Penalty-free wavelength conversion with variable channel separation using gain-switched comb source

We demonstrate penalty-free all-optical wavelength conversion of 10.7GBaud QPSK data using four-wave mixing and dual-correlated pumps derived from a gain switched comb source having large phase noise characteristics. We perform all-optical wavelength conversion over a 90GHz bandwidth and show that the non-degenerate scheme is independent of the phase noise of the dual-pumps as long as they have correlated phase noise. The RF linewidth of the beat tone of the comb lines with separations up to 90GHz is used to show excellent phase correlation between the comb lines. We obtain an error floor when all-optical wavelength conversion is performed using a single comb line from the gain-switched comb source as a pump in a partially degenerate scheme. The wavelength range for conversion is limited only by the spectral bandwidth of the gain-switched comb source.