Research On Numerical Simulation And Experiment Of Forming Progress For Fused Biconical Taper Optical Fiber

With development and wide application of optical fiber technology in aerospace, satellite,guided weapon, medical, communications and other fields, it is urgent to improve the efficiency of information transmission. Thus the All Optical Network (AON) and the Fiber to the Premise (FTTP), based on techniques of wavelength division multiplexing (WDM),frequency division multiplexing (FDM), time division multiplexing (TDM), are of great significance. Since the development and realization of the techniques above depend on the optical fiber coupler with the function of optical processing including optical transmission,coupling, splitting and interference, optical fiber coupler is an indispensable optical passive device. The fused tapered fiber coupler is the most popular and is widely used in the development and fabrication of optical components.The paper aims to study the fused stretching forming process of fused biconical fiber components in the aspect of manufacturing. Increased predictive accuracy would assist in component design, condition monitoring, and retirement strategy decisions. Based on the analysis of the viscoelasticity of optical fiber materials, the viscoelasticity was described by the sixth order PRONY series and the constitutive equation was established. With the finite element software, the finite element model was programmed and then the thermal structure coupling analysis was realized. The formation of the fiber temperature field was supervised during the preheating process as well as the process of the fiber deformation was observed during the elongation process. In the aspects of drawing velocity and length respectively,multiple sets of experimental samples were obtained under the drawing velocity of 0.05mm/s,0.1mm/s and 0.15 mm/s respectively by the stretch platform with electric strip micro-heater. To validate the numerical simulation model, the results of simulation and experiments were compared in terms of the changing trend of the cone properties, the curves of the external shape, the cone waist diameter and the surface qualities of the cone. And the influence of process parameters was analyzed. It is showed that the results of simulation is consistent with the results of experiments within the acceptable error in aspect of the tapered waist diameter. Therefor the numerical model established in the paper has well accuracy.The equation of the biconical shape was achieved by curve fitting and data analysis obtained from the simulations of different drawing velocity. That the length of the fiber where the temperature belongs to the transition temperature replaces the length of the heated zone and increasing the degrees of exponential function to two improves the fitting accuracy of the classical exponential function. Using a third-order parabolic function to fitting the curve of the waist and transition improves the fitting accuracy.