Pricking Sebastian, Giessen Harald
4. Physikalisches Institut and Research Center SCOPE, University of Stuttgart, Stuttgart, Germany.
Opt Express. 2010 Sep 13;18(19):20151-63. doi: 10.1364/OE.18.020151.
We demonstrate by means of numerical simulations of the generalized Nonlinear Schrödinger Equation that the variation of the diameter of a tapered fiber along the fiber axis can be used as a new degree of freedom to tailor the spectrum generated by ultrashort laser pulses.We show that, apart from the cross-section geometry of the fiber and the materials used for the core, cladding, and surrounding medium, the diameter profile along the fiber axis crucially influences the soliton dynamics, the temporal and spectral evolution as well as the generation of a supercontinuum. As an example, we have investigated a few centimeters long conical waists, which reveal large differences of the output spectra depending on the incoupling direction. For a decreasing fiber diameter, we find that, keeping the pulse energy constant, a lower input peak power may generate a broader supercontinuum. We attribute this result to the dynamics of higher-order solitons. A comparison of the simulated spectra to experimentally measured ones shows excellent agreement.
我们通过对广义非线性薛定谔方程的数值模拟表明，锥形光纤直径沿光纤轴的变化可作为一种新的自由度，用于调整超短激光脉冲产生的光谱。我们表明，除了光纤的横截面几何形状以及用于纤芯、包层和周围介质的材料外，沿光纤轴的直径分布对孤子动力学、时间和光谱演化以及超连续谱的产生有着至关重要的影响。例如，我们研究了几厘米长的锥形腰部，结果表明，根据入射方向的不同，输出光谱存在很大差异。对于光纤直径减小的情况，我们发现，在保持脉冲能量恒定的情况下，较低的输入峰值功率可能会产生更宽的超连续谱。我们将这一结果归因于高阶孤子的动力学。模拟光谱与实验测量光谱的比较显示出极佳的一致性。
