Roethlingshoefer Tobias, Onishchukov Georgy, Schmauss Bernhard, Leuchs Gerd
Opt Express. 2014 Dec 29;22(26):31729-34. doi: 10.1364/OE.22.031729.
The performance of cascaded in-line phase-preserving amplitude regeneration using nonlinear amplifying loop mirrors has been studied in numerical simulations. As an example of a spectrally efficient modulation format with two amplitude states and multiple phase states, the regeneration performance of a star-16QAM format, basically an 8PSK format with two amplitude levels, was evaluated. An increased robustness against amplified spontaneous emission and nonlinear phase noise was observed resulting in a significantly increased transmission distance.
