654 fiber is a single-mode fiber with a pure silica core, designed to minimize loss at a wavelength of 1550 nm. It was developed in the mid-1980s for long-distance submarine optical fiber systems, as it offers about 10% less loss than G. To support these high capacity systems in terrestrial backbone networks, low attenuation and large core area fibers compliant with Recommendation ITU-T G 654. E were introduced and have been extensively deployed worldwide. E, allow for the provision of an additional network margin that can be leveraged to enable reliable, high-data-rate transmissions over longer spans and extended reach. E fibre: a high-performance, sustainable networking solution. Sumitomo Electric. Why is the fate of the G.