JPS6347602A - Wave guide type optical displacement sensor - Google Patents
Wave guide type optical displacement sensorInfo
- Publication number
- JPS6347602A JPS6347602A JP18960386A JP18960386A JPS6347602A JP S6347602 A JPS6347602 A JP S6347602A JP 18960386 A JP18960386 A JP 18960386A JP 18960386 A JP18960386 A JP 18960386A JP S6347602 A JPS6347602 A JP S6347602A
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- Japan
- Prior art keywords
- light
- optical waveguide
- optical
- mode
- wave guide
- Prior art date
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- Granted
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 123
- 238000006073 displacement reaction Methods 0.000 title claims abstract description 33
- 239000000758 substrate Substances 0.000 claims abstract description 24
- 230000001902 propagating effect Effects 0.000 claims abstract description 7
- 239000013307 optical fiber Substances 0.000 abstract description 18
- 239000013078 crystal Substances 0.000 abstract description 3
- 239000000835 fiber Substances 0.000 abstract description 3
- 229910003327 LiNbO3 Inorganic materials 0.000 abstract description 2
- 239000000126 substance Substances 0.000 abstract 1
- 230000010287 polarization Effects 0.000 description 7
- 230000000630 rising effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000000644 propagated effect Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
Landscapes
- Instruments For Measurement Of Length By Optical Means (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Optical Radar Systems And Details Thereof (AREA)
Abstract
Description
【発明の詳細な説明】
発明の要約
光学的異方性をもつ基板に2分岐した2本の光導波路を
作製してこれらを参照光用、信号光用とする。TEモー
ド光とT Mモード光とでは屈折率が異なるので光路長
が異なることを利用して。DETAILED DESCRIPTION OF THE INVENTION Summary of the Invention Two optical waveguides branched into two are fabricated on a substrate having optical anisotropy, and these are used for reference light and signal light. This method takes advantage of the fact that TE mode light and TM mode light have different optical path lengths because they have different refractive indices.
TEモードの参照光と信号光との干渉光と、 TMモー
ドの参照光と信号光との干渉光との間に一定の位相差を
もたせることによって、変位全のみならず変位方向をも
判別できるようにした。By creating a certain phase difference between the interference light between the reference light and signal light in TE mode and the interference light between reference light and signal light in TM mode, not only the total displacement but also the direction of displacement can be determined. I did it like that.
発明の背景
技術分野
この発明は、基板上に光導波路を用いてマイケルソン干
渉計を作製し、基板上の反射面で反射するフ照光と基板
外の被測定物体上の反射面で反射する信号光との干渉に
よる光強度変化に基づいて披DI定物体の変位量を計測
する導波型光変位センサに関する。BACKGROUND OF THE INVENTION Technical Field This invention fabricates a Michelson interferometer using an optical waveguide on a substrate, and detects light reflected from a reflective surface on the substrate and a signal reflected from a reflective surface on an object to be measured outside the substrate. The present invention relates to a waveguide type optical displacement sensor that measures the amount of displacement of a fixed object based on changes in light intensity due to interference with light.
先願発明
出願人は既にこの種の導波型光変位センサについていく
つかの提案を行なっている。たとえば。The applicant of the prior invention has already made several proposals regarding this type of waveguide type optical displacement sensor. for example.
特願昭60−142837号、特願昭60−14263
8号、特願昭6O−142H9号などである。とくに、
後2者の特許出願には、被測定物体の変位量のみならず
その変位方向をも判別することのできる導波型光変位セ
ンサが開示されて、いる。被測定物体の変位方向を判別
するためには2つの干渉光が必要であり。Patent Application No. 1983-142837, Patent Application No. 14263-1983
No. 8, Japanese Patent Application No. 6O-142H9, etc. especially,
The latter two patent applications disclose a waveguide type optical displacement sensor that can determine not only the amount of displacement of an object to be measured but also the direction of displacement. Two interference lights are required to determine the direction of displacement of the object to be measured.
