CN111044491A - Trichloromethane evaporation monitoring device and method based on cored D-type single mode fiber - Google Patents

Trichloromethane evaporation monitoring device and method based on cored D-type single mode fiber Download PDF

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CN111044491A
CN111044491A CN201911317934.7A CN201911317934A CN111044491A CN 111044491 A CN111044491 A CN 111044491A CN 201911317934 A CN201911317934 A CN 201911317934A CN 111044491 A CN111044491 A CN 111044491A
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optical fiber
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fiber
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郑华丹
余健辉
朱文国
陈哲
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Jinan University
University of Jinan
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    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/41Refractivity; Phase-affecting properties, e.g. optical path length
    • G01N21/45Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/41Refractivity; Phase-affecting properties, e.g. optical path length
    • G01N21/45Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
    • G01N2021/458Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods using interferential sensor, e.g. sensor fibre, possibly on optical waveguide

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Abstract

The invention discloses a trichloromethane evaporation monitoring device and a monitoring method based on a cored D-type single mode fiber, and the trichloromethane evaporation monitoring device based on the cored D-type single mode fiber comprises a glass substrate, a sample groove arranged on the glass substrate, the cored D-type single mode fiber arranged in the sample groove, a first fiber jumper wire positioned at one end of the cored D-type single mode fiber, and a second fiber jumper wire positioned at the other end of the cored D-type single mode fiber, wherein the first fiber jumper wire is connected with a super-continuous light source, the second fiber jumper wire is connected with a spectrometer, and trichloromethane liquid is filled in the sample groove. The trichloromethane evaporation monitoring device and the monitoring method based on the depoling D-type single-mode optical fiber can continuously monitor the trichloromethane volatilization process on line in real time, have ultrahigh sensitivity and quick response capability, and have huge application potential in real-time monitoring in the fields of analytical chemistry and industry.

Description

Trichloromethane evaporation monitoring device and method based on cored D-type single mode fiber
Technical Field
The invention relates to the field of monitoring of a trichloromethane evaporation process, in particular to a trichloromethane evaporation monitoring device and a trichloromethane evaporation monitoring method based on a cored D-type single mode fiber.
Background
Chloroform of the formula CHCl3A volatile liquid, colorless, having a sweet taste, is an important organic compound in organic industrial chemistry and biology. Released from various artificial sources into the environment during the gas production process, under the illumination condition, the trichloromethane interacts with oxygen in the air and is gradually decomposed into highly toxic phosgene. Even if the contact time is short, 50ppm (volume fraction is 10)-6) Trichloromethane may also cause damage to human health. The analytical method for detecting trichloromethane comprises a spectrophotometer, metal oxide and long-period fiber grating. The photometer may be used as a useful tool for measuring the refractive index. However, these methods are not suitable for online on-site monitoring, which has the disadvantages of being bulky and slow to sample.
Refractive index sensors based on optical fibers have the advantages of no electromagnetic interference, compact structure, high sensitivity and the like, and have been widely studied in the past. In the optical fiber sensor, multimode interference is an effective method for improving the detection sensitivity, and the method has been studied in recent years. The multimode interference in the optical waveguide refers to mutual interference of light among all guided modes, which causes the optical field distribution on the section of the optical fiber to periodically change along the longitudinal transmission distance. The ambient refractive index affects multimode interference effects in the optical waveguide and the transmission spectrum. Multimode interference plays an important role in the fields of optical fiber sensors, couplers, optical filters, fiber lasers, and the like. Since the change of the refractive index of the optical fiber refractive index sensor based on the multimode interference is related to the frequency shift of the multimode interference, it is required to efficiently excite a higher-order mode and a strong spectral shift in the multimode waveguide. A variety of optical fiber sensors, such as a core-removed optical fiber, a tapered optical fiber, and a micro-core optical fiber, have been reported, in which a side-polished optical fiber is an optical fiber manufactured by polishing a section of a cladding of an optical fiber using an optical micromachining technique. The cladding portion of the single mode fiber was side polished to leave the remaining cladding layer as a D-type multimode waveguide, and the cladding thickness of the fiber was polished to a core region of only a few microns to produce a side-polished fiber. Light propagating in the core region will leak out in the form of a evanescent wave field, creating strong interactions with the external medium. According to the principle that the side polished optical fiber based on multimode interference is sensitive to the environment refractive index, the measured material is placed in the side polished area, so that the evanescent wave field can interact with the material, and the side polished optical fiber provides an effective platform for refractive index sensing. The side-polished single-mode-multimode-single-mode optical fiber, the multi-D type optical fiber and the side-polished plastic optical fiber are several refractive index sensors based on multimode interference reported according to the multimode interference principle and the D type structure. However, most D-fibers are based on multimode fibers or plastic fibers with large cores, which are costly.
