We investigate on bound-state mode-locking in the close-to-zero dispersion regime of an Er-fiber laser. A two-soliton bound state with 82 fs pulse duration and 0.58 ps pulse separation is achieved. Compound 2+1 type bound state solitons with ~100 fs pulse duration has also been observed. Both the double-pulse and the 2+1 type bound states could experience period-doubling bifurcations and exhibit the pumping hysteresis characteristics as the single pulse. To the best of our knowledge, this work provides the first observation of sub-100 fs bound solitons in a fiber laser. Such ultra-short bound state solitons show potential applications of multilevel coding unit for high-capacity telecommuncation systems.

中文翻译：

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锁模光纤激光器中低于 100 fs 的束缚态孤子和倍周期分岔

我们研究了 Er 光纤激光器接近零色散状态下的束缚态锁模。实现了具有 82 fs 脉冲持续时间和 0.58 ps 脉冲间隔的双孤子束缚态。还观察到了具有 ~100 fs 脉冲持续时间的化合物 2+1 型束缚态孤子。双脉冲和2+1型束缚态都可以经历倍周期分岔并表现出与单脉冲一样的泵浦滞后特性。据我们所知，这项工作首次对光纤激光器中的亚 100 fs 束缚孤子进行了观察。这种超短束缚态孤子显示了多级编码单元在大容量电信系统中的潜在应用。