We report dispersion management based on a mismatched-grating compressor for a 100 PW level laser, which utilizes optical parametric chirped pulse amplification and also features large chirped pulse duration and an ultra-broadband spectrum. The numerical calculation indicates that amplified pulses with 4 ns chirped pulse duration and 210 nm spectral bandwidth can be directly compressed to sub-13 fs, which is close to the Fourier-transform limit (FTL). More importantly, the tolerances of the mismatched-grating compressor to the misalignment of the stretcher, the error of the desired grating groove density and the variation of material dispersion are comprehensively analyzed, which is crucially important for its practical application. The results demonstrate that good tolerances and near-FTL compressed pulses can be achieved simultaneously, just by keeping a balance between the residual second-, third- and fourth-order dispersions in the laser system. This work can offer a meaningful guideline for the design and construction of 100 PW level lasers.

基于光学微腔的光频梳具有阈值低、光谱宽及结构紧凑等特点，在精密测量与传感等领域具有重要的应用前景，因此近年来微腔光频梳成为国际研究热点。目前相关的研究都聚焦于红外波段锁模光频梳的产生原理和应用探索，虽然可见光波段的光频梳在精密光谱、原子钟及生物医学等领域有特殊应用价值，但是可见光频梳的实现极具挑战性。文中在简要阐述光频梳产生原理的基础上，介绍了在可见光波段实现光频梳的主要挑战，以及目前三种实现方案的研究进展，包括利用材料的二阶与三阶非线性效应、调节微腔的几何色散和模式强耦合效应调控色散来产生可见光频梳。

文中首次提出并验证了基于腔内色散管理实现飞秒光参量振荡器（OPO）光谱净化和稳定性提升的方法。对于高功率飞秒OPO，输出脉冲通常具有随时间无序变化的宽带不规则光谱，输出功率波动较大。利用铌酸锂（LiNbO₃）晶体在腔内引入额外的负色散，通过泵浦脉冲的时间滤波效应实现了干净平滑的窄光谱近转换极限的飞秒脉冲输出，光谱稳定性和功率稳定性得到了极大改善。该方法是一种实现飞秒OPO光谱净化和稳定性提升的灵活简便的方法，对于发展高功率的超短脉冲OPO具有重要的应用价值。

The mode-locked fluoride fiber laser (MLFFL) is an exciting platform for directly generating ultrashort pulses in the mid-infrared (mid-IR). However, owing to difficulty in managing the dispersion in fluoride fiber lasers, MLFFLs are restricted to the soliton regime, hindering pulse-energy scaling. We overcame the problem of dispersion management by utilizing the huge normal dispersion generated near the absorption edge of an infrared-bandgap semiconductor and promoted MLFFL from soliton to breathing-pulse mode-locking. In the breathing-pulse regime, the accumulated nonlinear phase shift can be significantly reduced in the cavity, and the pulse-energy-limitation effect is mitigated. The breathing-pulse MLFFL directly produced a pulse energy of 9.3 nJ and pulse duration of 215 fs, with a record peak power of 43.3 kW at 2.8 μm. Our work paves the way for the pulse-energy and peak-power scaling of mid-IR fluoride fiber lasers, enabling a wide range of applications.