JP2737007B2 - Signal detector - Google Patents
Signal detectorInfo
- Publication number
- JP2737007B2 JP2737007B2 JP1180286A JP18028689A JP2737007B2 JP 2737007 B2 JP2737007 B2 JP 2737007B2 JP 1180286 A JP1180286 A JP 1180286A JP 18028689 A JP18028689 A JP 18028689A JP 2737007 B2 JP2737007 B2 JP 2737007B2
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- Japan
- Prior art keywords
- signal
- current
- detector
- superconductor
- signal detector
- Prior art date
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- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、超伝導体の電流−電圧特性に基づき発生す
る電圧を検出することで光信号を検出する信号検出器に
関する。Description: TECHNICAL FIELD The present invention relates to a signal detector for detecting an optical signal by detecting a voltage generated based on current-voltage characteristics of a superconductor.
［従来の技術］ 従来の超伝導体を用いた信号検出器、特に光信号を検
出する検出器としては、超伝導体を利用したものが知ら
れている［Japanese Journal of Applied Physics vol.
23 L333（1984）］。この光信号検出器は、第４図に示
すように、酸化物超伝導体BaBb0.7Bi0.3O3（BPBO）薄膜
でマイクロブリッジ型ジョセフソン接合を形成し、この
接合部に光を照射し、ジョセフソン接合の臨界電流値の
変化を利用するものである。かかる検出器においては、
受光部の材料としてBPBOを用いており、これは臨界温度
が約13Kと低い。すなわち、検出器を動作させるには、
液体ヘリウム等を使用しなければならない。また、かか
る検出器の特性は、ジョセフソン接合の特性によって決
定される。[Prior Art] As a conventional signal detector using a superconductor, particularly a detector using a superconductor is known [Japanese Journal of Applied Physics vol.
23 L333 (1984)]. In this optical signal detector, as shown in FIG. 4, a microbridge-type Josephson junction is formed from an oxide superconductor BaBb 0.7 Bi 0.3 O 3 (BPBO) thin film, and this junction is irradiated with light. It utilizes the change in the critical current value of a Josephson junction. In such a detector,
BPBO is used as the material of the light receiving section, and its critical temperature is as low as about 13K. That is, to operate the detector,
Liquid helium or the like must be used. The characteristics of such a detector are determined by the characteristics of the Josephson junction.
［発明が解決しようとする課題］ 上記従来例においては、例えばイメージセンサーのよ
うに同時に多数の検出器を作用するとき、加工のバラツ
キ等に起因する検出器間の特性のバラツキを補正しにく
いという問題がある。[Problems to be Solved by the Invention] In the above conventional example, when a large number of detectors are operated at the same time like an image sensor, for example, it is difficult to correct variations in characteristics between the detectors due to processing variations and the like. There's a problem.
また、超伝導体の分光特性により、検出する光の波長
域も限定されるため、広範囲の波長帯域の信号検出に適
していないという問題もある。Further, since the wavelength range of light to be detected is also limited by the spectral characteristics of the superconductor, there is a problem that it is not suitable for signal detection in a wide wavelength band.
さらには、接合部への光照射において、その領域が非
常に限定されるため、位置合せの精度を要するという問
題もある。Further, there is a problem that the accuracy of alignment is required because the area of the light irradiation to the joint is very limited.
すなわち、本発明の目的とするところは、超伝導物質
の電流−電圧特性を利用することにより、上述のような
問題点を解決することにある。That is, an object of the present invention is to solve the above-mentioned problems by utilizing the current-voltage characteristics of a superconducting material.
［課題を解決するための手段］ 本発明の特徴とするところは、光信号の入力により電
流が生じる信号入力部と、該発生電流を注入することに
よって光信号を検出する超伝導体を用いた信号検出部と
を少なくとも有する信号検出器であって、前記信号検出
部は、該信号入力部とは電気的に接続されているが離間
して配置されており、該発生電流の注入により該超伝導
体に該超伝導体の臨界電流値を越える電流を流して該超
伝導体の両端に発生する電圧を検出することで光信号を
検出するものである信号検出器にある。[Means for Solving the Problems] A feature of the present invention is to use a signal input section in which a current is generated by input of an optical signal and a superconductor which detects the optical signal by injecting the generated current. A signal detector having at least a signal detection unit, wherein the signal detection unit is electrically connected to the signal input unit but is arranged at a distance therefrom. A signal detector detects an optical signal by flowing a current exceeding a critical current value of the superconductor to a conductor and detecting a voltage generated at both ends of the superconductor.
