European Terrestrial Fibre Upgrade Tsunami: G.657a Dethrones G.652.d

During most of my telecom career terrestrial long haul fibre was synonymous with the ITU's G652 standard. This is single mode optical fibre that has zero chromatic dispersion at the 1310 nanometer wavelength and good wavelength performance in the 1260 to 1625 nanometer range. This include the O, E, S and workhorse C bands. G.652d fibre quickly became the de facto standard for long haul terrestrial fibre optic networks. The G.652 standard was introduced in 1984. Its motivation was a dual purpose optical fibre suitable for data centers and long haul. Most optical equipment for internal data center traffic transmitted in the O band, which ranges from 1260 to 1390 nanometers. But long haul traffic faces significant attenuation as distances grow. This required repeaters, another source of capex and opex expense. It was already known that attenuation or the diminishing of light's intensity was minimized in glass at 1550 nanometers. The versatility of the G.652 standard made it hugel...