BPSK Phase Regeneration Based on Second-Order Nonlinearities in Periodically Poled Lithium Niobate

With the advance of phase modulated optical systems all-optical regeneration of Phase-Shift Keying (PSK) signals has become a key functionality for future high-speed optical networks. This paper presents a phase-sensitive optical phase regenerator for Binary Phase-Shift Keying (BPSK) signals based on direct second-order nonlinear effects in Periodically Poled Lithium Niobate (PPLN) waveguides. Analytically and through simulations, the proposed set-up is found to require lower input power for efficient operation than more complex current solutions exploiting cascaded second-order nonlinear effects, while showing lower residual noise and the prospect of efficient intensity regeneration through saturation.