JPH0785036B2 - Optical waveform temperature sensor - Google Patents
Optical waveform temperature sensorInfo
- Publication number
- JPH0785036B2 JPH0785036B2 JP61060044A JP6004486A JPH0785036B2 JP H0785036 B2 JPH0785036 B2 JP H0785036B2 JP 61060044 A JP61060044 A JP 61060044A JP 6004486 A JP6004486 A JP 6004486A JP H0785036 B2 JPH0785036 B2 JP H0785036B2
- Authority
- JP
- Japan
- Prior art keywords
- optical
- electric field
- substrate
- temperature sensor
- region
- 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 - Fee Related
Links
Landscapes
- Measuring Temperature Or Quantity Of Heat (AREA)
- Radiation Pyrometers (AREA)
Description
【発明の詳細な説明】 〔概要〕 高感度な温度計を実現するために、焦電効果によって生
じた電荷がつくる電界中に１つの光導波路を設け、温度
変化によって電界強度が変化することを利用して、電界
中の光導波路の屈折率を変化させ、該電界の影響を受け
ない領域にもう１つの光導波路を設け、両光導波路から
出射する光を合波して検知し、温度を検出する。DETAILED DESCRIPTION OF THE INVENTION [Outline] In order to realize a highly sensitive thermometer, one optical waveguide is provided in an electric field generated by electric charges generated by the pyroelectric effect, and it is possible to change the electric field strength by temperature change. Utilizing this, the refractive index of the optical waveguide in the electric field is changed, another optical waveguide is provided in a region that is not affected by the electric field, and the light emitted from both optical waveguides is combined and detected to detect the temperature. To detect.
本発明は、光導波路の屈折率が温度によって変化するこ
とを利用して、光学的に測温する光導波形温度センサに
関する。The present invention relates to an optical waveform temperature sensor that optically measures temperature by utilizing the fact that the refractive index of an optical waveguide changes with temperature.
第４図は従来の光導波形温度センサを示す図である。基
板１上には、入射路２と出射路３が形成されており、入
射路２と出射路３間は、２本の並列な導波路４、５によ
って２つにＹ分岐している。そして片方の導波路４が他
方の導波路５よりわずかに長くなっている。FIG. 4 is a diagram showing a conventional optical waveform temperature sensor. An entrance path 2 and an exit path 3 are formed on the substrate 1, and the entrance path 2 and the exit path 3 are bifurcated into two by two parallel waveguides 4 and 5. The one waveguide 4 is slightly longer than the other waveguide 5.
入射路２から、半導体レーザLDにより波長の安定した直
線偏光を入射すると、２つの導波路４、５に分岐して伝
播し、出射路３で合波して出射する。このとき、導波路
４と５の長さが異なるために、両導波路４、５に伝播し
てきた光は位相差をもち、出射路３で干渉し合い、位相
差に対応した光強度で出射する。When linearly polarized light having a stable wavelength is incident from the incident path 2 by the semiconductor laser LD, the linearly polarized light is branched and propagated to the two waveguides 4 and 5, and is combined and emitted at the emission path 3. At this time, since the lengths of the waveguides 4 and 5 are different, the lights propagating to the both waveguides 4 and 5 have a phase difference and interfere with each other in the emission path 3 to emit with the light intensity corresponding to the phase difference. To do.
導波路２…５は、温度変化によって屈折率が変化するた
め、ある温度T1における屈折率n1、温度T2における屈折
率をn2とすると、導波路４と５を伝播する光は、温度T1
においてはn1（l1−l2）の位相差を有し、温度T2におい
てはn2（l1−l2）の位相差を有する。したがって温度変
化によって各導波路の屈折率が変化することで、出射路
３からの出射光の光強度が変化する。これをフォトダイ
オードＤ等で検出することで、温度を測定することがで
きる。Since the refractive indices of the waveguides 2 ... 5 change due to temperature changes, assuming that the refractive index n1 at a certain temperature T1 and the refractive index n2 at a certain temperature T2 are n2 and the light propagating through the waveguides 4 and 5, the temperature T1
Has a phase difference of n1 (l1-l2), and has a phase difference of n2 (l1-l2) at temperature T2. Therefore, since the refractive index of each waveguide changes due to the temperature change, the light intensity of the light emitted from the emission path 3 changes. The temperature can be measured by detecting this with the photodiode D or the like.
