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Research On Inter-mode Interferometric Microstructured Fiber Optic Sensors Based On No-core Fiber

Posted on:2022-11-19Degree:MasterType:Thesis
Country:ChinaCandidate:Y M ZhaoFull Text:PDF
GTID:2518306743974749Subject:Information and Communication Engineering
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In recent years,fiber optic sensors have received a great deal of attention due to their high sensitivity,corrosion resistance and resistance to electromagnetic interference.Mach Zehnder Interferometer sensors(MZI)are used in various sensing applications due to their high sensitivity and simple construction.Increasingly,new structures such as biased core,bent,coated,corroded and tapered MZI sensors are being used to measure different parameters such as temperature,humidity,refractive index,liquid level and strain.A no-core optical fiber(NCF)is a special fiber without a core,which is used in sensing experiments to obtain high sensitivity by using its own cladding as the core and the external environment as the cladding for the sensing process.In this paper,three types of interferometric optical fiber sensors have been fabricated using the inter-modal interference principle to investigate the refractive index,temperature and refractive index properties of coreless optical fibers.The main studies in this paper are as follows.1.A Mach-Zehnder interferometer sensor based on a tapered NCF is designed,and the sensing structure and its fabrication method are introduced.Simulations of the energy spectrum and transmission spectrum of this structure were carried out using the Beam PROP module in the Rsoft optical waveguide simulation software,and a comparison of the transmission spectrum of the structure with and without a taper is given.The sensor is more sensitive to refractive index due to the multimode interference of the single-mode fiber(SMF)-NCF-SMF structure and the higher order modes excited by the tapered structure.The refractive index sensitivities are 130.5 nm/RIU from 1.340 to 1.380,330.0 nm/RIU from 1.380 to 1.420 and 906.0 nm/RIU from 1.420 to 1.440.The temperature sensitivity from 30 °C to 90 °C is 0.0595 nm/°C.The sensor is simple in structure,low in cost,and can be widely used for biosensing.2.A Mach-Zehnder interferometer sensor based on NCF with a biconical structure was designed and the sensing structure and its fabrication method were introduced.The simulations of the energy spectrum and transmission spectrum of the structure were carried out using the Beam PROP module of Rsoft optical waveguide simulation software,and the comparison of the transmission spectrum of the double-cone,singlecone and no-cone structures was given.The multimode coupling effect of the biconical structure makes the NCF more sensitive to the refractive index.The refractive index sensitivities of the structure are 159.56 nm/RIU,369.64 nm/RIU and 1013.56 nm/RIU in the ranges 1.34-1.38,1.38-1.42 and 1.42-1.44,respectively.The temperature sensitivity of the proposed structure is 0.0404 nm/°C in the range 30°C to 90°C.The proposed sensing structure is easy to fabricate,has a high refractive index sensitivity and has a promising future in the biological and medical fields.3.A Mach-Zehnder interferometer biosensor based on graphene oxide and glucose oxidase composite membrane(GO-GOD)was designed for measurement of glucose concentration and temperature,and the sensing structure and its fabrication method were presented.The simulations of the energy spectrum and transmission spectrum of the structure were carried out using the Beam PROP module of the Rsoft optical waveguide simulation software,and a comparison of the transmission spectrum before and after coating is given.The sensor is more sensitive to glucose concentration due to the multimode interference(MMI)of the SMF-NCF-SMF structure and the catalytic effect of the composite film.The sensitivities of the proposed sensor are 0.0321 nm/(g/L)and 0.0401 nm/(g/L)for glucose concentration from 10 g/L to 70 g/L,respectively,and0.0513 nm/°C,0.0326 nm/°C for temperature sensitivities from 10 °C to 70 °C.The sensor has a simple structure and low cost,and can be widely used for biosensing.
Keywords/Search Tags:Interference optical fiber sensor, Inter-mode interference, No-core fiber, Tapered structure, Glucose oxidas
PDF Full Text Request
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