JPH08327712A - Optical magnetic-field sensor and method for measuring strength of magnetic field using this sensor - Google Patents
Optical magnetic-field sensor and method for measuring strength of magnetic field using this sensorInfo
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- JPH08327712A JPH08327712A JP7130660A JP13066095A JPH08327712A JP H08327712 A JPH08327712 A JP H08327712A JP 7130660 A JP7130660 A JP 7130660A JP 13066095 A JP13066095 A JP 13066095A JP H08327712 A JPH08327712 A JP H08327712A
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- optical
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Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、磁気光学素子のファラ
デー効果を利用して磁界強度を測定する光磁界センサ及
びそれを用いた磁界強度測定方法に関するものであり、
特に、電力を供給する送電線及び配電線や、受変電設備
(以下、キユービクルという),GIS(GAS INSULATED
SWITCH GEAR) 等の電線の周囲に発生する磁界の強度を
測定することによって電流の大きさを検知するのに用い
て好適な光磁界センサ及びそれを用いた磁界強度測定方
法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical magnetic field sensor for measuring magnetic field strength by utilizing the Faraday effect of a magneto-optical element and a magnetic field strength measuring method using the same.
In particular, power transmission lines and distribution lines, power receiving and transforming facilities (hereinafter referred to as quicles), GIS (GAS INSULATED)
The present invention relates to an optical magnetic field sensor suitable for detecting the magnitude of a current by measuring the strength of a magnetic field generated around an electric wire such as SWITCH GEAR) and a magnetic field strength measuring method using the same.
【0002】[0002]
【従来の技術】これまで、送電線や配電線に流れる電流
の大きさを測定して異常を発見する電流センサや、キユ
ービクル,GIS内において使用されている電流センサ
としては、トランス型のものが用いられてきた。しかし
ながら、トランス型の電流センサは、大型且つ大重量で
あって絶縁性も良くないなど種々の問題点があるため、
最近ではそのような電流センサに代えて光磁界センサを
用いる計画が進められている。2. Description of the Related Art Heretofore, a transformer type current sensor has been used as a current sensor for detecting an abnormality by measuring the magnitude of current flowing through a transmission line or a distribution line, or a current sensor used in a cubicle or GIS. Has been used. However, the transformer-type current sensor has various problems such as large size, heavy weight, and poor insulation.
Recently, a plan to use an optical magnetic field sensor in place of such a current sensor is being advanced.
【0003】光磁界センサを用いる場合には、導体例え
ば送電線に流れる電流によりその周囲に発生する磁界
を、磁気光学材料が有するファラデー効果を利用して測
定し、その測定された磁界からそこに流れている電流値
を求めるようにするが、この場合の特徴としては、高耐
圧,高絶縁性,非接触,小型軽量であって、高圧側に電
源や電気回路が不要なことなどを挙げることができる。When an optical magnetic field sensor is used, a magnetic field generated around a conductor, for example, a current flowing through a transmission line is measured by using the Faraday effect of a magneto-optical material, and the measured magnetic field is applied to the magnetic field. The value of the flowing current is determined, but the characteristics of this case are high breakdown voltage, high insulation, non-contact, small size and light weight, and no need for a power supply or electric circuit on the high voltage side. You can
【0004】このような光磁界センサの基本構成の一例
を図1を用いて説明する。光源1から出射した光は、光
ファイバ2,レンズ3,偏光子4を経て直線偏光となっ
た後、半波長板5を通過して磁気光学素子6に入射す
る。直線偏光となった光は、磁気光学素子6を通過する
とき被測定磁界(以下、磁界と略称する)の強さに応じ
て旋光を受け、検光子7を通過したあと磁界の強さに対
応した強度となってレンズ8で集光され、光ファイバ9
に入射する。An example of the basic configuration of such an optical magnetic field sensor will be described with reference to FIG. The light emitted from the light source 1 passes through the optical fiber 2, the lens 3, and the polarizer 4 to become linearly polarized light, and then passes through the half-wave plate 5 and enters the magneto-optical element 6. The linearly polarized light receives optical rotation according to the strength of the magnetic field to be measured (hereinafter abbreviated as magnetic field) when passing through the magneto-optical element 6, and after passing through the analyzer 7, corresponds to the strength of the magnetic field. The resulting intensity is converged by the lens 8 and the optical fiber 9
Incident on.
