All-optical phase regeneration for DP-QPSK/8PSK signals based on dual-conjugate pump degenerate phase sensitive amplification

Abstract

An all-optical phase regeneration scheme for advanced modulated signals is proposed using dual-conjugate pump degenerate phase sensitive amplification. By engineered placement of the pump and signal wavelengths as well as the reduction of required conjugate harmonics’ order, viable phase squeezing of up to eighth-order is achieved. Feasibility of the scheme is verified through theoretical analysis and simulations. Key parameters such as signal-to-idler power ratio are investigated to optimize the phase regeneration performance. Combined with a subsequent phase-preserving amplitude regenerating device, the overall error vector magnitude decreases of regenerated DP-QPSK and DP-8PSK signals are about from 19% to 3% and from 9%. Furthermore, optical signal noise ratio improvements of 1.9 dB and 2.1 dB are achieved for phase noise of 20 degrees and 10 degrees, respectively. This shows the potential of the scheme to recover dual polarization signals’ quality and prolong transmission reach.