Disclosure of Invention
The invention aims to overcome at least one defect of the prior art and provides a trichloromethane evaporation monitoring device based on a depoling D-type single-mode optical fiber, which can continuously monitor the volatilization process of trichloromethane on line in real time, has high sensitivity and high reaction speed, and has great application potential in real-time monitoring in the fields of analytical chemistry and industry.
Another object of the present invention is a method for monitoring chloroform evaporation based on a core-removed D-mode single-mode fiber, which has ultra-high sensitivity and fast response capability.
The technical scheme adopted by the invention is as follows:
the utility model provides a trichloromethane evaporation monitoring devices based on D type single mode fiber that cores, including the glass base plate, locate the sample groove on the glass base plate, arrange the D type single mode fiber that cores in the sample groove in, be located the first optic fibre wire jumper of D type single mode fiber one end that cores, be located the second optic fibre wire jumper of the D type single mode fiber other end that cores, first optic fibre wire jumper is connected with super continuous light source, the second optic fibre wire jumper is connected with the spectrum appearance, the sample groove is equipped with the trichloromethane liquid in.
The basis of an optical fibre refractive index sensor is the interaction between an analyte in the optical fibre and the evanescent wave field. In order to obtain an evanescent wave field, a portion of the fiber cladding must be removed, which may be done by fiber melting and tapering techniques, fiber side polishing techniques, and femtosecond laser pulse techniques. The prior literature reports a number of various sensors based on side polished optical fibers, such as fiber couplers, modulators, attenuators, switching stages, humidity sensors and temperature sensors. However, the prior art reports only partial removal of the fiber cladding. The invention is based on the removal condition of the whole fiber core, and is called a core-removing D-type single-mode fiber, and the core-removing D-type single-mode fiber can be used as a sensor for monitoring the trichloromethane evaporation condition in real time.
The core-removing D-type single-mode optical fiber comprises a core-removing plane, a transition leading-in part, a transition leading-out part, an optical fiber leading-in part and an optical fiber leading-out part, wherein the transition leading-in part is positioned on one side of the core-removing plane, the transition leading-out part is positioned on the other side of the core-removing plane, the optical fiber leading-in part is connected with the transition leading-in part, the optical fiber leading-out part is connected with the transition leading-out part, the height difference between the plane where the optical fiber leading-in part. The cored flat portion serves as a D-type multimode waveguide; the curved polished surface of the transition lead-in provides an efficient method of exciting higher order modes by multiple reflections and scattering; the strong evanescent field of the polished surface of the optical fiber provides a high-sensitivity sensing area for the ambient refractive index; the core in the transition lead-out portion collects light from the cored-out planar section for output measurement.
Preferably, the residual thickness is 34.09 μm.
Preferably, the optical fiber leading-in part and the optical fiber leading-out part are fixed on the glass substrate through ultraviolet glue.
