CN102818657A - Long-distance distributed Raman temperature sensor based on erbium-doped optical fiber amplifier (EDFA) amplification technology - Google Patents
Long-distance distributed Raman temperature sensor based on erbium-doped optical fiber amplifier (EDFA) amplification technology Download PDFInfo
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- CN102818657A CN102818657A CN2012103262844A CN201210326284A CN102818657A CN 102818657 A CN102818657 A CN 102818657A CN 2012103262844 A CN2012103262844 A CN 2012103262844A CN 201210326284 A CN201210326284 A CN 201210326284A CN 102818657 A CN102818657 A CN 102818657A
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Abstract
The invention relates to a temperature sensor, in particular to a long-distance distributed Raman temperature sensor based on an erbium-doped optical fiber amplifier (EDFA) amplification technology. The long-distance distributed Raman temperature sensor is characterized by being provided with at least two sensing optical fibers, wherein two circulators and an amplifier are arranged between the two adjacent sensing optical fibers. A signal in a previous-stage sensing optical fiber sequentially passes through a first circulator, the EDFA amplifier and a second circulator to enter a next-stage sensing optical fiber, and an reverse direction reflecting signal in the next-stage sensing optical fiber sequentially passes through the second circulator and the first circulator, then returns to the previous-stage sensing optical fiber and is sent to a data acquirer through a wavelength division multiplexer. Compared with the prior art, secondary amplification process is performed to a laser pulse signal in the temperature measuring process by adding the EDFA amplifier, and a temperature measuring distance of the distributed Raman temperature sensor can be effectively prolonged.
Description
Technical field
The present invention relates to temperature sensor, a kind of specifically long-distance distribution formula Raman temperature sensor based on the EDFA amplifying technique that can effectively improve thermometric distance and thermometric accuracy.
Background technology
As everyone knows; The distributed Raman temperature sensor is compared with traditional point temperature sensor owing to can realize distributed temperature survey, under the application of temperature field measurement remarkable advantages is arranged on a large scale; Thereby the market demand rises year by year, becomes the focus of current research.
The structure of traditional distributed Raman temperature sensor such as accompanying drawing 1; Its principle of work is that the pulse of pulsed laser emitted laser gets into sensor fibre through wavelength division multiplexer; Pulsed laser signal and optical fiber interact; Produce Raman scattering signal dorsad, comprise stokes light and anti-Stokes light in the Raman scattering signal dorsad, its Wavelength distribution is as shown in Figure 2.Stokes light and anti-Stokes light turn back to wavelength division multiplexer along sensor fibre, send into data acquisition unit after being separated by wavelength division multiplexer, and the data acquisition unit collection also calculates stokes light and the light intensity of anti-Stokes light.Because the strength ratio of stokes light and anti-Stokes light is relevant with the temperature of optical fiber, the temperature that the Stokes light intensity that therefore collects according to collector and anti-Stokes light intensity just can calculate sensor fibre, further analysis acquisition temperature information.
But since dorsad the Raman scattering signal very a little less than; And because laser is when transmitting in the optical fiber lossy (shown in accompanying drawing 3); So the signal of Raman scattering dorsad that the sensor fibre end returns very a little less than; Two kinds of light signals are seen Fig. 4 with the situation of the increase loss of distance, and then cause traditional distributed Raman temperature sensor signal to noise ratio (S/N ratio) in the thermometric process of medium and long distance very poor, and the sensor fibre terminal temperature fluctuation degree that calculates is very big; Thermometric is inaccurate, has seriously limited to the popularization of optical fiber temperature-measurement technology.
In order to realize the application of distributed Raman temperature sensor in medium and long distance thermometric process; Be through strengthening the peak-power of laser pulse of pulsed laser output in the prior art; Thereby strengthen Raman scattering signal dorsad; To reach the intensity that promotes the signal of Raman scattering dorsad that the sensor fibre end returns, the purpose that realizes longer measuring distance; But along with peak-power of laser pulse strengthens gradually, nonlinear effect will appear in the Raman scattering signal dorsad, and just can't continue to use Stokes light intensity and anti-Stokes light intensity to carry out temperature survey in case nonlinear effect occurs.Therefore the measuring distance of existing Raman temperature sensor generally is no more than 10km, and the longest distributed optical fiber Raman temperature sensor of measuring distance by the end of on August 31st, 2012 through the GB/T21197-2007 standard test is 10km.
