JPS6069573A - Magnetic field measuring device and optical frequency modulator - Google Patents
Magnetic field measuring device and optical frequency modulatorInfo
- Publication number
- JPS6069573A JPS6069573A JP17722783A JP17722783A JPS6069573A JP S6069573 A JPS6069573 A JP S6069573A JP 17722783 A JP17722783 A JP 17722783A JP 17722783 A JP17722783 A JP 17722783A JP S6069573 A JPS6069573 A JP S6069573A
- Authority
- JP
- Japan
- Prior art keywords
- plate
- magnetic field
- semiconductor laser
- faraday rotator
- reflecting
- 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.)
- Granted
Links
Landscapes
- Measuring Magnetic Variables (AREA)
- Light Guides In General And Applications Therefor (AREA)
Abstract
Description
【発明の詳細な説明】
la)発明の技術分野
本発明は、ヘテロゲイン方式の磁場測定装置に係り、と
くに光を用いてヘテロダイン方式により磁場を測定する
装置に関する。DETAILED DESCRIPTION OF THE INVENTION la) Technical Field of the Invention The present invention relates to a heterogain magnetic field measuring device, and more particularly to a device that measures a magnetic field by a heterodyne method using light.
(b)技術の背景
近年ボール素子あるいは磁気抵抗効果素子等の小型の固
体トランスデュサーを用いる方法が実用化されている。(b) Background of the Technology In recent years, methods using small solid-state transducers such as ball elements or magnetoresistive elements have been put into practical use.
この他ジョセフソン効果を用いた5IJUID (Su
perconducting Quntum InLe
rferenceDevice )のような高精度磁場
測定が可能な素子も開発されている。In addition, 5IJUID (Su
perconducting Quantum InLe
Elements capable of high-precision magnetic field measurement, such as rferenceDevice), have also been developed.
tc+従来技術と問題点
ホール素子や磁気抵抗効果素子は、その内部における電
流担体の運動の磁場による変化を起電力あるいは電流の
変化として検出するものであって、一般に得られる測定
精度はそれほど高くはない。tc+ Conventional technology and problems Hall elements and magnetoresistive elements detect changes in the movement of current carriers inside them due to magnetic fields as changes in electromotive force or current, and the measurement accuracy that can be obtained is generally not very high. do not have.
一方、5QUIDは1磁束量子程度の微弱磁束を検出可
能であるが、測定素子を極低温に冷却する必要があり、
装置が大がかりとなるために、その適用は特殊な目的の
みに限定される。On the other hand, 5QUID can detect weak magnetic flux of about 1 flux quantum, but the measurement element needs to be cooled to an extremely low temperature.
Due to the large scale of the device, its application is limited to special purposes.
(d1発明の目的
本発明は、比較的小型で高精度の測定を可能とする新規
な磁場測定装置を提供することを目的とする。。(d1 Purpose of the Invention The object of the present invention is to provide a novel magnetic field measurement device that is relatively small and capable of high-precision measurement.
