All-optical 2R regeneration using passive saturable absorption

This paper reports on the regenerative properties and efficiency of an all-optical 2R regenerator based on a tandem of saturable absorber (SA) chips. A new SA structure allowing mark level equalization, which is a complement to the function of extinction ratio enhancement of the classical SA structure, is described. The experimental results at 42.6 Gbit/s show that amplitude fluctuations on both low and high power levels are significantly reduced with the SA tandem regenerator, and the system margin improvements in terms of receiver sensitivity and Q factor are obtained.