10 Gbit/s all-optical non-return to zero-return-to-zero data format conversion based on a backward dark-optical-comb injected semiconductor optical amplifier

Abstract

By using a semiconductor optical amplifier backward injected by a dark-optical-comb pulse train at 10 GHz, we demonstrate a 10 Gbit/s all-optical nonreturn-to-zero (NRZ) to return-to-zero (RZ) format conversion of an incoming optical pseudorandom binary sequence (PRBS) data strieam. Both the polarity and the wavelength of data are conserved during format conversion. Without any preamplification, the extinction ratio of degraded optical NRZ PRBS data is greatly improved from 7.13 to 13.6 dB after NRZ-to-RZ conversion. An ultralow bit-error rate of 10(-12) at a data rate as high as 10 Gbits/s is obtained with a received optical power of-18.3 dBm. The converted RZ PRBS data exhibit a negative power penalty of > 3.7 dB compared with the NRZ PRBS data at a bit-error rate of 10(-12). (c) 2006 Optical Society of America