CN102818582A - Optical fiber sensing system - Google Patents
Optical fiber sensing system Download PDFInfo
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- CN102818582A CN102818582A CN2012102700381A CN201210270038A CN102818582A CN 102818582 A CN102818582 A CN 102818582A CN 2012102700381 A CN2012102700381 A CN 2012102700381A CN 201210270038 A CN201210270038 A CN 201210270038A CN 102818582 A CN102818582 A CN 102818582A
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Abstract
本发明提供了一种光纤传感系统，包括：泵浦激光源，用于产生泵浦激光；波分复用器，用于传输泵浦激光和信号激光；DFB光纤激光器，包括：有源相移光纤，位于靠近波分复用器的一侧，用于利用泵浦激光泵浦产生与该DFB光纤激光器周围环境物理量相关的信号激光，并将该信号激光反向传输至波分复用器，反射光纤光栅，位于靠近传输光纤的一侧，用于反射由传输光纤产生的瑞利散射光；解调系统，与波分复用器的反向输出端相连接，用于从信号激光中解调出DFB光纤激光器的周围环境物理量。本发明可以在不增加光路复杂度和泵浦功率的情况下，提高光纤传感系统抗瑞利散射光的能力。
The invention provides an optical fiber sensing system, comprising: a pump laser source for generating pump laser light; a wavelength division multiplexer for transmitting pump laser light and signal laser light; a DFB fiber laser, comprising: an active phase Shifting optical fiber, located on the side close to the wavelength division multiplexer, is used to pump the pump laser to generate signal laser related to the physical quantity of the surrounding environment of the DFB fiber laser, and transmit the signal laser back to the wavelength division multiplexer , reflective fiber grating, located on the side close to the transmission fiber, used to reflect the Rayleigh scattered light generated by the transmission fiber; the demodulation system, connected with the reverse output end of the wavelength division multiplexer, used to extract from the signal laser Demodulate the physical quantity of the surrounding environment of the DFB fiber laser. The invention can improve the ability of the optical fiber sensor system to resist Rayleigh scattered light without increasing the complexity of the optical path and the pumping power.
Description
Technical field
The present invention relates to optics industry laser technique field, relate in particular to the optical fiber sensing system of a kind of application distribution feedback (distributed feedback is called for short DFB) fiber laser.
Background technology
Than common bragg grating (fiber Bragg grating) laser instrument; The DFB fiber laser have when being used for sensor simple in structure, anti-electromagnetic interference (EMI), compatible with fiber optic component, be easy to unique advantages such as wavelength-division multiplex, narrow linewidth, high power, low noise, obtained application widely in fields such as oil/mineral exploration, thing monitoring under water, circumference safety.
The DFB fiber laser is often grown the pumping of distance through Transmission Fibers in Application in Sensing, therefore, the DFB fiber laser will inevitably face the Rayleigh scattering in the Transmission Fibers.Though the Rayleigh scattering light in the optical fiber a little less than, possibly produce bigger influence to the stability of DFB fiber laser.
Fig. 1 is the synoptic diagram that DFB fiber laser Rayleigh scattering light produces in the prior art optical fiber sensing system.As shown in Figure 1, cause Rayleigh scattering owing to random variation takes place refractive index in the optical fiber manufacture process on the size littler than wavelength, in the short distance sensing, Rayleigh scattering light a little less than, can not form influence to laser instrument; In long-distance sensing, Rayleigh scattering light significantly strengthens, and has a strong impact on the performance of laser instrument, like frequency hopping, and noise rising etc.At this moment if the DFB fiber laser is used for transducing signal, will obtain a lot " false signal ", target formed erroneous judgement, thereby cause optical fiber sensing system malfunctioning.
At present, existing in the optical fiber sensing system of using the DFB fiber laser method of anti-Rayleigh scattering light mainly be the adjustment light channel structure, as in light path, introducing methods such as bending loss, isolator, polarization state control.These methods all have certain limitation, as make light path complicacy, needs improve pump power etc.
Summary of the invention
The technical matters that (one) will solve
For solving above-mentioned one or more problems, the invention provides a kind of optical fiber sensing system of the DFB of application fiber laser, with under the situation that does not increase light path complexity and pump power, improve the ability of the anti-Rayleigh scattering light of optical fiber sensing system.
