CN101957227B - Photonic crystal fiber optic liquid level sensor and sensing system formed by same - Google Patents
Photonic crystal fiber optic liquid level sensor and sensing system formed by same Download PDFInfo
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Abstract
The invention belongs to liquid level measurement, in particular relates to a photonic crystal fiber optic liquid level sensor and a system formed by same. The photonic crystal fiber optic liquid level sensor is characterized by comprising a single mode fiber SMF-28 and a photonic crystal fiber SC-4.0, wherein the single mode fiber SMF-28 is fused with the beginning end of the photonic crystal fiber SC-4.0; a beginning end cladding air hole of the photonic crystal fiber is closed at a fusing point to form a beginning end complete collapsing area; the length of the beginning end complete collapsing area is equal to 65 mu m; a fusing machine is used for charging the tail end of the photonic crystal fiber to form a tail end collapsing area; and a reflecting film is plated on the tail end of the photonic crystal fiber. The whole sensor is completely made of optical fibers and has convenient manufacture and no need of optical fiber corrosion. The sensing system is free from the influence of stray light and temperature and has the advantages of less signal noise, high system sensitivity and high reliability.
Description
Technical Field
The invention belongs to liquid level measurement, and particularly relates to a photonic crystal fiber liquid level sensor and a system formed by the same.
Background
In industrial production, liquid level measurement is often required, and the traditional detection methods include an operating method, a float method, an electrical method and the like, but the methods have inherent defects in the aspects of automation, precision, safety and the like. The optical fiber sensor has the characteristics of intrinsic safety and high precision, and the defects of the traditional method are overcome. Many optical fiber liquid level sensors are mainly of the light intensity modulation type, and include the leakage mode [1], the total internal reflection based [2] to [5], and the liquid level reflection type. However, these optical fiber liquid level sensors also have obvious disadvantages, some are severely limited by physicochemical properties of the measured liquid, some have small measuring range, some have low precision, some have reliability which is not enough, and the interference type optical fiber sensor has higher precision, while the optical fiber fabry-perot (F-P) cavity interferometer has a simple structure, and has been widely researched in recent years. In addition, fiber grating-based level sensors [6], [7] have recently appeared.
The application (patent) No. CN200420102303.6 'optical fiber Fabry-Perot cavity liquid level sensor' uses the influence of the measured liquid level change on the cavity length for sensing. But the manufacturing process is complex and is not suitable for batch production.
In recent years, fiber optic interferometric sensing has been investigated to monitor temperature, pressure, gas density, or refractive index. One way to achieve interference in single mode fibers is to use long period gratings [8], another way to couple light from a single hole fiber to a holey fiber [9], and yet another way to use fiber tapers [10, 11 ]. In 2008, Rajan Jha proposed a photonic Crystal Fiber michelson interferometer for absolute refractive index measurement, which fuses a large-mode field photonic Crystal Fiber (LMA-8 Crystal Fiber) (fig. 1 a) and a single-mode Fiber (SMF-28), and cuts the end of the photonic Crystal Fiber with a Fiber cutter as a mirror surface, wherein interference fringes are red-shifted with the increase of external refractive index, the length of a collapse region formed after fusion splicing is about 300 μm, and a loss is 5-9dB, the loss is related to the length of the collapse region and fusion splicing parameters, and the loss is smaller as the length of the collapse region is shorter [12 ].
In the existing optical fiber liquid level measurement technology, corroded fiber bragg gratings or tapered fibers or optical fiber dislocation welding are adopted for liquid level sensing in various environments, so that the mechanical strength of the optical fibers is reduced, and the use of the optical fibers is limited due to the cross temperature sensitive effect. The liquid level is measured by utilizing the photonic crystal fiber Michelson interferometer, so that the problems can be solved. The mode field intensity ratio of the core mode and the cladding mode which need to participate in interference is more than or equal to 1 when the liquid level is zero, so that the contrast of interference fringes is monotonously reduced along with the increase of the liquid level, and meanwhile, in order to obtain the largest possible measuring range, the loss introduced during welding is about 3 dB. This patent uses SC-4.0 (fig. 1 b) and single mode fiber (SMF-28) fusion splicing, with a small holed cladding portion of SC-4.0, a short collapsed zone after fusion splicing, equal to 65 μm, and a loss introduced by the fusion splicing process of 3 dB. In order to enhance interference signals and prevent silver from entering small holes of the cladding during coating, an optical fiber fusion splicer is used for discharging electricity to the tail end in advance, after air holes are closed, a silver film of 50nm is coated on the tail end of the photonic crystal optical fiber for enhancing reflectivity.
