Lee Szu-Yu, Parot Vicente J, Bouma Brett E, Villiger Martin
Harvard Medical School and Massachusetts General Hospital, Wellman Center for Photomedicine, Boston, MA, 02114, USA.
Harvard-MIT Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, 02140, USA.
Light Sci Appl. 2023 Feb 1;12(1):31. doi: 10.1038/s41377-022-01061-7.
Dispersion remains an enduring challenge for the characterization of wavelength-dependent transmission through optical multimode fiber (MMF). Beyond a small spectral correlation width, a change in wavelength elicits a seemingly independent distribution of the transmitted field. Here we report on a parametric dispersion model that describes mode mixing in MMF as an exponential map and extends the concept of principal modes to describe the fiber's spectrally resolved transmission matrix (TM). We present computational methods to fit the model to measurements at only a few, judiciously selected, discrete wavelengths. We validate the model in various MMF and demonstrate an accurate estimation of the full TM across a broad spectral bandwidth, approaching the bandwidth of the best-performing principal modes, and exceeding the original spectral correlation width by more than two orders of magnitude. The model allows us to conveniently study the spectral behavior of principal modes, and obviates the need for dense spectral measurements, enabling highly efficient reconstruction of the multispectral TM of MMF.
对于通过光学多模光纤（MMF）进行的波长相关传输特性的表征而言，色散仍然是一个长期存在的挑战。在一个小的光谱相关宽度之外，波长的变化会引发透射场看似独立的分布。在此，我们报告一种参数色散模型，该模型将MMF中的模式混合描述为指数映射，并扩展了主模的概念以描述光纤的光谱分辨传输矩阵（TM）。我们提出了计算方法，以便将该模型仅拟合到在几个经过明智选择的离散波长处的测量值。我们在各种MMF中验证了该模型，并展示了在宽光谱带宽上对完整TM的准确估计，接近性能最佳的主模的带宽，并且超过原始光谱相关宽度两个多数量级。该模型使我们能够方便地研究主模的光谱行为，并且无需进行密集的光谱测量，从而能够高效地重建MMF的多光谱TM。
