Research On Optical Fiber Sensors Based On Microstructure Fiber Integrated With Nano Functional Material

Along with the arrival of information era and the fast development of internet of things,the high-speed data transformation such as photo-communication and optical interconnects are highly required.New materials,theories,plans and conceptions were continuous proposed to meet the requirement of all-fiber photonic integrated system for micronano photonic devices.Micronano waveguide technology combined with the physical effect of photoelectric functional materials for the research on beam propagation and control of the optical waveguide to achieve micronano photonic devices has become an important issue in the field of photonics.The microstructure fiber optic sensors employed in this thesis were based on several micronano optical fiber which have different microstructure that were used as sensitive part of the optical device.Due to the strong evanescent field which combined with nano functional materials,the microstructure fiber can interact with the outside environment so that the outside parameter can be detected directly.In this thesis,we customized the microstructure of optical fiber that with different transmission character through arc discharge method,and analyzed the transmission character of the fiber.The sensing character of the microfiber combined with nano functional materials have been analyzed through experimental and theoretical method.A series of high sensitivity,low temperature sensitive optic fiber sensor was achieved and possess a promised application prospect.The main content of this thesis includes:1.The fabrication of microstructure optical fiber through electric arc discharge method with a fiber splicer.The high-precision displacement platform employed in this experiment could control the parameters precisely which determined performance of the device,such as the length of the tapered range,the space between adjacent tapers.In addition,the fiber splicer could precisely adjust the diameter of the waist taper through controlling the fusion power and the fusion time.In this way,the micro taper with different parameters could be achieved.The tapered microstructure optical fiber evanescent field characteristics and mode energy distribution were featured through numerical calculation theoretical analyze.With the fiber diameter decrease,optical fiber energy will not be confined in the fiber core,a part of energy will leak into the cladding,transform to evanescent waves.The evanescent field will become stronger along with the decrease of diameter.Then the interaction with outside environment will be enhanced as well as the increase of sensing sensitivity to the change of outside environment.2.In this part,a kind of refractive index sensor based on single mode fiber with periodic tapers microstructure and a relative humidity sensor based on tapered square no-core fiber which coated with SiO2 nanoparticles have been proposed.The periodic tapers microstructure fiber and tapered square no-core fiber coated with SiO2 nanoparticles was customized through high precision moving platform and fiber splicer with adjusted discharge parameters.The sensing mechanism of these two kinds of sensors were investigated as well as the effective theoretical model was constructed.Furthermore,we analyzed the sensing mechanism of these two fiber optic sensors and investigated the interference peak wavelength of these two sensors tuned by environment refractive index and relative humidity respectively.3.Two kinds of magnetic field sensors based on the microstructure all solid waveguide array fiber were proposed and realized.The taper and periodic tapers microstructures were made by the fiber splicer,and integrated with the magnetic fluid nanomaterials,these two magnetic sensors were capable of high sensitivity measurement of outside magnetic field..The mode coupling and interference characteristics of these two kinds of micro structure fibers were carried out through theoretical analysis and simulation.Further investigation and specific analysis of the interference peak intensity and the amplitude changing with outside magnetic field of these two kinds of magnetic field sensors were carried out respectively.