CN206291958U - Optical fiber acoustic detection system - Google Patents
Optical fiber acoustic detection system Download PDFInfo
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- CN206291958U CN206291958U CN201621257791.7U CN201621257791U CN206291958U CN 206291958 U CN206291958 U CN 206291958U CN 201621257791 U CN201621257791 U CN 201621257791U CN 206291958 U CN206291958 U CN 206291958U
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Abstract
The utility model provides a kind of optical fiber acoustic detection system, belongs to technical field of optical fiber sensing.The system is including power output device, the first distributed sensing device based on backward Rayleigh scattering principle, based on the second distributed sensing device of backward weak optical fiber Bragg grating principle of reflection and the 3rd distributed sensing device, the first distributed sensing device is connected with power output device respectively with the second distributed sensing device, and the first distributed sensing device is connected with the 3rd distributed sensing device respectively with the second distributed sensing device.Relative to prior art, the scheme being combined with each other using backward weak optical fiber Bragg grating reflected signal in backward Rayleigh scattering signal in the first distributed sensing device and the second distributed sensing device, signal contrast and the sensitivity of detection system are greatly improved, the detective bandwidth of detection system has significantly been widened by the 3rd distributed sensing device.
Description
Technical field
The utility model is related to technical field of optical fiber sensing, in particular to a kind of optical fiber acoustic detection system.
Background technology
Optical fiber distributed type sonic detection technology is the optical fiber sound field reduction technique of current forefront, it using tested sound wave as
The function of fiber lengths, can continuously be surveyed on whole fiber lengths to the information of acoustic wave along fiber geometries path profile
Amount, for industry and research field provide the spatial distribution state of the tested physical parameter of acquisition simultaneously and change over time information
Means, obtain in fields such as Intelligent flight device, smart bridge, highway, Important building, gas piping monitoring and fiber optic cable monitors
Obtained and be widely applied.
Current optical fiber distributed type sound wave sensing technology includes the quasi-distributed sensing technology of fiber grating and optical time domain reflection skill
Art.The quasi-distributed sensing technology of fiber grating realizes the distributed monitoring to sound wave using the reflex of fiber grating, and
Mainly use the wavelength variation information of fiber grating, but the capacity and reusability of traditional concatenation type fiber grating are low.Light time
Domain reflection technology mainly uses optical fiber effect such as Rayleigh, Brillouin of generation under acoustic perturbation effect to measure, but dissipates
Signal energy after penetrating is very weak so that the technical indicator such as detecting distance, spatial resolution is relatively low.
Utility model content
The purpose of this utility model is to provide a kind of optical fiber acoustic detection system, to be effectively improved above mentioned problem.
To achieve these goals, the technical solution adopted in the utility model is as follows：
In a first aspect, the utility model embodiment provides a kind of optical fiber acoustic detection system, it includes that power output is filled
Put, the first distributed sensing device based on backward Rayleigh scattering principle, based on backward weak optical fiber Bragg grating principle of reflection second
Distributed sensing device and the 3rd distributed sensing device, the first distributed sensing device and second distributed sensing
Device is connected with the power output device respectively, the first distributed sensing device and the second distributed sensing device
Connected with the 3rd distributed sensing device respectively, the pulse signal exported by the power output device is by described first
Distributed sensing device part returns to form backward Rayleigh scattering signal and by the first distributed sensing device output, part
By forming the first direct impulse signal, the pulse signal exported by the power output device is passed by the described second distribution
Induction device part returns to form backward weak optical fiber Bragg grating reflected signal and be led to by the second distributed sensing device output, part
The second direct impulse signal of formation is crossed, the first direct impulse signal and the second direct impulse signal are by the described 3rd
Distributed sensing device forms the 3rd detectable signal, and the 3rd detectable signal is exported by the 3rd distributed sensing device.
In the utility model preferred embodiment, the power output device includes laser, acousto-optic modulator, first
Image intensifer, the first optical filter and the first coupler, the first distributed sensing device and second distributed sensing
Device respectively with the first coupler optical coupling, the optical signal exported by the laser sequentially passes through the acousto-optic modulator
With first image intensifer, exported respectively to the first distributed sensing device and described by first coupler
Two distributed sensing devices.
In the utility model preferred embodiment, the first distributed sensing device includes the first detection optical fiber, the
One circulator, the second image intensifer and the first photodetector, the pulse signal exported by the power output device is by institute
First annular device is stated into first detection optical fiber and is partly returned and formed the backward Rayleigh scattering signal, partly pass through shape
Into the first direct impulse signal, the backward Rayleigh scattering signal sequentially passes through the first annular device and second light
Amplifier, is received and is exported by first photodetector, the first direct impulse signal output to the described 3rd distribution
Formula sensing device.
