is β, the relationship is shown in equation (2).
【００１６】 β＝（０．８５／λ）（Ｒｐ／Ｒｈ）2 〔ｒａｄ／ｍ〕 …(2) 上式においてλは入射光の光の波長である。Β = (0.85 / λ) (Rp / Rh) 2 [rad / m] (2) In the above equation, λ is the wavelength of the incident light.
【００１７】また、光ファイバを捩じることにより生じ
る複屈折と誤差εとの関係を参考として(3) 式に示す。The relationship between the birefringence caused by twisting the optical fiber and the error ε is shown in equation (3).
【００１８】 ε2 ≒｛（０．８５／λ）（Ｒｐ／Ｒｈ）2 ｝2 ／（ｇτ）2 …(3) 上式においてｇは光ファイバの材料により定まる値であ
る。Ε 2 ≒ ｛(0.85 / λ) (Rp / Rh) 2 ｝ 2 / (gτ) 2 (3) In the above equation, g is a value determined by the material of the optical fiber.
【００１９】変流器に要求される精度として、ε2 ＜１
０-4の精度とする場合、λ＝７８０ｎｍ、Ｒｐ＝２２０
μｍとすれば、τ＝５０の時Ｒｈ≧１０ｃｍが目安とな
る。As the accuracy required for the current transformer, ε 2 <1
When the accuracy is 0 -4 , λ = 780 nm, Rp = 220
If μm, Rh ≧ 10 cm when τ = 50 is a standard.
【００２０】しかし、このボビンの径は他の装置（例え
ば増幅器等）との組み合わせにより、１０ｃｍより小さ
くすることは可能である。However, the diameter of the bobbin can be made smaller than 10 cm by combination with another device (for example, an amplifier or the like).
【００２１】[0021]
【実施例】この発明の実施例であるファラデー効果型光
ファイバセンサおよびそれを用いた変流器の構成を図１
〜図４を基に説明する。FIG. 1 shows a configuration of a Faraday effect type optical fiber sensor according to an embodiment of the present invention and a current transformer using the same.
This will be described with reference to FIGS.
【００２２】図１は捩じりを与える前の展開状態の光フ
ァイバを示す。図１おいて１１は長さ１０ｍの単一モー
ド光ファイバであり、その中央に固定具１０を取り付
け、両端にコネクタ７，７を設けている。その後、両端
のコネクタ７，７を固定したまま固定具１０を光ファイ
バの軸回りに回転させることにより、図における固定具
の左側と右側とで、光ファイバ１１に与える捩じり方向
を逆の関係にするとともに、その捩じり回数を等しくす
る。ここでは捩じり回数τをτ≦５０（回／ｍ）とす
る。FIG. 1 shows the optical fiber in an unfolded state before being twisted. In FIG. 1, reference numeral 11 denotes a single-mode optical fiber having a length of 10 m. A fixture 10 is attached to the center of the single-mode optical fiber, and connectors 7 are provided at both ends. Thereafter, the fixture 10 is rotated around the optical fiber axis while the connectors 7 and 7 at both ends are fixed, so that the twist direction given to the optical fiber 11 is reversed between the left and right sides of the fixture in the figure. And the number of twists is equal. Here, the number of twists τ is set to τ ≦ 50 (times / m).
【００２３】図２は、図１に示した光ファイバ１１をチ
ューブ内に挿入した状態を示す断面図である。図２にお
いて光ファイバ１１は、たとえば直径５μｍのコア１２
と直径１２５μｍのクラッドおよび直径２２０μｍの保
護被覆１４からなる。また、同図において９はチューブ
であり、その内径は０．５ｍｍ以上１３ｍｍ以下であ
る。FIG. 2 is a sectional view showing a state where the optical fiber 11 shown in FIG. 1 is inserted into a tube. In FIG. 2, an optical fiber 11 has a core 12 having a diameter of 5 μm, for example.
And a cladding having a diameter of 125 μm and a protective coating 14 having a diameter of 220 μm. In the same figure, reference numeral 9 denotes a tube having an inner diameter of 0.5 mm or more and 13 mm or less.
【００２４】図３はチューブ９内に光ファイバ１１を挿
入するとともに、捩じりを与えた様子を示す部分斜視図
である。このようにチューブ９内に捩じりを与えた光フ
ァイバ１１を保持させたことにより、光ファイバ１１の
広がりを抑えるとともに、その捩じり状態を安定に保つ
ことができる。FIG. 3 is a partial perspective view showing a state where the optical fiber 11 is inserted into the tube 9 and twisted. By holding the twisted optical fiber 11 in the tube 9 as described above, the spread of the optical fiber 11 can be suppressed, and the twisted state can be stably maintained.
