CN109580035B - Sapphire optical fiber high-temperature sensor with high fringe visibility and temperature measuring method thereof - Google Patents
Sapphire optical fiber high-temperature sensor with high fringe visibility and temperature measuring method thereof Download PDFInfo
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Abstract
The invention discloses a sapphire optical fiber Fabry-Perot high-temperature sensor with high stripe contrast, which comprises a sapphire wafer (1), a sapphire ferrule (2) and sapphire-quartz optical fibers forming optical signal transmission waveguides in a high-temperature region and a normal-temperature region, wherein light emitted by an LED light source (9) enters a high-temperature sensor (8) and is emitted from the end surface (15) of the sapphire optical fiber, and the diffused light irradiates a first reflecting surface (16) of the sapphire wafer (1) to be reflected for the first time; the rest part of the light is transmitted to a second reflection surface (17) of the wafer to generate second reflection; the first beam of reflected light (11) and the first beam of reflected light (12) generated on the two surfaces of the Fabry-Perot interference cavity are coupled into the sapphire optical fiber (4) to form Fabry-Perot double-optical-fiber interference signals, and the interference signals are demodulated through a spectrum method to obtain Fabry-Perot optical path difference so as to reversely push the temperature. The invention greatly improves the fringe visibility of interference signals of the Fabry-Perot sensor and simultaneously improves the temperature sensitivity and temperature measurement resolution of the sensor.
Description
Technical Field
The invention relates to the field of optical fiber sensing, in particular to a sapphire optical fiber high-temperature sensor which has an optical fiber coupling beam splitting design and high fringe visibility and can realize extreme temperature monitoring in a complex test environment.
Background
With the rapid development of aerospace and internal combustion engine industries, higher requirements are put forward on high-temperature monitoring technology under extreme conditions. The traditional electric sensor can not meet the measurement requirement under the severe environment with electric conduction, flammability, explosiveness and strong corrosivity. The high-temperature sensing technology based on the sapphire optical fiber plays an important role in the field of high-temperature monitoring due to the characteristics of oxidation resistance, high precision, electromagnetic interference resistance and the like.
In recent years, various types of sapphire fiber optic sensors have been proposed to achieve extremely high temperature (1000 ℃ or higher) measurements, such as sapphire fiber grating type, black body radiation type, and fabry-perot type sensors. However, the sapphire fiber grating type sapphire fiber sensor needs to be etched by an expensive femtosecond laser, is high in manufacturing cost, and is limited by the large numerical aperture of the sapphire fiber, serious in mode interference and low in measurement accuracy compared with other methods. The blackbody radiation type sapphire optical fiber sensor has good temperature measurement precision in a high-temperature region (600-; however, the radiation power of the low-temperature section is obviously reduced, the signal-to-noise ratio is extremely rapidly attenuated below 600 ℃, the temperature measurement range is limited, and the temperature monitoring device can only be used for temperature monitoring of the high-temperature section. The Fabry-Perot sapphire optical fiber sensor has an extremely wide measuring range, can be flexibly designed according to requirements, is manufactured by adopting a traditional grinding process, can be produced in batches, and has low cost, so that the Fabry-Perot sapphire optical fiber sensor has a wide application range. However, since the sapphire fiber is manufactured by adopting a crystal growth method and is limited in length, remote sensing is generally achieved internationally by welding the sapphire fiber and the quartz fiber, that is, the sapphire fiber is used in a high-temperature region, and the quartz fiber is used in a normal-temperature region to lengthen the transmission distance. In the heterogeneous optical fiber coupling process, in order to achieve the coupling efficiency as high as possible, the sapphire optical fiber and the quartz optical fiber end face need to be polished to reduce the scattering loss of the fusion point. The method is beneficial to improving the optical energy coupling rate, but the section of the precisely polished optical fiber can introduce a background reflected light in a transmission optical path, and the background reflected light is superposed in an output signal of the sensor, so that the visibility of interference fringes of the sensor is reduced, and further the demodulation precision is influenced. Meanwhile, in order to ensure high fringe visibility, the requirement on the sensor manufacturing process is high, and the wafer and the end face of the optical fiber must be strictly parallel, which puts a high requirement on the precision of clamping and fixing the original.
