In this paper, we employ a symmetrical graded index multimode fiber-step index multimode fiber-graded index multimode fiber (GIMF-SIMF-GIMF) structure as artificial saturable absorber to achieve mode-locked operation in an Erbium-doped fiber laser. After optimizing the cavity length, pump power and orientation of polarization controller, noise-like pulse (NLP) is built in anomalous dispersion region experimentally. It is worth noting that except for the traditional NLP, a special NLP with unique features is obtained whose temporal and spectral properties are different from the known case on NLP reported before. According to the experimental results, we also acquire and compare properties of subpulse within NLP envelope with the change of pump power. Last but not least, harmonic of the peculiar NLP is found under appropriate cavity conditions.

在本文中，我们采用对称渐变折射率多模光纤阶跃折射率多模光纤渐变折射率多模光纤（GIMF-SIMF-GIMF）结构作为人工可饱和吸收体，在掺铒光纤激光器中实现锁模操作。在优化腔长、泵浦功率和偏振控制器方向后，通过实验在异常色散区域建立类噪声脉冲（NLP）。值得注意的是，除了传统的 NLP 之外，还获得了一种具有独特特征的特殊 NLP，其时间和光谱特性与之前报道的 NLP 上的已知案例不同。根据实验结果，我们还获取并比较了 NLP 包络内子脉冲的特性与泵浦功率的变化。最后但并非最不重要的一点是，在适当的腔条件下发现了特殊 NLP 的谐波。