CN202182702U - Brillouin optical time domain analyzer using chaotic laser method - Google Patents
Brillouin optical time domain analyzer using chaotic laser method Download PDFInfo
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- CN202182702U CN202182702U CN2011202758580U CN201120275858U CN202182702U CN 202182702 U CN202182702 U CN 202182702U CN 2011202758580 U CN2011202758580 U CN 2011202758580U CN 201120275858 U CN201120275858 U CN 201120275858U CN 202182702 U CN202182702 U CN 202182702U
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Abstract
The utility model discloses a Brillouin optical time domain analyzer using a chaotic laser method. The optical fiber Brillouin optical time domain analyzer is made by utilizing a chaotic laser related principles and the strain, temperature effect and optical time domain principle of coherently amplified Brillouin scattering lights. In the utility model, a chaotic laser is adopted as a local referent light source and a pumping signal light source of the Brillouin optical time domain analyzer at the same time. In the utility model, by utilizing related principles of chaotic laser having super wide frequency width, and through related processing of a signal light and a local light, high spatial resolution is obtained, thereby improving the reliability of a sensor and the spatial resolution to a centimeter degree, increasing the number of pumping photons entering into a sensing fiber, improving the signal to noise ratio of a sensor system by 10 dB, and improving the detecting distance of the sensor to 50 km. By adopting the chaotic laser as the local referent light source and the pumping signal light source of the Brillouin optical time domain analyzer, the difficulty in locking a narrow-band detecting laser and a narrow-band pumping laser is overcome, thereby improving the stability of a system.
Description
Technical field
The utility model relates to the relevant Brillouin light time domain analyzer of a kind of chaotic laser light, belongs to the distributed fiberoptic sensor technical field.
Background technology
In the optical fiber Brillouin light time domain analyzer field,, adopt the burst pulse light source in order to improve the spatial resolution of sensor; But, limited the incident power of optical fiber, therefore owing to the nonlinear effect of optical fiber; Realize long distance, the optical fiber Brillouin light time domain analyzer of high spatial resolution is difficulty very, the method for traditional compression laser instrument pulsewidth; The method that dipulse is right; Be difficult to realize long metric space resolution less than 1 meter effect, and spatial resolution is relevant with measurement length, the signal to noise ratio (S/N ratio) of system is also low.And prior art still has difficulties for locking arrowband detecting laser and arrowband pump laser.Therefore need a kind of Brillouin light time domain analyzer technology at present badly; Can improve the spatial resolution and the measuring distance of sensing system effectively; Satisfy the safety and Health monitoring of petroleum pipe line, transferring electric power cable in recent years, to the demand of strain of very-long-range fully distributed fiber and TEMP net.
The utility model content
The purpose of the utility model is, a kind of chaotic laser light Brillouin light time domain analyzer of being correlated with is provided.The spatial resolution that it can improve sensing system effectively reaches centimetre-sized, and measuring distance reaches 50km.
The technical scheme of the utility model: the chaotic laser light Brillouin light time domain analyzer of being correlated with; Characteristics are: it is to utilize the chaotic laser light relative theory; The optical fiber Brillouin light time domain analyzer that strain, temperature effect and the optical time domain reflection principle of the relevant Brillouin scattering that amplifies processed, it utilizes local reference light source and the pump signal light source of same chaotic laser light device as Brillouin light time domain analyzer.Adopt the light pulse sequence of chaotic laser light relative theory random fluctuation on time domain, through the light dorsad of sensor fibre and the relevant treatment of local reference light, the spatial resolution that can improve sensing system reaches centimetre-sized; Adopt same chaotic laser light source to overcome the difficulty that optical fiber Brillouin light time domain analyzer locks detecting laser and pump laser frequency strictly; Improved the signal to noise ratio (S/N ratio) 10dB of sensing system, the measurement length that has correspondingly improved sensor reaches 50km.It comprises chaotic laser light device, second optical fiber splitter, photomodulator, first EDFA Erbium-Doped Fiber Amplifier, second adjustable optical attenuator, polarization mode scrambler, isolator, sensor fibre, second EDFA Erbium-Doped Fiber Amplifier, second fiber optical circulator, the 3rd fiber optical circulator, fiber grating reflecting filter, photelectric receiver module, digital signal processor and computing machine; The output terminal of chaotic laser light device links to each other with the input end of second optical fiber splitter; An output terminal of second optical fiber splitter links to each other with photomodulator, and links to each other with an end of sensor fibre via first EDFA Erbium-Doped Fiber Amplifier, second adjustable optical attenuator, polarization mode scrambler, polarization mode scrambler, isolator successively; Another output terminal of second optical fiber splitter links to each other with second EDFA Erbium-Doped Fiber Amplifier; And link to each other with the other end of sensor fibre via second fiber optical circulator; Second fiber optical circulator also links to each other with the 3rd fiber optical circulator; Also be connected with the fiber grating reflecting filter on the 3rd fiber optical circulator, the output terminal of the 3rd fiber optical circulator links to each other with the photelectric receiver module, and the output terminal of photelectric receiver module links to each other with computing machine with digital signal processor.Through photelectric receiver module, digital signal processor and computing machine chaotic laser light signal and local reference light heterodyne with sensor fibre; The line correlation of going forward side by side is handled and the Fast Fourier Transform (FFT) demodulation, acquisition 50km sensor fibre high spatial resolution at the scene reach the strain, temperature information of centimetre magnitude and send the remote monitoring net to through wireless network or internet.
