The Simulation Research And Experiment On The Process Of Fine Polarization Maintaining Fiber Fused Biconical Tapering

With the rapid developing of optical fiber technique, polarization maintaining fibercoupler as the key component of FOG(fiber-optic gyroscope) is generally applied tonational defense and military field. Its performance and fabrication level seriouslyinfluence FOG’s performance. FBT(Fused Biconical Taper) technique is the mainmethod to fabricating polarization maintaining fiber coupler now. Based on the opticalwaveguides theory and thermal viscoelasticity theory, this paper conduct the simulationresearch and experiment on the process of polarization maintaining fiber with80mdiameter fused biconical tapering.Firstly, establish the fusion tapering geometry model of single polarizationmaintaining fiber. And base on the model establish the fusion tapering geometry modelof fused taper polarization maintaining fiber coupler. Then analyze the mechanism ofoptical wave propagating in fiber and energy coupling process between two fiber toresearch the influence of the process of fused biconical tapering on the performance ofpolarization maintaining fiber coupler. Use the Maxwell model to Fitting the thermalviscoelastic properties of optical fiber material based on the mechanical properties ofthe thermal viscoelastic material and its physical model. Then establish the constitutiveequation of optical fiber material on the basis of thermal rheology simple materialproperties.Secondly, use finite element simulation method analyze the process of single fiberfused tapering, including carrying out thermal analysis of preheating stage andthermal-structure coupling analysis of fused tapering stage. Determine the time ofpreheating stage through thermal analysis, and obtain the shape of deformation zone ofoptical fiber through thermal-structure coupling analysis. To obtain the thermalviscoelastic properties model of fused optical fiber material, do high temperature creepexperiments for silica glasses on the electronic universal material testing machine. Thentransfer the creep curves into shear modulus curves and fit the generalized Maxwellmodel parameter of the fiber material with the viscoelastic materials curve fittingfunctions of ANSYS. Measuring the temperature field distribution of the high voltagearc, determine the temperature condition of the process of fused biconical tapering.Finally, design the tensile force measurement device. And calibrate the relationship between the control voltage of electric magnetic force and the tensile force on opticalfiber to realize the control of tensile force. Conduct experiment on the fused taperingplatforms. Use a microscope to observe the microstructure of the fused taper fiber aftercompleting the experiments. And then measure the shape of optical fiber fusion area andthe forming quality to research the influence of tensile force and speed on the process offused biconical tapering.