JP6603634B2 - Electric field sensor - Google Patents
Electric field sensor Download PDFInfo
- Publication number
- JP6603634B2 JP6603634B2 JP2016163427A JP2016163427A JP6603634B2 JP 6603634 B2 JP6603634 B2 JP 6603634B2 JP 2016163427 A JP2016163427 A JP 2016163427A JP 2016163427 A JP2016163427 A JP 2016163427A JP 6603634 B2 JP6603634 B2 JP 6603634B2
- Authority
- JP
- Japan
- Prior art keywords
- electric field
- region
- electro
- insulating substrate
- field 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.)
- Active
Links
Description
本発明は、電気光学結晶と光を利用して電界を検出する電界ゼンサに関する。 The present invention relates to an electric field sensor that detects an electric field by using an electro-optic crystal and light.
電界センサの一例として、電気光学結晶を用いたセンサが知られている（例えば非特許文献１）。非特許文献１の電界センサは、センサ感度を最大化する目的で、１／４波長板と１／２波長板の双方を備える。また、特許文献１の電界センサは、１／２波長板を用いずに、１／４波長板のみを用いてセンサ感度を最大化している。 As an example of an electric field sensor, a sensor using an electro-optic crystal is known (for example, Non-Patent Document 1). The electric field sensor of Non-Patent Document 1 includes both a quarter-wave plate and a half-wave plate for the purpose of maximizing sensor sensitivity. Moreover, the electric field sensor of Patent Document 1 maximizes the sensor sensitivity by using only a quarter wavelength plate without using a half wavelength plate.
特許文献１に記載された電界センサは、１／２波長板が不要という利点がある一方、電気光学結晶を、他の光学素子に対して傾けて配置する必要がある。しかし、その具体的な配置方法については開示されていない。よって、実用的な電界センサを容易に製造することが出来ないという課題がある。 The electric field sensor described in Patent Document 1 has an advantage that a half-wave plate is not required, while the electro-optic crystal needs to be disposed with an inclination relative to other optical elements. However, the specific arrangement method is not disclosed. Therefore, there is a problem that a practical electric field sensor cannot be easily manufactured.
本発明は、この課題に鑑みてなされたものであり、容易に製造することが可能な電界センサを提供することを目的とする。 The present invention has been made in view of this problem, and an object thereof is to provide an electric field sensor that can be easily manufactured.
本実施の形態の一態様に係る電界センサは、絶縁基板と、前記絶縁基板の上に配置され、偏光の状態が保持されて伝搬されたプローブ光を楕円偏光の第１光に変換する１／４波長板と、前記絶縁基板の上に配置され、前記絶縁基板に対して傾斜している座面を持つ台座と、前記座面の上に配置され、入射して透過する前記第１光を、受けた電磁波の瞬時電界に対応して偏光変化させた第２光として出射する電気光学結晶と、前記第２光の中から、瞬時電界に対応して偏光変化させた偏光成分を取り出す偏光分離部とを備え、前記絶縁基板は、平面視において幅の広い第１領域と、前記第１領域よりも幅の狭い第２領域とを備え、前記第１領域と前記第２領域は、前記第１領域から前記第２領域に向けて徐々に幅が狭くなるテーパ部で連結し、前記台座と前記電気光学結晶とは、前記第２領域の先端部分に配置され、前記１／４波長板と前記偏光分離部とは、前記第１領域に配置されることを要旨とする。 An electric field sensor according to an aspect of the present embodiment includes an insulating substrate, and a probe light which is disposed on the insulating substrate and which is propagated while maintaining a polarization state is converted into first elliptically polarized light. A four-wavelength plate; a pedestal having a seating surface that is disposed on the insulating substrate and inclined with respect to the insulating substrate; and the first light that is disposed on the seating surface and is incident and transmitted therethrough. , An electro-optic crystal that emits as a second light whose polarization is changed in response to the instantaneous electric field of the received electromagnetic wave, and a polarization separation that extracts a polarization component whose polarization is changed in response to the instantaneous electric field from the second light The insulating substrate includes a first region that is wider in plan view and a second region that is narrower than the first region, wherein the first region and the second region are the first region and the second region, respectively. It is connected by a taper that gradually decreases in width from one region toward the second region, Serial pedestal and said The electro-optic crystal, wherein disposed at the distal end portion of the second region, the A and the quarter-wave plate the polarization separating part, is summarized as Rukoto disposed in the first region.
本発明によれば、容易に製造することが可能な電界センサを提供することができる。 According to the present invention, an electric field sensor that can be easily manufactured can be provided.
以下、本発明の実施形態について図面を用いて説明する。複数の図面中同一のものに
は同じ参照符号を付し、説明は繰り返さない。
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same components in a plurality of drawings, and the description will not be repeated.