また、前記信号検出部にマイクロブリッジ型ジョセフ
ソン接合を用いた信号検出器、あるいは、前記信号入力
部に光伝導性材料を用いた信号検出器を特徴とするもの
である。Further, the present invention is characterized in that a signal detector using a micro-bridge type Josephson junction for the signal detection unit or a signal detector using a photoconductive material for the signal input unit.
ここで、本発明を達成するために用いられる信号検出
部としての超伝導体としては、単結晶又は多結晶から成
る超伝導特性を有する材料であれば何でも良い。尚、検
出器をより高い温度で動作させるためには、臨界温度の
高い材料が好ましい。この点でＹ−Ba−Cu−Ｏ系、Bi−
Sr−Ca−Cu−Ｏ系、Tl−Sr−Ca−Cu−Ｏ系セラミックス
材料のような液体窒素の沸点である77Kより高い臨界温
度を持つ物質が適している。Here, as a superconductor as a signal detection unit used for achieving the present invention, any material having superconducting characteristics made of a single crystal or a polycrystal may be used. In order to operate the detector at a higher temperature, a material having a higher critical temperature is preferable. In this respect, Y-Ba-Cu-O system, Bi-
Materials having a critical temperature higher than the boiling point of liquid nitrogen, 77 K, such as Sr-Ca-Cu-O-based and Tl-Sr-Ca-Cu-O-based ceramic materials are suitable.
一方、検出器の動作温度は、使用する超伝導体の臨界
温度より低い温度であれば良いが、入力信号の検出感度
を上げるためにも臨界温度に近い温度の方がより好まし
い。On the other hand, the operating temperature of the detector may be lower than the critical temperature of the superconductor to be used, but a temperature close to the critical temperature is more preferable in order to increase the detection sensitivity of the input signal.
また、信号入力部に用いる材料としては、赤外，可
視，紫外光のような光信号に対応できる光伝導性材料が
好ましい。Further, as a material used for the signal input portion, a photoconductive material capable of responding to an optical signal such as infrared, visible, or ultraviolet light is preferable.
特に、大きな光電流を生じる材料としては、InSb,Si,
GaAs,a−Si,CdS,CdSe等が好ましい。In particular, materials that generate a large photocurrent include InSb, Si,
GaAs, a-Si, CdS, CdSe and the like are preferable.
尚、かかる電流を得るには、上記光導電効果によるも
のに限らず、光起電力効果，デンバー効果等、電流発生
の可能なものならば何でも良い。In order to obtain such a current, the current is not limited to the above-described photoconductive effect, but may be anything that can generate a current, such as a photovoltaic effect and a Denver effect.
ここで、光起電力を発生する材料としては、Si,a−Si
等のPN接合、あるいはショットキー接合等がある。Here, as materials for generating photovoltaic, Si, a-Si
PN junction or Schottky junction.
［作 用］ 例えば、光伝導性材料より成る信号入力部に光を照射
すると、価電子帯の電子は励起され伝導帯に遷移する。
この伝導帯中で励起された電子が印加された電場により
移動することで光電流が生ずる。[Operation] For example, when light is irradiated to a signal input portion made of a photoconductive material, electrons in the valence band are excited and transit to the conduction band.
A photocurrent is generated by the electrons excited in the conduction band moving by the applied electric field.
一方、超伝導物質中に電流が流れると、ある一定値ま
で電圧は発生しないが、臨界電流値を越えると超伝導状
態がこわれ電圧が発生する。On the other hand, when a current flows through the superconducting material, no voltage is generated to a certain value, but when the current exceeds a critical current value, the superconducting state is broken and a voltage is generated.
本発明は、このような物理的現象を利用するものであ
る。すなわち、超伝導体の両端に臨界電流より若干少な
いバイアス電流を流しておく。この電流にさらに、例え
ば光導電効果により得られた電流を加えてやると、合計
した電流値が超伝導臨界電流より大きくなれば超伝導が
こわれ、超伝導体両端に電圧が発生することになる。The present invention utilizes such a physical phenomenon. That is, a bias current slightly smaller than the critical current is applied to both ends of the superconductor. If the current obtained by the photoconductive effect is further added to this current, if the total current value becomes larger than the superconducting critical current, the superconductivity is broken, and a voltage is generated across the superconductor. .