1、 Giovanni Betta,Antonio Pietrosanto, and Antonio Scaglione, "A Digital Liquid Level Transducer Based on Optical Fiber, "IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, 45(2), 551-555(1996).
2、 Pabitra Nath, Pranayee Datta, and Kanak Ch Sarma, "All fiber-optic sensor for liquid level measurement," MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, 50(7), 1982-1984(2008).
3、 Pekka Raatikainen, Ivan Kassamakov, Roumen Kakanakov an Mauri Luukkala, "Fiber-optic liquid-level sensor," sensors and actuators A, 58 93-97(1997).
4、 F. P erez-Oc on , M. Rubino, J.M. Abril, P. Casanova, J.A. Mart nez, " Fiber-optic liquid-level continuous gauge," sensors and actuators A,125,124-132(2006).
5、 Chengning Yang, Shiping Chen, Guoguang Yang, "Fiber optical liquid level sensor under cryogenic environment," sensors and actuators A, 94, 69-75(2001).
6、 Binfeng Yun, Na Chen, and Yiping Cui, "Highly Sensitive Liquid-Level Sensor Based on Etched Fiber Bragg Grating," IEEE PHOTONICS TECHNOLOGY LETTERS, 19(21), 1747-1749(2007).
7、 Tuan Guo, Qida Zhao, Qingying Dou, Hao Zhang, Lifang Xue, Guiling Huang, and Xiaoyi Dong, "Temperature-insensitive fiber Bragg grating liquid-level sensor based on bending cantilever beam," IEEE PHOTONICS TECHNOLOGY LETTERS, 17(11), 2400-2402(2005).
8、 H. J. Patrick, A. D. Kersey, and F. Bucholtz, "Analysis of the response of long period fiber gratings to external index of refraction, " J. Lightw. Technol., 16(9), 1606–1612(1998).
9、 L. Yuan, J. Yang, Z. Liu, and J. Sun, "In-fiber integrated Michelson interferometer, " Opt. Lett., 31(18), 2692–2694(2006).
10、Z. Tian, S. S.-H. Yam, J. Barnes, W. Bock, P. Greig, J. M. Fraser,H. P. Loock, and R. D. Oleschuk, "Refractive index sensingwith Mach–Zehnder interferometer based on concatenating twosingle-mode fiber tapers, " IEEE Photon. Technol. Lett., 20(8), 626–628(2008).
11、Z. Tian, S. S.-H. Yam, and H. P. Loock, "Refractive index sensor basedon an abrupt taper Michelson interferometer in a single mode fiber, "Opt. Lett., vol. 33, 1105–1107( 2008).
12、Rajan Jha, Joel Villatoro,"Ultrastable in reflection photonic crystal fiber modal interferometerfor accurate refractive index sensing, " APPLIED PHYSICS LETTERS, vol.93, 191106(2008)。
Disclosure of Invention
A photonic crystal fiber liquid level sensor is characterized by comprising a single mode fiber SMF-28 and a photonic crystal fiber SC-4.0,
the single-mode fiber SMF-28 is welded with the initial end of the photonic crystal fiber SC-4.0, and the initial end cladding air hole of the photonic crystal fiber is closed at a welding point to form an initial end complete collapse region; the length of the initial fully collapsed region is equal to 65 μm; the tail end of the photonic crystal fiber is welded to form a tail end collapse region; the tail end of the photonic crystal fiber is plated with a reflecting film.
The end-collapsed region may be formed by discharging the end of the photonic crystal fiber with a fusion splicer.
The length of the photonic crystal fiber is 10-50mm as an optimization mode.
The length of the photonic crystal fiber is 20mm as a further optimization mode.
The reflecting film is a metal silver film with the thickness of 50nm as a further optimization mode.
As a further optimization mode, a protective sleeve is arranged outside the photonic crystal fiber liquid level sensor, and a plurality of small holes are formed in the protective sleeve away from the photonic crystal fiber.
A transition buffer sleeve is arranged between the single-mode optical fiber and the protective sleeve as a further optimization mode.