In the relevant Brillouin light time domain analyzer of aforesaid chaotic laser light, said chaotic laser light device comprises semiconductor LD laser instrument, first Polarization Controller, first fiber optical circulator, first optical fiber splitter, first adjustable optical attenuator and second Polarization Controller; Semiconductor LD laser instrument joins through an input port of first Polarization Controller and first fiber optical circulator; The output terminal of first fiber optical circulator links to each other with the first optical fiber splitter input end; An output terminal of first optical fiber splitter links to each other with the output terminal of first adjustable optical attenuator; And link to each other with another input end of first fiber optical circulator through second Polarization Controller, warp first Polarization Controller feeds back to semiconductor LD laser instrument again; Another output terminal of first optical fiber splitter links to each other with the input end of second optical fiber splitter.
In the relevant Brillouin light time domain analyzer of aforesaid chaotic laser light, said semiconductor LD laser instrument is a Distributed Feedback Laser, and operation wavelength is 1550.0nm, and output power is 10dBm; The branching ratio of first optical fiber splitter is 20: 80; The branching ratio of second optical fiber splitter is 30: 70.
In the relevant Brillouin light time domain analyzer of aforesaid chaotic laser light, said photomodulator is lithium niobate Mach-Ze Deer modulator (Mach-Zehnder modulator (MZM)).Through the frequency reduction 11GHz of computer control with laser instrument.
In the relevant Brillouin light time domain analyzer of aforesaid chaotic laser light, said sensor fibre is 50km single mode communication G652 optical fiber or 50km LEAF optical fiber.
In the relevant Brillouin light time domain analyzer of aforesaid chaotic laser light, the centre wavelength of said fiber grating reflecting filter is 1550.08nm, and spectral bandwidth is 0.1nm.But other light of filtering, the Stokes stimulated Brillouin scattering flashlight that allows sensor fibre is through the line correlation processing of going forward side by side of the 3rd fiber optical circulator and local reference light heterodyne reception.
In the relevant Brillouin light time domain analyzer of aforesaid chaotic laser light, said photelectric receiver module is that photodetector, prime amplifier and main amplifier more than the 2Ghz formed by frequency response.
In the relevant Brillouin light time domain analyzer of aforesaid chaotic laser light, described digital signal processor is that the high speed 5G sampling rate of relevant treatment and Fast Fourier Transform (FFT) software and the digital signal processor of 500MHz frequency range are arranged.
The chaotic laser light relative theory:
Semiconductor laser produces the ultra wide band chaotic laser of random fluctuation constantly when receiving the light feedback; Its correlation curve has the δ function shape; The bandwidth of the non-linear chaotic oscillation of semiconductor laser can realize high resolving power, the high-precision measurement irrelevant with measuring length greater than 15GHz.
If reference light is f (t), detection light is g (t)=Kf (t-τ)
Cross correlation function:
When τ=τ 0, there is peak value in cross correlation function, and cross-correlation peak value is with to survey light intensity relevant.Gather, add up surveying light and reference light through digital signal processor and computing machine, relevant treatment and fast Fourier transform are handled, the information of strain and temperature on the acquisition sensor fibre.By the bandwidth of non-linear chaotic oscillation, the spatial resolution of the bandwidth of photelectric receiver module and digital processing system decision Brillouin light time domain analyzer has determined Brillouin light time domain analyzer to measure length by the signal to noise ratio (S/N ratio) of system.
