CN207741874U - Based on the cascade 2 ocean temperature sensors of thin-core fibers and standard single-mode fiber - Google Patents
Based on the cascade 2 ocean temperature sensors of thin-core fibers and standard single-mode fiber Download PDFInfo
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- CN207741874U CN207741874U CN201820164622.1U CN201820164622U CN207741874U CN 207741874 U CN207741874 U CN 207741874U CN 201820164622 U CN201820164622 U CN 201820164622U CN 207741874 U CN207741874 U CN 207741874U
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Abstract
The utility model discloses one kind being based on thin-core fibers and the cascade 2 ocean temperature sensors of standard single-mode fiber, including the first single mode optical fiber, the first thin core single mode optical fiber and the second single mode optical fiber being sequentially connected, the front end of the first thin core single mode optical fiber and the rear end of the first single mode optical fiber are welded together with misplacing, and the rear end of the first thin core single mode optical fiber is welded together with the front end dislocation-free of the second single mode optical fiber.Dislocation-free welding has the second thin core single mode optical fiber and third single mode optical fiber successively for the rear end of second single mode optical fiber.The utility model can measure quasi-continuous 2 ocean temperatures, and measure accurate high sensitivity, and favorable repeatability, two temperature measuring points are apart from adjustable in a certain range.
Description
Technical field
The utility model belongs to strain detecting technical field, and in particular to one kind being based on thin-core fibers and standard single-mode fiber
Cascade quasi-continuous 2 ocean temperature sensors.
Background technology
The temperature of seawater is also seawater typically as a physical quantity to the cold and hot performance response of marine climate
One important feature.Therefore, the temperature change research of seawater occupies highly important status in the research of Marine Sciences.Research
The variation of ocean temperature is both an oceanologic important research content, also to climate change, Marine Sciences, sea fishery and
The development of the subjects such as underwater sound science has very important significance.Previous research focuses mostly in the process of big space scale,
It is not high to the spatial resolution requirements of ocean wave parameter.However, being investigated further with to ocean, it has been found that many parameters are very
It changes in small spatial dimension, this may have close association with large-scale oceanographic phenomena, such as a small range temperature
Distribution and its variation can reflect heat exchange and substance cycle that air-sea interaction and turbulent mixing process occur.Separately
Outside, temperature creep stress of the lamination on bed boundary also differs widely in interior wave.Therefore, two or more standards in seawater are measured to connect
The temperature of continuous point would be possible to disclose the mechanism that heat exchange and substance cycle occur in ocean-atmosphere interaction, be ground for fining ocean
Study carefully and valuable reference is provided, and to realize quasi-continuous 2 thermometrics and generally require detection method and have space less than centimetres
The ability that resolution ratio and Multipoint synchronous measure.
Currently, the most common method for measuring ocean temperature, mainly there is thermistor, thermocouple sensor thermometric and satellite
The methods of remote sensing thermometric.But these measurement methods have certain limitation：Thermistor (temperature) sensor thermometric needs periodic cleaning
To ensure its accuracy measured；Thermocouple measurement precision can only achieve the measurement accuracy with reference to junction temperature, generally at 1 DEG C
To in 2 DEG C；Satellite remote sensing thermometric needs to rely on satellite, larger to reception technique and hardware and software requirement, and electromagnetic wave cannot penetrate
Sea, measurement accuracy be not high.
Compared with above-mentioned typical ocean temperature detection method, optical fiber is since own vol is small, entire device size
Smaller advantage is particularly suited for solving the problems, such as this.The principle of full-fiber sensor thermometric be according to the refractive index of seawater and
Ocean temperature relationship, in conjunction with the thermo-optical coeffecient of fiber optic materials, the calculating of application experience formula can be obtained accurate sea water temperature
Angle value facilitates on-line checking, and does not cause any secondary pollution to seawater, therefore receives significant attention.The seawater reported at present
Temperature full-fiber sensor mainly has fiber grating, conical fiber and micro optical fiber ring resonator etc., these sensors all have
Special structure needs complicated preparation process, and the sensor structure having is more fragile, and sensitivity is nor very high.
That reports recently has higher measurement sensitivity based on hollow multiple-mode interfence sensor, can also be applied to the survey of ocean temperature
Amount, but its cost is higher, sensor preparation process is also complex, therefore limits its use.