Summary of the invention
The present invention is directed to the shortcoming and defect that exists in the prior art, propose a kind of rational in infrastructure, long-distance distribution formula Raman temperature sensor that can effectively promote thermometric distance and thermometric accuracy.
The present invention can reach through following measure:
A kind of long-distance distribution formula Raman temperature sensor based on the EDFA amplifying technique; Comprise the pulsed laser that output terminal is connected with the input end of wavelength division multiplexer, the wavelength division multiplexer that output terminal is connected with sensor fibre, the data acquisition unit and the sensor fibre that are used to gather back-reflection light signal in the sensor fibre that is connected with wavelength division multiplexer; It is characterized in that being provided with at least two sensor fibres; Be provided with two circulators and EDFA amplifier between two adjacent sensor fibres; Wherein through getting into the next stage sensor fibre behind first circulator, EDFA amplifier, second circulator, the back-reflection signal in the next stage sensor fibre returns the upper level sensor fibre and sends into data acquisition unit through wavelength division multiplexer the signal in the upper level sensor fibre successively behind second circulator, first circulator successively.
The upper level sensor fibre is meant in two adjacent sensor fibres one near wavelength division multiplexer among the present invention; Circulator among the present invention is three port organizations; Wherein the front end of the end of upper level sensor fibre and next stage sensor fibre is connected with the port one of first circulator, the port one of second circulator respectively; The port three of first circulator is connected with the port two of second circulator, and the EDFA amplifier input terminal is connected with the port two of first circulator, and output terminal is connected with the port three of second circulator; Pass through port one, port two outgoing of circulator behind the laser pulse signal process upper level sensor fibre successively; Get into the EDFA amplifier, through getting into from the port three of second circulator again after the processing and amplifying, and arrive the next stage sensor fibre from the port one of second circulator.
The present invention can increase the quantity of EDFA amplifier between adjacent two sensor fibres according to the distance of measuring distance, increases the intensity of light signal, reduces the loss of long-distance transmissions to signal.
The present invention in use; When laser pulse through behind the upper level sensor fibre, peak-power of laser pulse since loss a little less than, this moment, more weak laser pulse got into the EDFA amplifier through first circulator; The EDFA amplifier carries out a light amplification with laser pulse; Improve its peak power, laser pulse gets into the next stage sensor fibre more then, and the Raman scattering signal that laser pulse produces in the upper level sensor fibre turns back to wavelength division multiplexer by the upper level sensor fibre; The signal of Raman scattering dorsad that laser pulse produces in the next stage sensor fibre gets into first circulator through second circulator; Turn back to wavelength division multiplexer through the upper level sensor fibre then; Through implementing checking, the present invention proposes can obviously improve based on the distributed Raman temperature sensor of EDFA amplifying technique the accuracy of measurement and the thermometric distance of distributed Raman temperature sensor.
Description of drawings:
Accompanying drawing 1 is the structural representation of distributed Raman temperature sensor in the prior art.
Accompanying drawing 2 is that laser transmits the backscatter signals wavelength coverage distribution plan that produces in optical fiber.
Accompanying drawing 3 is light loss synoptic diagram in optical fiber of different wave length.
Accompanying drawing 4 stokes lights and anti-Stokes light intensity are with the die-away curve of distance.
Accompanying drawing 5 is structural representations of the present invention.
Accompanying drawing 6 is a kind of example structure synoptic diagram of the present invention.
Reference numeral: pulsed laser 1, wavelength division multiplexer 2, upper level sensor fibre 3, data acquisition unit 4, EDFA amplifier 5, next stage sensor fibre 6, first circulator 7, second circulator 8.
Embodiment:
Below in conjunction with accompanying drawing and embodiment the present invention is further described.
Can't realize the problem of long range measurements in order to overcome existing distributed formula Raman temperature sensor; The present invention has used structure shown in Figure 5; Comprise the pulsed laser 1 that output terminal is connected with wavelength division multiplexer 2, the wavelength division multiplexer 2 that output terminal is connected with sensor fibre, the data acquisition unit 4 and the sensor fibre 3 that are used to gather back-reflection light signal in the sensor fibre that is connected with wavelength division multiplexer 2; Wherein be provided with two sensor fibres at least; Be provided with two circulators and EDFA amplifier 5 between two adjacent sensor fibres; Signal in the upper level sensor fibre 3 gets into next stage sensor fibres 6 through first circulator 7, EDFA amplifier 5, second circulator, 8 backs successively, and the back-reflection signal in the next stage sensor fibre 6 returns upper level sensor fibre 3 and after wavelength division multiplexer 2 is handled, sends into data acquisition unit 4 behind second circulator 8, first circulator 7 successively.