In the utility model preferred embodiment, the second distributed sensing device includes the second detection optical fiber, the
Second ring device, the second optical filter and the second photodetector, the pulse signal exported by the power output device is by institute
The second circulator is stated into second detection optical fiber and part return forms the backward weak optical fiber Bragg grating reflected signal, part
By forming the second direct impulse signal, the backward weak optical fiber Bragg grating reflected signal sequentially passes through second circulator
With second optical filter, received and exported by second photodetector, the second direct impulse signal output is extremely
The 3rd distributed sensing device.
In the utility model preferred embodiment, the 3rd distributed sensing device includes the second coupler, the 3rd
Optical filter, the 3rd circulator, fiber optic interferometric device and Electro-Optical Sensor Set, the first distributed sensing device and described
Two distributed sensing devices respectively with the second coupler optical coupling, as the first distributed sensing device export described in
First direct impulse signal and the second direct impulse signal for being exported by the second distributed sensing device are by described
Second coupler sequentially passes through second optical filter, the 3rd circulator, is returned into the fiber optic interferometric device part
It is back-shaped into the 3rd detectable signal, the 3rd detectable signal is received and exported by the Electro-Optical Sensor Set.
In the utility model preferred embodiment, the fiber optic interferometric device includes 3 × 3 couplers, the first faraday
Revolving mirror and the second faraday rotation mirror, the Electro-Optical Sensor Set include the 3rd photodetector, the 4th photodetector and
5th photodetector, by the first direct impulse signal and the second direct impulse signal of the 3rd circulator
Into 3 × 3 coupler, partly reflected back into through first faraday rotation mirror by 3 × 3 coupler output described
In 3 × 3 couplers, partly 3 × 3 coupling is reflected back into through second faraday rotation mirror by 3 × 3 coupler output
In clutch, the 3rd detectable signal is formed in 3 × 3 coupler, the 3rd detectable signal is through described 3 × 3 couplings
Device is exported, and is partly received and is exported by the 3rd photodetector by the 3rd circulator, partly by the 4th light
Electric explorer is received and exported, and is partly received and is exported by the 5th photodetector.
In the utility model preferred embodiment, the fiber optic interferometric device includes 2 × 2 couplers, the 3rd faraday
Revolving mirror, the 4th faraday rotation mirror and phase-modulator, the Electro-Optical Sensor Set include the 6th photodetector, by institute
The the first direct impulse signal and the second direct impulse signal for stating the 3rd circulator enter 2 × 2 coupler, portion
Divide and reflected back into 2 × 2 coupler through the 3rd faraday rotation mirror by 2 × 2 coupler output, partly by institute
The output of 2 × 2 couplers is stated to be reflected by the 4th faraday rotation mirror through the phase-modulator, then through the phase-modulator
Return in 2 × 2 coupler, the 3rd detectable signal, the 3rd detectable signal are formed in 2 × 2 coupler
Exported through 2 × 2 coupler, received and exported by the 6th photodetector.
In the utility model preferred embodiment, first detection optical fiber is single-mode fiber.
In the utility model preferred embodiment, second detection optical fiber is comprising at least one weak optical fiber Bragg grating
Single-mode fiber.
Second aspect, the utility model embodiment additionally provides a kind of optical fiber acoustic detection system, and it includes power output
Device, the first distributed sensing device, the second distributed sensing device, the 3rd distributed sensing device and fiber-optic signal demodulation system
System, the first distributed sensing device is connected with the power output device respectively with the second distributed sensing device,
The first distributed sensing device connects with the 3rd distributed sensing device respectively with the second distributed sensing device
Connect, the first distributed sensing device, the second distributed sensing device and the 3rd distributed sensing device difference
Connected with the fiber-optic signal demodulating system, the pulse signal exported by the power output device is distributed by described first
Sensing device part returns to form backward Rayleigh scattering signal and be exported to the optical fiber by the first distributed sensing device
Signal demodulating system, partly by forming the first direct impulse signal, the pulse signal exported by the power output device is passed through
The second distributed sensing device part is crossed to return to form backward weak optical fiber Bragg grating reflected signal and by the described second distribution
Sensing device exports to the fiber-optic signal demodulating system, partly passes through to form the second direct impulse signal, and described first is positive
Pulse signal and the second direct impulse signal form the 3rd detectable signal by the 3rd distributed sensing device, described
3rd detectable signal is exported to the fiber-optic signal demodulating system by the 3rd distributed sensing device.
