考虑非线性四阶折射率,推导了光脉冲在群色散单模光纤中传输的非线性方程,并得到孤子型解析解.同时指出在Sech型光纤脉冲压缩实验中,光强度的阈值. Considering nonlinear fourth - order refractive index, the nonlinear equations of light pulses propagating in group dispersion single - mode fiber are deduced and the soliton - type analytical solution is obtained. Meanwhile, the threshold of light intensity in the pulse compression experiment of Sech - type fiber is also pointed out.