(e1発明の構成
本発明は、半導体レーザの一方の光出射端側にλ/4板
と反射鏡をこの順で、他方の光出射端側にλ/4板とフ
ァラデー回転子と反射鏡とをこの順で、かつそれぞれの
λ/4板の軸が、該半導体レーザの活性層の面に対して
、→−45度または一45度の角度を成すようにして、
各々を配置して測定系を構成し、いずれか一方の反射鏡
から出射される右廻りと左廻りの円偏光の差周波数を計
測することによって、該測定系もしくは少なくとも該フ
ァラデー回転子が置かれてルする磁場の強度をめ、ある
いは半導体レーザの一方の光出射端側にλ/4板と反射
鏡をこの順で、他方の光出射端側にλ/4板とファラデ
ー回転子と反射鏡とをこの順で、かつそれぞれのλ/4
板の軸が、該半導体レーザの活性層の面に対して、+4
5度ままたは一45度の角度を成すようにして各々を配
置するとともに、少なくとも該ファラデー回転子が置か
れている磁場の強度を変化させる手段を配置して変調系
を構成し、いずれか一方の反射鏡から出射される右廻り
と左廻りの円偏光の差周波数を変調することことを特徴
とし、その一形態として、半導体レーザの光出射端とλ
/4板との間を偏波保存ファイバで接続した場合を含む
。(e1 Structure of the Invention The present invention includes a λ/4 plate and a reflecting mirror on one light emitting end side of a semiconductor laser, and a λ/4 plate, a Faraday rotator, and a reflecting mirror on the other light emitting end side in this order. in this order, and the axis of each λ/4 plate forms an angle of →-45 degrees or -45 degrees with respect to the plane of the active layer of the semiconductor laser,
By arranging each of them to configure a measurement system and measuring the difference frequency between the clockwise and counterclockwise circularly polarized light emitted from one of the reflecting mirrors, the measurement system or at least the Faraday rotator is placed. In order to increase the strength of the magnetic field that is transmitted, a λ/4 plate and a reflecting mirror are placed in this order on one light emitting end of the semiconductor laser, and a λ/4 plate, Faraday rotator, and reflecting mirror are placed on the other light emitting end. and in this order, and each λ/4
The axis of the plate is +4 with respect to the plane of the active layer of the semiconductor laser.
The Faraday rotators are arranged at an angle of up to 5 degrees or 145 degrees, and at least means for changing the strength of the magnetic field in which the Faraday rotator is placed is arranged to constitute a modulation system, and either one It is characterized by modulating the difference frequency between right-handed and left-handed circularly polarized light emitted from a reflecting mirror of the semiconductor laser.
/4 plate is connected with a polarization maintaining fiber.
(f1発明の実施例 以下に本発明の実施例を図面を参照して説明する。(Example of f1 invention Embodiments of the present invention will be described below with reference to the drawings.
図は本発明の一実施例を示し、半導体レーザ1には外部
共振器を形成する反射面(反射鏡)2および3が設けら
れている。さらに反射面2の前にはλ/4板4が、また
反射面3の前にはファラデー回転子5およびλ/4板6
が設けられている。The figure shows one embodiment of the present invention, in which a semiconductor laser 1 is provided with reflecting surfaces (reflecting mirrors) 2 and 3 forming an external resonator. Further, in front of the reflecting surface 2 is a λ/4 plate 4, and in front of the reflecting surface 3 is a Faraday rotator 5 and a λ/4 plate 6.
is provided.
同図において7は偏波保存ファイバと称される光ファイ
バの一種である。In the figure, 7 is a type of optical fiber called a polarization maintaining fiber.
一般に半導体レーザlが構成する共振器には、偏光面が
互いに直交差するTE波およびTM波が存在する。しか
しながら、図に示す構成の系においては、例えば半導体
レーザ1から図上で左側に出射されたTE波は、λ/4
板4を通過することによって、例えば右廻りの円偏光き
なり、これが反射面2で反射されて再びλ/4板4を通
過することによって、偏光面がπ/2回転した直線偏光
、すなわちTM波となる。同様に、半導体レーザ1から
図上で右側に出射された1′M波は、λ/4板6を通過
することによって、例えば左廻りの円偏光となり、反射
面3で反射されたのら、再びλ/4板6を通過すること
によってTE波になる。すなわち、TE波として出射さ
れた光は反射面2および3の間を1往復したのちは、や
はりTE波に戻る。逆にTM波として出射された光は、
反射面2および3の間を1往復したのちは、やはりTM
波に戻る。In general, a resonator constituted by a semiconductor laser 1 contains TE waves and TM waves whose polarization planes are orthogonal to each other. However, in the system with the configuration shown in the figure, for example, the TE wave emitted from the semiconductor laser 1 to the left side in the figure is λ/4
By passing through the plate 4, for example, clockwise circularly polarized light is reflected, and by passing through the λ/4 plate 4 again, linearly polarized light whose polarization plane has been rotated by π/2, that is, a TM wave. becomes. Similarly, the 1'M wave emitted from the semiconductor laser 1 to the right in the figure passes through the λ/4 plate 6 and becomes, for example, counterclockwise circularly polarized light, and after being reflected by the reflecting surface 3, It becomes a TE wave by passing through the λ/4 plate 6 again. That is, after the light emitted as a TE wave makes one round trip between the reflecting surfaces 2 and 3, it returns to a TE wave. On the other hand, the light emitted as TM waves is
After one round trip between reflective surfaces 2 and 3, the TM
Back to the waves.
