JPH063373Y2 - Bragg cell - Google Patents
Bragg cellInfo
- Publication number
- JPH063373Y2 JPH063373Y2 JP1986002905U JP290586U JPH063373Y2 JP H063373 Y2 JPH063373 Y2 JP H063373Y2 JP 1986002905 U JP1986002905 U JP 1986002905U JP 290586 U JP290586 U JP 290586U JP H063373 Y2 JPH063373 Y2 JP H063373Y2
- Authority
- JP
- Japan
- Prior art keywords
- acoustic wave
- surface acoustic
- wave
- waveguide
- bragg cell
- 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 - Lifetime
Links
Description
【考案の詳細な説明】 〔産業上の利用分野〕 この考案は、弾性表面波と光表面波との相互作用を用い
て周波数の分析を行うブラッグセルに関するものであ
る。[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a Bragg cell for performing frequency analysis using the interaction between surface acoustic waves and surface acoustic waves.
第２図は、例えば文献Proceedings of the IEEE,vol.6
4,No.3,March 1976,pp.318-328やApplied Optics,vol.1
9,No.18,15September 1980,pp.3033-3034などに示され
ている従来のこの種のブラッグセルを示す図である。Figure 2 shows, for example, the document Proceedings of the IEEE, vol.6.
4, No. 3, March 1976, pp.318-328 and Applied Optics, vol.1
FIG. 9 is a view showing a conventional Bragg cell of this type shown in 9, No. 18, 15 September September 1980, pp. 3033-3034 and the like.
図中、１はＬｉＮｂＯ３などの圧電体基板、２は圧電体
基板１の表面に、Ｔｉなどの金属を拡散して形成した光
表面波導波路、３表面波発生手段としてのレーザダイオ
ード、４はレンズ、５は偏向角度検出手段としての受光
素子アレイ、６は弾性表面波発生手段としての弾性表面
波励振用すだれ状電極である。In the figure, 1 is a piezoelectric substrate such as LiNbO 3 , 2 is an optical surface wave waveguide formed by diffusing a metal such as T i on the surface of the piezoelectric substrate 1, laser diodes as surface wave generating means, 4 Is a lens, 5 is a light receiving element array as a deflection angle detecting means, and 6 is a surface-wave-exciting interdigital electrode as a surface acoustic wave generating means.
次に動作について説明する。レーザダイオード３から光
表面波導波路２に入射した光表面波は、レンズ４により
平行光に変換され、もう一方のレンズ４により受光素子
アレイ５が取付けられた端面に集束する。このとき、す
だれ状電極６により励振された弾性表面波ビームと、光
表面波ビームとを、ある特定の角度でクロスさせれば、
光表面波のビームは、弾性表面波を励振しない場合にお
ける方向からある特定のずれた角度方向へ偏向する。し
たがってレンズ４により集束されたビームスポット位置
がずれ、弾性表面波が励振されていない場合とは異なっ
た受光素子の出力が最大となる。さらに、上記偏向角度
は、弾性表面波の周波数に依存するため、受光素子アレ
イ５中のどの受光素子の出力が最大になっているかを検
出すれば、弾性表面波の周波数を知ることができる。Next, the operation will be described. The surface acoustic wave that has entered the surface acoustic wave waveguide 2 from the laser diode 3 is converted into parallel light by the lens 4, and is focused by the other lens 4 on the end face to which the light receiving element array 5 is attached. At this time, if the surface acoustic wave beam excited by the interdigital transducer 6 and the surface acoustic wave beam are crossed at a specific angle,
The surface acoustic wave beam is deflected in a certain angular direction deviating from the direction in the case where the surface acoustic wave is not excited. Therefore, the position of the beam spot focused by the lens 4 is displaced, and the output of the light receiving element becomes maximum, which is different from the case where the surface acoustic wave is not excited. Further, since the deflection angle depends on the frequency of the surface acoustic wave, the frequency of the surface acoustic wave can be known by detecting which light receiving element in the light receiving element array 5 has the maximum output.
