Q-factor penalty evaluation in a cascade of all-, optical nodes using a re-circulating loop

The impact of all-optical node concatenation effects on the performance of a WDM transmission through 350 km of standard fiber is investigated with re-circulating loop experiments. A node of the OMEGA test bed is used to simulate a chain of fourteen nodes. Each link comprises a combination between one node (mux/demux, thermal optical switch and erbium-doped fiber optical amplifier) and 25 km of standard single mode fiber. Amplifier noise accumulation has been found to be the most detrimental effect.