上記の系においては、ファラデー回転子5を通過する2
種類の光、つまり図上で半導体レーザ1の右側に出射さ
れたTE波および耐波は、それぞれ互いに逆廻りの円偏
光となっている。ファラデー回転子5は磁場の下では、
右廻りと左廻りの円偏光のそれぞれに対して、異なった
屈折率を示す。In the above system, 2 passing through the Faraday rotator 5
The different kinds of light, that is, the TE wave and the wave resistance emitted to the right side of the semiconductor laser 1 in the diagram, are each circularly polarized light in opposite directions. Under the magnetic field, the Faraday rotator 5 is
It exhibits different refractive indices for right-handed and left-handed circularly polarized light.
したがっζ、それぞれの円偏光が、一定厚さのファラデ
ー回転子5を通過するに要する時間に差が生じることに
なる。その結果、上記2種類の光に対して反射面2およ
び3間の距離が見掛は上界なり、これらの光は異なった
共振周波数を持つことになる。Therefore, there will be a difference in the time required for each circularly polarized light to pass through the Faraday rotator 5 having a constant thickness. As a result, the distance between the reflecting surfaces 2 and 3 appears to be an upper bound for the two types of light, and these lights have different resonance frequencies.
ここで、ファラデー回転子が設けられていないか、また
は設けられていても磁場が加えられ°ζいない場合は、
右廻りと左廻りの円偏光は互いに時間反転をした関係に
あるので縮退している。ファラデー回転子に磁場が加え
られると縮退が解かれて、それぞれのモードの光は、周
波数がω」−Δωおよびω−Δωで与えられる2つの光
となる。ただし、ωは中心の周波数である。Here, if a Faraday rotator is not provided, or if a magnetic field is not applied even if it is provided, then
The clockwise and counterclockwise circularly polarized light are in a time-reversal relationship with each other, so they are degenerate. When a magnetic field is applied to the Faraday rotator, the degeneracy is broken and each mode of light becomes two lights whose frequencies are given by ω'-Δω and ω-Δω. However, ω is the center frequency.
したがって、加えられる磁場を制御して変化させる手段
を設りることにより、光周波数変1!、l器を構成する
ことができる。Therefore, by providing a means for controlling and changing the applied magnetic field, the optical frequency can be changed by 1! , l device can be constructed.
一方、ファラデー回転子が右廻および左廻りの各円偏光
に対して示す屈折率の差が磁場強度に比例する。すなわ
ち、
HrNll 1 oo l(
ただし、nrおよびnlはそれぞれ右廻りおよび左廻り
の円偏光に対する屈折率、Hは磁場強度である。したが
って、上記差周波数Δωは磁場強度Hに比例して変化す
ることになり、該Δωを検出することによって、磁場強
度を知ることができるので、磁場測定装置も構成するこ
とができる。On the other hand, the difference in refractive index that the Faraday rotator exhibits for each of the right-handed and left-handed circularly polarized lights is proportional to the magnetic field strength. That is, HrNll 1 oo l (where nr and nl are the refractive indices for clockwise and counterclockwise circularly polarized light, respectively, and H is the magnetic field strength. Therefore, the above difference frequency Δω changes in proportion to the magnetic field strength H. By detecting this Δω, the magnetic field strength can be determined, so a magnetic field measuring device can also be constructed.