したがってレーダ受信電波をＲＦ帯に周波数変換し、こ
の信号を用いてすだれ状電極６を介して弾性表面波を励
振しておけば、レーダ受信電波の周波数分析を行うこと
ができる。Therefore, if the radar reception radio wave is frequency-converted to the RF band and the surface acoustic wave is excited via the interdigital transducer 6 using this signal, the frequency analysis of the radar reception radio wave can be performed.
ところで、広帯域にわたって周波数分析を行いたい場合
には、すだれ状電極６は広帯域な周波数特性を有する必
要がある。すだれ状電極６の帯域幅は圧電体基板１の材
料定数により左右され、結合係数が大きい方が帯域幅は
広くなる。ＬｉＮｂＯ３などは結合係数が大きい材料で
ある。By the way, in order to perform frequency analysis in a wide band, the interdigital transducer 6 needs to have wide band frequency characteristics. The band width of the interdigital transducer 6 depends on the material constant of the piezoelectric substrate 1, and the band width increases as the coupling coefficient increases. LiNbO 3 and the like are materials having a large coupling coefficient.
しかし、第２図に示したように、従来この種のブラッグ
セルでは、ＬｉＮｂＯ３などの圧電体基板１の表面全体
にわたってＴｉなどの金属を拡散していた。このため、
すだれ状電極６が配置してある部分の基板の結晶構造は
ＬｉＮｂＯ３などの結晶そのものとは異なったものとな
り、材料定数も異なるものとなる。したがって、特に弾
性表面波の波長が短い高周波数帯では、すだれ状電極６
の弾性表面波励振効率が劣化し、広帯域特性が得られな
くなる欠点があった。However, as shown in FIG. 2, in the Bragg cell of this type, a metal such as T i has been diffused over the entire surface of the piezoelectric substrate 1 such as LiNbO 3 conventionally. For this reason,
The crystal structure of the substrate in the portion where the interdigital transducer 6 is arranged is different from the crystal itself of LiNbO 3 or the like, and the material constant is also different. Therefore, especially in the high frequency band where the wavelength of the surface acoustic wave is short, the interdigital transducer 6
However, there is a drawback that the surface acoustic wave excitation efficiency is deteriorated and wide band characteristics cannot be obtained.
この考案は上記のような欠点を解消するためになされた
もので、広帯域にわたり効率よく弾性表面波を励振で
き、広帯域にわたる周波数を分析できるブラッグセルを
得ることを目的とする。The present invention has been made in order to solve the above drawbacks, and an object thereof is to obtain a Bragg cell capable of efficiently exciting surface acoustic waves over a wide band and analyzing frequencies over a wide band.
この考案に係るブラッグセルは、光表面波導波路を圧電
体表面の一部に金属を拡散することにより形成し、弾性
表面波発生手段を上記光導波路以外の圧電体基板の表面
に形成するようにしたものである。In the Bragg cell according to the present invention, the surface acoustic wave waveguide is formed by diffusing metal on a part of the surface of the piezoelectric body, and the surface acoustic wave generating means is formed on the surface of the piezoelectric body substrate other than the optical waveguide. It is a thing.
この考案においては、弾性表面波発生手段が配置される
部分の基板の結晶構造を、結晶そのものと同一に保つこ
とにより、効率よく広帯域にわたって弾性表面波を励振
でき、広帯域にわたる信号の周波数分析が可能となる。In this invention, by keeping the crystal structure of the substrate in the portion where the surface acoustic wave generating means is arranged the same as that of the crystal itself, the surface acoustic wave can be efficiently excited over a wide band, and frequency analysis of signals over a wide band is possible. Becomes
以下、この考案の一実施例を図について説明する。第１
図において、１は圧電体基板、３は表面波発生手段とし
てのレーザダイオード、４はレンズ、５は偏向角度検出
手段としての受光素子アレイ、６は弾性表面波発生手段
としてのすだれ状電極であり、これらは従来と同様のも
のである。しかし、第１図に示すように、Ｔｉなどを拡
散して形成する光表面波導波路２は、圧電体基板１の表
面において特定の領域、すなわち、光表面波が伝播する
領域のみに制限してある。An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1 is a piezoelectric substrate, 3 is a laser diode as a surface wave generating means, 4 is a lens, 5 is a light receiving element array as a deflection angle detecting means, and 6 is an interdigital electrode as a surface acoustic wave generating means. , These are the same as conventional ones. However, as shown in FIG. 1, the optical surface wave waveguide 2 formed by diffusion and T i is the specific area in the surface of the piezoelectric substrate 1, that is, limited to the region where the light surface wave propagates There is.