106802190 A of patent of invention CN disclose a kind of optic fibre turning sensor of highly sensitive no Temperature cross-over interference,
Including the first single mode optical fiber, the first thin-core fibers, taper thin-core fibers, the second thin-core fibers and the second single mode optical fiber；Described
One end of one single mode optical fiber is connected with the first thin-core fibers, and for misplaces fusion point between the two as the first fusion point, dislocation is molten
It connects for being coupled to the light transmitted in the first single mode optical fiber is more average in the fibre core and covering of the first thin-core fibers；It is another
End is for external wide source light source；The fibre core optically coupling to the first thin-core fibers that first single mode optical fiber is used to send out wideband light source
In；The taper thin-core fibers are located between first thin-core fibers and second thin-core fibers, are used for the first thin core
In the light partial compromise to external environment transmitted in the covering of optical fiber；The other end connection described second of second thin-core fibers
One end of single mode optical fiber, as the second fusion point, dislocation welding is used for the second thin-core fibers misplaces fusion point between the two
Middle fibre core and the light of covering transmission more average are coupled in the fibre core of the second single mode optical fiber；Second single mode optical fiber it is another
One end, as the external spectrometer of output end；First fusion point and second fusion point be symmetrical using shaft axis of optic fibre direction,
The welding mode of cross-wise direction dislocation, optical fiber is formed together with the first thin-core fibers, taper thin-core fibers and the second thin-core fibers
Liriodendron chinese structure in line, the first and second thin-core fibers and the first and second single mode optical fiber axis direction symmetrically make described thin
The cladding mode number being excited in core fibre is relatively fewer, can be formed after interfering with thin-core fibers fibre core formation mode more pure
Net interference pattern can make to be assigned to the thin-core fibers in fusion process perpendicular to the dislocation of the cross-wise direction of optical axis
The light intensity of middle fibre core and covering is more average.The sensor sensitivity height of the invention, dynamic range are big, but also with structure letter
Single, cheap, the advantages that being easily integrated.But the sensor of the invention can only measure the temperature change of a single point, and should
The structure of sensor is insecure to be easy to be destroyed by external disturbance, in addition, the thin-core fibers used in the sensor of the invention are adopted
It is made of flame stretching method, manufacturing process is not easy to repeat there are contingency.
All -fiber Mach-Zehnder types interferometer (hereinafter referred to as MZI) has simple in structure firm, compact, makes
Simply, of low cost, the advantages that electromagnetism interference, it has been widely used in straining, temperature, refractive index, level sensing and biology
The fields such as medical treatment.But it is only used for a point or two point (distances apart from each other currently based on the temperature sensing of MZI
Typically larger than 20cm).It is two based on standard single-mode fiber and the cascade Mach Zehnder interferometer temperature sensor of thin-core fibers
The middle one section thin core single mode optical fiber of access effectively inspires packet by the unmatched structure of fibre core between section general single mode fiber
The light wave of layer model, and generate interference with core mode.For the above-mentioned this sensor for only accessing one section of thin-core fibers, work as seawater
Temperature change it is smaller when, no matter the thin-core fibers core diameter of access and length how much, can all exist or interference peaks in transmission spectrum
Be worth wavelength knots modification is relatively low compared with sluggishness or spectral extinction smaller the problems such as being not easy to differentiate peak shifting amount, and can only all survey
Measure the temperature of single-point seawater.Two temperature of distance farther out are only used for if even if two the sensors are connected
Sensing, and the spectrum after connecting is since the direct superposition of two sets interference signals is easy to become confusion and is difficult to demodulation and analyzes.
Therefore all -fiber MZI that can be used for quasi-continuous 2 temperature sensing of seawater is urgently developed.
Invention content
In view of the deficiencies of the prior art, the utility model provides a kind of based on thin-core fibers and standard single-mode fiber cascade
2 ocean temperature sensors, the technical issues of to solve quasi-continuous 2 temperature sensing in seawater, sensor structure letter
Single, mechanical strength is also preferable, and it is accurate to measure, high sensitivity, favorable repeatability and has certain flexibility.