しかもこれらの干渉光はその位相が相互に一定角度(た
とえばπ−/4またはπ/2など)ずれていなければな
らない。したがって基板上には2系統の光干渉計の作製
が必要であり、2つの干渉光を取出すために2本の光フ
ァイバが必要となる。入力光を基板に導入するためにも
う1本の光ファイバを要するから、少なくとも合計3本
の光ファイバが必要である。Furthermore, the phases of these interference lights must be shifted from each other by a certain angle (for example, π-/4 or π/2). Therefore, it is necessary to fabricate two systems of optical interferometers on the substrate, and two optical fibers are required to extract the two interference lights. One more optical fiber is required to introduce the input light into the substrate, so at least three optical fibers in total are required.
発明の概要
この発明は、構成のより簡素化を図った導波型光変位セ
ンサを提供するものである。SUMMARY OF THE INVENTION The present invention provides a waveguide type optical displacement sensor with a simpler configuration.
この発明による導波型光変位センサは、光学的異方性を
もつ基板上に、端面に反射面が形成された参照光用光導
波路と、@面から出射して被測定物体に連動する鏡面に
投射される信号光用の光導波路と、入力光をこれらの参
照光用および信号光用光導波路に分岐させる分岐光導波
路と、参照光用および信号光用光導波路から戻ってきた
参照光と信号光とを干渉させる干渉用光導波路とを、こ
れらの光導波路を伝播するTEモード光および7Mモー
ド光に対する屈折率が異なるように作製し、干渉用光導
波路を伝播するTEモード干渉光の強度変化と7Mモー
ド干渉光の強度変化との間に一定の位相差が生じるよう
に参照光用光導波路と信号光用光導波路との長さを異な
らせたことを特徴とする。The waveguide type optical displacement sensor according to the present invention includes an optical waveguide for a reference light having a reflective surface formed on the end surface on a substrate having optical anisotropy, and a mirror surface that is emitted from the @ surface and interlocks with the object to be measured. an optical waveguide for the signal light projected onto the optical waveguide, a branching optical waveguide for branching the input light into the reference light and signal light optical waveguides, and a reference light and the reference light returned from the reference and signal light optical waveguides. Interference optical waveguides that interfere with the signal light are fabricated so that the refractive index for the TE mode light and the 7M mode light propagating through these optical waveguides are different, and the intensity of the TE mode interference light propagating through the interference optical waveguide is It is characterized in that the lengths of the reference light optical waveguide and the signal light optical waveguide are made different so that a certain phase difference occurs between the intensity change and the intensity change of the 7M mode interference light.
Y分岐光導波路を利用して基板上に上記の各種光導波路
を作製する場合には9分岐光導波路と干渉用光導波路と
は共通部分をもっことになろう。When the various optical waveguides described above are fabricated on a substrate using a Y-branch optical waveguide, the nine-branch optical waveguide and the interference optical waveguide will have common parts.
いわゆる非対称X分岐光導波路を用いて上記の各種光導
波路を基板に作製することもできる。The various optical waveguides described above can also be fabricated on a substrate using a so-called asymmetric X-branch optical waveguide.
基板上の分岐光導波路にTEモード光と7Mモード光と
を導入するためには偏波面保存光ファイバを用いればよ
い。また、干渉用光導波路からの出射光は偏光ビーム・
スプリッタによってTEモード光と7Mモード光とに分
離すればよい。A polarization maintaining optical fiber may be used to introduce the TE mode light and the 7M mode light into the branched optical waveguide on the substrate. In addition, the light emitted from the interference optical waveguide is a polarized beam.
It is sufficient to separate the light into TE mode light and 7M mode light using a splitter.
分離されたTEモード光と7Mモード光とをそれぞれ別
個の光電変換素子で受光し、その光強度変化を電気信号
に変換する。これらの電気信号を2値化し、2値化パル
ス数を計数することによって被測定物体の変位量を検出
することができる。The separated TE mode light and 7M mode light are received by separate photoelectric conversion elements, and changes in the light intensity are converted into electrical signals. By binarizing these electrical signals and counting the number of binarized pulses, the amount of displacement of the object to be measured can be detected.