すなわち、上記発生した電圧を検出することにより、
入力信号を検出することができることになる。That is, by detecting the generated voltage,
The input signal can be detected.
［実施例］ 以下、実施例により本発明を詳述する。EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples.
実施例１ 第１図に本発明に基づく一実施例の概念図を示す。図
中１は超伝導体、２は電流注入要電極、３は電圧測定用
電極、４はバイアス電流印加用電源、５は光導電セル駆
動用電源、６は光導電セル、７は信号検出用電圧計であ
る。Embodiment 1 FIG. 1 shows a conceptual diagram of an embodiment based on the present invention. In the figure, 1 is a superconductor, 2 is an electrode required for current injection, 3 is an electrode for voltage measurement, 4 is a power supply for applying a bias current, 5 is a power supply for driving a photoconductive cell, 6 is a photoconductive cell, and 7 is a signal for detecting a signal. It is a voltmeter.
先ず、酸化物超伝導体YBa2Ca3O７−δ（０≦δ≦0.
5）をマグネトロンスパッタ法等によりMgO基板（不図
示）上に形成し、フォトリソグラフィー技術等により得
られた薄膜を加工する。本実施例では、酸化物超伝導体
を厚さ5000Å、幅2mm、長さ5mmの帯状とし、マイクロブ
リッジ部は幅８μｍ、長さ12μｍとした。次に、この帯
上にCr,Auの電極を４本厚さ1000Å、巾50μｍの寸法に
作成し、電流注入用電極２、電圧測定用電極３とした。First, the oxide superconductor YBa 2 Ca 3 O 7-δ (0 ≦ δ ≦ 0.
5) is formed on an MgO substrate (not shown) by a magnetron sputtering method or the like, and a thin film obtained by a photolithography technique or the like is processed. In this example, the oxide superconductor was formed into a strip having a thickness of 5000 mm, a width of 2 mm, and a length of 5 mm, and the microbridge portion was 8 μm in width and 12 μm in length. Next, four electrodes of Cr and Au were formed on this band to have a thickness of 1000 mm and a width of 50 μm, and were used as a current injection electrode 2 and a voltage measurement electrode 3.
かかる構成にした場合の超伝導体の臨界温度は88Kで
あった。この検出器の信号検出部を液体窒素中（77K）
に入れ、バイアス電流印加用電極４に10mV、光導電セル
駆動用電源５に10V印加した。ここで、光導電セル６に
光を照射しない場合、信号検出用電圧計７は0Vであり超
伝導はこわれていなかった、次に、光導電セル６にHe−
Neレーザーの5mWを照射したところ、信号検出用電圧計
７は3mVを示した。このことは、光照射により超伝導体
１に臨界電流値以上の電流が流れ、超伝導状態をこわし
たことを意味している。The critical temperature of the superconductor in such a configuration was 88K. The signal detection part of this detector is in liquid nitrogen (77K)
Then, 10 mV was applied to the bias current applying electrode 4 and 10 V was applied to the photoconductive cell driving power supply 5. Here, when the photoconductive cell 6 was not irradiated with light, the voltmeter 7 for signal detection was 0 V and the superconductivity was not broken.
When irradiated with 5 mW of Ne laser, the voltmeter 7 for signal detection showed 3 mV. This means that a current higher than the critical current value has flowed into the superconductor 1 due to the light irradiation, which has broken the superconducting state.
実施例２ 本発明の第２の実施例を第２図に示した。検出器の構
成は、信号受信部である光起電力効果を用いたPN接合部
８と検出部の一体型になっている。液体窒素中でPN接合
部８に光を照射しない場合電圧は0Vであるが、PN接合部
８に実施例１同様の光を照射すると電圧が発生した、こ
れは光起電力効果により超伝導体１に流れる電流が増大
し、超伝導状態がこわれた為である。Embodiment 2 FIG. 2 shows a second embodiment of the present invention. The configuration of the detector is an integrated type of the PN junction 8 using the photovoltaic effect as the signal receiving unit and the detecting unit. The voltage is 0 V when the PN junction 8 is not irradiated with light in liquid nitrogen. However, when the PN junction 8 is irradiated with the same light as in Example 1, a voltage is generated. This is because the current flowing in 1 increased and the superconducting state was broken.
