Research And Design Of Curvature Sensor Based On Larhe Negative Dispersion Microstructure Fiber

A twist parameter is a very important parameter in rotating power machinery,and realtime and accurate detection of twist parameters is of great importance for the operation of machinery.However,existing distortion sensors,which measure physical quantities based on light intensity directly,are susceptible to be interfered by fluctuations in light sources or changes in the loss of the sensing system.Therefore,based on the mode coupling theory,this paper proposes a distortion sensor system and method based on the wavelength shift corresponding to the peak of the negative dispersion curve,that is,a distortion sensor system and method that directly measures the physical quantity as negative dispersion.The main content of this paper is as follows:Firstly,the background and research significance of optical fiber sensors and twist sensors are summarised,and the current research progress on optical fiber twist sensors at home and abroad is reviewed.The dispersion properties of microstructure fiber are briefly introduced,and some numerical research methods and theories used in this paper are briefly described;Secondly,the Cartesian coordinate system is converted to a spiral coordinate system to simulate the two-dimensional structure of microstructure fiber.Based on the coaxial dualcore structure,a dispersion compensation microstructure fiber is designed.Using the influence of twist on the properties of the optical fiber,the shift of wavelength corresponding to the peak of negative dispersion curve under different degrees of twist is studied,and a twist sensing system is designed to achieve the measurement of twist;Thirdly,a dispersion compensation microstructure fiber is designed based on the principle of multi-core coupling using the coupling between two different point-core structures.Using the influence of twist on the properties of optical fibers,the shift of wavelength corresponding to the peak of negative dispersion curve under different degrees of twist is studied,and a twist sensing system is designed to achieve the measurement of twist;Finally,birefringence is introduced into the fiber to reduce the symmetry of the fiber structure.the influence of birefringence properties on two types of twist sensors is studied when optical fibers are twisted,so as to study the shift of wavelength corresponding to the peak of negative dispersion curve at different degrees of twist,a highly sensitive twist sensor is designed.