また、TEモード光の光強度変化と7Mモード光の光強
度変化とは一定の位相差をもっているので、これらの2
つの受光信号の変化の順序によって彼n1定物体の変位
方向を判定することが可能となる。Furthermore, since there is a certain phase difference between the light intensity changes of the TE mode light and the light intensity changes of the 7M mode light, these two
The direction of displacement of the constant object can be determined based on the order of changes in the two received light signals.
この発明によると、相互に干渉しないTEモード光と7
Mモード光とを用いているから、基板上に1系統の光干
渉計を設けるだけで、変位量の測定のみならず変位方向
の判別をも行なうことが可能となり、基板上の光導波路
の構成が簡素となる。Y分岐光導波路を用いた場合には
1本の光ファイバで入力光の基板への導入と干渉光の導
出とを行なうことができ、非対称X分岐光導波路を用い
た場合にも合計2本の光ファイバで足りるので、光軸調
整等も容易となる。さらにTEモード干渉光と7Mモー
ド干渉光との間の位相差は、参照光用光導波路と信号光
用光導波路との長さを単に異ならせて設定することによ
って与えることができるので、この点からも構成の簡素
化が図られる。According to this invention, TE mode light that does not interfere with each other and 7
Since M-mode light is used, just by installing one optical interferometer on the board, it is possible to not only measure the amount of displacement but also determine the direction of displacement, and the configuration of the optical waveguide on the board becomes simple. When using a Y-branch optical waveguide, a single optical fiber can introduce the input light into the substrate and extract the interference light, and when using an asymmetrical X-branch optical waveguide, a total of two optical fibers can be used. Since an optical fiber is sufficient, optical axis adjustment etc. are also facilitated. Furthermore, the phase difference between the TE mode interference light and the 7M mode interference light can be provided by simply setting the lengths of the reference light optical waveguide and the signal light optical waveguide to be different. The configuration can also be simplified.
実施例の説明 第1図は導波型光変位センサの主要部を示している。Description of examples FIG. 1 shows the main parts of a waveguide type optical displacement sensor.
基板1としてZカットのLiNbo3結晶が用いられて
おり、この基板1上に光導波路パターンのTi膜(厚さ
300人)を形成したのち、ウェット02雰囲気、
1ooo℃で5時間Tiを基板1に熱拡散させることに
よって光導波路が形成されている。この光導波路は9人
力用および出力用(光干渉用)の光導波路12と、参照
光用光導波路13と。A Z-cut LiNbo3 crystal is used as the substrate 1, and after forming an optical waveguide pattern Ti film (thickness: 300 mm) on this substrate 1, it is exposed to a wet 02 atmosphere.
The optical waveguide is formed by thermally diffusing Ti into the substrate 1 at 100° C. for 5 hours. This optical waveguide includes nine optical waveguides 12 for human power and output (for optical interference), and an optical waveguide 13 for reference light.
信号光用光導波路14と、Y分岐光導波路11とから構
成され、光導波路12がY分岐光導波路11によって参
照光用および信号光用の光導波路13.14に接続され
ている。It is composed of a signal light optical waveguide 14 and a Y-branch optical waveguide 11, and the optical waveguide 12 is connected to reference light and signal light optical waveguides 13 and 14 by the Y-branch optical waveguide 11.
参照光用光導波路13は信号光用光導波路14よりも距
離りだけ短く、参照光用光導波路13の終端には反射部
2が設けられている。この反射部2は。The reference light optical waveguide 13 is shorter in distance than the signal light optical waveguide 14, and a reflection section 2 is provided at the end of the reference light optical waveguide 13. This reflecting section 2.
基板1上の光導波路13の終端位置にドライエツチング
によってスロットを形成し、このスロットの内壁面に金
属を蒸着することによって構成することができる。It can be constructed by forming a slot at the end position of the optical waveguide 13 on the substrate 1 by dry etching and depositing metal on the inner wall surface of the slot.