The present invention can obviously improve the accuracy of measurement and the thermometric distance of distributed Raman temperature sensor, is described further below in conjunction with embodiment:
Embodiment:
A kind of distributed Raman temperature sensor based on the EDFA amplifying technique shown in accompanying drawing 6, is provided with two sensor fibres, has wherein added 2 circulators and 1 EDFA amplifier between the front end of the end of upper level sensor fibre 3 and next stage sensor fibre 6.
After laser pulse is through upper level sensor fibre 3; Peak-power of laser pulse since loss a little less than; This moment, more weak laser pulse got into EDFA amplifier 5 through first circulator 7, and EDFA amplifier 5 carries out a light amplification with laser pulse, improves its peak power; Laser pulse gets into next stage sensor fibre 6 more then, and the Raman scattering signal that laser pulse produces in upper level sensor fibre 3 turns back to wavelength division multiplexer 2 by upper level sensor fibre 3; The signal of Raman scattering dorsad that laser pulse produces in next stage sensor fibre 6 gets into first circulator 7 through second circulator 8; Turn back to through upper level sensor fibre 3 then and carry out subsequent treatment in the wavelength division multiplexer 2, can use through this structure of actual test measuring distance is prolonged about 50%.
The present invention compared with prior art carries out the secondary processing and amplifying through adding the EDFA amplifier to the laser pulse signal in the thermometric process, can effectively improve the thermometric distance of distributed Raman temperature sensor.
Claims (3)
1. long-distance distribution formula Raman temperature sensor based on the EDFA amplifying technique; Comprise the pulsed laser that output terminal is connected with wavelength division multiplexer, the wavelength division multiplexer that output terminal is connected with sensor fibre, the data acquisition unit and the sensor fibre that are used to gather back-reflection light signal in the sensor fibre that is connected with wavelength division multiplexer; It is characterized in that being provided with at least two sensor fibres; Be provided with two circulators and amplifier between two adjacent sensor fibres; Wherein through getting into the next stage sensor fibre behind first circulator, EDFA amplifier, second circulator, the back-reflection signal in the next stage sensor fibre returns the upper level sensor fibre and sends into data acquisition unit through wavelength division multiplexer the signal in the upper level sensor fibre successively behind second circulator, first circulator successively.
2. the long-distance distribution formula Raman temperature sensor based on the EDFA amplifying technique according to claim 1 is characterized in that in two adjacent sensor fibres of upper level sense light delicate fingers one near wavelength division multiplexer.
3. the long-distance distribution formula Raman temperature sensor based on the EDFA amplifying technique according to claim 2; It is characterized in that being provided with two sensor fibres; The front end of the end of upper level sensor fibre and next stage sensor fibre is connected with the port one of first circulator, the port one of second circulator respectively; The port three of first circulator is connected with the port two of second circulator; The EDFA amplifier input terminal is connected with the port two of first circulator, and output terminal is connected with the port three of second circulator.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104614091A (en) * | 2015-02-05 | 2015-05-13 | 中国科学院合肥物质科学研究院 | All-fiber long-distance high-spatial-resolution single-photon temperature sensor |
| CN108204858A (en) * | 2016-12-16 | 2018-06-26 | 中国石油天然气股份有限公司 | Vibration signal detecting system and detection method |
Citations (1)
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| CN102072741A (en) * | 2010-10-29 | 2011-05-25 | 上海华魏光纤传感技术有限公司 | Ultra-long distance distribution type optical fiber sensor and using method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102072741A (en) * | 2010-10-29 | 2011-05-25 | 上海华魏光纤传感技术有限公司 | Ultra-long distance distribution type optical fiber sensor and using method thereof |
Non-Patent Citations (1)
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| 杨斌 等: "新型超远程分布式光纤拉曼温度传感器", 《光通信研究》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104614091A (en) * | 2015-02-05 | 2015-05-13 | 中国科学院合肥物质科学研究院 | All-fiber long-distance high-spatial-resolution single-photon temperature sensor |
| CN108204858A (en) * | 2016-12-16 | 2018-06-26 | 中国石油天然气股份有限公司 | Vibration signal detecting system and detection method |
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