Distributed fiber-optic the characteristic that passes feeling technology and research current situation

Keywords: 　 of Brillouin Effect of 　 of 　 of Raman Effect of 　 of 　 of OTDR of 　 of 　 of Distributed Optical Fiber Sensing Technology is distributed fiber-optic passing feeling technology put forward in 70 time end, it is as very extensive smooth time domain still applies to reflex in fiber-optic now project (OTDR) technical occurrence and development rises. In these ten years, arose a series of distributed fiber-optic pass feeling mechanism and survey a system, be able to apply stage by stage in many domains. Current, this technology already was become fiber-optic one of technologies that the prospect provides most in passing feeling technology. 1 distributed fiber-optic the characteristic that passes feeling technology is distributed fiber-optic pass feeling technology to have get at the same time passing what change along with time and space inside sensitive fine area to be measured to distributing the ability of information, its are basic the feature is [1] : ① is distributed fiber-optic pass feeling system to pass feeling component mediumly to be only fiber-optic; ② is measured can get the one dimension that is measured inside whole and fiber-optic area to distributing graph, will fiber-optic erect becomes grating state, the 2 peace keeping that can determine to be measured are three-dimensional distributinging circumstance; The dimensional resolution of ③ system is in commonly the volume level of rice, be in to be being measured consequently narrower the change of limits is general can observation its average; The measurement of ④ system precision and dimensional resolution exist to restrict a relation each other commonly; ⑤ detects signal is common fainter, consequently requirement signal processing system has taller letter a confusion of voices to compare; Because ⑥ is detecting need to undertake many signal addition in the process the scanning of average, frequency, phasic dog wait for processing, realize complete measurement to need longer time consequently. 2 distributed fiber-optic pass feeling technology to study the current situation is distributed fiber-optic once appear,pass feeling technology, got wide attention and thorough research, and be in ten short years got flying development. According to the property of signal, this kinds pass feeling technology to be able to divide it is 4 kinds: ① is used backward of Rayleigh scattering pass feeling technology; ② uses La graceful effect pass feeling technology; ③ uses effect of the deep in cloth pass feeling technology; ④ is used forward of transmission model coupling pass feeling technology. 2.

1 use backward of Rayleigh scattering distributed fiber-optic the microcosmic particle in incident light and medium happens stretch collision place to cause pass scattering of feeling technology Rayleigh, the frequency of the frequency of scattering light and incident light is same. Using backward of Rayleigh scattering fiber-optic in passing feeling technology, use smooth time domain to reflex commonly (OTDR) the dimensional fixed position that the structure will come to come true to be measured, the structure of typical sensor is shown 1 times like the graph. Light of basis Rayleigh scattering is in fiber-optic in the modulation action that get, should pass feeling technology to be able to be divided for intensity modulation model with the polarization voice modulation graph 1 backward scattering distributed fiber-optic sensor is basic systematic block diagram 2.

1.

1 intensity modulation [2] 　 is in when light of a bundle of pulse fiber-optic in when transmission, as a result of fiber-optic in those who be put in refractive index is microcosmic inhomogenous sex, can produce Rayleigh scattering. If the change of outside physical quantity can cause the change of character of fiber-optic absorption, loss or Rayleigh scattering coefficient, so through detecting backward the bulk that the intensity of scattering smooth signal can acquire outside physical quantity. Be based on at present right backward the sensor that Rayleigh scattering light undertakes intensity modulation is advantageous material of fine of consumed of the distributed fiber-optic force transducer that forms with small curved loss, benefit is below radiation illuminate the distributed radiate sensor that causes smooth loss to form, the distributed chemical sensor that benefit chemically dye makes to absorbing character solely, use the distributed temperature sensor that the relation of coefficient of fiber-optic Rayleigh scattering and temperature forms fluid core. 2.

1.

Bounce technique of smooth time-domain of condition of modulation of 2 polarizations condition polarization (POTDR) put forward by Rogers[3] at first, its fundamental is, if fiber-optic the modulation that gets physical quantity of a few outsides, voice meets so smooth polarization produce change subsequently, and the polarization that Rayleigh scattering light nods in scattering direction and incident light are same, be opposite in fiber-optic incident end so backward voice mixes the polarization of Rayleigh scattering light the distributinging case that the defer time of smooth signal has detecting can acquisition outside physical quantity. Can be opposite as a result of magnetic field, electric field, transverse pressure and temperature fiber-optic in voice undertakes smooth polarization modulation, accordingly this technology can use at realizing many physical quantity measure. Be based on backward of Rayleigh scattering passing feeling technology is contemporary distributed fiber-optic the foundation that passes feeling technology, it got extensive development in 80 time initial stage. Because this technology is overcome hard,measure precision however low, pass the defect with feeling short distance, the research in this respect is at present little already have a story. 2.

