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Research On SPR Micro-displacement Sensing Mechanism Based On Graded-index Multimode Fiber

Posted on:2018-09-16Degree:MasterType:Thesis
Country:ChinaCandidate:Y S WangFull Text:PDF
GTID:2348330542990884Subject:Engineering
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The sensing function can be realized,and a variety of environmental parameters can be measured by combining surface plasmon resonance technology with optical fiber technology.In this paper,a micro-displacement sensing structure of the graded-index multimode fiber based on the SPR sensing technology is designed and optimized.The micro-displacement sensing structure of graded-index multimode fiber is based on SPR sensing technology.The principle is when the light is put into the graded-index multimode fiber,the light transmission path changes with the micro-displacement injection position of the single fiber.Then SPR incident angle changes,and the output light field changes.Finally the micro-displacement sensing function is realized.The main researches are as follows: the light transmitting-field of the graded-index multimode fiber is simulated in Rsoft software.Simulation results show the light trace transmits with sine and cosine form,and sensitive to the micro-displacement injection position of the single fiber,which is consistent with the theory.In order to make the SPR phenomena appears easily,the graded-index multimode fiber with corroded sensing zone is came up with to be applied into micro-displacement sensing structure,and the light transmitting-field is simulated in Rsoft software.Compared with the simulating results of the light transmitting-field of the graded-index multimode fiber,when the injection position deviation is small,the SPR phenomenon appears easily using graded-index multimode fiber with corroded sensing zone.The light transmitting-field of graded-index multimode fiber and graded-index multimode fiber with corroded sensing zone is observed in experiments.Experimental results show that the SPR phenomenon appears easily using graded-index multimode fiber with corroded sensing zone,which is beneficial to the design of sensing structure.A micro-displacement sensing structure using graded-index multimode fiber with corroded sensing zone based on SPR sensing technology is designed,and experiments are performed.Experimental results show that when the injection position of the single fiber moves,the SPR spectral line resonance valley changes regularly,and sensing of the micro-displacement is realized.The sensing structure is with sensing range 6?m,linearity 2%,and sensitivity3.75nm/?m.The influence of numerical aperture on the performance of the sensing structure is investigated.When the ambient liquid refractive index is fixed at 1.33,the sensor experiments are carried out under the condition of the numerical aperture of 0.14 and 0.3,respectively.Experimental results show that the higher the numerical aperture is,the higher the sensitivity,linearity and sensing range are,and the better the sensing performance is.The effect of ambient liquid refractive index on the performance of sensing structure is investigated.The sensing experiments are carried out under the condition of liquid refractive index of 1.34,1.35,1.36 and 1.37,respectively.Experimental results show that the refractive index of ambient liquid has little influence on the sensing performance.Considering that the liquid environment of sensing zone leads to poor stability of sensing structure,the sensing structure is difficult to be applied in practice.We proposes micro-displacement sensor using special-fiber whose core is coated by gold film.The environment of sensing zone is solid instead of liquid,which makes it easier to integrate and encapsulate the sensor structure.The proposed micro-displacement sensor using special-fiber whose core is coated by gold film effectively improves the practicability.
Keywords/Search Tags:surface plasmon resonance, micro-displacement sensor, graded-index multimode fiber
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