We report the first 320-Gb/s all-optical wavelength multicast experimental demonstration in two-pump parametric amplifier, assisted by pump-pump self seeding. A single 320-Gb/s channel was successfully multicast to eight wavelengths with minimal conversion efficiency of -1 dB and less than 5-dB gain ripple. Self seeding was achieved by efficient spectral management and optimization of multiple-pump phase. The Q -factor penalty induced by the self-seeding process was found to be less than 1 dB compared to the single-pump parametric wavelength conversion.