The optical fiber acoustic detection system that the utility model embodiment is provided, is obtained by the first distributed sensing device and carried
The backward Rayleigh scattering signal of sound wave positional information is backward Rayleigh scattering signal in detected space, by the second distributed sensing
Device obtains the intensity signal of ad-hoc location and the backward dim light grid reflected signal of acoustic wave phase information in carrying detected space
Backward weak optical fiber Bragg grating reflected signal, then the backward Rayleigh scattering signal and backward weak fiber that fiber-optic signal demodulating system is obtained
Optical grating reflection signal greatly improves the signal contrast of whole optical fiber acoustic detection system using the scheme of normalization demodulation
And sensitivity.Simultaneously by the 3rd distributed sensing device, by from the first direct impulse of the first distributed sensing device outgoing
Signal and the second direct impulse signal from the second distributed sensing device outgoing use passive phase demodulating scheme, significantly widen
The detective bandwidth of system.The capacity of the optical fiber acoustic detection system provided relative to prior art, the utility model embodiment
And reusability is high, and the technical indicator such as detecting distance, spatial resolution is high, its Cleaning Principle without time-division multiplex technology, not
Quantity required for considerably reducing original single acoustic phase sensor on the premise of increasing sensor fibre length, reduces
The technical difficulty that the complexity and system of system are realized, substantially reduces system cost.
Brief description of the drawings
In order to illustrate more clearly of the technical scheme of the utility model embodiment, below will be to be used needed for embodiment
Accompanying drawing be briefly described, it will be appreciated that the following drawings illustrate only some embodiments of the present utility model, therefore should not be by
Regard the restriction to scope as, for those of ordinary skill in the art, on the premise of not paying creative work, may be used also
Other related accompanying drawings are obtained with according to these accompanying drawings.
Fig. 1 provides the schematic diagram of optical fiber acoustic detection system for the utility model embodiment；
The schematic diagram of the optical fiber acoustic detection system that Fig. 2 is provided for the utility model first embodiment；
The schematic diagram of the power output device that Fig. 3 is provided for the utility model first embodiment；
The schematic diagram of the first distributed sensing device that Fig. 4 is provided for the utility model first embodiment；
The schematic diagram of the second distributed sensing device that Fig. 5 is provided for the utility model first embodiment；
The schematic diagram of the 3rd distributed sensing device that Fig. 6 is provided for the utility model first embodiment；
The schematic diagram of the optical fiber acoustic detection system that Fig. 7 is provided for the utility model second embodiment；
The schematic diagram of the optical fiber acoustic detection system that Fig. 8 is provided for the utility model 3rd embodiment.
Icon：100- the first distributed sensing devices；200- the second distributed sensing devices；The distributed sensings of 300- the 3rd
Device；400- power output devices；500- fiber-optic signal demodulating systems；1000- optical fiber acoustic detection systems.
Specific embodiment
It is new below in conjunction with this practicality to make the purpose, technical scheme and advantage of the utility model embodiment clearer
Accompanying drawing in type embodiment, is clearly and completely described, it is clear that retouched to the technical scheme in the utility model embodiment
The embodiment stated is a part of embodiment of the utility model, rather than whole embodiments.Generally described in accompanying drawing herein and
The component of the utility model embodiment for showing can be arranged and designed with a variety of configurations.
Therefore, the detailed description of embodiment of the present utility model below to providing in the accompanying drawings is not intended to limit requirement
The scope of the present utility model of protection, but it is merely representative of selected embodiment of the present utility model.Based in the utility model
Embodiment, the every other embodiment that those of ordinary skill in the art are obtained under the premise of creative work is not made, all
Belong to the scope of the utility model protection.
It should be noted that：Similar label and letter represents similar terms in following accompanying drawing, therefore, once a certain Xiang Yi
It is defined in individual accompanying drawing, then it need not be further defined and explained in subsequent accompanying drawing.
It is term " in ", " on ", D score, "left", "right", " perpendicular, it is necessary to explanation in description of the present utility model
Directly ", the orientation or position relationship of the instruction such as " level ", " interior ", " outward " be based on orientation shown in the drawings or position relationship, or
It is the orientation or position relationship usually put when the utility model product is used, is for only for ease of description the utility model and letter
Change description, rather than indicate imply signified device or element must have specific orientation, with specific azimuth configuration and
Operation, therefore it is not intended that to limitation of the present utility model.Additionally, term " first ", " second ", " the 3rd " etc. are only used for area
Divide description, and it is not intended that indicating or implying relative importance.
Additionally, the term such as term " level ", " vertical ", " pendency " is not offered as requiring part abswolute level or pendency, and
Can be to be slightly tilted.It is not the expression structure if " level " refers to only its direction with respect to more level for " vertical "
Must be fully horizontal, and can be to be slightly tilted.
In description of the present utility model, in addition it is also necessary to explanation, unless otherwise clearly defined and limited, term " sets
Put ", " installation ", " connected ", " connection " should be interpreted broadly, for example, it may be fixedly connected, or be detachably connected,
Or be integrally connected；Can mechanically connect, or electrically connect；Can be joined directly together, it is also possible to by intermediary
It is indirectly connected to, can is two connections of element internal.For the ordinary skill in the art, can be managed with concrete condition
Solve concrete meaning of the above-mentioned term in the utility model.
Additionally, the term such as " output ", " process ", " passing through ", " return ", " formation " be understood as describing a kind of optics,
Electricity changes or optics, electricity treatment.As " passing through " refer to only optical signal or electric signal by the equipment, instrument or device it
Change optically or electrically is there occurs afterwards so that the optical signal or the electric signal are processed, and then are implemented
Signal required for technical scheme or solution technical problem.