〔第１の実施の形態〕
図１に、第１の実施の形態に係る電界センサ１の主要部の模式的平面図を示す。電界センサ１の主要部は、絶縁基板１０、第１コリメータ１１、鏡１２、鏡１３、偏光分離部１４、１／４波長板１５、電気光学結晶１６、台座１７、鏡１８、及び第２コリメータ１９を備える。
[First Embodiment]
In FIG. 1, the typical top view of the principal part of the electric field sensor 1 which concerns on 1st Embodiment is shown. The main parts of the electric field sensor 1 include an insulating substrate 10, a first collimator 11, a mirror 12, a mirror 13, a polarization separation unit 14, a quarter wavelength plate 15, an electro-optic crystal 16, a pedestal 17, a mirror 18, and a second collimator. 19 is provided.
絶縁基板１０は、平面視において幅の広い第１領域１０ａと、第１領域１０ａよりも幅の狭い第２領域１０ｂとを備え、第１領域１０ａと第２領域１０ｂは、第１領域１０ａから第２領域１０ｂに向けて徐々に幅が狭くなるテーパ部１０ｃで連結した１枚の基板である。絶縁基板１０はｘ−ｚ面を構成し、その上に光学部品が配置される。 The insulating substrate 10 includes a first region 10a that is wider in plan view and a second region 10b that is narrower than the first region 10a. The first region 10a and the second region 10b are separated from the first region 10a. It is one board | substrate connected with the taper part 10c which becomes narrow gradually toward the 2nd area | region 10b. The insulating substrate 10 constitutes an xz plane, on which optical components are arranged.
絶縁基板１０は、被測定電波の反射を減らすため、誘電率の低い材料で構成するのが好ましい。例えばテフロン（登録商標）、デルリン等の材料が好適である。 The insulating substrate 10 is preferably made of a material having a low dielectric constant in order to reduce reflection of the radio wave to be measured. For example, materials such as Teflon (registered trademark) and Delrin are suitable.
図示していないレーザなどの光源から出射したプローブ光は、直線偏光として偏波保持ファイバー２０内を伝搬した後に、絶縁基板１０の第１領域１０ａの上に配置された第１コリメータ１１に入射する。第１コリメータ１１は、入射したプローブ光を平行光にして絶縁基板１０上の空間に出射する。 Probe light emitted from a light source such as a laser (not shown) propagates through the polarization maintaining fiber 20 as linearly polarized light and then enters the first collimator 11 disposed on the first region 10a of the insulating substrate 10. . The first collimator 11 converts the incident probe light into parallel light and emits it into the space on the insulating substrate 10.
空間に出射された平行光の直線偏光は、鏡１２と鏡１３とで反射された後に、偏光分離部１４に入射する。直線偏光のプローブ光は、偏光分離部１４を透過して１／４波長板１５に入射する。 The linearly polarized light of the parallel light emitted to the space is reflected by the mirror 12 and the mirror 13 and then enters the polarization separation unit 14. The linearly-polarized probe light passes through the polarization separation unit 14 and enters the quarter-wave plate 15.
１／４波長板１５は、直線偏光のプローブ光を、楕円偏光のプローブ光に変換し、絶縁基板１０の第２領域１０ｂの先端部分（ｚ軸方向先端部）に配置された電気光学結晶１６に入射させる。 The quarter-wave plate 15 converts linearly polarized probe light into elliptically polarized probe light, and the electro-optic crystal 16 disposed at the tip portion (z-axis direction tip portion) of the second region 10b of the insulating substrate 10. To enter.
ここで、図２を参照する。図２は、絶縁基板１０の第２領域１０ｂの先端部分から、電気光学結晶１６の方向を見た電界センサ１の模式的構造図である。太い破線で示す円Ｃ１と円Ｃ２は、電界センサ１の主要部を収容する筐体の断面形状を表す。 Reference is now made to FIG. FIG. 2 is a schematic structural diagram of the electric field sensor 1 when the direction of the electro-optic crystal 16 is viewed from the tip portion of the second region 10b of the insulating substrate 10. Circles C <b> 1 and C <b> 2 indicated by thick broken lines represent the cross-sectional shape of the housing that houses the main part of the electric field sensor 1.
電気光学結晶１６は、台座１７の上に配置される。台座１７は、絶縁基板１０（ｘ−ｚ面）に対して傾斜している座面１７ａを持ち、絶縁基板１０の先端部分の第２領域１０ｂの上に配置される。電気光学結晶１６の１／４波長板１５と反対側の端面には誘電体鏡１６ａが取り付けられている。 The electro-optic crystal 16 is disposed on the pedestal 17. The pedestal 17 has a seat surface 17 a that is inclined with respect to the insulating substrate 10 (xz plane), and is disposed on the second region 10 b at the tip portion of the insulating substrate 10. A dielectric mirror 16 a is attached to the end surface of the electro-optic crystal 16 opposite to the quarter-wave plate 15.
このように台座１７の傾斜している座面１７ａの上に電気光学結晶１６を配置することで、プローブ光に対する電気光学結晶１６の角度を正確に設定することができる。座面１７ａの傾斜は、絶縁基板１０に対して例えばφ=-22.5°である。ここでマイナスは、図２に示したｘ−ｙ面内での時計回りの回転角を表す。この角度について詳しくは後述する。 Thus, by arranging the electro-optic crystal 16 on the inclined seating surface 17a of the pedestal 17, the angle of the electro-optic crystal 16 with respect to the probe light can be set accurately. The inclination of the seating surface 17a is, for example, φ = −22.5 ° with respect to the insulating substrate 10. Here, minus represents the clockwise rotation angle in the xy plane shown in FIG. This angle will be described in detail later.