Disclosure of Invention
Aiming at the defect that the traditional sapphire optical fiber sensor cannot achieve both the fringe contrast and the coupling quality, the invention provides the sapphire optical fiber high-temperature sensor with high fringe visibility and the temperature measuring method thereof.
The invention relates to a sapphire optical fiber Fabry-Perot high-temperature sensor with high stripe contrast, which comprises a sapphire wafer 1, a sapphire ferrule 2 and sapphire-quartz optical fibers forming optical signal transmission waveguides of a high-temperature region and a normal-temperature region; the sapphire wafer 1 and the sapphire ferrule 2 are tightly attached to each other in circular section and are fixed by high-temperature ceramic glue 3; the sapphire-quartz optical fiber is formed by welding a sapphire optical fiber 4 and a flattened quartz optical fiber 5 through an optical fiber welding point 6 between end faces; the sapphire-quartz optical fiber is inserted into the middle hole of the sapphire ferrule 2 from one end of the sapphire optical fiber 4, and the optimal sensing signal position between the sapphire optical fiber 4 and the sapphire wafer 1 is fixed by using high-temperature ceramic glue 3; the sapphire-quartz optical fiber is formed by welding a sapphire optical fiber 4 and a flattened quartz optical fiber 5 through an optical fiber welding point 6 between end faces, and an input waveguide 21 and an output waveguide 22 are formed; the sapphire-quartz optical fiber is inserted into the middle hole of the sapphire ferrule 2 from one end of the sapphire optical fiber 4, and the optimal sensing signal position between the sapphire optical fiber 4 and the sapphire wafer 1 is fixed by using high-temperature ceramic glue 3; the sapphire-quartz optical fiber is respectively connected with an LED light source 9 and a spectrometer 10 from one end of a quartz optical fiber 5 through an optical fiber jumper 7, so that the shunt transmission of an input waveguide 21 and an output waveguide 22 is realized, and finally an interference signal is transmitted to the spectrometer; the two reflecting surfaces of the sapphire wafer 1 form a Fabry-Perot interference cavity, and the diffused light irradiates a first reflecting surface 16 of the sapphire wafer 1 to be reflected for the first time to form a first beam of reflected light 11; the rest part of light is transmitted to the second reflection surface 17 of the sapphire wafer 1 to be reflected for the second time to form a second beam of reflection light 12 carrying optical path difference information, the input waveguide 21 projects the original light signal emitted by the LED light source 9 to the sapphire wafer 1, and the output waveguide 22 receives the interference signals reflected back from the two reflection surfaces of the sapphire wafer 1, so that the double-optical-path separation of input signal light and output signal light is realized
The invention relates to a temperature measuring method realized by a sapphire optical fiber Fabry-Perot high-temperature sensor with high stripe contrast, which comprises the following steps:
connecting the high-temperature sensor 8 in a working state with an LED light source 9 and a spectrometer 10 through an optical fiber jumper 7; light emitted by the LED light source 9 enters the high-temperature sensor 8 through the optical fiber jumper 7, is emitted from the sapphire optical fiber end face 15 through the heterogeneous optical fiber fusion point 6, and is irradiated to the first reflecting face 16 of the sapphire wafer 1 to be reflected for the first time to form a first beam of reflected light 11; the rest part of the light is transmitted to the second reflection surface 17 of the wafer to be reflected for the second time, and a second beam of reflected light 12 carrying optical path difference information is formed; the first beam of reflected light 11 and the first beam of reflected light 11 generated on the two surfaces of the Fabry-Perot interference cavity are coupled into the sapphire optical fiber 4 to be output, so that a Fabry-Perot dual-optical-fiber interference signal 18 is formed, namely the optical path difference between the two beams of reflected light of the first beam of reflected light 11 and the second beam of reflected light 12 changes along with the first beam of reflected light and the second beam of reflected light, and the interference signal changes; the interference signal 18 is transmitted back to the spectrometer 10 through the sapphire optical fiber 4, the quartz optical fiber 5 and the optical fiber jumper 7;
the interference spectrum signal collected from the spectrometer is represented as:
wherein k is 2 pi/λ; i isB(k) Representing the amount of DC background, S, in the interference spectrum signal1(k),S2(k) Representing two reflected lights received by the optical fiber, delta representing the optical path difference between the two coherent lights,