該Δωの検出は、前記のようにし°(発生させた周波数
ω+Δωおよびω−Δωの2つの光を干渉させて11〕
られるビー1へ信号を検出することによって行うことが
できる。この方法によれば、直線偏光をファラデー回転
子を通過させノコ際に生じる偏光面の回転角の変化を検
出する、従来から公知の磁場測定方法に比し−C1数桁
以上の高精度の測定が可能となる。The detection of Δω is performed as described above (by interfering two lights of the generated frequencies ω+Δω and ω−Δω 11).
This can be done by detecting a signal to the bee 1 that is transmitted. According to this method, the measurement accuracy is several orders of magnitude higher than that of conventional magnetic field measurement methods, which pass linearly polarized light through a Faraday rotator and detect changes in the rotation angle of the plane of polarization that occur when sawing. becomes possible.
図示した測定系においては、偏波保存ファイハフが設げ
られている。該偏波保存ファイバは、その中を通過する
光の偏光モードを保存することができる性質を有する光
ファイバとし゛C市販されているものである。光源とし
て半導体レーザを用いた場合には、前記のように偏光面
が互いに直交するTE波および耐波が出射されfiるが
、偏波保存ファイバ内部においては、該TE波およびT
M波は空間を伝播する場合におけると同じように互いに
独立に通過する。したがって、該偏波保存ファイバを用
いることによって、図に示す系の左半分(半導体レーザ
1、λ/4板4、反射面2)の光軸と、右半分(λ/4
板6、ファラデー回転子5、反射面3)の光軸とが一致
するような空間配置を取る必要がな(なる。すなわち、
上記系の右半分のみを測定ずべき磁場中に設置して、測
定が可能となるのである。その結果、上記系の右半分を
小さなブロー゛プとして構成し、これを用いて高精度の
磁場測定を行うことを可能とする。該測定装置において
は、プローブとレーザ光源を含む装置本体間は光ファイ
バにより結合されているために、外部誘導ノイズによる
精度の低下を生じない利点がflられるのはもちろんで
ある。In the illustrated measurement system, a polarization preserving fiber is provided. The polarization maintaining fiber is a commercially available optical fiber having the property of preserving the polarization mode of light passing through it. When a semiconductor laser is used as a light source, TE waves and T waves whose polarization planes are perpendicular to each other are emitted as described above, but inside a polarization maintaining fiber, the TE waves and T waves are
The M waves pass independently of each other, just as they do when propagating through space. Therefore, by using the polarization maintaining fiber, the optical axis of the left half (semiconductor laser 1, λ/4 plate 4, reflection surface 2) of the system shown in the figure and the right half (λ/4
There is no need to take a spatial arrangement such that the optical axes of the plate 6, Faraday rotator 5, and reflection surface 3 coincide with each other.
Measurements can be made by placing only the right half of the system in the magnetic field to be measured. As a result, it is possible to configure the right half of the system as a small blow and use it to perform highly accurate magnetic field measurements. In this measuring device, since the probe and the main body of the device including the laser light source are coupled by an optical fiber, there is an advantage that accuracy does not deteriorate due to externally induced noise.
なお、本発明に用いる半導体レーザにおいては、光出射
端面に反射防止用コーティングを施すことが望ましい。Note that in the semiconductor laser used in the present invention, it is desirable to apply an antireflection coating to the light emitting end face.
(g1発明の効果
本発明によれば、冷却を必要としないで、また外部誘導
ノイズの影響を受けずに、微小空間の磁場を高精度で測
定可能とし、また光周波数の変調を可能とする効果があ
る。(g1 Effect of the Invention According to the present invention, it is possible to measure the magnetic field in a minute space with high precision without requiring cooling or being affected by externally induced noise, and it is also possible to modulate the optical frequency. effective.