被測定物体に固定された。またはこれと連動するように
結合されたミラーと基板1上の信号光用光導波路14の
終端(基板1の端面)との間にはロット・レンズ3が設
けられている。このレンズ3は、光導波路14から出射
する光をコリメートしてミラー4に投射し1かつその反
射光を集光して光導波路L4に導入するためのものであ
る。このレンズ3の存在によって光導波路14の終端と
ミラー4との間の距離にかかわらず、常にほぼ一定の光
量の信号光(反射光)が光導波路14に戻りかつY分岐
光導波路11に向って光導波路14を伝播するようにな
る。Fixed to the object to be measured. Alternatively, a rot lens 3 is provided between the mirror coupled to the mirror and the terminal end of the signal light optical waveguide 14 on the substrate 1 (the end surface of the substrate 1). This lens 3 is for collimating the light emitted from the optical waveguide 14, projecting it onto the mirror 4, condensing the reflected light, and introducing it into the optical waveguide L4. Due to the presence of this lens 3, a substantially constant amount of signal light (reflected light) always returns to the optical waveguide 14 and toward the Y-branch optical waveguide 11, regardless of the distance between the end of the optical waveguide 14 and the mirror 4. The light then propagates through the optical waveguide 14.
反射部2で反射してY分岐光導波路11に戻る参照光の
強度と、ミラー4で反射して信号光用光導波路14を伝
播しY分岐光導波路11に戻る信号光の強度とがほぼ等
しくなるように1反射部2の反射率またはミラー4の反
射率を調整しておくことが好ましい。The intensity of the reference light that is reflected by the reflection unit 2 and returns to the Y-branch optical waveguide 11 is approximately equal to the intensity of the signal light that is reflected by the mirror 4, propagates through the signal light optical waveguide 14, and returns to the Y-branch optical waveguide 11. It is preferable to adjust the reflectance of the 1 reflecting section 2 or the reflectance of the mirror 4 so that the angle .
光導波路12の端面にはシングル・モードの偏波面保存
光ファイバ(シングル・ボラリゼーション・ファイバ)
21が接続されている。第2図に拡大して示されている
ように、この偏波面保存光ファイバ21は、中心のコア
22のX軸方向の上下位置に応力発生用のガラス・ファ
イバ24がそのサポート23内に挿入されてなり、TE
モード(X軸方向)および7Mモード(X軸方向)の光
をその偏波面を一方向に保存して伝播させることができ
る。また、光ファイバ21はその上記Xおよびy軸方向
′が基板結晶1のZおよびY軸方向に一致した状態で、
光導波路12に接続されている。A single mode polarization maintaining optical fiber (single polarization fiber) is installed at the end face of the optical waveguide 12.
21 is connected. As shown in an enlarged view in FIG. 2, this polarization-maintaining optical fiber 21 has stress-generating glass fibers 24 inserted into its support 23 at upper and lower positions in the X-axis direction of the central core 22. Became TE
Mode (X-axis direction) and 7M mode (X-axis direction) light can be propagated while maintaining the plane of polarization in one direction. Further, the optical fiber 21 is arranged in such a state that the above-mentioned X and Y axis directions' coincide with the Z and Y axis directions of the substrate crystal 1.
It is connected to the optical waveguide 12.
したがって、光フアイバ21内を伝播してきたTEモー
ド、7Mモードの両モード光が光導波路12内に導入さ
れかつ光導波路11.13.14等を伝播していくこと
になる。Therefore, both the TE mode and 7M mode light propagated in the optical fiber 21 are introduced into the optical waveguide 12 and propagate through the optical waveguides 11, 13, 14, etc.
一方のモードの光、たとえばTEモードの光についてみ
ると、この光は光導波路12からY分岐光導波路11に
進み、ここで強度が等しく分岐されて光導波路13と1
4とに進む。参照光用光導波路13を伝播する光は反射
部2で反射して光導波路13を逆方向に進み、Y分岐光
導波路11に戻る(参照光)。信号光用光導波路14に
進んだ光は、この光導波路14から出射してロッド・レ
ンズ3を経てミラー4に向う。ミラー4で反射した光は
再びロッド・レンズ3を経て光導波路14に入射し、こ
の光導波路14を逆方向に伝播してY分岐光導波路11
に戻る(信号光)。これらの参照光と信号光はY分岐光
導波路11から光導波路12を進むが、ここで相互に干
渉し合い、参照光と信号光との位相差に応じた強度をも
つ干渉光が得られる。この干渉光(出力光)は光導波路
■2から先ファイバ21に進み、後述する測定系に送ら
れる。参照光と信号光の位相差は、これら2つの光の間
の光路差、すなわちミラー4の変位量に依存している。Regarding light in one mode, for example, TE mode light, this light travels from the optical waveguide 12 to the Y-branch optical waveguide 11, where it is split with equal intensity and passes through the optical waveguides 13 and 1.