A trichloromethane evaporation monitoring method based on a core-removing D-type single mode fiber comprises the following steps:
(1) using a precisely controlled wheel type side polishing and grinding system, and enabling the transmitted light power to reach-75 dBm of the lower limit of the optical power measuring range through pretreatment and a polishing and grinding process of 300r/min to obtain a cored D-type single-mode optical fiber, wherein the cored D-type single-mode optical fiber comprises a cored plane, a transition leading-in part positioned on one side of the cored plane, a transition leading-out part positioned on the other side of the cored plane, an optical fiber leading-in part connected with the transition leading-in part, and an optical fiber leading-out part connected with the transition leading-out part, and the height difference between the plane where the optical fiber leading-in part is positioned and the cored plane is the residual thickness, so that 5 kinds of cored D-type single-mode optical fibers with different residual thicknesses are prepared, and the residual thicknesses are respectively 54.9 micrometers, 50.9 micrometers, 46.3 micrometers, 39.4 micrometers and;
(2) cleaning the surface of an optical fiber by using alcohol, fixing an optical fiber leading-in part and an optical fiber leading-out part of a decored D-type single mode optical fiber on a glass substrate by using ultraviolet glue, fixing the optical fiber leading-in part and the optical fiber leading-out part on the glass substrate, connecting a first optical fiber jumper wire to a supercontinuum light source (SCSYSLSC-5-CFS), connecting a second optical fiber jumper wire to a spectrometer (OSA YOKOGAW AQ6370D), arranging a sample groove filled with trichloromethane standard refractive index liquid on the glass substrate, and completely immersing;
(3) taking trichloromethane standard refractive index liquid with the refractive index range of 1.430-1.444 as a standard sample for evaluating a sensor based on the depoling D-type single-mode optical fiber, adding 10 mu L of refractive index liquid into a sample groove each time, recording the transmission spectrum of the corresponding depoling D-type single-mode optical fiber, and cleaning the depoling D-type single-mode optical fiber with alcohol before the next test;
(4) calculating the sensitivity of the 5 types of core-removed D-type single-mode fibers with different residual thicknesses in different refractive index ranges to obtain the inverse ratio of the sensitivity of the sensor to the residual thickness of the core-removed D-type single-mode fiber; the sensitivity of the screened core-removed D-type single-mode optical fiber with the residual thickness of 34.09 mu m is optimal;
(5) and (3) carrying out evaporation monitoring on the trichloromethane to be monitored by using the depoling D-type single mode optical fiber with the residual thickness of 34.09 mu m according to the method in the step (2).
According to the invention, 5 types of core-removed D-type single-mode fibers with different residual thicknesses are manufactured through side polishing, then the core-removed D-type single-mode fibers are used for testing standard refractive index liquids with different refractive indexes to obtain transmission spectra, the sensitivities of the 5 types of core-removed D-type single-mode fibers with different residual thicknesses in different refractive index ranges are calculated, so that the core-removed D-type single-mode fibers with the best sensitivity are screened out, a trichloromethane evaporation device based on the core-removed D-type single-mode fibers can be assembled by using the screened core-removed D-type single-mode fibers, trichloromethane liquid is placed in a sample tank, and trichloromethane evaporation monitoring can be carried out in real time.
Preferably, the standard refractive index liquid in step (2) is a chloroform liquid having a height of 5 mm.
Compared with the prior art, the invention has the beneficial effects that: the invention discloses a trichloromethane evaporation monitoring device and a monitoring method based on a decored D-type single-mode optical fiber, wherein a trichloromethane volatilization process can be continuously monitored on line in real time by using a decored D-type single-mode optical fiber sensor, and the device has ultrahigh sensitivity and quick response capability, thereby indicating that the decored D-type single-mode optical fiber has huge application potential in real-time monitoring in the fields of analytical chemistry and industry.
Drawings
Fig. 1 is a cross-sectional structure comparison diagram of a conventional single mode optical fiber and a core-removed D-mode optical fiber.
FIG. 2 is a schematic view of a core-removed D-mode single-mode fiber.
FIG. 3 is SEM, optical microscope and AFM images of a core-removed D-mode single mode fiber.
Fig. 4 is a diagram of an optical transmission path in a core-removed single-mode optical fiber.
FIG. 5 is a microscopic image of the polished area of a stripped D-mode single mode fiber of various residual thicknesses taken by an optical microscope.
Fig. 6 is a schematic structural diagram of a trichloromethane evaporation monitoring device based on a core-removed D-type single mode fiber.
FIG. 7 is an experimental and theoretical transmission spectrum of a stripped D-mode single mode fiber of varying residual thickness.
FIG. 8 is a graph showing the relationship between the characteristic peak wavelength and the standard refractive index of a core-removed D-mode single-mode optical fiber and the sensitivity of a sensor.
