Optical coherence tomography (OCT) was recently performed using a few-mode (FM) fiber to increase contrast or improve resolution using a sequential time-domain demultiplexing scheme isolating the different interferometric signals of the mode-coupled backscattered light. Here, we present an all-fiber FM-OCT system based on a parallel modal demultiplexing scheme exploiting a novel modally-specific photonic lantern (MSPL). The MSPL allows for maximal fringe visibility for each fiber propagation mode in an all-fiber assembly which provides the robustness required for clinical applications. The custom-built MSPL was designed for OCT at 930 nm and is wavelength-independent over the broad OCT spectrum. We further present a comprehensive coupling model for the interpretation of FM-OCT images using the first two propagation modes of a few-mode fiber, validate its predictions, and demonstrate the technique using in vitro microbead phantoms and ex vivo biological samples.

中文翻译：

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使用模态特定光子灯笼的全光纤少模光学相干断层扫描

最近使用少模 (FM) 光纤执行光学相干断层扫描 (OCT)，以使用顺序时域解复用方案隔离模式耦合背向散射光的不同干涉信号来增加对比度或提高分辨率。在这里，我们提出了一种基于并行模式解复用方案的全光纤 FM-OCT 系统，该方案利用了一种新型的模态特定光子灯 (MSPL)。MSPL 允许在全光纤组件中为每种光纤传播模式提供最大的条纹可见性，从而提供临床应用所需的稳健性。定制的 MSPL 专为 930 nm 的 OCT 设计，在宽 OCT 光谱上与波长无关。我们进一步提出了一个综合耦合模型，用于使用少模光纤的前两种传播模式解释 FM-OCT 图像，体外微珠体模和离体生物样品。