図は本発明に係る磁場測定装置の構成例を示す図である
。
図において、■は半導体レーザ、2および3は反射面、
4および6はλ/4扱、5はファラデー回転子、7は偏
波保存ファイバである。
f−グ 7
9,1・許庁長宮殿
1・If Iiのノ之小
昭和58’111’J4ゆ1第177227シJ3 浦
」1を1゛る古
°jシ1′1との関1系 ’IFii’l出願人f1ミ
lす1 神4ン用県川崎市中1+it1.(,1:lN
11中1015a地(522)名称富士通株式会社
4 代 理 人 ILI++j 神り用県川崎l1il
l’l+il< 1−lhl1国+101!Vf地富士
通株式会社内
昭和59111II 31 If (発送日)6、?l
Itl1gf−J: Q jj’l/Jlli’ 6ブ
、3uBノEt なし1細書の第5頁第5行目および第
14行目の」」を−[第1鴫と補正する。
、−1」書第8頁第20行目の「図」を「第1図」と補
正する
」書第1O頁第2行目の1図」を「第1図」と補正する
。
(4)図面を別紙の通り補正する0
第 1 図
2The figure is a diagram showing an example of the configuration of a magnetic field measuring device according to the present invention. In the figure, ■ is a semiconductor laser, 2 and 3 are reflective surfaces,
4 and 6 are treated as λ/4, 5 is a Faraday rotator, and 7 is a polarization maintaining fiber. f-gu 7 9, 1・Kochochocho Palace 1・If Ii's Noko Showa 58'111'J4 Yu1 No. 177227shiJ3 Ura"1"1" System 'IFii'l Applicant f1 Mils 1 God 4 Nyo Prefecture Kawasaki City Naka 1 + it 1. (,1:lN
11, 1015a (522) Name: Fujitsu Limited 4 Agent: ILI++j Kawasaki, Kamiori Prefecture, l1il
l'l+il< 1-lhl1 country+101! Vf Fujitsu Ltd. Showa 59111II 31 If (Shipping date) 6,? l
Itl1gf-J: Q jj'l/Jlli' 6b, 3uBnoEt None 1 Correct "" in the 5th line and 14th line of page 5 of the specification to -[1st line. , -1" book, page 8, line 20, ``Figure" is corrected to ``Figure 1.'' Book ``book, page 1 O, line 2, ``Figure 1'' is corrected to ``Figure 1.'' (4) Correct the drawing as shown in the attached sheet0 Figure 1 Figure 2
Claims (4)
射鏡をこの順で、他方の光出射端側にλ/4板とファラ
デー回転子と反射鏡とをこの順で、かつそれぞれのλ/
4板の軸が、該半導体レーザの活性層の面に対して、+
45度または一45度の角度を−成すようにして、各々
を配置して測定系を構成し、いずれか一方の反射鏡から
出射される右廻りと左廻りの円偏光の差周波数を計測す
ることによって、該測定系もしくは少なくとも該ファラ
デー回転子が置かれている磁場の強度をめることを特徴
とする磁場測定装置。(1) A λ/4 plate and a reflecting mirror are placed in this order on one light emitting end side of the semiconductor laser, and a λ/4 plate, Faraday rotator, and reflecting mirror are placed in this order on the other light emitting end side, and Each λ/
The axes of the four plates are + with respect to the plane of the active layer of the semiconductor laser.
A measurement system is constructed by arranging each of them so that they form an angle of 45 degrees or -45 degrees, and the difference frequency between the clockwise and counterclockwise circularly polarized light emitted from either one of the reflecting mirrors is measured. A magnetic field measuring device characterized in that the intensity of the magnetic field in which the measuring system or at least the Faraday rotator is placed is measured by:
保存ファイバで接続したことを特徴とする特許請求の範
囲第1項記載の磁場測定装置。(2) The magnetic field measuring device according to claim 1, characterized in that the light emitting end of the semiconductor laser and the λ/4 plate are connected by a polarization maintaining fiber.