尚、受光感度を上げる為、実施例１では光導電セル６
を用いたように、本実施例ではPN接合部に小型ヒーター
を取り付けることが可能である。In order to increase the light receiving sensitivity, the photoconductive cell 6 is used in the first embodiment.
As described above, in this embodiment, a small heater can be attached to the PN junction.
実施例３ 本発明の第３の実施例を第３図に示した。Embodiment 3 FIG. 3 shows a third embodiment of the present invention.
検出器の構成は、信号検出部の電流注入用電極２上に
光導電体薄膜９（ここでは、ａ−Siを用いた。）を積層
し、さらにその上に電極10を作製した。つまり、信号入
力部と信号検出部を一体化した構成になっている。ここ
で、実施例１と同様な測定を行ったところ、光照射の有
無と検出用電圧計の有無が対応し、光検出の可能なこと
が確かめられた。The structure of the detector was such that a photoconductor thin film 9 (here, a-Si was used) was laminated on the current injection electrode 2 of the signal detection section, and an electrode 10 was further formed thereon. That is, the signal input unit and the signal detection unit are integrated. Here, when the same measurement as in Example 1 was performed, the presence or absence of light irradiation corresponded to the presence or absence of the detection voltmeter, and it was confirmed that light detection was possible.
実施例４ 電流注入用電極2,電圧測定用電極３を金属にて作製し
た実施例１に対し、本実施例では、超伝導体（例えばYB
a2Cu3O７−δ）を用いた。本構成においても前述同様、
光検出可能なことが確認された。Embodiment 4 In contrast to Embodiment 1 in which the current injection electrode 2 and the voltage measurement electrode 3 were made of metal, in this embodiment, a superconductor (for example, YB
a 2 Cu 3 O 7-δ ) was used. Also in this configuration, as described above,
It was confirmed that light detection was possible.
［発明の効果］ 以上述べたように、本発明の信号検出器によれば、 1.従来（例えばジョセフソン接合の接合部に光を照射す
るといった場合）に比べ、光信号と検出器の位置合せが
容易，すなわち、必要とする任意の大きさの入力部（受
信部）に信号を入力することが可能となる。[Effects of the Invention] As described above, according to the signal detector of the present invention, 1. Compared with the conventional case (for example, in which a junction of a Josephson junction is irradiated with light), the optical signal and the position of the detector are compared. It is easy to match, that is, it is possible to input a signal to an input unit (reception unit) of any required size.
2.光信号入力部（受信部）の材料を適宜選択することに
より、従来に比べ広範囲の波長帯域の光信号の検出が可
能となる。2. By appropriately selecting the material of the optical signal input section (receiving section), it is possible to detect an optical signal in a wider wavelength band than in the past.
3.従来（例えばジョセフソン接合においては、検出特性
が接合特性で決定され、マルチ構成とした場合には素子
としての特性のバラツキが大きい）に比べ、再現性，信
頼性等が向上し、特性のバラツキが小さくなる。これに
より素子の集積化が容易となる。3. Reproducibility, reliability, etc. are improved compared to the conventional (for example, in the case of a Josephson junction, the detection characteristics are determined by the junction characteristics, and when the multi-configuration is used, the characteristics of the device are largely dispersed). Variation is small. This facilitates integration of elements.
といったような効果がある。There are such effects.