To achieve the above object, the technical solution of the utility model is a kind of based on thin-core fibers and standard single-mode fiber grade
2 ocean temperature sensors of connection, including the first single mode optical fiber, the first thin core single mode optical fiber and the second single mode that are sequentially connected
Optical fiber, the front end of the first thin core single mode optical fiber are welded together with misplacing with the rear end of the first single mode optical fiber, and described first
The rear end of thin core single mode optical fiber is welded together with the front end dislocation-free of the second single mode optical fiber；After second single mode optical fiber
Dislocation-free welding has the second thin core single mode optical fiber and third single mode optical fiber successively at end.
Preferably, first single mode optical fiber, the second single mode optical fiber and third single mode optical fiber include fibre core and and packet
The covering being rolled in outside fibre core, a diameter of 8.2 μm of the fibre core, the overall diameter of fibre core and covering is 125 μm.
Preferably, the length of the described first thin core single mode optical fiber is 0.85cm.
Preferably, the described first thin core single mode optical fiber include fibre core and and the covering that is wrapped in outside fibre core, described the
125 μm of the overall diameter of one thin core single mode optical fiber, 3.6 μm of core diameter.
Preferably, the length of second single mode optical fiber is 6.45cm.
Preferably, the length of the described second thin core single mode optical fiber is 0.35cm.
Preferably, the described second thin core single mode optical fiber include fibre core and and the covering that is wrapped in outside fibre core, described the
125 μm of the overall diameter of two thin core single mode optical fibers, 4.4 μm of core diameter.
Preferably, the dislocation welding area between the front end and the rear end of the first single mode optical fiber of the described first thin core single mode optical fiber
The outer cover in domain is equipped with metal tube, is attached by PDMS between the metal tube and dislocation welding region.
Further, it is using the PDMS methods for being packaged reinforcing：Metal tube is removed into a part of side wall rear enclosure and is set to mistake
At the welding area of position, with PDMS host agents and curing agent with mass ratio 10：1 ratio after mixing, is made in the way of standing
Bubble in the mixed liquor of PDMS floating to surface and ruptures, and mixed liquor is injected metal tube later, is then positioned over 120 DEG C again
Cure 15 minutes on warm table.
Compared with prior art, the beneficial effects of the utility model：The utility model by analyze MZI operation principle,
Devise the core diameter and length of the composed structure and each section of optical fiber of MZI；Interference spectrum after design and optimization is obviously divided into
Three parts, the shortwave part of spectrum is essentially from the first thin-core fibers, and long wavelength part is essentially from the second single mode optical fiber, middle part
It is above-mentioned transition portion between the two to divide；The utility model is also between the single mode optical fiber of front end and thin-core fibers using dislocation
Welding, and PDMS encapsulation has been carried out to dislocation welding region and has been reinforced.The utility model is simple and strong in structure, and it is accurate to measure, sensitive
Degree is high, reproducible, can be sensed to quasi-continuous 2 ocean temperatures, and (range is about one li in a certain range
Rice is to 20 centimetres), 2 points of distance is flexibly adjustable.
Description of the drawings
Fig. 1 is the structural schematic diagram of the embodiments of the present invention 1；
Fig. 2 be in embodiment 1 FSR with SMF2 sections of length variation diagram；
Fig. 3 is spectrum comparison diagram in embodiment 1；
Fig. 4 is the sensor structure schematic diagram of comparative example 1；
Fig. 5 one section of 4.0cm Nufern 460-HP optical fiber of welding between two sections of general single mode fibers in comparative example 1
Transmitted spectrum；
Fig. 6 one section of 2.8cm Nufern780-HP optical fiber of welding between two sections of general single mode fibers in comparative example 1
Transmitted spectrum；
Fig. 7 is the sensor structure schematic diagram of comparative example 2；
Fig. 8 is the transmitted spectrum of comparative example 2；
Fig. 9 is the output spectrum 1 of different temperatures lower sensor structure in embodiment 2；
Figure 10 is the output spectrum 2 of different temperatures lower sensor structure in embodiment 2；
Figure 11 is the output spectrums of sensor II at different temperatures in embodiment 2；
Figure 12 is the output spectrum of tri- exemplary positions of B1, B2, B3 of sensor II in embodiment 2 at different temperatures.