第１図に示すブラッグセルにおいても、従来と同様に、
レーザダイオード３から光表面波導波路２に入射した光
表面波はレンズ４により平行光に変換され、他のレンズ
４により、受光素子アレイ５が取付けられた端面に集束
する。また、すだれ状電極６により励振された弾性表面
波ビームと光表面波ビームとを、従来と同様の角度でク
ロスさせれば、光表面波ビームの方向は、従来と同様の
方向に偏向し、この方向は弾性表面波の周波数に依存す
るから、受光素子アレイ５中のどの受光素子の出力強度
が大きいかを検出、識別することにより、周波数分析を
行うことができる。Also in the Bragg cell shown in FIG. 1, as in the conventional case,
The surface acoustic wave that has entered the surface acoustic wave waveguide 2 from the laser diode 3 is converted into parallel light by the lens 4, and is focused by the other lens 4 on the end face to which the light receiving element array 5 is attached. Further, if the surface acoustic wave beam and the surface acoustic wave beam excited by the interdigital transducer 6 are crossed at the same angle as in the conventional case, the direction of the surface acoustic wave beam is deflected in the same direction as in the conventional case, Since this direction depends on the frequency of the surface acoustic wave, the frequency analysis can be performed by detecting and identifying which of the light receiving elements in the light receiving element array 5 has the higher output intensity.
しかし、この考案に係るブラッグセルでは、従来と異な
り、第１図に示すようにＴｉなどを拡散する領域を制限
し、すだれ状電極６の配置された領域は拡散を行ってお
らず、圧電体基板１の結晶構造と同じ結晶構造に保って
ある。However, in the Bragg cell according to the present invention, unlike the prior art, as shown in FIG. 1, the region where T i or the like is diffused is limited, and the region where the interdigital transducer 6 is arranged does not diffuse, so that the piezoelectric body is not formed. The crystal structure is the same as that of the substrate 1.
したがって、圧電体基板１として、従来と同様に結合係
数が大きいＬｉＮｂＯ３結晶などを用いれば、すだれ状
電極６の弾性表面波励振効率は高周波数においても従来
に比べ良好に保てる。すなわち、この考案に係るブラッ
グセルでは、広帯域にわたり弾性表面波を効率よく励振
できるから、従来に比べ広帯域にわたる信号の周波数分
析を行える利点がある。Therefore, if the piezoelectric substrate 1 is made of LiNbO 3 crystal or the like having a large coupling coefficient as in the conventional case, the surface acoustic wave excitation efficiency of the interdigital transducer 6 can be maintained better than in the conventional case even at high frequencies. That is, in the Bragg cell according to the present invention, surface acoustic waves can be efficiently excited over a wide band, so that there is an advantage that frequency analysis of a signal over a wide band can be performed as compared with the conventional case.
さらに、弾性表面波が光と相互作用を生じる領域と、す
だれ状電極６との間の弾性表面波伝播路において、Ｔｉ
の拡散部はその一部を占めるのみであるから、高い周波
数におけるＴｉの拡散部による伝搬損失は従来に比べ少
ない。このことによってもブラッグセルの特性を広い帯
域において良好に保つことができる。Further, in the surface acoustic wave propagation path between the region where the surface acoustic wave interacts with light and the interdigital transducer 6, the Ti
The diffusion loss of Ti occupies only a part thereof, so that the propagation loss due to the diffusion portion of Ti at a high frequency is smaller than that of the conventional case. This also makes it possible to maintain good Bragg cell characteristics in a wide band.