Proceed to 4. The light propagating through the reference light optical waveguide 13 is reflected by the reflection section 2, travels through the optical waveguide 13 in the opposite direction, and returns to the Y-branch optical waveguide 11 (reference light). The light that has proceeded to the signal light optical waveguide 14 exits from this optical waveguide 14, passes through the rod lens 3, and heads toward the mirror 4. The light reflected by the mirror 4 passes through the rod lens 3 again and enters the optical waveguide 14, propagates through this optical waveguide 14 in the opposite direction and enters the Y-branch optical waveguide 11.
Return to (signal light). These reference light and signal light travel from the Y-branch optical waveguide 11 to the optical waveguide 12, where they interfere with each other, and interference light having an intensity corresponding to the phase difference between the reference light and the signal light is obtained. This interference light (output light) travels from the optical waveguide 2 to the destination fiber 21 and is sent to a measurement system to be described later. The phase difference between the reference light and the signal light depends on the optical path difference between these two lights, that is, the amount of displacement of the mirror 4.
出力光強度の変位量(光路差)に対する変化が第4図に
示されている(たとえばNo、lの波形)。出力光強度
は光路差の変化に対してλ(光の波長)の周期で正弦的
に変化する。信号光は光導波路14の出力端とミラー4
との間を往復するので光路差はミラー4の変位量の2倍
に等しい。FIG. 4 shows changes in the output light intensity with respect to the amount of displacement (optical path difference) (for example, waveforms No. and I). The output light intensity changes sinusoidally with a period of λ (light wavelength) with respect to changes in the optical path difference. The signal light is transmitted between the output end of the optical waveguide 14 and the mirror 4.
The optical path difference is equal to twice the amount of displacement of the mirror 4.
TEモードの光についても同じように、ミラー4の変位
量を表わす強度をもつ干渉光(出力光)が得られる。Similarly, for the TE mode light, interference light (output light) having an intensity representing the amount of displacement of the mirror 4 is obtained.
ところで、ZカットLiNbO3基板1はTEモード光
と7Mモード光に対して異なる屈折率を与えるから、そ
して、参照光用光導波路13と信号光用光導波路14が
それらの長さにおいてしたけ異なるように設定されてい
るから、これらのTEモード光の干渉光とT Mモード
光の干渉光との間には、第4図にNo、1. No、2
で示されているように、ある一定の位相差が生じること
になる。相互に一定の位相シフトが与えられた2つの干
渉光No、1. No、2の変化の順序によってミラー
4の変位方向の判別ができる。By the way, since the Z-cut LiNbO3 substrate 1 gives different refractive indexes to the TE mode light and the 7M mode light, the reference light optical waveguide 13 and the signal light optical waveguide 14 are made to have different lengths. Since the interference light of the TE mode light and the interference light of the TM mode light are set to 1 to 1 in FIG. No, 2
As shown in , a certain phase difference will occur. Two interference lights No. 1 to which a certain phase shift is given to each other. The direction of displacement of the mirror 4 can be determined based on the order of changes in No. and 2.
光導波路13と14との長さの差しは次のようにして設
定できる。The difference in length between the optical waveguides 13 and 14 can be set as follows.
光としてHe−Neレーザ(λ−0,833a m )
を用い、常温の条件下において、光導波路の屈折率は、
TM、TEモード光に対してそれぞれ次式%式%
[
[
光導波路長にLの違いがある場合に、TEモード光と7
Mモード光の光路長がこれに応じて異なる。He-Ne laser (λ-0,833am) as light
At room temperature, the refractive index of the optical waveguide is
For TM and TE mode light, the following formula % formula % [[ If there is a difference of L in the optical waveguide length, TE mode light and 7
The optical path length of the M mode light varies accordingly.
