CN100478660C - High sensitivity optical fiber temperature sensor - Google Patents
High sensitivity optical fiber temperature sensor Download PDFInfo
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- CN100478660C CN100478660C CNB2007100597900A CN200710059790A CN100478660C CN 100478660 C CN100478660 C CN 100478660C CN B2007100597900 A CNB2007100597900 A CN B2007100597900A CN 200710059790 A CN200710059790 A CN 200710059790A CN 100478660 C CN100478660 C CN 100478660C
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- optical fiber
- wavelength
- temperature sensor
- multimode optical
- box shell
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Abstract
The utility model discloses a high-sensitivity optical fiber temperature transmitter, which belongs to the technical field of fiber optic sensing, and comprises an aluminum or aluminum alloy pipe or box shell; wherein, a segment of multimode optical fiber is arranged hermetically in the pipe or box shell; the core of the multimode optical fiber with a diameter of 50 to 250 Mu m is made of quartz; the covering of the multimode optical fiber is formed by polyimide with a thermo-optical coefficient of minus one ten-thousandth to minus five ten-thousandth per centidegree; one end of the multimode optical fiber is connected with single model input optical fibers, and the other end is connected with single mode output optical fibers; the single mode input and output optical fibers are bonded with the ports of the pipe or box shell with epoxy resin adhesives. The utility model has the advantages of simple structure, easy manufacture, and convenient use. In addition, the utility model reaches a sensitivity of minus three point nine fifteen per centidegree, which is several times or decades of times than that of the prior wavelength encoding type optical fiber temperature sensor, meanwhile has the same wavelength encoding and division multiplex as the fiber bragg grating (FBG).
Description
Technical field
The present invention relates to a kind of fibre optic temperature sensor, particularly a kind of high sensitivity optical fiber temperature sensor with Wavelength-encoding characteristic belongs to sensory field of optic fibre.
Background technology
Fibre Optical Sensor has the incomparable advantage of many electric transducers, as the influence that not changed by electromagnetic field and other external environment, highly sensitive, volume is little, good insulating, can realize distribution measuring etc., therefore more and more come into one's own.Many physical quantitys such as temperature, strain, displacement, humidity, pressure, sound, vibration etc. can use Fibre Optical Sensor to carry out high-precision measurement.Fibre Optical Sensor has been widely used in fields such as building, oil, chemical industry, traffic, the energy, metallurgy, medicine, military project, food, nuclear industry.
According to its principle of work, Fibre Optical Sensor can be divided into intensity modulation type and Wavelength-encoding type.As its name suggests, the Fibre Optical Sensor with the work of Wavelength-encoding mode is that promptly tested measured change will be converted into the variation of light wavelength with the sign of light wavelength as tested measurement.Its great advantage is exactly that the information of tested measurement can not change with the change of light intensity, i.e. the information of tested measurement can be because of the size of the loss of the length of Transmission Fibers and optical fiber link and changed, and this is very important for telemeasurement.In addition, the Fibre Optical Sensor with Wavelength-encoding function can adopt the mode of wavelength multiplexing that a plurality of sensor strings are connected in the same optical fiber link, thereby realizes multiple spot or distributed measurement.The shortcoming of Wavelength-encoding type Fibre Optical Sensor is that the equipment that needs the Wavelength demodulation function extracts tested measurement from light wavelength, that is to say, needs to measure light wavelength.Compare with ionization meter, it is complicated that wavelength measurement is wanted, and generally need just can finish by spectral analysis.
At present, existing several different methods and technology can realize the optical fiber sensing of Wavelength-encoding type, and wherein use more extensively has employing Fiber Bragg Grating FBG (being called for short FBG) technology, long period fiber grating (being called for short LPG) technology, fiber F-P technology and optical fiber multiple-mode interfence (MMI) technology etc.Be about 11pm/ ℃ by the FBG of standard traffic optical fiber fabrication and the wavelength-temperature control of MMI temperature sensor.LPG is during as temperature sensor, the exponent number of the cladding mode that the size of its wavelength-temperature control and symbol all depend on LPG and utilized.Wavelength-the temperature control that has realized at present is at-140pm/ ℃ to-340pm/ ℃.Wavelength-the temperature control of fibre optic temperature sensor is an important techniques index, high wavelength-temperature control not only helps improving the precision and the resolution of measurement, requirement can also be reduced, thereby the manufacturing cost of whole temperature-sensing system can be reduced Wavelength demodulation system.
