reshaping, reamplification, retiming (3R)
3R regeneration is the reprocessing of signals in optical transmission systems. This signal regeneration occurs every 600 km in long haul systems due to the attenuated and distorted data signals caused by the dispersion of the optical fib ers.
The reprocessing of laser signals in optical fib ers applies to the Long Haul, Very Long Haul, and Ultra Long Haul transmission systems. Since a simple reamplification of the light signal does not meet the high demands of optical transmission technology, a complete regeneration of the light signal consisting of reshaping, reamplification and retiming, called the 3R regeneration, takes place after about 600 km.
Only this method can restore a distorted and attenuated light signal. The restoration of the original signal shape is done by reshaping. In reshaping, the decoded light pulse is reshaped and noise is eliminated. The attenuation experienced by the optical signal is compensated by reamplification, a type of postamplification, and the clock signal is stabilized by retiming or reclocking.
If all three functions are not performed, the regeneration is a 2R regeneration or a 1R regeneration. A 2R regeneration performs reshaping and reamplification, and a 1R regeneration performs reamplification only.