为提升激光雷达的分辨率和作用距离，发射信号应选取具有较大时宽的宽带相位调制信号或宽带线性调频(LFM)信号。现阶段的激光频率调制技术难以在短脉宽内产生宽带LFM 信号，为此主要研究了基于马赫-曾德尔调制技术产生激光频段宽带LFM 信号的方法。在利用一个双平行马赫-曾德尔调制器(DPMZM)实现IQ 正交调制产生激光频段LFM 信号的基础上，提出了一种基于两个DPMZM 的激光频段三倍频LFM 信号产生方法。理论分析和仿真结果表明，该方法具有较好的谐波抑制能力，而且能够大幅度降低输入调制信号的带宽，可以在较低速率的数模转换条件下技术实现。

To improve the resolution and operating range of ladar, the transmission signal should be wideband phase-modulated signal or wideband linear frequency modulation (LFM) signal, for they have large time bandwidth product. It is hard to generate wideband LFM signal within short pulse width using the present laser frequency modulation technology. Therefore a method based on Mach-Zehnder modulation technique is studied to generate laser wideband LFM signal. Using one dual-parallel Mach-Zehnder modulator (DPMZM) can realize IQ quadrature modulation and generate laser LFM signal.Based on this, a method to generate laser-band frequency tripling LFM signal by using two DPMZMs is proposed. Theoretical analyses and simulation results show that the proposed method has good ability in harmonic suppression, and can greatly decrease the bandwidth of input modulation signal and can be realized with low-speed digital to analog conversion.