FIG. 9 is a test chart showing the results of the chloroform evaporation process.
Description of the drawings: 1-a supercontinuum light source; 2-a first optical fiber jumper; 3-core-removing D-type optical fiber module; 31-a fiber introduction portion; 32-a transition introduction section; 33-coring plane; 34-a transition lead-out portion; 35-fiber lead-out part; 4-a second optical fiber jumper; 5-a spectrometer; 6-standard refractive index liquid; 7-a glass substrate; 8-sample tank.
Detailed Description
The drawings are only for purposes of illustration and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
FIG. 1 is a schematic cross-sectional view of a conventional side-polished optical fiber (FIG. 1a) and a Core-removed D-mode optical fiber (FIG. 1b), in which the vertical dimension from the polished surface to the optical fiber surface is referred to as the residual thickness RT (residual thickness) in FIG. 1, and the residual thickness RT is an important parameter for determining the interaction strength of the evanescent wave field with the external medium, this embodiment is based on the removal of the entire Core, and the Cladding (Cladding) and the Core (Core) can be polished by a precisely controlled optical fiber manufacturing system to obtain the Core-removed D-mode optical fiber, as shown in FIG. 2, which is a schematic structural view of the Core-removed D-mode optical fiber, wherein FIG. 2a is a schematic structural view of the Core-removed D-mode optical fiber, and FIG. 2 b is a side view of the Core-removed D-mode optical fiber, and the Core-removed D-mode optical fiber comprises a Core-removing plane 33, a transition lead-in portion 32, a transition lead-in portion on one side, A transition lead-out portion 34 on the other side of the coring plane, a fiber lead-in portion 31 connected to the transition lead-in portion, and a fiber lead-out portion 35 connected to the transition lead-out portion. The cored flat portion serves as a D-type multimode waveguide; the curved polished surface of the transition lead-in provides an efficient method of exciting higher order modes by multiple reflections and scattering; the strong evanescent field of the polished surface of the optical fiber provides a high-sensitivity sensing area for the ambient refractive index; the core in the transition lead-out portion collects light from the cored-out planar section for output measurement. For the core-removed D-mode single-mode fiber, the vertical dimension from the polished surface (polished surface) to the fiber surface corresponds to the height difference between the plane of the fiber lead-in portion and the core-removed plane.
FIG. 3a is an end view of a core-removed D-mode single-mode fiber taken by a Scanning Electron Microscope (SEM), FIG. 3b is a polished area of the core-removed D-mode fiber taken by an optical microscope (Zeiss, Axio Scope A1) with a 20-fold objective lens, and FIG. 3c is a1 × 1 μm image of a polished portion of the core-removed single-mode fiber taken by an Atomic Force Microscope (AFM) with a data resolution of 5k × 5k pixels. In the embodiment, the protrusion of the polished area of the core-removed single-mode fiber is less than 3.5nm, and the surface of the manufactured core-removed D-type single-mode fiber slice is smooth.
The optical transmission path in the core-removed D-mode single-mode optical fiber is shown in fig. 4. The higher order in the fiber is caused by multiple reflections on the curved facets in the transition lead-in portion, the multimode interference efficiency in the decored single mode fiber is closely related to the residual thickness, and the coreless D-fibers with different residual thicknesses have different incident angles θ.
The process of monitoring the chloroform evaporation based on the core-removing D-type single-mode fiber in the embodiment is as follows:
(1) the method comprises the steps of using a wheel type side polishing system which is accurately controlled to enable the transmitted light power to reach the lower limit of the measuring range of an optical power meter to be-75 dBm through pretreatment and a polishing process of 300r/min, obtaining the core-removed D-type single-mode optical fiber, wherein the polishing process comprises five minutes of rough polishing to manufacture the side polishing optical fiber, and in addition, 90 minutes of fine polishing work is carried out. The core-removing D-type single-mode optical fiber comprises a core-removing plane 33, a transition leading-in part 32 located on one side of the core-removing plane, a transition leading-out part 34 located on the other side of the core-removing plane, an optical fiber leading-in part 31 connected with the transition leading-in part, and an optical fiber leading-out part 35 connected with the transition leading-out part, wherein the height difference between the plane where the optical fiber leading-in part is located and the core-removing plane is the residual thickness. Since the sensitivity of the core-removed D-mode single-mode fiber is closely related to the residual thickness of the fiber, 5 core-removed D-mode single-mode fibers having different residual thicknesses of 54.9 μm, 50.9 μm, 46.3 μm, 39.4 μm, and 34.09 μm, respectively, were prepared, and the polished area microscopic image thereof is shown in fig. 5.
