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结合光子晶体光纤(PCF)和拉锥的优点设计了一种色散平坦渐减PCF,用于在通信波段产生宽带超连续谱,并对该光纤中超连续谱的产生进行了详细的研究。结果表明:经过合理设计的PCF可以同时具有色散平坦和色散渐减的特性,并且其色散曲线沿光纤长度由反常色散区逐渐移动到正常色散区。这样的色散特性适合于产生宽带平坦的超连续谱。超连续谱形成的过程中以自相位调制效应为主,高阶非线性效应也起一定的作用,其中以拉曼散射效应的影响更为显著。另外,拉锥长度、光纤色散参量的渐减方式以及抽运脉冲的有效峰值功率和宽度对平坦超连续谱的产生均有着重要的影响。
Combining the advantages of photonic crystal fiber (PCF) and tapering cone, a dispersion flattened PCF is designed to produce broadband supercontinuum in the communication band. The generation of supercontinuum in this fiber is studied in detail. The results show that the properly designed PCF can have both flat dispersion and decreasing dispersion, and its dispersion curve gradually moves from the anomalous dispersion area to the normal dispersion area along the fiber length. Such dispersion characteristics are suitable for producing broadband flat supercontinuum. In the process of supercontinuum generation, the self-phase modulation effect is dominant, and the high-order nonlinear effect also plays a certain role. The Raman scattering effect is more significant. In addition, the taper length, the decreasing mode of the fiber dispersion parameter and the effective peak power and width of the pumping pulse all play an important role in the generation of flat supercontinuum.