Specific implementation mode
The utility model proposes a kind of all -fiber Mach-pool Deccan formed is cascaded by multistage single mode optical fiber thin-core fibers
Interferometer, for quasi-continuous 2 temperature sensing in seawater.By analyze MZI operation principle, devise MZI structure and each section
The core diameter and length of optical fiber, obtain clearly interference spectrum.By further optimizing, interference spectrum is obviously divided into three parts,
The fore-end of spectrum comes from the first thin-core fibers, and for decline essentially from the second single mode optical fiber, middle section is above-mentioned two
Transition portion between person.In addition, it is more secured in order to make the welding between two optical fiber splice, it introduces a kind of practical and simple
Reinforcement means.MZI based on making illustrates quasi-continuous 2 temperature sensing, has estimated sensitivity, and this sensor is surveyed
Magnitude is compared with thermometer measure value.
The laboratory apparatus of the utility model and consumptive material are as follows：
Super continuous laser source heat sealing machine
Spectrometer (AQ6370C)
Warm table
Dimethyl silicone polymer (PDMS)
8.2 microns of single mode optical fiber (SMF-28) core diameter, 125 microns of overall diameter
Thin-core fibers
(1) 2.5 microns of Nufern 460-HP core diameters, 125 microns of overall diameter
(2) 4.4 microns of Nufern 780-HP core diameters, 125 microns of overall diameter
(3) 3.6 microns of Nufern 980-HP core diameters, 125 microns of overall diameter
Utility model will be further described in detail below with reference to the attached drawings and specific embodiments.
1 sensor structure of embodiment designs
As shown in Figure 1, it is a kind of based on thin-core fibers and the cascade 2 ocean temperature sensors of standard single-mode fiber, including
The first single mode optical fiber (being named as SMF1), the first thin core single mode optical fiber (being named as TCF1) and the second single mode optical fiber being sequentially connected
Be welded together to the rear end dislocation of (being named as SMF2), the front end of TCF1 and SMF1, the rear end of TCF1 and the front end of SMF2 without
Dislocation it is welded together.Dislocation-free welding has the second thin core single mode optical fiber (being named as TCF2) and third successively for the rear end of SMF2
Single mode optical fiber (is named as SMF3).
Since misplaces fusion point is very fragile, the dislocation welding region between SMF1 and TCF1 needs (poly- with PDMS
Dimethyl siloxane) encapsulation.PDMS (polydimethylsiloxane), is the english abbreviation of dimethyl silicone polymer, is to have
One kind of machine silicon using simple, with having good adhesiveness between silicon chip, and has good chemistry because its is at low cost
The features such as inertia, becomes a kind of polymer material being widely used in micro-fluidic equal fields.PDMS packaged types are：By metal tube
A part of side wall rear enclosure is removed at dislocation welding region, with PDMS host agents and curing agent with mass ratio 10：The mixing of 1 ratio is equal
After even, the bubble in the mixed liquor of PDMS is made in the way of standing floating to surface and is ruptured, mixed liquor is injected into metal later
Pipe, is then positioned on 120 DEG C of warm table and cures 15 minutes again.
SMF1, SMF2 and SMF3 be including fibre core and and the standard single-mode fiber of covering that is wrapped in outside fibre core,
Its overall diameter is 125 μm, a diameter of 8.2 μm of fibre core.
The length of TCF1 is 0.85cm, TCF1 be include fibre core and and the thin core single mode of covering that is wrapped in outside fibre core
Optical fiber, TCF1 use the Nufern 980-HP that overall diameter is 3.6 μm for 125 μm, core diameter.TCF2 be include fibre core and with
And be wrapped in the thin core single mode optical fiber of the covering outside fibre core, TCF2 be overall diameter be 125 μm, core diameter is 4.4 μm
Nufern 780-HP。
SMF1-TCF1-SMF2-TCF2-SMF3 is sequentially connected by the present embodiment, and the sensing arrangement obtained can be applied to
Quasi-continuous 2 temperature in seawater measure.Its principle is as follows：
Light wave is propagated in inputting single mode optical fiber in the form of basic mode, and most light energies are strapped in fibre core.The 1st
At a fusion point (SMF1 and TCF1 intersections), due to the mismatch and dislocation welding of core diameter, part light injects the covering of TCF1,
To excite cladding mode to be transmitted in covering, effective refractive index is related with the refractive index of environmental liquids.Another part optical coupling
It into the fibre core of TCF1, is propagated in fibre core in the form of core mode, effective refractive index is not by the shadow of environmental liquids refractive index
It rings.Due to phase difference, cladding mode and core mode interfere.Which constitute first mode-interference units (to use IMI-A tables below
Show).