representing the initial optical path difference, L, n representing the thickness and refractive index of the sapphire wafer;
when the temperature of the environment changes, the thickness and the material refractive index of the sapphire wafer change:
the formula of the change of the refractive index of the sapphire wafer with the temperature is expressed as follows:
n(T)850nm＝a0+a1T+a2T2
wherein T is temperature in centigrade, n (T)850nmThe refractive index of the sapphire wafer material is below 850 nm;
the thermal expansion function of the sapphire material along the C-axis is expressed as:
L(T)＝[b0+b1T+b2T2+b3T3]×L0
wherein T represents a Kelvin temperature, L (T) represents a temperature T and an initial length L0An initial length under conditions;
as can be seen from the above, the optical path difference Δ is 2n (T) l (T) and is expressed by a fifth-order polynomial relationship of the temperature T, and the fabry-perot optical path difference is obtained by demodulating the interference signal by the spectroscopic method, and the temperature at which the sapphire wafer is located is further reversely returned.
In the step of obtaining the information of the Fabry-Perot optical path difference by demodulating the interference signal through the spectrum method, the demodulation precision depends on the acquisition resolution of the interference spectrum and the accurate searching of the position of the fringe peak value: the spectrum collection resolution is determined by the spectrometer resolution, and the peak position is accurately found to be closely related to the visibility of the interference spectrum fringe, so that in practical measurement, the visibility of the interference spectrum fringe is further expressed as:
wherein FVIndicating the visibility of the interference fringes in the background light signal.
The invention has the following positive effects:
1. by applying the optical fiber coupling beam splitting model, reflected background light introduced by the end face of the input optical fiber and the fusion point of the heterogeneous optical fiber is filtered from the output signal, so that the input optical signal and the output interference signal are fully stripped, the influence of a direct current background item and scattered light at the fusion point of the heterogeneous optical fiber on the interference signal is eliminated, the fringe visibility of the interference signal of the Fabry-Perot sensor is greatly improved, the mutual restriction of the coupling quality of the fusion point and the high fringe visibility is overcome, and the temperature sensitivity and the temperature measurement resolution of the sensor are improved;
2. by optimizing the optical path structure of the Fabry-Perot sensor, direct-current background light and scattered interference light in an output signal are fundamentally filtered, the stability and the resolution of the sensor in a severe environment are improved, and an effective means is provided for high-temperature monitoring under the condition of extremely high ambient light influence;
3. when the measured temperature rises and the influence of ambient stray light on the sensor signal is large, the higher visibility of the fringes can improve the noise tolerance of accurate peak identification. The method has important significance for improving the accuracy and the resolution of the sensor in a complex measurement environment.
Drawings
FIG. 1 is a schematic structural diagram of a sapphire optical fiber Fabry-Perot high-temperature sensor with high fringe visibility according to the invention;
FIG. 2 is a schematic diagram of the optical path transmission of the sapphire optical fiber Fabry-Perot high-temperature sensor with high fringe visibility according to the invention;
FIG. 3 is a schematic diagram (a) of a spatial light path expanding and a fiber coupling model of a high-fringe visibility sapphire fiber Fabry-Perot high-temperature sensor head part according to the invention;
FIG. 4 is a diagram of a laboratory testing system of the sapphire optical fiber Fabry-Perot high-temperature sensor with high fringe visibility according to the invention
FIG. 5 is a comparison laboratory test result of the high-fringe visibility sapphire optical fiber Fabry-Perot high-temperature sensor of the present invention and a conventional single optical fiber Fabry-Perot high-temperature sensor, wherein (a) is temperature measurement resolution, and (b) is measurement error;
FIG. 6 is a graph of the results of a comparison test of temperature measurement stability of the high-fringe visibility sapphire fiber Fabry-Perot high-temperature sensor of the present invention and a conventional single fiber sensor.
