The followings were discovered in the simulations of undersized waveguide : when the pulse width of input signal , a gaussian packet , is rather wide , the output signal distorted little . a superluminal group velocity 3 . 21c was revealed when the wave packet crossing 50mm forbidden region 对凹陷波导（ undersizedwaveguide ）的模拟发现：输入脉冲宽度较大的高斯波包，模拟结果显示输出波形失真较小，经过计算得到电磁波包穿过长50mm的截止区时，电场的幅度衰减了- 41 . 5db ，群速度为3 . 21c 。
The origin of supercontinuum spectrum ( sc ) generation in optical fibers has been shown to be the interplay between fiber nonlinear effects ( such as self phase modulation , cross phase modulation , stimulated raman scattering and stimulated brillouin scattering etc ) and group - velocity dispersion ( gvd ) 光纤中超连续谱supercontinuumspectrum ( sc )的产生源于光纤中各种非线性效应(如自相位调制效应、交叉相位调制效应，四波混频效应、受激raman散射与受激brillouin散射等)和群速度色散共同作用。