A sensing system that photonic crystal optic fibre level sensor formed which characterized in that: comprises 1510-1590nmASE wide light source, single mode fiber, circulator, photonic crystal fiber sensor, spectrum analyzer and computer; the ASE wide light source is connected with the F port of the circulator, the G port of the circulator is connected with the photonic crystal fiber liquid level sensor, the H port of the circulator is connected with the spectrum analyzer, the data of the spectrum analyzer is read into the computer, and the photonic crystal fiber liquid sensor is vertically arranged in liquid.
A method for manufacturing a photonic crystal fiber liquid level sensor comprises the following steps:
the photonic crystal fiber liquid level sensor is characterized in that a photonic crystal fiber SC-4.0 (shown in figure 1 b) and a common single-mode fiber SMF-28 are welded by a fiber welding machine, a cladding air hole of the photonic crystal fiber at a welding point is completely collapsed to form a collapse region, the length of the collapse region is equal to 65 mu m, 3dB of fiber core loss is introduced, only half of energy is transmitted in the fiber core of the photonic crystal fiber, and the other half of energy which does not enter the fiber core is continuously transmitted in the cladding. Therefore, the collapse region acts as a coupler with the coupling efficiency of 3dB, and light transmitted in a single-mode fiber core is divided into two beams with equal energy to be transmitted in the fiber core and the cladding of the photonic crystal fiber respectively; the end of the optical fiber, which is about 10 to 50mm from the fusion point, is cut with an optical fiber cutter, and the end is discharged with an optical fiber fusion splicer to close the air hole, and then a reflecting film is plated on the end surface as a reflector. The optical fiber Michelson interferometer is formed by a single-mode optical fiber, a welding point, a photonic crystal optical fiber cladding, a photonic crystal optical fiber core and a reflecting film. On the Michelson interferometer, the photonic crystal fiber only has a fiber core and a fiber cladding, and the length of the photonic crystal fiber is 10-50mm, so that the photonic crystal fiber liquid level sensor is formed, and the liquid level of the liquid to be measured is measured by utilizing the light energy loss transmitted in the fiber cladding and the light interference fringe characteristics of the fiber cladding and the fiber core. The refractive index of the measured liquid is larger than that of the photonic crystal fiber cladding.
The sensing principle of the sensor is that the energy loss and the light interference characteristics of the fiber cladding light in the fiber Michelson interferometer at the interface of the photonic crystal fiber and the external environment are utilized to measure the liquid level:
(1) when reaching the fusion point collapse region, the light transmitted in the single-mode fiber core is divided into two parts, one part of the light is continuously transmitted in the photonic crystal fiber core forwards to form a core mold, and the other part of the light is coupled into the photonic crystal fiber cladding and transmitted to form a cladding mold.
(2) When the photonic crystal fiber is placed in air or water or other liquid with the refractive index smaller than that of the photonic crystal fiber cladding, the cladding light is totally reflected at the interface of the cladding and the external environment, and the cladding light energy can be approximately considered as no loss because the length of the photonic crystal fiber is only 10-50 mm.
(3) When a portion or the whole of the photonic crystal fiber is placed in a liquid (such as edible salad oil) having a refractive index greater than that of the photonic crystal fiber cladding, cladding light is reflected and refracted at the interface of the cladding and the external liquid, resulting in attenuation of light energy in the cladding.
(4) When the attenuated cladding light and the fiber core light with unchanged energy reach the reflecting film, the attenuated cladding light and the fiber core light are respectively reflected back to the photonic crystal fiber cladding and the fiber core and are transmitted continuously in the reverse direction. The fiber cladding light continues to reflect and refract. The higher the measured liquid level, the more energy is refracted away. In the above (3) and (4), the object to be measured is the liquid level with the refractive index larger than that of the cladding of the photonic crystal fiber.
(5) When the reflected light of the fiber cladding and the fiber core reaches the fusion point again, the light of the fiber core of the photonic crystal fiber and the light of the fiber cladding of the photonic crystal fiber interfere with each other, and the interference light is transmitted in the single-mode fiber.
(6) In the two beams of light which generate interference, the light in the fiber core of the photonic crystal fiber is not influenced by the external liquid level; however, the light in the cladding of the photonic crystal fiber is refracted to attenuate the energy, but the phase of the light is not changed. This affects the fringe contrast of the interference signal. The higher the liquid level, the more the light energy in the cladding is attenuated, and the smaller the fringe contrast, the relationship of variation between them is determined.
