Abstract: Based on thermal viscoelastic rheological theory and time-temperature equivalent principle, the thermal viscoelastic model of fiberglass under non-uniform temperature field is set up. By continuously adjusting its stiffness matrix and temper- ature field, the thermo-mechanical coupled numerical analysis of fiber coupler in the process of fused biconical taper is accomplished. The effect of technology parameters such as fused temperature and drawing speed on the manufacturing process is acquired. It is discovered that the maximum stress is in direct proportion to drawing speed, and fused temperature affects extremely on the manufacturing process. The change of fused temperature by 5 ℃ can lead to the change of maximum stress by 30%. It is found by experiment that the flame temperature change by 5~30 ℃, while the drawing speed is rather stable. A conclusion can be drawn by theory analysis and experimental research that it is the shift of fused temperature that induces the defaults of bad performance repeatability and unstable excess loss.

Key words: Fiber device, Finite element, Fused biconical taper, Viscoelastic rheology