JPS6346364B2 - - Google Patents
Info
- Publication number
- JPS6346364B2 JPS6346364B2 JP59149449A JP14944984A JPS6346364B2 JP S6346364 B2 JPS6346364 B2 JP S6346364B2 JP 59149449 A JP59149449 A JP 59149449A JP 14944984 A JP14944984 A JP 14944984A JP S6346364 B2 JPS6346364 B2 JP S6346364B2
- Authority
- JP
- Japan
- Prior art keywords
- optical
- light
- optical fiber
- coil
- gyroscope
- 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.)
- Expired
Links
- 239000013307 optical fiber Substances 0.000 claims description 45
- 230000003287 optical effect Effects 0.000 claims description 40
- 230000010287 polarization Effects 0.000 claims description 7
- 239000000835 fiber Substances 0.000 description 10
- 230000001902 propagating effect Effects 0.000 description 5
- 238000005452 bending Methods 0.000 description 4
- 238000005253 cladding Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910004298 SiO 2 Inorganic materials 0.000 description 3
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 229910005793 GeO 2 Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 229910052681 coesite Inorganic materials 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 238000005491 wire drawing Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
- G01C19/58—Turn-sensitive devices without moving masses
- G01C19/64—Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams
- G01C19/72—Gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Optics & Photonics (AREA)
- Electromagnetism (AREA)
- Power Engineering (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Gyroscopes (AREA)
- Light Guides In General And Applications Therefor (AREA)
- Lasers (AREA)
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は光ジヤイロスコープ、更に詳しく言え
ば、光フアイバを伝播する光の位相がフアイバの
移動、回転等によつて変ることを利用して、方
位、位置を測定する装置に係る。[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is an optical gyroscope, and more specifically, an optical gyroscope that utilizes the fact that the phase of light propagating through an optical fiber changes due to movement, rotation, etc. of the fiber. , azimuth, and position measurement equipment.
光ジヤイロスコープは円形に巻かれた光フアイ
バコイルの両端から直線偏光を加え、上記コイル
を伝播した２つの光の干渉光の強度を計測するこ
とによつて、上記光フアイバのコイルの回転角や
角速度を検出するものである。その例はR.F.
Cahil et.al.“Solid―state phase―nulling opical
gyro（Appl.Opt.Vol.19、No.18、Sept.1980、p3054
〜3056）に示されている。
An optical gyroscope applies linearly polarized light from both ends of a circularly wound optical fiber coil, and measures the intensity of interference light between the two lights propagating through the coil, thereby determining the rotation angle of the optical fiber coil. It is used to detect angular velocity and angular velocity. An example is RF
Cahil et.al. “Solid―state phase―nulling optical
gyro (Appl.Opt.Vol.19, No.18, Sept.1980, p3054
~3056).
したがつて、光フアイバのコイルを互いに逆方
向に伝播する２方向の光の偏波面は同一平面上に
なければならない。 Therefore, the polarization planes of the two directions of light propagating in opposite directions through the optical fiber coil must be on the same plane.
従来上述のごとき光ジヤイロスコープを実現す
るため、光フアイバとしては献面が円形の単一モ
ードフアイバを使用していた。しかしながら、単
一モードフアイバに直線偏光の光を入射すると、
その出力端における光はその偏光特性がくずれ楕
円偏光になつたり、円偏光になつたり、また、た
とえ直線偏光であつても偏光面の傾きは一定しな
い。この原因は、光フアイバの小さな曲げ、振動
などによつて容易に直交伝搬セード間でエネルギ
ー交換を行うためである。このため２つの出力光
の偏波特性は一定でなく時間的に変動する。この
変動は光フアイバジヤイロスコープの計測ノイズ
として現われ、測定可能な最小の回転角や角速度
を決定する。 Conventionally, in order to realize the above-mentioned optical gyroscope, a single mode fiber with a circular surface has been used as the optical fiber. However, when linearly polarized light is introduced into a single mode fiber,
The polarization characteristics of the light at the output end are distorted and it becomes elliptically polarized light or circularly polarized light, and even if it is linearly polarized light, the inclination of the plane of polarization is not constant. The reason for this is that energy is easily exchanged between the orthogonal propagation shades due to small bends, vibrations, etc. of the optical fiber. Therefore, the polarization characteristics of the two output lights are not constant and vary over time. This variation appears as measurement noise in the fiber optic gyroscope and determines the minimum measurable rotation angle and angular velocity.
