Advanced Low-Loss Fibers for High-Capacity Transmission: from Data Center to Undersea

We review recent progresses of advanced ultra-low-loss (ULL) fibers, introducing an 85μm
²
effective-area fiber with record-low-attenuation of 0.1474 dB/km at 1550 nm. We also highlight system demonstrations using ULL fibers and their relevance to DCI/metro and undersea network.