なお、以上は第１図に示す一実施例の場合について説明
したが、この考案はこれに限らず、Ｔｉなどを拡散して
形成する光表面波導波路２の領域は、光表面波が伝播す
る領域をカバーし、すだれ状電極６が配置される領域を
避けた別の形状にしてもよい。Although the case of the embodiment shown in FIG. 1 has been described above, the invention is not limited to this, and the surface acoustic wave propagates in the region of the surface acoustic wave waveguide 2 formed by diffusing Ti or the like. The shape may be different so as to cover the area and avoid the area where the interdigital transducer 6 is arranged.
以上のように、この考案に係るブラッグセルは、光表面
波導波路を圧電体表面の一部に金属を拡散することによ
り形成し、弾性表面波発生手段っを上記光導波路以外の
圧電体基板の表面に形成するようにしたので、弾性表面
波励振効率を広帯域にわたって良好に保ち、かつ弾性表
面波の伝搬損失を小さくすることができ、このため広帯
域にわたる信号の周波数分析を行える利点がある。As described above, in the Bragg cell according to the present invention, the surface acoustic wave waveguide is formed by diffusing metal on a part of the surface of the piezoelectric body, and the surface acoustic wave generating means is provided on the surface of the piezoelectric substrate other than the optical waveguide. Since the surface acoustic wave excitation efficiency is kept good over a wide band and the propagation loss of the surface acoustic wave can be reduced, it is possible to analyze the frequency of the signal over a wide band.
第１図はこの考案の一実施例によるブラッグセルを示す
図、第２図は従来のブラッグセルを示す図である。１は
圧電体基板、２は光表面波導波路、３はレーザダイオー
ド、４はレンズ、５は受光素子アレイ、６はすだれ状電
極である。 なお、図中同一符号は同一、又は相当部分を示す。FIG. 1 is a diagram showing a Bragg cell according to an embodiment of the present invention, and FIG. 2 is a diagram showing a conventional Bragg cell. Reference numeral 1 is a piezoelectric substrate, 2 is a surface acoustic wave waveguide, 3 is a laser diode, 4 is a lens, 5 is a light receiving element array, and 6 is a comb-shaped electrode. The same reference numerals in the drawings indicate the same or corresponding parts.
Claims (1)
光表面波を入射して一定方向に伝播させる表面波発生手
段と、上記圧電体基板の表面側に形成された光表面波導
波路と、上記光表面波に偏向を与えるための弾性表面波
を励振する弾性表面波発生手段と、上記光表面波の偏向
角度を検出する受光手段とを備えたブラッグセルにおい
て、 上記光表面波導波路を圧電体表面の一部に金属を拡散す
ることにより形成し、上記弾性表面波発生手段を上記光
表面波導波路以外の圧電体の表面に形成することを特徴
とするブラッグセル。1. A piezoelectric substrate, a surface wave generating means for injecting an optical surface wave on the surface side of the piezoelectric substrate and propagating the surface wave in a fixed direction, and an optical surface wave guide formed on the surface side of the piezoelectric substrate. A Bragg cell including a waveguide, a surface acoustic wave generating means for exciting a surface acoustic wave for giving a deflection to the surface acoustic wave, and a light receiving means for detecting a deflection angle of the surface acoustic wave, wherein the surface acoustic wave waveguide Is formed by diffusing a metal on a part of the surface of the piezoelectric body, and the surface acoustic wave generating means is formed on the surface of the piezoelectric body other than the optical surface wave waveguide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1986002905U JPH063373Y2 (en) | 1986-01-13 | 1986-01-13 | Bragg cell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1986002905U JPH063373Y2 (en) | 1986-01-13 | 1986-01-13 | Bragg cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62116224U JPS62116224U (en) | 1987-07-23 |
| JPH063373Y2 true JPH063373Y2 (en) | 1994-01-26 |
Family
ID=30782178
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1986002905U Expired - Lifetime JPH063373Y2 (en) | 1986-01-13 | 1986-01-13 | Bragg cell |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH063373Y2 (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60156038A (en) * | 1984-01-23 | 1985-08-16 | Canon Inc | Optical function element and its manufacture |
-
1986
- 1986-01-13 JP JP1986002905U patent/JPH063373Y2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62116224U (en) | 1987-07-23 |
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