In specific embodiment of the utility model accompanying drawing, for more preferable, clearer description optical fiber acoustic detection system
The operation principle of system interior each equipment, instrument and device, the current logic for showing optical signal and electric signal in the system, it is simply bright
It is aobvious to have distinguished each equipment, the relative position relation between instrument and device, can not constitute to light path, circuit direction and equipment instrument
Device size, size, the restriction of shape.
Fig. 1 is refer to, the utility model embodiment provides a kind of optical fiber acoustic detection system 1000, and it includes the first distribution
Formula sensing device 100, the second distributed sensing device 200, the 3rd distributed sensing device 300 and power output device 400, institute
The first distributed sensing device 100 is stated to be connected with power output device 400 respectively with the second distributed sensing device 200, it is described
First distributed sensing device 100 also connects with the 3rd distributed sensing device 300 respectively with the second distributed sensing device 200
Connect.
The pulse signal exported by the power output device 400 enters by the first distributed sensing device 100
A part for the pulse signal of the first distributed sensing device 100 is returned to form backward auspicious by the first distributed sensing device 100
Sharp scattered signal, and exported by the first distributed sensing device 100；Another part is positive to pass through the first distributed sensing device
100 form the first direct impulse signal.The pulse signal exported by the power output device 400 is distributed by described second
Sensing device 200, into the second distributed sensing device 200 pulse signal a part by the second distributed sensing device
200 returns form backward weak optical fiber Bragg grating reflected signal, and are exported by the second distributed sensing device 200；Another part is positive
Second direct impulse signal is formed by the second distributed sensing device 200.The first direct impulse signal and described second
Direct impulse signal enters in the 3rd distributed sensing device 300, and the is formed by the treatment of the 3rd distributed sensing device 300
Three detectable signals, and the 3rd detectable signal exports by the 3rd distributed sensing device 300.
In the present embodiment, the backward Rayleigh scattering signal can be carried in detected space after sound wave positional information
To Rayleigh scattering signal, the backward weak optical fiber Bragg grating reflected signal can be the light intensity letter for carrying ad-hoc location in detected space
The backward dim light grid reflected signal of breath and acoustic wave phase information.The backward Rayleigh scattering signal and the backward weak optical fiber Bragg grating
Reflected signal can be exported to photoelectric detector or fiber-optic signal demodulating system, use the scheme that normalization is demodulated to obtain quilt
Survey the position of sound wave and phase information in space.The first direct impulse signal and the second direct impulse signal are the 3rd
Interfered in distributed sensing device 300, the 3rd detectable signal for carrying interference signal is exported to photodetector
Part or optical signal demodulation system, and can obtain sound field environment in detected space by using corresponding passive phase demodulating scheme
Information.
First embodiment
Fig. 2 is refer to, the present embodiment provides a kind of optical fiber acoustic detection system 1000, it includes that the first distributed sensing is filled
Put the 100, second distributed sensing device 200, the 3rd distributed sensing device 300 and power output device 400, described first point
Cloth sensing device 100 is connected with power output device 400 respectively with the second distributed sensing device 200, first distribution
Formula sensing device 100 is connected with the 3rd distributed sensing device 300 respectively with the second distributed sensing device 200.
Fig. 3 is refer to, the power output device 400 includes laser, acousto-optic modulator, the first image intensifer, first
Optical filter and the first coupler, the first distributed sensing device and the second distributed sensing device respectively with it is described
First coupler optical coupling.In the present embodiment, the laser can be distributed feedback (Distributed
Feedback, DFB) optical fiber laser (hereinafter referred to as DFB optical fiber lasers), by DFB optical fiber lasers export it is continuous just
The direct impulse signal with certain pulsewidth and cycle is modulated into by the acousto-optic modulator to incident optical signal, then is passed through
First image intensifer amplifies, and is exported respectively to the first distributed sensing device and described by first coupler
Second distributed sensing device.
Fig. 4 is refer to, the first distributed sensing device 100 includes the first detection optical fiber, first annular device, the second light
Amplifier and the first photodetector, the forward entrance light pulse signal exported by the DFB optical fiber lasers is by described the
One coupler enters the A1 ends of the first annular device, and is brought out from A2 and inject in first detection optical fiber.In this implementation
In example, first detection optical fiber can be general single mode fiber, can not be eliminated because optical signal can be produced in single-mode fiber
Rayleigh scattering, which part carry detected space in sound wave positional information backward Rayleigh scattering signal from described first detection
The A2 ends of the first annular device are returned in optical fiber, and is exported from the A3 ends of the first annular device, then put by the second light
Big device is received and exported by first photodetector.First is being formed from the part of first detection optical fiber forward direction outgoing just
To pulse signal, into the 3rd distributed sensing device 300.