また従来の光フアイバは光学的主軸が光フアイ
バの曲げ等で変動するため入射端より入れた光と
他の入射端より入れた光とが同一の光路を取つて
伝搬しているとは保証出来ない。この事は、右廻
りの光と左廻りの光が同一光路長という条件を満
たさず、角速度ωの絶対値を求めるのが難しくな
る。そのため、現在、実用できる光ジヤイロスコ
ープは実現されていない。 In addition, because the optical principal axis of conventional optical fibers fluctuates due to bending of the optical fiber, it is impossible to guarantee that the light entering from the input end and the light entering from other input ends are propagating along the same optical path. do not have. This does not satisfy the condition that the clockwise light and the counterclockwise light have the same optical path length, making it difficult to determine the absolute value of the angular velocity ω. Therefore, a practical optical gyroscope has not yet been realized.
したがつて、本発明の目的は実用できる光ジヤ
イロスコープを実現することである。すなわち、
光コイルの出力の偏波特性が時間的に一定し、か
つ、２つの光の通路が一致するようにした光ジヤ
イロスコープを実現することである。
Therefore, an object of the present invention is to realize a practical optical gyroscope. That is,
An object of the present invention is to realize an optical gyroscope in which the polarization characteristics of the output of an optical coil are temporally constant and two optical paths coincide.
本発明は上記目的を達成するため、光フアイバ
で構成されたコイルの両端から直線偏波を入射
し、その各出力光の干渉光からコイルの回転速度
や回転角を検出する光ジヤイロスコープにおい
て、上記光フアイバを光フアイバの直交する光学
的主軸のそれぞれ沿つた光の位相伝播速度差が大
きな光フアイバで構成し、かつ、光フアイバコイ
ルの両端に加えられる直線偏光波の振動方向が共
に上記光フアイバの同一の光学主軸方向に一致し
て入射するように構成したことを特徴とする。
In order to achieve the above object, the present invention provides an optical gyroscope that inputs linearly polarized waves from both ends of a coil made of optical fiber and detects the rotation speed and rotation angle of the coil from the interference light of each output light. , the optical fiber is constructed of an optical fiber having a large phase propagation velocity difference of light along each of the orthogonal optical principal axes of the optical fiber, and the vibration directions of the linearly polarized waves applied to both ends of the optical fiber coil are both as described above. It is characterized in that it is configured to be incident on the same optical principal axis direction of the optical fiber.
本発明の光ジヤイロスコープによれば、光フア
イバのコイルを右廻りおよび左廻りする直線偏光
が同一の光学主軸を伝播するため、伝播する光の
光路長が常に一定となり、安定じこ動作をする。 According to the optical gyroscope of the present invention, the linearly polarized light that rotates clockwise and counterclockwise around the optical fiber coil propagates along the same principal optical axis, so the optical path length of the propagating light is always constant and stable gyroscope operation is achieved. do.
又、光フアイバの直交する２つの光学的主軸に
おける位相速度が異なるときは、伝播途中におい
て偏波面は、光フアイバの曲げや振動などによつ
て伝播モード間でエネルギー変換など行なわず、
安定した光ジヤイロスコープの動作を行なう。 In addition, when the phase velocities in the two orthogonal optical principal axes of the optical fiber are different, the polarization plane does not undergo energy conversion between the propagation modes during propagation due to bending or vibration of the optical fiber, etc.
Perform stable optical gyroscope operation.
以下、図面を用いて本発明を詳細に説明する。 Hereinafter, the present invention will be explained in detail using the drawings.
第１は光ジヤイロスコープの原理的構成を示す
図である。 The first is a diagram showing the basic configuration of an optical gyroscope.
