直接相位调制可产生带宽可调的线性啁啾脉冲，可作为种子源用于啁啾脉冲放大系统中。对线性啁啾脉冲的产生过程以及啁啾脉冲在光纤中的传输放大过程进行了数值模拟与实验研究，实验获得了底宽为500 ps，带宽为0.69 nm 的线性啁啾脉冲。在此基础上提出一种全新的产生冲击点火种子脉冲的方式，即对光脉冲的局部进行调制与压缩以获得高对比度的种子脉冲，并对其进行了实验验证。实验中将一方波脉冲经调制压缩为对比度为2∶1 的阶梯脉冲，验证了该方法产生冲击点火种子脉冲的可行性。该方案为未来多种脉冲类型输出的惯性约束聚变(ICF)驱动器光纤前端系统的研制打下了研究基础。

A method to broaden the spectrum by direct phase modulation is proposed. The effects on the spectrum of modulation depth,modulation signal width, synchronization precision and different signal forms are investigated by numerical simulations. The results show that deeper modulation and more narrow modulation signal width lead to a more obvious effect and a broader spectrum of single modulation; different modulation signal widths require different synchronization precisions, and the narrow signals need a high-precision synchronization; compared to the parabolic signal, sinusoidal signal can lead to an obvious frequency modulation to amplitude modulation, which can bring down the compressibility and the signal to noise ratio. The experiment results of the central wavelength match well the simulation results.

提出一种对光脉冲直接相位调制进行光谱展宽的方法，对调制深度、调制信号宽度、同步精度和不同调制信号形状对输出光谱的影响进行了数值模拟。模拟结果表明，调制深度越大，调制信号宽度越小，对光谱的展宽效果越明显，单次调制展宽量越大；不同的调制信号宽度对同步精度有不同的要求，调制信号越窄，对同步精度要求越高；相比于抛物线型调制信号，正弦调制信号会带来光谱两侧明显的幅频调制，降低脉冲可压缩性和再压缩信噪比。实验结果与模拟数值结果相符。