All-Optical DPSK Signal Regeneration Based on Cross-Phase Modulation

We present a concept for all-optical differential phase-shift keying (DPSK) signal regeneration, which reduces amplitude jitter and preserves phase information. At first, we consider a configuration to regenerate optical signals based on spectral broadening by self-phase modulation (SPM). An analytical approach of the induced phase shift demonstrates why SPM is not suitable for DPSK signal regeneration. We derive conditions for DPSK signal regeneration and present a configuration based on cross-phase modulation. Amplitude jitter is reduced effectively while preserving DPSK phase information. Numerical simulations prove the results and demonstrate the performance of DPSK signal regeneration.