色散平坦渐减光纤中色散特性对超连续谱的影响

Effects of Dispersion Characteristics on Supercontinuum Generation in Dispersion Flattened-Decreasing Fiber

从频域全场方程出发研究了色散平坦渐减光纤中超连续谱(SC)的产生。结果表明,色散平坦渐减光纤的初始色散和色散斜率对超连续谱的产生有重要影响,当超连续谱宽度小于某一特定阈值时,谱宽随初始色散或色散斜率显著变化;而当超连续谱谱宽大于此值以后,谱宽随这两个参量的变化较缓慢。并且发现色散递减曲线为凸型的光纤比色散线性递减的光纤更有利于产生宽的超连续谱;而色散递减曲线为凹型的光纤不利于形成宽的超连续谱。计算表明经过优化选择光纤的色散参量,可以得到谱宽达330 nm的超连续谱。

Generation of Supercontinuum (SC) spectrum in the dispersion-flattened decreasing fiber has been studied by utilizing total field formation in the frequency. The initial dispersion and the fiber dispersion-decreasing rate have significant effects on the SC generation. SC bandwidth changes slowly when these two parameters are within certain threshold values, while it changes drastically when they exceed such values. The results also show that convex dispersion fiber is more favorable than the linear dispersion fiber in the generation of wide SC spectrum, while concave dispersion fiber is not suitable for the generation of wide SC spectrum. A 330 nm wide SC spectrum can be generated from a DFDF fiber with optimal dispersion characteristics.