(2) Cleaning the surface of the optical fiber by using alcohol, fixing an optical fiber leading-in part 31 and an optical fiber leading-out part 35 of the core-removed D-type single-mode optical fiber on a glass substrate by using ultraviolet glue, fixing the optical fiber leading-in part and the optical fiber leading-out part on the glass substrate 7, connecting a first optical fiber jumper 2 to a supercontinuum light source (SCS YSLSC-5-CFS)1, connecting a second optical fiber jumper 4 to a spectrometer (OSA YOKOGAW AQ6370D)5 with the resolution of 20pm, wherein the wavelength range of the supercontinuum light source 1 is 450nm-2400nm, and the peak power is 9dBm at the wavelength of 106; the glass substrate 7 is provided with a sample tank 8 filled with chloroform standard refractive index liquid 6, and the transition leading-in part 32, the coring plane 33 and the transition leading-out part 34 are completely immersed in the standard refractive index liquid 6, as shown in fig. 6.
(3) Taking trichloromethane standard refractive index liquid with the refractive index range of 1.430-1.444 as a standard sample for evaluating a sensor based on the depoling D-type single-mode optical fiber, adding 10 mu L of refractive index liquid into a sample groove each time, recording the transmission spectrum of the corresponding depoling D-type single-mode optical fiber, and cleaning the depoling D-type single-mode optical fiber with alcohol before the next test;
(4) the refractive index sensing performance of the core-removed D-type single mode optical fibers with five different residual thicknesses is theoretically and experimentally evaluated, the residual thicknesses of 54.9 microns, 50.9 microns, 46.3 microns, 39.4 microns and 34.1 microns are shown in the graphs of FIGS. 7(a), (c), (e), (g) and (i), the transmission spectra with the refractive index range of 1.430-1.444 are shown, and the transmission spectra with the refractive index range of 1.430-1.444 are shown in the graphs of FIGS. 7(b), (D), (f), (h) and (j), which are obtained by simulation. And simulating the transmission spectrum and the light field evolution of the cored D-type single mode fiber by adopting an Rsoft software light beam propagation module. In this example, the length of the coring plane is 8mm, the length of the transition lead-in/transition lead-out is 4mm, the core refractive index is 1.4681, the cladding refractive index is 1.4628, the inner diameter of the fiber is 8.2 μm, and the cladding diameter is 125 μm. The residual thicknesses in the simulation were set to 35 μm, 40 μm, 45 μm, 50 μm and 55 μm, respectively, to analyze that the core-removed D-mode single-mode fibers of different residual thicknesses have different multimode interference efficiencies. The curved polishing surfaces of transition section 1 (transition lead-in section) and transition section 2 (transition lead-out section) were modeled by a surface of an elliptical cylinder with a major axis Lt1 and a minor axis (125-RT) μm. As the index of refraction increases, the characteristic valley shifts to the long wavelength side as the growth rate increases. FIG. 8a is a graph showing the relationship between the characteristic peak wavelength and the standard refractive index of a core-removed single-mode optical fiber, and we can observe the shift of the characteristic valley according to the characteristic valley indicated by the arrow in FIG. 8 and obtain the correlation between the wavelength corresponding to the characteristic valley and the surrounding refractive index. Fig. 8(a) shows the characteristic valley wavelength for the effect of the experimentally obtained ambient refractive index from 1.305 to 1.444, which increases exponentially with the ambient refractive index. In the range of the refractive index value of 1.430-1.444, when the refractive index value is close to the fiber core, the slope change of the curve is obvious. The strong evanescent wave generated by the fiber core on the polished surface of the optical fiber leads to a higher refractive index when the planar part of the core-removed part interacts with the environmental refraction filtrate. As shown in fig. 8(b), the sensitivities of the 5 types of core-removed D-mode single-mode fibers with different residual thicknesses in different refractive index ranges are calculated, and the obtained sensor sensitivity is inversely proportional to the residual thicknesses of the core-removed D-mode fibers. For a residual thickness of 34.09 μm, a sensor sensitivity in the refractive index range of 1.305-1.402 reached 487nm/RIU, which is 2.8 times greater than the sensitivity of 54.85 μm. In the range of 1.430-1.444, the sensitivity of the sensor is as high as 10243nm/RIU, so that the sensitivity of the core-removed D-type single-mode optical fiber with the residual thickness of 34.09 mu m is screened out to be the best.
