采用三维时域有限差分法对飞秒激光脉冲照明下锥形镀膜光纤探针内的光场进行了计算,研究了飞秒脉冲在探针中传输时的时域、频谱和相位特性,并分析了不同锥角和不同长度的探针对这些特性的影响.研究结果发现飞秒脉冲在探针中传输时出现了脉冲展宽、幅值振荡以及频谱分裂等现象,并且利用频谱和相位的变化特性初步解释了脉冲的展宽和脉冲振幅随时间周期性变化等现象. The three-dimensional finite difference time-domain method was used to calculate the optical field in the tapered coated fiber probe under femtosecond laser pulse illumination. The temporal, spectral and phase characteristics of the femtosecond pulse during probe transmission were studied and analyzed The effects of probes with different cone angles and different lengths on these characteristics were studied.The results show that there are some phenomena such as pulse broadening, amplitude oscillation and spectrum splitting when the femtosecond pulse is transmitted in the probe, and utilize the characteristics of spectrum and phase change A preliminary explanation of the pulse broadening and pulse amplitude cyclical changes with time and so on.