CN103134775A - Optical fiber liquid refractive index and temperature sensor - Google Patents
Optical fiber liquid refractive index and temperature sensor Download PDFInfo
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- CN103134775A CN103134775A CN2011103989939A CN201110398993A CN103134775A CN 103134775 A CN103134775 A CN 103134775A CN 2011103989939 A CN2011103989939 A CN 2011103989939A CN 201110398993 A CN201110398993 A CN 201110398993A CN 103134775 A CN103134775 A CN 103134775A
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Abstract
An optical fiber liquid refractive index and temperature sensor is characterized by comprising a light source (1), an optical fiber (2), an annular device (3), a long cycle grating (4), a spectrum analyzer (5), a reflector (6), an optical fiber (7), and a liquid pond (8). The light source (1) is connected with the annular device (3) through the optical fiber (2). The annular device (3) is respectively connected with the long cycle grating (4) and the spectrum analyzer (5) through the optical fiber (2). The long cycle grating (4) is connected with the reflector (6) through the optical fiber (7). Optical waves sent by the light source (1) pass through the long cycle grating (4) in transmission processes, and then are divided into two paths which are respectively transmitted in a fiber core and a cladding, return along the original paths after going through the reflector (6), form interference in the annular device (3), and then are transmitted to the spectrum analyzer (5) through the optical fiber (2) to be displayed and output. After the optical waves are divided into the two paths, the optical fiber liquid refractive index in the cladding is influenced by the outside environment so as to form interference patterns, and therefore the outside refractive index can be measured. The optical fiber liquid refractive index and temperature sensor is high in sensitivity and simple in structure, and has good application prospects.
Description
Technical field
The invention provides a kind of fiber liquid refractive index and temperature sensor, belong to technical field of optical fiber sensing.
Background technology
Based on the characteristics such as simple in structure, that sensitivity is high, Fibre Optical Sensor has been obtained in Practical Project widely and has been used.For measuring refractive indexes of liquid, traditional method is with the quartzy covering corrosion of optical fiber, changes with the refractive index sensitive material and substitutes covering, makes optical fiber sensor head, and its shortcoming is that etching process is complicated, is difficult to control.Perhaps with two optical fiber weldings together as optical fiber sensor head, so also to destroy optical fiber, the sensing weak effect, sensing accuracy is poor; And adopt long-period gratings to consist of the Michelson structure as the survey instrument of liquid refractivity, have higher coupling efficiency and the higher characteristics such as sensitivity.
Summary of the invention
The object of the present invention is to provide a kind of fiber liquid refractive index and temperature sensor.This device can change the external environments such as the refractive index of testing liquid, ambient temperature the phase place that is converted into interference pattern and change.Have the advantages such as simple in structure and sensitivity height.
The present invention is achieved through the following technical solutions:
A kind of fiber liquid refractive index and temperature sensor is characterized in that: be comprised of light source (1), optical fiber (2), circulator (3), long-period gratings (4), spectroanalysis instrument (5), catoptron (6), optical fiber (7) and liquid cell (8); Light source (1) is connected with circulator (3) through optical fiber (2), circulator (3) passes through optical fiber (2) and is connected with long-period gratings (4), spectroanalysis instrument (5) respectively, be connected by optical fiber (2) between long-period gratings (4) and catoptron (6), optical fiber (7) immerses in testing liquid pond (8).
Described a kind of fiber liquid refractive index and temperature sensor is characterized in that: centered by light source (1), wavelength is that 1540nm, bandwidth are the wideband light source of 100-200nm.
Described a kind of fiber liquid refractive index and temperature sensor is characterized in that: the length of long-period gratings is 10-20mm.
Described a kind of fiber liquid refractive index and temperature sensor is characterized in that: single-mode fiber (7) is as sensing probe, and its length is 20-50mm.
Described a kind of fiber liquid refractive index and temperature sensor is characterized in that: the end face of optical fiber (7) is gold-plated or silver-colored, as catoptron (6).
