Semiconductor Optical Amplifier-Based Wavelength Conversion of Nyquist-16QAM for Flex-Grid Optical Networks

We experimentally demonstrate semiconductor optical amplifier (SOA)-based wavelength conversion of 3 × 25 GBd Nyquist-16QAM signal for a flex-grid network. The conversion efficiency (CE) and power penalty of each of three channels during single pumped SOA wavelength conversion are studied with respect to three different channel spacings (or frequency grids). The BER performance of all converted channels fall below the FEC threshold of 3.8 × 10
^-3
, even with a 50 GHz grid. The results show the tradeoff between channel spacing, CE, and BER power penalty. Closely packed channels, which clearly increase spectral efficiency, are also shown to decrease conversion power penalty, potentially counter balancing increased crosstalk levels. These results can be used to optimize routing and spectrum allocation strategy when SOA wavelength converter(s) are present in the optical link.