It is to be understood that, the circulator in the present embodiment is a kind of multiport device, and signal therethrough is only
Can be transmitted in the form of unidirectional loop.The signal being for example input into from the A1 ends of the first annular device, can only be from this annular
The A2 ends output of device；And the signal being input into from the A2 ends of this circulator, can only be exported from the A3 ends of this circulator.To be carried with this
Different information and the different Signal separator in direction is opened.
Fig. 5 is refer to, the second distributed sensing device 200 includes the second detection optical fiber, the second circulator, the second light
Wave filter and the second photodetector, the forward entrance light pulse signal exported by the DFB optical fiber lasers is by described the
One coupler enters the B1 ends of second circulator, and is brought out from B2 and inject in second detection optical fiber.In this implementation
In example, second detection optical fiber can be the single-mode fiber comprising at least one weak optical fiber Bragg grating, the reflection of its fiber grating
Rate is preferably less than 10%, due to it is every by a grating will reflecting part optical signal, by the light of the weak optical fiber Bragg grating
Signal carries the intensity signal at the sensor fibre in detected space between ad-hoc location i.e. each fiber grating, wherein by light
The part optical signals of fine optical grating reflection return to the B2 ends of second circulator, and defeated from the B3 ends of second circulator
Go out, then received and exported by second photodetector by the second optical filter.Go out from the second detection optical fiber forward direction
The part penetrated forms the second direct impulse signal, into the 3rd distributed sensing device 300.In the present embodiment, second
The spacing of each fiber grating can accomplish very little in detection optical fiber, and measurement is sensor fibre between each fiber grating
The intensity signal at place, so as to improve the spatial resolution of detection system.
Fig. 6 is refer to, the 3rd distributed sensing device 300 includes the second coupler, the 3rd optical filter, the 3rd ring
Shape device, 3 × 3 couplers, the first faraday rotation mirror, the second faraday rotation mirror, the 3rd photodetector, the 4th photodetection
Device and the 5th photodetector.The first direct impulse signal and the second direct impulse signal are coupled by described second
Device is coupled as forward entrance optical signal all the way, is input into from the C1 ends of the 3rd circulator by the 3rd optical filter, and
Exported to the P1 ends of 3 × 3 coupler from C2 ends.Into a part of optical signals P4 ends of 3 × 3 coupler export to
First faraday rotation mirror, and the P4 ends of 3 × 3 coupler are reflected back into by first faraday rotation mirror；One
Part optical signals are exported to second faraday rotation mirror by P5 ends, and reflect back into institute by second faraday rotation mirror
State the P5 ends of 3 × 3 couplers；Also small part optical signal is exported to its exterior from P6 ends, can be made in a particular embodiment
P6 end seals are lived with reflection device or light receiving device part.By first faraday rotation mirror and second faraday rotation mirror
Optical signal after modulated is interfered in 3 × 3 coupler, and forms acoustic wave phase information in carrying detected space
Optical signal.Exported to the C2 of the 3rd circulator by the P1 ends of 3 × 3 couplers by the optical signal part after interference
End, is exported, then received and exported by the 3rd photodetector by C3 ends；A part is exported by the P2 ends of 3 × 3 couplers,
Directly received and exported by the 4th photodetector；A part is exported by the P3 ends of 3 × 3 couplers, directly by described the
Five photodetectors are received and exported.
In the present embodiment, 3 × 3 coupler, the first faraday rotation mirror and the common structure of the second faraday rotation mirror
Into a Michelson's interferometer, realize that to entering the forward entrance optical signal in the device be to institute as fiber optic interferometric device
State the interference of the first direct impulse signal and the second direct impulse signal；And the 3rd photodetector, the 4th photoelectricity
Detector and the 5th photodetector are then received as Electro-Optical Sensor Set to be distinguished by P1, P2 and P3 end of 3 × 3 coupler
The optical signal of output.The P4 ends of 3 × 3 coupler to first faraday rotation mirror distance, and 3 × 3 couplers
To the second faraday rotation mirror distance, it is the integral multiple of System spatial resolution apart from its difference S at P5 ends.
First image intensifer and second image intensifer in the present embodiment can be that pulsed erbium doped fiber amplifies
Device, the output signal of the DFB optical fiber lasers can be the near infrared light that wavelength is 1550nm.The optical fiber acoustic detection system
System 1000 in each equipment, can be that signal transmission is carried out by optical fiber between instrument or device.By the described first smooth electrical resistivity survey
Survey the electric signal of device, the second photodetector, the 3rd photodetector, the 4th photodetector and the 5th photodetector output
Can accordingly be demodulated in input system external equipment such as fiber-optic signal demodulating system, to obtain position, the frequency of sound wave
And phase information, you can complete the complete detection to the information of acoustic wave of ad-hoc location in detected space.