電気光学結晶１６に入射したプローブ光は、結晶内を伝搬して誘電体鏡１６ａで反射され、再び入射面から空間に出射する。電気光学結晶１６内を伝搬しているプローブ光は、電気光学結晶１６内を伝搬している測定対象の電波の電界に応じて偏光変調を受ける。 The probe light incident on the electro-optic crystal 16 propagates in the crystal, is reflected by the dielectric mirror 16a, and is emitted from the incident surface to the space again. The probe light propagating through the electro-optic crystal 16 undergoes polarization modulation according to the electric field of the radio wave to be measured propagating through the electro-optic crystal 16.
電気光学結晶１６から出射したプローブ光は、再び１／４波長板１５を通過した後、偏光分離部１４に入射する。この例では、水平偏波であるＰ偏光は、そのまま偏光分離部１４を通過し、垂直偏波であるＳ偏光成分が反射して抽出される。すなわち、電気光学結晶１６で偏光変調されたプローブ光は、偏光分離部１４によって強度変調されたＳ偏光とＰ偏光に変換される。 The probe light emitted from the electro-optic crystal 16 passes through the quarter wavelength plate 15 again and then enters the polarization separation unit 14. In this example, P-polarized light that is horizontally polarized light passes through the polarization separation unit 14 as it is, and S-polarized light component that is vertically polarized light is reflected and extracted. That is, the probe light polarization-modulated by the electro-optic crystal 16 is converted into S-polarized light and P-polarized light whose intensity is modulated by the polarization separation unit 14.
抽出されたＳ偏光成分（強度変調光）は、鏡１８で反射した後に第２コリメータ１９を経由して単一モードファイバー２１に入射する。単一モードファイバー２１の他方の端部には図示しない光検出器が接続される。光検出器は、強度変調光を検出することにより、間接的に電波の電界を検出することができる。 The extracted S-polarized component (intensity modulated light) is reflected by the mirror 18 and then enters the single mode fiber 21 via the second collimator 19. A photodetector (not shown) is connected to the other end of the single mode fiber 21. The photodetector can detect the electric field of the radio wave indirectly by detecting the intensity-modulated light.
以上説明したように本実施の形態の電界センサ１は、絶縁基板１０と、絶縁基板１０の上に配置され、偏光状態が保持されて伝搬されたプローブ光を楕円偏光の第１光に変換する１／４波長板１５と、絶縁基板１０の上に配置され、絶縁基板１０に対して傾斜している座面１７ａを持つ台座１７と、座面１７ａの上に配置され、入射して透過する第１光を、受けた電磁波の瞬時電界に対応して偏光変化させた第２光を出射する電気光学結晶１６と、第２光の中から、瞬時電界に対応して偏光変化させた偏光成分を取り出す偏光分離部１４とを備える。 As described above, the electric field sensor 1 according to the present embodiment is arranged on the insulating substrate 10 and the insulating substrate 10 and converts the propagated probe light while maintaining the polarization state into the first elliptically polarized light. A quarter wave plate 15, a pedestal 17 that is disposed on the insulating substrate 10 and has a seating surface 17 a that is inclined with respect to the insulating substrate 10, is disposed on the seating surface 17 a, and is incident and transmitted. The electro-optic crystal 16 that emits the second light whose polarization is changed according to the instantaneous electric field of the received electromagnetic wave, and the polarization component whose polarization is changed according to the instantaneous electric field from the second light. And a polarization separation unit 14 for taking out the light.
本実施の形態の電界センサ１によれば、プローブ光に対する電気光学結晶１６の角度を、簡単に且つ高精度に設定することができる。したがって、高感度な電界センサを容易に製造することを可能にする。 According to the electric field sensor 1 of the present embodiment, the angle of the electro-optic crystal 16 with respect to the probe light can be set easily and with high accuracy. Therefore, it is possible to easily manufacture a highly sensitive electric field sensor.
（電気光学結晶と１／４波長板の角度）
図３に、偏光変調方式による電界センサの基本構成例を示す。偏光変調方式による電界センサは、偏光分離部１４、１／４波長板１５、及び電気光学結晶１６を備える。１／４波長板１５と電気光学結晶１６に示されたｓとｆは、それぞれ偏光素子としてのslow軸（屈折率の大きい軸）とfast軸（屈折率の小さい軸）を表す。電気光学結晶１６に記載された（００１），（１１０）は結晶軸を表す。例えば、閃亜鉛鉱型構造を有する電気光学結晶(GaAs, ZnTe, CdTeなど)の使用が可能である。
(Angle between electro-optic crystal and quarter-wave plate)
FIG. 3 shows a basic configuration example of an electric field sensor using a polarization modulation method. The electric field sensor based on the polarization modulation system includes a polarization separation unit 14, a quarter wavelength plate 15, and an electro-optic crystal 16. S and f shown in the quarter-wave plate 15 and the electro-optic crystal 16 represent a slow axis (a large refractive index axis) and a fast axis (a small refractive index axis) as a polarizing element, respectively. (001) and (110) described in the electro-optic crystal 16 represent crystal axes. For example, an electro-optic crystal (GaAs, ZnTe, CdTe, etc.) having a zinc blende type structure can be used.