【0005】光ファイバ9に入射した光は、光検出器1
0に導かれて光電変換される。その後、信号処理回路1
1においてフィルタにより交流成分と直流成分に分割さ
れ、割り算器により交流電圧成分を直流電圧成分で除算
された値が出力される。このようにして計算された実効
値をもって被測定磁界を表す。ここで、交流電圧成分を
直流電圧成分で除算した値を検出する理由は、光源1の
出射光強度の変動及び光ファイバ2,9の揺れ等による
光量の変動を消去して所望の磁界を検出することができ
るためである。The light incident on the optical fiber 9 is detected by the photodetector 1.
It is led to 0 and photoelectrically converted. After that, the signal processing circuit 1
In 1, the filter is divided into an AC component and a DC component, and a value obtained by dividing the AC voltage component by the DC voltage component is output by the divider. The measured magnetic field is represented by the effective value calculated in this way. Here, the reason why the value obtained by dividing the AC voltage component by the DC voltage component is detected is to detect the desired magnetic field by eliminating the fluctuation of the intensity of the emitted light of the light source 1 and the fluctuation of the light amount due to the shaking of the optical fibers 2 and 9. This is because it can be done.
【0006】上記の構成において、光源1には発光ダイ
オード或いはレーザダイオードを用いることが考えられ
る。しかし、レーザダイオードから出射される光は略直
線偏光であるため、光ファイバ2を通過するときに、光
ファイバ2に生じた応力誘起複屈折により偏光面が変化
してしまい、偏光子4を通過した光の強度が不安定にな
るという問題点がある。従って、光源1には無偏光の光
を出射する発光ダイオードが用いられる。In the above structure, it is possible to use a light emitting diode or a laser diode as the light source 1. However, since the light emitted from the laser diode is substantially linearly polarized light, when passing through the optical fiber 2, the polarization plane changes due to the stress-induced birefringence generated in the optical fiber 2 and passes through the polarizer 4. There is a problem that the intensity of the emitted light becomes unstable. Therefore, a light emitting diode that emits unpolarized light is used as the light source 1.
【0007】また、半波長板5を用いている理由は、偏
光面を45度回転させ、偏光子4と検光子7の相対主軸
角を45度として、光磁界センサの感度を最大とするた
めである。また、磁界と磁気光学材料6を通過する光の
進路とは平行である。尚、この場合には半波長板5と磁
気光学材料6は配置を入れ換えても特性上大きな問題は
ない。The reason why the half-wave plate 5 is used is that the polarization plane is rotated by 45 degrees and the relative principal axis angle between the polarizer 4 and the analyzer 7 is set to 45 degrees to maximize the sensitivity of the optical magnetic field sensor. Is. Further, the magnetic field and the path of the light passing through the magneto-optical material 6 are parallel. In this case, even if the positions of the half-wave plate 5 and the magneto-optical material 6 are exchanged, there is no serious problem in terms of characteristics.
【0008】このような構成の光磁界センサに用いられ
る磁気光学素子6用の材料としては、鉛ガラス,ZnS
e,BGO,BSO等の常磁性材料、又は反磁性材料が
あるが、最近では上記したように送電線,配電線の電流
計測、GIS,キュービクル内の計器用変流器にも光磁
界センサを用いる計画が積極的に進められており、光磁
界センサに対し高感度化、小型化、低価格化が要求され
ているために、量産性が高く磁気感度の高い磁性ガーネ
ットやBi置換の磁性ガーネットを用いた光磁界センサ
の開発が行われるようになってきた。As a material for the magneto-optical element 6 used in the optical magnetic field sensor having such a structure, lead glass and ZnS are used.
There are paramagnetic materials such as e, BGO, BSO, etc., or diamagnetic materials, but recently, as mentioned above, current measurement of power lines and distribution lines, GIS, current transformers for measuring instruments in cubicles are also equipped with optical magnetic field sensors. The use of magnetic garnet is highly promoted, and the optical magnetic field sensor is required to have high sensitivity, small size, and low price. The development of the optical magnetic field sensor using is started.