これら2つのモードの光の位相差Δは。The phase difference Δ between these two modes of light is.
Δ−2πL ([No] −[Nel )/λ= 2
πL X 0.1233
(λ−0,833μm)
となる。Δ−2πL ([No] − [Nel)/λ= 2
πL x 0.1233 (λ-0,833 μm).
位相差Δを2π/8とした場合に、第1図の構成では光
は光導波路を往復するので干渉光(No、1とNo、2
)の位相差は2π/4となる。When the phase difference Δ is 2π/8, in the configuration shown in Fig. 1, the light travels back and forth through the optical waveguide, so interference light (No.
) is 2π/4.
この場合におけるLは。L in this case is.
Δ−2π/8 一2πLx 0.1233 より L = 1.014μm となる。Δ−2π/8 -2πLx 0.1233 Than L = 1.014μm becomes.
2つの干渉光の位相差が2π/4であれば被測定物体の
変位方向の判別は可能である。If the phase difference between the two interference lights is 2π/4, it is possible to determine the displacement direction of the object to be measured.
2つの干渉光の位相差が2πのときは、これらの干渉光
強度のグラフは重なってしまうから、変位方向の判別は
できない。位相差が2πのとき。When the phase difference between the two interference lights is 2π, the graphs of the intensities of these interference lights overlap, making it impossible to determine the direction of displacement. When the phase difference is 2π.
L = 8.113μmである。L = 8.113 μm.
したがって、2つの干渉光の位相差が2π/4であるた
めの光導波路長差しは最終的には次式で与えられる。Therefore, the difference in optical waveguide length for the phase difference between the two interference lights to be 2π/4 is finally given by the following equation.
L−1,014+mX 8.113(μm)mは正の
整数
±0.2μm程度の光導波路作製精度で充分に変位方向
の判別が可能となることが分るであろう。It will be understood that L-1,014+mX 8.113 (μm) m is a positive integer with an optical waveguide fabrication accuracy of about ±0.2 μm, which makes it possible to sufficiently determine the displacement direction.
さて、第3図および第4図を参照して全体的な動作につ
いて説明しておく。Now, the overall operation will be explained with reference to FIGS. 3 and 4.
光源としてHe−Neレーザ31が用いられている。こ
のレーザ光はアイソレータ32およびビーム・スプリッ
タ33を経て、レンズ34によって偏波面保存光ファイ
バ2■に入射する。アイソレータ32は反射光がレーザ
31に戻らないようにするためである。直線偏光のレー
ザ光を、その偏波面が光ファイバ21のX軸、y軸に対
して45@傾くようにして、光ファイバ21に導入する
と、光ファイバ21を伝播するTEモード光と7Mモー
ド光の強度が等しくなる。この光ファイバ21を通して
TEモード光および7Mモード光が基板1上の光導波路
に送られる。A He-Ne laser 31 is used as a light source. This laser light passes through an isolator 32 and a beam splitter 33, and enters the polarization maintaining optical fiber 22 through a lens 34. The purpose of the isolator 32 is to prevent reflected light from returning to the laser 31. When a linearly polarized laser beam is introduced into the optical fiber 21 with its plane of polarization inclined by 45@ with respect to the X-axis and y-axis of the optical fiber 21, TE mode light and 7M mode light propagating through the optical fiber 21 are generated. The intensities of will be equal. TE mode light and 7M mode light are sent to the optical waveguide on the substrate 1 through this optical fiber 21.
光ファイバ21を戻ってきたTEモード干渉光およびT
Mモード干渉光は、光ビーム・スプリッタ33で方向が
変換される。こられの互いに直交する偏波面をもつ2つ
の干渉光は、偏光ビーム・スプリッタ35で分けられ、
それぞれ受光素子38A、 38Bで受光される。The TE mode interference light and T
The direction of the M-mode interference light is changed by the optical beam splitter 33. These two interference lights with mutually orthogonal polarization planes are separated by a polarizing beam splitter 35,
The light is received by light receiving elements 38A and 38B, respectively.