In the figure: 1. sapphire wafer, 2, sapphire ferrule, 3, high-temperature ceramic cement, 4, sapphire optical fiber, 5, quartz optical fiber, 6, heterogeneous optical fiber fusion point, 7, optical fiber jumper, 8, high-temperature sensor, 9, LED light source, 10, spectrometer, 11, first beam of reflected light, 12, second beam of reflected light, 13, input light beam, 14, fusion point scattered light, 15, sapphire optical fiber end face, 16, first reflection surface, 17, second reflection surface, 18, interference signal, 19, direct current background light, 20, high-temperature muffle furnace, 21, input waveguide, 22 and output waveguide.
Detailed Description
The technical solution of the present invention will be described in further detail with reference to examples.
As shown in fig. 1, the structure of the sensor comprises a sapphire wafer 1, a sapphire ferrule 2, a sapphire optical fiber 4 and a quartz optical fiber 5; the sapphire wafer 1 and the sapphire ferrule 2 are tightly attached to each other in circular cross section, fixed through high-temperature ceramic glue 3, and the two end faces of the sapphire optical fiber 3 are ground by an optical fiber grinding machine to achieve certain degree of finish. And then fusion-jointed with the end face of the cut quartz optical fiber 5 to construct optical signal transmission waveguides in a high-temperature region and a normal-temperature region. The end faces of two welded sapphire-quartz optical fibers are aligned and closed, a middle hole of the sapphire ferrule 2 is inserted from one end of the sapphire optical fiber 4, and the end faces of the two quartz optical fibers 5 are respectively connected with an LED light source 9 and a spectrometer 10 through optical fiber jumpers 7, so that the shunt transmission of an input waveguide and an output waveguide is realized. The relative position between the two sapphire optical fibers 4 and the sapphire wafer 1 is realized through a precise displacement control table, the best position for sensing the signal is found, and the sapphire optical fibers are fixed by using high-temperature ceramic glue 3. Two reflecting surfaces of the sapphire wafer 1 form a Fabry-Perot interference cavity which is used as a temperature sensitive element to realize sensing;
when the sensor works, the high-temperature sensor 8 is connected with the LED light source 9 and the spectrometer 10 through the optical fiber jumper 7. Light emitted by the LED light source 9 enters the sensor through the optical fiber jumper 7, is emitted from the end face 15 of the sapphire optical fiber through the fusion point 6 of the heterogeneous optical fiber, and is irradiated to the first reflecting face 16 of the sapphire wafer 1 to be reflected for the first time to form a first beam of reflected light 11; the rest part of the light is transmitted to the second reflection surface 17 of the wafer to be reflected for the second time, and a second beam of reflected light 12 carrying optical path difference information is formed; the first beam and the second beam of reflected light 11 and 12 generated by the two surfaces of the Fabry-Perot wafer are coupled into the output sapphire optical fiber to form Fabry-Perot double-optical-fiber interference. The interference signal 18 is transmitted back to the spectrometer 10 through the sapphire optical fiber 4, the quartz optical fiber 5, and the optical fiber jumper 7. When the ambient temperature of the sensor changes, the thickness of the temperature sensing wafer and the refractive index of the material change, and the optical path difference between the two beams of reflected light changes, so that the interference signal changes. The Fabry-Perot optical path difference information can be obtained by demodulating the interference signal. Further reversely pushing back the temperature information of the sapphire wafer;
the interference spectrum signal collected from the spectrometer is represented as:
wherein k is 2 pi/λ; i isB(k) The direct current background quantity in the signal is represented and mainly comprises fusion point scattering and sapphire optical fiber end face background reflection; s1(k),S2(k) Two beams of reflected light received by the optical fiber; delta represents the optical path difference between the two beams of coherent light, namely 2 nL;
indicating the initial optical path difference. Here, since the thickness L and the refractive index n of the fabry perot wafer are both functions of temperature, Δ represents a function of temperature.