Summary of the invention
Purpose of the present invention just provides a kind of high sensitivity optical fiber temperature sensor, this fibre optic temperature sensor is simple in structure, sensitivity reaches-3.915nm/ ℃, be several times to tens times of optical fiber sensing of existing Wavelength-encoding type, have characteristics such as Wavelength-encoding identical and wavelength-division multiplex simultaneously with FBG.
The present invention is realized by following technical proposals, a kind of high sensitivity optical fiber temperature sensor, it is characterized in that, this fibre optic temperature sensor comprises the shell or the box shell 106 of aluminum or aluminum alloy, one section multimode optical fiber 102 of encapsulation in 106, the fibre core of this multimode optical fiber is a quartz material, and its diameter is 50-250 μ m, and its covering is that to have thermo-optical coeffecient be-1.0 * 10
-4/ ℃ to-5.0 * 10
-4/ ℃ polyimide material; One end of multimode optical fiber connects single mode input optical fibre 101, and the other end connects single mode output optical fibre 105, is epoxy resin adhesive 104 between the port of single mode input and output optical fiber and shell or box shell.
The present invention realizes that the principle of high sensitivity thermometric is as follows:
The optical fiber multiple-mode interfence sensor of single-mode fiber-multimode optical fiber-single-mode fiber of forming by silica fibre (being called for short SMS) structure, its wavelength-temperature control can be expressed as:
Wherein, α
1And ξ
1Be respectively the thermal expansivity and the thermo-optical coeffecient of multimode optical fiber fibre core.Since silica fibre material coefficient of thermal expansion coefficient and thermo-optical coeffecient be on the occasion of, therefore the interference of SMS optical fiber multiple-mode interfence instrument wavelength very big or minimum correspondence will move to the long wave direction when temperature raises.On the other hand, apply pulling force as the two ends at SMS optical fiber multiple-mode interfence instrument, optical fiber will produce strain stress, the wavelength that causes thus move into:
In the following formula, v is the Poisson's Ratio of multimode optical fiber core material; p
eEquivalent elasto-optical coefficient for the multimode optical fiber core material.By following formula as can be known, applying pulling force at the two ends at SMS optical fiber multiple-mode interfence instrument will make the interference wavelength very big or minimum correspondence of SMS optical fiber multiple-mode interfence instrument move to the shortwave direction.
If consider the hot light characteristic of multimode optical fiber clad material, then the interference wavelength change very big or minimum correspondence of the SMS optical fiber multiple-mode interfence instrument that is caused by temperature variation can be expressed as:
Wherein, χ is a constant; ξ
2Thermo-optical coeffecient for the multimode optical fiber clad material.The variation of actual wavelength is the comprehensive effect of above-mentioned various factors
Δλ＝Δλ
1+Δλ
2+Δλ
3＝λ[(α
1+ξ
1)ΔT-(1+2v+p
e)ε+χξ
2ΔT]。
When selecting expansion coefficient for use is α
2Encapsulation (shell or box shell) material, and the two ends of SMS optical fiber multiple-mode interfence instrument are fixed on this encapsulating material.When temperature variation, be by multimode optical fiber core material and encapsulation (shell or the box shell) strain that difference caused of material on expansion coefficient:
ε＝(α
2-α
1)ΔT
Expression formula with this formula substitution Δ λ obtains:
Δλ＝λ[(α
1+ξ
1+χξ
2)-(1+2v+p
e)(α
2-α
1)]ΔT。
This shows, when the clad material of multimode optical fiber is the polyimide polymer material, because its thermo-optical coeffecient ξ
2Thermo-optical coeffecient ξ much larger than quartz material
1, and be negative value, thus be that the SMS optical fiber multiple-mode interfence instrument of covering has very high temperature control by polyimide polymer, and on symbol, be negative value.Promptly when temperature raise, the interference of SMS optical fiber multiple-mode interfence instrument wavelength very big or minimum correspondence moved to the shortwave direction.Simultaneously, adopt encapsulating material that sensor temperature sensitivity is further improved with high thermal expansion coefficient.
