Research On Fused Taper Microfiber Bend Sensing

In this paper,a kind of multi-mode microfiber bending sensor was proposed,which was made by flame-heated fiber drawing method.In the experiment,the influence of setting parameters on the parameters of microfiber was studied.The simple supported beam structure and cantilever structure were constructed to realize the research of optical fiber bending sensor,and the microfiber bending sensors were prepared under different conditions were compared to explore the bending sensing characteristics.The main research contents are as follows.The characteristics of the optical fiber and microfiber structure were described in detail.Theoretical analysis of the transmission principle of light in the singlemode-multimode-singlemode fiber structure and the transmission principle of light in the microfiber and used the beam propagation method to simulate and analyze the transmission characteristics of light in singlemode-multimode-singlemode fiber structure and singlemode-microfiber-singlemode structure,to explore the transmission characteristics of microfiber.In this paper,microfiber were prepared by fused taper method single-mode fiber,50 multi-mode fiber,62.5 multi-mode optical fiber and 105 multi-mode optical fiber were selected for experiments.The control variable method was used to fabricate different types of optical fibers into microfibers.The microfiber was placed under CCD electronic magnifying glass for data monitoring,and the influence of preparation parameters of flame-heated fiber drawing method on the parameters of microfiber was explored.The sensing characteristics of multi-mode microfiber were explored,and the real-time monitoring method was used to detect the output spectrum of microfiber under different taper coefficients.The optimal parameters of microfiber were selected through the spectrum,and the next sensing experiment was carried out.The microfiber bending sensor with cantilever structure can obtain a larger and more coherent curvature measurement range.By setting the initial length of optical fiber 1.5cm,2.0cm and3.0cm,the influence of the initial length of optical fiber on the bending sensor was observed.Then the initial length of the fiber was fixed,and the influence of different stretching length on the microfiber bending sensing was studied.Finally,the microfiber bending sensor with initial fiber length of 1.5cm and stretching length of 7104?m was obtained.The bending sensing sensitivity is-3.885nm/m^-1,which can measure0-5.556m^-1 and larger curvature range.The whole measurement range is coherently,and the spectrum shows a stable trend.From the experimental results,it can be seen that in the bending sensing experiment of microfiber,the main influence on the sensing sensitivity of microfiber is the tensile length of microfiber,and with the tensile length of microfiber increasing gradually,it has little relationship with the initial length.