Ultrahigh-speed, ultralarge-capacity, ultralong-haul transmission are key to solving bandwidth shortage problems. As transmission speeds approach 100Gbit/s or even 1Tbit/s per channel, the standard G.652.D low-water peak fiber will still be important in high-speed, long-haul systems. New requirements on the optical fiber have emerged because modulation methods have evolved, and new innovations have been made in coherent detection and devices. The repeater distance can be increased by further decreasing the ...