【0009】ところで、上記の磁気光学素子として、R
IG(Bi: Rare Earth Iron Garnet)等の垂直磁化で多
磁区構造を示す強磁性材料を使用する場合には、RIG
を透過した光は回折現象を起こし、0次光,1次光,〜
n次光と次数に応じて広がっていく(但し、磁界が0の
ときは奇数次光のみ)。これは、磁区が位相格子となる
ためである。By the way, as the above-mentioned magneto-optical element, R
When using a ferromagnetic material such as IG (Bi: Rare Earth Iron Garnet) that exhibits a multi-domain structure with perpendicular magnetization, RIG is used.
The light transmitted through causes a diffraction phenomenon, and the 0th order light, the 1st order light, ~
It spreads according to the nth order light and the order (however, when the magnetic field is 0, only the odd order light). This is because the magnetic domain serves as a phase grating.
【0010】これらの回折光を全て取り込んだ場合に
は、磁界の強さに対する信号処理回路からの出力、即ち
光磁界センサからの出力の直線性は極めて良好なものと
なる(例えば、特開平5−126924号公報参照)。
しかしながら、全ての回折光を取り込むようにするため
には、適切なレンズの選択が必要であり、しかもレンズ
と他の光学部品の精密な配置(以下、アライメントとい
う)によって初めて実現が可能となる。そのため、この
ような光磁界センサは量産性が極めて低いものである。When all of these diffracted lights are taken in, the linearity of the output from the signal processing circuit with respect to the strength of the magnetic field, that is, the output from the optical magnetic field sensor becomes extremely good (see, for example, Japanese Patent Laid-Open No. Hei. -126924).
However, in order to capture all the diffracted light, it is necessary to select an appropriate lens, and moreover, it can be realized only by a precise arrangement of the lens and other optical components (hereinafter referred to as alignment). Therefore, such an optical magnetic field sensor is extremely low in mass productivity.
【0011】他方、全ての回折光を取り込まない場合に
は、光磁界センサを作製するときのアライメントは容易
になり、安価な光磁界センサを実現することが可能とな
るが、逆に、信号処理回路からの出力は直線性が得られ
ないものとなってしまう。その理由を、0次光のみを取
り込んだ場合について、数式を用いて説明する。On the other hand, if not all the diffracted light is taken in, the alignment at the time of manufacturing the optical magnetic field sensor becomes easy, and it becomes possible to realize an inexpensive optical magnetic field sensor. The output from the circuit will not be linear. The reason for this will be described by using mathematical expressions when only the 0th-order light is captured.
【0012】磁気光学素子への入力をIinとした場合、
光検出器10からの出力Io は、 Io =Iin [ cosθ cosφ+ (Ho/Hs) sinθ sinφ sin (ωt)]2 (1) で表される。ここで、θは磁気光学材料のファラデー回
転角、φは二つの偏光子間の相対主軸角、Ho は外部印
加磁界、Hs は飽和磁界、ωは交流磁界の周波数(電流
の周波数)、t は時間である。出力Io は、直流成分I
DCと交流成分IACに分離され、各々、 IDC=Iin [cos2θcos2φ+(Ho2/2Hs2)sin2θsin2φ] (2) IAC=Iin [(Ho/2Hs)sin2θsin2φsin(ωt) −(Ho2/2Hs2)sin2θsin2φcos (2ωt)] (3) で表される。また、信号処理回路内の割り算器により、 I1 =IAC/IDC (4) が求められる。そして、I1 の実効値Cは次式(5)によ
り表される。 C=VAC/VDC (5) ここで、VACはIACの実効値、VDCはIDCの実効値を表
し、各々次式(6)及び(7)により表される。 VDC=Iin [cos2θcos2φ+(Ho2/2Hs2)sin2θsin2φ] (6) VAC=Iin [(Ho2/8Hs2) sin22θ sin22φ +(Ho4/8Hs4)sin2θsin2φ]1/2 (7) 式(5),(6),(7)から明らかなように、この場合には、
Cは外部印加磁界の強さに対して直線的な関係にならな
い。When the input to the magneto-optical element is I in ,
The output I o from the photodetector 10 is represented by I o = I in [cos θ cos φ + (Ho / Hs) sin θ sin φ sin (ωt)] 2 (1). Where θ is the Faraday rotation angle of the magneto-optical material, φ is the relative principal axis angle between the two polarizers, Ho is the externally applied magnetic field, Hs is the saturation magnetic field, ω is the frequency of the alternating magnetic field (current frequency), and t is It's time. The output I o is the direct current component I
Separated into DC and AC components I AC , I DC = I in [cos 2 θcos 2 φ + (Ho 2 / 2Hs 2 ) sin 2 θsin 2 φ] (2) I AC = I in [(Ho / 2Hs) sin2 θsin2 φsin (ωt) − (Ho 2 / 2Hs 2 ) sin 2 θsin 2 φcos (2ωt)] (3). Further, I 1 = I AC / I DC (4) is obtained by the divider in the signal processing circuit. Then, the effective value C of I 1 is expressed by the following equation (5). C = V AC / V DC ( 5) where, V AC is the effective value of I AC, V DC represents the effective value of I DC, represented by each following equation (6) and (7). V DC = I in [cos 2 θcos 2 φ + (Ho 2 / 2Hs 2) sin 2 θsin 2 φ] (6) V AC = I in [(Ho 2 / 8Hs 2) sin 2 2θ sin 2 2φ + (Ho 4 / 8Hs 4) sin 2 θsin 2 φ] 1/2 (7) equation (5), (6), as is clear from (7), in this case,
C does not have a linear relationship with the strength of the externally applied magnetic field.
