A Fiber-Based All-Optical 3R Regenerator for DPSK Signals

Analysis of an all-optical 3R regenerator for differential phase-shift keying (DPSK) signals is presented. Incoming DPSK signals impaired by noise are first demodulated to on-off keying (OOK) signals by a delay interferometer. The amplitude of the OOK signals is then stabilized by a fiber-based all-optical 2R regenerator. In a subsequent nonlinear fiber, locally generated optical clock pulses are phase-modulated by the stabilized OOK pulses and are output as regenerated signals. It is shown that significant phase-noise suppression is achieved by strong amplitude regeneration