Optical data exchange of 100-Gbit/s DQPSK signals

We experimentally demonstrate the phase-transparent optical data exchange between two differential quadrature phase-shift keying (DQPSK) signals by exploiting the signal depletion effect of non-degenerate four-wave mixing (FWM) in a highly nonlinear fiber (HNLF). Identical phase modulation is applied to the two pumps to suppress the stimulated Brillouin scattering (SBS) effect and enable the pump phase cancellation in the exchanged signals. Optical data exchange of 100-Gbit/s return-to-zero DQPSK (RZ-DQPSK) signals is implemented with a power penalty of less than 5 dB at a bit-error rate (BER) of 10(-9). Moreover, we investigate the impact of the temporal pump phase misalignment on the exchange performance and the dynamic range of the input signal power for the 100-Gbit/s RZ-DQPSK data exchange. The tolerance of the temporal pump phase misalignment is assessed to be +/-2 ps. An approximate 20-dB dynamic range of the input signal power is achieved.