【0013】[0013]
【発明が解決しようとする課題】上記のように、磁気光
学素子にRIG等の垂直磁化で多磁区構造を示す強磁性
材料を使用した光磁界センサは、高感度ではあるもの
の、磁界の強さに対する信号処理回路からの出力の直線
性を良くしようとすると、光学部品間のアライメントが
難しくなって量産性が低下し、逆に、アライメントの容
易な構成にしようとすると、前記の直線性が悪く、また
位相角も大きくなるなど種々の問題点を有していた。As described above, an optical magnetic field sensor that uses a ferromagnetic material having a multi-domain structure with perpendicular magnetization such as RIG for a magneto-optical element has high sensitivity but strength of magnetic field. If the linearity of the output from the signal processing circuit is improved, the alignment between the optical components becomes difficult and the mass productivity is reduced. On the contrary, if the configuration is easy, the linearity is deteriorated. In addition, there are various problems such as a large phase angle.
【0014】本発明は、このような問題点を解決するた
めになされたものであり、その目的とするところは、高
感度であって、しかも磁界の強さに対する出力の直線性
が良好で高精度が得られ、且つ量産性に優れた光磁界セ
ンサ及びそれを用いた磁界強度測定方法を提供すること
である。The present invention has been made in order to solve such a problem, and an object thereof is to have a high sensitivity and to have a high output linearity with respect to the strength of a magnetic field. An object of the present invention is to provide an optical magnetic field sensor which has high accuracy and is excellent in mass productivity, and a magnetic field strength measuring method using the same.
【0015】[0015]
【課題を解決するための手段及び作用】上記の目的を達
成するために、本発明は、光源と、偏光子と、磁気光学
素子と、検光子と、光検出器と、信号処理回路とを有す
る光磁界センサにおいて、該信号処理回路を該光検出器
の出力値を基本波成分と2次高調波成分に分割し、該2
次高調波成分を該基本波成分で除算する回路で構成す
る。In order to achieve the above object, the present invention comprises a light source, a polarizer, a magneto-optical element, an analyzer, a photodetector and a signal processing circuit. In the optical magnetic field sensor, the signal processing circuit divides the output value of the photodetector into a fundamental wave component and a second harmonic component,
It is composed of a circuit that divides the second harmonic component by the fundamental component.
【0016】また、本発明の光磁界センサによる測定方
法は、磁気光学素子からの光信号を光検出器で光電変換
し、電気信号として求めた値を信号処理回路により基本
波成分と2次高調波成分に分割して、該2次高調波成分
を該基本波成分で除算して得た値から磁界強度を求める
ようにするものである。Further, in the measuring method by the optical magnetic field sensor of the present invention, the optical signal from the magneto-optical element is photoelectrically converted by the photodetector, and the value obtained as the electric signal is converted into the fundamental wave component and the second harmonic by the signal processing circuit. The magnetic field strength is obtained from a value obtained by dividing the second harmonic component by the fundamental component by dividing the second harmonic component.