After by TCF1, two parts light will again couple in SMF2.However, at TCF1-SMF2 fusion points, TCF1
Covering in the part of cladding mode transmitted will be directed into the covering of SMF2 and propagated with cladding mode short distance, and
This cladding mode can be interfered with core mode, form second mode-interference unit (being indicated below with IMI-B).But
If SMF2 is long, cladding mode therein will degenerate, in order to keep the propagation of cladding mode in SMF2, the utility model
SMF2 is blocked to 6.45cm or so, then with the TCF2 of one section of very short 0.35cm (Nufern 780-HP) welding.Due to
TCF2 length is very short, and the Free Spectral Range that this section of optical fiber itself generates is very big, thus can be to avoid it to entire spectrum
Excessive modulation and interference.
Interference in order to further verify the parts IMI-B occurs mainly in the parts SMF2, and the utility model is based on following reason
By measure the SMF2 with different length transmitted spectrum (in addition to the length of the parts SMF2 is different, the structure group of other parts
Cheng Juntong Fig. 1), see Fig. 2.
Wherein Δ neffIt is the difference between core mode and covering Effective index, m is the order of interference of MZI, and L is to occur
The length of interference region, Δ λDip, mIt is wavelength interval (i.e. Free Spectral Range, the below letter between two adjacent interference minimum values
Claim FSR).
As shown in Fig. 2, with the increase of SMF2 length, FSR is gradually reduced.This experimental result and above-mentioned theory formula
(1) it is consistent, is certainly happened in SMF2 sections to demonstrate interference phenomenon.If in addition, figure it is seen that SMF2
Long (being probably more than 20cm), cladding mode therein will fail, in order to keep the propagation of cladding mode in SMF2, we
SMF2 is cut to 6.45cm, then with the TCF2 of a very short 0.35cm (Nufern780-HP) welding.Due to TCF2
Length is very short, and the Free Spectral Range of itself is very big, thus can be to avoid its excessive modulation and interference to entire spectrum.
Finally, it is connect with TCF2 with SMF3, is used as exporting with spectrometer connection signal, the transmitted light that spectrometer is collected
Spectrum is shown in Fig. 3.As shown in figure 3, the interference effect of first interferometer IMI-A mainly occupies leading position in short-wave band, second
The interference effect of interferometer IMI-B mainly occupies leading position in long-wave band, and in order to compare, the solid line in Fig. 3 is only at two
One section of length of dislocation welding is the transmitted light of the Nufern 980-HP thin-core fibers (TCF1) of 0.85cm among standard single-mode fiber
Spectrum, dotted line be plus after SMF2, TCF2 the utility model is related to entire MZI structures transmitted spectrum.As can be seen that in Fig. 3
Transmission spectrum in the i.e. interference information comprising IMI-A interference units also include the interference informations of IMI-B interference units, and two sets
It is relatively independent, a leading short wavelength regions, a leading Long wavelength region, so theoretically not to interfere the performance in spectrum
But it is suitble to while measures 2 points of ocean temperature, but also easily carry out spectrum analysis.
To sum up, structurally, contingency is not present for finished commercial prod in the thin-core fibers used in the utility model, and
PDMS packaging protections, stable structure has been used to be hardly damaged at dislocation welding.It is spectrally said from generating, includes two in output spectrum
Interference spectrum is covered, and this two sets of spectrum are relatively independent, a leading short wavelength regions to the modulation of entire spectrum, one leading
Long wavelength region so theoretically may be implemented to measure while 2 ocean temperatures, and can utilize Fourier analysis
Method easily analyzes spectrum, and the raising for follow-up sensing sensitivity provides reference.
Comparative example 1
As different from Example 1, by ordinary optic fibre welder by thin-core fibers both ends respectively with standard single mode light
Fine (SMF-28e) welding without acceptance of persons.Sensor structure as shown in Figure 4 is incident on using Supercontinuum source, with AQ6370C spectrum
Instrument (highest resolution is up to 20pm) measures the transmitted spectrum of sensor-based system.Liquid used is that salinity is in experimentation
33 ‰ sea water solution.
When the length of thin-core fibers Nufern 460-HP is 4.0cm, transmitted spectrum is shown in Fig. 5.It chooses in spectral line, wave
Paddy is characterized peak.As shown in figure 5, changing ocean temperature by warm table, it can be seen that with the increase of temperature, the curve of spectrum
Obviously moved to long wave length direction.Its temperature sensing sensitivity is 13pm/ DEG C.