(5) And (3) carrying out evaporation monitoring on the trichloromethane to be monitored by using the depoling D-type single mode optical fiber with the residual thickness of 34.09 mu m according to the method in the step (2). The spectrometer was used to record spectra, the characteristic valley wavelength monitoring of the spectrum from 1250nm to 1600n was followed in real time, recording once per minute, yielding 1750 points. Fig. 9(a) is a graph of the change in transmission spectrum throughout the volatilization of chloroform, with a sharp red shift of the characteristic valley wavelength of the sensor to greater than 1550nm over 30 minutes and a gradual blue shift to about 1450nm over 2 hours. Fig. 9(b) depicts the shift change of the sensor transmission spectrum. For comparison, the transmission spectrum of a chloroform-free sensor was recorded at T-0, and Δ λ was defined as the shift in the characteristic valley wavelength. Dividing FIG. 9(b) into four regions according to the volatilization process of the chloroform liquid. Zone a and zone D represent the process of immersion and separation of the fiber in liquid chloroform. Immersion in chloroform results in a wavelength red shift of approximately 175nm compared to fiber optic sensors in air. The volatility of chloroform causes the transmission spectrum of the fiber optic sensor to shift. In zone B, from 6min to 27min, the trough wavelength shifts to a longer wavelength, Δ λ, 267.6nm, which is caused by the volatilization of alcohol in the chloroform mixture. In zone C, the chloroform begins to volatilize and causes a blue shift in the characteristic valley wavelength. Within 128min, the chloroform was completely separated from the fiber optic sensor. Impurities of the liquid mixture adhering to the fiber cause small deviations between the start and the end of the characteristic valley wavelength.
In the embodiment, a core-removed D-shaped structure is manufactured on a single-mode optical fiber, and the manufactured side polishing system is used for realizing high-sensitivity refractive index sensing. Compared with other D-type optical fiber sensors, the D-type structure developed by the people adopts the common communication single-mode optical fiber, the cladding and the fiber core of the single-mode optical fiber are processed by a simple grinding wheel, and the loss of the fiber core causes multiple reflection and multimode interference in the D-type optical fiber waveguide. Research results show that the residual thickness of the core-removed D-mode single-mode fiber has a significant influence on the transmission spectrum of the fiber. Therefore, we fabricated five different residual thicknesses on different D-mode single mode fibers to evaluate the performance of the sensor. The results show that the sensitivity of the fiber sensor is inversely proportional to the residual thickness of the D-mode single mode fiber. When the residual thickness is 34.09 μm and is in the range of 1.43-1.44, the extinction ratio reaches about 15dB, the sensitivity reaches 10243nm/RIU, and the refraction resolution can reach 1.9 multiplied by 10-6 RIU. Therefore, the use of the core-removing D-type single-mode fiber sensor can continuously monitor the volatilization process of the trichloromethane on line in real time, and has ultrahigh sensitivity and quick response capability, which shows that the core-removing D-type single-mode fiber has great application potential in the real-time monitoring in the fields of analytical chemistry and industry.
It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific embodiments of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention claims should be included in the protection scope of the present invention claims.