【0017】[0017]
【実施例】本発明の実施例の具体的な構成とその試験結
果を図2乃至図4を用いて説明する。図2は実際に試作
した本実施例の光磁界センサの構成を示しており、図中
の符号は図1に示されたものと対応させて付けてある。
そこで、先ず、この試作した実施例の構成を具体的に説
明する。EXAMPLE A concrete structure of an example of the present invention and a test result thereof will be described with reference to FIGS. FIG. 2 shows the construction of an actually manufactured optical magnetic field sensor of the present embodiment, and the reference numerals in the figure correspond to those shown in FIG.
Therefore, first, the configuration of this prototype embodiment will be specifically described.
【0018】光源1は波長0.85μmの発光ダイオー
ドであり、光検出器10はSiダイオードである。光フ
ァイバ2,9は夫々マルチモードファイバであり、レン
ズ3,8は夫々セルフォクレンズである。偏光子4及び
検光子7は両方とも偏光ビームスプリッタであり、磁気
光学素子6としては(YbTbBi)3 Fe5 O12を採
用した。また、偏光子4と検光子7を同一表面上に置
き、且つ相対主軸角を45度とするために、半波長板5
が磁気光学素子6の直前に配置されている。The light source 1 is a light emitting diode having a wavelength of 0.85 μm, and the photodetector 10 is a Si diode. The optical fibers 2 and 9 are multimode fibers, and the lenses 3 and 8 are self-focal lenses. Both the polarizer 4 and the analyzer 7 are polarization beam splitters, and (YbTbBi) 3 Fe 5 O 12 is adopted as the magneto-optical element 6. Further, in order to place the polarizer 4 and the analyzer 7 on the same surface and to set the relative principal axis angle to 45 degrees, the half-wave plate 5
Is arranged immediately before the magneto-optical element 6.
【0019】更に、信号処理回路11は二つのバンドパ
スフィルタと割り算器を有しており、光検出器10のS
iダイオードから入力された電気信号を二つのバンドパ
スフィルタにより基本波成分と2次高調波成分とに分離
し、割り算器によって2次高調波成分を基本波成分で除
算した値を出力するようになっている。尚、光ファイバ
9には0次光のみが結合するように、レンズ8と光ファ
イバ9の距離が設定されている。Further, the signal processing circuit 11 has two bandpass filters and a divider, and the S of the photodetector 10 is
The electric signal input from the i diode is separated into a fundamental wave component and a second harmonic component by two band pass filters, and a value obtained by dividing the second harmonic component by the fundamental wave component by a divider is output. Has become. The distance between the lens 8 and the optical fiber 9 is set so that only the 0th order light is coupled to the optical fiber 9.
【0020】次に、上記のような構成にしたことによっ
て、本発明の目的が達成される理由について説明する。
磁気光学素子6からの回折光を全て取り込むことは、既
に述べたように極めて困難であるが、回折光の中で0次
光のみを取り出すことは容易である。0次光のみを意識
的に光検出器10に取り込むには、図において磁気光学
素子6とレンズ8の距離を離すか、本実施例のようにレ
ンズ8と光ファイバ9の距離を調節することで容易に実
現できる。Next, the reason why the object of the present invention is achieved by the above-mentioned structure will be described.
It is extremely difficult to take in all the diffracted light from the magneto-optical element 6 as described above, but it is easy to take out only the 0th-order light among the diffracted lights. In order to consciously capture only the 0th-order light into the photodetector 10, the distance between the magneto-optical element 6 and the lens 8 should be separated in the figure, or the distance between the lens 8 and the optical fiber 9 should be adjusted as in this embodiment. Can be easily achieved with.