When thin-core fibers select length be 2.8cm, the Nufern 780-HP that core diameter is 4 μm when, transmitted spectrum is shown in
Fig. 6.As shown in fig. 6, changing ocean temperature by warm table, it can be seen that with the increase of temperature, the curve of spectrum is obviously to length
Wavelength direction moves.Its temperature control is 32pm/ DEG C.
Comparison diagram 5 and Fig. 6, which can be seen that a FSR for the structure of welding Nufern 460-HP, will be far longer than a welding
The sensor of Nufern 780-HP structures, dynamic range is bigger, but sensitivity is relatively low.And only welding Nufern 780-HP
The sensor of structure, we are it is obvious that the interference extinction ratio of the spectrum is unfavorable for observing bright than shallower from Fig. 6
The observation that aobvious characteristic peak and subsequent peak move, and above two structure is only applicable to the ocean temperature measurement of single-point.
Comparative example 2
Unlike comparative example 1, in order to improve sensitivity, and the more obvious pattern of manufacture is dry penetrates effect, design such as Fig. 7
Shown in dislocation welding structure, in two section single-mould fibers, one segment length of dislocation welding be 0.85cm Nufern 980-HP it is thin
(before PDMS encapsulation) shown in solid in core fibre, obtained spectrum such as Fig. 8 (a).But because insecure at dislocation welding,
Dislocation join domain selects PDMS packaged types as described in Example 1 to carry out rock-steady structure, and the structure transmitted spectrum after encapsulation is such as
(Fig. 8 b are the thermometric spectrums for the structure for not meeting SMF2, TCF2 after independent dislocation welding TCF1) shown in dotted line in Fig. 8 (a).From Fig. 8
(b) increase with temperature is can be seen that, the curve of spectrum is obviously moved to long wave length direction, temperature control 46.3pm/
℃.As can be seen that it may be the folding due to PDMS that this encapsulation, which does not have the change for keeping spectral line too big, this slight change,
Penetrate rate (refractive index 1.406) differed with the refractive index (refractive index 1) of air it is larger caused by, it is also possible to be because envelope
PDMS is caused by the stress of optical fiber after dress solidification.But this approach sensor in comparative example 2, it is also only capable of for measuring list
Ocean temperature is put, the measurement for 2 ocean temperatures is simultaneously not suitable for.
To sum up, sensitivity is low, extinction ratio is low etc. may occur in single-point thermometric in the dislocation-free welding in comparative example 1
Problem, and the structure of the SMF-TCF-SMF in comparative example 2 is because only that a set of interference signal, therefore it is only applicable to single point temperature
It measures, is not suitable for use in quasi-continuous 2 ocean temperatures sensing.Even if two sensors in comparative example 2 are connected
(this part signal all concentrates on 1150nm to 1270nm to this partial coherence signal that two sensor extinction ratios can be caused relatively high
Wave band) it is directly superimposed in the same band and causes transmitted spectrum very chaotic, it is beyond recognition.
The measurement of 2 two temperature of embodiment
In order to demonstrate the utility model quasi-continuous 2 ocean temperatures sensing in application, the utility model carried out as
Lower experiment：The parts IMI-A shown in FIG. 1 are immersed in first sea container and are used as first temperature measuring point, IMI-B soaks part
Enter into second sea container and is used as second temperature measuring point；The 1cm that is spaced about of two containers (is considered quasi-continuous distribution
2 points)；Change the ocean temperature at two temperature measuring points respectively by warm table, and 2 seawater are carried out using thermocouple thermometer
Temperature measurement correction.
First, in the case where only changing first temperature measuring point temperature at IMI-A, we obtain transmission as shown in Figure 9
Spectrogram, and the peak for choosing two typical peaks Peak A, Peak B therein condition of shifting one's love is analyzed.As shown in figure 9, with temperature
Degree gradually increases, and above-mentioned two peak is deviated to long wave direction.Since the ocean temperature in this part Experiment at IMI-B is protected always
12.8 DEG C are held, so the variation of output spectrum is only caused by the temperature change of first temperature measuring point.By tracking A, B two
Peak, we have obtained the peak shifting amount at the two peaks and the relationship of temperature change, as shown in figure 9, slope is exactly corresponding sensitivity,
Respectively 42.7pm/ DEG C and 9.7pm/ DEG C.
