AFL：2025年超大规模与AI数据中心模场直径（MFD）研究报告（英文版）

Specically, MFD is the diameter of the circle at which the optical intensity has fallen from its peak value at the center of the core to a prescribed minimum value of intensity (decreased by 1/e2 , where e is the base of the Natural Logarithm). The MFD of a ber is somewhat larger than the physical core, increasing at longer wavelengths and decreasing when the refractive index difference of the core and the cladding increases. For example, a ber with a core diameter of 8µm could have an MFD