(7) The interference signal is read out by the spectrum analyzer through the circulator. The data of the spectrum analyzer is read into a computer, and the contrast of the interference fringes is calculated, so that the liquid level of the liquid to be measured can be measured.
Principle of spectral coupling in collapsed region of fusion point: (As in fig. 7):
and Z is the light wave transmission distance, the light wave enters a collapse region of the photonic crystal fiber from the single-mode fiber at the position of Z =0, the fundamental mode of the single-mode fiber is diffracted, the mode field is widened, and the mode field diameter MFD can be approximately estimated by a Gaussian beam.
(2)
Wherein
,
Is the optical path difference, I1Is the light intensity propagated in the fiber core and is not influenced by the liquid level change, I2Bag for containing Chinese character' yu
The intensity of light propagating in the layer varies with the level of the liquid being measured. The maximum and minimum light intensities are given by the following two equations
(3)
Where Δ P is the maximum minimum light intensity log difference. When the liquid level varies within a certain range, Δ P will decrease approximately linearly with the liquid level. It can also be seen from the above equation that the liquid level sensing system can eliminate errors due to light source fluctuations and optical path disturbances.
Materials of interest
1. PCF model SC-4.0-1040-46, specific parameters
Material of pure quartz
Refractive index: 1.46
Core diameter of 4.2 +/-0.5 microns
Diameter of the cladding 125 +/-3 mu m
Coating layer diameter of 245 +/-5 mu m
Mode field diameter (MDF) 1550nm 3.4 +/-0.2 microns
Attenuation 1550nm < 2.2 dB/km
2. Specific parameters of SMF-28
Core diameter of 8.2 μm
Diameter of the cladding 125 +/-1 mu m
Coating layer diameter of 250 + -1 μm
Mode field diameter (MDF) 1550nm 9.2 +/-0.8 microns
3. Refractive index of salad oil: 1.47
4. Optical circulator（As in figure 6)
The optical circulator is a three-port non-reciprocal magnetic device and is used for uploading and downloading signals in an optical network. Port F input, port G output; port G input, port H output
Advantageous effects
1. In the existing optical fiber liquid level measurement technology, corroded fiber bragg gratings or tapered fibers or optical fiber dislocation welding are adopted for liquid level sensing in various environments, so that the mechanical strength of the optical fibers is reduced, and the use of the optical fibers is limited due to the cross temperature sensitive effect. The liquid level is measured by utilizing the photonic crystal fiber Michelson interferometer, so that the problems can be solved. The mode field intensity ratio of the fiber core mode and the cladding mode participating in interference is required to be more than or equal to 1 when the liquid level is zero, so that the contrast of interference fringes is monotonously reduced along with the increase of the liquid level, and meanwhile, in order to obtain the largest possible measurement range, the loss introduced when welding is required is about 3 dB. This patent uses SC-4.0 (fig. 1 b) and single mode fiber (SMF-28) fusion splicing, with a small holed cladding portion of SC-4.0, a short collapsed zone after fusion splicing, equal to 65 μm, and a loss introduced by the fusion splicing process of 3 dB. In order to enhance interference signals and prevent silver from entering small holes of the cladding during coating, an optical fiber fusion splicer is used for discharging electricity to the tail end in advance, after air holes are closed, a silver film of 50nm is coated on the tail end of the photonic crystal optical fiber for enhancing reflectivity.
2. The sensor has the advantages of common optical fiber sensors, is not easy to be interfered by electromagnetism, has simple structure and small size, and is suitable for inflammable and explosive severe environments and the like. In addition, the present sensor has a number of unique advantages. (1) The all-fiber Michelson interferometer realizes the functions of light splitting, light transmission, light coupling, reflection, beam combination and interference on the optical fiber, and the sensor structure is miniaturized. (2) The sensing system is not affected by stray light. Because the sensing system measures the interference spectrum signal, and the stray light and the signal light do not meet the coherence condition. Therefore, stray light does not affect the measurement result. (3) The sensing system is not affected by temperature. Because the phase difference between the core light and the cladding light is affected by the temperature change, the interference fringes are translated, but the fringe contrast is not changed. The sensing system measures the contrast of interference fringes, so that the temperature change does not influence the measurement result. (3) The sensor is convenient to manufacture, does not need to corrode an optical fiber, and has low signal noise. In a word, the sensor and the system thereof have simple structure, miniaturization and full optical fiber. The liquid level is measured by using the reflection and refraction of the cladding light of the optical fiber and the interference characteristics of the light, and a complete microstructure Michelson interferometer and a liquid level sensor are realized by using the single-mode optical fiber and the photonic crystal optical fiber, so that the system has high sensitivity and good reliability. The refractive index of the liquid measured by the sensor is larger than that of the cladding of the photonic crystal fiber.