図示しないレーザやＬＥＤ等の光源から出射したプローブ光は、偏波保持ファイバーを伝搬した後、電界センサ内の偏光分離部１４に入射する。偏光分離部１４を透過したプローブ光は、１／４波長板１５を通過した後に電気光学結晶１６に入射する。 Probe light emitted from a light source such as a laser or LED (not shown) propagates through the polarization maintaining fiber and then enters the polarization separation unit 14 in the electric field sensor. The probe light transmitted through the polarization separation unit 14 enters the electro-optic crystal 16 after passing through the quarter-wave plate 15.
電界センサの検出感度を向上させるためには、プローブ光の偏光状態に対する１／４波長板１５と電気光学結晶１６の角度を適切に設定する必要がある。 In order to improve the detection sensitivity of the electric field sensor, it is necessary to appropriately set the angles of the quarter-wave plate 15 and the electro-optic crystal 16 with respect to the polarization state of the probe light.
それぞれの適切な角度について検討する。光の偏光状態は、２次元の複素ベクトルによる演算子で表すことができる。 Consider each appropriate angle. The polarization state of light can be expressed by an operator using a two-dimensional complex vector.
図３に示したように、ｘ−ｚ面に偏向した直線偏光である入力光の偏光状態｜ψｉｎ＞は次式で表せる。 As shown in FIG. 3, the polarization state | ψ in > of input light that is linearly polarized light deflected in the xz plane can be expressed by the following equation.
また、図３に示すように配置された偏光分離部１４の反射光に対する作用ＰＴは、次式で表せる。 Further, the action PT on the reflected light of the polarization separation unit 14 arranged as shown in FIG. 3 can be expressed by the following equation.
また、透過光に対する偏光分離部１４の作用ＰＲは次式で表せる。 Moreover, the action P R of the polarization separation section 14 with respect to the transmitted light can be expressed by the following equation.
また、ｘ−ｙ面内での回転を表す行列は次式で表せる。 A matrix representing rotation in the xy plane can be expressed by the following equation.
また、１／４波長板１５の作用Ｑ（θ）は次式で表せる。 The action Q (θ) of the quarter wavelength plate 15 can be expressed by the following equation.
また、電気光学結晶１６の作用Ｃ（φ，Γ）は次式で表せる。ｉは虚数単位である。 The action C (φ, Γ) of the electro-optic crystal 16 can be expressed by the following equation. i is an imaginary unit.
ここでΓは、ポッケルス効果による位相変化であり、電気光学結晶１６内の被測定電界の瞬時値に比例する量である。 Here, Γ is a phase change due to the Pockels effect, and is an amount proportional to the instantaneous value of the electric field to be measured in the electro-optic crystal 16.
出力光の偏光状態は次式で表せる。 The polarization state of the output light can be expressed by the following equation.
光検出器ＰＤで検出されるのは、偏光分離部１４で反射された出力光の強度である。その強度は次式で表せる。 What is detected by the photodetector PD is the intensity of the output light reflected by the polarization separator 14. Its strength can be expressed by the following equation.
電気光学結晶１６の感度は、Γ−Ｉ曲線の微係数に比例する。よって、電気光学結晶１６の感度関数は次式で定義できる。 The sensitivity of the electro-optic crystal 16 is proportional to the derivative of the Γ-I curve. Therefore, the sensitivity function of the electro-optic crystal 16 can be defined by the following equation.
ここで２は、規格化のための定数である。式（１）〜式（８）を用いて電気光学結晶１６の感度関数を求めると、次式を得る。 Here, 2 is a constant for normalization. When the sensitivity function of the electro-optic crystal 16 is obtained using the equations (1) to (8), the following equation is obtained.
図４に、式（１０）の感度関数ｆ（θ，φ）をプロットした結果を示す。図４は、電界センサの感度（0〜1.0）と、光学素子角度の依存性を示す図である。図４（ａ）と（ｂ）の横軸は１／４波長板１５の角度θ、縦軸は電気光学結晶１６の角度φである。 FIG. 4 shows the result of plotting the sensitivity function f (θ, φ) of Equation (10). FIG. 4 is a diagram illustrating the dependence of the sensitivity (0 to 1.0) of the electric field sensor and the optical element angle. 4A and 4B, the horizontal axis represents the angle θ of the quarter-wave plate 15 and the vertical axis represents the angle φ of the electro-optic crystal 16.
図４（ａ）から、例えばθ=22.5°，φ=-22.5°で電界センサの感度が最大になることが分かる。これを一般化すると次のように表せる。 FIG. 4A shows that the sensitivity of the electric field sensor is maximized at θ = 22.5 ° and φ = −22.5 °, for example. This can be generalized as follows.