principle of work of the present invention is: light wave propagates into a port of circulator (3) from light source (1), again from another port output of circulator (3), propagate into long-period gratings (4) along optical fiber (2) with suitable centre wavelength and coupling value, effect due to long-period gratings (4), the part light wave is propagated along the adterminal catoptron of fibre core (6) of optical fiber (2), the catoptron (6) of part light wave along the covering of optical fiber (2) to optical fiber connector, two-way light returns through catoptron (6) Hou Yuanlu, after again passing through long-period gratings (4), part fibre core light wave is coupled into the covering mode by fibre core, disappear after light wave propagation one segment distance in covering, same, part covering light wave is coupled into the fibre core mode, remaining covering light wave continues to propagate along covering simultaneously, disappear after light wave propagation one segment distance in covering, the light wave that two-way is propagated to circulator (3) in the fibre core of optical fiber (7) occurs mutually to interfere, the 3rd port output at circulator, obtain interference pattern in spectroanalysis instrument (5).When optical fiber (7) when external environment changes, external interference may be influential to the light wave propagation light path, perhaps only light path is wherein worked, finally can affect the optical path difference of the two-way light wave of the middle covering of optical fiber (7) and fibre core, cause simultaneously the respective change of interference pattern, can measure extraneous refractive index with this.
The invention has the beneficial effects as follows: this device can change the external environments such as the refractive index of testing liquid, ambient temperature the phase place that is converted into interference pattern and change, by measuring phase place under reference state and variation under the state of external environment impact arranged, extrapolate corresponding refractive index and temperature, if testing liquid is potpourri, can also further obtain mixture concentration by refractive index; This refractive index has the advantages such as simple in structure and sensitivity height simultaneously.
Description of drawings
Fig. 1 is a kind of fiber liquid refractive index of the present invention and temperature sensor schematic diagram;
Fig. 2 is that detecting head of the present invention is in air and complete interference pattern when water-immersed;
Fig. 3 of the present inventionly is immersed in the water the different degree of depth and changes lab diagram with corresponding phase place;
Fig. 4 is the refractive index of potpourri of the present invention and the lab diagram that phase place changes;
Fig. 5 is the phase place variation of the optical fiber of germanium boron of the present invention and the optical fiber of mixing hydrogen and the lab diagram of sensor temperature;
Fig. 6 is the function relation figure of phase place variation of the present invention and sensor temperature;
Fig. 7 is the transmittance variation with temperature graph of a relation of different temperatures lower sensor of the present invention.
Embodiment
The invention will be further described below in conjunction with accompanying drawing and embodiment:
Referring to accompanying drawing 1 and Fig. 2, a kind of fiber liquid refractive index and temperature sensor is characterized in that: be comprised of light source (1), optical fiber (2), circulator (3), long-period gratings (4), spectroanalysis instrument (5), catoptron (6), optical fiber (7) and liquid cell (8); Light source (1) is connected with circulator (3) through optical fiber (2), circulator (3) passes through optical fiber (2) and is connected with long-period gratings (4), spectroanalysis instrument (5) respectively, be connected by optical fiber (2) between long-period gratings (4) and catoptron (6), optical fiber (7) immerses in testing liquid pond (8), the end face of optical fiber (7) is silver-plated, as catoptron (6).
As shown in Figure 3, centered by the light source of selecting in this example (1), wavelength is that 1540nm, bandwidth are the wideband light source of 120nm, long-period gratings length is 12.5mm, the length of optical fiber (7) is 45mm, the refringence 0.03 of fibre core and covering can obtain being immersed in the water the interference pattern of (the 45mm degree of depth) in air and fully; As shown in Figure 4, change when detecting head is immersed in the water with different depth the phase place that obtains, phase place can obtain a slope about immersed depth when changing be 2.67 linear function; When changing water into potpourri (G ﹠ W), the refractive index that obtains by experiment potpourri (G ﹠ W) is a function of this mixture concentration, the concentration range of glycerine is 0 to 80%, when detecting head immerses in potpourri (the 45mm degree of depth) fully, the phase place that obtains changes the graph of a relation with refractive index, and as shown in the figure 5; Simultaneously, when the factor of describing the external environment variation is temperature, sensor is placed in a constant temperature oven that temperature is controlled, select the set-point in the scope of 15 degrees centigrade and 95 degrees centigrade, use respectively the optical fiber of mixing germanium boron and mix the optical fiber of hydrogen as sensing head, can obtain equally the function of phase place variation and sensor temperature, the sensitivity of corresponding phase transition temperature is-2.5 °/℃ and 12.8 °/℃, as shown in Figure 6; When the covering of optical fiber (7) is in respectively 16.6 degrees centigrade and 82 degrees centigrade, wavelength coverage is 1480-1600nm, obtain two curves and derive from interference pattern under different temperatures, as shown in Figure 7, wavelength coverage corresponding to minimum transmittance is between 1537-1514nm, and variation with temperature is for changing.