Second embodiment
Fig. 7 is refer to, the present embodiment provides a kind of optical fiber acoustic detection system 1000, it includes that the first distributed sensing is filled
Put the 100, second distributed sensing device 200, the 3rd distributed sensing device 300 and power output device 400.It is new with this practicality
The maximum difference of type first embodiment is that the 3rd circulator is eliminated in the 3rd distributed sensing device 300, and
3 × 3 coupler, the first faraday rotation mirror and the second faraday rotation mirror are replaced with into 2 × 2 couplers, the 3rd respectively
Faraday rotation mirror and the 4th faraday rotation mirror, and add between the 4th faraday rotation mirror in 2 × 2 coupler
Enter a phase-modulator, the 3rd photodetector, the 4th photodetector and the 5th photodetector are replaced with into the 6th light
Electric explorer.
The first direct impulse signal and the second direct impulse signal are coupled as one by second coupler
Road forward entrance optical signal, is input into by the 3rd optical filter from the P1 ends of 2 × 2 coupler.Into described 2 × 2
A part of optical signals P3 ends of coupler are exported to the 3rd faraday rotation mirror, and by the 3rd faraday rotation mirror
Reflect back into the P3 ends of 2 × 2 coupler；A part of optical signals P4 ends output, institute is incident to through the phase-modulator
The 4th faraday rotation mirror is stated, and the P4 ends of 2 × 2 coupler are reflected back into by the 4th faraday rotation mirror.By
3rd faraday rotation mirror, the phase-modulator and the 4th faraday rotation mirror it is modulated after optical signal in institute
State and interfered in 2 × 2 couplers, and form the optical signal for carrying acoustic wave phase information in detected space.By after interference
Optical signal is exported by the P2 ends of 2 × 2 couplers, then is received and exported by the 6th photodetector.
In the present embodiment, 2 × 2 coupler, the 3rd faraday rotation mirror, phase-modulator and the 4th faraday rotation
Tilting mirror collectively forms a Michelson's interferometer, is realized to entering the forward entrance light in the device as fiber optic interferometric device
Signal is the interference to the first direct impulse signal and the second direct impulse signal.And the 6th photodetector
The optical signal exported by the P4 ends of 2 × 2 coupler is then received as Electro-Optical Sensor Set.The P3 ends of 2 × 2 coupler
To the distance of the 3rd faraday rotation mirror, and 2 × 2 couplers P4 ends to the 4th faraday rotation mirror distance, its
It is the integral multiple of System spatial resolution apart from its difference S.
In the present embodiment, the electric signal exported by the 6th photodetector can input system external equipment such as optical fiber
Phase carrier demodulation is carried out in signal demodulating system, you can the phase information of sound wave in detected space is obtained, relative to this practicality
New first embodiment, the 3rd distributed sensing device 300 with 2 × 2 couplers as core used in the present embodiment also can
Same function is enough completed, and system architecture is more simple.
3rd embodiment
Fig. 8 is refer to, the present embodiment provides a kind of optical fiber acoustic detection system 1000, it includes that the first distributed sensing is filled
Put the 100, second distributed sensing device 200, the 3rd distributed sensing device 300, power output device 400 and fiber-optic signal solution
Adjusting system 500, the first distributed sensing device 100 and the second distributed sensing device 200 are respectively and power output device
400 connections, the first distributed sensing device 100 and the second distributed sensing device 200 respectively with the 3rd distributed sensing
Device 300 is connected, the first distributed sensing device 100, the second distributed sensing device 200 and the 3rd distributed sensing dress
300 are put to be connected with the fiber-optic signal demodulating system 500 respectively.It is maximum with the utility model first embodiment and second embodiment
Difference be, by the first distributed sensing device 100, the second distributed sensing device 200 and described 3rd point
Each detectable signal of information of acoustic wave is finally transfused to the fiber-optic signal in the carrying detected space of the output of cloth sensing device 300
In demodulating system 500.
The backward Rayleigh scattering signal exported by the first distributed sensing device 100 enters the fiber-optic signal demodulating system
In 500, after carrying out the relevant treatments such as differential superposition, you can obtain the position signalling of tested sound wave.Filled by the second distributed sensing
The backward weak optical fiber Bragg grating reflected signal for putting 200 outputs enters in the fiber-optic signal demodulating system 500, can be by detected space
The intensity signal of ad-hoc location demodulates the acoustic phase at the sensor fibre in the second detection optical fiber between each fiber grating
Information.The 3rd detectable signal exported by the 3rd distributed sensing device 300 enters in the fiber-optic signal demodulating system 500,
The difference of the internal components according to the 3rd distributed sensing device 300, carries out 3 × 3 passive phase demodulatings or phase carrier demodulation,
The frequency and phase information of sound wave can be demodulated without complicated time division multiplex system.