第１図は、本発明の信号検出器を達成するための光導電
セルを用いた検出器の構成を示す概略図である。 第２図は、本発明の信号検出器を達成するための光起電
力効果を用いた別の検出器の構成を示す概略図である。 第３図は、信号入力部と信号検出部を一体化した検出器
の構成を示す概略図である。 第４図は、従来の信号検出器の概略構成斜視図である。 １……超伝導体、２……電流注入用電極 ３……電圧測定用電極、４……バイアス電流印加電源 ５……光導電セル駆動用電源、６……光導電セル ７……信号検出用電圧計、８……PN接合部 ９……電圧測定回路系、10……電極FIG. 1 is a schematic diagram showing a configuration of a detector using a photoconductive cell for achieving the signal detector of the present invention. FIG. 2 is a schematic diagram showing the configuration of another detector using the photovoltaic effect for achieving the signal detector of the present invention. FIG. 3 is a schematic diagram showing a configuration of a detector in which a signal input unit and a signal detection unit are integrated. FIG. 4 is a schematic configuration perspective view of a conventional signal detector. DESCRIPTION OF SYMBOLS 1 ... Superconductor, 2 ... Electrode for current injection 3 ... Electrode for voltage measurement, 4 ... Power supply for bias current application 5 ... Power supply for driving photoconductive cell, 6 ... Photoconductive cell 7 ... Signal detection Voltmeter, 8 PN junction 9 Voltage measurement circuit, 10 Electrodes
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭64−50486（ＪＰ，Ａ) 特開 昭64−86575（ＪＰ，Ａ) 特開 平１−184423（ＪＰ，Ａ) 特開 平３−37527（ＪＰ，Ａ) ────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-64-50486 (JP, A) JP-A-64-86575 (JP, A) JP-A-1-184423 (JP, A) JP-A-3- 37527 (JP, A)
Claims (3)
部と、該発生電流を注入することによって光信号を検出
する超伝導体を用いた信号検出部とを少なくとも有する
信号検出器であって、前記信号検出部は、該信号入力部
とは電気的に接続されているが離間して配置されてお
り、該発生電流の注入により該超伝導体に該超伝導体の
臨界電流値を越える電流を流して該超伝導体の両端に発
生する電圧を検出することで光信号を検出するものであ
ることを特徴とする信号検出器。1. A signal detector comprising at least a signal input section in which a current is generated by input of an optical signal, and a signal detector using a superconductor for detecting the optical signal by injecting the generated current. The signal detection unit is electrically connected to the signal input unit but is arranged at a distance from the signal input unit. The signal detection unit exceeds the critical current value of the superconductor due to the injection of the generated current. A signal detector for detecting an optical signal by detecting a voltage generated at both ends of the superconductor by flowing a current.
セフソン接合を用いたことを特徴とする請求項１記載の
信号検出器。2. The signal detector according to claim 1, wherein a micro-bridge type Josephson junction is used for the signal detector.
とを特徴とする請求項１又は２記載の信号検出器。3. The signal detector according to claim 1, wherein a photoconductive material is used for the signal input section.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1180286A JP2737007B2 (en) | 1989-07-14 | 1989-07-14 | Signal detector |
| EP93203066A EP0590738B1 (en) | 1989-07-05 | 1990-07-04 | Light detecting device and light detecting method using a superconductor |
| EP90307302A EP0407166B1 (en) | 1989-07-05 | 1990-07-04 | Light detecting device and light detection method |
| DE69031501T DE69031501T2 (en) | 1989-07-05 | 1990-07-04 | Device and method for measuring light using a superconductor |
| DE69009109T DE69009109T2 (en) | 1989-07-05 | 1990-07-04 | Device and method for measuring light. |
| US07/548,212 US5155093A (en) | 1989-07-05 | 1990-07-05 | Light detecting device and light detecting method using a superconnector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1180286A JP2737007B2 (en) | 1989-07-14 | 1989-07-14 | Signal detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0346521A JPH0346521A (en) | 1991-02-27 |
| JP2737007B2 true JP2737007B2 (en) | 1998-04-08 |
Family
ID=16080557
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1180286A Expired - Fee Related JP2737007B2 (en) | 1989-07-05 | 1989-07-14 | Signal detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2737007B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0837107A (en) * | 1994-07-22 | 1996-02-06 | Tdk Corp | Dust core |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6486575A (en) * | 1987-06-17 | 1989-03-31 | Hitachi Ltd | Superconducting device |
| JPS6450486A (en) * | 1987-08-20 | 1989-02-27 | Mitsubishi Electric Corp | Optical switch element |
| JPH01184423A (en) * | 1988-01-18 | 1989-07-24 | Fujitsu Ltd | Superconducting photodetector |
-
1989
- 1989-07-14 JP JP1180286A patent/JP2737007B2/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| JPH0346521A (en) | 1991-02-27 |
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