脉冲时域相干合成技术主要通过对功率放大后的高重频脉冲序列进行时序合成，从而降低激光的重复频率，有效地提升输出脉冲的峰值功率与能量，避免放大过程中高峰值功率引起的非线性效应。该技术与空域相干合成相结合，能够突破单纤激光的性能极限，实现高能量、高平均功率和高峰值功率的超短脉冲激光输出，具有广阔的应用前景。介绍了超短脉冲光纤激光时域相干合成的基本原理和关键技术，综述了时域相干合成系统的发展历程及其关键技术的研究现状，重点介绍了近年来脉冲分割放大与脉冲相干堆积技术的研究进展，并对时域相干合成的不同技术路线进行了分析与比较，最后对其未来的发展方向进行了梳理，为相关领域的研究提供参考。

Broadband low-coherence light is considered to be an effective way to suppress laser plasma instability. Recent studies have demonstrated the ability of low-coherence laser facilities to reduce back-scattering during beam–target coupling. However, to ensure simultaneous low coherence and high energy, complex spectral modulation methods and amplification routes have to be adopted. In this work, we propose the use of a random fiber laser (RFL) as the seed source. The spectral features of this RFL can be carefully tailored to provide a good match with the gain characteristics of the laser amplification medium, thus enabling efficient amplification while maintaining low coherence. First, a theoretical model is constructed to give a comprehensive description of the output characteristics of the spectrum-tailored RFL, after which the designed RFL is experimentally realized as a seed source. Through precise pulse shaping and efficient regenerative amplification, a shaped random laser pulse output of 28 mJ is obtained, which is the first random laser system with megawatt-class peak power that is able to achieve low coherence and efficient spectrum-conformal regenerative amplification.

掺镱光纤是高功率激光器的核心材料，但在高能射线辐照后其应用性能会显著下降，因此有必要对掺镱光纤材料在辐照环境下的性能变化进行深入研究。采用改进型化学气相沉积法结合稀土螯合物掺杂制备了系列光纤预制棒及光纤，测试了光纤在不同剂量下射线辐照前后的高功率输出性能，以及光纤预制棒辐照前后的吸收光谱及镱离子荧光寿命。结果表明：小剂量辐照后掺镱光纤的高功率输出显著下降，通过预制棒吸收光谱可看出主要是因为伽马辐照后使掺镱光纤材料中Al的相关缺陷浓度增多，在可见光区域吸收损耗增加。Ce离子的掺杂通过缓减辐致铝氧空位中心（Al-OHC）色心缺陷的增加，减少Yb离子荧光寿命的下降，可在一定程度上抑制高功率掺镱光纤的辐致暗化。

We report an erbium-doped fiber laser passively Q-switched by a few-layer molybdenum disulfide (MoS2) saturable absorber (SA). The few-layer MoS2 is grown by the chemical vapor deposition method and transferred onto the end-face of a fiber connector to form a fiber-compatible MoS2 SA. The laser cavity is constructed by using a three-port optical circulator and a fiber Bragg grating (FBG) as the two end-mirrors. Stable Q-switched pulses are obtained with a pulse duration of 1.92 μs at 1560.5 nm. By increasing the pump power from 42 to 204 mW, the pulse repetition rate can be widely changed from 28.6 to 114.8 kHz. Passive Q-switching operations with discrete lasing wavelengths ranging from 1529.8 to 1570.1 nm are also investigated by using FBGs with different central wavelengths. This work demonstrates that few-layer MoS2 can serve as a promising SA for wideband-tunable Q-switching laser operation.