このように温度によって屈折率が変化することを利用し
ているが、この効果は小さいので、高感度にするには素
子長を長くしなければならず、大型な装置となる。本発
明の技術的課題は、従来の光導波形温度センサにおける
このような問題を解消し、小型でかつ高感度の光導波形
温度センサを実現することにより、各種装置のインテリ
ジェント化に即応可能とすることにある。The fact that the refractive index changes according to the temperature is used in this way, but this effect is small, so the element length must be lengthened in order to achieve high sensitivity, and this results in a large device. The technical problem of the present invention is to solve such problems in the conventional optical waveform temperature sensor, and to realize a compact and highly sensitive optical waveform temperature sensor, thereby making it possible to immediately respond to intelligentization of various devices. It is in.
第１図は本発明による光導波形温度センサの基本原理を
説明する断面図である。６は焦電効果と電気光学効果を
もつ基板であり、表面に電荷が現れ、かつ温度変化によ
って分極効果が変化する。11は基板６の一面に設けられ
た絶縁層、12は基板６および絶縁層11の外周を囲むよう
に設けられた金属膜であるが、その絶縁層上の一部には
中断部13が形成されている。このため、中断部13に対応
する位置は基板６から発生する電界の密度の高い領域７
となり、中断部13から外れた位置は電界の密度の低い領
域８となる。そして電界密度の高い領域７に光導波路９
が設けられ、電界密度の低い領域８に、もう１つの光導
波路10が形成されている。そして両光導波路９、10は並
列に配置され、それぞれの一端は１つの入射路に接続さ
れ、他端は１つの出射路に接続される。FIG. 1 is a sectional view for explaining the basic principle of the optical waveform temperature sensor according to the present invention. Reference numeral 6 denotes a substrate having a pyroelectric effect and an electro-optical effect, electric charges appear on the surface, and the polarization effect changes due to temperature change. Reference numeral 11 is an insulating layer provided on one surface of the substrate 6, and 12 is a metal film provided so as to surround the outer peripheries of the substrate 6 and the insulating layer 11. An interrupted portion 13 is formed on a part of the insulating layer. Has been done. Therefore, the position corresponding to the interruption portion 13 is located in the region 7 where the electric field density generated from the substrate 6 is high.
Therefore, the position deviated from the interrupted portion 13 becomes the region 8 where the electric field density is low. Then, the optical waveguide 9 is formed in the region 7 where the electric field density is high.
, And another optical waveguide 10 is formed in the region 8 having a low electric field density. Both optical waveguides 9 and 10 are arranged in parallel, one end of each is connected to one incident path, and the other end is connected to one outgoing path.
基板６の焦電効果によって発生した分極電荷による電界
密度の高い領域に光導波路９が有るため、温度変化によ
って電界密度が変化すると、今度は電気光学効果によっ
て光導波路９中の屈折率が変化する。もう１つの光導波
路10は、電界密度の低い領域８に設けられているので、
温度変化による電界密度の変化は少なく、したがって屈
折率の変化も小さい。そのため、２つの光導波路９、10
に入射した光が、出射路から出射する際に、片方の光導
波路９の屈折率が温度変化によって変化することで、両
光導波路９、10からの出射光の位相差が変化する。その
結果、出射光を光電素子で検出することにより、温度を
測定できる。また基板６の結晶の焦電効果および電気光
学効果が大きいため、小型な素子で高感度の光導波形温
度センサを実現できる。Since the optical waveguide 9 exists in a region where the electric field density is high due to the polarization charge generated by the pyroelectric effect of the substrate 6, when the electric field density changes due to temperature change, the refractive index in the optical waveguide 9 changes due to the electro-optical effect. . Since the other optical waveguide 10 is provided in the region 8 where the electric field density is low,
A change in electric field density due to a change in temperature is small, and thus a change in refractive index is also small. Therefore, the two optical waveguides 9 and 10
When the light incident on the light exits from the exit path, the refractive index of one of the optical waveguides 9 changes due to the temperature change, so that the phase difference between the light output from the both optical waveguides 9 and 10 changes. As a result, the temperature can be measured by detecting the emitted light with the photoelectric element. Further, since the crystal of the substrate 6 has a large pyroelectric effect and electro-optical effect, a highly sensitive optical waveform temperature sensor can be realized with a small element.
