中文摘要：

从熊猫光纤在火焰中熔融拉仲的实际变形过程出发，通过数值计算和实验分析了应力区、偏振主轴间存在角度误差及熔融拉锥工艺参数等因素对附加损耗的影响机理，并指明应力区是影响熔锥型熊猫光纤耦合器附加损耗的主要原因。数值计算和实验结论对熔锥型熊猫光纤耦合器的工艺改进具有一定的指导意义。

英文摘要：

In this article theoretical analyses and experimental researches are made to study the excess loss mechanism of fused-tapered PANDA fiber coupler, respectively. The results show that the factors that affect the excess loss are the stress applying parts, the angular disparity between birefringent axes and the technological parameter of fused-elongation. This article introduces that the stress applying parts of PANDA fiber is the chief influencing factor of fused-tapered PANDA fiber coupler. The conclusion of researches can provide theoretical direction to improving the technology for PANDA fiber coupler.