(2) technical scheme
According to an aspect of the present invention, a kind of optical fiber sensing system is provided, has comprised: pump laser source is used to produce pumping laser; Wavelength division multiplexer; Its positive input is connected to semiconductor laser; Its reverse input end is connected to the DFB fiber laser, be used for the pumping laser that pump laser source produces is transferred to the DFB fiber laser, and the signal laser that the DFB fiber laser is excited to produce is transferred to demodulating system; The DFB fiber laser; Its front end is connected to forward output terminal and the reverse input end as the wavelength division multiplexer of same port; Its rear end is connected to next stage DFB fiber laser through Transmission Fibers, comprising: active phase shift optical fiber is positioned at the side near wavelength division multiplexer; Be used to utilize pumping laser pumping and the relevant signal laser of this DFB fiber laser surrounding environment physical quantity, and with this signal laser reverse transfer to wavelength division multiplexer; Reflection fiber grating is positioned at the side near Transmission Fibers, is used to reflect the Rayleigh scattering light that is produced by Transmission Fibers; Demodulating system is connected with the inverse output terminal of wavelength division multiplexer, is used for demodulating from signal laser the surrounding environment physical quantity of DFB fiber laser.
(3) beneficial effect
Can find out from technique scheme; The present invention uses the optical fiber sensing system of DFB fiber laser through increasing reflection fiber grating at ordinary optic fibre laser instrument one end; Improved the ability of the anti-Rayleigh scattering light of DFB fiber laser self, need not transform, need not improve pump power light path; Thereby cost is low, simple in structure, is easy to realize and promote.
Description of drawings
Fig. 1 is the synoptic diagram that DFB fiber laser Rayleigh scattering light produces in the prior art optical fiber sensing system;
Fig. 2 is the structural representation of embodiment of the invention optical fiber sensing system;
Fig. 3 is the structural representation of DFB fiber laser in the embodiment of the invention optical fiber sensing system.
[main element symbol description]
The 1-semiconductor laser; The 2-wavelength division multiplexer;
The 3-DFB fiber laser; The 4-Transmission Fibers;
The 5-demodulating system.
Embodiment
For making the object of the invention, technical scheme and advantage clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, to further explain of the present invention.
Need to prove that in accompanying drawing or instructions description, similar or identical part is all used identical figure number.And in the accompanying drawings, to simplify or convenient the sign.Moreover, the implementation that does not illustrate in the accompanying drawing or describe, the form of knowing for those of ordinary skill in the affiliated technical field.In addition,, should be appreciated that parameter need not definitely to equal corresponding value, but can in acceptable error margin or design constraint, be similar to corresponding value though this paper can provide the demonstration of the parameter that comprises particular value.
In one exemplary embodiment of the present invention, a kind of optical fiber sensing system of the DFB of application fiber laser is provided.As shown in Figure 2, this optical fiber sensing system comprises: pump laser source 1 is used to produce pumping laser; Wavelength division multiplexer 2; Its positive input is connected to semiconductor laser; Its reverse input end is connected to DFB fiber laser 3, be used for the pumping laser that pump laser source 1 produces is transferred to the DFB fiber laser, and the signal laser that the DFB fiber laser is excited to produce is transferred to demodulating system; DFB fiber laser 3, its front end are connected to forward output terminal and the reverse input end as the wavelength division multiplexer 2 of same port, and its rear end is connected to next stage DFB fiber laser through Transmission Fibers 4.As shown in Figure 3; DFB fiber laser 3 comprises: active phase shift optical fiber; Be positioned at a side, be used to utilize pumping laser pumping and the relevant signal laser of these DFB fiber laser 3 surrounding environment physical quantitys near wavelength division multiplexer 2, and with this signal laser reverse transfer to wavelength division multiplexer 2; High reflection fiber grating is positioned at the side near Transmission Fibers 4, is used to reflect the Rayleigh scattering light that is produced by Transmission Fibers 4; Demodulating system 5 is connected with the inverse output terminal of wavelength division multiplexer 2, is used for being demodulated by signal laser the surrounding environment physical quantity of DFB fiber laser 3.
In the present embodiment; Outside the DFB fiber laser faces that end of light reflection, increase reflection fiber grating, reduce additional grating end light reflection and get into the intensity in the active phase shift optical fiber resonator cavity, improved the ability of the anti-Rayleigh scattering light of DFB fiber laser itself; Need not transform light path; Need not improve pump power, thereby cost is low, simple in structure, is easy to realize and promote.
