All-optical wavelength conversion and signal regeneration of PAM-4 signal using a silicon waveguide.

We experimentally demonstrate on-chip all-optical wavelength conversion of 10-Gbit/s (9.35-Gbit/s net rate) 4-level pulse amplitude modulation (PAM-4) signal by exploiting degenerate four-wave mixing (FWM) in a silicon waveguide. The measured optical signal-to-noise ratio (OSNR) penalty of wavelength conversion is ~1 dB at a bit-error rate (BER) of 2 × 10^-3. Moreover, the use of wavelength conversion for PAM-4 signal regeneration is also demonstrated in the experiment.