All-optical wavelength conversion and five-channel multicasting for 20 Gbit/s QPSK signals in a silicon waveguide

Wavelength conversion and five-channel multicasting for 20  Gbit/s quadrature phase-shift keying signals have been experimentally demonstrated based on four-wave mixing in a silicon waveguide with digital coherent detection. The eye diagrams and constellation diagrams of the converted and multicasting idlers are successfully observed. Moreover, the bit-error rates (BERs) of the generated idlers are measured and the power penalties are all less than 0.7 dB at a BER of 3×10(-3).