【0021】0次光のみを光検出器10に取り込んだと
き、光検出器10からの出力Io と、該出力Io の交流
成分IACは、上記したように夫々式(1)と式(3)で表され
る。その交流成分IACは、次のような周波数ωの基本波
成分IAC1 と周波数2ωの2次高調波成分IAC2 で構成
されている。 IAC1 =Iin [(Ho/2Hs)sin2θsin2φsin(ωt)] (8) IAC2 =Iin [(Ho2/2Hs2)sin2θsin2φcos (2ωt)] (9) 従って、2次高調波成分IAC2 を基本波成分IAC1 で除
した値I2 は、 I2 =IAC2/IAC1 =Ho tanθ tanφ cos(2ωt) / [4Hs sin(ωt)] (10) で表され、I2 の実効値は明らかに外部印加磁界Hoに
比例することが分かる。従って、磁界の強さに対して出
力の直線性が得られる。[0021] When only the 0 order light taken into the light detector 10, an output I o from the photodetector 10, the alternating current component I AC of the output I o, respectively formula as described above (1) wherein It is represented by (3). The AC component I AC is composed of the following fundamental wave component I AC1 of frequency ω and second harmonic component I AC2 of frequency 2ω. I AC1 = I in [(Ho / 2Hs) sin2θsin2φsin (ωt)] (8) I AC2 = I in [(Ho 2 / 2Hs 2 ) sin 2 θsin 2 φcos (2ωt)] (9) Therefore, the second harmonic A value I 2 obtained by dividing the component I AC2 by the fundamental wave component I AC1 is represented by I 2 = I AC2 / I AC1 = Ho tan θ tan φ cos (2ωt) / [4Hs sin (ωt)] (10), and I 2 It can be seen that the effective value of is obviously proportional to the externally applied magnetic field Ho. Therefore, output linearity is obtained with respect to the strength of the magnetic field.
【0022】次に、上記のように構成された本実施例の
試験結果について説明する。本実施例の光磁界センサに
50HZ の交流磁界を0〜700Oe の範囲で変化させ
て印加し、磁界の強さの変化に対する信号処理回路11
からの出力電圧の実効値を調べた結果が図3に示されて
いる。図3中、実線aがその結果であり、信号処理回路
11からの出力、即ち光磁界センサの出力は明らかに直
線的に変化していることが分かる。Next, the test results of this embodiment having the above structure will be described. An AC magnetic field 50H Z to optical magnetic field sensor of the present embodiment is varied within a range of 0~700O e is applied, the signal processing circuit 11 to changes in the intensity of the magnetic field
The result of examining the effective value of the output voltage from is shown in FIG. In FIG. 3, the solid line a is the result, and it can be seen that the output from the signal processing circuit 11, that is, the output of the optical magnetic field sensor obviously changes linearly.
【0023】また、上記の実測結果と、完全な直線とを
比較した比誤差Rが図4に示されている。図4中、実線
aが本実施例の光磁界センサにより得られた比誤差であ
る。この図からも分かるように、本実施例の比誤差は0
%であり、磁界の変化と出力の変化との間に完全な直線
関係が得られている。FIG. 4 shows the ratio error R obtained by comparing the above actual measurement result with a perfect straight line. In FIG. 4, the solid line a is the ratio error obtained by the optical magnetic field sensor of this embodiment. As can be seen from this figure, the ratio error of this embodiment is 0.
%, And a perfect linear relationship is obtained between the change in magnetic field and the change in output.
【0024】このような本実施例の光磁界センサと比較
するために、上記した従来例の信号処理回路、即ち光電
変換されて入力された電気信号をフィルタにより交流成
分と直流成分に分け、割り算器により交流成分を直流成
分で除算した値を出力するようにした信号処理回路を用
いて特性評価を行った。その他の条件は全て本実施例の
場合と同じである。その結果は、図3及び図4に夫々破
線bで示した通りである。直線性は明らかに悪く、比誤
差は磁界強度が35Oe で−2.3%と大きな値であっ
た。In order to make a comparison with the optical magnetic field sensor of this embodiment, the signal processing circuit of the above-mentioned conventional example, that is, the electric signal photoelectrically converted and input is divided into an AC component and a DC component by a filter and divided. The characteristics were evaluated by using a signal processing circuit that outputs a value obtained by dividing the AC component by the DC component by the detector. All other conditions are the same as in this embodiment. The results are as shown by broken lines b in FIGS. 3 and 4, respectively. Linearity clearly worse, the ratio error magnetic field strength was as high as -2.3% at 35o e.
【0025】尚、本発明の光磁界センサの光学部品の配
置構成は図2に示すものに限定されず、図1に示す配置
構成にしてもよい。また、本発明は上記した全ての構成
をユニット化したものに限定されるものではない。更
に、本発明は上記したような送電線等の測定に限らず、
一般の交流磁界の測定に適用できることは言うまでもな
い。The arrangement of the optical components of the optical magnetic field sensor of the present invention is not limited to that shown in FIG. 2, but may be the arrangement shown in FIG. In addition, the present invention is not limited to the above-described configuration having all the units. Furthermore, the present invention is not limited to the above-mentioned measurement of a transmission line and the like,
It goes without saying that it can be applied to general AC magnetic field measurement.