１／４波長板１５の直交する２つの主軸は、偏光分離部１４の直交する主軸に対して22.5°+ 45°×ｎの角度をなし、且つ、電気光学結晶１６の直交する２つの電気的主軸は、偏光分離部１４の直交する主軸に対して22.5°+ 45°×（２ｍ−１＋ｒ）の角度をなし、ｎとｍは任意の整数とし、r=n mod 2である。n mod 2は、ｎをｐで割った余りを表す。つまり、例えばｎが偶数でr=0、ｎが奇数でr=1とするとθ=22.5°，φ=-22.5°となる。 Two orthogonal main axes of the quarter-wave plate 15 form an angle of 22.5 ° + 45 ° × n with respect to the orthogonal main axis of the polarization separating section 14, and the two orthogonal electric axes of the electro-optic crystal 16 The main axis forms an angle of 22.5 ° + 45 ° × (2m−1 + r) with respect to the orthogonal main axis of the polarization separation unit 14, n and m are arbitrary integers, and r = n mod 2. n mod 2 represents a remainder obtained by dividing n by p. That is, for example, if n is an even number and r = 0, n is an odd number and r = 1, θ = 22.5 ° and φ = −22.5 °.
また、図４（ａ）の一部分を拡大した図４（ｂ）から、光学素子角度が±5°以内であれば、電界センサの感度低下は概ね10％以下に抑えられることが分かる。 Further, from FIG. 4B, which is an enlarged view of a part of FIG. 4A, it can be seen that when the optical element angle is within ± 5 °, the decrease in sensitivity of the electric field sensor can be suppressed to approximately 10% or less.
このように高い感度を得るためには、１／４波長板１５の角度θと電気光学結晶１６の角度φは適切に設定する必要がある。本実施の形態の電界センサ１によれば、電気光学結晶１６の角度φは、台座１７の座面１７ａの傾斜で設定される。したがって、電気光学結晶１６は、簡単に高い精度で配置することが可能である。 In order to obtain such high sensitivity, it is necessary to appropriately set the angle θ of the quarter-wave plate 15 and the angle φ of the electro-optic crystal 16. According to the electric field sensor 1 of the present embodiment, the angle φ of the electro-optic crystal 16 is set by the inclination of the seating surface 17 a of the pedestal 17. Therefore, the electro-optic crystal 16 can be easily arranged with high accuracy.
一方、１／４波長板１５は、その形状の加工が電気光学結晶１６に比べて容易である。例えば、正方形の１／４波長板１５の一辺を22.5°の角度でカットすることは容易である。よって、１／４波長板１５は、一般的な方法でも精度良く配置できる。 On the other hand, the processing of the shape of the quarter-wave plate 15 is easier than that of the electro-optic crystal 16. For example, it is easy to cut one side of the square quarter wave plate 15 at an angle of 22.5 °. Therefore, the quarter-wave plate 15 can be accurately arranged by a general method.
図５に、１／４波長板１５の角度θと電気光学結晶１６の角度φとが適切に設定された場合の電界センサのセンサ感度曲線と、被測定信号波形及び検出信号波形との関係を概念的に示す。図５の横軸は、電気光学結晶１６への印加電界であり、縦軸は、光検出器ＰＤによって検出される出力光強度である。また、ｘ−ｙ平面内の正弦曲線は電界センサの感度曲線を表す。 FIG. 5 shows the relationship between the sensor sensitivity curve of the electric field sensor, the measured signal waveform, and the detected signal waveform when the angle θ of the quarter-wave plate 15 and the angle φ of the electro-optic crystal 16 are appropriately set. Conceptually shown. The horizontal axis in FIG. 5 is the electric field applied to the electro-optic crystal 16, and the vertical axis is the output light intensity detected by the photodetector PD. A sine curve in the xy plane represents a sensitivity curve of the electric field sensor.
電気光学結晶１６と１／４波長板１５の角度を最適化すると、感度曲線の傾きの大きい領域で被測定信号を測定することができる。その結果、振幅が大きく歪みの少ない検出信号波形が得られる。 When the angle between the electro-optic crystal 16 and the quarter-wave plate 15 is optimized, the signal under measurement can be measured in a region where the slope of the sensitivity curve is large. As a result, a detection signal waveform having a large amplitude and a small distortion can be obtained.
図６に、１／４波長板１５の角度θと電気光学結晶１６の角度φとが不適切に設定された場合の電界センサの感度曲線と、被測定信号波形との関係を概念的に示す。横軸と縦軸の関係は、図５と同じである。 FIG. 6 conceptually shows the relationship between the sensitivity curve of the electric field sensor and the measured signal waveform when the angle θ of the quarter-wave plate 15 and the angle φ of the electro-optic crystal 16 are set inappropriately. . The relationship between the horizontal axis and the vertical axis is the same as in FIG.