In order to realize the purpose of anti-Rayleigh scattering, in the preferred embodiment of the invention, the length of this DFB fiber laser 3 is 36～44mm; The length of high reflection fiber grating is 10～15mm, and reflectivity is preferably greater than 99.9% greater than 90%.
In order to prepare the DFB fiber laser 3 of present embodiment, at first, on Active Optical Fiber, write system one section common fiber laser, i.e. phase-shifted fiber grating; Then, this section optical fiber is blocked, write one section fiber grating that reflectivity is high of system at the one of which end through adding baffle plate.Certainly, the present invention is not exceeded with the DFB fiber laser of this kind method preparation.
In order to control the cost of whole system; Pump laser source adopts semiconductor laser; And pumping laser employing wavelength is the pumping laser of 980nm; Adopting wavelength is the signal laser of 1550nm, and wavelength division multiplexer, semiconductor laser and DFB fiber laser 3 are complementary with this pumping laser and signal laser.Certainly, also can adopt wavelength is the pumping laser of 1480nm, and adopting wavelength simultaneously is the signal laser of 1550nm, at this moment, also need adopt corresponding wavelength division multiplexer 2, semiconductor laser and DFB fiber laser 3.
As everyone knows, optical fiber sensing system can also comprise N-1 secondary DFB fiber laser, wherein N >=2 by the Transmission Fibers series connection.I level fiber laser in this N level DFB fiber laser is connected through I section Transmission Fibers with I+1 level fiber laser.This I level fiber laser comprises: active phase shift optical fiber; Be positioned at a side near I-1 level fiber laser; Be used to utilize pumping laser to produce and the relevant I level signal laser of this I level DFB fiber laser surrounding environment physical quantity, and this I level signal laser is transferred to wavelength division multiplexer 2; High reflection fiber grating is positioned at the side near I section Transmission Fibers, is used to reflect the Rayleigh scattering light that is produced by I section Transmission Fibers.Demodulating system 5 is used for demodulating I level DFB fiber laser surrounding environment physical quantity by I level signal laser.Wherein, the environmental physics amount is pressure, temperature or other physical quantitys.
Through the optical fiber sensing system and the optical fiber sensing system of the present invention that adopt the ordinary optic fibre laser instrument are carried out experiment, contrasted the ability of both anti-Rayleigh scattering lights.When the length of Transmission Fibers is 30m, adopt the frequency generation saltus step of the optical fiber sensing system of ordinary optic fibre laser instrument, stability worsens; And optical fiber sensing system of the present invention still keeps the characteristic of single-frequency.When the length of Transmission Fibers is 100m, the having good stability of optical fiber sensing system of the present invention, still correct transducing signal.
Need to prove that above-mentioned definition to each element is not limited in various concrete structures or the shape of mentioning in the embodiment, those of ordinary skill in the art can be to its replacement simply with knowing.
Above-described specific embodiment; The object of the invention, technical scheme and beneficial effect have been carried out further explain, and institute it should be understood that the above is merely specific embodiment of the present invention; Be not limited to the present invention; All within spirit of the present invention and principle, any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (8)
1. optical fiber sensing system comprises:
Pump laser source (1) is used to produce pumping laser;
Wavelength division multiplexer (2); Its positive input is connected to said pump laser source (1); Reverse input end is connected to DFB fiber laser (3); Be used for the pumping laser that pump laser source (1) produces is transferred to DFB fiber laser (3), and the signal laser that DFB fiber laser (3) is excited to produce is transferred to demodulating system (5);
DFB fiber laser (3), its front end are connected to forward output terminal and the reverse input end as the said wavelength division multiplexer (2) of same port, and its rear end is connected to next stage DFB fiber laser through Transmission Fibers (4), comprising:
Active phase shift optical fiber is positioned at the side near said wavelength division multiplexer (2), is used to utilize the pumping laser pumping to produce and the relevant signal laser of this DFB fiber laser surrounding environment physical quantity, and with this signal laser reverse transfer to said wavelength division multiplexer (2);
Reflection fiber grating is positioned at the side near said Transmission Fibers (4), is used for the Rayleigh scattering light that reflection is produced by said Transmission Fibers (4);
Demodulating system (5) is connected with the inverse output terminal of said wavelength division multiplexer (2), is used for demodulating from said signal laser the surrounding environment physical quantity of DFB fiber laser.
2. optical fiber sensing system according to claim 1, wherein, the reflectivity of said reflection fiber grating is greater than 90%.