【0026】[0026]
【発明の効果】以上のように、本発明によれば、磁界の
強さに応じて出力を直線的に得ることができ、高感度且
つ高精度な磁界の測定が可能となる。しかも、光検出器
に0次光を取り込むだけで可能であるため、光学部品間
のアライメントが容易であり、量産性に優れ低価格化も
可能である。As described above, according to the present invention, the output can be obtained linearly according to the strength of the magnetic field, and the magnetic field with high sensitivity and high accuracy can be measured. Moreover, since it is possible only by taking in the 0th-order light into the photodetector, alignment between optical components is easy, mass productivity is excellent, and cost reduction is possible.
【図1】本発明の説明に必要な光磁界センサの基本構成
図である。FIG. 1 is a basic configuration diagram of an optical magnetic field sensor necessary for explaining the present invention.
【図2】本発明の実施例である光磁界センサの構成図で
ある。FIG. 2 is a configuration diagram of an optical magnetic field sensor that is an embodiment of the present invention.
【図3】磁界の強度と光磁界センサの出力との関係を示
す図である。FIG. 3 is a diagram showing the relationship between the strength of a magnetic field and the output of an optical magnetic field sensor.
【図4】磁界の強度と比誤差との関係を示す図である。FIG. 4 is a diagram showing a relationship between a magnetic field strength and a ratio error.
1 光源 2,9 光ファイバ 3,8 レンズ 4 偏光子 5 半波長板 6 磁気光学素子 7 検光子 10 光検出器 11 信号処理回路 DESCRIPTION OF SYMBOLS 1 light source 2,9 optical fiber 3,8 lens 4 polarizer 5 half-wave plate 6 magneto-optical element 7 analyzer 10 photodetector 11 signal processing circuit
Claims (2)
光子と、光検出器と、信号処理回路とを有する光磁界セ
ンサにおいて、該信号処理回路が該光検出器の出力値を
基本波成分と2次高調波成分に分割し、該2次高調波成
分を該基本波成分で除算する回路から構成されているこ
とを特徴とする光磁界センサ。1. An optical magnetic field sensor having a light source, a polarizer, a magneto-optical element, an analyzer, a photodetector, and a signal processing circuit, wherein the signal processing circuit outputs the output value of the photodetector. An optical magnetic field sensor comprising a circuit that divides a fundamental wave component and a second-order harmonic component and divides the second-order harmonic component by the fundamental wave component.
いて、該磁気光学素子からの光信号を光検出器で光電変
換し、電気信号として求めた値を信号処理回路により基
本波成分と2次高調波成分に分割して、該2次高調波成
分を該基本波成分で除算して得た値から磁界強度を求め
るようにしたことを特徴とする磁界強度測定方法。2. In a magneto-optical sensor using a magneto-optical element, an optical signal from the magneto-optical element is photoelectrically converted by a photo detector, and a value obtained as an electric signal is converted into a fundamental wave component and a secondary wave by a signal processing circuit. A magnetic field strength measuring method, characterized in that the magnetic field strength is obtained from a value obtained by dividing the second harmonic wave component by the fundamental wave component by dividing the second harmonic wave component.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7130660A JPH08327712A (en) | 1995-05-29 | 1995-05-29 | Optical magnetic-field sensor and method for measuring strength of magnetic field using this sensor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7130660A JPH08327712A (en) | 1995-05-29 | 1995-05-29 | Optical magnetic-field sensor and method for measuring strength of magnetic field using this sensor |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH08327712A true JPH08327712A (en) | 1996-12-13 |
Family
ID=15039566
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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JP7130660A Pending JPH08327712A (en) | 1995-05-29 | 1995-05-29 | Optical magnetic-field sensor and method for measuring strength of magnetic field using this sensor |
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JP (1) | JPH08327712A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105547480A (en) * | 2015-12-24 | 2016-05-04 | 南京理工大学 | High-throughput birefringence interference imaging spectrum device |
-
1995
- 1995-05-29 JP JP7130660A patent/JPH08327712A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105547480A (en) * | 2015-12-24 | 2016-05-04 | 南京理工大学 | High-throughput birefringence interference imaging spectrum device |
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