The invention has the advantages that, simple in structure, easy to manufacture.The sensitivity of this fibre optic temperature sensor reaches-3.915nm/ ℃, and be several times to tens times of optical fiber sensing of existing Wavelength-encoding type, have characteristics such as Wavelength-encoding identical and wavelength-division multiplex simultaneously with FBG, easy to use.
Description of drawings
Fig. 1 is a high sensitivity optical fiber temperature sensor structural representation of the present invention.
Among the figure: 101 are the input single-mode fiber; 102 is the fibre core of multimode optical fiber; 103 is the polyimide covering of multimode optical fiber; 104 is bonding agent; 105 are the output single-mode fiber; 106 is the shell of aluminum or aluminum alloy.
Fig. 2 is the optical-fiber temperature measuring Experimental equipment.
Among the figure: 201 is wideband light source; 202 are provided with the temperature cycles case of high sensitivity optical fiber temperature sensor of the present invention in being; 204 is spectrometer.
Fig. 3 is the transmitted light spectrogram of the fibre optic temperature sensor of record.
Fig. 4 is the relation of observed temperature and wavelength variations.
Embodiment
Below in conjunction with accompanying drawing the specific embodiment of the present invention is elaborated.As shown in Figure 1, input single-mode fiber 101 and output single-mode fiber 105 adopt standard single mode telecommunication optical fiber (G652), and its core diameter is 8.2 μ m, and cladding diameter is 125 μ m, numerical aperture 0.14.At first its protective finish is removed, used the optical fiber cutting knife that its end face is cut into and its axis normal then.The multimode optical fiber fibre core is pure quartz, and its diameter is 125 μ m, and length is 55mm.The covering 103 of multimode optical fiber is a polyimide material, and its diameter is 250 μ m, and length is 45mm.Use the optical fiber cutting knife that its end face is cut into and its axis normal.Afterwards, the single-mode fiber after the end face processing is put into optical fiber splicer with multimode optical fiber three sections fused fiber splices are in the same place, constitute SMS optical fiber multiple-mode interfence instrument.For constituting fibre optic temperature sensor, use epoxy resin that SMS optical fiber multiple-mode interfence instrument is fixed in the metal tube that is processed into by aluminium alloy at its two ends.
To quartz material, known its parameter alpha
1=5 * 10
-7/ ℃, ξ
1=6.9 * 10
-6/ ℃, p
e=0.22, v=0.16.For the polyimide clad material, its thermo-optical coeffecient ξ
2-1.0 * 10
-4/ ℃ magnitude.The expansion coefficient α of the aluminium alloy that uses
2=22 * 10
-6/ ℃.
Fig. 2 is the optical-fiber temperature measuring Experimental equipment.201 is wideband light source, and its output spectrum scope is 1520-1565nm, and output power is 5mW; 202 is the temperature cycles case, can be provided with and the change temperature at-40 ℃ to 150 ℃, and its temperature resolution and degree of stability are 0.1 ℃; Temperature sensor places in the temperature cycles case 202; 203 is fibre optic spectral analyzer, as spectrum record and Wavelength demodulation equipment.
Fig. 3 is the spectrogram of experimental record when temperature is 32.5 ℃, is illustrated among the figure in the used wideband light source effective spectral range of experiment, and it is minimum a main interference to occur.
Fig. 4 is the relation of observed temperature and wavelength variations.Minimum with the most tangible interference in the experiment is sign, measures this and interfere minimum pairing wavelength under different temperatures.Can see by experimental result, the variable quantity of resonance wavelength and the temperature relation of being in line, its slope is a negative value.In the selected temperature range (25-40 ℃), wavelength-temperature control be-3.195nm/ ℃, and this is worth the wavelength-temperature control much larger than other existing Wavelength-encoding type fibre optic temperature sensor.
Those skilled in the art are clear, and thought of the present invention can adopt the alternate manner beyond the above-named embodiment to realize.