反射鏡をこの順で、他方の光出射端側にλ/4板とファ
ラデー回転子と反射鏡とをこの順で、かつそれぞれのλ
/4板の軸が、該半導体レーザの活性層の面に対して、
+45度または一45度の角度を成すようにして各々を
配置するとともに、少なくとi該ファラデー回転子が置
かれてし・る磁場の強度を変化させる手段を配置して変
調系を構成し、いずれか一方の反射鏡から出射される右
廻りと左廻りの円偏光の差周波数を変調することを特徴
とする光周波数変調器。(3) A λ/4 plate and a reflecting mirror are placed in this order on one light emitting end of the semiconductor laser, and a λ/4 plate, a Faraday rotator, and a reflecting mirror are placed in this order on the other light emitting end. and each λ
The axis of the /4 plate is relative to the surface of the active layer of the semiconductor laser,
arranging them so as to form an angle of +45 degrees or -45 degrees, and configuring a modulation system by arranging means for changing the strength of the magnetic field in which at least i the Faraday rotator is placed, An optical frequency modulator that modulates the difference frequency between right-handed and left-handed circularly polarized light emitted from one of the reflecting mirrors.
保存ファイバで接続したことを特徴とする特許請求の範
囲第3項記載の光周波数変調器。(4) The optical frequency modulator according to claim 3, wherein the light emitting end of the semiconductor laser and the λ/4 plate are connected by a polarization maintaining fiber.
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP17722783A JPH0249667B2 (en) | 1983-09-26 | 1983-09-26 | JIKIKOGAKUSOCHI |
CA000463409A CA1251846A (en) | 1983-09-26 | 1984-09-17 | Laser light source device |
EP84306546A EP0138452B1 (en) | 1983-09-26 | 1984-09-26 | Laser light source device |
KR8405900A KR890003390B1 (en) | 1983-09-26 | 1984-09-26 | Laser light source device |
US06/654,628 US4637027A (en) | 1983-09-26 | 1984-09-26 | Laser light source device |
DE8484306546T DE3483766D1 (en) | 1983-09-26 | 1984-09-26 | LASER LIGHT SOURCE. |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP17722783A JPH0249667B2 (en) | 1983-09-26 | 1983-09-26 | JIKIKOGAKUSOCHI |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6069573A true JPS6069573A (en) | 1985-04-20 |
JPH0249667B2 JPH0249667B2 (en) | 1990-10-30 |
Family
ID=16027373
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP17722783A Expired - Lifetime JPH0249667B2 (en) | 1983-09-26 | 1983-09-26 | JIKIKOGAKUSOCHI |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0249667B2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4955006A (en) * | 1988-01-13 | 1990-09-04 | Fujitsu Limited | Floating type magneto-optic disk reading head system having external semiconductor laser resonator operating at orthogonal two mode oscillations |
JPH0720217A (en) * | 1992-04-28 | 1995-01-24 | Tadashi Sueda | Polarization surface storage optical fiber type magnetic field sensor |
JP2019138775A (en) * | 2018-02-09 | 2019-08-22 | シチズンファインデバイス株式会社 | Magnetic field sensor element and magnetic field sensor device |
-
1983
- 1983-09-26 JP JP17722783A patent/JPH0249667B2/en not_active Expired - Lifetime
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4955006A (en) * | 1988-01-13 | 1990-09-04 | Fujitsu Limited | Floating type magneto-optic disk reading head system having external semiconductor laser resonator operating at orthogonal two mode oscillations |
JPH0720217A (en) * | 1992-04-28 | 1995-01-24 | Tadashi Sueda | Polarization surface storage optical fiber type magnetic field sensor |
JP2019138775A (en) * | 2018-02-09 | 2019-08-22 | シチズンファインデバイス株式会社 | Magnetic field sensor element and magnetic field sensor device |
Also Published As
Publication number | Publication date |
---|---|
JPH0249667B2 (en) | 1990-10-30 |
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