Mitigating nonlinear propagation impairments of ultrashort pulses by fractional temporal self-imaging

We present a new approach to mitigate nonlinear impairments-mainly induced by self-phase modulation (SPM)-of high-repetition-rate optical pulses propagating through fiber-optic devices (amplifiers, propagation lines, etc.). The proposed approach is based on pulse division before nonlinear propagation, followed by pulse recombination using fractional temporal self-imaging (also known as the Talbot effect) in a dispersive medium. This approach directly addresses practical limitations of previous mitigation methods when applied to a train of pulses with a high repetition rate, in the gigahertz range and above. Effective reduction of SPM by a factor of ≃5 is experimentally demonstrated on picosecond optical pulses at a repetition rate of 6 GHz. The proposed method can be scaled to achieve higher SPM-reduction factors using a compact and robust fiber-optics scheme.