3. optical fiber sensing system according to claim 2, wherein, the reflectivity of said reflection fiber grating is greater than 99.9%.
4. optical fiber sensing system according to claim 1, wherein, the length of said DFB fiber laser (3) is between 36～44mm; The length of said reflection fiber grating is between 10～15mm.
5. optical fiber sensing system according to claim 1, wherein, the wavelength of said pumping laser is 980nm or 1480nm, the wavelength of said signal laser is 1550nm.
6. optical fiber sensing system according to claim 5, wherein, said pump laser source (1) is a semiconductor laser.
7. according to each described optical fiber sensing system in the claim 1 to 6, also comprise: by N-1 secondary DFB fiber laser, wherein N >=2 of Transmission Fibers series connection;
For the I level fiber laser in this N-1 the secondary DFB fiber laser, it is connected through I section Transmission Fibers with I+1 level fiber laser, comprising:
Active phase shift optical fiber; Be positioned at a side near I-1 level fiber laser; Be used to utilize said pumping laser to produce and the relevant I level signal laser of this I level DFB fiber laser surrounding environment physical quantity, and this I level signal laser is transferred to wavelength division multiplexer;
High reflection fiber grating is positioned at the side near I section Transmission Fibers, is used to reflect the Rayleigh scattering light that is produced by I section Transmission Fibers;
Said demodulating system is used for demodulating I level DFB fiber laser surrounding environment physical quantity by said I level signal laser.
8. according to each described optical fiber sensing system in the claim 1 to 6, wherein, said environmental physics amount is pressure or temperature.
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| CN2012102700381A CN102818582A (en) | 2012-07-31 | 2012-07-31 | Optical fiber sensing system |
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| CN2012102700381A CN102818582A (en) | 2012-07-31 | 2012-07-31 | Optical fiber sensing system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106482863A (en) * | 2016-10-12 | 2017-03-08 | 山东省科学院激光研究所 | Temperature sensor and temperature-sensing system based on active phase-shifted grating |
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| US6018534A (en) * | 1998-07-13 | 2000-01-25 | E-Tek Dynamics, Inc. | Fiber bragg grating DFB-DBR interactive laser and related fiber laser sources |
| WO2002048654A1 (en) * | 2000-12-12 | 2002-06-20 | Optoplan As | Fibre optic sensor systems |
| CN1795628A (en) * | 2003-03-31 | 2006-06-28 | 法国电讯公司 | Optical device, especially for the suppression of a rayleigh double backscattered noise and system comprising said device |
| CN101572375A (en) * | 2009-04-30 | 2009-11-04 | 天津理工大学 | Device utilizing single longitudinal mode dual wavelength fibre laser to generate microwave and millimeter wave |
| CN101793570A (en) * | 2009-10-21 | 2010-08-04 | 南京大学 | Sensing method of optical-fiber Bragg grating laser device |
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2012
- 2012-07-31 CN CN2012102700381A patent/CN102818582A/en active Pending
Patent Citations (5)
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|---|---|---|---|---|
| US6018534A (en) * | 1998-07-13 | 2000-01-25 | E-Tek Dynamics, Inc. | Fiber bragg grating DFB-DBR interactive laser and related fiber laser sources |
| WO2002048654A1 (en) * | 2000-12-12 | 2002-06-20 | Optoplan As | Fibre optic sensor systems |
| CN1795628A (en) * | 2003-03-31 | 2006-06-28 | 法国电讯公司 | Optical device, especially for the suppression of a rayleigh double backscattered noise and system comprising said device |
| CN101572375A (en) * | 2009-04-30 | 2009-11-04 | 天津理工大学 | Device utilizing single longitudinal mode dual wavelength fibre laser to generate microwave and millimeter wave |
| CN101793570A (en) * | 2009-10-21 | 2010-08-04 | 南京大学 | Sensing method of optical-fiber Bragg grating laser device |
Non-Patent Citations (1)
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| 李东明等: "高灵敏度加速度抵消型分布反馈有源光纤光栅水听器研究", 《中国激光》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106482863A (en) * | 2016-10-12 | 2017-03-08 | 山东省科学院激光研究所 | Temperature sensor and temperature-sensing system based on active phase-shifted grating |
| CN106482863B (en) * | 2016-10-12 | 2019-02-01 | 山东省科学院激光研究所 | Temperature sensor and temperature-sensing system based on active phase-shifted grating |
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Application publication date: 20121212 |