光学素子角度が不適切であると、電気光学結晶１６の感度曲線の振幅は小さくなり、且つ対称性が失われる。この場合は、検出信号波形の振幅が小さくなると共に波形歪みが現れる。 If the optical element angle is inappropriate, the amplitude of the sensitivity curve of the electro-optic crystal 16 becomes small and the symmetry is lost. In this case, the amplitude of the detection signal waveform decreases and waveform distortion appears.
〔第２の実施の形態〕
図７に、第２の実施の形態に係る電界センサ２の主要部の模式的平面図を示す。電界センサ２は、電界センサ１（図１）に対して主要部が筐体３０に収容されている点で異なる。電界センサ２の主要部の構成は、電界センサ１と同じである。
[Second Embodiment]
FIG. 7 is a schematic plan view of the main part of the electric field sensor 2 according to the second embodiment. The electric field sensor 2 is different from the electric field sensor 1 (FIG. 1) in that a main part is accommodated in a housing 30. The configuration of the main part of the electric field sensor 2 is the same as that of the electric field sensor 1.
筐体３０の形状は、例えば図７に示すようなボトル形状である。ボトル形状の先端の第２部分（首部）３０ｂに、絶縁基板１０の幅の狭い第２領域１０ｂが収容される。また、絶縁基板１０の幅の広い第１領域１０ａは、ボトル形状の第１部分（胴部）３０ａに収容される。また、第１領域１０ａと第２領域１０ｂをつなぐテーパ部１０ｃは、ボトル形状の第３部分（肩部）３０ｃに収容される。第３部分３０ｃは、第１部分３０ａと第２部分１０ｂとを連結する第２部分１０ｂに向けて徐々に幅が狭くなるテーパ状である。 The shape of the housing 30 is, for example, a bottle shape as shown in FIG. The narrow second region 10b of the insulating substrate 10 is accommodated in the second portion (neck portion) 30b at the tip of the bottle shape. The wide first region 10a of the insulating substrate 10 is accommodated in a bottle-shaped first portion (body portion) 30a. Moreover, the taper part 10c which connects the 1st area | region 10a and the 2nd area | region 10b is accommodated in the bottle-shaped 3rd part (shoulder part) 30c. The third portion 30c has a tapered shape that gradually decreases in width toward the second portion 10b that connects the first portion 30a and the second portion 10b.
第１領域１０ａと第２領域１０ｂとテーパ部１０ｃの断面（ｘ−ｙ面）は、例えば円形である。また、それぞれの円の中心は共通である。 The cross section (xy plane) of the first region 10a, the second region 10b, and the tapered portion 10c is, for example, a circle. Moreover, the center of each circle is common.
また、円の中心と電気光学結晶１６の中心を一致させても良い。そうすることで、電界センサ２をｘ−ｙ面内で回転させても、電気光学結晶１６の中心は動かない。よって、センサ感度を安定化させることができる。また、テーパ部１０ｃ（第３部分１０ｃ）を設けることにより、被測定電波が、絶縁基板１０の第領域１０ａ及び筐体３０の第１部分３０ａで反射して被測定物に直接戻ることを防ぐことができる。 Further, the center of the circle and the center of the electro-optic crystal 16 may be matched. By doing so, even if the electric field sensor 2 is rotated in the xy plane, the center of the electro-optic crystal 16 does not move. Therefore, sensor sensitivity can be stabilized. Further, by providing the tapered portion 10c (the third portion 10c), the measured radio wave is prevented from being reflected by the first region 30a of the insulating substrate 10 and the first portion 30a of the housing 30 and returning directly to the measured object. be able to.
筐体３０は、絶縁材料で構成される。その材料は、被測定電波の反射を減らすために、誘電率の低い例えばテフロン（登録商標）、デルリン等が好適である。なお、筐体３０の形状を、断面が円で説明したが、この例に限定されない。断面は、正方形又は長方形の矩形で有っても構わない。 The housing 30 is made of an insulating material. The material is preferably made of, for example, Teflon (registered trademark), Delrin, or the like having a low dielectric constant in order to reduce reflection of the radio wave to be measured. In addition, although the shape of the housing | casing 30 demonstrated the cross section with the circle, it is not limited to this example. The cross section may be a square or a rectangular rectangle.
つまり、本実施の形態の電界センサ２は、絶縁基板１０の幅の広い第１領域１０ａを収容する第１部分と、第１領域１０ａよりも幅の狭い第２領域１０ｂを収容する第２部分とからなる絶縁基板を収容する絶縁性の筐体を備え、第１部分と第２部分の中心、及び電気光学結晶１６の中心が一致している。 That is, the electric field sensor 2 according to the present embodiment includes a first portion that accommodates the first region 10a having a large width of the insulating substrate 10 and a second portion that accommodates the second region 10b that is narrower than the first region 10a. The center of a 1st part and a 2nd part and the center of the electro-optic crystal 16 are in agreement.
以上説明したように本実施の形態の電界センサによれば、センサ感度が最大となる電気光学結晶１６と１／４波長板１５の角度の関係を、容易に且つ適切に設定することができる。したがって、高感度な電界センサの量産を容易にし、電界センサの低コスト化を可能にする。 As described above, according to the electric field sensor of the present embodiment, the angle relationship between the electro-optic crystal 16 and the quarter-wave plate 15 that maximizes the sensor sensitivity can be set easily and appropriately. Therefore, mass production of a highly sensitive electric field sensor is facilitated, and the cost of the electric field sensor can be reduced.