Claims (5)
1. a fiber liquid refractive index and temperature sensor, is characterized in that: be comprised of light source (1), optical fiber (2), circulator (3), long-period gratings (4), spectroanalysis instrument (5), catoptron (6), optical fiber (7) and liquid cell (8); Light source (1) is connected with circulator (3) through optical fiber (2), circulator (3) passes through optical fiber (2) and is connected with long-period gratings (4), spectroanalysis instrument (5) respectively, be connected by optical fiber (2) between long-period gratings (4) and catoptron (6), optical fiber (7) immerses in testing liquid pond (8).
2. a kind of fiber liquid refractive index according to claim 1 and temperature sensor, it is characterized in that: centered by light source (1), wavelength is that 1540nm, bandwidth are the wideband light source of 100-200nm.
3. a kind of fiber liquid refractive index according to claim 1 and temperature sensor, it is characterized in that: the length of long-period gratings is 10-20mm.
4. a kind of fiber liquid refractive index according to claim 1 and temperature sensor, it is characterized in that: single-mode fiber (7) is as sensing probe, and its length is 20-50mm.
5. a kind of fiber liquid refractive index according to claim 1 and temperature sensor, it is characterized in that: the end face of optical fiber (7) is gold-plated or silver-colored, as catoptron (6).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103989939A CN103134775A (en) | 2011-11-30 | 2011-11-30 | Optical fiber liquid refractive index and temperature sensor |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2011103989939A CN103134775A (en) | 2011-11-30 | 2011-11-30 | Optical fiber liquid refractive index and temperature sensor |
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| CN103134775A true CN103134775A (en) | 2013-06-05 |
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| CN2011103989939A Pending CN103134775A (en) | 2011-11-30 | 2011-11-30 | Optical fiber liquid refractive index and temperature sensor |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103645145A (en) * | 2013-12-17 | 2014-03-19 | 中国计量学院 | Optical fiber hydrogen sensor |
| CN103926019A (en) * | 2014-04-24 | 2014-07-16 | 中国科学技术大学 | Optical fiber temperature sensor and manufacturing method thereof |
| CN105866071A (en) * | 2016-06-02 | 2016-08-17 | 吉林大学 | Device for measuring refractive index through optical fiber interferometry |
| CN108181271A (en) * | 2017-12-22 | 2018-06-19 | 北京信息科技大学 | For fibre-optical microstructure sensor of temperature and liquid refractivity sensing measurement and preparation method thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN2807226Y (en) * | 2004-11-17 | 2006-08-16 | 中国科学院上海光学精密机械研究所 | Long period optical fiber grating temperature sensor |
| CN101929955A (en) * | 2010-05-31 | 2010-12-29 | 华南师范大学 | Optical fiber Bragg grating refractive index sensor |
| CN102141513A (en) * | 2010-12-30 | 2011-08-03 | 华中科技大学 | Refractive index sensor of micro-nano optical fiber |
| CN102226725A (en) * | 2011-03-29 | 2011-10-26 | 哈尔滨工程大学 | Inner-wall waveguide long-time cycle fiber grating sensor |
-
2011
- 2011-11-30 CN CN2011103989939A patent/CN103134775A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2807226Y (en) * | 2004-11-17 | 2006-08-16 | 中国科学院上海光学精密机械研究所 | Long period optical fiber grating temperature sensor |
| CN101929955A (en) * | 2010-05-31 | 2010-12-29 | 华南师范大学 | Optical fiber Bragg grating refractive index sensor |
| CN102141513A (en) * | 2010-12-30 | 2011-08-03 | 华中科技大学 | Refractive index sensor of micro-nano optical fiber |
| CN102226725A (en) * | 2011-03-29 | 2011-10-26 | 哈尔滨工程大学 | Inner-wall waveguide long-time cycle fiber grating sensor |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103645145A (en) * | 2013-12-17 | 2014-03-19 | 中国计量学院 | Optical fiber hydrogen sensor |
| CN103926019A (en) * | 2014-04-24 | 2014-07-16 | 中国科学技术大学 | Optical fiber temperature sensor and manufacturing method thereof |
| CN105866071A (en) * | 2016-06-02 | 2016-08-17 | 吉林大学 | Device for measuring refractive index through optical fiber interferometry |
| CN105866071B (en) * | 2016-06-02 | 2019-04-26 | 吉林大学 | A kind of fiber optic interferometric method surveys the device of refractive index |
| CN108181271A (en) * | 2017-12-22 | 2018-06-19 | 北京信息科技大学 | For fibre-optical microstructure sensor of temperature and liquid refractivity sensing measurement and preparation method thereof |
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Application publication date: 20130605 |