(ITU) for very long distances.
ul(ULH). All of them use single mode fibres. Very Long Haul transmission links can bridge two stations at a distance of about 60 km at a wavelength of 1,300 nm and 120 km at 1,550 nm without intermediate amplification, depending on the wavelength. At a distance of about 600 km, a 3R regeneration
should be performed. Extremely long optical transmission distances can be bridged with Ultra Long Haul (ULH).