We report on a novel type of h-shaped pulse with femtosecond substructures from a linear-cavity semiconductor saturable-absorber mirror mode-locked thulium-doped fiber laser. It yields a stable nanosecond h-shaped pulse-train with a pulse envelope width ranging from 880 ps to 1.41 ns with a typical substructure pulse duration around 440 fs. The obtained h-shaped pulse is a noise-like pulse with strong robustness to pump power changes and environmental perturbation. It can also operate in the harmonic mode-locking regime. The scheme makes the structure compact and stable, and can obtain a MHz repetition rate, which is advantageous for real-life applications

中文翻译：

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来自2μm半导体饱和吸收镜反射锁模光纤振荡器的h形的类似噪声的脉冲

我们从线性腔半导体可饱和吸收镜锁模掺fiber光纤激光器报告了一种具有飞秒子结构的新型h形脉冲。它产生一个稳定的纳秒h形脉冲序列，其脉冲包络宽度为880 ps至1.41 ns，典型的子结构脉冲持续时间约为440 fs。所获得的h形脉冲是一种类似噪声的脉冲，对泵浦功率变化和环境扰动具有很强的鲁棒性。它也可以在谐波锁模模式下运行。该方案使结构紧凑稳定，可以获得MHz的重复率，对实际应用具有优势。