2 use those who play graceful effect is distributed fiber-optic pass feeling technology 2.

2.

1 use initiative Raman the distributed temperature of scattering passes feeling technology light to pass fiber-optic when, photon and fiber-optic medium smooth phonon can arise inelastic collision, produce La graceful scattering, wavelengh is Situokesiguang at incident light greatly, wavelengh is less than incident light to turn over Situokesiguang. Situokesiguang and the strength that combat Situokesiguang compare and the concern of temperature can indicate by next type: 　 of 　 of 　 of 　 of 　 of A)4exp(-hcu/KT) of λ of R(T)=(λ S/ (the H in 1) type - Pulangke is invariable; C - vacuum velocity of light; K - Boerciman is invariable; T - absolutely temperature. Consequently this one relation and technology of reflex of smooth time domain are united in wedlock to be able to make distributed temperature sensor. Graph the 2 basic structure block diagram that are this kinds of sensor. Use the inherent loss with Situokesiguang and the more fiber-optic than can be being eliminated strength that combat Situokesiguang and the influence that inhomogenous sex brings. Graph it is distributed that the block diagram of 2 principle of sensor of distributed fiber-optic temperature that are based on initiative La graceful scattering are based on the distributed temperature that pulls graceful scattering to pass feeling technology fiber-optic a most mature technology in passing feeling technology. The basically has England King university that begins research work to this technology [4] , chongqing university of China [5] and Chinese metric institute [6] . Current, a few products of this kinds of sensor already appeared in international, home market, most famous is the DTS80 of British York company, its dimensional resolution and temperature resolution can achieve 1m, 1 ℃ respectively, measure limits to be 4 ～ 8km. 2.

2.

2 use suffer stimulating the distributed stress that plays graceful effect to pass feeling technology to should pass feeling technology is put forward by Farries and Rogers[7] at first. Be in send sensitive a rope for towing a boat the Nd:Y of two endAG laser and He-Ne laser give out one wavelengh to be 617nm pulse to be mixed solely respectively one wavelengh is 633nm successive wave. Because two bundles of smooth difference on the frequency are in La inside the gain chart of graceful enlarge, the effect that suffers pulse light solely continuously with Lamanzeng beneficial magnifies. Because beneficial is opposite Lamanzeng pulse light and the polarization of exploration light voice is extremely sensitive, and two bundles of smooth polarizations voice can by fiber-optic the modulation of transverse stress place that go up, because this uses the intensity of successive light and light,be in fiber-optic medium transmission time can obtain transverse stress to be in fiber-optic go up distributing. 2.

3 those who use effect of the deep in cloth is distributed fiber-optic pass feeling technology 2.

3.

The 1 distributed fiber-optic temperature that uses scattering of the deep in initiative cloth, meet an emergency passes feeling technology light to pass fiber-optic when, photon and fiber-optic in because give out heat oneself,the phonon that move and arises can arise inelastic collision, produce scattering of the deep in initiative cloth. The frequency of scattering light produces change relative to the frequency of incident light, the size of this one change and scattering angle and fiber-optic material character are concerned. The fiber-optic material character related as smooth as scattering of the deep in cloth frequency basically suffers the effect of temperature and meet an emergency, accordingly, through determining of pulse light backward the frequency of light of scattering of the deep in cloth moves to be able to realize distributed temperature, meet an emergency to measure. The distributed sensor that the person such as Tkach put forward a kind to be based on this principle 1989 [8] . The person such as Parker observes at passing a test 1997 the power with temperature, meet an emergency and smooth scattering of initiative cloth Li Yuan exists respectively, inverse proportion concerns, the experimental result that moves to become direct ratio with the change of temperature and meet an emergency according to the frequency of light of scattering of the deep in cloth and put forward, the coupling equation that adopts change of the power that seek solution and frequency change can realize the temperature on Chan Genguang fine and meet an emergency to be measured at the same time [9] . 2.

3.