Drawings
FIG. 1a is an end view of a photonic Crystal Fiber LMA-8 Crystal Fiber;
FIG. 1b is an end view of a photonic crystal fiber SC-4.0 used in the present sensor;
FIG. 1c is an end view of a photonic crystal fiber SC-4.0 after the pore has been completely collapsed;
FIG. 2 is a block diagram of a photonic crystal fiber liquid level sensor;
wherein: the optical fiber coating layer comprises an optical fiber coating layer 1, a single-mode optical fiber cladding layer 2, a single-mode optical fiber core 3, a fusion point 4, a photonic crystal optical fiber cladding layer 5, a photonic crystal optical fiber core 6, a reflecting film 7, a protective sleeve 8, end curing glue 9, curing glue 10 and a transition buffer sleeve 11;
FIG. 3 is a schematic structural diagram of a photonic crystal fiber liquid level sensing system;
FIG. 4 is a computer-acquired spectrum of an interference signal in a photonic crystal fiber liquid level sensing system;
FIG. 5 is a graph of the relationship between the level of salad oil and the contrast of interference fringes measured by a photonic crystal fiber optic level sensor;
FIG. 6 is a schematic diagram of an optical circulator with port F input and port G output; port G input, port H output;
FIG. 7 is a schematic diagram of the principle of optical coupling in the collapse region of the fusion point;
Detailed Description
Example 1
The following describes the implementation of the above sensor and system by taking the measurement of the level of salad oil as an example with reference to the accompanying drawings. Other liquid level measurement methods with refractive index larger than the photonic crystal fiber cladding are the same, and the difference is that the liquid level sensing sensitivity of different refractive indexes is different.
A photonic crystal fiber liquid level sensor is characterized by comprising a single mode fiber SMF-28 and a photonic crystal fiber SC-4.0, wherein the single mode fiber SMF-28 is welded with the initial end of the photonic crystal fiber SC-4.0, and a cladding air hole at the initial end of the photonic crystal fiber is closed at a welding point to form a completely collapsed region of the welding point; discharging the tail end of the photonic crystal fiber by using a welding machine to form a tail end collapse area, wherein the tail end is plated with a reflecting film; the length of the collapse area of the welding point is equal to 65 μm. Wherein,
the length of the photonic crystal fiber is 20 mm.
The reflecting film is a metal silver film, and the thickness of the reflecting film is 50 nm.
A protective sleeve is arranged outside the photonic crystal fiber liquid level sensor, and a plurality of small holes are formed in the protective sleeve away from the photonic crystal fiber.
And a transition buffer sleeve is arranged between the single-mode optical fiber and the protective sleeve.
The manufacturing method comprises the following steps:
(1) a single mode fiber (SMF-28, quartz fiber, the diameter of the fiber core is about 8.2 μm, and the diameter of the fiber cladding is 125 μm) and a photonic crystal fiber (SC-4.0, the diameter of the fiber core is about 4.2 μm, and the diameter of the fiber cladding is 125 μm) are welded by a fiber welding machine, the air holes of the photonic crystal fiber cladding 5 are closed at a welding point 4 to form a completely collapsed region, the length of the collapsed region is equal to 65 μm, and the welding point plays the role of a coupler, so that the basic mode of the single mode fiber is divided into the core mode and the cladding mode of the photonic crystal fiber, and the energy of the core mode and the cladding mode is equivalent.
(2) The optical fiber coating layer 1 was coated on the cladding around the fusion-spliced point by an optical fiber coater.
(3) The photonic crystal fiber was cut at a distance of 20mm from the fusion point by a fiber cutter, and the end was discharged by a fiber fusion splicer to close the air holes (FIG. 1 c), and then a 50nm silver metal film was coated on the cut surface as a reflection film 7.
(4) The optical fiber coating layer 1 between the reflection film and the fusion point is removed.