The formula of the sapphire Fabry-Perot wafer along with the temperature change is shown as follows:
n(T)850nm＝a0+a1T+a2T2
wherein T represents the temperature in centigrade, n (T)850nmThe refractive index of the sapphire wafer material at 850nm is expressed the thermal expansion function of the sapphire material along the C-axis can be expressed as:
L(T)＝[b0+b1T+b2T2+b3T3]×L0
wherein T represents a Kelvin temperature, L (T) represents a temperature T and an initial length L0Initial length under conditions. As can be seen from the above, the optical path difference Δ is 2n (T) l (T) and can be expressed as a fifth-order polynomial relationship of the temperature T. Therefore, the measurement target temperature can be reversely deduced by measuring the optical path difference.
The accuracy of the spectral method for demodulating the interference optical path difference depends on the acquisition resolution and the fringes of the interference spectrumAccurate finding of peak position. The spectrum acquisition resolution is determined by the resolution of a spectrometer, and the accurate peak position searching is closely related to the visibility of interference spectrum fringes. Fringe visibility FVIs commonly used to represent the visibility of interference fringes in a background light signal and is defined as follows:
in practical measurements, the fringe visibility can be further expressed as:
because of S1(k),S2(k) The change of the optical fiber is relatively small, the direct current background light I in the interference signal of the receiving end can be effectively filtered through the optical fiber optical path shunt transmission and the reasonable application of the coupling technologyB(k) And the visibility of interference fringes is obviously improved. According to the white light Fabry-Perot optical path difference demodulation principle, the high fringe visibility is beneficial to improving the peak searching precision, and further the temperature measurement precision and the temperature measurement resolution are improved.
Example 1:
as shown in fig. 4, the wide spectrum light output by the LED broadband light source 9 is guided into the high temperature sensor 8 through the optical fiber jumper 7, the multimode silica fiber 5, the heterogeneous fiber fusion point 6, and the sapphire fiber 4, and the reflected signal light is received by the spectrometer through the sapphire fiber 4, the heterogeneous fiber fusion point 6, the silica fiber 5, and the optical fiber jumper 7 in sequence. The high temperature sensor 8 is placed in the tubular cavity of the high temperature muffle 20, and a temperature variable is applied to the sensor by adjusting the temperature in the muffle cavity, wherein the measurement range is 100-. The change of the temperature causes the optical refractive index and the material expansion and contraction of the sapphire wafer 1, and the change of the Fabry-Perot optical path difference is caused, and the optical path difference of the sensor under the measurement environment temperature can be obtained by calculating the interference spectrum information received by the spectrometer 10. Since the optical path difference of the sensor has a fixed relation delta 2n (T) L (T) with the refractive index of the sapphire wafer and the thermal expansion length of the wafer, the sensing real-time temperature can be obtained by reverse extrapolation.
Fig. 5 shows a test result in a laboratory environment, and fig. 5(a) shows the fluctuation amount of the optical path difference at each temperature, which is obtained by acquiring 100 frames of data at each temperature and making a standard deviation, and is also referred to as the temperature measurement resolution of the temperature sensor, in the case where the high-fringe visibility sensor and the conventional sapphire optical fiber fabry-perot sensor are stepped at 100 ℃. Temperature sensors with high fringe visibility can be seen to have higher thermometry resolution due to higher signal quality. Fig. 5(b) shows the difference between the temperature measurement results of the high-fringe visibility sensor and the conventional sapphire fiber fabry-perot sensor at various temperatures and the set temperature in the high-temperature muffle furnace, which is also the temperature measurement error of the sensor. The temperature measurement precision of the high-fringe visibility sensor is +/-1 ℃, and the high-fringe visibility sensor has higher measurement precision compared with the traditional sensor.