これらの干渉光信号は受光素子38A、 36Bでそれ
ぞれ電気信号に変換されたのち、適当なスレシホールド
・レベルをもつ回路37A、 37Bでそれぞれレベル
弁別され、2値化される。この2値化信号の立上りおよ
び/または立下りがカウンタ38A。These interfering optical signals are converted into electric signals by light receiving elements 38A and 36B, respectively, and then level-discriminated and binarized by circuits 37A and 37B having appropriate threshold levels, respectively. The rising edge and/or falling edge of this binary signal is detected by the counter 38A.
3813によって計数される。したがって、ミラー4の
変位量はλ/2またはλ/4単位でal11定される。It is counted by 3813. Therefore, the amount of displacement of the mirror 4 is determined in units of λ/2 or λ/4.
λ/4の場合には、約0.16μmの分解能で変位量が
測定できることになる。第4図に示すN001またはN
o、2 (T Eモードまたは7Mモード)の2値化信
号のいずれか一方のみを用いて変位量が/IPj定でき
るのはいうまでもない。In the case of λ/4, the amount of displacement can be measured with a resolution of about 0.16 μm. N001 or N shown in Figure 4
It goes without saying that the amount of displacement /IPj can be determined using only one of the binary signals of 0 and 2 (TE mode or 7M mode).
他方、上記の2値化信号は微分回路39A、 39Bで
その立上りおよび/または立下りが検出され、この微分
された信号が方向判別回路40に人力する。On the other hand, the rise and/or fall of the above binary signal is detected by differentiating circuits 39A and 39B, and this differentiated signal is input to direction determining circuit 40.
ミラー4が基板1から遠ざかる方向に動くときには、た
とえばスレシホールド回路37Aの出力信号の立上り(
立下り)が同日路37Bの出力信号の立上り(立下り)
よりも先に現われ、ミラー4が逆方向に動くときにはこ
れらの2つの信号の変化の順序が逆になる。2つの微分
回路39A、 39Bの出力の変化が現われる順序に基
づいてミラー4の移動方向が判別回路40により判別さ
れる。方向判別回路40はCPUによって構成すること
も可能である。When the mirror 4 moves in the direction away from the substrate 1, for example, the rising edge of the output signal of the threshold circuit 37A (
The falling edge) is the same day as the rising edge (falling edge) of the output signal of path 37B.
, and when the mirror 4 moves in the opposite direction, the order of change of these two signals is reversed. A determining circuit 40 determines the moving direction of the mirror 4 based on the order in which changes in the outputs of the two differentiating circuits 39A and 39B appear. The direction determination circuit 40 can also be configured by a CPU.
に記実施例では、Y分岐光導波路を中心にして?!成板
上光導波路が形成されているが、上述した先願に示され
ているような非対称X分岐光導波路を用いてもこの発明
は実現できる。In the embodiment described in , the Y-branch optical waveguide is the main focus. ! Although a plated optical waveguide is formed, the present invention can also be realized using an asymmetrical X-branched optical waveguide as shown in the above-mentioned prior application.