In sum, the optical fiber acoustic detection system that the utility model embodiment is provided, is filled by the first distributed sensing
The i.e. backward Rayleigh scattering signal of backward Rayleigh scattering signal for obtaining and carrying sound wave positional information in detected space is put, by second
Distributed sensing device obtains the intensity signal and the backward dim light grid of acoustic wave phase information for carrying ad-hoc location in detected space
Reflected signal is backward weak optical fiber Bragg grating reflected signal, then by fiber-optic signal demodulating system obtain backward Rayleigh scattering signal and
Backward weak optical fiber Bragg grating reflected signal greatly improves whole optical fiber acoustic detection system using the scheme of normalization demodulation
Signal contrast and sensitivity.Simultaneously by the 3rd distributed sensing device, by from the of the first distributed sensing device outgoing
One direct impulse signal and the second direct impulse signal from the second distributed sensing device outgoing use passive phase demodulating side
Case, has significantly widened the detective bandwidth of system.Relative to the optical fiber acoustic detection that prior art, the utility model embodiment are provided
The capacity and reusability of system are high, and the technical indicator such as detecting distance, spatial resolution is high, and its Cleaning Principle is without time division multiplex
Technology, the number required for original single acoustic phase sensor is considerably reduced on the premise of not increasing sensor fibre length
Amount, reduces the technical difficulty that the complexity and system of system are realized, substantially reduces system cost.The foregoing is only this practicality
New preferred embodiment, is not limited to the utility model, and for a person skilled in the art, this practicality is new
Type can have various modifications and variations.It is all within spirit of the present utility model and principle, any modification for being made, equally replace
Change, improve, should be included within protection domain of the present utility model.
Claims (10)
1. a kind of optical fiber acoustic detection system, it is characterised in that including power output device, based on backward Rayleigh scattering principle
It is first distributed sensing device, distributed based on the second distributed sensing device of backward weak optical fiber Bragg grating principle of reflection and the 3rd
Sensing device, the first distributed sensing device and the second distributed sensing device respectively with the power output device
Connection, the first distributed sensing device is filled with the 3rd distributed sensing respectively with the second distributed sensing device
Connection is put, the pulse signal exported by the power output device is returned by the first distributed sensing device part and formed
Backward Rayleigh scattering signal is simultaneously exported by the first distributed sensing device, partly passes through to form the first direct impulse signal,
The pulse signal exported by the power output device is returned by the second distributed sensing device part and forms backward weak
Fiber Bragg grating reflected signal is simultaneously exported by the second distributed sensing device, partly passes through to form the second direct impulse signal,
The first direct impulse signal and the second direct impulse signal form the 3rd by the 3rd distributed sensing device
Detectable signal, the 3rd detectable signal is exported by the 3rd distributed sensing device.
2. optical fiber acoustic detection system according to claim 1, it is characterised in that the power output device includes laser
Device, acousto-optic modulator, the first image intensifer, the first optical filter and the first coupler, the first distributed sensing device with
The second distributed sensing device respectively with the first coupler optical coupling, the optical signal exported by the laser is successively
By the acousto-optic modulator and first image intensifer, exported respectively to the described first distribution by first coupler
Formula sensing device and the second distributed sensing device.
3. optical fiber acoustic detection system according to claim 1, it is characterised in that the first distributed sensing device bag
The first detection optical fiber, first annular device, the second image intensifer and the first photodetector are included, is exported by the power output device
Pulse signal by the first annular device into first detection optical fiber and part return formed the backward Rayleigh dissipate
Penetrate signal, partly by forming the first direct impulse signal, the backward Rayleigh scattering signal sequentially passes through described first
Circulator and second image intensifer, are received and are exported by first photodetector, the first direct impulse signal
Export to the 3rd distributed sensing device.
4. optical fiber acoustic detection system according to claim 1, it is characterised in that the second distributed sensing device bag
The second detection optical fiber, the second circulator, the second optical filter and the second photodetector are included, is exported by the power output device
Pulse signal by second circulator into second detection optical fiber and part return form the backward weak fiber
Optical grating reflection signal, partly by forming the second direct impulse signal, the backward weak optical fiber Bragg grating reflected signal is successively
By second circulator and second optical filter, received and exported by second photodetector, described second
Direct impulse signal output is to the 3rd distributed sensing device.
5. optical fiber acoustic detection system according to claim 1, it is characterised in that the 3rd distributed sensing device bag
Include the second coupler, the 3rd optical filter, the 3rd circulator, fiber optic interferometric device and Electro-Optical Sensor Set, first distribution
Formula sensing device and the second distributed sensing device respectively with the second coupler optical coupling, it is distributed by described first
The first direct impulse signal of sensing device output and by the second distributed sensing device export described second just
The 3rd optical filter, the 3rd circulator are sequentially passed through by second coupler to pulse signal, into described
Fiber optic interferometric device part returns to form the 3rd detectable signal, and the 3rd detectable signal is connect by the Electro-Optical Sensor Set
Receive and export.
