CN208238740U - The tapered optical fibre bending sensor of dual hump - Google Patents
The tapered optical fibre bending sensor of dual hump Download PDFInfo
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- CN208238740U CN208238740U CN201820443351.3U CN201820443351U CN208238740U CN 208238740 U CN208238740 U CN 208238740U CN 201820443351 U CN201820443351 U CN 201820443351U CN 208238740 U CN208238740 U CN 208238740U
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Abstract
The utility model relates to a kind of tapered optical fibre bending sensors of dual hump, especially can be to the fibre optical sensor of amount of curvature and bending direction while high-acruracy survey.The sensor is mainly made of the consistent optical fiber hump cone of two protrusion directions, which forms Mach-Zehnder (M-Z) interferometer.When the sensor bores protrusion direction by flecition along hump, the variation of axial unsymmetric structure is so that hump cone protrusion direction and refractive index backwards change, cause the core mode in Fiber-M-Z interferometer different from cladding mode transmission speed, the optical path difference of generation will cause the drift of interference peaks.The drift value size and drift bearing for measuring interference peaks, can be realized the high-precision of amount of curvature and bending direction while measuring.This dual hump type optical fibre bending sensor has many advantages, such as that dexterous structure, simple for production, function admirable, cost performance are high.
Description
Technical field
The utility model relates to a kind of fibre optical sensors, can carry out simultaneously high-precision sense to amount of curvature and bending direction
It surveys, belongs to technical field of optical fiber sensing.
Background introduction
Bending sensor is widely used to the numerous areas such as means of transportation, aviation and navigation, machine-building and Industry Control.
With the continuous development of measuring technique, nondirectional scalar flexural measurement device has been unable to meet engineering measurement demand, therefore each
The bending vector sensor that kind can recognize bending direction is increasingly taken seriously.Wherein, fibre optical sensor is because of its flexible shapes
Small and exquisite, electromagnetism interference, antioxidant anticorrosive and it is less by environmental restrictions the features such as, be widely used in the monitoring of all kinds of parameters.
The especially fibre optical sensor of phase modulation-type, as optical fiber mach-Zeng Deer (M-Z) interferometer is very suitable to Fiber bending sensing
Design, development and the application of device.
Hump wimble structure is a kind of asymmetric convex cone, and the optical fiber for removing coat by one section is transferred in certain prebuckling situation
Electricity is made, and discharge position deviates core centre, and the convex cone of production is spatially a unsymmetric structure.Research shows that:
Compact-sized, the sensitive bending sensor of sensing can be made using dual hump wimble structure, and then realize amount of curvature and bending
It is measured while direction.
The utility model is a kind of novel to amount of curvature and bending direction while can to carry out the optical fiber of high-precision sensing
Bending sensor.Search result shows still same to amount of curvature and bending direction without being made of dual hump wimble structure at present
When the patent report of optical fibre bending sensor that senses.
Summary of the invention
The purpose of this utility model, which is intended to design one kind, to amount of curvature and bending direction while to carry out high-precision sense
The optical fibre bending sensor of survey, the provided tapered optical fibre bending sensor of dual hump, including transducing part and measurement part.It passes
Sense part is made of the consistent asymmetric cone (hump cone) of two protrusion directions, as shown in Fig. 1 (a)；It is characterized in that utilizing electric arc
Discharge technology carries out prebuckling discharge treatment to optical fiber, forms the consistent hump cone of protrusion direction, in kind as shown in Fig. 1 (b).
Using sensor shown in FIG. 1, amount of curvature and bending direction can be measured simultaneously.Sensor measurement portion
The connection type being divided to: two tie points of sensing head (1), one is connect by transmission fiber (2) with light source (3), secondly passing through
Transmission fiber (2) connects with optical detector (4), as shown in Figure 2.Single mode optical fiber drawing technology is mature, and the country has been achieved with
Batch production, is easy to buy at present on the market.
In the present invention, prebuckling discharge treatment is carried out to optical fiber using arc-discharge technique, forms protrusion direction
Consistent hump cone, the fiber spiral structure of formation are Mach-Zehnder (M-Z) interferometer.When the sensor is convex along hump cone
When playing direction bending, the variation of axial unsymmetric structure is led so that hump cone protrusion direction and refractive index backwards change
It causes core mode in Fiber-M-Z interferometer different from cladding mode transmission speed, generates the drift that optical path difference will cause interference peaks.Measurement
The drift value size and drift bearing of interference peaks can be realized the high-precision to amount of curvature and bending direction while measuring.
Sensing head described in the utility model is that there are two the consistent hump wimble structures of protrusion direction for tool；The transmission light
Fibre is single mode optical fiber；The light source is wideband light source or tunable optical fiber laser；The optical detector be spectrometer or
Multi-wavelength meter；The working sensor environment temperature is between 0 DEG C~80 DEG C.
Sense principle:
The M-Z interferometer formed by dual hump wimble structure is a kind of dexterous, integrated full optical fiber interferometer, it is by reference light
It is concentrated in same section of optical fiber with signal light, the interference being typically based between different mode.It will be in all -fiber M-Z interferometer
Interference is reduced to two-beam interference between mode, then the two-beam for participating in interference is respectively as follows: fibre core basic mode and is bound among fibre core,
It is difficult to external world's perception, it can be used as reference light；The high-order cladding mode excited at hump cone (coupling unit) transmits in covering, right
External world's perception is sensitive, can be used as signal light.Then, the phase difference between two-beam can generally indicate are as follows:
In formula,Effective refractive index when not being bent for interferometer between fibre core basic mode and cladding mode is poor；L is interference length
Degree；λ is the wavelength of input light.The output intensity of the M-Z interferometer formed by dual hump wimble structure is represented by
In formula, I1And I2Respectively indicate the light intensity of fibre core basic mode Yu high-order cladding mode；δ is initial phase difference.It can by formula (2)
Know, whenWhen, light intensity reaches very big；WhenWhen, light intensity is then minimum.
When sensor is by flecition, the refractive index of fibre core and clad region can change, and one covering of fibre core is answered
Variation Δ ε=d/R, wherein d is the distance between fibre core and covering, and R is the bending radius of sensor.Then, effective refractive index
Difference is represented by
In formula, k is strain-specific refractivity.Formula (1)~formula (3) is the tapered optical fibre bending sensor sensing of dual hump
The expression formula of principle.When sensor bending, Δ neffIt is proportional to the curvature 1/R of optical fiber, this will lead to the drift of interference peaks.By
There is asymmetrical structure in hump cone, therefore the interference peaks drift that the flecition of different directions generates is different, utilizes
Measurement while this characteristic can realize amount of curvature and bending direction.
Measurement method:
After dual hump cone completes, the geometric parameter of the sensor is measured using optical fiber measurement instrument, is obtained simultaneously
Initial spectrum when interferometer is not bent is obtained, measuring device is as shown in Figure 2.Measurement method is as follows:
The first step, identification of the measurement sensor to bending direction.Firstly, the sensing head of sensor is placed in temperature control box,
A certain temperature-resistant (such as 20 DEG C) between 0 DEG C~80 DEG C are kept the temperature at, are recorded sensor initial spectrum (as shown in Figure 3)
And corresponding data；Then, apply 0 ° of direction (optical fiber is by the extruding from the direction+x in Fig. 1), 180 ° of directions respectively to sensing head
The flecition of (optical fiber is by the extruding from the direction-x in Fig. 1) successively records the drift situation at sensor interferometer peak；Finally,
The spectrum of record and data are handled, the corresponding relationship of sensor interferometer peak drift and bending direction is obtained.Measurement shows:
Sensor interferometer peak can delicately identify that, when being bent to 0 ° of direction, red shift occurs for interference peaks to bending direction；And to 180 °
When direction is bent, blue shift then occurs for interference peaks, and drift value and the curvature of interference peaks respond in a linear relationship.
Second step, measurement of the measurement sensor to bending parameters, by taking curvature as an example.Firstly, record sensor free state
Under interference spectrum and corresponding data, and be set to initial value, while recording environment temperature (such as 20 DEG C) and remaining unchanged；So
Afterwards, it is bent dual hump wimble structure, interference Frequency bias and corresponding data is recorded every certain curvature number scale, from small to large and replys survey
Amount；Finally, the interference spectrum repeatedly recorded and data are handled, sensor interferometer peak and curvature experimental relationship and fitting are obtained
Curve.
Third step changes environment temperature, takes certain certain value between 0 DEG C~80 DEG C and keep constant temperature, repeats the second pacing
Amount process is analyzed the measurement data of acquisition, is arranged, and the experiment of the interference peaks and curvature of different temperatures lower sensor is examined
Whether relationship is with uniformity, and whether sensitivity curve has linear character.
The utility model has the beneficial effects that
The utility model transducing part is optical fiber dual hump wimble structure, and structure is dexterous, simple for production, is easy to system collection
At, be also convenient for detected materials surface mount or be internally embedded.Utilize M-Z interferometer made of optical fiber dual hump wimble structure
Spectrum to flecition difference respond, by measure interference peaks drift value size and drift bearing, realize amount of curvature and
The high-precision of bending direction measures simultaneously.This novel sensor have measurement accuracy height, electromagnetism interference, easily design process,
Corrosion-resistant, suitable the features such as working in the presence of a harsh environment.
Detailed description of the invention
Fig. 1 is the sensing head of sensor.(a) sensing arrangement figure；(c) optical fiber dual hump bores pictorial diagram.
Fig. 2 is the utility model measuring device figure.In figure, 1. sensing heads；2. transmission fiber；3. light source；4. optical detector.
Fig. 3 is sensor interferometer spectrogram.
Fig. 4 is interference peaks drift of the sensor under 0 ° and 180 ° of two different directions bendings.
Fig. 5 is sensor when 0 °, 90 ° and 180 ° direction is bent, interference peaks λ=1580.01nm drift value and curvature
The matched curve of variation relation.
Specific embodiment
Using measuring device shown in Fig. 2, the sensing head of sensor is placed in temperature control box, maintains the temperature at 20 DEG C not
Become.Light is issued from light source, is received after sensing head by spectrometer.Light source used in measurement be wave-length coverage be 1250nm~
The wideband light source of 1650nm, model the Yokogawa AQ6370C, minimum resolution 0.02nm of spectrometer.Sensor
The center that intubating length is 10mm, internal diameter is 150 μm of capillaries, capillary both ends put on the copper post with clamping opening and are placed in two
On micro-displacement platform notch, wherein one end is fixed, and the counterweight that other end additional mass is 20g keeps optical fiber axial direction stress not
Become.Displacement platform is adjusted, the propulsion device transverse direction stepping with cylinder squeezes capillary and is allowed to be bent, drives in capillary and do
Same Bending Deformation occurs for interferometer.It adjusts optical fiber hump and bores convex direction, be bent respectively along 0 °, 90 °, 180 ° of directions, i.e.,
It can be achieved to measure while amount of curvature and bending direction
Measurement process
Before measurement, original state is set first, the spectrogram of sensor at this time, simultaneous selection allusion quotation are recorded using spectrometer
The interference peaks of type simultaneously measure its corresponding wavelength value；Then, using the initial value of sensor as reference value, sensor is applied not
Same curvature value 1/R simultaneously keeps the temperature-resistant of temperature control box, records the corresponding wavelength shift Δ λ of selected interference peakres；
Finally, by relational expression S=Δ λres/ (1/R) calculates the Bending Sensitivity of sensor.
Measurement sensing head used is bored using optical fiber hump made of arc-discharge technique, and transmission fiber is quartz single mode
Optical fiber, transmission wavelength are located at 1550nm wave band；Light source is wideband light source, and spectral region is 1250nm~1650nm；Optical detection
Device is fiber spectrometer, highest resolution 0.02nm；The operating ambient temperature of sensor is between 0 DEG C~80 DEG C.
Specific practical measuring examples
In the specific practical measuring examples of the utility model, sensing head parameter is as follows: optical fiber dual hump bores spacing L=13.4mm,
Hump cone cone waist maximum width is 155.4 μm, and cone section length is 360.8 μm, and single mode optical fiber is Corning SMF-28e.Work as biography
When sense head does not apply flecition, optical fiber dual hump is bored in the raw, and interference spectrum is as shown in figure 3, intetference-fit strengthening
More than 20dB, insertion loss is about 12dB.In flexural measurement, optical fiber is controlled using the lateral step size of cylinder propulsion device
Amount of curvature, every 0.1m-1Curvature value record interference Frequency bias and corresponding data, from small to large and reply measurement；It will be multiple
The interference spectrum and data of record are handled, and sensor interferometer peak and curvature experimental relationship and matched curve are obtained.
Fig. 4 is measurement result of the embodiments of the present invention under 0 ° and 180 ° of two different directions bendings, wherein to
When 0 ° of direction bending, red shift occurs for interference peaks；And when being bent to 180 ° of directions, blue shift then occurs for interference peaks.
Fig. 5 is the embodiments of the present invention when 0 °, 90 ° and 180 ° direction is bent, interference peaks λ=1580.01nm
The measurement result of drift value and Curvature varying.In 0~1.2m of curvature-1In range, linear fitting obtains the curved of 0 °, 180 ° direction
Bent sensitivity is respectively 10.224nm/m-1With -4.973nm/m-1.By Fig. 5 and further analysis shows that the utility model for
0 °, 180 ° of direction bending sensitivities, and 90 °, 270 ° of directions are bent then insensitive.
In addition, experimental study influence of the environment temperature to the sensor, transducing part is guaranteed by clamper and pulley
It is straight, it is placed in temperature control box, pulley quality is 20g.Temperature control box range of temperature is set as 0~80 DEG C, and when measurement becomes every time
To change 5 DEG C, is tested by the round-trip temperature of raising and lowering, the temperature sensitivity of interference peaks λ=1580.01nm is 0.049nm/ DEG C,
The right R of Linear Quasi2=0.994.In practical applications, it in order to cut down influence of the temperature to flexural measurement result, can use curved
The bent two-parameter matrix constituted with temperature, effectively solves the problems, such as the cross sensitivity of bending parameters and temperature.
Further, electric signal is converted optical signals to by photoelectric converter, then carries out data processing with computer, then may be used
Further increase the bending sensing sensitivity of the utility model.
Claims (6)
1. a kind of tapered optical fibre bending sensor of dual hump, including transducing part and measurement part, transducing part are protruded by two
The consistent hump cone in direction is constituted, it is characterized in that carrying out prebuckling discharge treatment to optical fiber using arc-discharge technique, is formed convex
The consistent asymmetric wimble structure in direction out constitutes Mach-Zenhder (M-Z) interferometer, realizes to amount of curvature and bending
The high-precision in direction measures simultaneously；The connection type of sensor measurement part: two tie points of sensing head (1), one pass through
Transmission fiber (2) is connect with light source (3), secondly being connected by transmission fiber (2) with optical detector (4).
2. the tapered optical fibre bending sensor of dual hump according to claim 1, it is characterized in that the sensing in the sensor
Head is the consistent hump cone of two protrusion directions；The optical fiber that the cone production of optical fiber hump uses can be various types of optical fiber, optical fiber
Type include standard single-mode fiber, doubly clad optical fiber, polarization maintaining optical fibre, multimode fibre, hollow optic fibre, photonic crystal fiber or micro-
Structured optical fiber.
3. the tapered optical fibre bending sensor of dual hump according to claim 1, it is characterized in that the transmission fiber is single
Mode fiber.
4. the tapered optical fibre bending sensor of dual hump according to claim 1, it is characterized in that the light source is broadband light
Source or tunable optical fiber laser.
5. the tapered optical fibre bending sensor of dual hump according to claim 1, it is characterized in that the optical detector is light
Spectrometer or Multi-wavelength meter.
6. the tapered optical fibre bending sensor of dual hump according to claim 1, it is characterized in that the working sensor ring
Border temperature is between 0 DEG C~80 DEG C.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201820443351.3U CN208238740U (en) | 2018-03-30 | 2018-03-30 | The tapered optical fibre bending sensor of dual hump |
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| CN201820443351.3U CN208238740U (en) | 2018-03-30 | 2018-03-30 | The tapered optical fibre bending sensor of dual hump |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110786857A (en) * | 2019-10-15 | 2020-02-14 | 天津大学 | Wearable optical fiber breathing tidal volume detection device |
| CN111399109A (en) * | 2019-07-10 | 2020-07-10 | 南开大学 | Long-period fiber grating based on inclined arc modulation structure |
| CN112648930A (en) * | 2020-12-15 | 2021-04-13 | 东北电力大学 | Light intensity modulation type optical fiber voltage sensor |
-
2018
- 2018-03-30 CN CN201820443351.3U patent/CN208238740U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111399109A (en) * | 2019-07-10 | 2020-07-10 | 南开大学 | Long-period fiber grating based on inclined arc modulation structure |
| CN110786857A (en) * | 2019-10-15 | 2020-02-14 | 天津大学 | Wearable optical fiber breathing tidal volume detection device |
| CN112648930A (en) * | 2020-12-15 | 2021-04-13 | 东北电力大学 | Light intensity modulation type optical fiber voltage sensor |
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Granted publication date: 20181214 Termination date: 20210330 |