次に本発明による光導波形温度センサが実際上どのよう
に具体化されるかを実施例で説明する。第２図は本発明
による光導波形温度センサの断面図、第３図は同温度セ
ンサの斜視図である。焦電効果および電気光学効果を有
する基板６としては、Ｚ−cut LiNbO3が適しているが、
LiTaO3（リチウムタンタレート）なども有効である。こ
の基板６上に、Tiを1000℃程度の温度で熱拡散すること
で、２本の光導波路９、10が平行に形成されている。基
板６上において、両光導波路９、10の一端は、１本の入
射路２に接続され、他端は出射路３に接続されること
で、Ｙ分岐を用いたマッハツェンダー干渉計を構成して
いる。そして光導波路９、10側の面に、絶縁層を形成す
るために、SiO2を蒸着した絶縁膜11aが形成されてい
る。この絶縁膜11aおよび基板６の外周を囲むように、
金属膜12を蒸着などによって形成するが、光導波路９と
対向する領域だけをマスクして蒸着することで、中断部
13が形成されている。Next, practical examples of how the optical waveform temperature sensor according to the present invention is embodied will be described. FIG. 2 is a sectional view of the optical waveform temperature sensor according to the present invention, and FIG. 3 is a perspective view of the temperature sensor. As the substrate 6 having the pyroelectric effect and the electro-optical effect, Z-cut LiNbO 3 is suitable,
LiTaO 3 (lithium tantalate) is also effective. Two optical waveguides 9 and 10 are formed in parallel on this substrate 6 by thermally diffusing Ti at a temperature of about 1000 ° C. On the substrate 6, one end of each of the optical waveguides 9 and 10 is connected to one entrance path 2 and the other end is connected to the exit path 3 to form a Mach-Zehnder interferometer using a Y-branch. ing. An insulating film 11a formed by depositing SiO 2 is formed on the surface of the optical waveguides 9 and 10 to form an insulating layer. To surround the outer periphery of the insulating film 11a and the substrate 6,
The metal film 12 is formed by vapor deposition or the like, but by interrupting the vapor deposition while masking only the region facing the optical waveguide 9,
13 are formed.
このように、基板６および絶縁膜11aの外周を金属膜12
で囲むことで、第１図に示すように、基板６の表面に生
じる電荷により、金属膜12に逆極性の電荷が誘起され
る。そのため、電界は基板６の面と金属膜12との間の絶
縁膜11a中に生じる。ところが金属膜の中断部13では、
基板６表面の電荷のつくる電界は、第１図に示すように
基板６中の光導波路９中を通り、電界密度の高い領域７
が形成される。In this way, the metal film 12 is formed on the outer periphery of the substrate 6 and the insulating film 11a.
As shown in FIG. 1, the electric charges generated on the surface of the substrate 6 induce the electric charges of the opposite polarity in the metal film 12, as shown in FIG. Therefore, an electric field is generated in the insulating film 11a between the surface of the substrate 6 and the metal film 12. However, in the interruption part 13 of the metal film,
The electric field generated by the charges on the surface of the substrate 6 passes through the optical waveguide 9 in the substrate 6 as shown in FIG.
Is formed.
このように、Ｙ分岐後の２本の導波路のうち１本だけ
が、温度変化により電界密度が変化し、電気光学効果を
介して屈折率が変わるようにしている。そのため、両光
導波路９、10から出射し合波した光の強度を検知するこ
とで、温度測定が可能となる。As described above, only one of the two waveguides after the Y-branch changes the electric field density due to the temperature change, and the refractive index changes via the electro-optic effect. Therefore, the temperature can be measured by detecting the intensity of the light emitted from both optical waveguides 9 and 10 and combined.
以上のように本発明によれば、２本のＹ分岐光導波路
９、10のうち、片方の光導波路９のみ、焦電効果および
電気光学効果を有する基板の電界密度の高い領域に設
け、温度変化によって生ずる焦電効果による電荷からの
電界を利用して光を変調する構成になっているので、こ
の電荷からの電界が極めて強く、微少な温度変化をも検
知でき、焦電効果および電気光学効果が大きい。そのた
め、基板６を大型化しなくても充分感度を得ることがで
き、信頼性の高い光導波形温度センサを実現可能とな
る。As described above, according to the present invention, of the two Y-branch optical waveguides 9 and 10, only one optical waveguide 9 is provided in a region having a high electric field density of a substrate having a pyroelectric effect and an electro-optical effect, and The light is modulated by using the electric field from the electric charge due to the pyroelectric effect caused by the change, so the electric field from the electric charge is extremely strong, and even a slight temperature change can be detected. Great effect. Therefore, sufficient sensitivity can be obtained without increasing the size of the substrate 6, and a highly reliable optical waveform temperature sensor can be realized.
