Recently, the growing interest in few-mode fibers in telecommunications and high-power lasers has stimulated the demand for fiber mode decomposition (MD). Here we present a fast fiber MD method with a lensless fiber-point-diffraction interferometer. The complex amplitude at the fiber end is achieved by the polarization phase-shifting technique and the lensless imaging technique. Then, the eigenmode coefficients are determined by the mode orthogonal operations of the complex amplitude. In the experiment, the SMF-28e fiber containing 10 linear polarized modes at the wavelength of 632.8 nm is studied for MD. The decomposition of the 50 * 50 pixels interferograms takes only 0.0168 s. The similarity of the intensity patterns of the testing light is larger than 97% before and after the MD. This new, to the best of our knowledge, method can achieve fast and accurate 10-mode MD without using any imaging systems.

中文翻译：

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使用无透镜光纤点衍射干涉仪的快速光纤模式分解

最近，对电信和高功率激光器中的少模光纤的兴趣日益增长，这刺激了对光纤模分解（MD）的需求。在这里，我们提出了一种无透镜光纤点衍射干涉仪的快速光纤MD方法。光纤端的复振幅是通过偏振相移技术和无透镜成像技术实现的。然后，通过复振幅的模式正交运算确定本征模系数。在实验中，研究了包含10个线偏振模在632.8 nm波长处的SMF-28e光纤的MD。50 * 50像素干涉图的分解仅需0.0168 s。在MD之前和之后，测试光的强度图案的相似度大于97％。据我们所知，这是新产品，