(5) The whole photonic crystal fiber including the single-mode fiber near the welding point is adhered to the inner wall of a protective sleeve 8 with a plurality of small holes by using a curing adhesive 10, and the adhering position of the curing adhesive 10 is close to the end part of the protective sleeve.
(6) A plastic transition buffer 11 is installed at the fiber pigtail end of the protective cover to prevent the fiber from being broken.
(7) The salad oil can contact with the photonic crystal fiber cladding through the small hole, and the liquid level in the protective sleeve, the liquid level of the salad oil and the like are ensured.
(8) When the sensor is taken out of the salad oil, the salad oil in the protective sleeve flows out from the small hole at the tail end.
(9) The protective layer can be omitted, and the sensor can be directly placed in salad oil solution to realize detection.
The photonic crystal fiber liquid level sensing system is constructed as shown in FIG. 3. An ASE light source A with the wavelength of 1510nm-1590nm is input into an F port of a circulator B through an optical fiber F1, passes through a G port of the circulator B and a section of optical fiber F2, and reaches a photonic crystal optical fiber liquid level sensor C. In sensor C, half of the light energy is transmitted in the fiber core of the photonic crystal fiber and is not influenced by the external liquid level change, and the other half of the light energy is coupled into the cladding of the photonic crystal fiber. When the light in the cladding and the fiber core of the photonic crystal fiber reaches the reflecting film, the light is reflected back to the cladding and the fiber core respectively. The light in the cladding generates reflection and refraction at the interface of the optical fiber cladding and the salad oil, only total reflection is carried out at the interface of the optical fiber cladding and the air, and the refracted light can be influenced by the liquid level of the external liquid. When the reflected light reaches the fusion point again, the cladding light of the photonic crystal fiber is coupled into the fiber core of the single-mode fiber, meanwhile, the core light of the photonic crystal fiber is also coupled into the fiber core of the single-mode fiber, and two beams of light in the fiber core of the single-mode fiber generate interference. The returned interference signal light is transmitted to the spectrum analyzer D through the H port of the circulator B and the optical fiber F3. And (3) sending the interference signal spectrum data acquired by the spectrum analyzer into a computer E, and processing the interference signal spectrum data by the computer to obtain and display the salad oil liquid level. The spectral data of the interference signal obtained by the computer is shown in fig. 4 as the interference spectrum when different liquid levels are measured. The measurement and calculation process realizes the calibration of the sensitivity coefficient of the sensor to the salad oil liquid level, and then the salad oil liquid level is tested. The calibrated relationship is shown in fig. 5. During testing, the sensor is vertically placed in the measured salad oil, a computer in the sensing system acquires interference signal spectral data, and the measured salad oil liquid level is calculated according to the calibrated sensitivity coefficient, so that the salad oil liquid level sensing is realized. In this example, the sensitivity of measuring the salad oil level is 0.84dB/mm, and the resolution can reach 0.05 mm.
Claims (5)
1. A photonic crystal fiber liquid level sensor is characterized by comprising a single mode fiber SMF-28 and a photonic crystal fiber SC-4.0, wherein the single mode fiber SMF-28 is welded with the initial end of the photonic crystal fiber SC-4.0, and an initial end cladding air hole of the photonic crystal fiber is closed at a welding point to form an initial end complete collapse area; the length of the initial fully collapsed region is equal to 65 μm; the tail end of the photonic crystal fiber is welded to form a tail end collapse region, and the tail end of the photonic crystal fiber is plated with a reflecting film.
2. The photonic crystal fiber liquid level sensor of claim 1, wherein the length of the photonic crystal fiber is 10-50 mm.
3. The photonic crystal fiber liquid level sensor of claim 2, wherein the length of the photonic crystal fiber is 20 mm.
4. The photonic crystal fiber liquid level sensor of claim 1, wherein the reflective film is a silver film with a thickness of 50 nm.