【００２５】図４は図３に示した、光ファイバを保持す
るチューブをボビンに巻回してなる変流器の構成を示す
斜視図である。図４において８はボビンであり、図に示
すようにチューブ９をボビン８に所定回数巻回するとと
もに、ボビン８に、被測定電流の流れる電流路１を挿通
させている。このような構成で、コネクタ７，７に対
し、偏波面の回転量を検出する装置を接続し、その偏波
面の回転量から電流測定を行うことができる。具体的に
はＬＤ（レーザダイオード）またはＬＥＤ（発光ダイオ
ード）の光を偏光子を通して一方のコネクタ７へ入射さ
せ、他方のコネクタ７から出射する光を検光子を通して
光検出器で受光するようにする。その際、ＬＤまたはＬ
ＥＤを強度変調させて、光検出器の出力から直流成分に
対する交流成分の比を求めることによって、光ファイバ
等による光損失等の変動による光強度変化の影響を打ち
消すようにする。FIG. 4 is a perspective view showing the structure of the current transformer shown in FIG. 3 in which the tube holding the optical fiber is wound around a bobbin. In FIG. 4, reference numeral 8 denotes a bobbin. As shown in FIG. 4, a tube 9 is wound around the bobbin 8 a predetermined number of times, and the current path 1 through which the current to be measured flows is inserted through the bobbin 8. With such a configuration, a device for detecting the amount of rotation of the plane of polarization can be connected to the connectors 7, 7, and the current can be measured from the amount of rotation of the plane of polarization. Specifically, light from an LD (laser diode) or LED (light emitting diode) is made incident on one connector 7 through a polarizer, and light emitted from the other connector 7 is received by a photodetector through an analyzer. . At that time, LD or L
The intensity of the ED is modulated, and the ratio of the AC component to the DC component is obtained from the output of the photodetector, thereby canceling the influence of the light intensity change due to the fluctuation of the optical loss due to the optical fiber or the like.
【００２６】なお、ボビン８に対しチューブ９を多層巻
きして、ボビン８に対する巻き幅を狭くすることも可能
である。また、ボビン８にチューブ９を巻回した状態
で、全体を樹脂モールドし、ボビン全体を緩衝材で保持
して、耐振性を持たせてもよい。It is also possible to wind the tube 9 around the bobbin 8 in a multilayer manner so as to reduce the winding width around the bobbin 8. Alternatively, the entirety of the bobbin 8 may be resin-molded in a state where the tube 9 is wound around the bobbin 8, and the entire bobbin may be held by a cushioning material to provide vibration resistance.
【００２７】[0027]
【発明の効果】この発明の請求項１に係るファラデー効
果型光ファイバセンサによれば、偏波面保存性が高く、
しかも温度依存性を極めて小さくすることができ、高精
度な磁界または電流センサとして用いることができる。According to the Faraday effect type optical fiber sensor according to the first aspect of the present invention, the polarization preservation is high,
In addition, the temperature dependency can be made extremely small, and it can be used as a highly accurate magnetic field or current sensor.
【００２８】請求項２に係るファラデー効果型光ファイ
バセンサによれば、光ファイバの捩じり状態を安定に保
持したまま、ボビン等に容易に巻回することが可能とな
る。According to the Faraday effect type optical fiber sensor according to the second aspect, it is possible to easily wind the optical fiber around a bobbin or the like while keeping the twisted state of the optical fiber stably.
【００２９】請求項３に係る変流器では、構造が単純で
あるため製作が容易となり、しかも被測定電流の流れる
電流路に対し周回するため、取り付け位置に制約を受け
ず、また他相誘導を受けない、という効果を奏する。According to the third aspect of the present invention, the current transformer has a simple structure and is easy to manufacture. In addition, since the current transformer circulates around the current path through which the current to be measured flows, there is no restriction on the mounting position and the other phase induction This has the effect of not receiving it.
【図１】この発明の実施例に係るファラデー効果型光フ
ァイバセンサの捩じりを与える前の光ファイバの構成を
示す図である。FIG. 1 is a diagram showing a configuration of an optical fiber of a Faraday effect type optical fiber sensor according to an embodiment of the present invention before a twist is applied.
【図２】チューブ内に挿入した光ファイバの構造を示す
断面図である。FIG. 2 is a cross-sectional view showing a structure of an optical fiber inserted into a tube.
【図３】チューブ内に捩じりを与えた光ファイバを保持
した状態を示す部分斜視図である。FIG. 3 is a partial perspective view showing a state in which a twisted optical fiber is held in a tube.
【図４】この発明の実施例に係る変流器の構成を示す斜
視図である。FIG. 4 is a perspective view showing a configuration of a current transformer according to the embodiment of the present invention.
【図５】従来の電流センサの構成を示す図である。FIG. 5 is a diagram illustrating a configuration of a conventional current sensor.
