Eightfold 40–320 Gbit/s phase-coherent multiplexing and 320–40 Gbit/s demultiplexing using highly nonlinear fibers

We experimentally demonstrate 40-320Gbit/s phase-coherent multiplexing based on cross-phase modulation and subsequent 320-40Gbit/s demultiplexing using cross-phase-modulation-induced frequency shift in highly nonlinear fibers. An average penalty of approximately 7dB at a 10(-9) bit-error rate is observed after the nonlinear processes. We also show the generation of a phase-coherent 320GHz optical pulse train. A delay-line interferometer based on differential group delay is used to verify the phase coherence characteristic of the multiplexed 320Gbit/s signal and the generated 320GHz pulses.