超短激光脉冲在不同色散参量光子晶体光纤中传输的数值模拟

为了使得数值模拟更为精确,采用广义非线性薛定谔方程(GNSE)描述超短激光脉冲在光子晶体光纤中的传输演化过程,并利用二阶分步傅里叶方法通过求解方程,数值计算了相同脉宽和能量的超短脉冲在不同色散参量的光子晶体光纤中非线性传输和超连续谱的产生。比较了超短脉冲在光纤不同色散区传输时,高阶色散和非线性效应对超连续谱的产生以及对脉冲波形演化的影响。结果表明,相对于超短脉冲中心波长位于光子晶体光纤的正常和反常色散区,可以相应获得短波波段和长波波段的超连续谱输出,当超短脉冲中心波长位于零色散波长点时,通过色散和非线性效应的联合作用,更易于产生全波长段的平坦超连续谱。

Numerical Simulation on Propagation of Ultra-Short Laser Pulse in Photonic Crystal Fibers with Different Group Velocity Dispersion Parameters

For a more accurate numerical simulation, the generalized nonlinear Schrdinger equation is adopted to describe the evolution of ultra-short laser pulse propagating in photonic crystal fibers, and solved by using the second-order split-step Fourier method. The nonlinear propagation of ultra-short pulse with the same pulse width and energy, and generation of super-continuum spectrum are numerically simulated in different dispersion regions of photonic crystal fibers. In the different dispersion regions, the influence of high-order dispersion and nonlinear effects on the generation of super-continuum spectrum and pulse profile evolution are analyzed. The results show that, when the central wavelength of the input pulse is in the normal or abnormal dispersion regions, the super-continuum spectrum of short-wave band or long-wave band is obtained respectively (respect to the central wavelength). When the central wavelength is at the zero dispersion wavelength point of photonic crystal fibers, a flat super-continuum spectrum of the whole wave-band can be generated by combining the influence of high-order dispersion and nonlinear effect.