The principle of work of Brillouin's Time Domain Analyzer:
In optical fiber; The exploring laser light of incident optical; Pumping laser and optical fiber produce nonlinear interaction, and light wave produces sound wave through electrostriction in optical fiber, cause the periodic modulation (refractive-index grating) of optical fibre refractivity; Produce the stimulated Brillouin scattering light that frequency moves down, the frequency displacement vB of the Brillouin scattering dorsad that in optical fiber, produces is:
vB＝2nv/λ (2)
Wherein n is the refractive index at lambda1-wavelength λ place, and v is the velocity of sound in the optical fiber, and to silica fibre, near λ=1550nm, vB is about 11GHz.
Brillouin scattering optical frequency shift vB in optical fiber has strain and temperature effect
The frequency displacement of Brillouin scattering
δv
B＝C
vεδε+C
vTδT (4)
Wherein the coefficient of strain Cv ε of frequency displacement and temperature coefficient CvT do
C
vε＝0.0482±0.004MHz/με，C
vT＝1.10±0.02MHz/K
Compared with prior art; The utility model adopts the chaotic laser light relative theory, and chaotic laser light has the ultra broadband frequency range, obtains high spatial resolution through the relevant treatment to flashlight and local reference light; The reliability and the spatial resolution that have improved sensor effectively can reach centimetre-sized; The pulse train of chaotic laser light has increased the pump light subnumber that gets into sensor fibre, has improved the signal to noise ratio (S/N ratio) 10dB of sensing system, and the measurement length that has increased Brillouin light time domain analyzer can reach 50km; Adopt same chaotic laser light device also to solve the difficulty that locks arrowband detecting laser and arrowband pump laser, improved the steady intact property of system as the local reference light source and the pump signal light source of Brillouin light time domain analyzer.
Description of drawings
Fig. 1 is the structural representation of the utility model.
Embodiment
Below in conjunction with accompanying drawing and embodiment the utility model is further described, but not as the foundation to the utility model restriction.
Embodiment.The chaotic laser light Brillouin light time domain analyzer of being correlated with; It is to utilize the chaotic laser light relative theory; The optical fiber Brillouin light time domain analyzer that strain, temperature effect and the optical time domain reflection principle of the relevant Brillouin scattering that amplifies processed, it utilizes probe source and the pump signal light source of same chaotic laser light device as Brillouin light time domain analyzer.It comprises chaotic laser light device, second optical fiber splitter 16, photomodulator 17, first EDFA Erbium-Doped Fiber Amplifier 18, second adjustable optical attenuator 19, polarization mode scrambler 20, isolator 21, sensor fibre 22, second EDFA Erbium-Doped Fiber Amplifier 23, second fiber optical circulator 24, the 3rd fiber optical circulator 25, fiber grating reflecting filter 26, photelectric receiver module 27, digital signal processor 28 and computing machine 29; The output terminal of chaotic laser light device links to each other with the input end of second optical fiber splitter 16; An output terminal of second optical fiber splitter 16 links to each other with photomodulator 17, and links to each other with an end of sensor fibre 22 via first EDFA Erbium-Doped Fiber Amplifier 18, second adjustable optical attenuator 19, polarization mode scrambler 20, polarization mode scrambler 20, isolator 21 successively; Another output terminal of second optical fiber splitter 16 links to each other with second EDFA Erbium-Doped Fiber Amplifier 23; And link to each other with the other end of sensor fibre 22 via second fiber optical circulator 24; Second fiber optical circulator 24 also links to each other with the 3rd fiber optical circulator 25; Also being connected with fiber grating reflecting filter 26 on the 3rd fiber optical circulator 25 links to each other; The output terminal of the 3rd fiber optical circulator 25 links to each other with photelectric receiver module 27, and the output terminal of photelectric receiver module 27 links to each other with computing machine 29 with digital signal processor 28.