図面はこの発明の実施例を示し、第1図は導波型光変位
センサの主要部を示す斜視図、第2図は偏波面保存光フ
ァイバと基板上の光導波路との結合の配置を示す図、第
3図は光変位測定系全体の構成を示す構成およびブロッ
ク図、第4図は干渉光強度信号とそれに基づいてつくら
れた二値化信号を示す波形図である。
1・・・基板。
2・・・反射部。
4・・・被測定物体に連動するミラー。
11・・・Y分岐光導波路。
12・・・入力用および出力用(光干渉用)光導波路。
13・・・参照光用光導波路。
14・・・信号光用光導波路。
以 上
特許出願人 立石電機株式会社
代 理 人 弁理士 牛久 健司
(外1名)The drawings show embodiments of the present invention, with Fig. 1 being a perspective view showing the main parts of a waveguide type optical displacement sensor, and Fig. 2 showing the arrangement of coupling between a polarization-maintaining optical fiber and an optical waveguide on a substrate. 3 is a configuration and block diagram showing the overall configuration of the optical displacement measurement system, and FIG. 4 is a waveform diagram showing an interference light intensity signal and a binary signal created based on the interference light intensity signal. 1... Board. 2... Reflective part. 4...Mirror linked to the object to be measured. 11...Y branch optical waveguide. 12... Optical waveguide for input and output (for optical interference). 13... Optical waveguide for reference light. 14... Optical waveguide for signal light. Patent applicant Tateishi Electric Co., Ltd. Representative Patent attorney Kenji Ushiku (1 other person)
Claims (1)
る信号光用の光導波路と、 入力光をこれらの参照光用および信号光用光導波路に分
岐させる分岐光導波路と、 参照光用および信号光用光導波路から戻ってきた参照光
と信号光とを干渉させる干渉用光導波路とを、 これらの光導波路を伝播するTEモード光およびTMモ
ード光に対する屈折率が異なるように作製し、 干渉用光導波路を伝播するTEモード干渉光の強度変化
とTMモード干渉光の強度変化との間に一定の位相差が
生じるように参照光用光導波路と信号光用光導波路との
長さを異ならせたことを特徴とする、 導波型光変位センサ。[Scope of Claims] An optical waveguide for a reference light having a reflective surface formed on an end face on a substrate having optical anisotropy, and a signal light emitted from the end face and projected onto a mirror surface interlocking with a measured object. A branching optical waveguide that branches the input light into these optical waveguides for reference light and signal light, and a branching optical waveguide that causes the reference light and signal light returned from the optical waveguides for reference light and signal light to interfere with each other. Interference optical waveguides are fabricated to have different refractive indexes for TE mode light and TM mode light propagating through these optical waveguides, and intensity changes of TE mode interference light and TM mode interference light propagating through the interference optical waveguides are A waveguide type optical displacement sensor, characterized in that a reference light optical waveguide and a signal light optical waveguide have different lengths so that a certain phase difference occurs between the intensity change of the reference light and the signal light.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18960386A JPH0684884B2 (en) | 1986-08-14 | 1986-08-14 | Waveguide optical displacement sensor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18960386A JPH0684884B2 (en) | 1986-08-14 | 1986-08-14 | Waveguide optical displacement sensor |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6347602A true JPS6347602A (en) | 1988-02-29 |
JPH0684884B2 JPH0684884B2 (en) | 1994-10-26 |
Family
ID=16244074
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP18960386A Expired - Lifetime JPH0684884B2 (en) | 1986-08-14 | 1986-08-14 | Waveguide optical displacement sensor |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0684884B2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05302976A (en) * | 1992-04-24 | 1993-11-16 | Agency Of Ind Science & Technol | Distance measuring apparatus |
WO2007037241A1 (en) * | 2005-09-28 | 2007-04-05 | Japan Science And Technology Agency | Shear measuring method and its device |
JP2008309645A (en) * | 2007-06-14 | 2008-12-25 | National Institute Of Advanced Industrial & Technology | Inner diameter measuring device |
-
1986
- 1986-08-14 JP JP18960386A patent/JPH0684884B2/en not_active Expired - Lifetime
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05302976A (en) * | 1992-04-24 | 1993-11-16 | Agency Of Ind Science & Technol | Distance measuring apparatus |
WO2007037241A1 (en) * | 2005-09-28 | 2007-04-05 | Japan Science And Technology Agency | Shear measuring method and its device |
JPWO2007037241A1 (en) * | 2005-09-28 | 2009-04-09 | 独立行政法人科学技術振興機構 | Shear measuring method and apparatus |
US7845231B2 (en) | 2005-09-28 | 2010-12-07 | Japan Science And Technology Agency | Shear measuring method and its device |
JP4615568B2 (en) * | 2005-09-28 | 2011-01-19 | 独立行政法人科学技術振興機構 | Shear measuring method and apparatus |
EP1942331A4 (en) * | 2005-09-28 | 2015-09-02 | Japan Science & Tech Agency | Shear measuring method and its device |
JP2008309645A (en) * | 2007-06-14 | 2008-12-25 | National Institute Of Advanced Industrial & Technology | Inner diameter measuring device |
Also Published As
Publication number | Publication date |
---|---|
JPH0684884B2 (en) | 1994-10-26 |
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