直線偏光の光Ａがレーザ（光源）１より発し、
半透明鏡によつて２つのビームA1，A2にわかれ、
それぞれ集光レンズ４，５により光フアイバ６の
両端７，８より入射される。光フアイバ６はコイ
ルを形成している。レンズ５で端面８に入射した
光A1は光フアイバ中を時計と反対方向に進み、
光フアイバの他端７より出射し半透明鏡で反射さ
れた光A1′，はスクリーン９に達する。一方レン
ズ４で光フアイバ端７に入射した光A2は時計方
向に光フアイバ内を送搬しフアイバ端８より出射
し鏡３で反射された光A2′はスクリーン９に達す
る。この時光フアイバのドラムが角速度ωで回転
していると光A1とA2にωに比例した位相差を生
じる。このためスクリーン７上には干渉縞があら
われる。この干渉縞はωによつて生じた位相差に
よつて強度が変化するため、逆に強度変化を検出
する事で角速度ωが測定できる。 Linearly polarized light A is emitted from laser (light source) 1,
Split into two beams A 1 and A 2 by a semi-transparent mirror,
The light enters from both ends 7 and 8 of the optical fiber 6 through condensing lenses 4 and 5, respectively. Optical fiber 6 forms a coil. Light A1 incident on the end face 8 of the lens 5 travels in the optical fiber in a counterclockwise direction,
Light A 1 ', which is emitted from the other end 7 of the optical fiber and reflected by the semi-transparent mirror, reaches the screen 9. On the other hand, the light A 2 that enters the optical fiber end 7 through the lens 4 is transmitted clockwise within the optical fiber, exits from the fiber end 8, and is reflected by the mirror 3, where the light A 2 ' reaches the screen 9. At this time, when the optical fiber drum is rotating at an angular velocity ω, a phase difference proportional to ω is generated between the lights A 1 and A 2 . Therefore, interference fringes appear on the screen 7. Since the intensity of these interference fringes changes depending on the phase difference caused by ω, the angular velocity ω can be measured by detecting the change in intensity.
ここで、サブナツク効果を考慮した計算から、
位相差ΔZは、Ｚ＝2ωLR／λC（ω：角速度、Ｌ：フ
アイバの長さ、Ｒ：フアイバの曲げ半径、λ：光
の波長、Ｃ：光速）となる。スクリーン９上の中
心点で強度変化を検出した場合、光強度Ｉは、Ｉ
∝COS2ΔZの関係がある。したがつて光強度Ｉか
らωを逆に求めることができる。 Here, from calculations taking into account the subnack effect,
The phase difference ΔZ is Z=2ωLR/λC (ω: angular velocity, L: length of fiber, R: bending radius of fiber, λ: wavelength of light, C: speed of light). When an intensity change is detected at the center point on the screen 9, the light intensity I is
There is a relationship of ∝COS 2 ΔZ. Therefore, ω can be determined inversely from the light intensity I.
又、この角速度ωをある基準時定から積分すれ
ば、その期間にコイルの回転した角度が測定でき
る。 Furthermore, by integrating this angular velocity ω from a certain reference time, the angle at which the coil rotated during that period can be measured.
なお、第１図は説明の都合上、光源１やハーフ
ミラー２、反射鏡３、レンズ４，５等をコイルの
外部に示しているが、実際にはコイルをまいたド
ラム内に装置してコイルと一体となつて回転でき
るように構成される。又スクリーン９は受光器で
構成され光の干渉輝度を電気信号として取り出す
ように構成される。 For convenience of explanation, Figure 1 shows the light source 1, half mirror 2, reflector 3, lenses 4, 5, etc. outside the coil, but in reality they are installed inside the drum around which the coil is wound. It is constructed so that it can rotate together with the coil. Further, the screen 9 is constituted by a light receiver and is configured to extract interference luminance of light as an electric signal.
本発明の特徴は上記光フアイバ６と、直線偏光
Ａと上記光フアイバ６の２つの入力端７，８の結
合部にある。 The feature of the present invention lies in the optical fiber 6 and the coupling portion between the linearly polarized light A and the two input ends 7 and 8 of the optical fiber 6.
光フアイバ６は外部擾乱があつても直線偏光の
劣化が小さな光フアイバ（偏波面保存フアイバと
呼ぶ）で構成される。例えば第２図ａ，ｂに示す
ような非円形断面のクラツド１１又はジヤケツト
１２″を持つ光フアイバで構成されており、この
長軸ｙは、短軸ｘに対応する光学主軸面に沿つて
伝播する光の位相速度差βx〜βy＝Δβが有意（少
なくとも2π／Δβがコイルの半径より小さい）もので
ある。 The optical fiber 6 is composed of an optical fiber (referred to as a polarization-maintaining fiber) whose linearly polarized light undergoes little deterioration even in the presence of external disturbances. For example, it is composed of an optical fiber having a cladding 11 or a jacket 12'' with a non-circular cross section as shown in FIGS. The phase velocity difference β x to β y =Δβ of the light is significant (at least 2π/Δβ is smaller than the radius of the coil).