Claims (1)
1. high sensitivity optical fiber temperature sensor, it is characterized in that, this fibre optic temperature sensor comprises the shell or the box shell (106) of aluminum or aluminum alloy, encapsulation one section multimode optical fiber (102) in shell or box shell (106), the fibre core of this multimode optical fiber is a quartz material, its diameter is 50-250 μ m, and its covering is that to have thermo-optical coeffecient be-1.0 * 10
-4/ ℃ to-5.0 * 10
-4/ ℃ polyimide material; One end of multimode optical fiber connects single mode input optical fibre (101), and the other end connects single mode output optical fibre (105), is epoxy resin adhesive (104) between the port of single mode input and output optical fiber and shell or box shell.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2007100597900A CN100478660C (en) | 2007-09-27 | 2007-09-27 | High sensitivity optical fiber temperature sensor |
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|---|---|---|---|
| CNB2007100597900A CN100478660C (en) | 2007-09-27 | 2007-09-27 | High sensitivity optical fiber temperature sensor |
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| CN100478660C true CN100478660C (en) | 2009-04-15 |
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Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2013534433A (en) * | 2010-05-13 | 2013-09-05 | コーニンクレッカ フィリップス エヌ ヴェ | Optical fiber shape reconstruction |
| CN102288326B (en) * | 2011-07-07 | 2013-03-27 | 天津大学 | Method and sensor for measuring temperature of photonic crystal fiber (PCF) filled with mixed solution |
| CN102410886B (en) * | 2011-08-30 | 2014-02-05 | 深圳大学 | Fiber temperature sensor and measuring system thereof and signal processing method of system |
| CN103134608A (en) * | 2011-11-23 | 2013-06-05 | 成都酷玩网络科技有限公司 | High-stability double-barreled fiber bragg grating temperature sensor |
| CN103076111B (en) * | 2013-01-06 | 2015-07-29 | 北京交通大学 | Based on single mode-multi-mode-single mode modal interference temperature measuring equipment |
| CN103487163A (en) * | 2013-09-10 | 2014-01-01 | 中国石油集团渤海钻探工程有限公司 | Manufacturing method of high-sensitivity optical fiber temperature and lateral pressure sensor |
| CN103940530B (en) * | 2014-03-21 | 2016-05-04 | 哈尔滨工程大学 | A kind of temperature sensor based on hollow annular waveguide fiber |
| CN103926020B (en) * | 2014-05-06 | 2016-08-31 | 天津理工大学 | A kind of based on S type structured optical fiber and the temperature sensor of air chamber |
| CN105021308B (en) * | 2015-07-15 | 2018-01-19 | 哈尔滨工程大学 | A kind of aluminium modifies enhanced fiber grating temperature sensor manufacture method |
| CN105783781A (en) * | 2016-05-04 | 2016-07-20 | 中国计量大学 | Curvature sensor based on cladding mode interference with fiber Bragg grating |
| CN108279079B (en) * | 2018-01-08 | 2020-11-24 | 东北大学 | Point type temperature sensing device based on radial large dislocation structure coating polydimethylsiloxane of coreless optical fiber |
| RU187529U1 (en) * | 2018-10-24 | 2019-03-12 | Федеральное Государственное Унитарное Предприятие "Всероссийский Научно-Исследовательский Институт Автоматики Им.Н.Л.Духова" (Фгуп "Внииа") | Spectral Temperature Transmitter |
| CN110687076A (en) * | 2019-10-28 | 2020-01-14 | 中国科学院西安光学精密机械研究所 | Humidity sensor based on polymer optical fiber mode interferometer |
| CN113125041B (en) * | 2021-04-15 | 2022-01-11 | 武汉理工大学 | Dual-sensitivity high-sensitivity FBG temperature sensor and manufacturing method thereof |
| CN113281303A (en) * | 2021-06-29 | 2021-08-20 | 哈尔滨理工大学 | Vernier sensitization semi-filled polyimide optical fiber FPI humidity sensor |
| CN113865743B (en) * | 2021-10-13 | 2023-01-31 | 广东感芯激光科技有限公司 | Optical fiber distributed battery multipoint temperature measurement system and application |
| CN114755202B (en) * | 2022-06-15 | 2022-09-02 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Optical fiber distributed humidity sensor based on polyimide and positioning detection method |
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