Similarly, in the case where only changing second temperature measuring point temperature at IMI-B, the utility model is obtained such as Figure 10 institutes
The spectrogram shown, it can be seen that as temperature gradually increases, the two peaks also move right.Output spectrum is as shown in Figure 10, by
Ocean temperature in this part Experiment at first temperature measuring point of sample remains 14.3 DEG C, therefore the variation of output spectrum is only
Caused by the temperature change of IMI-B.Figure 10 shows that two kinds of peaks are moved with the raising of temperature to long wave direction.Pass through tracking
Two peaks above-mentioned A, B, obtain the relationship of their peak shifting amounts and temperature change, and as shown in Figure 10, slope is exactly corresponding sensitivity,
Respectively 8.4pm/ DEG C and 39.2pm/ DEG C.
To sum up, by embodiment 1 and embodiment 2 obtain based on cascade 2 seawater of thin-core fibers and standard single-mode fiber
Temperature sensor can measure the temperature change of 2 points of seawater.Although usually being recognized for being less than 15pm/ DEG C of sensitivity below
To be temperature-resistant, but it is stringent for the sake of, the utility model uses Temperature cross-over sensitivity of the following matrix to point-to-point transmission
It is corrected, i.e. two Typical interference peak peak A and peak B amount of movement Δs λA、ΔλBWith the temperature variation Δ T of two pointsA、ΔTB
Between there are following relationships：
The case where obtained above-mentioned matrix arbitrarily changes suitable for 2 temperature.In order to examine above-mentioned matrix, this practicality new
Type uses two test1 (T1), test2 (t2) samples to examine, and the test of sample t1, t2 and result of calculation are as shown in table 1.
The position at peak is substituted into above formula, test1 and test2 sample temperatures are calculated, the temperature of sample is measured by temperature in experiment
, test sample data are as shown in the table.The result shows that the ocean temperature measured by sensor using the utility model changes
Amount is consistent substantially with the knots modification that thermocouple measures, and shows that the measurement of the structure has good precision.
Table 1 carries out the test of sample test1, test2 using the sensor of the utility model
In above-described embodiment 2, since the length of sea container is 3.5cm, so the IMI-B partial-lengths heated are
3.5 centimetres, and the overall length of second interferometer IMI-B (SMF2) is 6.45cm, therefore we have made another similar knot
The sensor II (left end endless SMF1-0.85cmTCF1-6.3cmSMF2-0.4cmTCF2- right ends endless SMF3) of structure into
The experiment of the SMF2 length and sensing sensitivity relationship that are heated is gone, the structure of the sensor II is shown in Figure 12 (a).It is transmitted
Shown in spectrum such as 11 (a), we have selected different heated lengths as typical length, respectively 1.5cm, 3cm, 3.5cm and
5cm.The interference peak of 1548nm or so is chosen as typical peak (being indicated by the peaks B ').Correspondingly, it is drawn in Figure 11 (b) -11 (e)
Go out the case where peak B ' is varied with temperature, and the peak wavelength under different temperatures has been plotted in Figure 11 (f) -11 (i), it is sensitive
Degree is followed successively by 27.75pm/ DEG C, 38.29pm/ DEG C, 39.62pm/ DEG C, 47.5pm/ DEG C.In order to which further sensitivity for analysis is to length
Dependence, Figure 11 (j) depicts the relationship that sensitivity changes with heated length, in figure display with heated length increase,
Sensitivity can approximately linearly increase.And this is also consistent with the theoretical formula of following temperature controls：
According to (3) formula above, we can obtain, the position of second temperature measuring point does not influence sensitivity, as long as
Second temperature measuring point is located in the length range of SMF2.In order to verify this point, we have selected second temperature measuring point
Three different location (B in Figure 12 (a)1、B2And B3) it is used as three typical positions.Second interferometer IMI-B is immersed into sea
Water section length is fixed as 3.0cm.Same method depicts peak B in Figure 12 (b), 12 (c) and 12 (d)1、B2And B3With temperature
Degree variation the case where, by linear fit learn the corresponding sensitivity in three positions be respectively 39.41pm/ DEG C, 38.2pm/ DEG C and
37.10pm/ DEG C, this illustrates that temperature measuring point position is really unrelated with sensitivity, and in other words, the distances of two temperature measuring points can be
(it is usually no more than 20 centimetres) in the even greater ranges of 1cm to 6.45cm freely to adjust, does not all interfere with the thermometric of two points
Sensitivity has certain flexibility and novelty.