Said chaotic laser light device comprises semiconductor LD laser instrument 10, first Polarization Controller 11, first fiber optical circulator 12, first optical fiber splitter 13, first adjustable optical attenuator 14 and second Polarization Controller 15; Semiconductor LD laser instrument 10 joins through an input port of first Polarization Controller 11 and first fiber optical circulator 12; The output terminal of first fiber optical circulator 12 links to each other with first optical fiber splitter, 13 input ends; An output terminal of first optical fiber splitter 13 links to each other with the output terminal of first adjustable optical attenuator 14; And link to each other with another input end of first fiber optical circulator 12 through second Polarization Controller 15, warp first Polarization Controller 11 feeds back to semiconductor LD laser instrument 10 again; Another output terminal of first optical fiber splitter 13 links to each other with the input end of second optical fiber splitter 16.
Said semiconductor LD laser instrument (10) is a Distributed Feedback Laser, and operation wavelength is 1550.0nm, and output power is 10dBm; The branching ratio of first optical fiber splitter 13 is 20: 80; The branching ratio of second optical fiber splitter 16 is 30: 70.
Said photomodulator 17 is lithium niobate Mach-Ze Deer modulators.
Said sensor fibre 22 is 50km single mode communication G652 optical fiber or 50km LEAF optical fiber.
The centre wavelength of said fiber grating reflecting filter 26 is 1550.08nm, and spectral bandwidth is 0.1nm.
Said photelectric receiver module 27 is that photodetector, prime amplifier and main amplifier more than the 2Ghz formed by frequency response.
Described digital signal processor 28 is for having the high speed 5G sampling rate of relevant treatment and Fast Fourier Transform (FFT) software and the digital signal processor of 500MHz frequency range.
The principle of work of the utility model: the chaotic laser light device is divided into two bundles through optical fiber splitter; Wherein a branch of ultra wide band chaotic laser is as local reference light; Through photomodulator, the frequency decline 11GHz with laser instrument amplifies through EDFA Erbium-Doped Fiber Amplifier; Get into sensor fibre through the fiber optic disturb mode device; Another bundle ultra wide band chaotic laser pulse sequence is through Erbium-Doped Fiber Amplifier (EDFA), and second circulator gets into sensor fibre as pump signal light, dorsad the stimulated Brillouin optical v that has strain and temperature information in the sensor fibre
0± v
BThrough the fiber grating reflective filter, filtering v
0, v
0+ v
B, obtain v
0-v
BFlashlight; Pass through the photelectric receiver module with local reference light; Digital signal processor and computing machine demodulation are also made relevant treatment and Fast Fourier Transform (FFT), and by optical time domain reflection principle location, each section gone up the strain and the temperature information of high spatial resolution on the acquisition sensor fibre.
Claims (7)
1. the relevant Brillouin light time domain analyzer of chaotic laser light, it is characterized in that: it comprises chaotic laser light device, second optical fiber splitter (16), photomodulator (17), first EDFA Erbium-Doped Fiber Amplifier (18), second adjustable optical attenuator (19), polarization mode scrambler (20), isolator (21), sensor fibre (22), second EDFA Erbium-Doped Fiber Amplifier (23), second fiber optical circulator (24), the 3rd fiber optical circulator (25), fiber grating reflecting filter (26), photelectric receiver module (27), digital signal processor (28) and computing machine (29); The output terminal of chaotic laser light device links to each other with the input end of second optical fiber splitter (16); An output terminal of second optical fiber splitter (16) links to each other with photomodulator (17), and links to each other with an end of sensor fibre (22) via first EDFA Erbium-Doped Fiber Amplifier (18), second adjustable optical attenuator (19), polarization mode scrambler (20), polarization mode scrambler (20), isolator (21) successively; Another output terminal of second optical fiber splitter (16) links to each other with second EDFA Erbium-Doped Fiber Amplifier (23); And link to each other via the other end of second fiber optical circulator (24) with sensor fibre (22); Second fiber optical circulator (24) also links to each other with the 3rd fiber optical circulator (25); The 3rd fiber optical circulator (also is connected with fiber grating reflecting filter (26) on 25; The output terminal of the 3rd fiber optical circulator (25) links to each other with photelectric receiver module (27), and the output terminal of photelectric receiver module (27) links to each other with computing machine (29) with digital signal processor (28).