5. A sensing system formed by a photonic crystal fiber liquid level sensor according to claim 1, wherein: the device comprises a 1510nm-1590nmASE wide light source, a circulator, the photonic crystal fiber liquid level sensor, a spectrum analyzer and a computer; an ASE wide light source is connected with an F port of a circulator, a G port of the circulator is connected with a photonic crystal fiber liquid level sensor, an H port of the circulator is connected with a spectrum analyzer, data of the spectrum analyzer is read into a computer, and the photonic crystal fiber liquid sensor is vertically arranged in liquid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105181325A CN101957227B (en) | 2010-10-22 | 2010-10-22 | Photonic crystal fiber optic liquid level sensor and sensing system formed by same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102261924B (en) * | 2011-04-26 | 2013-02-27 | 南京信息工程大学 | Fabry-Perot interferometric sensor based on solid photonic crystal fiber and manufacturing method thereof |
| CN102778306A (en) * | 2012-07-13 | 2012-11-14 | 南京信息工程大学 | Refractive index and temperature sensor of photonic crystal fiber, manufacturing method and measuring system |
| CN102865946B (en) * | 2012-09-11 | 2014-08-27 | 天津大学 | Photonic crystal fiber temperature sensing probe and measuring system thereof |
| CN102928045B (en) * | 2012-11-26 | 2015-09-09 | 西北大学 | Optical fiber Michelson interference liquid level sensor |
| CN103558663A (en) * | 2013-11-09 | 2014-02-05 | 哈尔滨工业大学 | S-shaped photonic crystal fiber taper sensor and preparing method thereof |
| CN104089682B (en) * | 2014-07-18 | 2018-01-12 | 厦门大学 | A kind of liquid level detection device and its detection method |
| CN104154968A (en) * | 2014-07-23 | 2014-11-19 | 中国计量学院 | Liquid level sensor on basis of fine-core tilted fiber bragg grating |
| CN105157875A (en) * | 2015-06-19 | 2015-12-16 | 中国计量学院 | Temperature sensor based on Michelson interferometer having optical fiber and air ring cavity structure |
| CN105806414B (en) * | 2016-04-26 | 2017-10-31 | 浙江大学 | Optical fiber Temperature Humidity Sensor, temperature and humidity sensing system and humiture demodulation method |
| CN106989795A (en) * | 2017-03-10 | 2017-07-28 | 上海电机学院 | A kind of Hollow-Core Photonic Crystal Fibers liquid level sensor and its making, application method |
| CN108120489A (en) * | 2017-11-24 | 2018-06-05 | 辽宁世达通用航空股份有限公司 | A kind of agricultural sprinkling liquid capacity sensor based on fiber F-P |
| CN109738373A (en) * | 2019-01-22 | 2019-05-10 | 北京信息科技大学 | PH sensor and preparation method thereof based on photonic crystal fiber |
| CN110864762A (en) * | 2019-12-04 | 2020-03-06 | 武汉工程大学 | Input type optical fiber liquid level instrument without installation |
| CN111289473A (en) * | 2020-03-11 | 2020-06-16 | 大连理工大学 | Steel corrosion sensor based on photonic crystal fiber probe |
| CN112763024B (en) * | 2020-12-14 | 2022-08-12 | 北京遥测技术研究所 | Point type optical fiber liquid level sensor |
| CN114279965A (en) * | 2021-12-30 | 2022-04-05 | 中南林业科技大学 | Mach-Zehnder interferometer photonic crystal fiber refractive index sensor and preparation method thereof |
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| CN101303300A (en) * | 2008-05-27 | 2008-11-12 | 重庆大学 | Minitype optical fiber F-P sensor, manufacturing method and liquid tester based on sensor |
| CN101368979A (en) * | 2008-10-13 | 2009-02-18 | 重庆大学 | Miniature full-optical fiber F-P acceleration sensor and preparation thereof |
| CN101561535A (en) * | 2009-05-21 | 2009-10-21 | 浙江大学 | Method for fusing hollow-core photonic crystal fiber and single mode fiber |
| CN101650235A (en) * | 2009-09-11 | 2010-02-17 | 重庆大学 | Minitype optical fiber internal integrated optical fiber interference type temperature sensor and manufacturing method thereof |
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| CN101303300A (en) * | 2008-05-27 | 2008-11-12 | 重庆大学 | Minitype optical fiber F-P sensor, manufacturing method and liquid tester based on sensor |
| CN101368979A (en) * | 2008-10-13 | 2009-02-18 | 重庆大学 | Miniature full-optical fiber F-P acceleration sensor and preparation thereof |
| CN101561535A (en) * | 2009-05-21 | 2009-10-21 | 浙江大学 | Method for fusing hollow-core photonic crystal fiber and single mode fiber |
| CN101650235A (en) * | 2009-09-11 | 2010-02-17 | 重庆大学 | Minitype optical fiber internal integrated optical fiber interference type temperature sensor and manufacturing method thereof |
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