CN104089636A - Double-peak stimulative type monitor based on Brillouin scattering - Google Patents
Double-peak stimulative type monitor based on Brillouin scattering Download PDFInfo
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- CN104089636A CN104089636A CN201410337617.2A CN201410337617A CN104089636A CN 104089636 A CN104089636 A CN 104089636A CN 201410337617 A CN201410337617 A CN 201410337617A CN 104089636 A CN104089636 A CN 104089636A
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Abstract
Provided is a double-peak stimulative type monitor based on Brillouin scattering. Two paths of sine positive half cycle pulsed light are continuously sent to a sensor fiber in each period, Brillouin scattering light generated by a single sound wave can generate interference, back Brillouin scattering light received by a coupler is the result of mutual interference, a local oscillator oscillates, measuring frequency resolution and spatial resolution are improved at the same time, and contradiction between the measuring frequency resolution and spatial resolution is solved. Single mode fibers are encapsulated by adopting carbon fibers, clearances of the carbon fibers are soaked through epoxy resin, and a single mode fiber external coating layer is formed. The double-peak stimulative type monitor based on the Brillouin scattering has the advantages that the intensity of a Brillouin spectrum is improved, Brillouin frequency shift is obtained accurately, and the spatial resolution and measurement accuracy of a system are improved. The carbon fibers are light and have the advantages of being high in intensity and resist to corrosion, high temperature, high pressure, fatigue and the like. Due to the fact that the carbon fibers are solidified outside the optical fibers, the optical fibers only have axial strain, radial train is approximate to zero, and the measuring sensitivity of the optical fibers is more than doubled.
Description
Technical field
The present invention relates to test and measuring field, relate in particular to a kind of based on the bimodal excitation formula of Brillouin scattering monitor.
Background technology
Electrification is the important symbol of modern social development's level, and electric power is closely bound up as basic energy resource and modern society, and power grid security maintains national security.Along with the rapid growth of Electricity Demand, district management and on national network implementation, guarantee power grid security economical operation, improves efficiency of energy utilization and become the key and urgent problem that China's electric system faces.
At present, Brillouin sensing device is widely used in electrified field, sharpest edges are to realize the long-distance distributed measurement of temperature and strain, its spatial resolution can reach centimetre-sized, and distance sensing can reach kilometers up to a hundred, but at present general use procedure, the pulse signal that RF-MW Photonics modulator in Brillouin's system sends is unimodal pulse, these those length that disappear of the frequency of brillouin frequency spectrometry and resolution, conflicting, do not reach the effect simultaneously improving; And transmission and distribution line spreads all over China various places, in long-time running, be subject to the impacts such as sleet, freezing, sunshine, electromagnetic induction, chemical corrosion and electric charge current-carrying capacity, the load variations of transmission and distribution line or aging be can cause, thereby the variation of transmission and distribution line temperature, the variation of stress caused.
Summary of the invention
The object of the present invention is to provide a kind of based on the bimodal excitation formula of Brillouin scattering monitor, adopt bimodal excitation formula pulse signal, frequency resolution and the spatial resolution of brillouin frequency spectrometry improve simultaneously, solved contradiction between the two, and the surrounding of single-mode fiber encapsulates by PAN-based carbon fiber, carbon fiber gap infiltrates with epoxy resin, can improve spatial resolution and the measuring accuracy of system, the single-mode fiber of carbon coated fiber also has high strength, corrosion-resistant, high temperature resistant, high pressure resistant, endurance, anti-hydrogen and the characteristic such as disturbs.
