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Theoretical And Experimental Study On Integrated Michelson-FP Composite Fiber Interferometer

Posted on:2016-09-30Degree:MasterType:Thesis
Country:ChinaCandidate:Z Z WangFull Text:PDF
GTID:2348330542476224Subject:Engineering
Abstract/Summary:PDF Full Text Request
Optical fiber sensors have developed rapidly and been widely used in many fields,including structural health monitoring,because they are highly sensitive,anti-electromagnetic,adapted to harsh environmental conditions and in small size.The future optical fiber sensors will be in all-fiber path,more integrated and can measure several parameters.The paper describes the present situation of fiber sensor integration and multi-parameter measurement,and also mentions some related structures.Michelson and Fabry-Perot(F-P)fiber interferometers are all interferometric fiber optic sensor devices.They have high precision and large dynamic range.Michelson interferometer made of two core fiber is sensitive to bending.F-P fiber interferometer is available to the measurement of strain.Based on the two interferometer structures,this paper presents an integrated Michelson-FP composite fiber interferometer,which can measure bending and strain simultaneously.According to working principles of the two fiber interferometers and two beam interference theories,the composite interference formula has been deduced.General Structures and theory basis of Michelson and F-P fiber interferometers are described in the paper.The composite interference is regarded as combinations of two lights.Two formula components sensitive to bending and strain respectively are chosen and emphasized.Structure of the integrated Michelson-FP composite fiber interferometer is put forward.Make Michelson interferometer with two core fiber firstly.Then splice quartz tube and single mode fiber behind the two core fiber orderly to fabricate F-P cavity structure.And the composite fiber interferometer is completed.Simulate and analyze the composite interference spectrum.Utilize fast Fourier transform(FFT)to get the composite interference spatial frequency spectrum.Identify frequencies of the chosen formula components,and extract their interference fringes by digital filter.To verify the composite fiber interferometer's sensing characteristic for multi-parameter measurement,three experiments about bending,strain and temperature are carried out.When crunch their experiments numbers,interference fringes of the two formula components are extracted from composite interference spectrum.Analysis and compare the two interference fringes' change trend.The results of data processing show that the two formula components are not cross sensitive to bending and strain,which proves that the composite fiber interferometer can be used in two-parameter measurement for bending and strain.
Keywords/Search Tags:Interferometric fiber optic sensor, Integrated fiber optic interferometer, Multi-parameter measurement, Two core fiber, FFT
PDF Full Text Request
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