Two-photon absorption effects on self-phase-modulation-based 2R optical regeneration

We theoretically investigate the influence of two-photon absorption (TPA) on the performance of self-phase-modulation-based signal regenerators using a split-step Fourier method. Simulations with 40-Gb/s return-to-zero data bit streams show that a device with TPA can improve the signal (higher output Q-factor) significantly more than a device with no TPA, and that the figure of merit of chalcogenide is close to optimal. This contrasts with the effects of TPA on nonlinear switching, which are always detrimental.