For achieving the above object, the present invention realizes by the following technical solutions:
A kind of based on the bimodal excitation formula of Brillouin scattering monitor, comprise semiconductor laser, coupling mechanism one, coupling mechanism two, coupling mechanism three, Polarization Controller one, Polarization Controller two, RF-MW Photonics modulator, photodetector, pulse producer, microwave mixer, local oscillator, matched filter, information acquisition and processor, single-mode fiber, described semiconductor laser is connected with the input end of coupling mechanism one, an output terminal of coupling mechanism one is connected with Polarization Controller one, Polarization Controller one is connected with RF-MW Photonics modulator, flutter generator is arranged on RF-MW Photonics modulator, RF-MW Photonics modulator is connected with an input end of coupling mechanism two, an output terminal of coupling mechanism two is connected with single-mode fiber, another output terminal of coupling mechanism two is connected with an input end of coupling mechanism three,
Another output terminal of coupling mechanism one is connected with Polarization Controller two, Polarization Controller two is connected with another input end of coupling mechanism three, the output terminal of coupling mechanism three is connected with processor successively with photodetector, microwave mixer, matched filter, information acquisition, and local oscillator is arranged on microwave mixer.
Described photodetector is PbSe detector.
Described semiconductor laser light source centre wavelength is 1550nm.
Utilize Brillouin's monitor to carry out the method for transducing signal monitoring, step is as follows:
The continuous light being sent by semiconductor laser is divided into two-way through coupling mechanism one, and a road light, as local oscillator light, through Polarization Controller two, arrives coupling mechanism three; After another Lu Guangjing Polarization Controller one, pulse producer effect by RF-MW Photonics modulator is modulated into two sinuous pulsation light, the time interval between two sinuous pulsation light waves is set in time phonon lifetime that is less than, pulsation light wave enters single-mode fiber through coupling mechanism two, the Brillouin scattering dorsad producing enters the detection that is concerned with of coupling mechanism three and local oscillator light, after relevant, high-frequency signal carries out down coversion by photodetector, microwave mixer, local oscillator and matched filter, then enters information acquisition and processor by matched filter.
The pulsed light that described RF-MW Photonics modulator produces is pulsation period 1.5ns, and the bimodal sinuous pulsation signal of pulsation interval 4ns, has realized spatial resolution 15cm, and temperature/stress measurement precision is the measurement of ± 0.5 ℃/± 15 μ ε.
The pulsed light that described RF-MW Photonics modulator produces is sinusoidal positive half cycle pulsed light.
Described single-mode fiber is single-mode fiber G.625, the polyacrylonitrile (PAN) base carbon fibre encapsulation in the surrounding of optical fiber with Φ 10 μ m, and carbon fiber gap infiltrates with epoxy resin, forms thus the outer overlay of single-mode fiber.
Compared with prior art, the invention has the beneficial effects as follows:
(1) adopt relevant bimodal exciting technique, improve the intensity of Brillouin's frequency spectrum.Utilize the oscillating characteristic of Brillouin's frequency spectrum, accurately obtain Brillouin shift; When making full use of the strong coherence of scattered light, adopt heterodyne coherent method to detect brillouin frequency shifting signal, improve spatial resolution and the measuring accuracy of system.
(2) carbon fiber very light weight, is applicable to being laid on overhead power transmission line with the Fibre Optical Sensor of its encapsulation, and simultaneously carbon fiber also has high strength, corrosion-resistant, high temperature resistant, high pressure resistant, endurance, anti-hydrogen and the characteristic such as disturbs.Because carbon fiber is solidificated in outer fiber, make optical fiber only have axial strain, radial strain is approximately zero, optical fiber measurement sensitivity is doubled many.
Accompanying drawing explanation
Fig. 1 is the bimodal excitation formula of the present invention Brillouin sensing schematic diagram.
Fig. 2 is the single-mode fiber sectional view of carbon coated fiber.