6. optical fiber acoustic detection system according to claim 5, it is characterised in that the fiber optic interferometric device includes 3 × 3
Coupler, the first faraday rotation mirror and the second faraday rotation mirror, the Electro-Optical Sensor Set include the 3rd photodetector,
4th photodetector and the 5th photodetector, by the first direct impulse signal of the 3rd circulator and described
Second direct impulse signal enters 3 × 3 coupler, is partly revolved through first faraday by 3 × 3 coupler output
Tilting mirror is reflected back into 3 × 3 coupler, partly exports anti-through second faraday rotation mirror by 3 × 3 coupler
It is emitted back towards in 3 × 3 coupler, the 3rd detectable signal, the 3rd detection letter is formed in 3 × 3 coupler
Number through 3 × 3 coupler export, partly received and exported by the 3rd photodetector by the 3rd circulator,
Part is received and is exported by the 4th photodetector, is partly received and is exported by the 5th photodetector.
7. optical fiber acoustic detection system according to claim 5, it is characterised in that the fiber optic interferometric device includes 2 × 2
Coupler, the 3rd faraday rotation mirror, the 4th faraday rotation mirror and phase-modulator, the Electro-Optical Sensor Set include the 6th
Photodetector, enters by the first direct impulse signal of the 3rd circulator and the second direct impulse signal
2 × 2 coupler, partly reflects back into described 2 × 2 by 2 × 2 coupler output through the 3rd faraday rotation mirror
In coupler, partly reflected by the 4th faraday rotation mirror through the phase-modulator by 2 × 2 coupler output,
Returned in 2 × 2 coupler through the phase-modulator again, the 3rd detection letter is formed in 2 × 2 coupler
Number, the 3rd detectable signal is exported through 2 × 2 coupler, is received and is exported by the 6th photodetector.
8. optical fiber acoustic detection system according to claim 3, it is characterised in that first detection optical fiber is single-mode optics
It is fine.
9. optical fiber acoustic detection system according to claim 4, it is characterised in that second detection optical fiber is comprising extremely
A few single-mode fiber for weak optical fiber Bragg grating.
10. a kind of optical fiber acoustic detection system, it is characterised in that including power output device, the first distributed sensing device,
Two distributed sensing devices, the 3rd distributed sensing device and fiber-optic signal demodulating system, the first distributed sensing device
It is connected with the power output device respectively with the second distributed sensing device, the first distributed sensing device and institute
The second distributed sensing device is stated to be connected with the 3rd distributed sensing device respectively, the first distributed sensing device,
The second distributed sensing device and the 3rd distributed sensing device are connected with the fiber-optic signal demodulating system respectively,
The pulse signal exported by the power output device is returned by the first distributed sensing device part and forms backward auspicious
Sharp scattered signal and exported to the fiber-optic signal demodulating system by the first distributed sensing device, partly by forming the
One direct impulse signal, the pulse signal exported by the power output device is by the second distributed sensing device part
Return forms backward weak optical fiber Bragg grating reflected signal and is exported to the fiber-optic signal solution by the second distributed sensing device
Adjusting system, partly by forming the second direct impulse signal, the first direct impulse signal and second direct impulse are believed
Number the 3rd detectable signal is formed by the 3rd distributed sensing device, the 3rd detectable signal is distributed by the described 3rd
Sensing device is exported to the fiber-optic signal demodulating system.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107228827A (en) * | 2017-07-26 | 2017-10-03 | 山东省科学院激光研究所 | Optical fiber sound wave gas monitoring device and system |
| CN109084817A (en) * | 2018-08-07 | 2018-12-25 | 吉林大学 | A kind of fibre optical sensor based on sine wave modulation |
| CN115882937A (en) * | 2022-11-30 | 2023-03-31 | 江苏亮点光电研究有限公司 | Optical time domain reflection-based optical fiber laser state online monitoring optical path and method |
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2016
- 2016-11-23 CN CN201621257791.7U patent/CN206291958U/en active Active
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107228827A (en) * | 2017-07-26 | 2017-10-03 | 山东省科学院激光研究所 | Optical fiber sound wave gas monitoring device and system |
| CN107228827B (en) * | 2017-07-26 | 2024-01-26 | 山东省科学院激光研究所 | Optical fiber sound wave gas monitoring device and system |
| CN109084817A (en) * | 2018-08-07 | 2018-12-25 | 吉林大学 | A kind of fibre optical sensor based on sine wave modulation |
| CN109084817B (en) * | 2018-08-07 | 2019-09-13 | 吉林大学 | A kind of fibre optical sensor based on sine wave modulation |
| CN115882937A (en) * | 2022-11-30 | 2023-03-31 | 江苏亮点光电研究有限公司 | Optical time domain reflection-based optical fiber laser state online monitoring optical path and method |
| CN115882937B (en) * | 2022-11-30 | 2024-01-09 | 江苏亮点光电研究有限公司 | Optical time domain reflection-based optical fiber laser state online monitoring light path and method |
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