We present a dual-color-soliton fiber laser at two different wavebands by nonlinear multimode interference. A saturable absorber (SA) with single-mode—multimode (MMF)—single-mode fiber structure is placed in the common branch shared by two sub-cavities. Saturable absorption effects can be simultaneously satisfied at 1.5 and 2 µm at a proper length of the MMF. Dual-color solitons can still remain, even by slightly tuning the length of the MMF. The periodical characteristic of this SA provides a flexible choice of MMF length, making it simple for simultaneous mode locking (SML) at two separate wavebands in practice. Our approach not only paves the way for SML at two or more wavebands by the MMF but also could lead to significant applications in pump-probe spectroscopy.

中文翻译：

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基于非线性多模干涉的双色锁模光纤激光器

我们通过非线性多模干涉在两个不同的波段提出了一种双色孤子光纤激光器。具有单模-多模（MMF）-单模光纤结构的可饱和吸收器（SA）放置在两个子腔共享的公共分支中。在适当长度的MMF下，饱和吸收效果可以同时满足1.5和2 µm的要求。即使略微调整MMF的长度，双色孤子仍然可以保留。该SA的周期性特性为MMF长度提供了灵活的选择，实际上使在两个单独的波段同时锁模（SML）变得简单。我们的方法不仅为MMF在两个或多个波段上的SML铺平了道路，而且还可能导致在泵浦探针光谱学中的重要应用。