1-semiconductor laser 2-coupling mechanism one 3-Polarization Controller one 4-Polarization Controller two 5-RF-MW Photonics modulator 6-pulse producer 7-coupling mechanism two 8-single-mode fiber 9-coupling mechanism three 10-photodetector 11-microwave mixer 12-local oscillator 13-matched filter 14-information acquisition and processor 15-carbon fiber 16-epoxy resin
Embodiment
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is further illustrated:
As shown in Figure 1, a kind of based on the bimodal excitation formula of Brillouin scattering monitor, by semiconductor laser 1, coupling mechanism 1, Polarization Controller 1, Polarization Controller 24, RF-MW Photonics modulator 5, pulse producer 6, coupling mechanism 27, single-mode fiber 8 coupling mechanisms 39, photodetector 10, microwave mixer 11, local oscillator 12, matched filter 13, information acquisition and processor 14 form, described semiconductor laser 1 is connected with the input end of coupling mechanism 1, an output terminal of coupling mechanism 1 is connected with Polarization Controller 1, Polarization Controller 1 is connected with RF-MW Photonics modulator 5, flutter generator 6 is arranged on RF-MW Photonics modulator 5, RF-MW Photonics modulator 5 is connected with an input end of coupling mechanism 27, an output terminal of coupling mechanism 27 is connected with single-mode fiber 8, another output terminal of coupling mechanism 27 is connected with an input end of coupling mechanism 39,
Another output terminal of coupling mechanism 1 is connected with Polarization Controller 24, Polarization Controller 24 is connected with another input end of coupling mechanism 39, the output terminal of coupling mechanism 39 is connected with processor 14 successively with photodetector 10, microwave mixer 11, matched filter 13, information acquisition, and local oscillator 12 is arranged on microwave mixer 11.
Described photodetector 10 is PbSe detector.
Described semiconductor laser 1 light source center wavelength is 1550nm.
The method of utilizing described Brillouin's monitor to carry out transducing signal monitoring, detailed process is as follows:
The continuous light being sent by semiconductor laser 1 is divided into two-way through coupling mechanism 1, and a road light, as local oscillator light, through Polarization Controller 24, arrives coupling mechanism 39, after another Lu Guangjing Polarization Controller 1, pulse producer 6 effects by RF-MW Photonics modulator 5 are modulated into two sinuous pulsation light, the time interval between two sinuous pulsation light waves is set in time phonon lifetime that is less than, pulsation light wave enters single-mode fiber 8 through coupling mechanism 27, the Brillouin scattering dorsad producing enters the detection that is concerned with of coupling mechanism 39 and local oscillator light, after relevant, high-frequency signal is by photodetector 10, microwave mixer 11, local oscillator 12 and matched filter 13 carry out down coversion, by matched filter 13, enter information acquisition and processor 14 again.
The pulsed light that described RF-MW Photonics modulator 5 produces is pulsation period 1.5ns, and the bimodal sinuous pulsation signal of pulsation interval 4ns, has realized spatial resolution 15cm, and temperature/stress measurement precision is the measurement of ± 0.5 ℃/± 15 μ ε.
The pulsed light that described RF-MW Photonics modulator 5 produces is sinusoidal positive half cycle pulsed light.
Described single-mode fiber 8 is single-mode fiber G.625, polyacrylonitrile (PAN) base carbon fibre 15 encapsulation in the surrounding of optical fiber with Φ 10 μ m, and carbon fiber gap infiltrates with epoxy resin 16, forms thus the outer overlay of single-mode fiber 8.
Within each cycle, to sensor fibre, send two positive half cycle pulsed lights of sine continuously, the Brillouin scattering being produced by single sound wave can interfere, the result that the Brillouin scattering dorsad that coupling mechanism 39 receives is only interfered mutually, by local oscillator, vibrated again, survey frequency resolution and spatial resolution improve simultaneously, have solved contradiction between the two.
Polarization Controller can guarantee that input polarisation of light direction overlaps with its light transmission shaft, makes incident light all enter RF-MW Photonics modulator; Polarization Controller can also suppress polarization and rise and fall, reduce not mate because of polarization the signal fluctuation causing, after relevant, high-frequency signal carries out down coversion by photodetector, microwave mixer, local oscillator and matched filter, by matched filter, enter information acquisition and processor again, finally monitor out the data of temperature and stress.
Adopt relevant bimodal exciting technique, improve the intensity of Brillouin's frequency spectrum.Utilize the oscillating characteristic of Brillouin's frequency spectrum, accurately obtain Brillouin shift; When making full use of the strong coherence of scattered light, adopt heterodyne coherent method to detect brillouin frequency shifting signal, improve spatial resolution and the measuring accuracy of system.