これらの光フアイバは本願発明者等によつて先
に開発されたものであり、ジヤケツトとなる石英
管の内壁にクラツド又は第２のジヤケツトとなる
B2O3を含むSiO2層を形成し、さらに、コア又は
光フアイバとなる材質層を化学的気相沈積
（CVD）法によつて形成し外気より若干減圧しな
がら中実のロツトを作り、これを加熱線引するこ
とによつて容易に実現できる。 These optical fibers were developed earlier by the inventors of the present application, and are made by attaching a cladding or a second jacket to the inner wall of a quartz tube that serves as a jacket.
Two layers of SiO containing B 2 O 3 are formed, and a layer of material that will become the core or optical fiber is formed by chemical vapor deposition (CVD), and a solid rod is created while the pressure is slightly lower than that of the outside air. , this can be easily realized by heating wire drawing.
なお、第２図において、１２，１２′，１２″は
ジヤケツト、１１，１１′はクラツド、１０，１
０′はコアを形成し、層１０，１２，１１′，１
２′はSiO2、層１１はB2O3を含むSiO2層１２′は
B2O3とGeO2を含むSiO2、層１０′はGeO2を含む
SiO2からなる。 In Fig. 2, 12, 12', 12'' are jackets, 11, 11' are claddings, and 10, 12'' are jackets.
0' forms the core, layers 10, 12, 11', 1
2' is SiO 2 , layer 11 is SiO 2 layer 12' is B 2 O 3
SiO 2 containing B 2 O 3 and GeO 2 , layer 10′ containing GeO 2
Consists of SiO2 .
本発明の第２の特徴は光源（レーザ）１からの
直線偏波面が上述の光フアイバで構成されたコイ
ルの両入力端面の同一光学的主軸に加えられるこ
とである。第３図はその光入力部の様子を示すも
ので、第１図と同一の番号を付す部分は同一の機
伝、構成を持つ部分である。 A second feature of the present invention is that the linearly polarized wave plane from the light source (laser) 1 is applied to the same optical principal axis of both input end faces of the coil constituted by the above-mentioned optical fiber. FIG. 3 shows the state of the optical input section, and parts given the same numbers as in FIG. 1 are parts having the same mechanism and configuration.
レーザ１からの光はｙ方向の直線偏光波であ
る。この光は半分はハーフミラー２、レンズ４を
介して光コイルの一方の端部７に加えられるが、
この場合、光フアイバの光学主軸ｙ（又はｘ、図
面ではｙ軸の場合を示しているがｘでも良い）と
上記レーザからの直線偏波面と一致するように結
合させる。実際にはハーフミラーとフアイバ入力
端７の間に１／２波長板を挿入し調整する。又レー
ザ１からの直線偏波光の他の半分はハーフミラー
２で反射され、反射ミラー３、レンズ５を介して
光フアイバコイルの他の入力端８に結合される
が、この場合入力端７での結合が光学主軸ｙと一
致させるようにした場合は入力端８の結合も光学
主軸ｙとなるように同一の光学主軸に結合するよ
うに構成されている。 The light from the laser 1 is a linearly polarized wave in the y direction. Half of this light is applied to one end 7 of the optical coil via a half mirror 2 and a lens 4.
In this case, the optical fiber is coupled so that its principal optical axis y (or x; in the drawing, the y-axis is shown, but x may also be used) and the linearly polarized wave plane from the laser. Actually, a 1/2 wavelength plate is inserted between the half mirror and the fiber input end 7 for adjustment. The other half of the linearly polarized light from the laser 1 is reflected by the half mirror 2 and coupled to the other input end 8 of the optical fiber coil via the reflection mirror 3 and lens 5; When the coupling of the input end 8 is made to coincide with the optical principal axis y, the coupling of the input end 8 is also coupled to the same optical principal axis so as to become the optical principal axis y.
このよむにすると両フアイバ入力端より入射し
た光A1，A2は光フアイバの同じ光主軸を通る事
になり、回転が生じていない時の全光路長は等し
くなる。 In this case, the lights A 1 and A 2 entering from both fiber input ends will pass through the same optical principal axis of the optical fiber, and the total optical path length will be equal when no rotation occurs.
上記光学主軸は第２図のような断面構造の光フ
アイバにおいては、ジヤケツトやクラツドにおい
て形成される楕円形状の長軸、短軸と一致する。 In an optical fiber having a cross-sectional structure as shown in FIG. 2, the optical principal axis coincides with the long axis and short axis of the ellipse formed in the jacket and cladding.