Claims (6)

1. The utility model provides a chloroform evaporation monitoring devices based on D type single mode fiber that cores, a serial communication port, including the glass substrate, locate the sample groove on the glass substrate, arrange the D type single mode fiber that cores in the sample groove, be located the first optic fibre wire jumper of D type single mode fiber one end that cores, be located the second optic fibre wire jumper of the D type single mode fiber other end that cores, first optic fibre wire jumper is connected with super continuous light source, second optic fibre wire jumper is connected with the spectrum appearance, the chloroform liquid is equipped with in the sample groove.
2. The chloroform evaporation monitoring device based on the depoling D-type single-mode optical fiber, according to claim 1, wherein the depoling D-type single-mode optical fiber comprises a depoling plane, a transition leading-in part positioned on one side of the depoling plane, a transition leading-out part positioned on the other side of the depoling plane, an optical fiber leading-in part connected with the transition leading-in part, and an optical fiber leading-out part connected with the transition leading-out part, wherein the height difference between the plane where the optical fiber leading-in part is positioned and the depoling plane is a residual thickness, and the residual thickness is 34 μm-55 μm.
3. The apparatus according to claim 2, wherein the residual thickness is 34.09 μm.
4. The trichloromethane evaporation monitoring device based on the depoling D-type single mode fiber according to claim 1, wherein the fiber leading-in part and the fiber leading-out part are fixed on the glass substrate through ultraviolet glue.
5. A trichloromethane evaporation monitoring method based on a core-removing D-type single mode fiber is characterized by comprising the following steps:
(1) using a precisely controlled wheel type side polishing and grinding system, and enabling the transmitted light power to reach-75 dBm of the lower limit of the optical power measuring range through pretreatment and a polishing and grinding process of 300r/min to obtain a cored D-type single-mode optical fiber, wherein the cored D-type single-mode optical fiber comprises a cored plane, a transition leading-in part positioned on one side of the cored plane, a transition leading-out part positioned on the other side of the cored plane, an optical fiber leading-in part connected with the transition leading-in part, and an optical fiber leading-out part connected with the transition leading-out part, and the height difference between the plane where the optical fiber leading-in part is positioned and the cored plane is the residual thickness, so that 5 kinds of cored D-type single-mode optical fibers with different residual thicknesses are prepared, and the residual thicknesses are respectively 54.9 micrometers, 50.9 micrometers, 46.3 micrometers, 39.4 micrometers and;
(2) cleaning the surface of an optical fiber by using alcohol, fixing an optical fiber leading-in part and an optical fiber leading-out part of a decored D-type single mode optical fiber on a glass substrate by using ultraviolet glue, fixing the optical fiber leading-in part and the optical fiber leading-out part on the glass substrate, connecting a first optical fiber jumper to a super-continuous light source, connecting a second optical fiber jumper with a spectrometer, arranging a sample tank filled with trichloromethane standard refractive index liquid on the glass substrate, and completely immersing the transition leading;
(3) taking trichloromethane standard refractive index liquid with the refractive index range of 1.430-1.444 as a standard sample for evaluating a sensor based on the depoling D-type single-mode optical fiber, adding 10 mu L of refractive index liquid into a sample groove each time, recording the transmission spectrum of the corresponding depoling D-type single-mode optical fiber, and cleaning the depoling D-type single-mode optical fiber with alcohol before the next test;
(4) calculating the sensitivity of the 5 types of core-removed D-type single-mode fibers with different residual thicknesses in different refractive index ranges to obtain the inverse ratio of the sensitivity of the sensor to the residual thickness of the core-removed D-type single-mode fiber; the sensitivity of the screened core-removed D-type single-mode optical fiber with the residual thickness of 34.09 mu m is optimal;
(5) and (3) carrying out evaporation monitoring on the trichloromethane to be monitored by using the depoling D-type single mode optical fiber with the residual thickness of 34.09 mu m according to the method in the step (2).
6. The trichloromethane evaporation monitoring method based on the depoling D-type single mode fiber according to claim 5,
and (3) the standard refractive index liquid in the step (2) is trichloromethane liquid with the height of 5 mm.
CN201911317934.7A 2019-12-19 2019-12-19 Trichloromethane evaporation monitoring device and method based on cored D-type single mode fiber Pending CN111044491A (en)

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