Claims (7)
1. one kind based on the bimodal excitation formula of Brillouin scattering monitor, comprise semiconductor laser, coupling mechanism one, coupling mechanism two, coupling mechanism three, Polarization Controller one, Polarization Controller two, RF-MW Photonics modulator, photodetector, pulse producer, microwave mixer, local oscillator, matched filter, information acquisition and processor, single-mode fiber, it is characterized in that:
Described semiconductor laser is connected with the input end of coupling mechanism one, an output terminal of coupling mechanism one is connected with Polarization Controller one, Polarization Controller one is connected with RF-MW Photonics modulator, flutter generator is arranged on RF-MW Photonics modulator, RF-MW Photonics modulator is connected with an input end of coupling mechanism two, an output terminal of coupling mechanism two is connected with single-mode fiber, and another output terminal of coupling mechanism two is connected with an input end of coupling mechanism three;
Another output terminal of coupling mechanism one is connected with Polarization Controller two, Polarization Controller two is connected with another input end of coupling mechanism three, the output terminal of coupling mechanism three is connected with processor successively with photodetector, microwave mixer, matched filter, information acquisition, and local oscillator is arranged on microwave mixer.
2. according to claim 1 a kind ofly it is characterized in that based on the bimodal excitation formula of Brillouin scattering monitor, described photodetector is PbSe detector.
3. according to claim 1 a kind ofly it is characterized in that based on the bimodal excitation formula of Brillouin scattering monitor, described semiconductor laser light source centre wavelength is 1550nm.
4. utilize the method based on the monitoring of the bimodal excitation formula of Brillouin scattering monitor described in claim 1, it is characterized in that:
The continuous light being sent by semiconductor laser is divided into two-way through coupling mechanism one, and a road light, as local oscillator light, through Polarization Controller two, arrives coupling mechanism three; After another Lu Guangjing Polarization Controller one, pulse producer effect by RF-MW Photonics modulator is modulated into two sinuous pulsation light, the time interval between two sinuous pulsation light waves is set in time phonon lifetime that is less than, pulsation light wave enters single-mode fiber through coupling mechanism two, the Brillouin scattering dorsad producing enters the detection that is concerned with of coupling mechanism three and local oscillator light, after relevant, high-frequency signal carries out down coversion by photodetector, microwave mixer, local oscillator and matched filter, then enters information acquisition and processor by matched filter.
5. according to claim 4 a kind of based on the bimodal excitation formula of Brillouin scattering monitor, it is characterized in that, the pulsed light that described RF-MW Photonics modulator produces is pulsation period 1.5ns, the bimodal sinuous pulsation signal of pulsation interval 4ns, realized spatial resolution 15cm, temperature/stress measurement precision is the measurement of ± 0.5 ℃/± 15 μ ε.
6. according to claim 4 a kind ofly it is characterized in that based on the bimodal excitation formula of Brillouin scattering monitor, the pulsed light that described RF-MW Photonics modulator produces be sinusoidal just half cycle pulsed light.
7. according to claim 1 a kind of based on the bimodal excitation formula of Brillouin scattering monitor, it is characterized in that, described single-mode fiber is single-mode fiber G.625, surrounding at optical fiber encapsulates with the polyacrylonitrile (PAN) base carbon fibre of Φ 10 μ m, carbon fiber gap infiltrates with epoxy resin, forms thus the outer overlay of single-mode fiber.
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Cited By (4)
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| CN108414114A (en) * | 2018-03-26 | 2018-08-17 | 李青 | A kind of optical fiber sensing probe and fiber temperature sensing system |
| CN111051832A (en) * | 2017-05-11 | 2020-04-21 | 费布斯光学公司 | Photoelectric device for optical fiber distributed measurement |
| CN114777899A (en) * | 2022-03-29 | 2022-07-22 | 孙安 | Monitoring system and method based on distributed sensor |
| CN114777899B (en) * | 2022-03-29 | 2024-04-26 | 孙安 | Monitoring system and method based on distributed sensor |
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