All-optical multicasting of a 320-Gb/s intensitymodulated return-to-zero signal with subsequent simultaneous sampling by a single parametric gate is experimentally demonstrated. The architecture used a two-pump broadband fiber-optic parametric amplifier for multicasting, and a single 40-GHz optical parametric sampling gate in a highly nonlinear fiber. Using this architecture, we demonstrate parallel demultiplexing of four 320-Gb/s tributary channels. All demultiplexed channels were measured with a -factor better than 15 dB.