提出了一种八边形双包层结构的光子晶体光纤(PCF),并利用多极法对其色散特性进行数值模拟和分析。分析结果表明,内包层空气孔直径d1和空气孔间距Λ的改变对八边形双包层光子晶体光纤的色散特性影响较大,且色散曲线随d1/Λ的减小趋向平坦;而外包层空气孔直径d2的改变对其影响相对较小,同时,与d2的数值变化密切相关,当d2与d1相接近时,色散特性受其影响较大,当d2大于d1的2倍时,它的改变几乎不再影响光纤的色散特性。由此在1500 nm附近设计一种近零色散平坦光子晶体光纤。该理论结果对制备基于大功率激光用的掺杂光子晶体光纤和提高激光输出质量具有一定的借鉴作用。

The paper proposes octagonal structural photonic crystal fiber (PCF) with double cladding and simulated numerically its dispersion properties by the multipole method. The result shows that the dispersion properties of the octagonal structural photonic crystal fiber have large differentiation by changing Λ or d1. But they change slowly by changing d2,while they are dependent on the value of d2. When d2 is small,the dispersion properties change with d2,but when it is larger than twice of d1,the dispersion properties will no longer change. According to this characteristic,a nearly zero dispersion flattened photonic crystal fiber at 1500 nm is designed. The result has good effect on preparing the doping photonic crystal fiber which is used in the high power laser and improving the laser output quality.