从时域的耦合波方程出发，数值研究了宽带钕玻璃激光谐波转换装置中输出三倍频脉冲的幅度调制效应，提出在三倍频的和频过程中加入一束窄带脉冲来抑制输出脉冲的幅度调制效应。研究结果表明，窄带脉冲的引入可大大减缓群速度失配对相位匹配带宽的限制，从而可以很好地抑制三倍频脉冲的幅度调制效应；对于目前所需要的带宽为1 THz的紫外脉冲，传统三倍频基本装置中的幅度调制深度为180%，采用上述方案后，三倍频脉冲的幅度调制深度降低到20%。

Based on the time-dependent nonlinear coupled wave equations, the amplitude modulation (AM) effect of third-harmonic pulse in the frequency conversion device of broadband Ndglass is studied numerically. To suppress this AM effect of output third-harmonic generation pulse, an added narrowband Ndglass laser pulse is mixed with the broadband laser pulse in the sum-frequency process of tripling configuration. Numerical results show that the limited phase-matching bandband due to the group-velocity-mismatch effects are substantially alleviated with the assist of a narrowband pulse. As a result, for a required third-harmonic wave with 1 THz bandwidth, the defined relative modulation of pulse intensity is as large as 180% in the conventional baseline design, while it will be reduced to only 20% by using the proposed scheme.