Wavelength conversion of PDM 16-QAM signals by four wave mixing with a co-phase dithered pump

We demonstrate broadband wavelength conversion of a 256 Gb/s PDM 16-QAM signal using degenerate four-wave mixing (FWM) pumped by a single CW laser. By co-phase dithering both pump and signal, the FWM conversion efficiency is enhanced by 12.2 dB to ~48%, while suppressing most dither transfer to the idler, enabling the demodulation of the signal with a bit error rate well below the 4.5×10^-3 threshold limit for forward error correction with 7% overhead, and with an OSNR penalty of 1.2 dB compared to the back-to-back reference.