１−電流路 ２−偏検光子 ３−λ／２板 ４−光ファラデー素子 ５−コリメータ ６−伝送用光ファイバ ７−コネクタ ８−ボビン ９−チューブ １０−固定部 １１−単一モード光ファイバ １２−コア １３−クラッド １４−保護被覆 DESCRIPTION OF SYMBOLS 1-Current path 2-polarizer 3-lambda / 2 plate 4-optical Faraday element 5-collimator 6-transmission optical fiber 7-connector 8-bobbin 9-tube 10-fixing part 11-single-mode optical fiber 12 -Core 13-cladding 14-protective coating
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭63−263470（ＪＰ，Ａ) 特開 平６−18567（ＪＰ，Ａ) 特開 平５−196708（ＪＰ，Ａ) 特開 昭61−286244（ＪＰ，Ａ) 特開 平５−11152（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) G01R 33/032 G01R 15/24 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-263470 (JP, A) JP-A-6-18567 (JP, A) JP-A-5-196708 (JP, A) JP-A 61-263 286244 (JP, A) JP-A-5-11152 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) G01R 33/032 G01R 15/24
Claims (3)
他端から出射する光の偏波面の回転を検出するファラデ
ー効果型光ファイバセンサにおいて、 一定長を有する単一モードの光ファイバに右旋捩じり区
間および左旋捩じり区間を設け、距離当たりの捩じり回
数をほぼ等しくするとともに、右旋捩じり区間の累積捩
じり回数と左旋捩じり区間の累積捩じり回数を略等しく
したことを特徴とするファラデー効果型光ファイバセン
サ。A polarized light is incident from one end of an optical fiber,
In a Faraday effect type optical fiber sensor for detecting the rotation of the polarization plane of light emitted from the other end, a single mode optical fiber having a fixed length is provided with a right-handed twist section and a left-handed twist section, and Faraday effect type optical fiber sensor characterized in that the number of torsions in the right-handed torsion section and the cumulative number of torsions in the left-handed torsion section are substantially equal to each other. .
内に収納されてなる請求項１記載のファラデー効果型光
ファイバセンサ。2. The Faraday effect type optical fiber sensor according to claim 1, wherein said twisted optical fiber is housed in a tube.
るとともに、そのボビンに被測定電流の流れる電流路を
挿通させたことを特徴とする変流器。3. A current transformer, wherein the tube according to claim 2 is wound around a bobbin, and a current path through which a current to be measured flows is inserted through the bobbin.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6005602A JP2953290B2 (en) | 1994-01-24 | 1994-01-24 | Faraday effect type optical fiber sensor and current transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6005602A JP2953290B2 (en) | 1994-01-24 | 1994-01-24 | Faraday effect type optical fiber sensor and current transformer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07209398A JPH07209398A (en) | 1995-08-11 |
| JP2953290B2 true JP2953290B2 (en) | 1999-09-27 |
Family
ID=11615775
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6005602A Expired - Fee Related JP2953290B2 (en) | 1994-01-24 | 1994-01-24 | Faraday effect type optical fiber sensor and current transformer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2953290B2 (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6563589B1 (en) | 1996-04-19 | 2003-05-13 | Kvh Industries, Inc. | Reduced minimum configuration fiber optic current sensor |
| US6539134B1 (en) | 1999-02-11 | 2003-03-25 | Kvh Industries, Inc. | Polarization transformer |
| US6891622B2 (en) | 1999-02-11 | 2005-05-10 | Kvh Industries, Inc. | Current sensor |
| US6370289B1 (en) | 2000-01-12 | 2002-04-09 | Kvh Industries, Inc. | Apparatus and method for electronic RIN reduction in fiber-optic sensors |
| EP1261880B1 (en) * | 2000-02-28 | 2004-04-21 | KVH Industries, Inc. | Faraday-effect current sensor with improved vibration response |
| AU2001280542A1 (en) | 2000-07-13 | 2002-01-30 | Kvh Industries, Inc. | Method for controlling fiber optic sensor scale factor |
| AU2002217751A1 (en) | 2000-08-02 | 2002-03-26 | Kvh Industries, Inc. | Decreasing the effects of linear birefringence in a fiber-optic sensor by use of berry's topological phase |
| WO2002010813A2 (en) | 2000-08-02 | 2002-02-07 | Kvh Industries, Inc. | Reduction of linear birefringence in circular-core single-mode fiber |
| US6836334B2 (en) | 2001-10-31 | 2004-12-28 | Kvh Industries, Inc. | Angle random walk (ARW) noise reduction in fiber optic sensors using an optical amplifier |
| US6763153B2 (en) | 2002-04-17 | 2004-07-13 | Kvh Industries, Inc. | Apparatus and method for electronic RIN reduction in fiber-optic sensors utilizing filter with group delay |
| CN113252961A (en) * | 2021-04-27 | 2021-08-13 | 哈尔滨工业大学 | All-fiber current transformer sensing head for inhibiting linear birefringence |
-
1994
- 1994-01-24 JP JP6005602A patent/JP2953290B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07209398A (en) | 1995-08-11 |
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