そして、各主軸ｘ，ｙ方向における光フアイバ
のコア部の屈折率をnx，ny、光の波長をλとすれ
ば、λ／nx−ny＝2π／Δβ＝Ｌの関係があり、このＬ
が
小さい程外部擾乱のえいきようが少ないので、光
フアイバとしては、nx−ny（歪複屈折）の大きな
ものが良いが、コイルの半径（曲げ）との関係よ
り少なくとも｜nx−ny｜＞λ／R0であることが望ま
しい。ここでR0はコイルの半径を示す。この理
由は、｜nx−ny｜λ／R0の場合、直交する基本モ
ード間でエネルギー変換が生ずるからである。 Then, if the refractive index of the core part of the optical fiber in each principal axis x and y direction is n x , n y , and the wavelength of light is λ, then there is a relationship of λ / n x - ny = 2π / Δβ = L. , this L
The smaller the value, the less the effect of external disturbance, so it is better to use an optical fiber with a large n x −n y (strain birefringence), but from the relationship with the radius (bending) of the coil, at least |n x − It is desirable that n y |>λ/R 0 . Here R 0 indicates the radius of the coil. The reason for this is that when |n x −n y |λ/R 0 , energy conversion occurs between orthogonal fundamental modes.
本発明により実用的にみて安全なジヤイロスコ
ープが提供できるので実用効果は極めて大きい。
Since the present invention can provide a gyroscope that is safe from a practical standpoint, the practical effects are extremely large.
第１図は本発明が適用される光ジヤイロスコー
プの一般的構成を示す図、第２図は本発明による
光ジヤイロスコープに使用される光フアイバの一
実施例の断面図、第３図は本発明による光ジヤイ
ロスコープの光源と光フアイバコイルの形合の動
作説明のための図である。
１…レーザ、２…ハーフミラー、３…反射鏡、
４，５…レンズ、６…光フアイバ、７，８…端
面、９…スクリーン（受光器）。
FIG. 1 is a diagram showing the general configuration of an optical gyroscope to which the present invention is applied, FIG. 2 is a cross-sectional view of an embodiment of an optical fiber used in the optical gyroscope according to the present invention, and FIG. FIG. 2 is a diagram for explaining the operation of the shape of the light source and optical fiber coil of the optical gyroscope according to the present invention. 1...Laser, 2...Half mirror, 3...Reflector,
4, 5... Lens, 6... Optical fiber, 7, 8... End face, 9... Screen (light receiver).
Claims (1)
線偏波を入射し、上記両端からの出力光の干渉輝
度を検出するように構成された光ジヤイロスコー
プにおいて、上記光フアイバが光フアイバの直交
する光学的主軸に沿つた光の位相速度差が異なる
光フアイバで構成され、かつ、上記コイルの両端
に加えられる直線偏光の偏光面が共に上記光フア
イバの同一光学主軸方向に一致して入射するよう
に構成されたことを特徴とする光ジヤイロスコー
プ。1. In an optical gyroscope configured to input linearly polarized waves from both ends of a coil composed of optical fibers and detect interference brightness of output light from both ends, the optical gyroscope is configured such that the optical fibers are orthogonal to each other. It is composed of optical fibers having different phase speed differences of light along the optical principal axis, and the polarization planes of the linearly polarized light applied to both ends of the coil are incident on the same optical principal axis direction of the optical fiber. An optical gyroscope characterized by comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14944984A JPS6040908A (en) | 1984-07-20 | 1984-07-20 | Optical gyroscope |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14944984A JPS6040908A (en) | 1984-07-20 | 1984-07-20 | Optical gyroscope |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2295337A Division JPH0617797B2 (en) | 1990-11-02 | 1990-11-02 | Optical gyroscope |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6040908A JPS6040908A (en) | 1985-03-04 |
| JPS6346364B2 true JPS6346364B2 (en) | 1988-09-14 |
Family
ID=15475360
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14944984A Granted JPS6040908A (en) | 1984-07-20 | 1984-07-20 | Optical gyroscope |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6040908A (en) |
-
1984
- 1984-07-20 JP JP14944984A patent/JPS6040908A/en active Granted
Non-Patent Citations (4)
| Title |
|---|
| APPL.PHYS.LETT=1978 * |
| ELECTRONICS LETTERS=1979 * |
| IEEE JOURNAL OF QUANTUM ELECTRONICS=1981 * |
| OPTICS LETTERS=1979 * |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6040908A (en) | 1985-03-04 |
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