2 use the distributed temperature that suffers effect of the Li Yuan that stimulate cloth, meet an emergency to pass feeling technology this technology is offerred by the Horiguchi[10] of Japanese NTT at first, because it is measured in temperature, meet an emergency,go up the measurement that can achieve precision, pass feeling length and other of dimensional resolution prep above to pass feeling technology, get wide attention and research at present. The typical structure of the sensor that is based on this technology is structure of amplifier of the deep in cloth, if pursue,3 are shown. Be in fiber-optic of two end adjustable humorous laser parts to send infuse of one pulse light and light of in succession add sensitive a rope for towing a boat, when two bundles smooth difference on the frequency is in encounter inside bandwidth of gain of the deep in the cloth in fiber-optic area when, two bundles of light can nod effect of amplifier of the deep in generation cloth in action, mutual produce energy move. While the frequency to two bundles of laser undertakes be adjustmented continuously, the power of the successive light that shoots from fiber-optic one aspect of the matter through detecting, can decide fiber-optic Li Yuan gain achieves the cloth on paragraphs of each are small area the biggest when the difference on the frequency of place correspondence. Decides difference on the frequency and fiber-optic go up the cloth Li Yuanpin on each paragraphs of area moves equal, because this is in fiber-optic go up to move to decide subsequently into the temperature of direct ratio and meet an emergency with cloth Li Yuanpin. The harmonious precision that should pass what feeling technology can achieve to measure precision to basically rely on two laser. Graph 3 be based on the block diagram of distributed fiber-optic sensor that suffers effect of deep of the city that stimulate cloth to become the frequency prep above of pulse light is successive when smooth frequency, the energy of pulse light is transferred to successive light, this kind passes feeling means to call gain of the deep in cloth model; The frequency when pulse light when the frequency under successive light, the energy of successive light is transferred to pulse light, this kind passes feeling means to call loss of the deep in cloth model. When fiber-optic the temperature that go up or meet an emergency are when distributinging equably, what gain of the deep in cloth passes feeling means to be able to cause pulse light energy is quick reduce, achieve long distance hard thereby detect; What loss of the deep in cloth passes feeling means to cause pulse light energy is elevatory, can achieve long distance thereby detect. The means that the person such as Canadian Bao Xiaoyi uses loss of the deep in cloth came true to be as long as of 51km pass feeling length, came true in the near future 0.

The dimensional resolution of 5m [11] . What German Garus also put forward a kind to be based on frequency region to analyse a way is new-style distributed fiber-optic pass feeling technology [12] , it uses what immigrate of frequency of the deep in cloth realizes temperature and meet an emergency to pass likewise feeling, but the bounce technique of smooth time domain that the convention did not use when the space that is measured in implementation locates, used the spectrum character that suffers scattering of the Li Yuan that stimulate cloth however. 2.

4 those who use transmission model coupling is distributed pass feeling technology the common form of this sensor is, smooth incident do not be in fiber-optic two end with exploration cent. If pass sensitive fine to support two kinds of of different transmission speed transmission standards, so fall in the action of certain outside ambient, this fiber-optic asking for the one part energy of transmission model arrives with respect to meeting coupling another transmission model. Because this is in,the intensity of the coupling model that fiber-optic other one aspect of the matter exports can reflect a volume that is measured, the defer time between two transmission models reflects the position that gives coupling point. Frank measures one birefraction at using method of frequency modulation carrier wave 1986 fiber-optic on of transverse stress distributing [13] . What Katrotsios uses interferometer of Michael Er abdicate at putting forward a kind 1987 is phasic survey plan [14] . Should pass feeling technology to be in theoretic extremely attainable high dimensional resolution, but put in very great difficulty on implementation. 3 distributed fiber-optic because the application that sends feeling technology and development are distributed fiber-optic pass feeling technology to be able to realize big range to measure the extraction that information distributings in field, consequently it can solve the numerous difficult problem that measures a domain at present, be like: The temperature that distributed temperature sensor can use at big, medium-sized transformer, generation set and wildcat distributings measure, the fire of building of large storehouse, oil depot, high level, mine and channel defends reach call the police the domain such as the system; Distributed stress sensor can be used at the safety of the establishment such as bridge, dikes and dams to detect, of the degree of large facility ageing such as aircraft of aviation, spaceflight detect, the domain such as intelligent data preparation. However, to realize the fast, stable, measurement that reachs high accuracy reliably, still need to have the research of many sided. The research henceforth basically also will put in the following respects mainly: ① realizes parameter of on Chan Genguang fine many physics (temperature and meet an emergency) or chemical parameter while measure; ② raises signal to receive with processing system detect ability, improve dimensional resolution of the system and uncertainty of measurement; ③ raises those who survey a system to measure range, decrease measure time; ④ conducts the research of feeling mechanism newly. CNC Milling CNC Machining