なお、本実施の形態は、台座１７の断面形状を三角形の例で説明したが、この例に限定されない。図８に、変形例の電界センサの先端部から見た模式的構造図を示す。図８に示すように、台座１７は斜面を有する角柱で有っても良い。また、光検出器は、Ｓ偏光成分を検出する例で説明を行ったが、Ｐ偏光成分を検出するようにしても、本実施の形態と同じ作用効果が得られる。 In addition, although this Embodiment demonstrated the cross-sectional shape of the base 17 with the example of the triangle, it is not limited to this example. FIG. 8 shows a schematic structural view as seen from the tip of the electric field sensor of the modification. As shown in FIG. 8, the pedestal 17 may be a prism having a slope. Further, the photodetector has been described with an example in which the S-polarized component is detected. However, even if the P-polarized component is detected, the same effect as that of the present embodiment can be obtained.
このように本発明は、上記の実施の形態に限定されるものではなく、その要旨の範囲内で数々の変形が可能である。 As described above, the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist.
本実施の形態は、電気光学結晶を用いた偏光変調方式による電界センサに適用することができる。図９に、本実施の形態の電界センサ２を用いてホーンアンテナ５０の近傍電界の測定を模式的に示す。電界センサ２は、例えばアンテナ近傍の電界分布を、高い空間分解能で測定することができる。 The present embodiment can be applied to an electric field sensor using a polarization modulation method using an electro-optic crystal. FIG. 9 schematically shows the measurement of the electric field near the horn antenna 50 using the electric field sensor 2 of the present embodiment. The electric field sensor 2 can measure the electric field distribution near the antenna, for example, with high spatial resolution.
１、２：電界センサ
１０：絶縁基板
１０ａ：第１領域
１０ｂ：第２領域
１０ｃ：第３領域
１１：第１コリメータ
１２、１３、１８：鏡
１４：偏光分離部
１５：１／４波長板
１６：電気光学結晶
１６ａ：誘電体鏡
１７：台座
１７ａ：座面
１９：第２コリメータ
２０：偏波保持ファイバー
２１：単一モードファイバー
３０：筐体
３０ａ：第１部分
３０ｂ：第２部分
３０ｃ：第３部分
1, 2: Electric field sensor 10: Insulating substrate 10a: First region 10b: Second region 10c: Third region 11: First collimators 12, 13, 18: Mirror 14: Polarization separation unit 15: 1/4 wavelength plate 16 : Electro-optic crystal 16a: Dielectric mirror 17: Pedestal 17a: Seat surface 19: Second collimator 20: Polarization maintaining fiber 21: Single mode fiber 30: Housing 30a: First part 30b: Second part 30c: Second 3 parts
Claims (7)
前記絶縁基板の上に配置され、偏光の状態が保持されて伝搬されたプローブ光を楕円偏光の第１光に変換する１／４波長板と、
前記絶縁基板の上に配置され、前記絶縁基板に対して傾斜している座面を持つ台座と、
前記座面の上に配置され、入射して透過する前記第１光を、受けた電磁波の瞬時電界に対応して偏光変化させた第２光として出射する電気光学結晶と、
前記第２光の中から、瞬時電界に対応して偏光変化させた偏光成分を取り出す偏光分離部と
を備え、
前記絶縁基板は、平面視において幅の広い第１領域と、前記第１領域よりも幅の狭い第２領域とを備え、
前記第１領域と前記第２領域は、前記第１領域から前記第２領域に向けて徐々に幅が狭くなるテーパ部で連結し、
前記台座と前記電気光学結晶とは、前記第２領域の先端部分に配置され、
前記１／４波長板と前記偏光分離部とは、前記第１領域に配置される
ことを特徴とする電界センサ。 An insulating substrate;
A quarter-wave plate that is disposed on the insulating substrate and converts the probe light propagated while maintaining the polarization state into first elliptically polarized light;
A pedestal disposed on the insulating substrate and having a seating surface inclined with respect to the insulating substrate;
An electro-optic crystal that is disposed on the seating surface and that emits the incident and transmitted first light as second light that has undergone polarization change corresponding to the instantaneous electric field of the received electromagnetic wave;
A polarization separation unit that extracts a polarized component whose polarization has been changed in response to an instantaneous electric field from the second light , and
The insulating substrate includes a first region that is wider in plan view and a second region that is narrower than the first region,
The first region and the second region are connected by a tapered portion whose width gradually decreases from the first region toward the second region,
The pedestal and the electro-optic crystal are disposed at a tip portion of the second region,
Wherein A and the quarter-wave plate the polarization separating part, an electric field sensor, characterized in that that will be disposed in the first region.
