运用渐近法计算了多模Bragg光纤的场分布、有效折射率、各模式的色散参量、群速度及TE₀₁模的能量速度。结果表明：各模式色散参量有正有负，但群速度都大于光速，而能量速度不大于光速。

This paper makes nse of asymptotic method to calculate the Bragg fiber with multi-mode's field distribution,the effective hollow indices,the dispersion parameters of various modes,the group velocities and the energy velocities of the TE₀₁ mode. The results show that the dispersion parameters of various modes are either positive or negative,but the group velocities are always greater than the light velocity. And the energy velocities are not greater than the light velocity.