第１図は本発明による光導波形温度センサの基本原理を
説明する断面図、第２図は本発明による光導波形温度セ
ンサの実施例を示す断面図、第３図は同実施例センサの
斜視図、第４図は従来の光導波形温度センサの平面図で
ある。 図において、６は基板、７は電界密度の高い領域、８は
電界密度の低い領域、９、10は光導波路、11は絶縁層、
12は金属膜、13は中断部をそれぞれ示す。FIG. 1 is a sectional view for explaining the basic principle of an optical waveform temperature sensor according to the present invention, FIG. 2 is a sectional view showing an embodiment of the optical waveform temperature sensor according to the present invention, and FIG. 3 is a perspective view of the same embodiment sensor. FIG. 4 is a plan view of a conventional optical waveform temperature sensor. In the figure, 6 is a substrate, 7 is a high electric field density region, 8 is a low electric field density region, 9 and 10 are optical waveguides, 11 is an insulating layer,
Reference numeral 12 indicates a metal film, and 13 indicates an interrupted portion.
Claims (1)
の一面に絶縁層（11）を設けるとともに、これら基板
（６）および絶縁層（11）の外周に金属膜（12）を設
け、かつ該金属膜（12）には前記絶縁層（11）上で中断
部（13）を形成することで、該基板（６）から発生する
電界の密度を該中断部（13）に対応する位置で高くした
領域（７）と、電界の弱い領域（８）を形成すること、 前記基板（６）に２つの光導波路（９）（10）を設け、
その片方の光導波路（９）は、前記電界密度の高い領域
（７）に配置し、他方の光導波路（10）は、前記電界密
度の低い領域（８）に配置すること、 両光導波路（９）（10）の一端同士を１つの入射路に接
続し、他端同士は１つの出射路に接続することを特徴と
する光導波形温度センサ。1. A substrate (6) having a pyroelectric effect and an electro-optical effect.
An insulating layer (11) is provided on one surface, and a metal film (12) is provided on the outer periphery of the substrate (6) and the insulating layer (11), and the metal film (12) is formed on the insulating layer (11). By forming the interrupted portion (13) with the region (7) where the density of the electric field generated from the substrate (6) is increased at the position corresponding to the interrupted portion (13), and the region (8) where the electric field is weak. Forming two optical waveguides (9) and (10) on the substrate (6),
One of the optical waveguides (9) is arranged in the region (7) having a high electric field density, and the other optical waveguide (10) is arranged in the region (8) having a low electric field density. 9) An optical waveform temperature sensor, characterized in that one end of (10) is connected to one incident path and the other end is connected to one exit path.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61060044A JPH0785036B2 (en) | 1986-03-18 | 1986-03-18 | Optical waveform temperature sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61060044A JPH0785036B2 (en) | 1986-03-18 | 1986-03-18 | Optical waveform temperature sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62215836A JPS62215836A (en) | 1987-09-22 |
| JPH0785036B2 true JPH0785036B2 (en) | 1995-09-13 |
Family
ID=13130681
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61060044A Expired - Fee Related JPH0785036B2 (en) | 1986-03-18 | 1986-03-18 | Optical waveform temperature sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0785036B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4770449B2 (en) * | 2005-12-20 | 2011-09-14 | 住友電気工業株式会社 | Optical waveguide device, temperature measuring device, and temperature measuring method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5655825A (en) * | 1979-10-12 | 1981-05-16 | Matsushita Electric Ind Co Ltd | Optical type temperature sensor |
| JPS56112608A (en) * | 1980-02-12 | 1981-09-05 | Toshiba Corp | Optical sensing device |
| JPS60170723A (en) * | 1984-02-15 | 1985-09-04 | Yokogawa Hokushin Electric Corp | Optical transducer |
-
1986
- 1986-03-18 JP JP61060044A patent/JPH0785036B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62215836A (en) | 1987-09-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |