Light propagating through multimode fibers experiences multiple scattering, leading to complex speckle output patterns and significant dispersion. In this work, we propose a unique light state called the spectral-spatially correlated principal mode (S2${{\rm S}^2}$ principal mode) in multimode fibers. This mode demonstrates an ability to simultaneously manipulate the spectral correlation and spatial distribution of the output field under strong mode coupling. Such simultaneous control over multiple dimensions of the output field is achieved through measuring the generalized Wigner-Smith operator of the multimode fiber transmission. Experimental results showcase a substantial improvement in the spectral stability of the output spatial field profiles for these states. As a result, the S2${{\rm S}^2}$ principal modes offer precise localization of the output field within a designated region and mitigate distortions of the confined spots caused by modal dispersion. The advantages of S2${{\rm S}^2}$ principal modes are further showcased through their application in encrypting optical information transmission via multimode optical fibers. We anticipate these modes will find extensive applications in fiber optic communications, imaging, and spectroscopy, while also serving as inspiration for the discovery of other intriguing optical states.

中文翻译：

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多模光纤中光谱空间相关主模的产生及应用

通过多模光纤传播的光会经历多次散射，导致复杂的散斑输出模式和显着的色散。在这项工作中，我们提出了一种独特的光状态，称为多模光纤中的光谱空间相关主模（S 2${{\rm S}^2}$主模）。该模式展示了在强模式耦合下同时操纵输出场的光谱相关性和空间分布的能力。这种对输出场多个维度的同时控制是通过测量多模光纤传输的广义维格纳-史密斯算子来实现的。实验结果表明这些状态的输出空间场分布的光谱稳定性得到了显着改善。因此，S 2${{\rm S}^2}$主模式可在指定区域内精确定位输出场，并减轻模态色散引起的受限光斑的畸变。S 2${{\rm S}^2}$主模的优势通过其在多模光纤加密光信息传输中的应用而得到进一步展示。我们预计这些模式将在光纤通信、成像和光谱学领域得到广泛应用，同时也为发现其他有趣的光学状态提供灵感。