且つ、前記電気光学結晶の直交する２つの電気的主軸は、前記偏光分離部の直交する主軸に対して22.5°+ 45°×（２ｍ−１＋ｒ）の角度をなし、
ｎとｍは任意の整数とし、r=n mod 2である
ことを特徴とする請求項１に記載の電界センサ。 Two orthogonal main axes of the quarter-wave plate form an angle of 22.5 ° + 45 ° × n with respect to the orthogonal main axes of the polarization separation unit,
And the two orthogonal electrical principal axes of the electro-optic crystal form an angle of 22.5 ° + 45 ° × (2m−1 + r) with respect to the orthogonal principal axis of the polarization separating section,
The electric field sensor according to claim 1, wherein n and m are arbitrary integers, and r = n mod 2.
前記絶縁基板の上に配置され、前記電気光学結晶が出射する前記第２光を、光検出器に導く第２コリメータと
を備えることを特徴とする請求項１乃至３の何れかに記載の電界センサ。 A first collimator disposed on the insulating substrate and emitting the probe light propagated while maintaining the polarization state as parallel light;
The electric field according to any one of claims 1 to 3 , further comprising: a second collimator disposed on the insulating substrate and guiding the second light emitted from the electro-optic crystal to a photodetector. Sensor.
前記電気光学結晶が出射する前記第２光は、鏡で１回以上反射した後に、前記第２コリメータに入射する
ことを特徴とする請求項４に記載の電界センサ。 The probe light emitted from the first collimator is reflected at least once by a mirror, and then enters the polarization separation unit.
5. The electric field sensor according to claim 4 , wherein the second light emitted from the electro-optic crystal is reflected at least once by a mirror and then enters the second collimator.
前記第１部分と前記第２部分の中心、及び前記電気光学結晶の中心が一致していることを特徴とする請求項１乃至５の何れかに記載の電界センサ。 Insulating housing for accommodating the insulating substrate, comprising: a first portion that accommodates a first region having a wider width of the insulating substrate; and a second portion that accommodates a second region that is narrower than the first region. With
Electric field sensor according to any one of claims 1 to 5, characterized in that the center of the first portion and the second portion, and the center of the electro-optical crystal is consistent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016163427A JP6603634B2 (en) | 2016-08-24 | 2016-08-24 | Electric field sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016163427A JP6603634B2 (en) | 2016-08-24 | 2016-08-24 | Electric field sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2018031642A JP2018031642A (en) | 2018-03-01 |
| JP6603634B2 true JP6603634B2 (en) | 2019-11-06 |
Family
ID=61303387
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2016163427A Active JP6603634B2 (en) | 2016-08-24 | 2016-08-24 | Electric field sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP6603634B2 (en) |
-
2016
- 2016-08-24 JP JP2016163427A patent/JP6603634B2/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| JP2018031642A (en) | 2018-03-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP3521809B1 (en) | Terahertz full-polarization-state detection spectrograph | |
| US9351651B2 (en) | Magnetic field measurement apparatus | |
| CN105353231B (en) | A kind of optical sensing devices suitable for two dimensional electric field measurement | |
| JP3746287B2 (en) | Stress measuring method and apparatus | |
| CN104698410A (en) | Atomic magnetic sensor for magnetometer and method of removing detection dead zones of magnetometer | |
| JP6238058B2 (en) | Terahertz spectroscopy system | |
| WO2012128001A1 (en) | Total reflection spectroscopic measurement method | |
| CN100460854C (en) | Method for measuring semiconductor chip sub-surface damage layer | |
| Fried et al. | A scanning, all-fiber Sagnac interferometer for high resolution magneto-optic measurements at 820 nm | |
| EP2363721B1 (en) | Optical fiber type magnetic field sensor and sensing method | |
| JP6682351B2 (en) | Optical analysis apparatus and optical analysis method | |
| US7769250B2 (en) | Electrooptic probe for measuring temperature and electromagnetic field | |
| JP6603634B2 (en) | Electric field sensor | |
| EP4006558A1 (en) | Interference-type optical magnetic field sensor device | |
| Yallapragada et al. | Direct measurement of the Goos-Hänchen shift using a scanning quadrant detector and a polarization maintaining fiber | |
| US10139655B2 (en) | Method for an optical modulator using the spin hall effect in metals | |
| CN105576495B (en) | Residual amplitude modulation stabilising arrangement based on angle of wedge electro-optic crystal | |
| JP7222480B2 (en) | Interferometric optical magnetic field sensor device | |
| JP2013015437A (en) | Current sensor | |
| US11442119B2 (en) | Magnetometer with optical pumping of a sensitive element with linearly polarised light and multiple-pass in the sensitive element | |
| US8264685B2 (en) | Electrooptic probe for vector measurement of an electromagnetic field | |
| US20190154574A1 (en) | Optical analysis device and optical analysis method | |
| RU2477457C1 (en) | Optoelectronic analyser of optical radiation polarisation | |
| JP2010217116A (en) | Probe and system for measurement of electric signal | |
| Ou et al. | Simultaneous measurement of orthogonal terahertz fields via an emission multiplexing scheme |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20180828 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20190614 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20190625 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20190821 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20191008 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20191011 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 6603634 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |