Intrinsical Fabry-Perot strain gauge and its manufacture based on Modulation Based on Optical Fiber Fused Taper
Method
Technical field
The present invention relates to a kind of fibre optical sensor, especially a kind of optical fiber stress sensor is applied to optical fibre device technology
Field.
Background technique
In recent years, optical fiber stress sensor is widely used in the safety of the great building such as dam, tunnel, Longspan Bridge
In health detection, meanwhile, reliable safety detection is carried out with very big difficulty to such great building.It is built as to large size
Build safety measurement important parameter, high-sensitivity measurement is always a difficult point of optical fibre device production field, it is main because
Element is: optical fiber stress sensor has that manufacture craft is complex, size is larger, at high cost, optical fiber sensitivity is more low asks
Topic.Therefore, the optical fiber stress sensor based on Mach-Zender interferometer and based on photonic crystal fiber is with respect to manufacture craft
Simply, size is small, at low cost, high sensitivity.
There are optical fiber sensitivity to be difficult to improve, temperature drift is big etc. asks based on the strain transducer of fiber bragg grating for tradition
Topic;Strain transducer based on Mach-Zender interferometer, which generally requires, uses optical fiber dislocation welding and loop detection system,
Processing is difficult to control;Strain transducer higher cost based on photonic crystal fiber.As full optical fiber interference type sensor, optical fiber
Intrinsical Fabry-Perot device sensors are that measurement is realized based on simple optical fiber two-beam interference.When external environment such as temperature
When the factors such as degree, refractive index, stress, strain and magnetic field change, the phase of light beam changes.Compared to other kinds of light
Fiber sensor part, optical fiber Intrinsical Fabry-Perot device is detected with high resolution, easily, multiplexing capacity is strong, anti-interference ability
The advantages that strong.With the emergence and development of femtosecond laser technology, the advantage of ultrashort laser pulse and high peak intensities makes it micro-
Manufacture field is widely used.When femtosecond laser beam focuses on progress micro Process on fiber core, can precisely it control
Working position processed and region, and machining area very little can optimize optical fiber Intrinsical Fabry-Perot device sensors significantly
Performance.Meanwhile Modulation Based on Optical Fiber Fused Taper is as a kind of important foundation optical fibre device, it is carefully straight with special tapered transmission line structure and cone waist
Characteristic, when cone waist diameter is sufficiently small, stress sensing sensitivity will be obviously improved.But sensitivity, resolution ratio and response speed are also
It needs to be further improved, it is extensive that the reliability by further increasing preparation process can just be such that optical fiber stress sensor has
Application prospect.
Summary of the invention
In order to solve prior art problem, it is an object of the present invention to overcome the deficiencies of the prior art, and to provide one kind
Intrinsical Fabry-Perot strain gauge and its manufacturing method based on Modulation Based on Optical Fiber Fused Taper, combine Modulation Based on Optical Fiber Fused Taper device and light
The advantages of both fiber fabry-perot devices, the stress sensing for significantly improving optical fiber Intrinsical Fabry-Perot device are sensitive
Degree, high-resolution and fast-response speed are realized the stress sensing measurement for the advantage of having more, are widely applied to realize.
In order to achieve the above objectives, the present invention adopts the following technical scheme:
A kind of Intrinsical Fabry-Perot strain gauge based on Modulation Based on Optical Fiber Fused Taper, Modulation Based on Optical Fiber Fused Taper pass through heating melting mark
Quasi-fiber is drawn, and mainly includes three parts: thin straight cone lumbar region domain, symmetrical transitional region, fiber area, using flying
Second laser, inscribes two symmetrical refraction index changing regions in the middle part of the cone lumbar region domain of Modulation Based on Optical Fiber Fused Taper, forms optical fiber Intrinsical method
Two reflecting mirrors of Fabry-Perot-type tension sensor, as reflecting surface.Present invention incorporates the thin right cone waist of Modulation Based on Optical Fiber Fused Taper spies
Property, the reflectance spectrum wave crest under not pulling force effect using fiber Fabry-Pérot cavity easily monitors characteristic and resonance peak deviates easily inspection
Characteristic is surveyed, sensing sensitivity, reliability and the application range of fiber optic sensing device are further improved.
As currently preferred technical solution, femtosecond laser, the optical fiber for being 50-125 μm in cone waist diameter range are utilized
Reflecting mirror is inscribed on the cone lumbar region domain of pyrometric cone, the distance range between two on fiber core internal mirror is set as 100-
600μm。
As currently preferred technical solution, the Intrinsical Fabry-Perot stress based on Modulation Based on Optical Fiber Fused Taper is utilized
The pull sensing characteristic of sensor measurement environmental change parameter, the sensor measurement is related to cone waist diameter, by changing light
Fine pyrometric cone bores waist diameter, to obtain the sensing sensitivity to different measurement environmental change parameters.
A kind of manufacturing method of the Intrinsical Fabry-Perot strain gauge based on Modulation Based on Optical Fiber Fused Taper, includes the following steps:
1) Modulation Based on Optical Fiber Fused Taper preparation process:
Before being drawn to optical fiber, interception setting length optical fiber, in a fiber between peel off length be not more than 2cm painting
Coating, and with dehydrated alcohol wiped clean, as prestretching optical fiber;Then prestretching optical fiber is placed in fiber clamp, makes to peel off
The optical fiber of coat is in the centre of fiber clamp, and one section of general single mode parallel with prestretching optical fiber is placed in the fixture of both sides
Optical fiber, to fix prestretching optical fiber;Then by process control tensile speed, tensile elongation and hydrogen flowing quantity parameter, by adding
Heat fusing draws to obtain Modulation Based on Optical Fiber Fused Taper, obtains the optical fiber welding with thin straight cone lumbar region domain, symmetrical transitional region, fiber area
Cone;
2) process flow of fiber Fabry-Pérot cavity is inscribed using femtosecond laser:
The Modulation Based on Optical Fiber Fused Taper prepared by the Modulation Based on Optical Fiber Fused Taper preparation process is fixed on glass slide, and glass slide is placed
On three-dimensional micro Process platform;
Then the focusing objective len for being not less than 50 multiplying powers is chosen, is monitored by CCD and determines femtosecond laser focus position, is moved
Dynamic micro Process platform, focuses on fiber core for femtosecond laser;
Then using top-down longitudinal processing method, i.e. the moving direction of optical fiber is parallel to the biography of femtosecond laser beam
Defeated direction;When being laser machined again, femtosecond laser is focused on into fiber core, allow micro Process platform first along the z-axis direction to
Upper movement, laser focus on the lower section of fibre core, and electronic shutter is moved down and clicked then along z-axis direction, makes femtosecond laser
Across fibre core, to form internal mirror on fibre core, first reflecting mirror is inscribed;
Then the distance for moving setting to the cone waist other end along x-axis, continues to inscribe second reflecting mirror;
To utilize femtosecond laser, two symmetrical refraction index changing areas are inscribed in the middle part of the cone lumbar region domain of Modulation Based on Optical Fiber Fused Taper
Domain forms two reflecting mirrors of optical fiber Intrinsical Fabry-Perot tension sensor, as reflecting surface.
When preparing Modulation Based on Optical Fiber Fused Taper using Modulation Based on Optical Fiber Fused Taper preparation process, the tensile elongation of preferably made Modulation Based on Optical Fiber Fused Taper selection
Not less than 6000 μm, preferably cone waist diameter is not higher than 125 μm.Further preferably cone waist diameter is not higher than 60 μm.
In the process flow for inscribing fiber Fabry-Pérot cavity using femtosecond laser, the light of femtosecond laser inscription is utilized
The chamber of fiber fabry-perot chamber is preferably 100~1000 μm long.
As currently preferred technical solution, in the technique stream for inscribing fiber Fabry-Pérot cavity using femtosecond laser
Cheng Zhong is inscribed when inscribing to optical fiber using the recording power of 20mW, the distance that micro Process platform moves up and down point
Wei not be 20 μm and 14 μm, the speed that platform moves up and down is 1 μm/s.When single mode optical fiber is inscribed, make refraction index changing area
Domain can preferably cover the uniform and stable distribution of fibre core and obtain higher intetference-fit strengthening.
The present invention compared with prior art, has following obvious prominent substantive distinguishing features and remarkable advantage:
1. the advantages of present invention incorporates both Modulation Based on Optical Fiber Fused Taper devices and optical fibre Fabry-perot device is, it can be achieved that Gao Ling
The stress sensing of sensitivity, high-resolution and fast-response speed measures;
2. the stress sensitivity of Modulation Based on Optical Fiber Fused Taper Intrinsical Fabry-Perot strain gauge of the present invention is at least traditional list
4~5 times of mode fiber Intrinsical Fabry-Perot strain gauge;Because of the thin right cone waist structure of Modulation Based on Optical Fiber Fused Taper, work as Modulation Based on Optical Fiber Fused Taper
When the cone waist diameter of Fabry-Perot-type cavity is less than 60 μm, stress sensitivity even can reach traditional single mode optical fiber Fabry-
5 times or more of Perot sensor;
3. the present invention senses the thin right cone waist characteristic and optical fiber Intrinsical Fabry-Perot high-resolution of Modulation Based on Optical Fiber Fused Taper special
Property combine, not only increase sensing sensitivity, resolution ratio, response speed and the reliability of fiber optic sensing device and have wide
General application prospect.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of Intrinsical Fabry-Perot device of the embodiment of the present invention one based on Modulation Based on Optical Fiber Fused Taper.
Fig. 2 is that a length of 200 μm of two lumen of the embodiment of the present invention of optical fiber Intrinsical Fabry-Perot-type cavity becomes with extraneous stress
The reflectance spectrum situation map of change.
Fig. 3 is that a length of 400 μm of two lumen of the embodiment of the present invention of optical fiber Intrinsical Fabry-Perot-type cavity becomes with extraneous stress
The reflectance spectrum situation map of change.
Fig. 4 is that two lumen of the embodiment of the present invention is 200 μm a length of, 400 μm, 600 μm of optical fiber Intrinsical Fabry-Perot device
Part reflectance spectrum is with stress variation situation map.
Fig. 5 is that the Intrinsical method that waist diameter is 61 μm and a length of 200 μm of the Modulation Based on Optical Fiber Fused Taper of chamber is bored in the embodiment of the present invention three
The reflectance spectrum situation map that Fabry-Perot-type device changes with extraneous stress.
Fig. 6 is that the Intrinsical method that waist diameter is 61 μm and a length of 400 μm of the Modulation Based on Optical Fiber Fused Taper of chamber is bored in the embodiment of the present invention three
The reflectance spectrum situation map that Fabry-Perot-type device changes with extraneous stress.
Fig. 7 is that four Modulation Based on Optical Fiber Fused Taper of embodiment of the present invention cone waist diameter is 125 μm, 97 μm, 73 μm, 59 μm, 50 μm, and chamber is a length of
The feelings that reflection spectrum wavelength changes with extraneous stress are normalized in the Intrinsical Fabry-Perot device of 200 μm of Modulation Based on Optical Fiber Fused Taper
Condition figure.
Specific embodiment
Above scheme is described further below in conjunction with specific implementation example, the preferred embodiment of the present invention is described in detail such as
Under:
Embodiment one
In the present embodiment, referring to Fig. 1, a kind of Intrinsical Fabry-Perot strain gauge based on Modulation Based on Optical Fiber Fused Taper
Manufacturing method includes the following steps:
1) Modulation Based on Optical Fiber Fused Taper preparation process:
Before being drawn to optical fiber, interception setting length optical fiber, in a fiber between peel off length be not more than 2cm painting
Coating, and with dehydrated alcohol wiped clean, as prestretching optical fiber;Then prestretching optical fiber is placed in fiber clamp, makes to peel off
The optical fiber of coat is in the centre of fiber clamp, and one section of general single mode parallel with prestretching optical fiber is placed in the fixture of both sides
Optical fiber, to fix prestretching optical fiber;Then by process control tensile speed, tensile elongation and hydrogen flowing quantity parameter, by adding
Heat fusing draws to obtain Modulation Based on Optical Fiber Fused Taper, obtains the light with thin straight cone lumbar region domain 1, symmetrical transitional region 2, fiber area 3
Fine pyrometric cone;
2) process flow of fiber Fabry-Pérot cavity is inscribed using femtosecond laser:
The Modulation Based on Optical Fiber Fused Taper prepared by the Modulation Based on Optical Fiber Fused Taper preparation process is fixed on glass slide, and glass slide is placed
On three-dimensional micro Process platform;
Then the focusing objective len for being not less than 50 multiplying powers is chosen, is monitored by CCD and determines femtosecond laser focus position, is moved
Dynamic micro Process platform, focuses on fiber core for femtosecond laser;
Then using top-down longitudinal processing method, i.e. the moving direction of optical fiber is parallel to the biography of femtosecond laser beam
Defeated direction;When being laser machined again, femtosecond laser is focused on into fiber core, allow micro Process platform first along the z-axis direction to
Upper movement, laser focus on the lower section of fibre core, and electronic shutter is moved down and clicked then along z-axis direction, makes femtosecond laser
Across fibre core, to form internal mirror on fibre core, first reflecting mirror is inscribed;
Then the distance for moving setting to the cone waist other end along x-axis, continues to inscribe second reflecting mirror;
To utilize femtosecond laser, two symmetrical refraction index changing areas are inscribed in the middle part of the cone lumbar region domain 1 of Modulation Based on Optical Fiber Fused Taper
Domain forms two reflecting mirrors of optical fiber Intrinsical Fabry-Perot tension sensor, as reflecting surface 4.
The present embodiment carries out in the process flow for inscribing fiber Fabry-Pérot cavity using femtosecond laser to optical fiber
It when inscription, is inscribed using the recording power of 20mW, the distance that micro Process platform moves up and down is respectively 20 μm and 14 μm, is put down
The speed that platform moves up and down is 1 μm/s.When single mode optical fiber is inscribed, refraction index changing region is enable preferably to cover fibre
The uniform and stable distribution of core simultaneously obtains higher intetference-fit strengthening.
Referring to Fig. 1, the Intrinsical Fabry-Perot stress sensing device manufactured in the present embodiment based on Modulation Based on Optical Fiber Fused Taper leads to
It crosses flame fused biconical taper technology and draws out the Modulation Based on Optical Fiber Fused Taper that cone waist diameter is 50-125 μm or so, and with femtosecond laser in optical fiber
It inscribes two reflecting mirrors and forms Intrinsical Fabry-Perot stress sensing device, the chamber of senser element in the cone lumbar region domain of pyrometric cone
A length of 100~1000 μm.
The present embodiment is prepared for the Intrinsical Fabry-Perot strain gauge based on Modulation Based on Optical Fiber Fused Taper, and Modulation Based on Optical Fiber Fused Taper passes through
Heating melting standard fiber is drawn, and mainly includes three parts: thin straight cone lumbar region domain 1, symmetrical transitional region 2, light
Two symmetrical refraction index changing regions, shape are inscribed in the middle part of the cone lumbar region domain 1 of Modulation Based on Optical Fiber Fused Taper using femtosecond laser in fine region 3
At two reflecting mirrors of optical fiber Intrinsical Fabry-Perot tension sensor, as reflecting surface 4.It is manufactured in the present embodiment in light
The Intrinsical Fabry-Perot strain gauge of fine pyrometric cone combines the thin right cone waist characteristic of Modulation Based on Optical Fiber Fused Taper, in not pulling force effect
The lower reflectance spectrum wave crest using fiber Fabry-Pérot cavity easily monitors characteristic and resonance peak offset easily detection characteristic, further mentions
The high sensing sensitivity of fiber optic sensing device, reliability and application range.Tension sensor characteristic and cone under the device
Waist diameter is related.
Embodiment two
The present embodiment is basically the same as the first embodiment, and is particular in that:
In the present embodiment, referring to figs. 2 and 3, Intrinsical Fabry-Perot strain gauge based on Modulation Based on Optical Fiber Fused Taper
Manufacturing method prepares the single mode optical fiber Intrinsical Fabry-Perot strain gauge that long chamber is respectively 200 μm and 400 μm, then
It measures, stress changes to 1N from 0N, acquires a data every 0.1N, obtains the situation of change of reflectance spectrum.With sensing
The increase of device both ends stress, reflectance spectrum is whole to drift about to long wave length direction.Intrinsical Fabry-Perot based on Modulation Based on Optical Fiber Fused Taper
The manufacturing method of strain gauge prepares the single mode optical fiber Intrinsical Fabry-Perot stress sensing that long chamber is respectively 600 μm
Device is chosen the valley near 1551nm and is monitored, and wavelength is as shown in Figure 4 with the change curve of sensor both ends stress.Reflection
There is good linear relationship between spectrum wavelength variation and the variable quantity of stress.By calculating us it can be concluded that, the chamber of sensor
When a length of 200 μm, 400 μm and 600 μm, stress sensitivity is respectively as follows: 1.322nm/N, 1.336nm/N and 1.382nm/N.
Embodiment three
The present embodiment is substantially the same as in the previous example, and is particular in that:
In the present embodiment, referring to figs. 5 and 6, Intrinsical Fabry-Perot strain gauge based on Modulation Based on Optical Fiber Fused Taper
Manufacturing method, preparation cone waist diameter is 61 μm, and long chamber is respectively the Intrinsical Fabry-Perot of 200 μm and 400 μm of Modulation Based on Optical Fiber Fused Taper
Sieve device monitors the case where trough wavelength near 1565nm and 1574nm is with stress variation.When the diameter of optical fiber reduces, identical
In the case where extraneous stress, the drift value of Modulation Based on Optical Fiber Fused Taper Intrinsical Fabry-Perot strain gauge reflectance spectrum compares conventional single-mode
Optical fiber Intrinsical Fabry-Perot strain gauge is more.By calculating us it can be concluded that, when the interference wave of sensor is a length of
At 200 μm and 400 μm, stress sensitivity is respectively 6.669nm/N and 5.984nm/N.
Example IV
The present embodiment is substantially the same as in the previous example, and is particular in that:
In the present embodiment, referring to Fig. 7, the manufacture of the Intrinsical Fabry-Perot strain gauge based on Modulation Based on Optical Fiber Fused Taper
Method, being prepared for Modulation Based on Optical Fiber Fused Taper cone waist diameter is 125 μm, 97 μm, 73 μm, 59 μm and 50 μm, a length of 200 μm of the Modulation Based on Optical Fiber Fused Taper of chamber
The case where Intrinsical Fabry-Perot strain gauge carries out sensing experiment, and normalization reflection spectrum wavelength changes with extraneous stress
As shown in Figure 7.In the case where identical interference cavity length, with the cone waist of Modulation Based on Optical Fiber Fused Taper Intrinsical Fabry-Perot strain gauge
The reduction of diameter, wave length shift are gradually increased with extraneous stress slope of a curve, and incrementss also increase with the reduction of radius.
By the comparison of the two, the stress sensitivity of Modulation Based on Optical Fiber Fused Taper Intrinsical Fabry-Perot strain gauge is at least conventional single-mode
4~5 times of optical fiber Intrinsical Fabry-Perot strain gauge, because of the thin right cone waist structure of Modulation Based on Optical Fiber Fused Taper, when the present embodiment light
When the cone waist diameter of fine pyrometric cone Fabry-Perot-type cavity is less than 60 μm, stress sensitivity even can reach traditional single mode optical fiber
5 times or more of Fabry-Pérot sensor.
In conclusion the Intrinsical Fabry-Perot device based on Modulation Based on Optical Fiber Fused Taper of the above embodiment of the present invention preparation is drawn
Force snesor is inscribed two refraction index changing regions inside the cone waist of Modulation Based on Optical Fiber Fused Taper by femtosecond pulse laser and forms reflection
Mirror surface obtains different pull sensing sensitivity by changing Modulation Based on Optical Fiber Fused Taper cone waist diameter.When senser element is drawn by the external world
When power, small change can all occur for chamber length, core diameter and the fiber core refractive index of Modulation Based on Optical Fiber Fused Taper Intrinsical Fabry-Pérot sensor
Change, so that the optical path difference of optical fiber Intrinsical Fabry-Pérot sensor changes, drift motion occurs so as to cause reflectance spectrum and sees
Examine external tensile force variation.This device is by the thin right cone waist characteristic of Modulation Based on Optical Fiber Fused Taper and optical fiber Intrinsical Fabry-Perot high-resolution
Sensing characteristics combine, not only increase sensing sensitivity, resolution ratio, response speed and the reliability of fiber optic sensing device and
It is with a wide range of applications.
Combination attached drawing of the embodiment of the present invention is illustrated above, but the present invention is not limited to the above embodiments, it can be with
The purpose of innovation and creation according to the present invention makes a variety of variations, under the Spirit Essence and principle of all technical solutions according to the present invention
Change, modification, substitution, combination or the simplification made, should be equivalent substitute mode, as long as meeting goal of the invention of the invention,
Without departing from the present invention is based on the technology of the Intrinsical Fabry-Perot strain gauge of Modulation Based on Optical Fiber Fused Taper and its manufacturing method originals
Reason and inventive concept, belong to protection scope of the present invention.