Amplitude limiting of time-interleave-multiplexed OOK and DPSK signals based on four-wave mixing in a fiber

All-optical amplitude limiter of multiplexed on-off keying (OOK) and differential phase-shift keying (DPSK) signals based on saturation of four-wave mixing in a highly nonlinear fiber is demonstrated. Amplitude noise of OOK and DPSK signals is simultaneously suppressed. Thus, transmission performance of both signals is improved.