Example 2:
the high-temperature muffle furnace is set to be 1000 ℃, the high-stripe visibility sensor and the traditional sapphire optical fiber Fabry-Perot sensor are sequentially placed at the same position in the high-temperature furnace cavity, 1-hour data are continuously collected after the ambient temperature is stable, the temperature measurement stability of the sensor is analyzed, and the experimental result is shown in fig. 6. It can be seen from the figure that the high fringe visibility sapphire fiber Fabry-Perot sensor has better temperature stability than the traditional single fiber sensor.
Claims (3)
1. A sapphire optical fiber Fabry-Perot high-temperature sensor with high stripe contrast is characterized by comprising a sapphire wafer (1), a sapphire ferrule (2) and sapphire-quartz optical fibers forming optical signal transmission waveguides in a high-temperature region and a normal-temperature region; the sapphire wafer (1) and the sapphire ferrule (2) are tightly attached to each other in circular section and are fixed by high-temperature ceramic cement (3); the sapphire-quartz optical fiber is formed by welding a sapphire optical fiber (4) and a flattened quartz optical fiber (5) through an optical fiber welding point (6) between end faces, and an input waveguide 21 and an output waveguide 22 are formed; the sapphire-quartz optical fiber is inserted into the middle hole of the sapphire ferrule (2) from one end of the sapphire optical fiber (4), and the optimal position of a sensing signal between the sapphire optical fiber (4) and the sapphire wafer (1) is fixed by using high-temperature ceramic glue (3); the sapphire-quartz optical fiber is respectively connected with an LED light source (9) and a spectrometer (10) from one end of a quartz optical fiber (5) through an optical fiber jumper (7), so that the shunt transmission of an input waveguide (21) and an output waveguide (22) is realized, and an interference signal is finally transmitted to the spectrometer; the two reflecting surfaces of the sapphire wafer (1) form a Fabry-Perot interference cavity, and the diffused light irradiates a first reflecting surface (16) of the sapphire wafer (1) to be reflected for the first time to form a first beam of reflected light (11); the rest part of light is transmitted to a second reflection surface (17) of the sapphire wafer (1) to be reflected for the second time, a second beam of reflected light (12) carrying optical path difference information is formed, an input waveguide (21) projects an original light signal emitted by an LED light source (9) onto the sapphire wafer (1), and an output waveguide (22) receives interference signals reflected from the two reflection surfaces of the sapphire wafer (1), so that the input signal light and the output signal light are separated by a double optical path.
2. The temperature measurement method implemented by the high fringe contrast sapphire fiber Fabry-Perot high temperature sensor according to claim 1, wherein the method comprises the following steps:
connecting a high-temperature sensor (8) in a working state with an LED light source (9) and a spectrometer (10) through an optical fiber jumper (7); light emitted by an LED light source (9) enters a high-temperature sensor (8) through an optical fiber jumper (7), is emitted from a sapphire optical fiber end face (15) through a heterogeneous optical fiber fusion point (6), and is radiated to a first reflecting surface (16) of a sapphire wafer (1) to be reflected for the first time to form a first beam of reflected light (11); the rest part of the light is transmitted to a second reflection surface (17) of the wafer to be reflected for the second time, and a second beam of reflection light (12) carrying optical path difference information is formed; the first beam of reflected light (11) and the first beam of reflected light (12) generated on the two surfaces of the Fabry-Perot interference cavity are coupled into the sapphire optical fiber (4) to be output, so that a Fabry-Perot double-optical-fiber interference signal (18) is formed, namely the optical path difference between the two beams of reflected light of the first beam of reflected light (11) and the second beam of reflected light (12) is changed along with the first beam of reflected light and the second beam of reflected light, so that the interference signal is changed; the interference signal (18) is transmitted back to the spectrometer (10) through the sapphire optical fiber (4), the quartz optical fiber (5) and the optical fiber jumper (7);
the interference spectrum signal collected from the spectrometer is represented as:
wherein k is 2 pi/λ; i isB(k) Representing the amount of DC background, S, in the interference spectrum signal1(k),S2(k) Representing two reflected lights received by the optical fiber, delta representing the optical path difference between the two coherent lights,
representing the initial optical path difference, L, n representing the thickness and refractive index of the sapphire wafer;
when the temperature of the environment changes, the thickness and the material refractive index of the sapphire wafer change:
the formula of the change of the refractive index of the sapphire wafer with the temperature is expressed as follows:
n(T)850nm＝a0+a1T+a2T2
wherein T is temperature in centigrade, n (T)850nmThe refractive index of the sapphire wafer material is below 850 nm;
the thermal expansion function of the sapphire material along the C-axis is expressed as:
L(T)＝[b0+b1T+b2T2+b3T3]×L0
wherein T represents a Kelvin temperature, L (T) represents a temperature T and an initial length L0An initial length under conditions;
as can be seen from the above, the optical path difference Δ is 2n (T) l (T) and is expressed by a fifth-order polynomial relationship of the temperature T, and the fabry-perot optical path difference is obtained by demodulating the interference signal by the spectroscopic method, and the temperature at which the sapphire wafer is located is further reversely returned.
