为了获得用于掺Yb3+脉冲光纤激光器的具有反常色散的光子晶体光纤, 设计了一种掺Yb3+铝硅酸盐玻璃纤芯的结构, 包层部分为普通的六边形结构, 分布着直径相同的空气孔, 其纤芯横截面为椭圆形, 在包层和纤芯之间设计了4个小椭圆空气孔。研究了包层的空气孔直径d与空气孔中心间距Λ以及二者的比值d/Λ这些参量变化时, 色散随波长变化的情况; 同时研究了4个小孔对色散和双折射的影响。结果表明, 这一结构的光子晶体光纤, 当Λ=2.3μm、d/Λ=0.5时色散呈现反常色散, 作为掺Yb3+脉冲光纤激光器的增益部分是可行的。该研究对掺Yb3+光子晶体光纤在脉冲光纤激光器方面的使用是有帮助的。

In order to get photonic crystal fiber with anomalous dispersion, which can be used as the gain part of a Yb3+-doped pulse fiber laser, a structure of photonic crystal fiber(PCF) with Yb3+-doped aluminosilicate glass core was designed. The cross-section of the core was oval, the cladding was the ordinary hexagonal structure with air holes in the same diameter, and there were four small air oval holes between the core and the cladding. The influences of air hole’s diameter d, pitch Λ and the ratio d/Λ of the cladding on the relationship between dispersion and wavelength were studied, as well as the influence of four small air oval holes on the relationship between dispersion and birefringence. The results show that when Λ is 2.3μm and d/Λ is 0.5, the anomalous dispersion is observed, and this photonic crystal fiber can be used as the gain part of a Yb3+-doped pulse fiber laser as well. The research is helpful for the use of Yb3+-doped PCF as the gain part of a pulse fiber laser.