Although above having made detailed description to the utility model with generality explanation and specific embodiment,
On the basis of the utility model, it can be made some modifications or improvements, this is apparent to those skilled in the art
's.Therefore, these modifications or improvements on the basis of without departing from the spirit of the present invention, belong to the utility model and want
Seek the range of protection.
Claims (8)
1. one kind being based on thin-core fibers and the cascade 2 ocean temperature sensors of standard single-mode fiber, it is characterised in that：Including
The first single mode optical fiber, the first thin core single mode optical fiber and the second single mode optical fiber being sequentially connected, the first thin core single mode optical fiber
Front end and the rear end of the first single mode optical fiber are welded together with misplacing, rear end and the second single mode of the first thin core single mode optical fiber
The front end dislocation-free of optical fiber it is welded together；Dislocation-free welding has the second thin core list successively for the rear end of second single mode optical fiber
Mode fiber and third single mode optical fiber.
2. according to claim 1 be based on thin-core fibers and the cascade 2 ocean temperature sensors of standard single-mode fiber,
It is characterized in that：First single mode optical fiber, the second single mode optical fiber and third single mode optical fiber include fibre core and and are wrapped in
Covering outside fibre core, a diameter of 8.2 μm of the fibre core, the overall diameter of fibre core and covering is 125 μm.
3. according to claim 1 be based on thin-core fibers and the cascade 2 ocean temperature sensors of standard single-mode fiber,
It is characterized in that：The length of the first thin core single mode optical fiber is 0.85cm.
4. according to claim 3 be based on thin-core fibers and the cascade 2 ocean temperature sensors of standard single-mode fiber,
It is characterized in that：The first thin core single mode optical fiber include fibre core and and the covering that is wrapped in outside fibre core, described first is thin
125 μm of the overall diameter of core single mode optical fiber, 3.6 μm of core diameter.
5. according to claim 1 be based on thin-core fibers and the cascade 2 ocean temperature sensors of standard single-mode fiber,
It is characterized in that：The length of second single mode optical fiber is 6.45cm.
6. according to claim 1 be based on thin-core fibers and the cascade 2 ocean temperature sensors of standard single-mode fiber,
It is characterized in that：The length of the second thin core single mode optical fiber is 0.35cm.
7. according to claim 6 be based on thin-core fibers and the cascade 2 ocean temperature sensors of standard single-mode fiber,
It is characterized in that：The second thin core single mode optical fiber include fibre core and and the covering that is wrapped in outside fibre core, described second is thin
125 μm of the overall diameter of core single mode optical fiber, 4.4 μm of core diameter.
8. being based on thin-core fibers and cascade 2 ocean temperatures of standard single-mode fiber according to claim 1-7 any one of them
Sensor, it is characterised in that：Dislocation between the front end and the rear end of the first single mode optical fiber of the first thin core single mode optical fiber is molten
The outer cover for connecing region is equipped with metal tube, is attached by PDMS between the metal tube and dislocation welding region.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108168729A (en) * | 2018-01-30 | 2018-06-15 | 中国海洋大学 | Based on the cascade 2 ocean temperature sensors of thin-core fibers and standard single-mode fiber |
| CN108981956A (en) * | 2018-09-05 | 2018-12-11 | 东北大学 | Brass tube encapsulation type optical fiber temperature sensor |
-
2018
- 2018-01-30 CN CN201820164622.1U patent/CN207741874U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108168729A (en) * | 2018-01-30 | 2018-06-15 | 中国海洋大学 | Based on the cascade 2 ocean temperature sensors of thin-core fibers and standard single-mode fiber |
| CN108168729B (en) * | 2018-01-30 | 2024-02-13 | 中国海洋大学 | Two-point seawater temperature sensor based on cascade connection of fine core optical fiber and standard single mode optical fiber |
| CN108981956A (en) * | 2018-09-05 | 2018-12-11 | 东北大学 | Brass tube encapsulation type optical fiber temperature sensor |
| CN108981956B (en) * | 2018-09-05 | 2020-10-30 | 东北大学 | Brass Tube Encapsulated Fiber Optic SPR Temperature Sensor |
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