3. The temperature measuring method according to claim 2, wherein in the step of obtaining the information of the fabry-perot optical path difference by spectroscopically demodulating the interference signal, the demodulation accuracy depends on the acquisition resolution of the interference spectrum and the accurate finding of the fringe peak position: spectral acquisition resolution is determined from spectraThe resolution of the instrument determines that the peak position is accurately found and closely related to the visibility of the interference spectral fringes, so in practical measurement, the visibility of the interference spectral fringes is further expressed as:
wherein FVIndicating the visibility of the interference fringes in the background light signal.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103913254A (en) * | 2014-04-28 | 2014-07-09 | 武汉理工大学 | Sapphire optical fiber high-temperature sensor and manufacturing method thereof |
| CN105806414A (en) * | 2016-04-26 | 2016-07-27 | 浙江大学 | Optical fiber temperature and humidity sensor, temperature and humidity sensing system and temperature and humidity regulating method |
| CN106066215A (en) * | 2016-07-29 | 2016-11-02 | 武汉理工大学 | A kind of sapphire pyrostat |
| CN206618510U (en) * | 2017-04-11 | 2017-11-07 | 湖北师范大学 | A kind of transmission-type fibre optic temperature sensor of multi-core fiber dislocation welding |
| CN108332876A (en) * | 2018-01-30 | 2018-07-27 | 华中科技大学 | A kind of fibre optic temperature sensor |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB0408073D0 (en) * | 2004-04-08 | 2004-05-12 | Council Cent Lab Res Councils | Optical sensor |
| JP5591565B2 (en) * | 2010-03-12 | 2014-09-17 | 東京エレクトロン株式会社 | Temperature measuring probe, temperature measuring system, and temperature measuring method using the same |
| WO2014176500A1 (en) * | 2013-04-25 | 2014-10-30 | Sentek Instrument LLC | Sapphire sensor for measuring pressure and temperature |
-
2018
- 2018-12-05 CN CN201811479759.7A patent/CN109580035B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103913254A (en) * | 2014-04-28 | 2014-07-09 | 武汉理工大学 | Sapphire optical fiber high-temperature sensor and manufacturing method thereof |
| CN105806414A (en) * | 2016-04-26 | 2016-07-27 | 浙江大学 | Optical fiber temperature and humidity sensor, temperature and humidity sensing system and temperature and humidity regulating method |
| CN106066215A (en) * | 2016-07-29 | 2016-11-02 | 武汉理工大学 | A kind of sapphire pyrostat |
| CN206618510U (en) * | 2017-04-11 | 2017-11-07 | 湖北师范大学 | A kind of transmission-type fibre optic temperature sensor of multi-core fiber dislocation welding |
| CN108332876A (en) * | 2018-01-30 | 2018-07-27 | 华中科技大学 | A kind of fibre optic temperature sensor |
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