2. the chaotic laser light according to claim 1 Brillouin light time domain analyzer of being correlated with, it is characterized in that: said chaotic laser light device comprises semiconductor LD laser instrument (10), first Polarization Controller (11), first fiber optical circulator (12), first optical fiber splitter (13), first adjustable optical attenuator (14) and second Polarization Controller (15); Semiconductor LD laser instrument (10) joins through the input port of first Polarization Controller (11) with first fiber optical circulator (12); The output terminal of first fiber optical circulator (12) links to each other with first optical fiber splitter (13) input end; An output terminal of first optical fiber splitter (13) links to each other with the output terminal of first adjustable optical attenuator (14); And link to each other with another input end of first fiber optical circulator (12) through second Polarization Controller (15), warp first Polarization Controller (11) feeds back to semiconductor LD laser instrument (10) again; Another output terminal of first optical fiber splitter (13) links to each other with the input end of second optical fiber splitter (16).
3. the chaotic laser light according to claim 2 Brillouin light time domain analyzer of being correlated with, it is characterized in that: said semiconductor LD laser instrument (10) is a Distributed Feedback Laser, and operation wavelength is 1550.0nm, and output power is 10dBm; The branching ratio of first optical fiber splitter (13) is 20: 80; The branching ratio of second optical fiber splitter (16) is 30: 70.
4. the chaotic laser light according to claim 1 Brillouin light time domain analyzer of being correlated with, it is characterized in that: said photomodulator (17) is lithium niobate Mach-Ze Deer modulator.
5. the chaotic laser light according to claim 1 Brillouin light time domain analyzer of being correlated with, it is characterized in that: said sensor fibre (22) is 50km single mode communication G652 optical fiber or 50kmLEAF optical fiber.
6. the chaotic laser light according to claim 1 Brillouin light time domain analyzer of being correlated with, it is characterized in that: the centre wavelength of said fiber grating reflecting filter (26) is 1550.08nm, spectral bandwidth is 0.1nm.
7. the chaotic laser light according to claim 1 Brillouin light time domain analyzer of being correlated with is characterized in that: said photelectric receiver module (27) is that photodetector, prime amplifier and main amplifier more than the 2Ghz formed by frequency response.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104180830A (en) * | 2013-05-24 | 2014-12-03 | 无锡万润光子技术有限公司 | Distributed optical fiber fizeau interferometer based on light time domain reflection principle |
| CN110375800A (en) * | 2019-06-03 | 2019-10-25 | 太原理工大学 | A kind of sensing device and method based on super continuous spectrums Brillouin light time domain analyzer |
| CN112880865A (en) * | 2021-03-25 | 2021-06-01 | 太原理工大学 | Ultra-long-distance high-spatial-resolution Raman optical fiber dual-parameter sensing system and method |
| CN112880866A (en) * | 2021-03-25 | 2021-06-01 | 太原理工大学 | Long-distance high-spatial-resolution Raman fiber multi-parameter sensing system and method |
| CN116073897A (en) * | 2023-03-06 | 2023-05-05 | 华南师范大学 | Optical time domain reflectometer based on broadband random photoelectric oscillator and measuring method thereof |
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2011
- 2011-08-01 CN CN2011202758580U patent/CN202182702U/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104180830A (en) * | 2013-05-24 | 2014-12-03 | 无锡万润光子技术有限公司 | Distributed optical fiber fizeau interferometer based on light time domain reflection principle |
| CN110375800A (en) * | 2019-06-03 | 2019-10-25 | 太原理工大学 | A kind of sensing device and method based on super continuous spectrums Brillouin light time domain analyzer |
| CN110375800B (en) * | 2019-06-03 | 2021-03-02 | 太原理工大学 | Sensing device and method based on super-continuum spectrum Brillouin optical time domain analyzer |
| CN112880865A (en) * | 2021-03-25 | 2021-06-01 | 太原理工大学 | Ultra-long-distance high-spatial-resolution Raman optical fiber dual-parameter sensing system and method |
| CN112880866A (en) * | 2021-03-25 | 2021-06-01 | 太原理工大学 | Long-distance high-spatial-resolution Raman fiber multi-parameter sensing system and method |
| CN112880865B (en) * | 2021-03-25 | 2022-05-13 | 太原理工大学 | Ultra-long-distance high-spatial-resolution Raman optical fiber dual-parameter sensing system and method |
| CN112880866B (en) * | 2021-03-25 | 2023-09-12 | 太原理工大学 | Long-distance high-spatial-resolution Raman fiber multi-parameter sensing system and method |
| CN116073897A (en) * | 2023-03-06 | 2023-05-05 | 华南师范大学 | Optical time domain reflectometer based on broadband random photoelectric oscillator and measuring method thereof |
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